PROPERTIES OF COMPOSITE WATER-COAL FUEL STABILIZED WITH CARBON SUBMICRON MATERIAL AND AMINO ALCOHOLS

Composite Water-Coal Fuel (CWCF) is a viable alternative not only to solid coal but also to fuel oil and diesel fuel. The issue with combined systems is the low stability and heterogeneity of the distribution of coal particles, which causes an increase in the viscosity of dispersed systems. To regulate the rheological properties and stabilize the CWCF, additives such as dispersants, plasticizers, and stabilizers are used. The objective of the study was to examine the possibility of stabilizing composite water-coal fuel by adding amino alcohols and a submicron carbon substance (microdisperced carbon MC), obtained by plasma-chemical conversion of wastewater containing organics. The study focused on systems based on G-grade coal with a solid phase concentration of 61 %. Amino alcohols, 2-amino-2methyl-1-propanol (AMP), and 2-amino-2-ethyl-1,3-propanediol (AEPD) were added to the CWCF at concentrations of 0.05 %, 0.1 %, 0.15 %, and 0.2 % by weight of CWCF. Its apparent viscosity was measured using a Rheotest-2 rheometer at a temperature of 20 degrees C, and the shear-stress/shear-rate data for the CWCF covered a range of 0.1 to 470 s-1 . The sedimentation stability of the CWCF was assessed using a water-separating test and a storage period measured in days. The study found that the xi-potential of G-grade coal particles in the presence of amino alcohols is 40-45 mV in absolute value. The obtained CWCFs demonstrate a pseudoplastic type of flow in the range of shear rates of 0-80 s-1 . Systems with AMP are more stable than those with AERD. The introduction of highly dispersed carbon leads to an increase in the apparent viscosity of the systems and can be recommended for controlling the fluidity of the CWCF. To sum up, the sedimentation stability in the presence of highly dispersed carbon and amino alcohol additives increases from 5-6 to 10-14 days, almost twice. The sedimentation stability of these systems in the presence of & Mcy;& Scy; makes the CWCFs suitable for short-term storage.