Experiment And Simulation On Temperature Field During Oil Shale Pyrolysis By Electric-heating

We human beings can not survive without coal, oil and natural gas. Withthe rapid development of world economy recently, the reserves reducedsharply. According to the survey to the world’s energy reservessituation by international energy, the energy can be used for no more than100years at current exploitation speed.Therefore, it is necessary tofind a new alternative energy source to supply the world’s futuredevelopment.Although the oil shale in-situ mining technology has obviousadvantages, it also has many problems. That is why it has still notbeen large-scale promotion. This paper studies oil shale’s physicsproperties and thermal physical properties with time by experiment. Thephysics properties include density, moisture and void ratio. The thermalphysical properties include thermal conductivity, thermal diffusivityand specific heat. The relationship between crack of oil shale gas isanalysed. The temperature field is studies while the oil shale isheating. On this basis, the finite element software is used to simulatethe temperature in the process of oil shale electric heating test. Theresult of simulation is fitted to test result. The finite elementsoftware is also used to simulate the temperature field in actual site.The results are as followings:1. With the increase of heating temperature, the bulk density of theoil shale has been declining. The change particle density and voidratio with temperature is divided into3stages:①from normalatmospheric temperature to450℃stage, with the particle densitydecreasing and void ratio increasing:②450～520℃satge, particledensity and void ratio both sicreasing;③520～750℃stage, particledensity increasing and void ratio remaing unchanged. 2. Thermal physical properties of oil shale are anisotropic. Heatconduction coefficient and specific heat of vertical stratification isless than parallel bedding, while thermal diffusion coefficient is onthe contrary.3. The main gas produced in the process of oil shale pyrolysisis CH4、C2H6、H2S、C4H10、C5H12and C4H8. In the low temperature stage, kerogenis split into unsaturated hydrocarbon—C4H8.With the increase oftemperature, and the content of H2S and alkane increase.4. Indoor simulated in situ heating temperature field testshows that, in early stage the temperature of oil shale is related tothe nearest heater. That is, the nearer with heater, the highertemperature it is. With the extension of time, the cumulative effecton the heater heat can not be ignored. The temperature of fartherdistance with heater may exceed the nearer.5. The finite software ANSYS is used to simulate temperature fieldof HuaDian oil shale electric heating processing with different power.The results showed that, of6heating well mode with spacing5m,2kW heater power is better. Oil and gas extraction time is4～6years after heating.