关键词: 化学链制氢（CLH）, 溶胶-凝胶法, NiFe₂O₄载氧体, 正交实验

Abstract:

NiFe2O4 oxygen carriers were prepared by the sol-gel method and used in chemical looping hydrogen (CLH). The effects of preparation parameters, such as the molar ratio of citric acid to metal ions (RCAMI), solution pH value and gelation temperature, on physicochemical properties and CLH performance of oxygen carriers were investigated by orthogonal experiments. Experimental results indicate that the CAMIR is the main factor to form the spatial structure of precursor， which affects the crystal phase， specific surface area and CLH performance. The solution pH value is related to the hydrolytic polycondensation of citric acid complex， which affects the purity of H2 product by strengthening or inhibiting the carbon deposition of CH4 in reaction process of biomass pyrolysis gas. The increase of gelation temperature can enhance the nucleation rate of precursor， but it will lead to the instability of sol， affecting the crystal structure and specific surface area of oxygen carrier subsequently. Lower gelation temperature is conducive to the release of lattice oxygen. The optimized preparation conditions of NiFe2O4 oxygen carriers for CLH are as follows: RCAMI of 1， pH value of 7 and gelation temperature of 60 ℃ with maximum H2 purity nearly 100% in CLH process.

Key words: chemical looping hydrogen(CLH), sol-gel method; NiFe₂O₄ oxygen carrier, orthogonal experiment