A technical and economic assessment of variants for CO₂ separation from synthesis gas

ABSTRACT

An analysis of carbon dioxide (CO₂) removal process from synthesis gas has been carried out in this work. CO₂ removals by physical and chemical solvents are the most often used. The most important factors that affect cost and performance of a CO₂ recovery unit are the number of flash drum separation units, and the pressure drop pattern among them. Different variations of this process were simulated using Hysys software, and the capital and operational expenditures for these plants were estimated. The focus was to reach an optimum process to minimize the total unit cost of separated CO₂. The results indicate that for a fixed number of separation units, the case with uniform pressure drop pattern has the minimal cost and energy consumption. On the other hand, it was revealed that among the cases with uniform pressure drop pattern, the one with four separation units will be the optimum case.

KEYWORDS:

• CAPEX/OPEX analysis
• CO₂ removal
• physical absorption
• selexol process
• simulation

Acknowledgments

The authors thank Mr. Shadman Rad, a Ph.D. candidate at Sharif University of Technology, for hints on the simulation work. The authors also express sincere thanks to Dr. Klaus Joerg from Tecon Engineering GmbH for paper review and erudite comments.

Nomenclature

AC	=	air cooler
E	=	cooler
FD	=	flash drum
K	=	compressor
P	=	pump

Notes

¹ Capital expenditure/operational expenditure.