Synergistic effects of mixing waste activated carbon and coal in co-slurrying and CO2 co-gasification

Abstract

As a raw material, applications of waste activated carbon (WAC) in synergy with coal powder to prepare coal water slurry (CWS) and perform high-temperature gasification is a novel strategy for disposing WAC. Combining BET surface analysis, contact angle measurement, and thermogravimetric-Fourier transform infrared (TG-FTIR) methods, the physico-chemical properties and CO2 gasification behaviors of coal-waste activated carbon-slurry (CWACS) were evaluated. Compared to coal, WAC exhibited an excellent adsorption capacity and a stronger surface wettability. When the WAC mixing ratio was increased from 0 to 15%, the CWS solid concentration decreased from 62.28% to 59.44%. CWACS exhibited a shear-thinning flow behavior, and the higher the WAC mixing ratio, the more obvious the pseudoplastic characteristics. Moreover, WAC enhanced the storage stability of the CWS. Under the catalysis of Na, Ca, and Fe among others, the CO2 gasification reaction of CWACS coke moved forward to the low-temperature stage. The high fixed carbon content of WAC, as well as its unique tar adsorption and catalytic cracking effects, increased the CO gas component in the synthesis gas.