Toshiaki Hisamitsu

Hydrorefining of Shale Oil. Part 6. Effects of Reaction Conditions on HDN Reaction and Catalyst Deactivation.

With the objective of studying the effects of reaction conditions on hydrodenitrogenation (HDN) reaction and catalyst deactivation, the whole shale oil used previously was hydrorefined over a Mo-Ni-P/Al2O3 catalyst under the following reaction conditions: reaction temperatures, 370, 390, and 410°C; reaction pressures, 70, 100, and 140kg/cm2; oil feed rates varying from 0.3 to 2.0 LHSV.The HDN reaction well follows a 1.3rd order reaction rate equation, irrespectively of the reaction conditions involved, and the activation energy is 27kcal/mol. It is confirmed that the increase in the reaction pressure not only accelerates the HDN reaction, but also suppresses catalyst deactivation. Reaction pressures above 100kg/cm2 have been found desirable to reduce the nitrogen content of the shale oil to around 500ppm level, which is considered to be an economically optimum level from industrial point of view. The nitrogen can be removed more selectively with less hydrogen consumption at lower reaction temperatures.

Hydrorefining of Shale Oil. Part 7. Long-period Bench Unit Tests.

Bench-unit tests on hydrorefining of the shale oil used in our previous work has been carried out over a Mo-Ni/Al2O3 catalyst in the first reactor and over a Mo-Ni-P/Al2O3 catalyst in the second reactor under the reaction conditions: 100kg/cm2; 0.67 LHSV; and 93% nitrogen removal (HDN), on the average, for 2, 700h.The shale oil was upgraded to a good-quality synthetic crude oil by hydrorefining. Hydrogen consumption was 210Nl/kg-oil at 90% HDN and 240Nl/kg-oil at 95% HDN.Arsenic in the shale oil was removed almost completely at 300°C in the first reactor. Deactivation of the second reactor catalyst was significantly accelerated at reaction temperatures above 390°C at 100kg/cm2.The experiment was forced to shut down three times due to the increase in the pressure drop through the first reactor, which indicated the importance of taking precautionary measures to avoid excess coke accumulation in the upstream catalyst bed.

Hydrorefining of Shale Oil (Part 5)

Hydrorefining of a certain shale oil has been carried out under rather mild reaction conditions, 150-350°C, 100kg/cm2, 2.0 LHSV, with the objective to study how to cope with the problems caused by coke formation in hydrorefining equipment and catalyst bed. As a result, the following conclusions have been drawn:1) Most of the unstable olefinic compounds present in the shale oil are removed by hydrorefining over a conventional Mo-Ni-Al2O3 catalyst at reaction temperatures in the range from 250 to 300°C.2) In the absence of a hydrorefining catalyst, shale oil should not be heated to such high temperature as 350°C even in hydrogen atmosphere to avoid significant coke formation.3) Reaction temperatures near 300°C are considered to be suitable for pretreatment of shale oil to selectively hydrogenate the unstable olefins and to remove the arsenic concurrently without causing significant coking problems.

Studies on Hydrodesulfurization of Heavy Distillates (Part 2)

Kinetic studies on hydrocracking (HC), hydrodesulfurization (HDS), and hydrodenitrogenation (HDN) reactions of vacuum gas oil derived from mixed Middle Eastern crude oils have been made. Hydroprocess experiments were carried out over a Co-Mo/Al2O3 catalyst at temperatures of 380, 400, and 420°C and at pressures of 4.0 and 7.9MPa. The HC and HDN reactions have been found to be of first order kinetics. However, the order of reaction for HDS reaction decreases with increasing temperature. The sensitivity of these reaction rates to pressure decreases in the following order: HDN>HDS>HC. In addition, with increase in temperature, the effect of pressure on the HC and HDS reaction rates decreases, whereas its effect on the HDN reaction rate is unvaried. These observations are interpreted by assuming that HC and HDS reactions follow at least two parallel reaction routes, which are differently influenced by pressure, and that the selectivity between the parallel reaction routes varies with temperature.

Hydrorefining of shale oils. Part 2. Kinetics of hydrodenitrogenation reactions.:Kinetics of Hydrodenitrogenation Reactions

茂名産シェールオイルの水素化精製において含有窒素を塩基性窒素, 酸性窒素, および中性窒素にタイプ分けし, それぞれの脱窒素反応速度について検討した。その結果, シェールオイルおよび石油のいずれの場合においても, 脱窒素のされやすさは中性窒素, 塩基性窒素, 酸性窒素の順であることが明らかとなった。また, 茂名産シェールオイルの灯軽油留分および減圧軽油留分における脱窒素反応は塩基性窒素, 酸性窒素および全窒素濃度について1次であり, 活性化エネルギーは全窒素の場合それぞれ, 約17kcal/mol, 約22kcal/molと求められた。