Technical Information Package for Shell Thermal...

ABB Lummus Global

Technical Information Packagefor Shell Thermal Conversion Technologies

Proposal No. 3-3676

LGV SFOR 03-2000-01.001 (1996-06-20) DMS, propla0.dot , 1 30927LDR-0 /N24P0845.001 30927,0 Page 1 of 1

30927,0 DMS 1 0 SSVB - TECHNICAL INFORMATION PACKAGE INDEX 30927LDR-0

Index

1. INTRODUCTION

1.1 VISBREAKER HISTORY AND DEVELOPMENTS1.2 CHEMISTRY OF VISBREAKING1.3 CONVERSION AND VISCOSITY REDUCTION1.4 PRODUCT PROPERTIES AND USE

2. TECHNOLOGY OVERVIEW

2.1 INTRODUCTION2.2 SHELL SOAKER VISBREAKING TECHNOLOGY2.3 VACUUM FLASHER TECHNOLOGY2.4 SHELL DEEP THERMAL CONVERSION TECHNOLOGY2.5 SHELL THERMAL GASOIL PROCESS2.6 UPGRADING POSSIBILITIES FOR THE VISBREAKER UNITS2.7 PLANT AVAILABILITY

3. COMPETITIVE ADVANTAGES

3.1 COMPARISON SHELL SOAKER VISBREAKER VS. COIL VISBREAKER TECHNOLOGY3.2 LICENSING FROM ABB LUMMUS GLOBAL

4. EXPERIENCE SUMMARY

4.1 LICENSE SUMMARY

ABB Lummus Global B.V.

TECHNICAL INFORMATION PACKAGE --


30928,0 DMS 1 0 SSVB - TECHNICAL INFORMATION PACKAGE 1. INTRODUCTION 30928LDR-0

1. Introduction

1.1 VISBREAKER HISTORY AND DEVELOPMENTS

Thermal cracking units built before 1930 were plagued with coking and mechanical prob-lems. In these units, cracking was initiated in a heater and completed in a soaking drum.Runs were short, largely because the important parameters of cracking were not well under-stood.

Because of the problems with coke formation in the soaking drum, visbreakers after 1933were the coil cracking type. The soaking drum was eliminated and the heater outlet tem-perature increased, so that all cracking could take place in the heater. Improved heaters andcheap fuel largely contributed to this change.

Therefore, it was natural to build this same type of visbreaker when visbreakers becamepopular in Europe after 1960. One advantage was that the higher outlet temperature permit-ted deep flashing of visbreaker effluent without the application of high vacuum, so that in ad-dition to middle distillate a heavy gas oil could be produced. This could be cracked to yieldadditional middle distillates.

The depth of flashing was, however, not very impressive; and whenever larger quantities ofthermal cracker feedstock were required, a vacuum flasher for the residue was necessary.Most of the visbreakers built between 1960 and 1975 were combined with heavy distillatethermal cracking units.

These combination units were particularly useful in reducing the heavy-fuel-oil pour pointwhen waxy feedstocks were processed, such as those originating from Libyan crude oils.The thermal cracking residues from these feedstocks have pour points which can be 15 to20°C lower than those of the corresponding heavy gas oil feedstocks.

At about the same time that ABB Lummus Global started to design and construct severalvisbreaking units for Shell, a separate program was launched by Shell International to con-vert some old thermal cracking units into soaker-type visbreakers. The first of these unitswas started up in 1962 in Curaçao. It was soon followed by other units.

The main objective was to achieve a maximum visbreaking capacity for a given heater size.It soon appeared that the soaking units had a number of additional advantages.

Since the oil crisis in 1973, these advantages became so pronounced that Shell started toconvert its existing visbreaking-thermal cracking units into soaker-type visbreakers. Vacuumflashers were added to increase the production of thermal cracker feedstock. All new vis-breakers built by Shell are of the soaker type.

Refining developments have also played a role in the expansion of visbreaking. In the refin-ery configuration which has developed over the last 10 years the catalytic cracker has playeda predominant role in meeting gasoline requirements. This and cat cracker demands onvacuum gas oil, combined with the reduced demand for heavy fuel oil, has led to the presentupsurge in the construction of visbreakers for heavy vacuum residues.




TECHNICAL INFORMATION PACKAGE

1. Introduction


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In addition, visbreakers have been built or planned for long residue feedstock for the simplerhydroskimming refineries. These units can be built as single stage visbreakers with soakersor as combination units with an additional thermal cracker heater for heavy gas oil. Alter-nately, the heavy gas oil can be used as feedstock for the catalytic cracking unit.

1.2 CHEMISTRY OF VISBREAKING

A residual oil can be described as a colloidal system in which the dispersed phase consistsof micelle containing asphaltenes and high molecular weight aromatic malthenes. The con-tinuous phase contains the balance of the malthenes.

Asphaltenes are, in general, very complex high-molecular-weight hydrocarbons containingvery little hydrogen. They also contain sulfur, nitrogen, and oxygen, and have a strong aro-matic character and aliphatic side chains. They are very soluble in carbon tetrachloride, car-bon disulfide, and aromatic hydrocarbons, but not in light, paraffinic hydrocarbons. Malthe-nes are soluble in all kinds of hydrocarbons and in carbon disulfide.

The micelle consists of a core of asphaltenes to which high-molecular-weight aromatic hy-drocarbons from the malthene fraction are absorbed.

To these high-molecular-weight aromatic hydrocarbons, other hydrocarbons with a some-what higher hydrogen content are absorbed, until the micelle at their periphery contain hy-drocarbons with a hydrogen content about equal to that of the continuous malthene phase.

In a stable oil, the system of absorbed malthenes is such that all absorption forces are satu-rated. The micelle is then in physical equilibrium with the surrounding oil phase. In otherwords, the asphaltenes are peptized.

The absorption equilibrium can be disturbed in several ways, for instance, by adding hydro-carbons with a high hydrogen content (aliphatic hydrocarbons) and by increasing the tem-perature. Part of the absorbed compounds then dissolve in the continuous malthene phase,whereby the asphaltene cores precipitate.

During the visbreaking process, the continuous oil phase is cracked to smaller molecules.Also, new asphaltenes are formed from malthenes, and the malthene phase compositionchanges in character. Eventually the equilibrium between asphaltenes and malthenes isdisturbed to such an extent that part of the asphaltenes flocculate. At that point, the crackedfuel oil becomes unstable.

The cracking reactivity of the various hydrocarbons differs for the various classes of hydro-carbons, and decreases in the following order:



1. Introduction


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n Normal paraffinsn Iso-paraffinsn Cycloparaffinsn Aromaticsn Naphthenesn Polynuclear aromatics.

Paraffins are mostly cracked to smaller paraffins and olefins. Practically no carbon and hy-drogen are formed, so that no coke formation takes place in the primary cracking reaction.

An olefin is cracked to form either two smaller olefins or olefin plus diolefin. The diolefinsusually have short chains, and the amount formed is less at lower cracking temperatures.

Naphthenes and aromatics with long side chains are mainly cracked so that the side chainsare shortened to methyl or ethyl groups. Cracking of naphthene rings usually does not startat temperatures below 490°C.

Apart from cracking reactions, several other reactions take place, particularly when aromaticsand polynuclear aromatics are present. For instance, inter and intramolecular condensationcan take place as shown in Figure 1.

Figure 1



1. Introduction


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The condensation reactions are largely responsible for the formation of asphaltenes which, atincreasing conversion eventually leads asphaltenes to precipitate and, therefore, producesunstable fuel oil.

The concept of stability and how it is affected by visbreaking is illustrated by Figure 2. In thisdiagram, the corners represent three components of a residue: asphaltenes, paraffins, andaromatics. An area of immiscibility exists between the asphaltenes and paraffins, as alreadyimplied by the definition of asphaltenes, namely the material precipitated from an oil productby the addition of heptane or pentane.

Figure 2

Suppose a residue has a composition represented by point A, which is in the stable region.During the visbreaking process, asphaltenes are formed at the expense of aromatics, so thatthe composition moves into direction B. At too high a conversion, the composition can moveinto the unstable region.

In practice, a safe margin should always be kept to account for disturbances in the colloidalstructure because of prolonged storage at elevated temperature, oxidation by air and otherfactors.



1. Introduction


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Also, adding cutterstock to obtain a specified viscosity may have a negative effect on thestability, depending on the nature of the cutterstock. Possible effects of cutterstock additionare shown in Figure 2. The stability can either be improved or impaired as movement occursaway from or towards the region of immiscibility.

Figure 2 only gives a qualitative insight into the stability phenomena because aromaticity isnot the only yardstick for the suitability of cutterstock. A more quantitative insight can only beobtained by long term practical experience and laboratory testing.

1.3 CONVERSION AND VISCOSITY REDUCTION

The effect of visbreaking operation can be expressed in terms of the conversion or yield oflight products. Alternately, it can be expressed as the reduction in viscosity of the product.

The maximum allowable conversion is the amount of light material formed below a certaintrue boiling point (TBP) cut point; the remaining heavy material above that cut point is juststable.

For the Shell Thermal Conversion (SSVB) process, a cut point of 165°C is the normal refer-ence point. The conversion by this definition is different for various feedstocks because of thedifferences in chemical and colloidal nature, as has been noted.

If viscosity reduction is used as a yardstick, it refers to the viscosity of the material boilingabove 165°C in relation to the feedstock viscosity.

A few points should be made regarding the terms conversion and viscosity reduction:

1. Conversion at 165°C differs from actual conversion because the feedstock is also con-verted into light and heavy gas oil on one hand and asphaltenes on the other.

2. The stability requirement may differ from case to case. When the fuel oil has to be keptin storage for a long time, the limits are much more stringent than when the fuel oil isused immediately after it has been produced. Also, marine diesel installations aremuch more sensitive to plugging than large utility boilers. Therefore, the conversion tobe applied in practice depends largely on the circumstances.

3. The stability may change after the required cutterstock, but the fuel must be still stable.Particular care should therefore be exercised in cases where the quality and quantity ofcutterstock are not known beforehand. This is often the case in coastal refineries,where products are shipped without knowing the final destination. This is an additionalfactor to be taken into account in the day-to-day operation of a visbreaker.



1. Introduction


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4. The conversion of a visbreaker, in fact, is expressed in the amount of unwanted prod-uct because the goal is to reduce the viscosity of the 165°C-plus product. In otherwords, to reduce the viscosity of the combined distillate and residual fuel, the simulta-neous production of gas and gasoline is a necessary evil.

5. A perhaps more useful way to express the effect of visbreaking is the amount of astandard cutterstock needed to blend the visbroken residue to No. 6 Fuel Oil viscosityof 3,500 Sec. Redwood I (RI) at 100°F compared to the amount of cutterstock neededfor the feedstock. In Figure 3 this cutterstock quantity is given as a function of the con-version.

The reduction in cutterstock is not proportional to the conversion, but the effect be-comes less as the conversion increases.

Figure 3



1. Introduction


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1.4 PRODUCT PROPERTIES AND USE

As has been mentioned, the product properties for coil visbreaking and the Shell Soaker Vis-breaker process are, for all practical purposes, the same. The only pronounced difference isin the degree of saturation of the light components.

The C4 fraction from a Shell Soaker Visbreaker unit, for instance, contains about 35 percentolefinic materials, whereas for the coil process this runs from 40 to 50 percent.

This difference reflects the difference in cracking temperature. The quantities of gas pro-duced, about 2 wt. percent on feedstock, usually do not warrant the recovery of LPG. Mostoften, after removal of hydrogensulfide, this gas is used as fuel gas.

The average properties of gasoline and gas oil produced by the Shell soaker visbreaker arelisted in Table 1.

Table 1: Typical Soaker Visbreaker Product Properties

Gasoline (C5-165°C)

Specific gravity 0.74

F-1 clear 71

+ 1.5 ml TEL/gal 77

F-2 clear 64

+ 1.5 ml TEL/gal 68

Nitrogen, ppm 50

Bromine number, g/100 g 80

Gas Oil (165-350°C)

Specific gravity 0.87

Bromine number, g/100 g 25

Diesel index (after Hydrotreating) 50

Because the gasoline is olefinic, sensitivity and lead susceptibility are rather poor and so isthe octane number. To improve the octane number, the heavy portion of the gasoline can betreated in a catalytic reformer after having been hydrotreated first for saturation of olefins andremoval of sulfur.



