The resource utilization of algae—Preparing coal slurry with algae

Abstract

Nowadays, the occurrence of harmful algal blooms is increasing rapidly all over the world. However, the methods of resource utilization of algae are very few. In this study, we propose a new way to dispose algae, which is gasification of coal–algae slurry. Coal slurries prepared with algae were investigated, and gasification reactivity of coal–algae slurry was compared with that of coal–water slurry (CWS). The results showed that, anaerobic fermentation, chemical treatment, high-speed shearing and heating are effective pre-treatment methods on reducing the viscosity of algae, which could obviously increase the maximum solids concentration of coal–algae slurry. When the de-ionized water/algae ratio is 1:1, the maximum solids concentration could get to 62.5 wt.%, which is almost the same as that of CWS. All the coal–algae slurries exhibit pseudo-plastic behavior, and this type of fluid is shear-thinning. Compared with CWS, the stability of coal–algae slurry is much better, which could be no solids deposition after 70 h. The coal–algae slurry displays better gasification reactivity than CWS.