Abstract:
Post-combustion capture by chemical absorption using MEA solvent remains the
only commercial technology for large scale CO2 capture for coal-fired power
plants. This paper presents a study of the dynamic responses of a post-
combustion CO2 capture plant by modelling and simulation. Such a plant consists
mainly of the absorber (where CO2 is chemically absorbed) and the regenerator
(where the chemical solvent is regenerated). Model development and validation
are described followed by dynamic analysis of the absorber and regenerator
columns linked together with recycle. The gPROMS (Process Systems Enterprise
Ltd.) advanced process modelling environment has been used to implement the
proposed work. The study gives insights into the operation of the absorber-
regenerator combination with possible disturbances arising from integrated
operation with a power generation plant. It is shown that the performance of the
absorber is more sensitive to the molar L/G ratio than the actual flow rates of
the liquid solvent and flue gas. In addition, the importance of appropriate
water balance in the absorber column is shown. A step change of the reboiler
duty indicates a slow response. A case involving the combination of two
fundamental CO2 capture technologies (the partial oxyfuel mode in the furnace
and the post-combustion solvent scrubbing) is studied. The flue gas composition
was altered to mimic that observed with the combination. There was an initial
sharp decrease in CO2 absorption level which may not be observed in steady-state
simulations. (C) 2010 Elsevier Ltd. All rights reserved.
