NiO-Fe_2O_3/PG-γ-Al_2O_3催化剂的制备及其在秸秆热解中的应用

Preparation of NiO-Fe _2O_3/PG-γ-Al_2O_3 catalysts and its application in pyrolysis of biomass straw

通过沉积沉淀法与均匀沉淀法制备以坡缕石与伽马氧化铝(Palygorskite-Gamma Alumina,PG-γ-Al_2O_3)为复合载体的负载型NiO-Fe_2O_3/PG-γ-Al_2O_3催化剂,采用了EDX、XRD、SEM、N2等温吸附-脱附等手段对催化剂进行了表征与分析。同时利用管式炉考察了NiO-Fe_2O_3/PG-γ-Al_2O_3催化剂在作物秸秆热解中的催化性能和再生使用寿命及抗积炭能力,并与两种单载体催化剂(NiO-Fe_2O_3/PG,NiO-Fe_2O_3/γ-Al_2O_3)进行了比较。结果表明,PG-γ-Al_2O_3复合载体比表面积达134.21 m2/g,平均孔径为39.65 nm。NiO-Fe_2O_3/PG-γ-Al_2O_3催化剂活性组分负载均匀,分散较好且催化剂中同时存在镍铁合金与镍铝尖晶石结构。催化剂活性测试显示,NiO-Fe_2O_3/PG-γ-Al_2O_3催化剂用于作物秸秆热解具有极高的催化活性,能够显著提高产品燃气品质、燃气中的CO与H2含量和燃气热值;相比单载体催化剂其催化活性好,再生效果佳,抗积炭能力较强。

The supported NiO-Fe2O3/Palygorskite and Gamma Alumina（NiO-Fe2O3/PG-γ-Al2O3） catalysts were prepared by deposition-precipitation and homogeneous-precipitation methods using PG-γ-Al2O3 as a carrier,and different approaches including EDX,XRD,SEM and N2 isothermal adsorption-desorption were used to characterize the synthetic catalysts. Meanwhile,the catalytic pyrolysis of biomass straw was conducted to test the catalytic activity,the regenerative service life and the anti-carbon capacity of NiO-Fe2O3/PG-γ-Al2O3 catalyst in a tube furnace,and to compare with the catalytic properties of single carrier catalysts. The results indicate that the prepared PG-γ-Al2O3 carriers have a high specific surface area of 134. 21 m2/g and the average pore size is39.65 nm. The active components are loaded uniformly and in a good dispersion over NiO-Fe2O3/PG-γ-Al2O3 catalyst,meanwhile,the Ni-Fe alloy and the nickel-aluminum spinel structure exist simultaneously in the catalyst. The catalytic activity testing shows that the NiO-Fe2O3/PG-γ-Al2O3 catalysts have a very high catalytic activity in pyrolysis of biomass straw. It could obviously improve the quality of the gas such as the content of H2 and CO and the calorific value. The catalytic activity,regeneration effect and anti-carbon deposition ability of NiO-Fe2O3/PG catalyst are better than that with single carrier catalyst.