Low-temperature syngas separation and CO2 capture for enhanced efficiency of IGCC power plants

The present work proposes low-temperature syngas separation as an alternative to the use of solvent absorption-desorption processes for CO2 capture from IGCC power plants. In the low-temperature process in consideration, CO2- and H-2-rich product streams are obtained by phase separation from compressed syngas by combining distillation, flash separation, internal heat recovery and auxiliary refrigeration. For the selected CO2 capture ratio of 73% simulation results show a potential specific capture and compression power of approximately 0.36 MJ/kg(CO2) including sulphur pre-removal. Higher CO2 capture ratio is obtainable and can be increased to about 85% by increasing the syngas feed pressure to about 110 bar. The low-temperature syngas separation process shows promising energy penalty figures for CO2 capture from IGCC power plants and may hence be an interesting energy-and cost-efficient alternative to conventional capture methods. (C) 2011 Published by Elsevier Ltd.