Acceleration effect of BDO tar on coal water slurry during co-gasification

Abstract

1,4-butanediol (BDO) is a general-purpose chemical feedstock. BDO tar is produced from the plant and is difficult to dispose of. This study has used the waste-coal-water-slurry (WCWS) technology to dispose of BDO tar and investigated the acceleration mechanism during co-gasification. The results show that the weight loss of BDO-tar-coal-water-slurry (BCWS) is more evident in the range of 200–300 °C because most of the organic constituents in BDO tar are lost. In the high-temperature field (>600 °C), the BCWS thermogravimetric (TG) curves migrate to the low-temperature zone, indicating that the co-gasification performance of the BCWS is significantly enhanced. The most distinct areas (“spotted area,” “rough area,” and “subsidence area”) exist on the surface of coal char by the alkali metal Na in BDO tar, which impedes the formation of defective carbon structures and amorphous carbon structures. Moreover, many defective and amorphous carbon emerged due to the tightly bound complexes with O and Na generated by the reaction between the unstable intermediate and the carbon matrix. BDO tar for BCWS co-gasification process is catalytic, suggesting that activation energy is lower than that of CWS.