Heat Integration of KIERDRY Process with a Power Plant Using gPROMS

Abstract

In this study, thermal efficiency of power plant has been evaluated by integrating the KIER-developed dry-sorbent CO2 capture process (KIERDRY) with a pulverized coal-fired power plant using a commercial simulator, gPROMS. A simple basic KIERDRY model has been developed and connected it to PCPP (Pulverized Coal Power Plant) example in gCCS, a system modelling tool for support of design and operating decisions across the CCS chain. The PCPP capacity of 500 MWe and the KIERDRY capacity of 150 MW (125 tonCO2/hr based on captured amount) have been set as a base case. We consider HP steam(307 oC, 31bar) and IP steam(461 oC, 14∼14.6bar) as the utility steam of a regenerator in KIERDRY since the steam condition of a regenerator has been set to approximately 14.6∼15bar, saturated. Totally 5 cases have been evaluated: (1-1) Use HP steam, use condensate to make a process steam, and return to condensate(1bar); (1-2) Use HP steam and return to 5th feed water heater(12bar); (2-1) Use IP steam, use condensate to make a process steam, and return to condensate(1bar); (2-2) Use IP steam and return to 5th feed water heater(12bar); (2-3) Use IP steam, do additional heat integration by preheating dry sorbents at loop-seal, and return to 5th feed water heater(12bar). As a result, the condensate generated at the regenerator should be returned to the power plant rather than used to make a process steam, which is supplied as a reactant for the carbonation reaction. Based on several case studies, the reduction of the power output of the PCPP with KIERDRY has been varied from 29.2 MWe(minimum penalty) to 71.7 MWe(maximum penalty). Thus, it can be concluded that the energy penalty of KIERDRY has been significantly reduced by how heat has been integrated with PCPP.