The effects of dispersed catalyst and hydrogen donor on the cracking and cracking selectivity of characteristic model compounds in residue oil, such as N-eicosane, butyl benzene and 1,6-diphenylheptane, were investiga...The effects of dispersed catalyst and hydrogen donor on the cracking and cracking selectivity of characteristic model compounds in residue oil, such as N-eicosane, butyl benzene and 1,6-diphenylheptane, were investigated in the thermal, hydrothermal and catalytic hydrocracking systems at 440?℃. The three compounds had different cracking characteristics. N-eicosane had the simplest bond-scission way. The bond-scissions of butyl benzene in the thermal system were mainly β- and γ- bond-scission, while β- in hydrothermal and α- bond-scission in catalytic hydrocracking were main reactions. 1,6-diphenylheptane had more complex cracking ways, which were α-, β-, homolysis and γ-bond-scission. The bond-scissions of 1,6-diphenylheptane in thermal cracking underwent such four ways, how-ever, α- and β-bond-scission or α-bond-scission were main reactions in hydrothermal or in catalytic hydrocracking of 1,6-diphenylheptane, respectively. It seems that these three model compounds experienced the radical reaction in the single systems of model compounds or in the binary system of model compounds/tetralin for thermal, hydrothermal and catalytic hydrocracking. Molecular hydrogen as well as dispersed catalyst enhanced the cracking of model compounds, while H-donor depressed the cracking. For cracking selectivity of the three compounds, thermal and hydrothermal cracking were the basis of other processes and dispersed catalysts clearly affected the cracking selectivity of alkyl aromatics. On the other hand, hydrogen donor had influence on a certain extent on the cracking selectivity on the basis of the thermal, hydrothermal and catalytic hydrocracking systems.展开更多
Hydrogenation of 2-ethylanthraquinone is a key step in the industrial production of hydrogen peroxide via anthraquinone. This reaction on palladium-supported catalysts is normally carried out in trickle-bed reactors. ...Hydrogenation of 2-ethylanthraquinone is a key step in the industrial production of hydrogen peroxide via anthraquinone. This reaction on palladium-supported catalysts is normally carried out in trickle-bed reactors. A numerical model for simulation of a gas-liquid-solid hydrogenation trickle-bed reactor is presented. The model is based on the film theory and takes into account the axial dispersion effect on the performance of the reactor. Comparison of calculated values with data from pilot plant and industrial reactor shows that the agreement is quite satisfactory and the maximum variance is less than 5%. Gas-liquid and liquid-solid mass-transfer coefficients are determined by semi-empirical correlations available in the literature. The palladium-supported catalyst is extremely active and the reaction is always controlled by gas-liquid mass-transfer, and the overall effectiveness factor is always very low in agreement with the high catalytic activity of the palladium-supported catalyst.The overall effectiveness factor increases with decreasing catalyst hold-up. Therefore, it is feasible to improve the productivity of unit catalyst by decreasing the catalyst hold-up in a commercial plant with the hydrodynamic characters kept unchange.展开更多
文摘The effects of dispersed catalyst and hydrogen donor on the cracking and cracking selectivity of characteristic model compounds in residue oil, such as N-eicosane, butyl benzene and 1,6-diphenylheptane, were investigated in the thermal, hydrothermal and catalytic hydrocracking systems at 440?℃. The three compounds had different cracking characteristics. N-eicosane had the simplest bond-scission way. The bond-scissions of butyl benzene in the thermal system were mainly β- and γ- bond-scission, while β- in hydrothermal and α- bond-scission in catalytic hydrocracking were main reactions. 1,6-diphenylheptane had more complex cracking ways, which were α-, β-, homolysis and γ-bond-scission. The bond-scissions of 1,6-diphenylheptane in thermal cracking underwent such four ways, how-ever, α- and β-bond-scission or α-bond-scission were main reactions in hydrothermal or in catalytic hydrocracking of 1,6-diphenylheptane, respectively. It seems that these three model compounds experienced the radical reaction in the single systems of model compounds or in the binary system of model compounds/tetralin for thermal, hydrothermal and catalytic hydrocracking. Molecular hydrogen as well as dispersed catalyst enhanced the cracking of model compounds, while H-donor depressed the cracking. For cracking selectivity of the three compounds, thermal and hydrothermal cracking were the basis of other processes and dispersed catalysts clearly affected the cracking selectivity of alkyl aromatics. On the other hand, hydrogen donor had influence on a certain extent on the cracking selectivity on the basis of the thermal, hydrothermal and catalytic hydrocracking systems.
基金国家重点基础研究发展规划项目 (No 2 0 0 0 0 480 0 5 )国家自然科学基金项目 (No 2 0 10 60 11)化学工程国家重点实验室资助~~
文摘Hydrogenation of 2-ethylanthraquinone is a key step in the industrial production of hydrogen peroxide via anthraquinone. This reaction on palladium-supported catalysts is normally carried out in trickle-bed reactors. A numerical model for simulation of a gas-liquid-solid hydrogenation trickle-bed reactor is presented. The model is based on the film theory and takes into account the axial dispersion effect on the performance of the reactor. Comparison of calculated values with data from pilot plant and industrial reactor shows that the agreement is quite satisfactory and the maximum variance is less than 5%. Gas-liquid and liquid-solid mass-transfer coefficients are determined by semi-empirical correlations available in the literature. The palladium-supported catalyst is extremely active and the reaction is always controlled by gas-liquid mass-transfer, and the overall effectiveness factor is always very low in agreement with the high catalytic activity of the palladium-supported catalyst.The overall effectiveness factor increases with decreasing catalyst hold-up. Therefore, it is feasible to improve the productivity of unit catalyst by decreasing the catalyst hold-up in a commercial plant with the hydrodynamic characters kept unchange.
