2015 Honeywell Users Group Europe, Middle East and · PDF file2015 Honeywell Users Group...

$: 2015 Honeywell Users Group Europe, Middle East and · PDF file2015 Honeywell Users Group Europe, Middle East and Africa ... (NGL) fractionation trains using a ... fractionation train$
2015 Honeywell Users Group

Europe, Middle East and Africa

Retrofitting of the natural gas liquid (NGL) fractionation trains using a

modified self-heat recuperative (MSHR) process to improve the overall

energy efficiency of gas processing plant (GPP)

Students: Ren Jie Lee, Shih Chiang Lim, Tze Mun Sam, Ying Ting Loo

Curtin University, Sarawak Malaysia

Supervisor: Dr Mesfin Getu Woldetensay

2 © 2015 Honeywell International All Rights Reserved

• Background

• Problem Statement

• Objectives & Scopes

• Methodology

• Results & Discussion

• Conclusion

• References

Content


• Natural gas is the major source of liquid

hydrocarbons product primarily used in

petrochemical industry and transportation sector.

• The composition of natural gas varies substantially

depending on its source.

• High quality natural gas and natural gas liquids (NGL)

possess clean fuel characteristic and it is the major

source of income among gas processors [1].

• The growing interest has allowed the energy market to

keep up with the accelerating trend where 64% growth

in demand is forecasted by 2030 [2].

Background


Background (cont.)

Natural gas and NGL shows promising production trend

Global Primary Energy Sources Comparison [1]


Background (cont.)

Demand for clean fuel is expected to rise over time

Natural Gas Production/Consumption Share of 2014 [3]

28%

5% 29%

17%

6% 15%

Production

28%

5% 30%

14%

3% 20%

Consumption

North America South and Central America Europe and Eurasia Middle East Africa


• The Gas Processing Plant separates natural gas liquid

(NGL) components, acid gases, and water from a gas-

producing well and it conditions these fluids for sale

or disposal [4].

• The purpose for further removing C2+ hydrocarbons: ‒ NGL fractions have higher economical value separately.

‒ Safety specification for delivery and combustion.

• The fractionation train consists of 3 main distillation

column namely Deethanizer, Depropanizer and

Debutanizer in PRU.

Background (cont.)


pretreatment unit (PTU)

acid gas removal unit

(AGRU)

condensate treatment unit

(CTU)

dehydration unit (DHU)

low temperature separation unit

(LTSU)

sales gas compression unit (SGCU)

propane refrigeration unit

(PRU)

propane recovery unit

(C3RU)

Background (cont.)

Natural Gas Processing Plant

product recovery

unit (PRU)


Product of GPP

Sales Gas

Ethane

Propane Butane

Condensate

Background (cont.)

Fuel for

vehicles

Plastic

pellets

Cooking

gas, LPG

Industries

application


There was less effort made in trying to improve

the energy efficiency of the product recovery unit

(PRU) of gas processing plant (GPP). The PRU which

consists of Deethanizer, Depropanizer and Debutanizer

fractionation train consumes a significant amount of

energy due to the large amount of utilities applied

during operation. Hence, there is a need to reduce the

energy consumption of these fractionation trains using

promising alternative retrofit design.

Problem Statement


Objectives

• To improve the PRU energy efficiency of gas processing

plant

• To explore different options of single column distillation to

achieve higher energy efficiency of gas processing plant

• To assess the economical feasibility of the gas processing

plant and thereby optimize the whole process.

Scope

• The project focuses on enhancement of GPP energy

efficiency and product recovery from each distillation

columns.

Objectives and Scope


Methodology

Base Case Stimulation

Base Case Optimization

Retrofit MSHR Simulation

Retrofit MSHR Optimization

Energy Integration

Economic Analysis


• According to Long and Lee [5], up to 73.43 − 83.48% of

the condenser and reboiler energy were saved with

the self-heat recuperation technology.

• It is also theoretically proven that MSHR provides the

highest annual operating cost saving, up to 67.19%

per annum amongst the others.

MSHR (Modified self-heat recuperative)

52.03%

53.49%

62.17%

67.19%

0 10 20 30 40 50 60 70

Annual Operating Cost Saving [5]

MSHR

(Heat exchangers

in parallel)

MSHR

(Heat exchangers

in series)

Self- heat

recuperative

column

Heat Pump


MSHR Concept

• To maximize heat recovery duty, feed stream is divided into two parallel stream.

• Vapor is compressed and condensed in column's reboiler.

