Department of Energy and Power Engineering, Tsinghua University
CHN Energy National Institute of Clean and-Low-Carbon Energy

与煤共气化是实现煤直接液化残渣萃余物(ER)资源化利用,提升煤直接液化工程整体经济性的重要途径。气化过程灰渣的流动性是影响气化操作条件的重要参数,利用灰熔点仪、高温旋转黏度计、XRD及SEM等测试手段考察了ER与煤共气化的灰渣熔融特性、黏温特性及晶体特性,并结合壳牌气化装置入炉煤配比和操作条件,从灰化学角度确定ER的最佳掺混比例及气化操作窗口。结果表明:ER属于高灰、高铁、高钙、高硫物质,且其灰成分偏碱性,随煤中ER添加量增大,掺混后的灰分、铁含量和硅铝比逐渐增大。当萃余物质量分数超8%,全液相温度Tliq降低,但萃余物添加量超20%时,熔渣类型从玻璃渣转变为结晶渣。XRD与SEM分析结果表明钙长石的析出造成熔渣类型改变,钙长石的析出主要是因为萃余物的添加使熔渣黏度降低,熔渣中团簇的扩散能力增强,有利于结晶行为。结合Shell气化炉的操作条件及对煤灰中铁含量的要求,当萃余物添加量为10%时,共气化熔渣适合气化炉排渣,对应的排渣窗口为1335~1557℃。该研究结果为ER与煤共气化提供指导,提高煤直接液化流程的经济性。

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.

国家能源投资集团科技创新资助项目(GJNY-18-72,GJNY-21-85)

刘臻,李君,张建胜.煤液化残渣萃余物与煤共气化的灰渣特性[J].洁净煤技术,2023,29(11):113-121.

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.