Evaluation of process upgrades and novel solvents for the post combustion CO_2 capture process in pilot-scale

摘要

In this work, a number of different process upgrades have been implemented at a 1 ton/hr CO_2 capture test facility operating on a slipstream of flue gas from a coal-fired power plant. The benefits of the upgrades have been assessed through tests using monoethanolamine (MEA) as well as novel solvents. Amongst others the solvent cross flow heat exchanger was improved resulting in a closer temperature approach. The improvement of the heat exchanger was found only to reduce the energy requirement marginally. It was furthermore found that applying inter-stage cooling in the lower section of the absorber did not benefit the MEA process significantly, whereas with novel solvents, the regeneration energy could be reduced with up to 7%. Introducing a vapour recompression cycle on the lean solvent loop was found to lower the regeneration energy with up to 20% with MEA but to a lesser extent with novel solvents. In all cases the introduction of vapour recompression significantly increased the auxiliary power consumption. All in all, a saving in the regeneration energy of close to 25% compared to that of the standard MEA process (3.7 GJ/ton CO_2) could be realised with the tested process improvements and novel solvents.