1. Introduction


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If a multimetallic catalyst is used in the reformer, the nitrogen content must be reduced to alevel of 1 ppm by the hydrotreater. This may require a rather high reactor pressure and theuse of special catalysts.

The light portion of the gasoline, which has a research octane number (RON) of about 80,can also be added to the gasoline pool after Merox treating. Sometimes the total visbreakergasoline is reprocessed in a cat cracker, which improves the stability to such an extent thatonly a sweetening step is required for mercaptan removal.

The visbreaker gas oil as it comes from the unit is not color stable. Therefore, it should behydrotreated to make it suitable for distillate fuel oil use unless the quantity in the total fuelpool is limited. When the gas oil is used as residual fuel cutterstock, the hydrotreating stepcan be omitted unless it is required for desulfurization.

The most important property of the visbroken residue is its viscosity in connection with itsstability. The viscosity reduction that can be achieved is a function of the nature of the feed-stock, which determines the maximum possible conversion and feedstock viscosity. For thefinal product specifications, other properties (like specific gravity, sulfur content, and Conrad-son carbon content) are of interest. But these again depend on the feedstock characteristics.For a typical Middle East residue, visbroken residue properties are given in Table 2.

Table 2: Typical Feed/Residue Properties (Middle East Crude)

Feedstock550°C-plus

Visbroken Residue350°C-plus

Specific gravity 1.009 1.033

Sulfur, wt percent 3.5 3.7

Viscosity @ 50°C, cSt 46,000 16,000

Conradson carbon, wt. percent 17.0 23.9

The residue is mostly used as a heavy fuel oil component. In some refineries the residue issubject to vacuum flashing to obtain a distillate for use as supplemental cat cracker feed-stock. Part of the cycle oil produced in the cat cracker is then used as a cutterstock for thevacuum-flashed residue.

Another possibility is to utilize visbroken residue as feedstock for a partial oxidation unit forhydrogen or synthesis gas production. In this case, there are no stringent stability require-ments for the visbroken residue, so that substantially higher conversions are possible.

Shell Thermal Conversion processes are ideally suited for such an operation because anycoke formed as a result of the high conversion will not deposit on the heater tubes where theconversion is still within acceptable limits.



1. Introduction


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In refineries with lube oil facilities, the propane or butane asphalt from deasphalting opera-tions can also be used as feedstock to a visbreaker. Because of their extremely high viscos-ity, these asphalts are usually cracked in admixture with straight run residues. Visbrokenresidues from pure solvent asphalt would not meet some of the current fuel oil specifications.


30933,0 DMS 1 0 SSVB - TECHNICAL INFORMATION PACKAGE 2. TECHNOLOGY OVERVIEW

2. Technology Overview

2.1 INTRODUCTION

The three main configurations of Shell Thermal conversion technologies are:

n Shell Soaker Visbreaker without Vacuum Flashern Shell Soaker Visbreaker with Vacuum Flashern Shell Soaker Visbreaker with Vacuum Flasher and Distillate Conversion (Shell Thermal

Gasoil Process)

The main differences between the three configurations are the products they deliver. The ba-sic Shell Soaker Visbreaker without Vacuum Flasher produces gas, naphtha, and gasoil asadditional products. The Shell Soaker Visbreaker with Vacuum Flasher has an additionalheavy (or vacuum) gas oil product. In the Shell Thermal Gasoil process, the additional heavygasoil product is thermally converted to lighter gasoil.

The different technologies are described in more detail in the paragraphs that follow.







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2.2 SHELL SOAKER VISBREAKING TECHNOLOGY

2.2.1 OVERVIEW

STEAM

STEAM

GAS

NAPHTHA

GASOIL

RESIDUEVISBROKEN

VISBREAKERFEED

1 HEATER

2 SOAKER

3 FRACTIONATOR

12

3

The Shell Soaker Visbreaking process is ideally suited for the reduction of heavy fuel oilproduct via resid viscosity reduction and maximum production of distillates. Typical applica-tions include atmospheric and vacuum resids and solvent deasphalter pitch. The ShellSoaker Visbreaking process is jointly licensed by Shell and ABB.

ABB and Shell have extensive technical and commercial experience in soaker visbreaking,which results in highly efficient and reliable units. Over 80 Shell Soaker Visbreaking unitshave been built or converted from coil visbreakers and crude units.

Over 70% of the total visbreaking capacity built during the last 10 years was based on thisShell technology. It offers demonstrated advantages that include significantly lower fuel re-quirements, increased heater run length, and higher conversion operation with better viscos-ity reduction.





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The technology provides refiners with the means to conserve valuable cutter stock while stillproducing high quality, stable fuel oil. This conservation of valuable cutter stock, combinedwith fuel savings derived from the technology, offers an overall cost advantage that leads toproject payouts of one to two years.

Shell’s visbreaking process can be tailored to meet the refiners’ specific needs. A vacuumflasher can be added to obtain increased distillate recovery. Incorporating two-stage crackingin combination with a vacuum flasher will increase conversion and distillate recovery.

With typically 20% of the vacuum resid feed converted to distillate and lighter products, ShellSoaker Visbreaking is one of the lowest cost conversion process options.

2.2.2 PROCESS DESCRIPTION

Resid feed is pumped through preheat exchangers before entering the visbreaker heater,where the resid is heated to the required cracking temperature. The high efficiency heater isalso utilized to superheat stripping steam. Heater effluent is sent to the soaker drum wheremost of the thermal cracking and viscosity reduction takes place under controlled conditions.Soaker drum effluent is flashed and then quenched in the fractionator. Heat integration ismaximized in order to keep fuel consumption to a minimum. The flashed vapors can be frac-tionated into gas, gasoline, gasoil and visbreaker residue.

Liquid visbreaker residue is steam-stripped in the bottom of the fractionator and pumpedthrough the cooling circuit to battery limits. Visbreaker gasoil, which is drawn off as a sidestream, is steam-stripped, cooled and sent to battery limits. Alternately, the gasoil fractioncan be included with the visbreaker effluent. It is also possible to obtain a heavy vacuumgasoil fraction by adding a vacuum flasher downstream of the fractionator.

Cutter stocks, such as light cycle oil or heavy atmospheric gasoil, may be added to the vis-breaker residue/gas oil mixture to meet the desired fuel oil specification.





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2.2.3 YIELDS

Products yields are dependent on feed type and product specifications. Typical productyields for Middle East crude are given below.

Feed vacuum residue Middle East

Viscosity, cSt @ 100°C 770

Products in % wt. on feed

gas 2.3

gasoline ECP 165°C 4.7

gasoil ECP 350°C 14.0

residue ECP 350°C + 79.0

Viscosity 165°C plus, cSt @100°C 97.0

2.2.4 ECONOMICS

The investment is in the order of 1000 - 1200 US$/bbl installed excluding treating facilitiesand depending on capacity.

Utilities, typical per bbl @ 180°C:

fuel, Mcal 16

electricity, kWh 0.5

net steam production, kg 18

cooling water, m3 0.10





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2.3 VACUUM FLASHER TECHNOLOGY

2.3.1 OVERVIEW

STEAM

STEAM

GAS

NAPHTHA

VISBREAKERFEED

1 HEATER

2 SOAKER

3 FRACTIONATOR

4 CYCLONE

5 SHELL VACUUM FLASHER

4

1

3

CRACKEDRESIDUE

VACUUMFLASHED

5

HGO

LGO

2

The steady drop in heavy fuel oil demand has asked for further developments in VisbreakerTechnology. Shell Global Solutions has developed the Vacuum Flasher Technology, forwhich ABB Lummus Global acts as the authorized licensor.

Vacuum Flasher Technology has two major advantages when added to a Shell Soaker Vis-breaker:

I. Additional distillate products are being produced which are suitable for thermal crack-ing, catalytic cracking or hydrocracking to improve the overall performance of the refin-ery.

II. It produces a heavier, more viscous residue, which is still suitable for fuel blending orwhich can be gasified to produce hydrogen and can be used as fuel for a power plantdirectly.





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The Shell proprietary design of the transfer line between the atmospheric Fractionator andthe Vacuum Flasher and of the Vacuum Flasher internals minimizes coke formation andhence maximizes the runlength. This design also ensures a maximum yield of distillate prod-ucts while entrainment of heavy residue is avoided.

A large number of Vacuum Flashers downstream of visbreakers and thermal gasoil units arein operation. Shell Soaker Visbreaker units have successfully been revamped with the addi-tion of a Vacuum Flasher.

2.3.2 IMPLEMENTATION

When a refinery has a Visbreaker unit in operation, it is worthwhile to investigate whetheradditional distillate processing capacity is available. If this is the case, revamping the Vis-breaker unit using Vacuum Flasher technology will result in more distillate products, and thusimproved margins.

With a limited amount of investment, Vacuum Flashing technology offers two advantagesover Visbreaker units without a Vacuum Flasher:

n Additional distillate products are produced which are suitable for thermal cracking,catalytic cracking or hydrocracking. This results in improve economics of the refinery.

n It produces a heavier, more viscous residue, which is still suitable for blending into fueloil, and can be burned in the refinery fuel system. As an alternative, this residue streamcan be gasified to produce hydrogen and is then used as fuel for a power plant directly.

When a Vacuum Flasher is added to a Visbreaker unit, only minor modifications to the Frac-tionator system are required. The feed preheat train and product rundown will typically bechecked for the new situation.

The Vacuum Flasher concept has evolved from the crude / vacuum column design. In aVacuum Flasher the following products are produced:

n Heavy Gas Oil (HGO)n Vacuum Gas Oil (VGO)n Vacuum Flashed Visbreaker Residue

Typical product yields (in wt % on total feed to the Visbreaker unit) for moderate conversionrates are:

HGO 1 - 2 % cut point 350 - 365 °C

VGO 11 - 15% cut point 365 - 520 °C

VF Residue 65 – 70 % cut point 520 °C - plus





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By-Products:

VF Off-gas: 0.1 wt %

VF Sour Water 2.0 wt %

Slops 0.1 - 0.2 wt %

2.3.3 ECONOMICS

A calculation has been done for a typical visbreaker unit with a capacity of 4000 t/sd, proc-essing Middle East Vacuum residue with a viscosity of 3900 cSt at 100 °C. Below, the differ-ence in blending of a visbreaker unit and a visbreaker unit with Vacuum Flasher has been in-dicated.

VB

GAS

VB RES.

NAPHTHA

GASOIL

VFVB TAR

GASOIL

FUELOIL

FEED4000

76

164

460

3200

2680

1404

4544

HGO +VGO 620

VB

GAS

VB RES.

NAPHTHA

GASOIL

GASOIL

FUELOIL

FEED4000

76

164

460

3200

1164

4924

Figure 1: Blending example

The difference in gross margin between a Shell Soaker Visbreaker and a Shell Soaker Vis-breaker with Vacuum Flasher is approximately $5 per ton of residue feed. For a 4000 T/SDVisbreaker, the advantage is $ 6.6 Million per year. The difference in investment cost for theaddition of a Vacuum Flasher is approximately $ 6 Million. The pay out time for Shell VacuumFlasher technology is thus less than 1 year.

Actual pay out time depends on the location, product prices, design conversion, feedstockspecifications, etc.





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2.3.4 PROJECT EXECUTION

ABB Lummus Global has a history of executing various visbreaker revamp projects. A typicalrevamp project would start with assessment of operating data of the existing visbreakerplant, followed by a feasibility study phase, where different revamp options are evaluated inmore detail. Results from the feasibility study are discussed with the client and a plan will bemade for the next phase of the project which is the preparation of the basic design package.The basic design phase will be followed by the detailed engineering.

The Vacuum Flasher section can be built in a modular way and added next to the visbreakerplot. Given below is an example of a 3-D model of a visbreaker unit which was originally builtby Shell and for which a Vacuum Flasher was added later on. The Vacuum Flasher sectionhas been highlighted.

