Study On Fusibility And Fluidity Of Coal Ash Slag And Hot Model Of Membrane Wall Entrained-flow Gasifier

On the background of entrained-flow pulverized coal gasification technology, fusability and fluidity of coal ash and slag from industrial and pilot test gasifier were mainly studied in this paper. Cold model feed and hot model trial firing experiment of pulverized coal were performed in membrane wall entrained-flow gasifier.The ash fusability of coal blending was studied by ash fusion point determination meter. The effects of the content of high fusability coal and acid-base ratio on the ash fusability of coal blending were great. Based on the ash fusion temperatures of the experimental test, BP artificial neural networks were used to predict coal ash flow temperatures based on experiment results of ash fusion temperatures. The prediction results were in good agreement with experiment results.Ash fusion point determination meter and high-temperature rotational viscometer were applied to study the fusibility and viscosity-temperature characteristics of coal ash and slag from blended coal used in Shell gasifier and Baodian coal used in pilot test gasifier. The results show that content of SiO2 and alkaline oxide(CaO,K2O,Na2O) in coal ash is relatively high. Content of MgO and TiO2 in slag is relatively high. The fusability of coal ash was different with that of slag. In the range of gasifier operating temperature (1400℃-1500℃), viscosity-temperature curves of coal ash were similar with those of slag. Viscosities of coal ash were slightly higher than those of slag. The critical viscosity temperatures of slag were slightly higher than those of coal ash. FactSage software was applied to calculate liquidus temperatures and crystal precipitation amounts of coal ash and slag. In Al2O3-SiO2-CaO-FeO quaternary phase diagram, liquidus temperatures of slag were higher than those of coal ash. Crystal precipitation amounts of slag were higher than those of coal ash near the critical viscosity temperature.Based on bench-scale membrane wall entrained-flow gasifier, cold model feed and hot model trial firing experiment were first performed using pulverized coal and diesel oil.