Improvement in coal content of coal–water slurry using hybrid coal impregnated with molasses

•Hybrid coal is an environmentally upgraded fuel by filling the coal pores with a biomass.•Water was hardly absorbed in the hybrid coal.•Void volume of hybrid coal was reduced.•CWS with high coal content can be prepared with hybrid coal.

To improve the efficiency of the gasification process of coal slurry, it is very important to determine the characteristics of coal–water slurry (CWS) and increase the coal content of CWS. If CWS is produced from low rank coal, the gasification efficiency will be diminished due to the difficulty of generating CWS with high coal content. Against this backdrop, studies have been conducted on the use of chemicals to improve slurry viscosity. However, to the best of our knowledge, few publications have reported on the modification of coal characteristics for CWS ability using biomass. Preparing high coal content CWS with low rank coal is generally difficult due to the outstanding water absorptive ability from its numerous hydrophilic pores. Therefore, we suggest hybrid coal slurry and demonstrate that hybrid coal, where surface and pore characteristics were modified by using molasses, makes it possible to prepare high coal content CWS with low rank coal.

Graphical abstractWhen coal pores are filled with biomass such as molasses, the coal surface becomes hydrophobic. Therefore, molasses impregnated hybrid coal makes it possible to prepare the high coal content CWS due to reduction of the water absorptive ability and the void volume of coal.Figure optionsDownload full-size imageDownload as PowerPoint slide