摘要
低阶煤储量大,煤化程度低,具有反应活性高、挥发分较多等特点,直接燃烧利用率低,污染大,难以充分发挥价值。前人对煤热解催化剂进行大量研究,但鲜见用白云石负载镍作为催化剂应用于低阶煤催化热解的研究。为了实现低阶煤分质高效利用,以内蒙古褐煤为研究对象,采用等体积浸渍法制备白云石负载的镍基催化剂(Ni-白云石)并添加铜为助催化剂,采用热重分析法研究不同催化剂对内蒙古褐煤热解过程的影响,将制得的催化活性最好的催化剂进行电镜扫描,并且对制得的催化剂的活泼热解阶段进行动力学研究。研究表明:无催化剂条件下,煤样热解失重质量较少,热解转化率为14.67%;加入10%的白云石的原煤热解转化率为21.84%,比无催化剂原煤的热解转化率提高了6.17%;负载10%Ni后白云石催化原煤的热解转化率比白云石更高,可达28.14%,说明催化剂能促进煤热解行为,降低热解活化能,但不同催化剂的催化效果不一样,其中负载镍铜比1∶0.2的白云石催化剂对内蒙古褐煤热解的催化效果最好,Cu^(2+)过量会降低催化效果;扫描电镜下观察到金属离子Ni^(2+)和Cu^(2+)均匀地负载在白云石载体表面,白云石负载镍铜双金属后,催化剂的表面积和孔径均有所减小;建立催化热解反应动力学模型并求解动力学参数,当没有加入催化剂时,煤样在300~500℃热解段的活化能为96.3546 kJ/mol;加入白云石后,煤样的活化能下降至80.2132 kJ/mol。可见白云石对煤热解具有一定的催化效果。白云石负载镍基催化剂使煤热解活化能大幅度降低,仅为28.7431 kJ/mol。不同催化剂能有效地降低煤热解活化能,对内蒙古褐煤的热解有显著的促进作用。动力学分析结果与热重分析结果较好地吻合。因此,得出在活泼热分解阶段不同催化剂的催化效果为负载10%Ni/Cu(1∶0.2)-白云石>负载10%Ni-白云石>负载10%Ni/Cu(1∶0.5)-白云
Low rank coal is abundant,has low degree of coalification,high reactivity,,low utilization rate of direct combustion and high pollution,so it is hard to be made use fully.much research has been done on catalysts for coal pyrolysis,but it is rare to use nickel-loaded dolomite as catalysts for the catalytic pyrolysis of low-rank coal.In order to achieve the high-quality utilization of low-rank coal,Inner Mongolia lignite was studied.A nickel-based catalyst(Ni-dolomite)loaded by dolomite was prepared by equal volume impregnation and copper was added as co-catalyst.The effects of different catalysts on the pyrolysis process of Inner Mongolia lignitecarriedout by thermogravimetric(TG),the catalyst of best activity was scanned by electron microscope,and kinetics of the active pyrolysis stage was studied.The paper shows that the pyrolysis conversion rate of raw coal is 14.67%without catalyst added.The pyrolysis conversion of coal with 10%dolomite is 21.84%,which is 6.17%higher than that of raw coal.The results indicate that catalysts play a role in promoting coal pyrolysis and reducing the activation energy of pyrolysis,but the catalytic effects of different catalysts are different.However,the dolomite catalyst supported with Ni-Cu ratio of 1∶0.2 has the best catalytic effect on the pyrolysis of Inner Mongolia lignite,and the excessive Cu^(2+)will reduce the catalytic effect.Ni^(2+)and Cu^(2+)were uniformly distributed over the surface of the dolomite,and the surface area and pore size of the catalyst decreased after the dolomite was loaded with Ni^(2+)and Cu^(2+)by electron microscope scanning.The kinetic model of catalytic pyrolysis reaction was established and the kinetic parameters were calculated.When no catalyst was added,the activation energy of coal samples at 300-500℃was 96.3546 kJ/mol.With the addition of dolomite,the activation energy of coal samples decreases to 80.2132 kJ/mol,indicating that dolomite has a certain catalytic effect on coal pyrolysis.The results of kinetic analysis are in good agreement w
作者
马旭
刘萍
李文军
张海永
苏倩倩
MA Xu;LIU Ping;LI Wenjun;ZHANG Haiyong;SU Qianqian(China Chemical Safety Association,Beijing 100010,China;College of Environmental Engineering,North China University of Science and Technology,Sanhe 065201,China;China University of Mining and Technology-Beijing,Beijing 100080,China)
出处
《洁净煤技术》
CAS
CSCD
北大核心
2024年第S02期149-153,共5页
Clean Coal Technology
基金
中央高校基本科研业务资助项目(3142013097)
关键词
内蒙古褐煤
镍基催化剂
浸渍法
催化热解
动力学
Inner Mongolia lignite
Nickel-based catalyst
impregnation method
catalytic pyrolysis
kinetics