3D model of visbreaker unit with Vacuum Flasher





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2.4 SHELL DEEP THERMAL CONVERSION TECHNOLOGY

2.4.1 OVERVIEW

STEAM

STEAM

GAS

NAPHTHA

LGO

VISBREAKERFEED

1 HEATER

2 SOAKER

3 FRACTIONATOR

4 CYCLONE


4

1

2

3

CRACKEDRESIDUE

VACUUMFLASHED

5

HGO

The Shell Deep Thermal Conversion process fills the gap between visbreaking and coking. Itwas developed based on many years of experience with the Shell Soaker Visbreaking proc-ess. The process yields a maximum of distillates by applying deep thermal conversion of thevacuum residue feed and by vacuum flashing of the cracked residue. High distillate yieldsare obtained while still producing a stable liquid residual product, referred to as vacuumflashed cracked residue. This stream, which is not suitable for blending to commercial fuel, isused for specialty products, gasification and/or combustion, e.g. to generate power and/orhydrogen.

The Shell Deep Thermal Gasoil process is a combination of the Shell Deep Thermal Conver-sion and the Shell Thermal Gasoil processes. In this alternative high conversion scheme, theheavy gasoil (HGO) from the atmospheric Fractionator and the vacuum gasoil (VGO) fromthe vacuum flasher are converted in a distillate thermal conversion heater into lower boilingpoint gasoil.





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Deep Thermal Conversion

Preheated vacuum residue is charged to the visbreaker heater and from there to the soaker,where the deep conversion takes place. The conversion is maximized by controlling the op-erating temperature and pressure. The soaker effluent is routed to a cyclone and the cycloneoverheads are charged to the flash zone of the atmospheric Fractionator to produce the de-sired products like gas, LPG, naphtha, kero and gasoil. The fractionator bottoms are routedto a vacuum flasher, which recovers additional gasoil and vacuum gasoil (VGO). Vacuumflashed cracked residue is routed for further processing depending on the end use.

Deep Thermal Gasoil

The heavy gasoil from the atmospheric Fractionator and the VGO from the Vacuum Flasherare cracked in a distillate thermal conversion heater. The product from the thermal conver-sion heater is routed to the Fractionator.

2.4.3 YIELDS

Products yields are dependent on feed type and product specifications. Typical productyields for Middle East crude are given below.

Feed vacuum residue Middle East



gas 4.0



waxy distillate ECP 520°C 22.5






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2.4.4 ECONOMICS

The investment amounts to 1300 - 1600 US$/bbl installed excluding treating facilities anddepending on the capacity and configuration.


fuel, Mcal 26








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2.5 SHELL THERMAL GASOIL PROCESS

2.5.1 OVERVIEW

STEAM

STEAM

GAS

NAPHTHA

GASOIL

CRACKEDRESIDUE

VACUUMFLASHED

VISBREAKERFEED

1 HEATER

2 SOAKER

3 FRACTIONATOR

4 CYCLONE

5 DISTILLATE HEATER


4

6

VGO

HGO

5

1

2

3 GAS

ABB offers the Shell Thermal Gasoil process to upgrade atmospheric residue and waxy dis-tillate. Originally developed in the 1960s, continued improvement in the Shell-designedsoaker drum and heater designs resulted in the present Thermal Gasoil technology, a com-bination of three mature, well-proven Shell technologies:

n Soaker Visbreakingn Vacuum Flashingn Thermal Cracking

Shell was the first to develop and employ soaker visbreaking technology. The soaker drum,with patented internals, achieves higher conversion and improved viscosity reduction com-pared to other visbreaking technologies.





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ABB and Shell have extensive experience in the design of thermal conversion processes.With continual feedback from operating units, we are able to provide advanced designs andpractical advice on operational matters. Shell’s ongoing research and development in ther-mal cracking technology and equipment design assures the availability of the most up-to-date know-how in this field.


Atmospheric residue is pumped through feed preheat exchangers, where the feed is heatedagainst cracked residue, and then routed to the visbreaker heater. In the heater, the feed isheated to the required cracking temperature and routed to the soaker where the majority ofthe thermal cracking occurs under controlled conditions. The soaker effluent is routed to acyclone and the cyclone overheads are charged to the flash zone of the atmospheric frac-tionator.

In the top section of the Fractionator, the soaker effluent is split into four fractions: heavygasoil, gasoil, naphtha and offgas. The gasoil is taken from the Fractionator as a draw off,steam-stripped in a side stripper to improve the flash point, and sent to the battery limit. Theoverhead vapors are condensed in a two-stage condensing system: in the first stage, onlythe reflux is condensed; in the second stage, the naphtha product is condensed. From theoverhead system, the offgas and naphtha are sent to the battery limit.

Inside the Fractionator, the liquid is quenched to prevent further cracking and then steam-stripped. The hot Fractionator bottoms, together with the cyclone bottoms, are routed to thevacuum flasher where the vacuum gasoil (VGO) is recovered. The VGO is sent, togetherwith the heavy gasoil from the atmospheric Fractionator, to a distillate thermal conversionheater where it is partly converted into lower boiling fractions. The heater effluent is routed tothe flash zone of the atmospheric Fractionator. The unconverted heavy gasoil is recovered inthe Fractionator and Vacuum Flasher and is recycled back to the distillate thermal conver-sion heater to maximize the gasoil yield.

The vacuum-flashed residue is cooled against the VGO and then by steam generation. Thecooled residue is sent to fuel oil blending where it is blended with gasoil product and/or othercutter-stocks to meet the specified fuel oil viscosity.





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2.5.3 YIELDS

Depend on feed type and product specifications.

Feed atmospheric residue Middle East



gas 6.4




Viscosity 165°C plus, cSt @100°C 7.7

2.5.4 ECONOMICS

The investment amounts to 1400 - 1600 US$/bbl installed excluding treating facilities anddepending on capacity and configuration.


fuel, Mcal 34








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2.6 UPGRADING POSSIBILITIES FOR THE VISBREAKER UNITS

Three well-proven advanced technologies from Shell are now available for licensing fromABB Lummus Global, that provide an economically feasible extension and upgrade of theVisbreaker Unit.

2.6.1 SHELL VACUUM FLASHER TECHNOLOGY

The visbreaker residue still contains a considerable amount of heavy gasoil (TBP range ap-proximately 350-500 °C) that can be used as an attractive supplementary feed to further up-grading processes such as catalytic cracking or hydrocracking. Heavy gasoil is recovered byvacuum flashing of the atmospheric visbreaker residue. Shell has accumulated a vast wealthof research and operational experience in visbreaker residue vacuum flashing. Shell’s Vac-uum Flasher technology is available for licensing through ABB Lummus Global. The mainfeatures of the Shell Vacuum Flasher Technology are:

n Excellent distillate yield, combined with high product qualities of vacuum flasher distil-lates.

n Superior runlength, when compared to conventional, open art, vacuum flashers.

STEAM

STEAM

GAS

NAPHTHA

VISBREAKERFEED

1 HEATER

2 SOAKER

3 FRACTIONATOR

4 CYCLONE


4

1

3

CRACKEDRESIDUE

VACUUMFLASHED

5

HGO

LGO

2





--

2.6.2 SHELL THERMAL GASOIL TECHNOLOGY

Shell Thermal Gasoil Technology is utilized for the production of middle distillates from at-mospheric residue by a combination of visbreaking and distillate thermal conversion. Heavydistillates withdrawn from the Visbreaker atmospheric Fractionator and vacuum flasher arefurther cracked in a separate thermal conversion furnace. This process combines the ad-vantages of Shell’s visbreaker process with distillate conversion furnace design. The ShellThermal Gasoil Technology provides an excellent low cost solution for reducing fuel oil pro-duction. The distillate Thermal Conversion Technology (based on converting distillate feed)can also be licensed separately.

STEAM

STEAM

GAS

NAPHTHA

GASOIL

CRACKEDRESIDUE

VACUUMFLASHED

VISBREAKERFEED

1 HEATER

2 SOAKER

3 FRACTIONATOR

4 CYCLONE

5 DISTILLATE HEATER


4

6

VGO

HGO

5

1

2

3 GAS

2.6.3 SHELL DEEP THERMAL CONVERSION TECHNOLOGY

Shell’s latest development in the area of Thermal Conversion is the Shell Deep ThermalConversion Technology. Due to the increase in non-fuel oil outlets of thermally convertedresidues, new opportunities have arisen for thermal conversion. The use of undiluted ther-mally converted residues removes the usual stability constraint allowing substantially in-creased conversion levels in the operation of a Thermal Conversion unit. In practice how-ever, the maximum achievable conversion levels are often limited by the rapidly decreasingunit run length. Shell has been able to improve the design and operation of the unit such thathigh conversion levels can be achieved while maintaining long run lengths.





--

This technology closes the gap between visbreaking and delayed coking. It realizes most ofthe delayed coking upgrading while avoiding the drawbacks of solids handling. The residualproduct of Deep Thermal Conversion remains liquid and is referred to as vacuum flashedcracked residue.

The main characteristics of the technology are listed below:

n Can be applied to both Visbreaking as well as Thermal Gasoil units.n Includes Shell Soaker Visbreaking technology.n Includes Shell Vacuum Flasher technology.n Typically 45-55 %wt of Vacuum Residue is converted to distillate products.n Revamp of an existing unit is possible.n Liquid residual product.n Includes both design and operational know-how.

The main benefits of Shell Deep Thermal Conversion technology compared to ‘high conver-sion’ operation on traditional thermal conversion technology can be summarized as follows:

n Substantially higher conversion.n Longer run length and higher on stream time.n Higher distillate yields from Vacuum Flasher.n Lower capital expenditure.n Additional gasoil from Vacuum Flashern Improved operability due to use of pressure and temperature as control variables.

On the other side the main benefits of Shell Deep Thermal Conversion technology comparedto delayed coking technology can be summarized as follows:

n Slightly lower conversionn Better quality productsn Higher selectivity to gasoiln Substantially lower capital expendituren No solids handling.





--

2.7 PLANT AVAILABILITY

Proper design of the Visbreaker Heater utilizing the expertise of Shell/ABB Lummus Globaland proper operation supervision, results in an onstream time of these heaters of about 350days per year. The fractionation section, the soaker and the heat exchangers in the unit havefar longer run lengths. The availability of the Visbreaker Unit is expected to be as shownbelow:

Number of decoking shutdowns per year 1

Average length of decoking shutdown in days 8

Average total scheduled shutdown days per year1 14

Average unscheduled shutdown days per year 1

Available stream days per year 350

Plant availability 95.9%

Onstream availability 99.7%

1 Average scheduled shutdown days per year is based on one major turnaround every four years and includes de-coking shutdowns.


30935,0 DMS 1 0 SSVB - TECHNICAL INFORMATION PACKAGE 3. COMPETITIVE ADVAN-

3. Competitive Advantages

3.1 COMPARISON SHELL SOAKER VISBREAKING VS. COIL VISBREAKER TECHNOLOGY

The Shell Soaker Visbreaking Process is a low-temperature, long residence time crackingtechnique. It offers significant advantages over conventional heater coil cracking in opera-tional flexibility, investment and operating cost. Developed by Shell, the Soaker VisbreakingProcess is available worldwide from ABB Lummus Global.

The Shell Soaker Visbreaking process is a mature and proven technology. It is currently ap-plied in over 80 units throughout the world, for a variety of feedstocks and in different con-figurations. The process produces a residue, which after final blending yields fuel oils thatmeet all commercial stability requirements.

The Shell Soaker Visbreaking process has proven to offer many benefits that have made itthe leading Visbreaker technology in the world:

n Up to 15% Capital Investment SavingsThe major part of the thermal conversion takes place in the soaker drum. This soakerenables a lower temperature, leading to capital investment savings of up to 15% oreven more, when compared to conventional coil visbreakers. The lower temperaturedownstream the heater results in a smaller heater, and smaller heat exchange equip-ment.

n Up to 30% Fuel SavingsThe lower heater outlet temperature results in a fuel saving of up to 30% compared toconventional coil visbreakers. Due to the lower heater outlet temperature, also lesswaste-heat steam is generated. Typically, refineries have little demand for low-levelsteam. Therefore, the value of low-level steam is not very favorable under these condi-tions. Overall, economics are best when fuel consumption is small, and the amount ofsteam generation is minimal.

n Longer Run-lengthsLower temperatures mean lower heater tube wall temperatures. This results in reducedcoking, extended tube life and run lengths that are at least three times the run length ofconventional visbreakers. Run lengths of more than a year in a Shell Soaker Vis-breaker are common, compared to a run length of 3 to 6 months for a Coil type Vis-breaker. The improved run length gives the Shell Soaker Visbreaker the same on-stream factor as the upstream crude and Vacuum Distillation units. In contrast, the CoilVisbreaker is down for decoking for at least two times per year for five days. Duringthese extra ten days of downtime each year, the vacuum residue has to be blended tofuel viscosity without visbreaking.

n Enhanced Operating FlexibilitySoaker visbreakers have both the heater outlet temperature and the soaker pressure(i.e. reactor residence time) as variables for process control. This provides more flexi-bility in the operation of the visbreaker.







