Hot-State Experimental Research on a Novel Coal-based Two-stage Gasification Process N^Weilong JinKey Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education, Meilong Road 130, Shanghai, People's Republic of China

摘要

A novel coal-based two-stage combined gasification process with heat recovery via chemical reaction was proposed by Institute of Clean Coal Technology, East China University of Science and Technology, which was aimed at the insufficient heat recovery of high temperature gas for existing entrained-flow gasifiers. The effects of coal types (lignite, petroleum coke and anthracite), the mass of coal added (1000g, 1200g, 1400g and 1600g), and coal particle sizes (5-8mm, 8-10mm, 10-15mm and 15-20mm) for the second stage on gasification efficiency were researched in an experimental two-stage hot-state gasifier. In addition, the influence of gas compositions from the first stage was also examined. The effective gas concentration (H_2+CO), low heat value (LHV) of syngas and carbon conversion rate as well as CO_2 and H_2O conversion rate were analyzed and compared under different operating conditions. Experimental results showed that the two-stage gasification process can lower the syngas temperature in the gasifier, and improve the effective components of the syngas significantly. The reactivity of lignite was better than petroleum coke and anthracite. The optimum amount of coal added to the second stage was 1400g, which occupied 10% of the handling capacity for the first stage, and the optimum coal particle size for the second stage was 8-10mm. The carbon conversion as well as CO_2 and H_2O conversion rate in the gasifier presented an increase trend with the increase of invalid components (CO_2+H_2O) in syngas from the first stage. Furthermore, the process had good environment benefits by reducing the emission of CO_2.