Maguire Gravimetric Blending. Introduction Products & Software.
Refinery Products Blending
Transcript of Refinery Products Blending
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Refinery Products Blending
Tri TRUONG HUU
Tel: 0932 445 199
Mail: [email protected] Vung Tau, 2015
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About Instructor
Current job position:Lecturer - Researcher, Chemical Engineering - Oil and Gas
University of Science and Technology - The university of Da Nang
Studies:
- , - -
2008-2011: Doctor of Philosophy in Chemical Engineening - University of
Strasbourg - France;
2000-2001: Master of science in Petroleum Products and Motor, IFP - France;
1997: Engineer in Chemistry of Oil Refining and Petrochemistry, Hanoi
University of Technology.
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EMERGENCY EVACUATION INSTRUCTION
Whenever you hear the building alarm or are informed of ageneral building emergency:
Leave the building immediately, in an orderly fashion;
Do not use elevators;
Follow quickest evacuation route from where you are;
If the designated assembly point/area is unsafe or blocked due to
the emergency, proceed to the alternate assembly point;
Report to your Work Area Rep at the assembly point to be checked
off as having evacuated safely;
Specific safety requirements for TODAY.
Today: NO testing of fire alarm systems
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COURSE OUTLINE
Total duration: 1 day;
Lecture: 1 day;
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OUTLINE
1. Energy and environmental issues;
2. Classification of fuels;
3. Product specifications (TCVN system);
.
5. Fuel additives;
6. Petroleum Products blending;
7. Blending calculation and learner programming.
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COURSE OBJECTIVES
When you complete this module you will be able:
To grasp main characteristics of petroleum products and
their significance in regard to needs of end-users;
o grasp ma n spec ca ons o pe ro eum pro uc s ;
To grasp the general calculation in a refinery;
To grasp the blending calculation and the product blending
system.
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COURSE ASSESSMENT
Lecture:
The multiple-choice (knowledge based questions) section of
the test is scored based on the number of questions you
answered correctly;
Multi-choice test : uestions Passing grade: 80%;
No additional points are subtracted for questions answered
incorrectly;
Even if you are uncertain about the answer to a question, it is
better to guess than not to respond at all.
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INTRODUCTION
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Introduction
The worlds primary energy consumption (this value varies
depend on source).
Source : BP 2014
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Petroleum is one of the most important fuels derived fossil energysources;
Petroleum-based fuels have been used to power automotive
vehicles and industrial production for well over 100 years;
Introduction
A large part of energy consumption is in form of engine fuels;
Fuels for internal combustion engines produced from primarily
sources are composed ofcombustionable molecules;
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Different gas, liquid, and solid products are usable as engine
fuels.
These fuels are classified:
Crude oil based: Gasoline, diesel fuels, and any other gas and
Introduction
Non-crude oil based: Natural gas based fuels (compressed natural
gas (CNG))
Biofuels: methanol, ethanol, any other alcohols and different
mixtures of them; biodiesel; biogas oil (mixtures of iso- and n-paraffins from natural tryglicerides).
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Environmental issues
Introduction
C6H6
Sulfur compounds + Oxyen SOx acids
Soot
PM
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Introduction
European emission standards for light commercial vehicles 1305 kg, g/km
For
Diesel
For Gasoline
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Introduction
European emission standards
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Introduction
The path toward zero emissions
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Introduction
The progression toward zero emissions
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Introduction
The path toward zero emissions
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Introduction
EU gasoline specifications
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Introduction
EU gasoline specifications
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Introduction
European Gasoline specifications trends
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Introduction
World context:High RON,
Low sulfur content,
Low benzene content,
Limited aromatics content,
Limited olefins content,
No lead
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Introduction
World context:
High octane gasoline requirement:
RON = ... 90 92 95 98 ???
Why we need High octane gasoline ?
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Introduction
New gasoline specifications require: Maintaining a high octane number;
Meeting reduced sulfur content;
Meeting reduced Aromatics and Benzene
specifications;
Meeting reduced Olefines specifications.
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I
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t
r
od
u
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io
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Introduction
Typicaly gasoline pool
composition in EU
(before 2000)
Typicaly gasoline pool
composition in USA
(before 2000)
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The mechanism of the development of vehicles and fuels
Introduction
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Over the years, fuel specifications have evolved considerably to
meet the changing demands of engine manufacturers and
consumers;
Both engines and fuels have been improved due to
Introduction
New processes have been developed to convert maximum refinery
streams into useful fuels of acceptable quality at reasonable
refinery margins.
