Stability and rheology of carbon-containing composite liquid fuels under subambient temperatures

Abstract

Since an average annual temperature for the storage and transportation of composite liquid fuels (CLF) in different countries can vary significantly, covering subambient temperatures and even negative, the challenge of providing their high stability, appropriate to industrial use fluidity classes, and rheology due to the use of functional additives becomes urgent. The study develops the new formulation of CLF tested for phase separation, sedimentation stability, fluidity, and rheology after 72-h holding at temperatures from −5 °C to 25 °C. CLF are based on coking coal and coal sludge particles with the addition of dispersants, diluting agents, viscosity and water loss reducers. Analyzing stability and fluidity, CLF based on 50 wt% of the coal sludge and 48 wt% of water (or 20 wt% glycerol solution when holding at 0 °C and −5 °C) with the addition of 1 wt% acid sodium polyphosphate as a deflocculant and diluent and 1 wt% isononylphenol as a dispersant is determined as the most stable composition. Three factors are established that determine the combined effect of dispersants and regulators of physical-chemical properties on rheology. An analysis of rheology and stability identified additional three promising coal-based compositions containing a coal phosphate reagent, acidic sodium pyrophosphate, isononylphenol, and mono- and dialkylphenols.