Influence of membrane CO ₂ separation on the operating characteristics of a coal-fired power plant

The influence of a carbon capture and storage (CCS) installation with membrane separation on the efficiency and economic characteristics of a supercritical coal unit has been presented. The algorithm of the minimisation of energy consumption of the process of membrane CO ₂ separation was worked out. It allows, with the assumed parameters of separated CO ₂ (e.g., purity and recovery ratio), determination of the optimum process parameters such as permeate and feed pressure and the membrane surface area. The possibilities include significant lowering of the energy consumption of the CCS installation through the use of compressors and vacuum pumps with interstage cooling. It was shown that the supercritical power unit throughout the use of the analysed installation will cause only a 6.07 percentage points efficiency decrease, which is realistically 6.96 percentage points. The analysis of the economic consequences of the introduction of the CCS installation to the examined unit was performed. The break-even price of electricity and the cost of avoided emissions were determined. The influences of the lifetime of the membrane and its price on the mentioned quantities were also investigated.