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Classification
o ue s
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Classification of fuels
The fuel industry categorizes the different types of fuels as follows:
Gasoline: A volatile mixture of liquid hydrocarbons generally
containing small amount of additives suitable for use as a fuel in a
spark - ignition internal combustion engine;
Unleaded gasoline: Any gasoline to which no lead have been
intentionally added and which contains not more than 0.013 gram
lead per liter (0.05 g lead/US gal);
E85 (E5) fuel:A blend of ethanol and hydrocarbons in gasolinewith 7585% (
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Classification of fuels
The fuel industry categorizes the different types of fuels as follows:
Racing gasoline:A special automotive gasoline that is typically
of lower volatility, has a narrower boiling range, a higher
antiknock index, and is free of significant amounts of oxygenates.
s es gne or use n rac ng ve c es, w c ave g
compression engines;
Liquified Petroleum gases: (LPG) Gas phase hydrocarbons,
mainly C3and in low quantity C4. Their quality is determined by
the country or regional standards.
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Classification of fuels
The fuel industry categorizes the different types of fuels as follows:
Compressed natural gas (CNG): Predominantly methane
compressed at high pressures suitable as fuel in internal
combustion engine;
Aviation turbine fuel A refined middle distillate suitable for use
as a fuel in an aviation gas turbine engine;
Diesel fuel A middle distillate from crude oil commonly used in
internal combustion engines where ignition occurs by pressure
and not by electric spark.
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Classification of fuels
The fuel industry categorizes the different types of fuels as follows:
Low or ultra-low sulfur diesel(ULSD): Diesel fuel with less
than 50 and 10 mg/kg respectively;
Biodiesel:A fuel based on mono-alkyl esters of long-chain fatty
acids derived from vegetable oils or animal fats. Biodiesel
containing diesel gas oil is a blend of mono-alkyl esters of long
chain fatty acids and diesel gas oil from petroleum. A term B100
is used to describe neat biodiesel used for heating, which does not
contain any mineral oil based diesel fuel.
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ProductASTM
SpecsDescription
Gasoline D4814Standard Specification for Automotive Spark Ignition
Engine Fuel
Jet D1655 Standard S ecification for Aviation Turbine Fuels
Product Specifications
Kerosene D3699 Standard Specification for Kerosene
Diesel D975 Standard Specification for Diesel Fuel Oils
Fuel Oil D396 Standard Specification for Fuel Oils
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NSRPs Specification of LPG
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NSRPs Specification of Gasoline
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NSRPs Specification of Gasoline
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NSRPs Specification of Kerosene
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NSRPs Specification of Diesel fuel
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NSRPs Specification of Diesel fuel
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NSRPs Specification of Jet A1
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NSRPs Specification of Jet A1
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NSRPs Specification of Jet A1
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Aviation Gasoline:BS EN 589:2004
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NSRPs Specification of Fuel Oil
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NSRPs Specification of Paraxylene
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NSRPs Specification of Benzene
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Product blending system
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Purpose of blending
The process units produce various product components and base
stocks, which must be combined or blended, sometimes with
suitable additives, to manufacture finished products;
These finished products are generally grouped into the broad
categories:
LPG;
Gasoline;
Kerosene, Jet fuel;
Diesel;
Fuel oil, and so forth.
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Purpose of blending
Increased operating flexibility and profits result when refinery
operations produce basic intermediate streams that can be
blended to produce a variety of on specification finished
products;
The objective of product blending is to allocate the available
blending components in such a way as to meet product
demands and specifications at the least cost and to produce
incremental products which maximize overall profit.
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Purpose of blending
Blending methods normally employed include:
Batch blending;
Partial in-line blending;
Continuous in line blendin .
Petroleum products are shipped in bulk using:
Pipelines;
Marine tankers;
Occasionally road or rail facilities.
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Batch blending
In batch blending, the componemts of a product are added
together in a tank, one by one or in partial combination;
The materials are mixed until a homologenous product is
obtained.
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Batch blending
Additives are added and
mixed thoroughtly
After laboratory analysis
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Batch blending
Jet Mixer
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Batch blending ismost adaptable to use in small refineries, in
which a limited variety of blends are to be produced.
In a refinery, the cost of extra blending tanks, pumps, and
related e ui ment ma not be as lar e as the cost of
Batch blending
instrumentation and equipment needed for in-line blending; and
for this reason, many large refineries continue to use the batch
blending system because of its ease and flexibility of its
operation.
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Partial in-line blending
Partial in-line blending is accomplished by adding together
product components simultaneously in a pipeline at approximately
the desired ratio without necessarily obtaining a finished
specification product;
Final adjustments and additions are required, based on laboratory
tests, to obtain the specification product;
In this case, the mixing is required only for final adjustment;
Additives are added as a batch into the blending header during
the final stages of the blend or final adjustment stage.
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Partial in-line blending
The required components are pumped simultaneously from each
base stock tank through the appropriate flow controller into a
blending header, so an individual pump is required for each
component.
