Study On Coke Formation And Conversion Process In In-situ Combustion

It is very important to understand the mechanism of coke burning in ISC.In this paper,through laboratory experiments,two different types of coke material composition and reaction characteristics of crude oil produced during the development of ISC were studied.The effects of oil composition,pressure,oxygen concentration and temperature gradient on the formation of coke were clarified.The two coke materials were analyzed by elemental analysis.TGA/DSC-1 was used to determine the activation energy of coke.The effects of different factors on the coking process were studied by experiments with different oil,different pressures,different oxygen concentrations and different heating rates.The coking rate under different experimental conditions was calculated.Finally,a one-dimensional physical simulation experiment is carried out to study the coking process of crude oil.The results show that the H/C ratio of Coke₁ is in the range of 0.49⁰.62,O/C is in the range of 0.38⁰.48,the H/C ratio of Coke₂ is in the range of 1.33¹.43 and the range of O/C is 0.193⁰.198.The hydrogen content in Coke₂ is 2.42 times the hydrogen content in Coke₁,and the oxygen content in Coke₁ is 2.32 times the oxygen content of Coke2.The activation energy of Coke1 is 150.48kJ/mol,and the activation energy of Coke₂ is 112.65kJ/mol.In the study of the influence of reaction conditions on the coking process,the results show that the factors such as oil characteristics,oxygen concentration,reaction pressure and heating rate all contributed to the coking of crude oil to a certain extent.In the one-dimensional physical simulation experiment,the coke is more close to the actual mine fire condition.Combined with the results of the basic analysis experiment,it can be deduced that both Coke1 and Coke2 may exist in the actual fire driving process.Experiments show that most of the crude oil can be driven out.Flooding efficiency of up to 90%or more.