--

n High Turndown RatioThe enhanced operating flexibility ensures stable and controlled operation at 50% ofthe design capacity. ABB Lummus has licensed a Shell Soaker Visbreaker to a Euro-pean client that was designed to run at a turndown of 44% of design capacity.

n Up to 2% Higher Gasoil GainThe configuration and the internals of the Shell Soaker ensure an optimal flow pattern.It minimizes back mixing and hence gives an optimal residence time distribution to geta higher conversion at constant residue stability. As a result of the application of theseinternals, the gasoil gain of the Shell Soaker Visbreaker process is 1-2% higher thanthat in a process using soakers without internals at the same residue stability.

n Well-proven TechnologyThe large number of designs made for Shell Soaker Visbreaker units and the continu-ing feedback received in many operating units have built up vast experience on soakercracking. It is this experience which provides a guarantee for both advanced designsand practical advice on operational matters.

3.2 LICENSING FROM ABB LUMMUS GLOBAL

Licensing the Shell Soaker Visbreaking Technology from ABB Lummus Global gives accessto a unique package of services:

n Latest Know-how AvailableShell's ongoing research and development effort in the field of both technology andequipment for soaker cracking assures the availability of a most up-to-date know-howin this field.

n Active SupportRegularly, conference meetings are organized for licensees by Shell and ABB LummusGlobal to exchange information between participating operating companies on a varietyof subjects related to soaker cracking. Training and appropriate routine and trouble-shooting assistance to operators or during EPC and commissioning phases is providedtailor-made to the Owner’s requirements.

n Pilot Plant FacilitiesPilot plant facilities are available for the evaluation of unfamiliar feedstocks for new de-signs or to assess for clients the cracking characteristics - and thus the economic value- of new feedstocks.

n Residue Stability Analyzer ("P-value Analyzer")A quality analyzer for residue stability is available to licensees to monitor unit operationand to make sure that the unit is continuously operated at optimum severity.





--

n Stability and Blending Know-howProprietary know-how on the stability of residues and on blending of fuel oils is avail-able to licensees. Together with the readings of the residue stability analyzer, the in-formation enables the operator to make the link between unit operation and fuel blend-ing - a link indispensable to optimize the cracking operation.

n Full EPCOM CapabilitiesABB Lummus Global, as a leading contractor, can offer full EPC of visbreaker plants onlump sum turnkey basis, extended with operations and maintenance tailored to any re-quirement.

Once an appropriate level of understanding has been reached, potential licensees aregiven the opportunity to visit operating plants, so that they can make their own judg-ment on such issues as process operability, maintenance and onstream time. A frankexchange of ideas is considered necessary prior to the initiation of any design work.This will assure that the plant design is tailor-made to Owner's requirement.

Once a license agreement is concluded, the know-how is provided by ABB LummusGlobal in the form of a complete basic engineering package. The information in this ba-sic engineering package is very complete and will enable any qualified engineeringcontractor, chosen by the Owner, to perform the detailed engineering, procurement andconstruction of the plant.

During the detailed engineering phase of the project, ABB Lummus Global will reviewand approve selected areas of EPC contractor's detailed design. This is a necessaryrequirement to ensure that the design is being carried out in the correct manner andguarantees will be met.


30937,0 DMS 1 0 SSVB - TECHNICAL INFORMATION PACKAGE 4. EXPERIENCE SUMMARY

4. Experience Summary

4.1 LICENSE SUMMARY

ABB Lummus Global became involved in licensing the Shell Thermal Conversion process in1979. Since that time, several Shell Thermal Conversion units have been designed and/orbuilt by Shell and ABB Lummus Global, for processing a variety of feedstocks from long resi-due to propane asphalt.

The vast majority of the Thermal Conversion capacity in the world added in the last 15 yearsis based on Shell’s technology. On average, four new Thermal Conversion units are licensedeach year, which is illustrated in the graph below:

0

3

6

9

12

15

1952 1957 1962 1967 1972 1977 1982 1987 1992 1997 2002

Year

Un

its

Lic

ense

d

0

90,000

180,000

270,000

360,000

450,000

Cum

ulat

ive

Cap

acity

, T/Y

r

Units Licensed

Cumulative Capacity







--

Although initially only Shell Soaker Visbreaker technology was available for licensing, moreadvanced thermal conversion technologies were added later to the Shell Thermal Conver-sion portfolio. The table below shows the number of licenses and capacity for the differenttechnologies.

CapacityMT/D

Number ofLicenses

Shell Soaker Visbreaker Technology 248,797 61

Shell Soaker Visbreaker Technology + Vacuum Flasher 85,500 22

Shell Thermal Gasoil Technology 50,650 15

Shell Deep Thermal Conversion technology 17,700 4

Total 402,647 102

A more detailed list is attached on the next few pages




SSVB = Shell Soaker Visbreaker Technology SDTC Shell Deep Thermal Conversion Technology

