生物质与煤共气化灰熔融和结渣特性  

Fusion and slagging characteristics of ash produced by co-gasification of biomass and coal

作　　者：王立群[1] 张羽钧 马亮 WANG Liqun;ZHANG Yujun;MA Liang(School of Energy and Power Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学能源与动力工程学院,江苏镇江212013

出　　处：《中南大学学报（自然科学版）》2021年第4期1307-1315,共9页Journal of Central South University:Science and Technology

基　　金：国家科技支撑计划项目(2015BAD21B06)。

摘　　要：为解决生物质气化引起的焦油、团聚和结渣问题,以木屑和水稻秸秆为原料,添加贫煤并以生物质与煤质量比为4物料比共气化。将木屑灰、水稻秸秆灰及对应的混合灰作为研究对象,采用X射线荧光光谱(XRF)、X射线衍射(XRD)和三元相图等方法研究还原气氛下生物质灰和混合灰熔融特性的变化,利用扫描电镜(SEM)研究结渣特性。研究结果表明:在灰熔融特性上,混合灰优于生物质灰,因为添加贫煤降低混合灰中碱性氧化物含量,同时高温下混合灰产生较高熔点的矿物,包括斜铁辉石(FeSiO3)和硅灰石(CaSiO3)等钙铁矿物,而高温下生物质灰中矿物含量少且熔点低。在三元相图中,混合灰均处于方石英相区,且趋近贫煤灰所在的刚玉相区,灰熔融温度呈升高的趋势。Al2O3的增加能提高灰熔融温度,因为Al2O3的熔点高,且促进生成高熔点矿物,同时熔融温度还受到低温共熔的影响。混合灰的结渣特性也优于生物质灰的结渣特性,两者发生同等熔融时,混合灰所处温度明显比生物质灰的温度高。Sawdust and rice straw were used as raw biomass materials,and a method by lean coal addition with biomass-to-coal mass ratio of 4 was applied to overcome the problems of tar,bed agglomeration and slagging produced by biomass during gasification in fluidized bed gasifier.Biomass ash and blend ash composed of corresponding biomass and lean coal were research objects.X-ray fluorescence spectrometer(XRF),X-ray diffraction(XRD)and ternary phase diagram were used to analyze the differences between biomass ash and blend ash on fusion characteristics in reducing atmosphere,and scanning electron microscope(SEM)was utilized to study slagging characteristics of ash samples.The results show that in terms of ash fusion characteristics,blend ash is superior to biomass ash,because coal addition could reduce the amount of alkaline oxides of blend ash,and high-melting-point minerals are detected,which are produced at high temperatures and effectively increase the ash fusion temperatures(AFTs)in blend ash,including wollastonite and clinoferrosilite,while the content of minerals,with low melting points,is less in biomass ash.In ternary phase diagram,the position of two blend ashes is in cristobalite area,which approaches the mineral area where lean coal ash is located,which shows AFTs of blend ash has a tendency to rise.AFTs increase with the increase of Al2O3,because Al2O3 has a high melting point and can generate high-melting mineral by reaction.AFTs are also affected by low temperature eutectic caused by some substances.Simultaneously,in aspect of slagging characteristics,blend ash is better than biomass ash.The same grade melting is observed in biomass ash and blend ash through SEM,and the ambient temperature of blend ash is higher than that of biomass ash counterpart.

关 键 词：还原气氛 生物质 灰熔融特性 结渣特性 矿物转变 三元相图 低温共熔 

分 类 号：TK6[动力工程及工程热物理—生物能] TQ544[化学工程—煤化学工程]