Research On The Influence Of Coal Quality Characteristics And Chemical Structure On The Performance Of Coal Water Slurry

Coal water slurry（CWS）is a kind of clean coal based fluid fuel,which has the advantages of small environmental pollution and high combustion efficiency.It can be used as an oil substitute or as a raw material for gasification.With the development of coal chemical industry in China,the application of CWS technology has been widely concerned.The preparation of CWS has certain restrictions on the selection of coal.High-quality coal is the ideal material.But high-quality coal resources are gradually consumed with the development of coal chemical industry.Therefore,it is necessary to improve the slurry ability of poor coal and expand the coal’s range.The properties of coal are different.So the study of coal structure is beneficial to the understanding of coal properties and provides reference for the efficient and cleaning utilization of coal.In this paper,11 different coal samples were used to study the CWS’s properties of single coal and coal blending.And the study on coal structure of three coals CH,XS and YM provides a theoretical basis for the efficient utilization of coal.The main results of this paper are as follows:1.The slurry ability,rheology and stability of single coal water slurry were studied under the same condition.CH belongs to anthracite coal and its coal rank is high.The fixed viscosity concentration of CH is up to 70.3%.However,the fixed viscosity concentration of YM is 63.95%,because it has lower metamorphic grade.The apparent viscosity decreases with the increasing of shear rate,and shows the characteristic of shear thinning,which belongs to pseudoplastic fluid.The high concentration of CWS is greatly affected by shear rate than the low concentration of CWS.The stability of CWS with poor coal is better than the CWS with high-quality coal.The fixed viscosity concentration of the coal sample decreases with the increasing of moisture,O/C,volatiles and increases with the increasing of ash.Study on the coal water contact angle of CH、SJS、XS、YM shows that the slurry ability of the coal with large contact angle is better.2.In this paper,some coal samples with large difference in slurry ability are selected to study the effect of coal blending on CWS.The result shows that the relationship of fixed viscosity concentration of coal blending water slurry and the proportion of the coal with good slurry ability is not positive.The slurry ability of coal blending water slurry is nonlinearity.And the coal blending water slurry belongs to pseudoplastic fluid.The influence of coal blending on the stability is complicated.Some coal blending can improve the stability of CWS,while some coal blending can reduce the stability.3.The basic information of coal samples（CH,XS and YM）was obtained by means of FT-IR,XRD,XPS,¹³C-NMR.The structural model parameters of each coal sample were calculated.Using Chemoffice 2014 software to draw the plane structure model of coals,the molecular formula of CH,XS and YM is C₁₅₀H₇₀N₂O₃,C₁₃₆H₉₄N₂O₆ and C₁₁₀H₆₆N₂O₁₀ respectively.And the optimal coal structure model was obtained by simulation.4.The number of oxygen-containing functional groups decreases with the increasing of coal metamorphism.The number of oxygen-containing functional groups will affect the surface properties of coal,further affect the slurry ability.The aromaticity of anthracite CH is greater than that of bituminous coals XS and YM,indicating that anthracite CH has a relatively high degree of metamorphism and stable structure.