生物炭模板构筑Fe-Ni复合载氧体及其化学链制氢反应性能研究

摘要

Fe-Ni oxygen carriers(Fe-Ni/BC) were prepared by using pine biochar as a template,and compared with NiFe2O4oxygen carriers synthesized by sol-gel method. The obtained oxygen carriers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area measurement, hydrogen-temperature programmed reduction (H2-TPR),and thermos-gravimetric redox-cycling (TG-redox). Furthermore, the performance of chemical looping hydrogen generation was investigated in a fixed-bed reactor. The results show that the prepared Fe-Ni/BC is a mixed crystal of Ni0.6Fe2.4O4and Fe2O3,retaining the framework of biochar and having a macroporous structure. Fe-Ni/BC outperforms NiFe2O4/SG in oxygen release, because of small average particle size, high specific surface area and abundant surface absorbed oxygen. In the fixed-bed tests,Fe-Ni/BC exhibits a better capability of hydrogen production and anti-carbon deposition with the maximum rate of hydrogen production for Fe-Ni/BC, 1.58 times that for NiFe2O4/SG, and the relative concentration of H2produced by Fe-Ni/BC is more than 99.5%.%采用松木热解生物炭为模板构筑Fe-Ni复合载氧体((Fe-Ni/BC),并与溶胶-凝胶法制备的NiFe2O4载氧体(NiFe2O4/SG)对比,采用SEM、XRD、XPS、BET、H2-TPR、TG-redox循环等表征方法考察载氧体的物理、化学性质,并在固定床上进行化学链制氢循环实验.结果表明,Fe-Ni/BC载氧体为Ni0.6Fe2.4O4与Fe2O3的混合晶体,保留了生物炭骨架并形成了大孔结构.与NiFe2O4/SG相比,Fe-Ni/BC平均粒径更小,比表面积更大,吸附氧含量更高,更有利于氧的释放.在固定床实验过程中, Fe-Ni/BC表现出更强的化学链制氢与抗积炭性能,其最大产氢速率是NiFe2O4/SG的1.58倍,制取H2的相对浓度可达到99.5%以上.