STG = Shell Thermal Gasoil Technology SVF Shell Vacuum Flasher Technology


--

LicenseeYear

LicensedCapacity,

MT/D Technology Note

Lukoil-Permnefteorgsyntez,Perm, Russia

2001 2900 SSVB

Samir,Mohammedia, Morocco

2001 4500 SSVB

Saras SpA,Sarroch, Sardinia, Italy

2001 7200 SSVB / SVF Upgrade

TNK-Ukraina,Lisichansk, Ukraine

2001 3500 SSVB

Chennai Petroleum Corp. Ltd. (CPCL),Manali, Chennai, India

2000 3600 SSVB / SVF

Deutsche Shell AG - TGU-1,Godorf, Germany

2000 2700 SVF / STG Upgrade



Petrola Hellas,Elefsis, Greece

2000 3207 SSVB

Petronor,Somorrostro Vizcaya, Spain

2000 7250 SSVB / SVF

DEA Mineraloel AG,Heide, Germany

1999 2400 SSVB / SVF

Nagarjuna Oil Corp Ltd.,Cuddalore, India

1999 2150 SSVB

Samarec,Saudi Arabia

1999 7700 SSVB

AGIP/Hohbond Refinery,Haikou, Hainan Island, China

1998 3600 SSVB / SVF







--

LicenseeYear

LicensedCapacity,


Czech Refining Company,Litvinov, Czech Republic

1998 2500 SSVB / SVF /SDTC

Repsol YPF,La Pampilla, Lima, Peru

1998 4250 SSVB / SVF

Saudi Aramco-Shell (Sasref),Al-Jubail, Saudi Arabia

1998 5250 SVF / STG

TAIF,Nizhnekamsk, Russia

1998 5400 SSVB

Arpechim SA,Pitesti, Romania

1997 2400 SSVB

Dansk Statoil AS,Kalundborg, Denmark

1997 3120 SSVB Upgrade

Mangalore Refinery & Petrochemicals Ltd.Plant II, Mangalore, India

1997 2300 SSVB / SVF

Saudi Arabian Oil Co. (Saudi Aramco),Rabigh, Saudi Arabia

1997 11700 SSVB

Api Raffineria di Ancona SpA,Falconara, Italy

1996 750 STG Upgrade

El-Nasr Petroleum Co.,El-Suez, Egypt

1996 3250 SSVB

Staatsolie Maatschappij Suriname NV,Wanica District, Suriname

1995 390 SSVB

Kirishinefteorgsintez,Kirishi, Russia

1994 5700 SSVB / SVF

Mitteldeutsche Erdoel-Raffinerie GmbH,Leuna, Germany

1993 4200 SSVB / SVF







--

LicenseeYear

LicensedCapacity,


Hovensa LLC,St. Croix. Virgin Islands, United States

1992 6400 SSVB / SVF

Mangalore Refinery & Petrochemicals Ltd.Plant I, Mangalore, India

1992 2300 SSVB / SVF

Pilipinas Shell Petroleum Corp.,Tabangao, Phillipines

1992 3300 SVF / STG

Rayong Refinery Company,Map Ta Phut, Rayong, Thailand

1992 3200 SSVB

National Iranian Oil Co.,Abadan, Iran

1991 5050 SSVB

Petroleum Co. of Trinidad & Tobago Ltd.,Pointe-a-Pierre, Trinidad

1991 5000 SSVB / SVF

Petrogal,Sines, Portugal

1990 4400 SSVB

National Iranian Oil Co.,Bandar Abbas, Iran

1988 5250 SSVB

Saras SpA,Sarroch, Sardinia, Italy

1988 7200 SSVB / VF

Turkish Petroleum Refineries Corp(Tüpras),Izmir, Turkey

1988 3100 SSVB

ExxonMobil Refining & Supply Co.,Naples, Italy

1985 1420 SSVB

Raffineria di Roma SpA,Rome, Italy

1985 4700 SSVB

Sinopec,Guangzhou, China

1985 3000 SSVB







--

LicenseeYear

LicensedCapacity,


Sinopec,Yanshan, China

1985 3000 SSVB

Elf France,Donges, France

1984 4800 SSVB

ExxonMobil Refining & Supply Co.,Frontignan, France

1984 2000 SSVB

MOL Hungarian Oil & Gas Co.,Szazhalombatta, Hungary

1984 2100 SSVB

Belgian Refining Corp. NV,Antwerp, Belgium

1983 3650 SSVB

Hellenic Petroleum SA,Aspropyrgos, Greece

1983 3800 SSVB

Honam Oil Ref. Co. Ltd.,South-Korea

1983 5300 SSVB

Perac,Pakistan

1983 2000 SSVB

Saudi Aramco-Shell (Sasref), Al-Jubail,Saudi Arabia

1983 4000 SSVB

Total SpA,Aquila, Italy

1983 3000 SSVB

Cie. de Raffinage et de Distribution TotalFrance,Gonfreville l'Orcher, France

1982 3200 SSVB / VF

Premcor Refining Group,United States

1982 3200 SSVB

Repsol YPF SA,Cartagena Murcia, Spain

1982 4800 SSVB







--

LicenseeYear

LicensedCapacity,


Shell Nederland Raffinaderij - TGI-a,Pernis, The Netherlands


Chevron-Texaco Corp.,Pembroke, United Kingdom

1981 4400 SSVB

Motor Oil (Hellas) Corinth Refineries SA,Aghii Theodori, Greece

1981 3000 SSVB

PCK Raffinerie GmbH,Schwedt, Germany

1981 4800 SSVB / SVF

Petro-Canada Products Ltd.,Montreal, Canada

1981 2200 SSVB

Repsol YPF SA,Tarragona, Spain

1981 4800 SSVB

Ste. Tunisienne Industries des Raffinage,Bizerte, Tunisia

1981 3640 SSVB

Thai Oil Ref. Co. Ltd,Sriracha, Thailand

1981 3000 SSVB / VF

Deutsche BP AG,Hamburg, Germany

1980 2400 SSVB

Deutsche Shell AG,Godorf, Germany

1980 1300 SSVB / VF

ERN,Neustadt, Germany

1980 2400 SSVB

Gulf,Sarni, Italy

1980 2100 SSVB

Kuwait National Petroleum Co.,Kuwait

1980 5600 SSVB







--

LicenseeYear

LicensedCapacity,


Refineria Isla Curazao SA,Emmastad, Curacao, Netherlands Antilles

1980 7000 SSVB Upgrade

Shell Canada Ltd.,Montreal, Canada

1980 2700 SSVB

Shell Canada Ltd.,Sarnia, Canada

1980 570 SSVB

Shell Nederland Raffinaderij - TGI-b,Pernis, The Netherlands


Singapore Petroleum Co. Ltd.,Pulau Merlimau, Singapore

1980 4800 SSVB

Thai Oil Ref. Co. Ltd,Thailand

1980 4500 SSVB

Total SpA,Aquila, Italy

1980 4000 SSVB

Cie. de Raffinage et de Distribution TotalFrance,La Méde, France

1979 4400 SSVB / VF

Lindsey Oil Refinery,Killingholme South Humberside, UnitedKingdom

1979 4500 SSVB

OMV AG,Schwechat, Austria

1979 3000 SSVB

Orion Refining Corp., Good Hope [Norco],Louisiana, United States

1979 19000 SSVB

Shell Eastern Petroleum (Pte.) Ltd.,Pulau Bukom, Singapore


SIBP,Antwerp, Belgium

1979 7300 SSVB







--

LicenseeYear

LicensedCapacity,


BP PLC,Lavera, France

1978 3500 SSVB / SVF

DEA Mineraloel AG,Wesseling, Germany

1978 3300 SSVB

Deutsche Shell AG,Harburg, Germany

1978 2500 SSVB / VF

Api Raffineria di Ancona SpA,Falconara, Italy

1977 2000 SSVB / VF

Fortum Oil and Gas Oy,Naantali, Finland

1977 1200 SSVB

Netherlands Refining Co.,Rotterdam, The Netherlands

1977 6600 SSVB

Ste. des Petroles Shell,Berre l'Etang, France

1977 4100 SSVB

Fortum Oil and Gas Oy,Porvoo, Finland

1976 4800 SSVB

Petroplus,Cressier, Switzerland

1976 1900 SVF / STG

Shell and BP PLC Petroleum RefineriesPty. Ltd. (SAPREF),Durban, South-Africa

1976 4600 SSVB / SVF

Cie. Rhenane de Raffinage,Reichstett - Vendenheim, France

1974 3000 SVF / STG

Shell,Gothenburg, Sweden

1974 4650 STG

Shell,Teesport, United Kingdom

1974 2000 STG







--

LicenseeYear

LicensedCapacity,


Shell Eastern Petroleum (Pte.) Ltd.,Pulau Bukom, Singapore

1973 5500 SVF / STG

Shell Cia. Argentina de Petroleo SA,Buenos Aires, Argentina

1970 1500 SSVB

Phillips 66, Wood River. IL,United States

1968 2900 SSVB

Shell, Sofa,Norway

1968 4000 STG


1966 2500 SVF / STG

AS Dansk Shell,Fredericia, Denmark

1964 4400 VF / STG Upgrade

Ste. des Petroles Shell,Petit Couronne, France

1963 2000 SSVB / SVF


1961 2700 SVF / STG

Paraguana Refining Center - RV1,Cardon/Judibana, Falcon, Venezuela

1958 5000 SSVB


1958 5000 SSVB


1958 4500 SSVB

Russian Refining Technology Conference 2001 Page 1 of 24

ABB Lummus Global

Opportunities for optimization of refineries using

Thermal Conversion technologies

by

F. Hollander, A. Keukens, M. van EsABB Lummus Global, The Hague, The Netherlands

&

B. DouwesShell Global Solutions, Amsterdam, The Netherlands

0. Summary

Thermal Conversion technologies remain dominant technologies in residueupgrading in most parts of the world. Their simple basic process layout hasbeen refined in recent years to remain a reliable and economic technologywith distinct advantages over more complex and high investment conversiontechnologies. Also for the near future Thermal Conversion processes areexpected to play a key role in refinery operations relying on furtherimprovements in technology, operation and unit management. Russia andthe CIS Republics depend heavily on fuel oil and heavy distillates. Notsurprisingly, demand for state-of-the-art Thermal Conversion technologies isgrowing, both in revamp situations and new applications. Shell, with ABBLummus Global as authorized licensor, has developed innovative ThermalConversion technologies that play a leading role in today’s residue upgradingmarket, but also in the conversion of heavy and vacuum gasoils. Thatleading role of Shell and ABB has resulted in more than 80 operating unitsworldwide. Based on the latest projects, most of them in Russia and the CISRepublics, different case studies - including revamping of existing crude orvisbreaking units, addition of the Shell Vacuum Flasher and grass-roots ShellSoaker Visbreaking, Shell Thermal Gasoil Process and Shell Deep ThermalConversion units - are presented showing the “opportunities for optimizationof refineries using Thermal Conversion technologies”.


ABB Lummus Global

1. Introduction

The Shell Soaker Visbreaker process has a long and successful history. Therelationship between Shell and ABB Lummus Global in the field ofvisbreaking was first established in the early sixties, with the construction ofa number of conventional coil visbreakers. By the early 1970’s, the ShellSoaker Visbreaker concept was sufficiently developed to be commerciallyapplied. The process was licensed for the first time in 1977. At this time,Shell appointed ABB as the authorized licensor for the process and tobecome more deeply involved in servicing this technology. The Shell SoakerVisbreaker Technology has subsequently become one of the more widelyapplied refining processes. The number of licensed units totals 90 with a totalinstalled capacity of about 400,000 tons per day, approximating to more than70 percent of the world’s visbreaking capacity in the last decade.

Visbreaking has shown to be a robust technology in the dynamic refiningmarket. Although other competitive processes have been developed, ShellSoaker Visbreaking remains of major importance in the upgrading of heavyresidues. The installation of new visbreaking plants nowadays continues atthe same pace as in the 1980’s. This success is based on the fundamentalstrengths of the process. It remains a low cost, high conversion, long runlength process that is very flexible with regard to feedstock and operationalchanges while producing valuable light products and stable fuel oil.

Over the years continued implementation of improvements in the ShellSoaker Visbreaker process, have resulted in designs geared to highreliability and performance. Shell’s continuous effort in the development ofnew applications has resulted in new thermal conversion technologies suchas vacuum flashing technology, deep thermal cracking and thermal gasoilconversion. These new technologies are emerging, well-proven and willwiden the choice of refiners to optimize their refinery with ThermalConversion solutions.

This paper describes in brief four different Shell Thermal Conversiontechnologies licensed by ABB as authorized licensor based on the latestprojects in Russia and the CIS Republics, the Czech Republic, Germany,India and Saudi Arabia. Different case studies - including revamping ofexisting crude, vacuum or visbreaking units, addition of the Shell VacuumFlasher and grass-roots Shell Soaker Visbreaking, Shell Thermal GasoilProcess and Shell Deep Thermal Conversion units - are presented.

Other technologies from the Shell Thermal Conversion portfolio, are ShellHigh Pressure Distillate Conversion and technologies that are developed to(co-)process slops and asphalts. These technologies are aimed to meet thefuture gasoil endpoint and environmental specifications.


ABB Lummus Global

2. Technologies

2.1 Shell Soaker Visbreaking Technology (SSVB)

The Shell Soaker Visbreaking (SSVB) Technology has been developed byShell in the late seventies. The technology has since evolved further and hasbeen successfully licensed and applied in over 80 units worldwide. ShellSoaker Visbreakers account for over 70% of the total Visbreaking capacitybuilt or being built in the last 10 years. This makes it the most successful andwidely applied residue upgrading technology in the world.

The main objective of the Shell Soaker Visbreaker is to reduce the viscosityof Atmospheric or Vacuum Residue, which significantly reduces the need ofcutterstock for blending to commercial fuel oil. Besides the viscosityreduction, valuable products like LPG, Naphtha and Gasoil are produced.Other possible feedstocks that can be used are asphalt and slops.

By shifting the majority of the cracking process from the heater coils (as inall-coil designs) to the Soaker drum, prolonged residence time is achieved,allowing a lower cracking temperature. In combination with Shell’s patentedSoaker internals this assures better selectivity, longer runlength, lowerenergy demand and lower capital investment.

The main characteristics of the technology are:§ Typical feedstock is Vacuum Residue§ Large feed stock flexibility§ Compact unit comprising a residue conversion and a fractionation

section§ Application of a soaking vessel with proprietary internals§ The amount and the viscosity of the residue (and hence of the fuel oil)

are reduced, typically fuel oil production reductions of 25 wt.% can beachieved

The benefits of the Shell Soaker Visbreaking technology compared to theconventional furnace (coil) cracking technology can be summarized asfollows:§ Longer run length and higher on stream time§ Improved selectivity towards Gasoil§ Reduced fuel and power consumption§ Lower capital expenditure§ Improved operability due to use of pressure (Soaker) and temperature

(heater) as control variables

Figure 2.1 below presents the Shell Soaker Visbreaker process. Preheatedresidue feedstock is charged to the Visbreaker heater (1) and from there tothe Soaker (2). The conversion takes place in both the heater and theSoaker. The operating temperature and pressure are controlled such as toreach the desired conversion level and/or unit capacity. The cracked feed is


ABB Lummus Global

then charged to an atmospheric fractionator (3) to produce the desiredproducts like gas, LPG, naphtha, kero, gasoil and cracked residue.

x

Charge

gas

gasoil

naphtha

visbroken residue

steam

1

3

2

steam

Figure 2.1 Simplified Flow Scheme of Shell Soaker Visbreaker Unit

Revamping of existing crude and (coil) Visbreaker units is possible, ABB hasrevamped succesfully several existing coil visbreakers and crude units intoShell Soaker Visbreaker. The Russian market shows great potential with agrowing number of crude and visbreaking units nearing the end of theireconomic life span. With an investment of between 30% and 60% of a newgrass roots unit, revamping towards a Shell Soaker Visbreaker is a fast andlow cost solution to reduce the amount of cutterstock required for theproduction of fuel oil.

2.1.1 Case 1: Grass-roots Shell Soaker Visbreaker Unit

Client: KirishinefteorgsintezProject: Basic Design and Engineering / Detailed EngineeringTime: 1994 / 2001

Background:

The project involved the implementation of a new Shell Soaker VisbreakerUnit, consisting of the following elements:

• Feed heating and reaction• Fractionation and residue stripping• Gasoil stripping• Naphtha stabilization• Off-gas amine absorbe


ABB Lummus Global

Currently, the project is in the detailed engineering phase. Expected start-upis in 2003.

Feedstock:

The Shell Soaker Visbreaker Unit will process a blend of vacuum residuesfrom West Siberian and Ukhta origin. The unit capacity is 5789 MT/SD.

Yields and Properties:

The following product yields can be obtained. Main product properties arealso shown:

FeedstocksVacuum Residue 241.2 t/h

Viscosity 1941 cSt @ 100°C

ProductsOffgas (C4

-) Yield 1.8 wt%

H2S content < 0.005 wt% (Note 1)

C5+ content 8.2 wt%

Stabilized Naphtha (C5 – 173°C) Yield 4.4 wt%

RVP < 0.7 kg/cm2a

Visbreaker Residue (173°C+) Yield 93.8 wt%


Flashpoint > 65 °CTable 2.1 Yields and Properties of Shell Soaker Visbreaker products

Note 1: After Amine treatment.

Blending details:

The final fuel oil product will fulfil the Mazut M100 specifications of whichviscosity is the governing parameter. In this example, blending with typicalLight Cycle Oil (LCO) from a Fluid Catalytic Cracker is shown.

In the Table 2.2, the required amount of LCO is given for the situation withand without a Shell Soaker Visbreaker Unit.

Saving 60 t/h on LCO and producing more than 70 t/h less Fuel Oil clearlyunderlines the benefits of a Shell Soaker Visbreaker Unit.


ABB Lummus Global

LCO Requirements Fuel OilProduction

Vacuum Residue (w/o SSVB) 90 t/h (27.2 % of total) 331 t/h

Visbreaker Residue (with SSVB) 31 t/h (13.5 % of total) 257 t/h

Table 2.2 Cutterstock requirements and fuel oil production comparison

2.1.2 Case 2: Revamp to Shell Soaker Visbreaker Unit

Client: LUKOIL PermnefteorgsyntezProject: Basic Design and Engineering PackageTime: 2001

Background:

The project involves the revamp of an existing thermal cracker into a ShellSoaker Visbreaker Unit. The main objective of this project is to re-use asmuch of the existing equipment as possible. The unit includes the followingsections:

• Feed heating and reaction• Fractionation and residue stripping• Gasoil stripping• Naphtha stabilization

Feedstock:

While the current feedstock consists of residual material of varying natureand various refinery slops, the revamped unit will process a mixture ofvacuum residue originating from West Siberian and Local Perm crudes. Thedesign unit capacity is 2800 MT/SD.

Process Scheme:

The current process scheme with respect to the separation and fractionationof the heater effluent is given in the Figure 2.2 below. The Rectifier operatesat elevated pressure compared to the Stripper, which operates at nearatmospheric conditions. Steam is used for stripping of the residue.