The capacity of the pump must be established to permit
simultaneous pumping and delivery of one day's blend to product
tanks within a reasonable time (about 6 hours);
The quantity of each component of a blend must be proportioned
by the use of a flow meter and control valve.
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Partial in-line blending
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Partial in-line blending
Flow controllers are set to a predetermined rate and flow is
recorded;
Flow meters used for partial in-line blending need not be
extremely accurate (accuracy ranges of 5%)
Mixers are required in final storage tanks for correction of blends
by addition of components.
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Partial in-line blending
Partial in-line blending is suitable formoderate-sized refineries,
where the cost of blend tanks would be excessive and blending
time must be minimized.
Blending time is substantially reduced because of the following:
Simultaneous pumping of components instead of consecutive
pumping, as is the case in batch blending;
Reduction of overall mixing time;
Elimination of multiple gauging operations.
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Continuous in-line blending
In this way, all components of a product and all additives are
blended in a pipeline simultaneously,with such accuracythat,
at any given moment, the finished specification product may be
obtained directly from the line;
The accuracy and safeguards included in the system, so no
provision is necessary for reblending or correction of blends;
Various methods of controlling individual flow rates with
interlock provisions have been used to ensure delivery of only the
specified material.
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Continuous in-line blending
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Continuous in-line blending
An individual pump is required for each component, the quantity
of each component of a blend must be accurately delivered;
The recording flow meters and flow control valves used to
proportion components are similar to those used for partial in-line
blending, but a greater degree of accuracy is necessary (An
accuracy of 0.25% or better is expected);
To ensure continued accuracy of the blends under varying
operating conditions, the blending equipment is designed toprovide for adjustment of individual component flow in
proportion to total flow.
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Continuous in-line blending
Two types of blending controls are used to adjust component
flows to desired rates: a mechanical system or an electronic
system;
To ensure the accuracy of the blend,it is necessary to calibrate
meters frequently. One method of meter calibration is to remove
the meter from the system and replace it with a calibrated space
meter;
Continuous in-line blending is best for large refineries thatmake several grades of products.
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Continuous in-line blending
Advantages:
1. Reduced blending time.
2. Minimum finished product storage, since components are
stored and blended as required.
3. Increased blending accuracy with minimum "give away" on
quality.
4. Reduction in loss through weathering of the finished
product.
5. Minimum operating personne.
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Continuous in-line blending
Disadvantages:
1. When products are transferred directly to a pipeline or bulk
transport, a complete blender is required for each product,
which must be loaded simultaneously. For example, if a tanker is
,
blenders are necessary; otherwise, the advantage of reduced
product tankage cannot be realized.
2. There is extreme difficulty in correcting errors, if they occur
(the only possible errors are human errors).
3. High initial investment and high maintenance cost of instruments.
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Fuel additives
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Fuel additives
Additive is a chemical compound (substance) which is used in
small dosages in order to add or improve properties of virgin
fuels.
Conventionally, chemical compounds added in:
Hi h concentrations >1% called blendin com onents
Lower concentrations (
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Fuel additives
There are six reasons for using additives in fuels:
To improve handling properties and stability of the fuel;
To improve combustion properties of the fuel;
To reduce emissions from fuel combustion;
To provide engine protection and cleanliness;
To establish or enhance the brand image of the fuel;
To increase in the economic use of the fuel.
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Fuel additives
Motor engine gasoline additives and their functions:
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Fuel additives
Motor engine gasoline additives and their functions:
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Fuel additives
Additives for Gasoline Distribution Systems
Antioxidants
Metal deactivators
Antistatic agents
Corrosion inhibitors
Sediment reduction agents
Dyes
Dehazers
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Fuel additives
Additives for gasoline vehicle system
Antiknock additive (was tetra ethyl lead, which is now phased out)
Anti-valve seat recession additive (also phased out due to metallurgy
change in the engines)
Car uretor etergents gra ua y eing p ase out ue to t e
introduction of injectors)
Deposit control additives
Deposit modifiers
Friction modifiers
Lubricity improvers
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Fuel additives
Additives of diesel fuels and their functions :
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Fuel additives
Additives of diesel fuels and their functions :
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Fuel additives
Additives for Diesel Distribution System
Antifoam agents
Antistatic agents
Biocides
Corrosion inhibitors
Sediment reduction agents
Dyes
Demulsifiers
Flow improvers/wax crystal modifiers/wax dispersants Metal
deactivators
Markers to check origin
Stabilizers
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Fuel additives
Additives for Diesel Vehicle System
Cetane improvers
Combustion improvers
Deposit control additives
Injector detergents
Lubricity improvers
Friction modifiers
F l ddi i
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Fuel additives
Additives for gasoline and diesel distribution systems are used in
refineries to meet minimum fuel specifications at the optimum cost
without compromising on the yield of the products;
Fuel quality standards have undergone a ratcheting-up gradation
with progressive improvements in engine design and more
stringent environmental regulations;
These changes in fuel quality have involved:
Reductions in: S, Ar, benzene, PHA, olefins, and lead;
Improvements in ON, CN, oxidation stability, and storage stability.
