Effect of Pyrolysis Temperature on Gasification Reactivity of Solvent Extracted Ash-free Coals Insoluble Residual Coals

摘要

Gasification of coal to syngas has gained popularity, thanks to use of cheap and abundant coal. Coal that is composed of thousands of different macromolecules experiences thermal decomposition in most of the applications, breaking the aliphatic bonds, releasing volatile matters, and rearranging the aromatic matrix. Therefore, the reactivity of the chars is different from the parent coals, and which are significantly influenced by the heating temperature. In order to investigate the effect of pyrolysis on the gasification reactivity, ash-free coal (AFC) that is produced by solvent extraction of Indonesian lignite, insoluble residual coal (RE), and original raw coal (RA), are pyrolyzed at 300 – 900 oC with 100 oC interval and then gasified under steam. The gasification rate of the different chars of the same origin prepared below 700 oC is generally comparable with each other, and it drops for the chars pyrolyzed above 800 oC. The gasification behavior of AFC and RE varies depending on the polarity of the extraction solvent. The steam gasification and associated CO to CO2 conversion of the AFCs are significantly enhanced by K2CO3 catalyst, indicating catalytic coal gasification at mild condition as well as repeated use of the catalyst is achievable when AFC is gasified as feedstock.