ABB Lummus Global

CURRENT OPERATION

RE

CT

IFIE

R

ST

RIP

PE

R

SE

PA

RA

TO

R

RE

AC

TO

R

HEATER EFFLUENT

HEAVY GASOIL

NAPHTHA

NAPHTHA

LIGHT GASOIL

RESIDUE

Figure 2.2: Current situation

In an attempt to redeuce investment cost, by re-using as much of the existingequipment (specifically the columns) as possible, the following flow schemewas developed and proposed to the client:

PROPOSED OPERATION

RE

CTI

FIE

R

SE

PA

RA

TO

R

SO

AK

ER

HEATER EFFLUENT

NAPHTHA / OFFGAS

GASOIL

ST

RIP

PE

R

GA

SO

IL S

TRIP

PE

R

RESIDUE

INDICATES REUSED EQUIPMENT

Figure 2.3 Proposed new scheme

As can be seen from Figure 2.3, the Separator, Stripper and Rectifier will bere-used. As advanced construction materials are required for such high


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temperature equipment, re-using these columns is of primary importance forreducing the required investment. A new stripper is foreseen for qualitycontrol of the Visbreaker Gasoil.

The complete fractionation section is operating near atmospheric pressure inthe new situation. This highly improves the quality of separation betweenResidue, Gasoil and Naphtha. The Naphtha is further processed in aNaphtha Stabilizer (the existing column and associated equipment will bere-used for that purpose) producing Stabilized Naphtha, LPG and Fuel Gas.The Fuel Gas is treated to remove H2S in a central amine absorber unit.


With the proposed scheme, the following product yields can be obtained.Main product properties are also shown:

FeedstocksVacuum Residue 118 t/h


Coker Naphtha (note 1) 20 t/h

ProductsOffgas (C2

-) Yield 1.4 wt%

C5+ content < 5 wt%

LPG (C3/C4) Yield 1.0 wt%

C5+ content < 3 wt%

Stabilized Naphtha (C5 – 165 °C) Yield 17.3 wt%

C4- content < 1 wt%

Gasoil (165 – 350 °C) Yield 10.0 wt%

Flashpoint > 65°C

Visbreaker Residue (350 °C+) Yield 70.3 wt%

Viscosity 260 cSt @ 100°CTable 2.3 Yields and properties of Case 2

Note 1: Unstabilized Naphtha from the Delayed Coker Unit is stabilizedtogether with the Visbreaker Naphtha in the common NaphthaStabilization section.

Blending details:

The final fuel oil product will fulfil the Mazut M100 specifications of whichviscosity is the governing parameter. In this example, blending with typical


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Light Cycle Oil (LCO) from a Fluid Catalytic Cracker with and without a ShellSoaker Visbreaker Unit is shown.

In Table 2.4, the required amount of LCO and the total fuel oil production ispresented.

LCO Requirements Fuel OilProduction

Vacuum Residue (w/o SSVB) 30 t/h (20% of total) 148 t/h

Visbreaker Residue (with SSVB) 6.4 t/h (5.5% of total) 117 t/h Note 1

Table 2.4 Cutterstock requirements and fuel oil production comparison,Case 2

Note 1: Includes gasoil produced by unit.

From Table 2.4, the benefits of a Shell Soaker Visbreaker Unit can be seen.

2.2 Shell Vacuum Flasher (VF) Technology

To maximize the recovery of distillates from the Thermal Conversioneffluents Shell has developed proprietary Flashing Technology forintegration/combination with Thermal Conversion Units. Shell has developeda proprietary transfer line that maximizes the recovery of distillates andavoids entrainment of residue. The other draw back of open art flashingtechnology in thermal conversion service is the short run length of thevacuum columns due to severe coking and fouling. Due to the application ofproprietary column internals the fouling and coking has been reducedsubstantially resulting in vacuum flasher run lengths up to several years.

The main characteristics of the technology are listed below.§ Proprietary transfer line and column internals§ No residue entrainment§ Long run length§ High Flashed Distillate Yield§ No feed heater§ Effective cutpoints up to 550°C can be achieved§ Production of Light Flashed Distillate to Gasoil specification§ Can be applied to all Thermal Conversion Technologies except Delayed

Coking§ Can be added to existing thermal conversion units

The main benefits of Shell Thermal Conversion Flashing Technologycompared to open art flashing technology can be summarized as follows:§ Longer run length and higher on stream time


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§ Higher distillate yields§ Lower capital expenditure§ Additional Gasoil recovery

Figure 2.4 below presents the Shell Soaker Visbreaker process including theShell Vacuum Flasher. Similar to the SSVB, preheated residue feedstock ischarged to the Visbreaker heater (1) and from there to the Soaker (2). Thecracked feed is then charged to an atmospheric fractionator (3). The crackedresidue is fed into the Shell Vacuum Flasher (4) which separates the lightvacuum gasoil (LVGO) and heavy vacuum gasoil (HVGO) from the vacuumflashed cracked residue (VFCR).

Charge

gas

gasoil

naphtha

vacuum flashedcracked residue

steam

1

3

2

steam

LVGO

HVGO4

Figure 2.4 Shell Soaker Visbreaker with Shell Vacuum Flasher A calculation has been done for a typical Visbreaker unit with a capacity of4000 MT/SD, processing Middle East Vacuum residue with a viscosity of3900 cSt at 100°C. Figure 2.5 presents the difference in blending of aVisbreaker unit and a Visbreaker unit with Vacuum Flasher.

The Shell Vacuum Flasher is an option for refineries were Heavy or VacuumGasoil can be processed in a Hydrocracker or an FCC unit or Shell ThermalDistillate Conversion unit. Visbroken Vacuum Gasoil, by its parrafinic nature,is a good feedstock for FCC’s.


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VB

GAS

VB RES.

NAPHTHA

GASOIL

VFVB TAR

GASOIL

FUELOIL

FEED4000

76

164

460

3200

2680

1404

4544

HGO +VGO 620

VB

GAS

VB RES.

NAPHTHA

GASOIL

GASOIL

FUELOIL

FEED4000

76

164

460

3200

1164

4924

Figure 2.5 Blending example

The Shell Vacuum Flasher can be built in a modular way and added next tothe visbreaker plot. Figure 2.6 shows a 3D-model of a visbreaker unitoriginally built by Shell and to which a Shell Vacuum Flasher was added lateron. The Shell Vacuum Flasher section has been highlighted.

Figure 2.6 Modular design of Shell Vacuum Flasher Add-on


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2.2.1 Case 3: Shell Soaker Visbreaker Unit with Vacuum Flasher

Client: Indian clientProject: Basic Design and Engineering PackageTime: 2000

Background:

The project involved the basic design of a new Shell Soaker Visbreaker Unitincluding Shell Vacuum Flasher Technology, consisting of the followingelements:

• Feed heating and reaction• Fractionation and residue stripping• Overhead product compression (recontacting) section• Gasoil stripping• Naphtha stabilization• Vacuum Flasher

Currently, the project is in the EPC phase. Expected start-up is in 2002.

Feedstock:

The Shell Soaker Visbreaker and Vacuum Flasher Unit will process afeedstock comprising of 85% Vacuum Residue and 15% PDA pitchoriginating from a 50:50 Arab mix crude. The unit capacity is 3600 MT/SD.


Table 2.6 shows the product yields and main properties that will be obtainedin this unit.

Light and Heavy Vacuum Gasoils are used as feed to the Hydrocracker. TheVacuum Flashed Cracked Residue is blended to meet refinery fuel oilspecifications.


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Viscosity 7,251 cSt @ 100°C

ProductsOffgas (C4

-) Yield 2.0 wt%

H2S content 11.1 wt%

Stabilized Naphtha (C5–165°C) Yield 4.1 wt%

RVP < 0.7 kg/cm2a

Visbreaker Gasoil (165–350°C) Yield 11.2 wt%

Flashpoint 60 °C

Light Vacuum Gasoil (350–420°C) Yield 1.8 wt%

C7-insolubles < 0.2 wt%

Heavy Vacuum Gasoil (420–520°C) Yield 10.0 wt%

C7-insolubles < 0.2 wt%

Vacuum Flashed Cracked Residue (520°C+) Yield 70.9 wt%Viscosity 36,100 cSt @ 100°C

Table 2.5 Yields and properties of Case 3

2.2.2 Case 4: Shell Vacuum Flasher added to existing SSVB

Client: Shell HarburgProject: by ShellTime: 1979

Background:

The project involved the addition of a Shell Vacuum Flasher to an existingShell Soaker Visbreaker Unit including, consisting of the following elements:

• Vacuum Flasher

The revamped plant was started-up in 1981.

Feedstock:

The Shell Soaker Visbreaker and Vacuum Flasher Unit process a mix ofDeutsche Roh Oel and Tia Juana Pesado vacuum residue. The unit capacityis 2500 MT/SD.


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The following product yields can be obtained. Main product properties arealso shown:



ProductsOffgas (C4

-) Yield 2.8 wt%


RVP < 0.7 kg/cm2a


Flashpoint 60 °C

Vacuum Gasoil (365–530°C) Yield 13.0 wt%

C7-insolubles < 0.2 wt%Vacuum Flashed Cracked Residue (530°C+)

Yield 65.2 wt%Viscosity 1,400 cSt @ 100°C


The Vacuum Flashed Cracked Residue is blended to meet European fuel oilspecifications.

2.3 Shell Thermal Gasoil Process (STGP)

As highlighted in Section 2.2, by implementation of a vacuum flasher in theShell Soaker Visbreaker Process, considerable amounts of valuable vacuumdistillate can be recovered from the Visbroken residue. The recoveredvacuum distillate can be further processed in a conversion unit, like forinstance a Hydrocracker (HCU) or a Fluid Catalytic Cracker (FCC).

In refineries with no vacuum distillation unit, or in refineries withfully loadedHCU or FCC, an interesting solution is to convert the recovered vacuumdistillate in an integrated recycle thermal cracker heater system. Thecombination of a Shell Soaker Visbreaker for residue conversion and aseparate thermal conversion heater system for distillate conversion is calledthe Shell Thermal Gasoil Process (STGP). This technology was originallydeveloped in the sixties as an alternative for conversion of atmosphericresidue by FCC and HCU, and has since then been continuously improvedand developed further. Shell currently operates nine (8) such units.


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Description

Although there can be very significant differences with respect to choice offeedstock and the recovery of different products, most units applying theShell Thermal Gasoil Process follow the same concept, which is shown inFigure 2.7.

Charge

gas

gasoil

vacuum flashedcracked residue

steam

1

3

2

naphtha

steam4

6

5

Figure 2.7 Simplified Flow Scheme of Shell Thermal Gasoil Process

The preferred feedstock for the Shell Thermal Gasoil Process is atmosphericresidue, although vacuum residue can be used as well. The preheatedfeedstock is charged to the visbreaker heater (1) and from there to thesoaker (2). The conversion takes place in both the heater and the soaker.The operating temperature and pressure are controlled such as to reach thedesired conversion level and/or unit capacity. The cracked feed is thencharged hot to a cyclone (3) to separate the majority of the residue from thevaluable distillate products. The cyclone overheads are routed to theatmospheric fractionator (4) to produce the products like gas, naphtha,gasoil, heavy distillate and a residue. Cyclone bottoms and fractionatorbottoms are routed to a vacuum flasher (5) together. In this vacuum flasher,vacuum distillate is recovered from the residue. The temperature andpressure in the flashzone determine the cutpoint between the distillate andresidue. The recovered heavy and vacuum distillates from the fractionatorand the vacuum flasher are converted in the distillate cracking heater (6) atelevated pressure. Conversion levels, defined here as 165 - 350°C TBPmaterial on feed, can be as high as 30 - 40 wt%. To fully convert thedistillate, the unconverted material is recycled via the atmosphericfractionator and vacuum flasher. Consequently, the distillate furnace feedconsists partly of fresh feed and partly of recycled material.


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Benefits

The benefits of the Shell Thermal Gasoil Process compared to otherconversion technologies (Fluid Catalytic Cracking and Hydrocracking) can besummarized as follows:

§ Due to the highly integrated compact two stage thermal conversion unitdesign, comprising of a residue and a recycle distillate conversionsection, a combined fractionation and vacuum flashing section,substantial lower capital expenditure is required.

§ In a STGP large feedstock flexibility is possible, ranging fromatmospheric residue to vacuum residue, due to the nature of theprocess. In contrast to FCC and HCU technologies, which are limited intheir feedstock flexibility.