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Gasoline blending
G li bl di
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Gasoline blengding
The purpose of blending is not only to ensure the specification
techniques but also the specification environments;
During the blending of gasolines not only the physical and
chemical properties of each blending component has to be
considered but also those contributions that may be harmful
material emissions;
Quality of combustion (structure each substance)?
Volatile organic compounds (RVP, Distillation cure)?
The formation of toxic compounds the exhaust gas (Ar, Olefin, S...)?
G li bl di
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Gasoline blengding
G li bl di
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The blending stocks for gasoline:
Cat.Naphtha (FCC naphta); Reformate (CR);
Alkylate;
Isomerate;
Full range Naphtha;
Typicaly gasoline pool composition in USA
Gasoline blengding
Naphta obtained from others
process: hydrocracking,
Visbreaking, Delayed coke ...
Butane;
Oxygenate gasoline: MTBE,
ETBE, ethnol...
Additives
G li bl di
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Gasoline blengding
Typicaly gasoline pool
composition in EU
(before 2000)
Typicaly gasoline pool
composition in USA
(before 2000)
G li bl di
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Gasoline blengding
The main source of the benzene content (ca. 80%) is the
reformate, but the benzene content of the C5-C6 fraction of the
coker process, as well as of LCN, LSR, and hydrocracking
gasolines, is also significant;
The quantity of reformate and LCN determines definitely the
other aromatic content (ca. 65%);
The olefin content depends definitely on the used quantity of
LCN (ca. 90%).
G li bl di
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Gasoline blengding
The olefin content depends definitely on the used quantity of
LCN (ca. 90%);
In many refineries, the polymer naphthas and naphthas from
variants of thermal cracking processes have different effects on the
olefin content.
The sulfur contentis determined by the fraction ofHCN.
Gasoline blengding
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Gasoline blengding
The main sources of the volatile organic compounds (VOC)in
gasolines aren-butane (ca.25%), ethanol (ca.12%), alkylate (ca.
8%), reformate (ca.15%), HCN (ca.5%), LCN (ca. 23%), and
coking C5-C6fraction (ca.1%).
The reformate and cat.naphthas favor the formation of nitrogen
oxides (reformate ca.21%; HCN: ca.40%; LCN: ca.30%; n-butane:
ca.5%; isomerate: ca. 4%; coking C5-C6 fraction: ca. 2%).
Gasoline blengding
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Gasoline blengding
The formation of toxic materials and their emission quantities
depend on mainly the proportions used of reformate and the
cat.naphthas (reformate ca. 60%; HCN ca.14%; LCN ca.16%; n-
butane: ca.5%; isomerate: ca. 2%; coking C5-C6fraction: ca.1%;
alkylate: ca. 2%).
Knocking phenomenon
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Knocking phenomenon
Knocking (also called knock, detonation) in spark-ignition
internal combustion engines occurs when combustion of the
fuel/air mixture in the cylinder starts off correctly in response to
ignition by the spark plug, but one or more pockets of air/fuel
m x ure exp o e ou s e e enve ope o e norma com us onfront;
When unburned fuel/air mixture beyond the boundary of the
flame front is subjected to a combination of heat and pressure
for a certain duration (beyond the delay period of the fuel used),
detonation may occur.
Knocking phenomenon
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Knocking phenomenon
Detonation is characterized by an instantaneous, explosive
ignition of at least one pocket of fuel/air mixture outside of the
flame front;
A local shockwave is created around each pocket and the
cylinder pressure may rise sharply beyond its design limits.
Engine knockNormal
combustion
Engine knock
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Engine knock
Engine knock is a soud that is made when the fuel igintes too
early inthe compression stoke;
Severe knock causes severe engine damage, such as:
Decreased thermal efficiency of
Increased the toxic compounds in
the exhaust gas;
Possibility of mechanical damage
to the engine.
Octane number (ON)
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Octane number (ON)
Octane number is defined as the percentage of iso-octane ina blend of iso-octane (2,2,4-trimethylpentane) and n-heptane,
which will give the same engine performance as could be
achieved by the actual fuel sample.
