A techno-economic analysis of post-combustion CO2 capture and compression applied to a combined cycle gas turbine: Part II. Identifying the cost-optimal control and design variables

Abstract

A detailed optimization-orientated model of monoethanolamine-based CO2 capture plant and compression train in which all the technical and economic assumptions are defined and/or optimized was developed and used to simultaneously determine the cost optimal control and design variables including feed fraction ratio at different degrees of capture (DOC), which represents the amount of CO2 removed, for plant designs that partially bypass the CO2 capture process so as to achieve low to moderate reductions of CO2, but at lower overall cost. The effects of varying carbon prices on the levelized cost of CO2 capture and compression were also studied. The capture bypass option was observed to be the cost optimal choice for lower than 60% overall DOC. Carbon prices were observed to have a clear impact on the cost optimal DOC, with the cost-optimal DOC shifting from 70%⿿80% to 85%⿿90% at carbon prices of $4/tCO2to $23/tCO2 respectively. The study highlighted that if a suitably high carbon price does not materialize through a market mechanism, appropriate policies need to be put in place to achieve decarbonisation targets.