Research On The Carbon Deposition Characteristics Of Cycle Gas In The Oil Shale Retorting Process

The characteristics of retorting gas carbon deposition is carried out underdifferent temperature(600℃,650℃,700℃,750℃), different reaction times(30min,60min) and different gas flow(10ml/min,20ml/min) conditions in the stainless steeltube reactor of06Cr25Ni20in a home-made continuous flow reactor system. Thetemperature range of the initial carbon deposition which is obtained through multiplesets of experiments is450℃~470℃.The morphology of the carbon deposition is analysised through temperatureprogrammed oxidation methods(TPO) and scanning electron microscopy, the resultsof the analysis show that there are two different species of coke in the carbondeposition including amorphous carbon and filamentous coke; the carbon depositionamount of the retorting gas in the reactor is analysised by isothermal oxidationmethod under different conditions, the results show that when the reaction times andthe gas flow are constant, the carbon deposition amount increases with the increase ofthe wall temperature; when the wall temperature and the gas flow are constant, thecarbon deposition amount increases with the increase of the reaction times; when thewall temperature and the reaction times are constant, the carbon deposition amountincreases with the increase of gas flow. The corresponding carbon deposition rate iscalculated by carbon deposition amount, the trends has a slight difference comparedwith the carbon deposition amount that when the wall temperature and the gas floware constant, the carbon deposition amount decreases with the increase of the reactiontimes.Using the Arrhenius equation, the rate of carbon deposition is associated withthe reciprocal of reaction temperatures, and the global activation energy of retortinggas carbon deposition under defferent conditions(10ml/min,30min;20ml/min,30min;10ml/min,60min;20ml/min,60min) are got. Namely,45.187kJ/mol,33.214kJ/mol, 40.788kJ/mol,32.732kJ/mol. The results show that when the gas flow and thereaction times are smaller, the carbon deposition is formed at a higher temperature.Meteorological chromatograph is used for analysis of the gas composition beforeand after different experiments. The results of the analysis show that the mainmaterial for carbon deposition are the small molecule olefins; the factors influencingretorting gas carbon deposition are analysed through intuitive analysis method andmultiple factor mixed level variance analysis method. The results show that thereaction times affect retorting gas carbon deposition the most.