An engine runs with100% pure iso-octane, the power rating is
100% (knock free) and is defined as100 octane number;
An engine is run with 100% n-heptane, a straight chain
hydrocarbon, there will betremendous knockingin the engineand theoctane number is taken as zero;
Octane number (ON)
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Octane number (ON)
Octane number (ON)
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The ON of the gasoline sample, therefore, falls within 0 100;
The ON of a hydrocarbon is a function of its chemical
composition: Isoparaffins and aromatics have high octane
numbers while n-paraffins and olefins have low octane
Octane number (ON)
numbers;
Aromatic > olefin branched > iso-parafin > naphten
branched > olefin normal > naphten > n-parafin.
Octane number (ON)
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Octane number is a parameter defined to characterize
antiknock characteristic of a fuel (gasoline) for spark ignition
internal combustion engines;
Octane number is a measure of fuel's ability to resist auto-
Octane number (ON)
ignition during compression and prior to ignition;
Higheroctane number fuels havebetterengine performance.
Octane number (ON)
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Octane values is measured in a standard engine, developed by
Cooperative Fuel Research (CFR) engine.
Octane number (ON)
RON MON
Octane number (ON)
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RON correlates with low speed, mild driving conditions;
MON relates to high speed, high severity conditions;
Most gasolines have higher RON than MON, this difference is
called fuel sensitivit :S = RON MON;
Octane number (ON)
For fuels of same RON, high S gasoline has lower MON;
Antiknock Index =(RON + MON)/2.
RdON
RONR100(RON)
Octane number (ON)
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Gasoline Blend Stock Properties
Octane number (ON)
Octane number (ON)
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Blending octane and RVP of ethers and alcohols
Octane number (ON)
Volatility of engine gasolines
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The volatility characteristic of engine gasolines has a
fundamental influence on the performance of (4 stock) spark-
ignition engines.
Volatility is characterized generally by the gasolines Reid
Volatility of engine gasolines
vapor pressure and distillation curve. The vapor-liquid ratio is
often considered as well.
Vapor Pressure
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Vapor pressure or equilibrium vapor pressure is defined as the pressure
exerted by a vapor inthermodynamic equilibriumwith its condensedphases (solid or liquid) at a given temperature in a closed system;
Vapor Pressure
The equilibrium vapor pressure is
'
evaporation rate. It relates to the
tendency of particles to escape from
the liquid (or a solid);
A substance with a high vapor
pressure at normal temperatures is
often referred to as voliatile.
Reid Vapor Pressure
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In reality, vapor pressure is usually measured in a bomb Reid, result
obtained called vapor pressure Reid (RVP);
RVP is defined as the absolute vapour pressure exerted by a liquid at
100 F (37.8 C) as determined by the test method ASTM-D323;
Reid Vapor Pressure
4 V
V
Reid Vapor Pressure
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RVP should be concerned:
Warm-up vehicle;
Vapor lock;
Evaporation losses.
Reid Vapor Pressure
The RVPs for gasoline are generally between 350 and 1000
mbar, depend on seasons and country.
Distillation curve
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Gasoline is a mixture of more than 400 volatile and flammable liquid
HC ranging from 4 to 12 carbon atoms/molecule, the boiling range fallsin the range 30 - 215C;
st at o cu e
In the laboratory, Gasoline is
distilled at atmospheric pressure
method of distillation (ASTM
D86);
A sample of 100 mL is placed
in a standard distilling flask and
the vapour is condensed through acondenser, liquid is collected in a
graduated cylinder.
Distillation curve
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Initinal Boiling Point(IBP): The temperature at which the first drop
of distillate appears after commencement of distillation in the standardASTM laboratory apparatus;
Final Boiling Point(FBP): The maximum temperature observed on
the distillation thermometer when a standard ASTM distillation is
carrie out; After the IBP, distillation is continued and the temperature of the
vapour and the cumulative volume percent collected are
simultaneously reported (5 percent: T5, 10 percent: T10, 15 percent: T15, 20
percent : T20
and etc...);
A distillation curve plots temperature versus the amount of distillate
collected or inverse.
Distillation curve
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Typical results for an ASTM D86 distillation of a gasoline
FBP
Losses Residue
IBP
Distillation curve
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Distillation curve
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Distillation curve
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Gasoline volatility should be arrangedaccording to weather conditions -
particularly ambient Temperature
Distillation curve
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IBP, T10should be concerned:
Start up at cold temperatures;
Vapor lock;
Evaporation losses.
T50should be concerned the acceleration.
T90,FBP should be concerned:
Oil dilution;
Power;
Spark plug fouling;
Pollution.
