镍基催化剂的制备及其对垃圾气化产氢的催化活性

Preparation of Ni-based catalysts and evaluation of their catalytic activity in gasification of municipal solid waste(MSW) to hydrogen

以陶粒为载体,采用常温浸渍法制备了负载型镍基催化剂,并利用X射线衍射分析(XRD)、X射线荧光分析(XRF)、BET、环境扫描电镜-能谱仪分析(ESEM-EDX)和元素分析等对其进行了表征,该催化剂BET表面积为101.3m2/g.活性组分NiO颗粒平均粒径约为2μm,均匀分散在载体表面.并在下吸式固定床气化炉中,进行水蒸气催化气化城市生活垃圾有机组分的实验来评价镍基催化剂的催化活性.结果表明,在镍基催化剂的作用下,H2和CO含量明显增加,H2含量最高达43.22%,CO2、CH4、C2H4和C2H6.平均含量降至1%以下.催化气化过程的产氢率远远高于气化过程,最高达19.9mol H2/kg,低温段催化气化的潜在产氢率高于气化过程,但高温段低于气化过程;高温有利于气化产气中H2和CO的生成,还可以促进CH4、C2H4和C2H6的分解.催化气化过程的焦油产率、灰渣产率明显低于气化过程,特别是焦油产率降至2%以下,而产气率则高于气化过程.

Ni-based catalysts were prepared with ceramsite as carrier by the method of impregnation,and characterized using X-ray diffraction（XRD） ,X-ray fluorescence（XRF） ,BET,environmental scanning electronic microscope-energy dispersive X-ray（ESEM-EDX） and elemental analysis. Ni-based catalysts have a specific surface area of 101.3m2/g. The active components of catalysts were spherical NiO particles coated on the surface of supports in a mean size range of about 2μm. Furthermore,evaluation of catalytic activity of the Ni-based catalysts used in MSW steam gasification was also investigated in a bench-scale downstream fixed bed reactor. The experiments demonstrated that in the presence of Ni based catalysts H2 and CO contents significantly increased,while CO2,CH4,C2H4 and C2H6 contents decreased. H2 yield in catalytic gasification process was greater than that in gasification process at lower temperature,the potential H2 yield for catalytic gasification process was greater than that in gasification process,but less at higher temperature. Higher temperature favored formation of H2 and CO,and decomposition of CH4,C2H4 and C2H6. Meanwhile,tar yield and char yield for catalytic gasification process were significantly less than for gasification process,but gas yield was greater under the same conditions.