Retrofit of distillation columns in a methanol plant

Yaşar Demirel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Through its 'Column Targeting Tools' the Aspen plus simulator performs the 'Thermal Analysis' for rigorous column (RadFrac) calculations and produce Column Grand Composite Curves (CGCC) and exergy loss profiles. The CGCC displays the net enthalpies for the actual and ideal operations at each stage, and the cold and hot heat utility requirements, while the exergy loss profiles indicate the level of irreversibility at each stage including the condenser and reboiler. Therefore, the thermal analysis can identify the targets for restructuring and modifications, and may be helpful in suggesting retrofits. Some of the retrofits consist of feed conditioning (preheating or precooling), feed splitting, reflux adjustments, and adding side condensers and reboilers. These retrofits target a practical near minimum thermodynamic loss and suggest modifications for existing distillation columns by increasing the efficiency in energy utilization. This study uses the CGGC and the exergy loss profiles to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a methanol plant. Effectiveness of the retrofits is assessed by means of thermodynamics optimum and economics. The methanol plant is based on steam reforming and utilizes two distillation columns to purify the methanol in its separation section. The first column operates with 51 stages, has a side heat stream to the last stage, a partial condenser at the top and a side condenser at stage 2, and no reboiler. The second column operates with 95 stages, has a side heat stream to stage 95, a total condenser, and high reflux ratio. For the first column, the retrofits consisting of a feed preheating and a second side condenser at stage 4 have reduced the total exergy loss by 21.5%. For the second column, the retrofits of two side reboilers at stages 87 and 92 have reduced the total exergy loss by 41.3%. After the retrofits, the thermodynamic efficiency has increased to 55.4% from 50.6% for the first column, while it has increased to 6.7% from 4.0% for the second. The suggested retrofits have reduced the exergy losses and hence the cost of energy considerably, and proved to be more profitable despite the increases fixed capital costs of the distillation columns of the methanol plant.

Original languageEnglish (US)
Title of host publicationAIChE100 - 2008 AIChE Annual Meeting, Conference Proceedings
StatePublished - Dec 1 2008
Event2008 AIChE Annual Meeting, AIChE 100 - Philadelphia, PA, United States
Duration: Nov 16 2008Nov 21 2008

Publication series

NameAIChE Annual Meeting, Conference Proceedings

Conference

Conference2008 AIChE Annual Meeting, AIChE 100
CountryUnited States
CityPhiladelphia, PA
Period11/16/0811/21/08

Fingerprint

Distillation columns
Exergy
Methanol
Reboilers
Preheating
Thermodynamics
Thermoanalysis
Costs
Steam reforming
Composite materials
Enthalpy
Energy utilization
Simulators
Economics
Hot Temperature

Keywords

  • Column grand composite curves
  • Exergy loss
  • Retrofitting
  • Thermodynamic analysis
  • Thermodynamic efficiency

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

Demirel, Y. (2008). Retrofit of distillation columns in a methanol plant. In AIChE100 - 2008 AIChE Annual Meeting, Conference Proceedings (AIChE Annual Meeting, Conference Proceedings).

Retrofit of distillation columns in a methanol plant. / Demirel, Yaşar.

AIChE100 - 2008 AIChE Annual Meeting, Conference Proceedings. 2008. (AIChE Annual Meeting, Conference Proceedings).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Demirel, Y 2008, Retrofit of distillation columns in a methanol plant. in AIChE100 - 2008 AIChE Annual Meeting, Conference Proceedings. AIChE Annual Meeting, Conference Proceedings, 2008 AIChE Annual Meeting, AIChE 100, Philadelphia, PA, United States, 11/16/08.
Demirel Y. Retrofit of distillation columns in a methanol plant. In AIChE100 - 2008 AIChE Annual Meeting, Conference Proceedings. 2008. (AIChE Annual Meeting, Conference Proceedings).
Demirel, Yaşar. / Retrofit of distillation columns in a methanol plant. AIChE100 - 2008 AIChE Annual Meeting, Conference Proceedings. 2008. (AIChE Annual Meeting, Conference Proceedings).
@inproceedings{96b9e4a66ba14db48b3d6666a11835a4,
title = "Retrofit of distillation columns in a methanol plant",
abstract = "Through its 'Column Targeting Tools' the Aspen plus simulator performs the 'Thermal Analysis' for rigorous column (RadFrac) calculations and produce Column Grand Composite Curves (CGCC) and exergy loss profiles. The CGCC displays the net enthalpies for the actual and ideal operations at each stage, and the cold and hot heat utility requirements, while the exergy loss profiles indicate the level of irreversibility at each stage including the condenser and reboiler. Therefore, the thermal analysis can identify the targets for restructuring and modifications, and may be helpful in suggesting retrofits. Some of the retrofits consist of feed conditioning (preheating or precooling), feed splitting, reflux adjustments, and adding side condensers and reboilers. These retrofits target a practical near minimum thermodynamic loss and suggest modifications for existing distillation columns by increasing the efficiency in energy utilization. This study uses the CGGC and the exergy loss profiles to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a methanol plant. Effectiveness of the retrofits is assessed by means of thermodynamics optimum and economics. The methanol plant is based on steam reforming and utilizes two distillation columns to purify the methanol in its separation section. The first column operates with 51 stages, has a side heat stream to the last stage, a partial condenser at the top and a side condenser at stage 2, and no reboiler. The second column operates with 95 stages, has a side heat stream to stage 95, a total condenser, and high reflux ratio. For the first column, the retrofits consisting of a feed preheating and a second side condenser at stage 4 have reduced the total exergy loss by 21.5{\%}. For the second column, the retrofits of two side reboilers at stages 87 and 92 have reduced the total exergy loss by 41.3{\%}. After the retrofits, the thermodynamic efficiency has increased to 55.4{\%} from 50.6{\%} for the first column, while it has increased to 6.7{\%} from 4.0{\%} for the second. The suggested retrofits have reduced the exergy losses and hence the cost of energy considerably, and proved to be more profitable despite the increases fixed capital costs of the distillation columns of the methanol plant.",
keywords = "Column grand composite curves, Exergy loss, Retrofitting, Thermodynamic analysis, Thermodynamic efficiency",
author = "Yaşar Demirel",
year = "2008",
month = "12",
day = "1",
language = "English (US)",
isbn = "9780816910502",
series = "AIChE Annual Meeting, Conference Proceedings",
booktitle = "AIChE100 - 2008 AIChE Annual Meeting, Conference Proceedings",