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Jet Fuel blending
Jet Fuel blending
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Jet Fuel blending
The key product properties of Jet fuel are:
Freezing point
Smoke point
Sulfur content
Flash point
Plant layout of a refinery
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Plant layout of a refinery
Jet Fuel blending
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Smoke point
The smoke point is determined as the height of the flame (in
millimetres) produced by this oil in the wick of a stove or a lamp
without forming any smoke;
Jet Fuel blending
The smoke point for an oil varies widely depending on originand refinement;
The greater the smoke point, the better the burning quality;
Smoke point is related to the hydrocarbon type composition of
such fuels, a high smoke point indicates a fuel of low smoke
producing tendency.
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Smoke point
1. Tetrahydronaphtalen C10H12
2. Mezitilen (C6H3(CH3)3)
3. Aromatics extracted from
kerosene fraction
Jet ue b e d g
4. Kerosen fraction without
aromatics
5. Cetene, C16H32
6. Cetane, C16H34
12 34 56
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Smoke point
Higher amount of aromatics in a fuel causes a smoky
characteristic for the flame and energy loss due to thermal
radiation;
g
ure sooc ane as a re erence smo e po n o . mm,
whereas 60 vol % isooctane and 40 vol % toluene have a
reference smoke point of14.7 mm;
Jet Fuel blending
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Sulfur content
Sulfur content is of great importance when the oil to be burned
produces sulfur oxides that contaminate the suraoundings;
Hydrogen sulfide and mercaptans cause objectionable odors, and
g
both are corrosive;
Their presence can be detected by the Doctor test (ASTM D-484,
ASTM D-4952, IP 30);
The total sulfur content of burning oil should be low, less than
0.25% by weight (ASTM D-1266, IP 107).
Jet Fuel blending
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Flash point
The flash point is the lowest temperature at which a liquid gives
off enough vapor to ignite when an ignition source is present;
The flash point of a petroleum product is the lowest temperature at
g
w ic it can vaporize to orm an ignita e mixture in air; at t e as
point, the vapor may cease to burn when the source of ignition is
removed;
For safety considerations, the flash point of kerosene is in excess of
38C, to prevent the inclusion of highly inflammable volatile fractions
in kerosene distillates.
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During flight, the temperature of the fuel in the aircraft tank
decreases lead to form solid hydrocarbon crystals, which restrict
the flow of fuel in the fuel system of the aircraft (clog filters);
Freezing point is the temperature at which the hydrocarbon
g
.
Test method ASTM D2386:
Freezing point of Jet A1
should be around -50o
C
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Diesel blending
Diesel blending
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g
Diesel blending is simpler than gasoline blending because the
limitations are fewer.
The key product properties are:
Cetane number;
Sulfur content (in some countries);
Specific gravity;
Aromatics (PHA?).
Diesel blending : Sulfur content
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Total sulfur content varies considerably in petroleum products.
Control of sulfur content is particularly important for petroleum
products that are to be burned in engine, heating applicances or
lamps.
Sul hur in diesel fuel can cause combustion chamber de osits,
g
exhaust system corrosion, and wear on pistons, rings and
cylinders;
Sulfur is measured on the basis of both quantity and potential
corrosivity;
The measurement of potential corrosivity can be determined by
means of a copper strip procedure.
Diesel blending : Sulfur content
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Sulfur content
Experimental result :
[S]=0,06% wt PM, soot : 2,1%*.
S =0 85%wt PM soot :5 8% *.
g
[S]=2,9% wt PM, soot : 12,2% *.
* deposited on piston and segment
Diesel blending : Sulfur content
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Sulfur content
Diesel blending : Cetane number
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Cetane number (CN) is a measure of the ignition delay of a diesel
fuel, the shorter of the ignition delay, the higher is its cetanenumber and inverse;
The cetane number of a diesel fuel is defined as the percentage of
cetane, arbitrarily given a cetane number of 100 (short ignition
delay), in a blend with alphamethyl-naphthaline given a cetane
number of 0 (long ignition delay), which is equivalent in ignition
quality to that of the test fuel.
CN = 100 CN = 0
C16H34
C11H10
Diesel blending : Cetane number
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The importance of cetane number is very evident.
As low CN usually causes an ignition delay in the engine, this
delay causes starting difficulties andengine knock;
Poor fuel economy;
Loss of ower;
Sometimes engine damage
White smoke and odor at start-up on colder days.
As low CN, combustion is violent, noisier, and less efficient
with a high level of exhaust emissions;
White exhaust smoke is made up of fuel vapors and aldehydes
created by incomplete engine combustion.
Diesel blending : Cetane number
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As high CN tend to:
Reduce combustion noise; Increase engine efficiency;
Increase power output;
Start easier, especially at low temperatures;
Reduce exhaust smoke; Reduce exhaust odor.
To assure acceptable cold weather performance,
CN required: 45 55
CN of diesel fuels can be improved by adding additives such as
2-ethyl-hexyl nitrate or other types of alkyl nitrates.
