Preparation and rheological properties of oil–water–coal triplex synfuel using petroleum sulfonate as the dispersants

Triplex synfuel containing light oil, water and coal was prepared using octyl phenol polyethenoxy ether (OP) nonionic surfactant as emulsifying agent and petroleum sulfonate (PS) anionic surfactant as dispersing agent. Rheological properties of triplex mixture systems were investigated and the ratio of OP to PS was also optimized. The structures of PS products and naphthalene sulfonate and formaldehyde condensation compound (NSF) that has good dispersing performance were analyzed through FTIR spectrum. It was found that the dispersing performance of F# petroleum sulfonate which was sulfonated higher and contained more aromatic was the best. Furthermore it was better to be used as a kind of dispersant of triplex mixture systems. The triplex systems, with the ratio of the components of coal (C) to water (W) to oil (O) by weight was C:W:O = 63%:27%:10% and C:W:O = 65%:30%:5% were prepared when OP:PS-F# was 0.3%:0.8%. Moreover, at 25 °C apparent viscosities of triplex mixture systems were 415.0 and 1060.7 mPa s− 1 respectively at a shear rate of 100 s− 1 and it could be kept stable for more than two months. Two kinds of triplex synfuels can meet the demand of industrial quality.