CO_2 capture from coal combustion using chemical-looping combustion

摘要

Chemical-looping combustion (CLC) is a combustion technology where an oxygen carrier is used to transfer oxygen from the combustion air to the fuel, thus avoiding direct contact between air and fuel. Thus, CO_2 and H_2O are inherently separated from the rest of the flue gases, and no major energy is expended for this separation. The paper presents results from a three year project devoted to developing the CLC technology for use with syngas from coal combustion. The project has focused on ⅰ) the development of oxygen carrier particles, ⅱ) establishing a reactor design and feasible operating conditions and ⅲ) construction and operation of a continuously working hot reactor. Approximately 300 different oxygen carriers based on oxides of the metals Ni, Fe, Mn and Cu were investigated with respect to parameters which are important in a CLC system, and from these investigations, several particles were found to possess suitable qualities as oxygen carriers. Several cold-model prototypes of CLC based on interconnected fluidized were tested, and from these tests a hot prototype CLC reactor system was constructed and operated successfully using three carriers based on Ni, Fe and Mn developed within the project for 30-70 h.