Study Of Catalytic Conversion Of Methane To Synthesis Gas Reaction Process

It is well know to all of us that the present air pollution situation is a very serious problem in current China. Especially the haze phenomenon which is main because of the energy structure dominated by coal. Therefore, changing the energy structure and cleaning coal resources are extremely urgent fast approaching. Natural gas can be obtained by syngas methanation which derives from coal gasification. And in industrial practice, there is often a multistage reactor, after the first period of reaction product with raw gas directly into the response of a device. It contains certain content of entrance gas reactor under a section of the water vapor in the CO?. Research now shows a water vapor content generation can inhibit the carbon deposition, but too high content of water vapor can cause structural damage of carrier. The literature of methane in methane CO and CO2 reaction is a competing reaction. The current literature there is little stability experiment as raw gas containing a certain amount of water vapor and CO2. In this paper the catalytic conversion of synthesis gas to methane reaction process as the core research content, long time stability of the industrial environment simulation of methanation catalyst, to understand the effects of water vapor and CO2 on the catalyst of methanation.In this paper, we adopt industrial molding raschig rings and clover gamma-Al2O3 as carrier. Prepared with different NiO loading amount, different additives and different additive contents by impregnation method to make a series of catalysts. Using quartz fixed bed reactor to performance catalysts’evaluation. Characterize the catalysts’structure by XRD, TPR, BET, TEM, TG and so forth.We find that the optimum content of NiO is 18.7% and 26.1% by loading different contents of NiO (7.5%,11.2%,18.7,26.1%,37.4%, and 44.8%) onto industrial molding rasching ring carrier. With different additives added to the carrier, alkaline earth metal oxides (MgO, CaO, BaO), rare earth metal oxides (La2O3, CeO2,Sm2O3) and transition metal oxides (Fe2O3, CoO, CuO, ZrO2, TiO2, MoO3), we find that additives can improve the activity of the catalysts, among which MgO is the optimum alkaline earth metal oxides and La2O3 is the optimum rare earth metal oxides. We manufacture a series of Ni-based catalysts which are modified with Mg, La. We select 26.1%NiO-6.4% La2O3/MgAl2O4@Al2O3(BL) (4.1%MgO) as the optimal catalyst after activity evaluation under water phenomenon. The reaction become active at 200℃, the conversion rate of CO reached 100%, the selectivity of CH4 reached 99.05%, under the phenomenon without water. The reaction become active at 220℃, the conversion rate of CO reached 100%, the selectivity of CH4 reached 98.12%, under the phenomenon with 25vol% water in reaction gases. After 1572 hours continuous stability reaction, the catalyst can still performance well. That is to say that this catalyst has a very broad prospect in industry.We find that the optimum content of NiO is 26.1% by loading different contents of NiO (7.5%,11.2%.18.7,26.1%,37.4%, and 44.8%) onto industrial molding clover carrier. We use MgO to modify the carrier and eventually get the 26.1%NiO/MgAl2O4@Al2O3(BL)(4.1%MgO) catalyst. Under the phenomenon has V(H2):V(CO):V(CO2)= 110:22:7.7 in reaction gases, the catalyst’s performance is superior after 1448 hours continuous stability reaction, with an average 99.38% conversion rate of CO, an average 90.18% conversion rate of CO2 and an average 99.64% selectivity of CH4, Under the phenomenon has V(H2):V(CO):V(CO2)= 70:22:14 in reaction gases, the catalyst’s performance is superior after 1602 hours continuous stability reaction, with an average 96.05% conversion rate of CO and an average 87.47% selectivity of CH4. That is to say that this catalyst has a very broad prospect in industry.