Aquathermolysis Of Thick Oil Catalyzed By Clay-Transition Metal Coordination And Mechanism Study

The complex environment,high viscosity and poor mobility of thick oil formations make their extraction difficult.The current research on hydrothermal cracking catalytic viscosity reduction technology is only limited to the introduction of exogenous catalysts or the influence of in situ minerals of the formation on the reaction viscosity reduction efficiency,without considering the reaction between exogenous catalysts introduced and in situ minerals of the formation to form stable complexes,which jointly cooperate to catalyze the hydrothermal cracking reaction of thick oil.Therefore,this paper adopts the stable complexes prepared by exogenous and endogenous minerals to hydrothermal cracking reaction of thick oil,optimizes the reaction conditions,investigates the mechanism of catalytic viscosity reduction reaction,and provides theoretical support for the application of hydrothermal cracking catalytic viscosity reduction technology.The optimum reaction conditions were determined as follows: reaction temperature180 ℃,reaction time 4 h,water addition 30%,mineral type sodium montmorillonite,mineral addition 0.2%,and the viscosity reduction rate of oil samples could reach 23.8% after the reaction.A series of transition metal complexes were synthesized with glycine and piperazine as ligands,and the endogenous and exogenous complexes were characterized by IR,thermogravimetric and SEM analyses to investigate the catalytic effect of the composite catalysts on the viscosity reduction reaction of hydrothermal cracking of oil samples.The S@Ni(Ⅱ)P composite catalyst had the best viscosity reduction catalytic effect on Henan oil sample with 67.5 % viscosity reduction rate.After that,methanol was introduced as the hydrogen coagent of S@Cr(Ⅲ)G composite catalyst system,and the catalytic effect of methanol and S@Cr(Ⅲ)G on hydrothermal cracking reaction was investigated,and the viscosity reduction effect could reach 78.8 %;ethanol was introduced as the hydrogen coagent of S@Ni(Ⅱ)P composite catalyst system,and the catalytic effect of ethanol and S@Ni(Ⅱ)P on hydrothermal cracking reaction was investigated,and the viscosity reduction effect could reach 88.3 %.The viscosity reduction effect could reach 88.3 %.The thermogravimetric analysis,gas chromatography analysis,elemental analysis and differential scanning calorimetry analysis of Henan oil samples before and after the reaction showed that some of the hard-to-decompose components in the oil samples were converted into lighter components,the content of lighter components increased,the solubility of waxes in the oil samples increased,the waxing point decreased,the content of heteroatoms such as N and S in the oil samples decreased,and the content of low carbon hydrocarbons in saturated hydrocarbons increased.Finally,six model compounds of benzothiophene,thiophene,phenol,nonylphenol,quinoline and pyridine were selected to simulate some functional groups in the oil samples for hydrothermal cracking catalytic reaction,and the products were analyzed by GC-MS.The reaction mechanism of hydrothermal cracking viscosity reduction reaction of thick oil was further clarified by the removal of nitrogen atoms from quinoline and the formation of ammonia and cycloalkanes.