| Ammonia is one of the most basic chemical raw materials in the world. Industrially, nitrogenous fertilizer and organonitrogen compounds fundamentally depend for their nitrogen source on NH3 produced by Haber-Bosch process. The Fe1-xO-based catalyst for ammonia synthesis was invented by professor Liuhuazhang in 1986, which has many advantage such as high activity and easy reduce etc. We all know that the Wustite structure is non-stoichiometric ferrous oxide, and there are tetrahedron and octahedron interspace formed by oxygen anion cubic closest packing. So there are structural advantage for doping and modification the Fe1-xO aim at producing catalyst which has the highest catalytic performance. In this thesis, the effect of metal promoters on catalytic performance of Fe1-xO-based catalyst for ammonia synthesis was investigated. Also, the preparation methods of catalyst and the intrinsic reaction kinetic of ammonia synthesis were studied.Firstly, the study on the effect of W, Ti, Ni, Ta and Mo promoters on the activity of Fe1-xO-based catalyst was carried out. Also, the influence of single metal, double metals and metal oxide promoter on catalytic performance was compared. It was found that metal W can remarkably increase the activity at low temperature and enhance heat-resistance, XRD characterization indicated that tungsten exist in the catalyst in the form of WO2.9. The electron transfer from the non-stoichiometric compound WO2.9 to -Fe atom might occur at the condition of ammonia synthesis. It is due to such an interaction that the electron densities of the -Fe is increased. The adulteration of Ti or Ni can increase the catalytic activity at low temperature to some extent, but it will result in the form of Ca3(AlO3)2 phase in the catalyst when titanium is excessive, and the result is the activity descended rapidly. While adulteration of Ta will decrease the activity a little and Mo will sharply decrease the activity. In the scope of this thesis, the effect of double metals such as W, Ti or W, Ni promoters and metal oxide promoter on catalytic performance is not as efficiently as that of single metal promoter such as W. As for catalyst doped with WO3, XRD characterization show that there are WO2.9 exist inthe catalyst .At the same time, some W enter into the Fe].xO lattice through replace Fe3+ in the Fe1.xO lattice. This is the reason why the activity of catalyst doped with WO3 decreased after overheating. There are exist strong-interaction between the oxidisability of doped-metal and the contents of K, the contents of K should increase to obtain high activity when the oxidisability of metal is strong. The suitable contents of metal promoter are very little only about 0.5% by weight. The different in precursor of promoter can make great distinctness on catalytic performance for the melting process is very complicated.Secondly, the effect of prepare methods on catalytic activity was investigated. The results is the cooling rate is very important on the form and growth of crystal and the uniform distribution of promoters, the rapid cooling rate is helpful for improve the catalytic activity. At the same time, the selected reducer should participate the reduction efficiently and obtain pure Fe1_xO as precursor. Through adjusting the ratio of magnetite and reducing agent, the molten iron catalysts with different chemical composition are prepared.Thirdly, the intrinsic kinetics of catalyst AT01 for ammonia synthesis was studied. The catalytic activity of AT01 was obtained under the resistance of internal and external diffusion. The Temkin kinetics model were examined and obtained the linear equation by fit the experimental data at different a valence. And further more obtained the rate constant and activity energy. The result indicated Temkin-Pyzhev kinetics equation expressed by partial pressure is suitable for AT01 catalyst in a wide variety of temperature, and the suitable valence fora is 0.50 when temperature high than 400 and 0.40 when temperature low than 400 .Lastly, the effect of reaction...
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