§ Complete conversion of the waxy distillate fraction, although a slightlylower conversion is achieved on the overall conversion compared to FCCand HCU technologies; the only products are gas, naphtha, gasoil andvacuum residue, typically 55-60 wt% of the atmospheric residue isupgraded to gasoil minus products.

§ No up-front vacuum distillation unit is required, as the majority of thevacuum gasoil in the atmospheric residue can be recovered in thevacuum flasher.

2.3.1 Case 5: Shell Thermal Gasoil Process

Client: Saudi ClientProject: by ShellTime: 1994/2000

Background:

The project involved the installation of a new Shell Thermal Gasoil unitintegrated with a gasturbine for power production. The unit consists of thefollowing elements:

• Integrated heat recovery and feed heating and reaction• Cyclone• Fractionation and residue stripping• Vacuum Flasher• Gasturbine

Successful Start-up of the unit took place in 2000.


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Feedstock:

The Shell Thermal Gasoil Unit processes a mix of atmospheric and vacuumresidue from Arab Light Crude. The unit capacity is 5,250 MT/SD.


Table 2.7 shows the product yields and properties that are obtained.



ProductsOffgas (C4

-) Yield 2.3 wt%


RVP < 0.7 kg/cm2a


Flashpoint 35 °CVacuum Flashed Cracked Residue (520°C+)

Yield 65.2 wt%Viscosity 900 cSt @ 100°C


About two thirds of the Visbreaker Gasoil is blended with the VFCR to makeEuropean spec fuel oil. The remainder is sent to the refienry gasoil pool.

2.3.2 Opportunities for Russian refineries

The main objective of the Shell Thermal Gasoil Process is the reduction ofthe viscosity of the residue feedstock while maximizing the production ofgasoil by thermally cracking the recovered heavy and vacuum distillates. Forhydroskimming refineries, i.e. refineries without upgrading potential of theatmospheric residue or in refineries withfully loaded HCU or FCC, this optionhas some very interesting features.

A phased approach can be applied to this unit. Initially only the residueupgrading part, i.e. the Shell Soaker Visbreaker part, will be installed, withsome pre-investment for the next step. In the next step the vacuum flasherand recycle distillate conversion heater are incorporated. Not only is theinitial investment lower, also a gradual reduction in fuel oil production andassociated gasoil production increase, will be achieved. This is certainly veryinteresting for refineries producing for markets where there is still a vastdemand for fuel oil, like the Russian market.


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Additionally the installation of a Shell Thermal Gasoil Process will eliminatethe requirement of installation of a vacuum distillation unit and upgradingfacilities for the produced vacuum gasoil, like a fluid catalytic cracker or ahydrocracker. Both of these units require huge investments (over 100 millionUS$), while the investment required for a Shell Thermal Gasoil Process willbe substantially lower. This will facilitate an easier financial closure of aproject.

For refineries already converting atmospheric residue in a visbreaker,implementation of the Shell Thermal Gasoil Technology is a low cost optionto reduce fuel oil production and increase production of valuable distillateproducts. A revamp of a coil type visbreaker unit to a STGP Unit wouldrequire installation of a soaker, cyclone, vacuum flasher and a recycledistillate cracking heater. Also some modifications to the feed preheat andthe atmospheric fractionator and its overhead system, due to the changes inyield, need to be implemented.

Based on aboves STGP, Shell has developed Shell's High PressureDistillate Conversion Process, to convert heavy tails of gasoils. With 80%conversion of the 330°C - 370 °C (heavy) gasoil fraction into lighter materials(< 330 °C), this technology enables refiners to meet tighter future gasoilspecifications.

2.3.3 Case 6: Comparison of SSVB and STGP

Client: Russian ClientProject: Feasibility studyTime: 2001

Background:

Hydroskimming refineries and refineries that process atmospheric, vacuumor a combination of atmospheric and vacuum residues in thermal crackingunits or exisiting visbreakers can benefit clearly from the Shell ThermalGasoil Process.

The example below is a study for a Russian refiner, processing Ukhta crude,considering to revamp an existing crude unit into a Shell Soaker Visbreaker.Comparison of the SSVB and STGP technologies indicates the possibilitieswhen choosing for the latter.

While both technologies produces stable on-spec Mazut M100 without therequirement of additional cutterstock, the Shell Thermal Gasoil Processproduces 350 MT/SD of high cetane gasoil that, after treatment, is anoutstanding component in the gasoil blending pool.


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Feedstock:

Comparison is made on the basis of Ukhta crude.


Feedstock Shell SoakerVisbreaker

Shell Thermal GasoilProcess

Mix of Atmospheric and Vacuum Residue 2400 MTD 2400 MTD

Viscosity 188 cSt @ 100°C 188 cSt @ 100°C

ProductsOffgas (C4

-) Yield 2.0 wt% 4.4 wt%

C5+ content < 5 wt% < 5 wt%

Stabilized Naphtha (C5 -165°C) yield 4.1 wt% 10.3 wt%

C4- content < 1 wt% < 1 wt%

Gasoil (165 – 350 °C) Yield 12.6 wt% 37.9 wt%

Flashpoint > 65°C > 65°C

Visbreaker Residue (350°C+) Yield 81.3 wt% -


Visbreaker Residue (520°C+) Yield - 47.4 wt%

Viscosity 3,900 cSt @ 100°CTable 2.8 Yields and properties of Case 6

After blending the Visbroken Residue with Visbroken Gasoil followingproducts remain:

Gasoil Production(net)

Fuel OilProduction (M100)

Shell Soaker Visbreaker 50 MTD 2205 MTD

Shell Thermal Gasoil Process 410 MTD 1638 MTD

Table 2.9 Gasoil and fuel oil production comparison, Case 6

2.4 Shell Deep Thermal Conversion Technology

The latest development by Shell in the area of Thermal Conversion is theShell Deep Thermal Conversion Technology. Due to the increase in non-fueloil outlets of thermally cracked residues new opportunities have arisen for


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thermal conversion. Shell has been able to improve the design and operationof the unit such that high conversion levels can be achieved whilemaintaining an acceptable unit run length.

This technology closes the gap between visbreaking and delayed coking(Figure 2.8). It realizes most of the delayed coking upgrading while avoidingthe drawbacks of solids handling. The residual product of Shell DeepThermal Conversion remains liquid and stable and is referred to as ‘liquidcoke’. Liquid coke can no longer be blended into a stable fuel oil and isprocessed directly in gasifiers (in power production or Partial Oxidation units)or is used as refinery fuel.

Thermal Conversion yield patterns

0

10

20

30

40

50

60

70

C4-MINUS C5-350°C 350-520°C VFCR/COKE

Fraction

Yie

ld, w

t%

Visbreaking + VF Deep Thermal Conversion DTC Delayed Coking

Figure 2.8 Closing the gap between Visbreaking and Delayed Coking

The main characteristics of the technology are listed below:§ Can be applied to both Shell Soaker Visbreaking as well as Shell

Thermal Gasoil units§ Typically 45-60 wt% of Vacuum Residue is converted to distillate

products§ Revamp of an existing unit is possible§ Liquid residual product§ Includes both design and operational know how

The main benefits of Shell Deep Thermal Conversion technology comparedto traditional Thermal Conversion technology can be summarized as follows:§ Substantially higher conversion§ Competitive run length and on-stream time


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§ Higher distillate yields from Vacuum Flasher§ Lower capital expenditure§ Improved operability due to use of pressure and temperature as control

variables

On the other side the main benefits of Shell Deep Thermal Conversiontechnology compared to delayed coking technology can be summarised asfollows:§ Higher quality products (needing less hydrotreating)§ Higher selectivity to gasoil§ Substantially lower capital expenditure§ No solids handling

Figure 2.9 below presents the Shell Deep Thermal Conversion process.Preheated short residue is charged to the heater (1) and from there to thesoaker (2), where the deep conversion takes place. The conversion ismaximized by controlling the operating temperature and pressure. Thecracked feed is then charged to an atmospheric fractionator (3) to producethe desired products like gas, LPG, naphtha and gasoil. The fractionatorbottoms are subsequently routed to a vacuum flasher (4), which recoversadditional gasoil and waxy distillate. The residual liquid coke is routed forfurther processing depending on the outlet.

x

Charge

gas

gasoil

waxydistillate

liquid coke

steam

1

3

2

x

x

naphtha

steam

4

Figure 2.9 Shell Deep Thermal Conversion

The Shell Deep Thermal Conversion can also be combined with the ShellThermal Gasoil Process. Similar to STGP, an additional furnace will convertthe heavy distillates into gasoil.


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2.4.1 Case 7: Deep Thermal Conversion

Client: CRC Litvinov, Czech RepublicProject: BDEP, EPC, Start-upTime: 1997-1999

Background:

The project involved the basic design, EPC and start-up of a new Shell DeepThermal Conversion Unit including Shell Vacuum Flasher Technology, withthe possibility to operate in Visbreaking and Deep Thermal Conversionmode. The unit consists of the following elements:

• Feed heating and reaction• Fractionation and residue stripping• Overhead product compression (recontacting) section• Gasoil stripping• Vacuum Flasher

Successful Start-up took place in 1999.

Feedstock:

The Shell Deep Thermal Conversion Unit processes a mixture of blackdistillate and vacuum residues originating from a Ural crude. The unitcapacity is 2500 MT/SD.


Table 2.10 presents the product yields and main properties of this unitrunning in SDTC mode.

When running in the SDTC mode, all vacuum distillates are sent to the FCCunit; the VFCR is sent to the POX.

In SSVB mode conversion of the feed is significantly less severe, enablingthe unit to produce commercial fuel oil after blending with the vacuumdistillates and a small amount of cutterstock.

This unit demonstrates the maturity of the Shell Thermal Conversiontechnologies, as it maximizes yields while maintaining a remarkable flexibilitytoward the need of the client.


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ProductsOffgas (C4

-) Yield 3.3 wt%

C5+ content < 12.0 wt%

Unstabilized Naphtha (C5–165°C) Yield 7.6 wt%

RVP < 0.7 kg/cm2a


Flashpoint 60 °C

VB Vacuum Gasoil (370–420°C) Yield 1.3 wt%

CCR < 0.8 wt%

Heavy Vacuum Distillate (420–520°C) Yield 14.7 wt%

CCR < 0.8 wt%

Vacuum Flashed Cracked Residue (VFCR) (520°C+) Yield 56.8 wt%Viscosity 36,100 cSt @ 100°C


2.4.2 Link to Russian market

Implementation of an IGCC is a high investment that can only be justified inrefineries that can consume all the power produced or in liberalized powermarkets where refiners can export their excess production to the public grid.Still, even without an IGCC, Shell Deep Thermal Conversion is an interestingsolution for refiners having an outlet for the residual product of this process.Russian and other refineries alike, depending on the crude, especially whennot too heavy, can use the residue of SDTC economically as refinery fuel, forthe production of carbon black or in cement kilns.

Another outlet can be as fuel for neighbouring power plants. With a typicalheating value 40,000 kJ/kg, the only real constraint is maximum viscosity thatcan be handled by the burners. Currently, burners are able to handleviscosities up to 300 cSt.

3. Economy

Shell Thermal Conversion Technologies are, in general, low cost solutionswith very short payback times (normally in the order of one year). Of course,this all depends on feedstock, configuration and prices for products. The


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table below presents a (rough) comparison of the TIC for four differenttechnologies. This comparison is based upon a 3,000 MT/SD unit processingAtmospheric and/or Vacuum Residue from a typical Ural crude.

SSVB SSVB+VF STGP SDTC

Feed VR VR AR/VR VR

Typical TIC MM US$ 20.6 25.5 28.3 28.2

Table 2.11 Estimated TIC for Shell Thermal Conversion Technologies

The estimated TIC’s are based on new brown field unit includingengineering, equipment, instrumentation, piping, structures, buildings, etc.The estimated TIC’s are CIS based and have an accuracy of 30%. Excludedfrom the estimated TIC’s are other processing units for treatment, etc, utilitysystems and license fees.

4. Conclusion

With the improvements and wider applicability of Shell's present ThermalConversion technologies good opportunities exist to process cheaper crudeoils and/or cheaper feedstocks (such as asphalt) and meeting future gasoilspecifications while maintaining the well-proven robustness. Shell'scontinuous development in Thermal Conversion technologies provide higherdistillate yields, while increasing unit reliability and operability. The co-operation of ABB and Shell guarantee the best possible provision of provenexperience and know-how in the Thermal Conversion area.

