The Effects Of Ash Fusion Behavior Of High Ash Fusion Temperature Coal By Textile Dyeing Sludge Addition

To address the slagging problem during coal entrained-flow bed（EFB）gasification,meager-lean coal（MC）,anthracite coal（AC）,and bituminous coal（BC）ashes were investigated;the influences of textile dyeing sludge（TDS）on the fusing characteristics of three kinds of high ash fusion temperature（AFT）coal were explored under a reducing atmosphere.And analyzed the change mechanism of coal ash melting behavior by TDS was investigated by X-ray diffraction,Fourier Transform Infrared Spectroscopy（FTIR）,and Fact Sage calculation.（1）The flow temperature（FT）of MC decreased below 1380℃when the content of TDS reached 20-25%,which met liquid-slag removal requirements for EFB gasification.With the content of TDS increasing,the formations of low-melting minerals（e.g.,hercyniye,anorthite,and albite）caused the ash fusion temperature（AFT）of MC to decrease.The bridging oxygen（BO）bonds of the network structure were destroyed Fe²⁺with the increase in TDS content,lots of non-bridging oxygen bonds（NBO）formed,the R（R=（Q⁰+Q¹）/（Q²+Q³））value decreased.The peak strength of Si-O-Si and Si-O-Al bonds decreased gradually.Unstable silicate melt structure was produced,which decreased the AFTs of the mixtures.（2）The AFT of AC decreased with increasing TDS mass ratio,FT decreased to1370℃when TDS reached 20%.The formation of feldspar minerals and the low-temperature eutectic phenomenon were the main reasons for the decrease in AFTs.The BO bonds of the network structure of mixed ashes were destroyed by metal ions(e.g.,Fe²⁺,Ca²⁺,Na⁺)from the TDS.The NBO bonds were confirmed,the peak strengths of Si-O-Si and Si-O-Al bonds,and strengthens in the vibration of Si-O-M(M:Ca²⁺or Na⁺)bonds gradually decreased.The proportion of four configurations of Si-O bond also changed with the increasing TDS content,which promoted the depolymerization of silicate melt and led to the decrease in mixed AFT.Fact Sage calculations were in good agreement with the experimental ash fusion behavior.（3）As a typical high-silicon aluminum coal,BC has high AFT and viscosity.With the increase of TDS content,AFTs showed a“Z”trend,when TDS was 20-25%,FT was1383℃.Hercynite,anorthite,and albite were eutectic at low temperatures;the temperature at which all minerals had been changed into the liquid phase decreased with the increase of liquid content;the peak strength of the Si-O-Si bond weaken gradually,the proportion of Q³decreased,and Q²begins to increase slowly,leading to AFTs decreased.From the prediction of Fact Sage,the type of coal ash was transformed from crystal slag to glass slag with the increase of TDS content,the viscosity decreased from53.37 Pa·S to 7.3 Pa·S,the critical viscosity-temperature decreased,which met the requirements of EFT gasification on coal ash viscosity.