Volatile matter capture by calcined limestone under Calcium-Looping process conditions

摘要

This work proposes an approach to avoid hot-spot formation in the regenerator of Calcium-Looping CO2 capture process. The basic principle is to capture volatile matter evolved from the fuel by porous sorbent (CaO) particles followed by the formation of solid carbon deposit within the particles. By reducing the amount of volatile matter, rapid combustion of volatile matter in the regenerator can be suppressed. Experimental work was carried out to assess the volatile matter capture by CaO particles in a fixed bed. Higher temperature was found to be favorable to capture volatile matter. Also combustion rate of carbon deposit was measured. The combustion rate of carbon deposit was found to be sufficiently lower than the rate of volatile matter combustion. The influences of temperature and oxygen concentration on deposit combustion rate were not remarkable. Several designs for fuel feed modification that enable volatile matter capture are proposed.