Diesel blending : Cetane number
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The calculated cetane index is a useful tool for estimating the
ASTM cetane number where a test engine is not available for its
determination or where the quantity of the sample is too small for
use in a test engine;
also developed.
ASTM D 976
: Density at 15o
C, g/mL; T50: Mid-boiling temperature,
oC.
CI = 454.74 1641.416 + 777.742 0.554(T50) + 97.083(log T50)2
Diesel blending : Cetane number
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CI = 454.74 1641.416 + 777.742 0.554(T50) + 97.083(log T50)2
Diesel blending : Cetane number
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ASTM D 976
CI = 45.2 + 0.0892T10N+ (0.131 + 0.901B)T50N+ (0.523 0.420B)T90N+ 0.00049(T
210N T
290N) + 107B + 60B
2
Where:
: Density at 15oC, g/mL;
T10N= T10-215,o
C; T50N= T50-260,
oC;
T90N= T90-310,oC;
B = e(-3.5DN)- 1;
DN = 0.85.
The calculated cetane index is particularly applicable to straight
run fuels, catalytically cracked stocks, and their blends.
Diesel blending : Cetane number
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CI can also measure from different parameters of the fuel, is
termed its diesel index (DI) or aniline point (PA) (ASTM D-611,
IP 2)
CI = PA 15.5; with PA: aniline point C
or
CI = 0.72 DI + 10;
where
100
)(API.PDI A
F
Diesel blending : Specific gravity
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SGis defined as the ratio of the weight of a given volume of oil
to the weight of the same volume of water at a given temperature;
SG is of limited usefulness as a direct measure of diesel fuel
quality;
consumption of an engine;
MinimumSG:this limit is necessary to obtain sufficient maximum
power for engine (flow controlled by regulating volume);
MaximumSG:this value is necessary to avoid smoke formation at
full load.
Diesel blending
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CI versus density of component produced by different technologies.
Diesel blending
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The sulphur and aromatic content range of different gasoil streams.
Diesel
blending
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g
Management and
control of motor
Diesel
blending
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g
Blend Optimization
and Supervisory
Diesel blending
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The main components of the blending technology package are the
following:
Interface for monthly linear programmed refinery models for
middle period recipes
Timing system for optimalizing future products and blending
orders
Online multivariate control and optimalization system for
feedback from control equipment to enable inline certificationand transport of products.
Diesel blending
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The controlled blending of fuels assures consistent profits for the
refineries, and the application of suitably admixtured products
having favorable hydrocarbon compositions means numerous
advantages for the users as well:
Smooth performance of vehicles;
More efficient fuel use;
Lower maintenance needs, longer engine life, lower
maintenance cost.
Diesel blending
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Smooth performance of vehicles
Easy cold start
Smooth idle
Good combustion
Optimal track behavior (no vibration, engine stop, etc.)
Excellent acceleration
Low noise pollution.
Diesel blending
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More efficient fuel use:
Reduction of fuel consumption
Reduction of exhaust gas
Emission exhaust as with more referable com osition.
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BLENDING CALCULATION
Blending calculation
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The main purpose of product blending is to find the best way of
mixingdifferent intermediate products available from the refinery and
some additives in order to adjust the product specifications;
Product qualities arepredicted through correlations that depend on
e quan es an e proper es o e en e componen s;
The final quality of the finished products is always checked by
laboratorytests before market distribution.
Gasolines are tested for ON, RVP and Distillation curve;
Jet fuel is tested for Freezing point and smoke point;
Gas oils are tested for DI, pour point and viscosity.
Blending calculation
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The desired property blend of the blended product may be
determined using the following mixing blend rule:
Piis the value of the property of component i
qiis :
Mass;
Volume; Molar flow rate.
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Additive properties:
Specific gravity; Boiling point;
Sulphur content;
Etc...
Properties are not additives: RON
Viscosity;
Flash temperature;
Pour point;
Aniline point;
RVP;
Cloud point.
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Reid Vapor Pressure is not an additive property. Therefore,
RVP blending indices are used.
xviis the volume fraction of component i.
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Flash Point is not an additive property. Therefore, flash point
blending indices are used.
where :
xvi is the volume fraction of component i;
BIFPiis the flash point index of component i.
FPi is the flash point temperature of component i, in K;
The best value of x is 0.06.
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Another relation to estimate the flash point blending index is
based on the flash point experimental data.
where : FPi is the flash point temperature of component i, in oF;
The flash point blending index is blended based on wt% of
components.
Blending calculation
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The pour point is the lowest temperature at which oil can be
stored and still capable of flowing or pouring, when it is cooled
without stirring under standard cooling conditions.
