(197a) Comment On Coal-Based Chemical Looping Combustion Process

There is a urgent push focusing on quick ways to curb CO2 emission based on wide-accepted scientific evidences on global warming. Under President Obama's economic stimulus and recovery plan, carbon managements will be the priority in fossil-fuel energy utilization, including coal-fired power plants to reduce CO2 emissions. The United States of America has abundant coal resources. More than 50% of U.S. electricity is derived from coal-based power. Consequently, the U.S. will have to either deal with or lead these upcoming carbon management regulations. However, carbon management in existing coal-fired power plants is burdened with high capital and operational costs based on post combustion capture processes.

This manuscript is to make technical comments on efforts made to develop coal-based chemical looping combustion process, which is an innovative coal-based combustion process dedicated to low cost carbon management and enhanced electricity generation efficiency. Oxygen carriers are tecnical cores of chemical looping combustion process. Selection and preparation of different oxygen carriers directly associated process economics and efficiencies. We are trying to conduct the feasibility study of coal-based chemical looing combustion, and thus point out the opportunity oxygen carriers, that lead to the successful development of coal-based chemical looing combustion process.

Based on selected oxygen carriers, a novel coal-based chemical looping combustion process are proposed. It could be retrofitted to existing coal fired power plants resulting in efficiency enhancement and capacity enlargement as well as 30%-70% CO2 capture under constraint of cost increase. This novel combustion process is the combination of chemical looping combustion (CLC) using novel oxygen carriers and subsequent combustion of residue char in existing, aged, low-efficiency, pulverized coal boilers. The potential impact of this process is the realization of affordable and timely CO2 capture technology that can be introduced into the existing coal-fired power generation fleet. The recovery of coal energy using different combustion technologies will be rationally optimized without energy penalty. Attrition-resisting and thermally stable oxygen carriers will be developed to achieve auto-thermal heat balance of the process, a high purity of CO2, favorable kinetics and participation of free-oxygen. The strategy of controlling multiple major air pollutants (SO2, NOx, and Hg) will be addressed.