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Keywords:

  • CO2 capture;
  • carbonation/calcination;
  • energy integration;
  • supercritical cycle;
  • thermal efficiency

Abstract

This work analyses a Ca looping system that uses CaO as regenerable sorbent to capture CO2 from the flue gases generated in power plants. The CO2 is captured by CaO in a CFB carbonator while coal oxycombustion provides the energy required to regenerate the sorbent. Part of the energy introduced into the calciner can be transferred to a new supercritical steam cycle to generate additional power. Several case studies have been integrated with this steam cycle. Efficiency penalties, mainly associated with the energy consumption of the ASU, CO2 compressor and auxiliaries, can be as low as 7.5% p. of net efficiency when working with low-CaCO3 make-up flows and integrating the Ca looping with a cement plant that makes use of the spent sorbent. The penalties increase to 8.3% p. when this possibility is not available. Operation conditions aiming at minimum calciner size result in slightly higher-efficiency penalties. © 2010 American Institute of Chemical Engineers AIChE J, 2011