Pour point is not an additive property. Therefore, flash point
blending indices are used.
where :
xviis the volume fraction of component i;
PPi is the pour point of component i, in oR.
Blending calculation
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Cloud point is the lowest temperature at which oil becomes
cloudy and the first particles of wax crystals are observed asthe oil is cooled gradually under standard conditions.
Cloud point is not an additive property. Therefore, flash point
.
where :
xvi is the volume fraction of component i;
BICPiis the cloud point blending index of component i; CPi is the cloud point temperature of component i, in K;
The value of x is 0.05.
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Cloud point is the lowest temperature at which oil becomes
cloudy and the first particles of wax crystals are observed as theoil is cooled gradually under standard conditions.
Cloud point is not an additive property. Therefore, flash point
.
where :
xvi is the volume fraction of component i;
BICPiis the cloud point blending index of component i; CPi is the cloud point temperature of component i, in K;
The value of x is 0.05.
Blending calculation
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Aniline pointis not an additive property. Therefore, aniline point
blending indices are used.
where : xvi is the volume fraction of component i;
BIAPiis the aniline point index of component i;
APi is the aniline point of component i, in oC.
Blending calculation
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Specific gravity is an additive property and can be blended
linearly on a volume basis.
The specific gravity of a blend is estimated using the mixing
rule:
where :
xviis the volume fraction of component i.
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The smoke pointis the maximum flame height in millimetre at
which the oil burns without smoking when tested at standardspecified conditions.
where : SPBlendis the blend smoke point in mm;
APBlendis the aniline point;
SGBlendis the specific gravity of the blend.
API is not an additive property, and it does not blend linearly.
Therefore, API is converted to specific gravity, which can be blended
linearly.
Blending calculation
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Viscosity is not an additive property; therefore, viscosity
blending indices are used to determine the viscosity of theblended products.
A number of correlations and tables are available for evaluating
.
where :
xviis the volume fraction of component i;
BIvisi is the viscosity index of component i.
Blending calculation
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Octane number:If the octane number of a blend is calculated by
the linear addition of an octane number for each component, thefollowing equation can be obtained.
Where:xviis the volume fraction of component i, and ONi is the
octane number of component i.
Many alternative methods have been proposed for estimating the
octane number of gasoline blends since the simple mixing
rule needs minor corrections.
Blending calculation
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Octane number:The following octane index correlations depend
on the octane number range as follows.
Blending calculation
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Octane number:The octane number index for a blend can
be determined using the following equation:
ere:xvi s e vo ume rac on o componen , an s
the octane number index of component i that can be determined
from above equations.
Products blending at BSR
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Characteristics of components used to blend
Products blending at BSR
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Blending schematic
Products blending at BSR
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Blending schematic
Products blending
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Blending schematic
Products blending at BSR
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Products blending at BSR
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Results of products blending
Products blending at BSR
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Results of products blending
Products blending at BSR
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Results of products blending
Products blending at BSR
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Blending schematic
Bl di h ti
Products blending
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Blending schematic
Products blending at BSR
l f d bl di
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Results of products blending
Products blending at BSR
R l f d bl di
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Results of products blending
Bl di h i
Products blending
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Blending schematic
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Linear Programming
What is Linear Programming
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Terminology
Objective Function function z to be maximized;
Feasible Vector set of values x1, x2,,xN that satisfies all
constraints;
Optimal Feasible Vector feasible vector that maximizes theobjective function.
Solutions
Will tend to be in the corners of where the constraints meet
May not have a solution because of incompatible constraints or
area unbounded towards the optimum.
What is Linear Programming
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LP is the most widely applied method for optimising many
diverse applications, including refineries and chemical plants;
The application of LP has been successfully applied for selecting
the best set of variables when a large number of interrelated
choices exist;
A typical example is in a large oil refinery in which the stream
flow rates are very large, and a small improvement per unit of
product is multiplied by a very large number.
What is Linear Programming
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This is done to obtain a significant increase in profit for the refinery;
Optimisation means the action of finding the best solution within the
given constraints and flexibilities;
LP is a mathematical technique for finding the maximum value of
some equation subject to stated linear constraints;
Refinery optimisation using an LP model has been proven to bring
economic gains higher than unit-specific simulation models or advance
process control techniques;
Once all the data is configured, the model is updated with the variable
data.
What is Linear Programming
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The required variable data includes the following: Crude oil or
any other raw material prices with minimum and maximum
availability:
Selling prices with minimum and maximum demands for the
refinery products;
Available process unit capacities;
Available inventory stocks with minimum and maximum storage
limits;
Quality specifications, etc,
What is Linear Programming
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Word programming used here in the sense of planning
For N independent variables (that can be zero or positive)
maximize
Subject to M additional constraints (all bn positive)
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Thank you for
your attention