Optimization of Advanced Flash Stripper for CO2 Capture using Piperazine

by Lin, Yu-Jeng; Rochelle, Gary T.


CO2 capture from coal-fired power plants using amine scrubbing typically incurs a 20-30% energy penalty. The major energy requirements are the reboiler duty for solvent regeneration and the compression work for CO2 sequestration. The advanced flash stripper using 8 m PZ was proposed, which recovers the stripping steam heat by employing cold and warm rich bypasses. The objective of this work is to quantify the benefits of the advanced regeneration system as energy and capital cost. The advanced flash stripper saves 10% total equivalent work that includes heat duty work, compression work, and pumping work compared to the simple stripper. From the economic analysis, it was found that the compressor and the cross exchangers are the two major capital costs of the regeneration system. By considering the cost of the main heat exchangers, the temperature approaches and pressure drops of the cross exchanger and the steam heater were optimized. The optimum LMTD of the cross exchanger is around 10 K, which saves 8% regeneration cost compared to the base case with 5 K. The annualized regeneration cost of the advanced flash stripper is $ 31/tonne CO2 at the optimum lean loading 0.20, providing 15% cost savings compared to the base case simple stripper (5 K cross exchanger LMTD). (C) 2014 The Authors. Published by Elsevier Ltd.

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