LIU Zhen,LI Jun,ZHANG Jiansheng.Ash and slag characteristics under co-gasification of coal and extract residue of direct coal liquefaction residue[J].Clean Coal Technology,2023,29(11):113-121.

Co-gasification with coal is an effective way to achieve the resource utilization of coal direct liquefaction residue (ER) and improve the overall economy of direct coal liquefaction project. The flow properties of slag in the gasification process is the key parameter thataffects thegasificationoperatingconditions.Thefusioncharacteristics,viscosity - temperaturecharacteristicsandcrystalcharacteristics co-gasification with coal and ER were analyzed by ash fusion point meter, high-temperature rotating viscometer, XRD(Diffraction of X-Rays) and SEM (Scanning Electron Microscope). Based on the coal ratio and operating conditions of Shell gasifier, theoptimal blending ratio of ER and gasification operating conditions were determined from the perspective of ash chemistry. The results showthat there is high ash, high iron, high calcium and high sulfur in the ER,and its ash composition is slightly alkaline. With the increase ofthe amount of ER in coal, the ash content, iron content and w(SiO2) / w(Al2O3) increase gradually. The whole liquid phase temperature(Tliq) becomes lower when the mass fraction of the raffinate is above 8%, and the type of slag changes from glass to crystalline when theamount of raffinate added is over 20%. The XRD and SEM analysis results indicate that the precipitation of anorthite cause a change in thetype of slag. The precipitation of calcium feldspar is mainly due to the addition of residual substances, which reduces the viscosity of slagand enhances the diffusion ability of clusters in slag. Considering to the conditions of Shell gasifier for operation and the requirements foriron content in coal ash, the optimal blending ratio of ER is 10% for co-gasification of coal and ER, and the corresponding operating window is 1 335-1 557 ℃ . The research results provide guidance for co-gasification of coal and ER, and can improve the economy of the direct coal liquefaction process.

刘臻(1982—),男,内蒙古包头人,高级工程师,博士研究生。E-mail:zhen.liu.v@ceic.com

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