Study On Desulfurization And Denitrification Reaction Mechanism Of Hydrogen Catalytic Cracking In Heavy Oil Combustion

In-situ combustion?ISC?is a upgrading technology developed to improve the recovery rate of heavy crude oil and asphalt.In the process of ISC,coke is formed by thermal cracking to maintain the continuous combustion of the combustion front edge.In this paper,the crude oil properties of the heavy oil were analyzed,the Ni-Fe-based catalyst was prepared,and the hydrogen donor and catalyst concentration were optimized.In the experiment,it was found that the upgrading effect was better when the catalyst concentration was 1wt%.In the experiment,H₂O,tetrahydronaphthalene,dechydronaphthalene and formic acid were used as hydrogen donors respectively.By comparing the TG/DTG curves and the upgrading effects of different hydrogen donors,it can be seen that the best upgrading effects were tetrahydronaphthalene,followed by dechydronaphthalene,formic acid and H₂O,respectively.Thermal analysis of crude oil is an important means to study the oxidation of crude oil.In this paper,TG/DTG obtained by thermal analyzer is used to divide the oxidation stage of crude oil into distillation stage,low-temperature oxidation stage,fuel deposition stage and high-temperature oxidation stage,and the temperature range of the four stages under different experimental conditions is divided.It is found that the oxidation process of crude oil under hydrogen catalysis is accelerated and the oxidation reaction is more intense.In the experimental study on the effect of hydrogen supply catalysis on the oxidation rate of crude oil,it was found that the oxidation rate of crude oil increased greatly after adding catalyst and hydrogen supply,and the oxidation rate of high temperature was higher than that of fuel deposition and low temperature.To study the influence of different experimental conditions on heavy oil upgrading is an important means to improve the oil recovery rate.According to the indoor tube furnace experiment,the viscosity,non-hydrocarbon content,sulfur content and nitrogen content of heavy oil all decrease to different degrees with the increase of temperature,while the content of saturated hydrocarbon and aromatic hydrocarbon increases.Moreover,temperature has a great influence on viscosity,and the addition of ni-fe-based catalyst and tetrahydronaphthalene has a great influence on desulfurization rate and denitrification rate.At last,the change of chemical bond and free radical in the process of pyrolysis was studied,and the mechanism of action of catalyst and hydrogen donor on heavy oil was revealed.