}

TY - GEN

T1 - Retrofit of distillation columns in a methanol plant

AU - Demirel, Yaşar

PY - 2008/12/1

Y1 - 2008/12/1

N2 - Through its 'Column Targeting Tools' the Aspen plus simulator performs the 'Thermal Analysis' for rigorous column (RadFrac) calculations and produce Column Grand Composite Curves (CGCC) and exergy loss profiles. The CGCC displays the net enthalpies for the actual and ideal operations at each stage, and the cold and hot heat utility requirements, while the exergy loss profiles indicate the level of irreversibility at each stage including the condenser and reboiler. Therefore, the thermal analysis can identify the targets for restructuring and modifications, and may be helpful in suggesting retrofits. Some of the retrofits consist of feed conditioning (preheating or precooling), feed splitting, reflux adjustments, and adding side condensers and reboilers. These retrofits target a practical near minimum thermodynamic loss and suggest modifications for existing distillation columns by increasing the efficiency in energy utilization. This study uses the CGGC and the exergy loss profiles to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a methanol plant. Effectiveness of the retrofits is assessed by means of thermodynamics optimum and economics. The methanol plant is based on steam reforming and utilizes two distillation columns to purify the methanol in its separation section. The first column operates with 51 stages, has a side heat stream to the last stage, a partial condenser at the top and a side condenser at stage 2, and no reboiler. The second column operates with 95 stages, has a side heat stream to stage 95, a total condenser, and high reflux ratio. For the first column, the retrofits consisting of a feed preheating and a second side condenser at stage 4 have reduced the total exergy loss by 21.5%. For the second column, the retrofits of two side reboilers at stages 87 and 92 have reduced the total exergy loss by 41.3%. After the retrofits, the thermodynamic efficiency has increased to 55.4% from 50.6% for the first column, while it has increased to 6.7% from 4.0% for the second. The suggested retrofits have reduced the exergy losses and hence the cost of energy considerably, and proved to be more profitable despite the increases fixed capital costs of the distillation columns of the methanol plant.

AB - Through its 'Column Targeting Tools' the Aspen plus simulator performs the 'Thermal Analysis' for rigorous column (RadFrac) calculations and produce Column Grand Composite Curves (CGCC) and exergy loss profiles. The CGCC displays the net enthalpies for the actual and ideal operations at each stage, and the cold and hot heat utility requirements, while the exergy loss profiles indicate the level of irreversibility at each stage including the condenser and reboiler. Therefore, the thermal analysis can identify the targets for restructuring and modifications, and may be helpful in suggesting retrofits. Some of the retrofits consist of feed conditioning (preheating or precooling), feed splitting, reflux adjustments, and adding side condensers and reboilers. These retrofits target a practical near minimum thermodynamic loss and suggest modifications for existing distillation columns by increasing the efficiency in energy utilization. This study uses the CGGC and the exergy loss profiles to assess the performance of the existing distillation columns, and reduce the costs of operation by appropriate retrofits in a methanol plant. Effectiveness of the retrofits is assessed by means of thermodynamics optimum and economics. The methanol plant is based on steam reforming and utilizes two distillation columns to purify the methanol in its separation section. The first column operates with 51 stages, has a side heat stream to the last stage, a partial condenser at the top and a side condenser at stage 2, and no reboiler. The second column operates with 95 stages, has a side heat stream to stage 95, a total condenser, and high reflux ratio. For the first column, the retrofits consisting of a feed preheating and a second side condenser at stage 4 have reduced the total exergy loss by 21.5%. For the second column, the retrofits of two side reboilers at stages 87 and 92 have reduced the total exergy loss by 41.3%. After the retrofits, the thermodynamic efficiency has increased to 55.4% from 50.6% for the first column, while it has increased to 6.7% from 4.0% for the second. The suggested retrofits have reduced the exergy losses and hence the cost of energy considerably, and proved to be more profitable despite the increases fixed capital costs of the distillation columns of the methanol plant.

KW - Column grand composite curves

KW - Exergy loss

KW - Retrofitting

KW - Thermodynamic analysis

KW - Thermodynamic efficiency

UR - http://www.scopus.com/inward/record.url?scp=79952293021&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79952293021&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:79952293021

SN - 9780816910502

T3 - AIChE Annual Meeting, Conference Proceedings

BT - AIChE100 - 2008 AIChE Annual Meeting, Conference Proceedings

ER -