Performance of a 50 kWth coal-fuelled chemical looping combustor

Abstract

A 50 kWth chemical looping combustion (CLC) reactor for coal has been successfully constructed and operated. A turbulent fluidized bed acts as the air reactor (AR) to achieve high solid circulation rate, while a bubbling fluidized bed operates as the fuel reactor (FR) to guarantee sufficient solid residence time. Two risers are separately connected to the AR and FR to provide the driving force for oxygen carrier (OC) circulation. A four-chamber loop seal (LS) is installed between AR and FR, playing the roles of a gas-sealing configuration and also a carbon stripper to convert unreacted char.Low-cost natural hematite was used as OC and Shenhua bituminous coal was used as fuel. A series of tests was conducted to investigate the performance of the newly constructed CLC reactor under different operational parameters. Effects of temperature, inlet gas velocity and H2O concentration in fluidizing agent, on the performance of the CLC reactor were investigated. The relatively stable pressure drop attained in the FR indicated successful operation of the CLC system. During 120 min continuous running with a bed inventory of 100 kg in FR, the highest CO2 yield reached to 0.91 and the combustion efficiency was 0.86 at 1000 °C.