Phenanthrene Hydrogenation Over NiW/Al₂O₃Catalyst And The Influences Of Sulfide And Nitride

With the growing oil depletion, the demand for clean fuel is increasing at different countries. Shale oil and coal tar are expected to become the most promising substitute, but they have high contents of S, N and aromatic compounds. The high content of aromatic in fuel will reduce the combustion properties; pollute environment by produced harmful solid particles. Due to increasingly stringent environments regulations, it is important to removal the aromatics in oil. Hydrodearomatization is the primary means to reduce the content of aromatic in oil. The content of phenanthrene in coal tar is4-5%, just blower than naphthalene (10%). The phenanthrene is an important industrial raw material, the intermediate products of phenanthrene hydrogenation can be used as hydrogen donor for coal liquefaction, and the perhydrophenanthrene can be used as jet fuel. So it can promote the rational use of resources by studying the mechanism of phenanthrene hydrogenation and adjusting the selectivities of hydrogenation products.The thesis investigated phenanthrene and its intermediates hydrogenation on NiW/Al2O3catalyst in a continuous-flow tubular microreactor, it is found that the products just included dihydrophenanthrene (DHP), tetrahydrophenanthrene (THP), asym-octahydrophenanthrene (1,10-OHP), sym-octahydrophenanthree (1,8-OHP) and perhnydrophenanthrene (PHP), without cracking products. The effects of operating conditions on phenanthrene hydrogenation were tested in detail. It is found that the optimum reaction temperature of phenanthrene hydrogenation on NiW/Al2O3catalyst was340°C, high pressure raise phenanthrene conversion, the optimum H2/liquor ratio was500-700(mL/mL). The mutual influence of phenanthrene and naphthalene hydrogenation was also studied, it seemed that naphthalene had negligible effects on phenanthrene hydrogenation; phenanthrene hindered naphthalene hydrogenation. Decalin dehydrogenation could produce tetralin and naphthalene, hydrogen released by decalin could promote phenanthrene hydrogenation and improve the yield of perhydrophenanthrene.The effects of thiophene on phenanthrene, dihydrophenanthrene hydrogenation showed that:the rate of thiophene hydrodesulfurization was faster than the rate of phenanthrene hydrogenation, and thiophene hindered phenanthrene hydrogenation. The inhibition effect of thiophene on phenanthrene was stronger at low temperature and pressure, and weakened with the increase of temperature and pressure. Thiophene inhibited dihydro-phenanthrene hydrogenation and promoted dehydrogenation. when the content of thiophene was small in raw materials, the inhibition effect of thiophene was weakened by increasing the reaction temperature and pressure and prolonged contact time.To investigate the influence of quinoline, it is found that the competitive adsorption of quinoline hindered phenanthrene hydrogenation. The generation of dihydrophenanthrene was more be inhibited than generation of tetrahydrophenanthrene. Prolonging contact time and increasing temperature could increase the conversion of phenanthrene, but could not reduce the inhibition effect of quinoline on intermediate products of phenanthrene hydrogenation or increase the content of perhydrophenanthrene. Quinoline hindered dihydrophenanthrene hydrogenation and promoted dehydrogenation to phenanthrene. When quinoline was in solution, adding a small amount of thiophene weakened the inhibition of quinoline.