Depending on refinery layout, crude, product slate and environmentallegislation there is a Shell Thermal Conversion option for every refinery.

Overview

Lower cracking temperatures and longerresidence time

Use of soaker drum with special internalsminimizes backmixing

Smaller furnace

Lower furnace pressure drop

AdvantagesProcess Features

The Shell Soaker Visbreaking process is ideallysuited for the reduction of heavy fuel oil productvia resid viscosity reduction and maximum pro-duction of distillates. Typical applications includeatmospheric and vacuum resids and solventdeasphalter pitch. The Shell Soaker Visbreakingprocess is jointly licensed by Shell and ABB.

ABB and Shell have extensive technical andcommercial experience in soaker visbreaking, whichresults in highly efficient and reliable units. Over80 Shell Soaker Visbreaking units have been builtor converted from coil visbreakers and crude units.Over 70% of the total visbreaking capacity builtduring the last 10 years was based on this Shelltechnology. It offers demonstrated advantagesthat include significantly lower fuel requirements,increased heater run length, and higher conver-sion operation with better viscosity reduction.

The technology provides refiners with themeans to conserve valuable cutter stock while stillproducing high quality, stable fuel oil. This con-servation of valuable cutter stock, combined withfuel savings derived from the technology, offersan overall cost advantage that leads to projectpayouts of one to two years.

Shell’s visbreaking process can be tailored tomeet the refiners’ specific needs. A vacuum flashercan be added to obtain increased distillate recov-ery. Incorporating two-stage cracking in combina-tion with a vacuum flasher will increase conversionand distillate recovery.

With typically 20% of the vacuum resid feedconverted to distillate and lighter products, ShellSoaker Visbreaking is one of the lowest costconversion process options.

Client Benefits

Selective cracking to distillate product■ less sensitive to operational and feedstockfluctuations ■ better process control ■ longerrun lengths and less down time

Higher conversion for the same fuel oilstability ■ more distillate production■ less cutter stock usage

Lower investment cost ■ less waste heatrecovery equipment ■ lower fuel consumption

Less power consumption

PerformanceCharacteristics

0.4-0.7% Higher Conversion (165°C-)

1-2% More Distillate Yield (350°C-)

30-35% Lower Heat Duty15% Lower Investment Cost

Shell Soaker Visbreaking

1 of 2

Shell Soaker Visbreaking

ProcessDescription

Resid feed is pumped through the preheat ex-changers before entering the visbreaker heater,where the resid is heated to the required crackingtemperature. The high efficiency heater is alsoutilized to superheat stripping steam. Heatereffluent is sent to the soaker drum where most ofthe thermal cracking and viscosity reduction takesplace under controlled conditions. Soaker drumeffluent is flashed and then quenched in thefractionator. Heat integration is maximized inorder to keep fuel consumption to a minimum.The flashed vapors can be fractionated into gas,gasoline, gasoil and visbreaker residue.

Process FlowDiagram

Liquid visbreaker residue is steam-stripped inthe bottom of the fractionator and pumped throughthe cooling circuit to battery limits. Visbreakergasoil, which is drawn off as a side stream, issteam-stripped, cooled and sent to battery limits.Alternately, the gasoil fraction can be includedwith the visbreaker effluent. It is also possible toobtain a heavy vacuum gasoil fraction by addinga vacuum flasher downstream of the fractionator.

Cutter stocks, such as light cycle oil or heavyatmospheric gasoil, may be added to the visbreakerresidue/gas oil mixture to meet the desired fuel oilspecification.

Stripper

AirCooler

FractionatorSoakerDrum

Heater

Fresh Feed

Residue

Gasoil

Gasoline

Gas

Steam

Steam

Reflux Drum

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Overview

Lower cracking temperatures and longer residencetime


Distillate cracking heater

Smaller visbreaker heater

Lower visbreaker heater pressure drop


ABB offers the Shell Thermal Gasoil process toupgrade atmospheric residue and waxy distillate.Originally developed in the 1960s, continued im-provement in the Shell-designed soaker drum andheater designs resulted in the present ThermalGasoil technology, a combination of three ma-ture, well-proven Shell technologies:■ Soaker Visbreaking■ Vacuum Flashing■ Thermal Cracking

Shell was the first to develop and employsoaker visbreaking technology. The soaker drum,with patented internals, achieves higher conver-sion and improved viscosity reduction comparedto other visbreaking technologies. Over 80 unitshave been designed and built worldwide.

The Shell Vacuum Flashing technology wasdeveloped to recover distillates from thermal

conversion residue. The specially designed trans-fer line and vacuum flasher internals maximizethe flashed distillate yield and quality, and assurea run-length comparable to that of the rest of theThermal Gasoil unit despite the severe foulingtendencies of the residue feed.

The design of the distillate Thermal Crackingheater is based on Shell’s experience and know-how in the field of thermal cracking in general.

ABB and Shell have extensive experience inthe design of thermal conversion processes. Withcontinual feedback from operating units, we areable to provide advanced designs and practicaladvice on operational matters. Shell’s ongoingresearch and development in thermal crackingtechnology and equipment design assures theavailability of the most up-to-date know-how inthis field.

Client Benefits

Selective cracking to distillate product ■ lesssensitive to operational and feedstock fluctuations■ better process control ■ longer run-lengths andless down time

Higher conversion for the same fuel oil stability■ more distillate production ■ less cutter stock usage

Maximum naphtha yield ■ maximum gasoil yield

Lower investment cost ■ less waste heat recoveryequipment ■ lower fuel consumption



Typical Feedstock Typical Product

Atmospheric residue ___________________ Middle East

Viscosity, cst @ 100°C _____________________________ 31

% wt on feed

Gas ___________________________________________________ 6.4

Gasoline ECP 165°C _____________________________ 12.9

Gasoil ECP 350°C ________________________________ 38.6

Residue ECP 520°C+ ____________________________ 42.1

Viscosity 165°C plus, cst @ 100°C _____________ 7.7

Shell Thermal Gasoil

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Shell Thermal Gasoil

ProcessDescription

Atmospheric residue is pumped through feed pre-heat exchangers, where the feed is heated againstcracked residue, to the visbreaker heater. Thefeed is heated to the required cracking tempera-ture and routed to the soaker where the majorityof the thermal cracking occurs under controlledconditions. The soaker effluent is routed to acyclone and the cyclone overheads are charged tothe flash zone of the atmospheric fractionator.

In the top section of the fractionator, thesoaker effluent is split into four fractions: heavygasoil, gasoil, naphtha and offgas. The gasoil istaken from the fractionator as a draw off, steam-stripped in a side stripper to improve the flashpoint, and sent to the battery limit. The overheadvapors are condensed in a two-stage condensingsystem: in the first stage, only the reflux is con-densed; in the second stage, the naphtha productis condensed. From the overhead system, the offgasand naphtha are sent to the battery limit.

Process FlowDiagram

Inside the fractionator, the liquid is quenchedto prevent further cracking and then steam-stripped. The hot fractionator bottoms, togetherwith the cyclone bottoms, are routed to thevacuum flasher where the vacuum gasoil (VGO)is recovered. The VGO is sent, together with theheavy gasoil from the atmospheric fractionator, toa distillate thermal cracking heater where it ispartly converted into lower boiling fractions. Theheater effluent is routed to the flash zone of theatmospheric fractionator. The unconverted heavygasoil is recovered in the fractionator and vacuumflasher and is recycled back to the distillatethermal cracking heater to maximize the gasoilyield.

The vacuum-flashed residue is cooled againstthe VGO and then by steam generation. Thecooled residue is sent to fuel oil blending where itis blended with gasoil product and/or other cutter-stocks to meet the specified fuel oil viscosity.

Naphtha

Gasoil

Heavy Gasoil

VGO

AtmosphericResidue

Offgas

Distillate ThermalCracking Heater

VisbreakerHeater

Soaker

Cyclone

Steam

AtmosphericFractionator Steam

Vacuum FlashedCracked Residue

VacuumFlasher



Overview

Lower cracking temperatures and longer residencetime


Smaller visbreaker heater

Lower visbreaker heater pressure drop

Deep Thermal Gasoil: Distillate cracking heater


The Shell Deep Thermal Conversion process fillsthe gap between visbreaking and coking. It wasdeveloped based on many years of experiencewith the Shell Soaker Visbreaking process. Theprocess yields a maximum of distillates by apply-ing deep thermal conversion of the vacuumresidue feed and by vacuum flashing of thecracked residue. High distillate yields are ob-tained while still producing a stable liquid re-sidual product, referred to as liquid coke. Theliquid coke, which is not suitable for blending tocommercial fuel, is used for specialty products,gasification and/or combustion, e.g. to generatepower and/or hydrogen.

The Shell Deep Thermal Gasoil process is acombination of the Shell Deep Thermal Conver-sion and the Shell Thermal Gasoil processes. Inthis alternative high conversion scheme, the heavy

gasoil (HGO) from the atmospheric fractionatorand the vacuum gasoil (VGO) from the vacuumflasher are cracked in a distillate thermal crackingheater into lower boiling point gasoil.

For more than 20 years, ABB has been anauthorized licensor for Shell Thermal Conversiontechnologies, which include Shell Deep ThermalConversion (SDTC), Shell Deep Thermal Gasoil(SDTG), Shell Thermal Gasoil Process (STGP),Shell Soaker Visbreaking (SSVB) and Shell VacuumFlashing (SVF). These technologies have beensuccessfully applied worldwide. ABB and Shell’sextensive experience includes almost 100 projectsand even more studies, and covers both new unitsand conversions of existing crude, vacuum and(soaker) visbreaking units into SDTC, SDTG,STGP and SSVB.

Client Benefits

Selective cracking to distillate product ■ lesssensitive to operational and feedstock fluctuations■ better process control ■ longer run-lengths andless down time

Higher conversion for the same fuel oil stability■ more distillate production ■ less cutter stock usage

Lower investment cost ■ less waste heat recoveryequipment ■ lower fuel consumption


Maximum naphtha yield ■ maximum gasoil yield


Typical Feedstock Typical Product

Vacuum residue ____________ Middle East

Viscosity, cst @ 100°C ________________ 770

Deep Thermal Deep ThermalProduct in % wt on feed Conversion Gasoil

Gas _________________________________________ 4.0 ________________ 4.0

Gasoline ECP 165°C ____________________ 8.0 ________________ 8.0

Gasoil ECP 350°C ______________________ 18.1 _______________ 40.6

Waxy distillate ECP 520°C+ __________ 22.5 __________________ –

Residue ECP 520°C+ __________________ 47.7 _______________ 47.4

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Shell Deep Thermal Conversion and Shell Deep Thermal Gasoil

Shell Deep Thermal Conversion and Shell Deep Thermal Gasoil

ProcessDescription

Deep Thermal Conversion: Preheated vacuumresidue is charged to the visbreaker heater andfrom there to the soaker, where the deep conver-sion takes place. The conversion is maximized bycontrolling the operating temperature and pres-sure. The soaker effluent is routed to a cycloneand the cyclone overheads are charged to the flashzone of the atmospheric fractionator to producethe desired products like gas, LPG, naphtha, keroand gasoil. The fractionator bottoms are routed to

Deep ThermalGasoil ProcessFlow Diagram

a vacuum flasher, which recovers additional gas-oil and vacuum gasoil (VGO). The residual liquidcoke is routed for further processing dependingon the end use.

Deep Thermal Gasoil: The heavy gasoil from theatmospheric fractionator and the VGO from thevacuum flasher are cracked in a distillate thermalcracking heater. The cracked distillates are routedto the fractionator.

Naphtha

Gasoil

Heavy Gasoil

VGO

VacuumResidue

Offgas

Distillate ThermalCracking Heater

VisbreakerHeater

Soaker

Cyclone

Steam

AtmosphericFractionator Steam

Liquid Coke

VacuumFlasher

Deep ThermalConversionProcess FlowDiagram

Naphtha

Gasoil

VGO

VacuumResidue

Offgas

VisbreakerHeater

SoakerCyclone

Steam

AtmosphericFractionator

Steam

Liquid Coke

VacuumFlasher



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