A review of techno-economic models for the retrofitting of conventional pulverised-coal power plants for post-combustion capture (PCC) of CO2
In this paper, we compare and contrast the four most promising (i.e. commercially viable in the near future) technologies for the post-combustion capture (PCC) of CO2 that can be retrofitted to a conventional pulverised-coal power plant. These are CO2 capture using: (i) chilled ammonia, (ii) alkali-metal carbonates, (iii) membranes and (iv) calcium looping. These four technologies are compared to the benchmark monoethanolamine (MEA) scrubbing process in terms of efficiency penalty and cost indicators. We first review the relevant CO2 capture chemistry and typical process flow schematics, and then discuss energy- and mass-balance considerations. We consider 18 published techno-economic studies on these technologies and highlight the key measures, including net CO2 capture rate, net power output, net plant efficiency, capital costs, cost of electricity and cost of CO2 avoided. Calcium looping technology results in the lowest efficiency penalty (4.6%-points) and cost of PCC (36.3% increase in levelised cost of electricity). In addition, the cost of CO2 avoided by employing calcium looping for PCC can be as low as 29 USD2010 per tCO2. On all three of these criteria, calcium looping performs more than twice as well as the benchmark MEA PCC process.