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

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。

Preparation of NiO-Fe2O3/PG-γ-Al2O3 catalysts and its application in pyrolysis of biomass straw

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 is 39.65 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.