• Top outlet stream exchanges heat with the feed stream and cooled further before divided into two stream. 1. recycled back into the column as reflux 2. another is the final top product

• As a result, all heat is recirculated in the process

without the need for external heat.


UniSim® – Conventional Gas Processing Plant

Base Case with fractionation train Deethanizer

Depropanizer

Debutanizer


UniSim® – Pre-Treatment Unit (PTU)


UniSim® – Condensate Treatment Unit (CTU)


UniSim® – Low Temperature Separation Unit (LTSU)


UniSim® – C3RU and SGCU

Propane Refrigeration Unit (C3RU)

Sales Gas Compression Unit (SGCU)


Retrofit – GPP with MSHR

Overall PFD of retrofits in UniSim® sub-flowsheets

39.7% energy saving

29.5% total energy saving

34.9% energy saving

15.4% energy saving


Retrofit I – Deethanizer

39.7% energy saving


Retrofit II – Depropanizer

15.4% energy saving


Retrofit III – Debutanizer

34.9% energy saving


Results and Discussion- Energy Saving

39.7% energy saving compared to base case

Base Case kW

Condenser 5607

Reboiler 7264

Total energy consumed 12871

MSHR kW

Compressor 4244

Cooler 3514


Total Savings 5113

Deethanizer


Results and Discussion- Energy Saving (cont.)


Base Case kW

Condenser 6436

Reboiler 5348


MSHR kW

Compressor 4665

Cooler 5305


Total Savings 1814

Depropanizer



Base Case kW

Condenser 3660

Reboiler 2506


MSHR kW

Compressor 1331

Cooler 2682


Total Savings 2153

Debutanizer

Results and Discussion- Energy Saving (cont.)


Energy Saving Analysis With MSHR

Total energy saved worth 30% from base case

Depropanizer Debutanizer Deethanizer

39.7% 34.9% 15.4%

Retrofit I Retrofit II Retrofit III


Sensitivity Analysis

$0,00

$200.000,00

$400.000,00

$600.000,00

$800.000,00

$1.000.000,00

$1.200.000,00

$1.400.000,00

$1.600.000,00

$1.800.000,00

$2.000.000,00

80 90 100 110 120

To

tal O

pe

rati

ng

Co

st,

$/y

r

Electricity price factor, $/(kW.a)

TOC vs Electricity price factor

Retrofit I

Retrofit II

Retrofit III


Optimization Result

Increase in profit after optimization

Optimization Base Case ($/yr) MSHR ($/yr)

Before 203,912,158 207,029,971

After 326,104,913 328,009,054


Economic Analysis

Analysis shows improved profit profile

Base Case ($/yr) MSHR ($/yr)

Total Operating Cost (TOC) 7,629,122.87 3,108,628.67

Total Capital Cost (TCC) 4,255,896.80 12,201,082.65

Total Annualized Cost (TAC) 11,885,019.67 15,309,711.31

Gross Profit 435,000,000 437,900,000

Net Profit 326,104,913 328,009,054

Payback Period (yr) 0.04 0.05


• The energy savings of Deethanizer, Depropanizer

and Debutanizer columns are 39.72 %, 15.39 %,

and 34.92 %

• Total annualized cost (TAC) for the base case and

MSHR retrofit are 12×106 $/year and 15×106

$/year.

• Payback periods for the MSHR retrofit is 0.05 year

Conclusion


1. Kidnay, A. J., W. R. Parrish, and D. G. McCartney. 2011. Fundamentals

of Natural Gas Processing. 2 ed. 0 vols: CRC Press.

2. BP Energy Outlook 2030. 2013. BP. Accessed on June 17,

http://www.bp.com/content/dam/bp/pdf/Energy-economics/Energy-

Outlook/BP_Energy_Outlook_Booklet_2013.pdf.

3. BP statistical Review of world energy June 2015. 2015. Accessed June

26, http://www.bp.com/en/global/corporate/about-bp/energy-

economics/statistical-review-of-world-energy.html.

4. Mokhatab, Saeid, and William A. Poe. 2012. "Chapter 4 Basic Concepts

of Natural Gas Recovery Plant." In Handbook of Natural Gas

Transmission and Processing (Second Edition), ed. Saeid

MokhatabWilliam A. Poe, 353-391. Boston: Gulf Professional

Publishing.

5. Long, Nguyen Van Duc and Moonyong Lee. 2013. A novel NGL (natural

gas liquid) recovery process based on self- heat recuperation. Energy,

57. 663-670.

References


Thank you.

No reproduction or use of this material may be made without Honeywell’s prior written permission.

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