Low-temperature syngas separation and CO_2 capture for enhanced efficiency of IGCC power plants

摘要

The present work proposes low-temperature syngas separation as an alternative to the use of solvent absorption–desorption processes for CO_2 capture from IGCC power plants. In the low-temperature process in consideration, CO_2- 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 CO_2 capture ratio of 73% simulation results show a potential specific capture and compression power of approximately 0.36 MJ/kgCO_2 including sulphur pre-removal. Higher CO_2 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 CO_2 capture from IGCC power plants and may hence be an interesting energy- and cost-efficient alternative to conventional capture methods.