Experimental Study On The Aquathermolysis Mechanism For Thiophene

Because of heavy oil steam injection thermal recovery process of sulfur compounds and mineral formation and high temperature steam happened between complex thermochemical reaction to generate large amounts of H2S gas,and the sulfur in heavy oil and petroleum products is mostly in form of hydrocarbon derivatives,therefore,the reaction law of organic sulfur compounds has great influence on the change of heavy oil properties,In order to study the aquathermolysis reactions of complex heavy oils,it is shown through the study of typical model compounds in heavy oils,which is of great significance for the modification of heavy oil and the desulfurization of sulfur compounds.In this paper,thiophene was selected as the model compound,The experiments of thermal cracking and aquathermolysis were carried out in the reaction kettle of high temperature and pressure,and then a series of experiments were carried out to investigate the effects of reaction conditions such as reaction temperature,reaction time and pH value on aquathermolysis of thiophene,finally,the gas products and liquid products were tested after the reaction.There are more CO2,H2S and light hydrocarbons in the gas phase products of thiophene aquathermolysis,and the number of H2 and CO is less.The main hydrocarbon products of aquathermolysis of thiophene are methane and butane,in addition to a large number of unreacted thiophene,liquid products include very small number of alkylthiophene,thienylthiophene,dihydrothienylthiophene and alkyldihydrothienylthiophene.The gas phase products of thiophene thermal cracking are H2S,H2 and light hydrocarbon,and the liquid products include a large number of unreacted thiophene,also include very small number of thenylmercaptan,tetrahydrothiophene,alkylthiophene and thienylthiophene derivatives.Based on gas phase products and liquid phase products,the reaction pathway of thermal cracking and aquathermolysis of thiophene were discussed.Protonation,primary hydrolysis and secondary hydrolysis play an important role in the formation of H2S.The cleavage of the C-S bond is an important step in the aquathermolysis and thermal cracking reactions of thiophene.In a certain range,the degree of aquathermolysis reaction of thiophene is positively correlated with the reaction temperature and reaction time.Under the low pH value,the aquathermolysis of thiophene is faster,and the reaction is more likely to occur,the high pH value is not conducive to the aquathermolysis reaction of thiophene.The experiment of aquathermolysis between thiophene and metal salts,the selection of Al³⁺,Ni²⁺,Mg²⁺,Ca²⁺and Zn²⁺,these five kind of metal ions of thiophene aquathermolysis has obvious catalysis,Al³⁺ions have the best catalytic effect,in a certain range,The higher the concentration of metal ions,the more obvious the catalytic effect of metal ions on aquathermolysis of thiophene.Finally passed the dynamic experiment between thiophene and water,The kinetic parameters of H2S were obtained from each reaction system:The apparent activation energy of H2S by aquathermolysis of thiophene is 57.31kJ/mol,The apparent activation energy of H2S by the reaction of Magnesium chloride and thiophene is 24.38 kJ/mol,The apparent activation energy of H2S by the reaction of aluminium chloride and thiophene is 17.18 kJ/mol,The apparent activation energy of H2S by the reaction of nickel chloride and thiophene is 22.33kJ/mol.