1. Introduction - Firenze University Press

6. Conclusions
The process simulation, characteristics analysis and system integration of CO2 capture based on a
typical China’s existing coal-fired power plant with supercritical parameters are carried out in this
paper. From the work completed in this study, some important conclusions can be drawn out and a
few of interesting integration measures are put forward.
(1) When an existing power plant is transformed into a CO2 capture plant using chemical absorption
methods, some special problems will be met with, which is very different from the virtual plant.
On the one hand, it will be difficult to find a suitable extraction point for the large amount of
steam which has to be supplied to the CO2 capture process. On the other hand, some component
of the existing power plant, especially the steam turbine, will significantly deviate from their
original design conditions because of a large amount of steam extracted from steam/water cycle,
resulting in a large efficiency penalty.
(2) When retrofitting existing power plant, due to the constraint of existing equipments, the energy
penalty of CO2 capture will tend to be even higher. For example, because the parameters of
extraction steam doesn't match with the steam parameters for CO2 capture process, it will be
certain to bring additional power loss. Eventually, efficiency penalty of CO2 capture in an
existing power plant (Case 2) can be 4% points higher than that of a redesigned new power
plant(Case 1).
(3) In this study, through the special (unique) system integrations(Case 3, Case 4, Case 5), the
efficiency of existing 600MW supercritical power plant increased by 4.02%, rising from
26.40%(Case 2) to 30.42%(Case 5). The overall studies in this report show that if MEA
absorption is adopted to recover CO2 from flue gas of a power plant, with a CO2 recovery ratio
of 90% the efficiency penalty for the power plant will be 9.86% points, and the extraction steams
flow is 1.553 kg steams/kg CO2.
Acknowledgments:
The paper is supported by National Nature Science Fund of China (No. 51006034, No. 51025624),
and the National Major Fundamental Research Program of China (No. 2009CB219801, No.
2011CB710706).
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