Experimental Research On Carbon Dioxide Reforming Of Methane To Synthesis Gas Of Catalyst

With the continuous development of the world economy, the reforming of methane withcarbon dioxide to produce synthesis gas is concerned by scholars. The reaction has thefollowing advantages:(1) CH4-CO2reforming can get synthesis gas with a low H2:CO ratio(≦1), which can be used for the production of carbonyl and F-T synthesis;(2) the reformingof methane with carbon dioxide is a reversible reaction with large reaction heat, which can beused as the media of storing and transmitting energy;(3) it has made full use of methane andcarbon dioxide, which makes great contribution to reducing the emissions of greenhousegases and protects the environment. Ni catalysts are widely applied in the reforming ofmethane with carbon dioxide to produce synthesis gas, due to their low cost and abundantresources. Since it is a strong endothermic reaction and at high temperatures, Nickel-basedcatalysts will deactivate because of carbon deposition. It is found that, Ni-based catalysts’performance can be enhanced by choosing proper supporters, adding promoters to thecatalysts, controlling the loading of active component and improving the reaction equipment.This experiment adopted different methods to prepare three types of catalysts, ieNi/γ-Al2O3, Ni-MgO/γ-Al2O3and barium modified Ni/γ-Al2O3catalysts. Using the fixed bedreactor of the reforming of methane with carbon dioxide, this article researched the effects ofnickel content in the catalysts and additives content of MgO of the reforming reaction,investigated the activity and stability of the catalysts, and researched temperature,, feed gascomposition and feed speed on the conversion rate of methane and carbon dioxide, and on theselectivity of carbon monoxide and hydrogen. Finally, the optimum technological conditionwas determined.The experimental results show that, barium modified Ni/γ-Al2O3catalyst, which isprepared by the coprecipitation method, has good catalytic activity and stability. What’s more,it has higher activity than Ni-MgO/γ-Al2O3catalysts and Ni/γ-Al2O3catalyst. The influence of Ni content on catalytic activity of the reforming of methane with carbondioxide: barium modified Ni/γ-Al2O3catalyst has the largest catalytic activity in thereforming of methane with carbon dioxide and no carbon deposition. When the Ni content is8%, Ni/γ-Al2O3, Ni-MgO/γ-Al2O3, barium modified Ni/γ-Al2O3catalyst have good catalyticactivity, methane and carbon dioxide have high conversion rate; Selectivity of carbonmonoxide with hydrogen increases to a certain value and keeps stable with the increasing ofnickel content, Increases.The influence of reaction temperature on catalytic activity of the reforming of methanewith carbon dioxide: with the increase of reaction temperature, the conversion rate of methaneand carbon dioxide, the selectivity of carbon monoxide and hydrogen both increases enlargesmarkedly, larger value is achieved at700℃. Continue raising the temperature, Ni/γ-Al2O3catalyst begins to appear carbon deposition gradually. The conversion of feed gas and theselectivity of synthesis gas begin to decline.In the experiment of the catalyst activity and stability of Ni/γ-Al2O3, Ni-MgO/γ-Al2O3,Ba modified Ni/γ-Al2O3catalysts: barium modified Ni/γ-Al2O3catalyst can be remained thestate of stable activity in two hours to fifteen hours. Ni-MgO/γ-Al2O3catalyst and Ni/γ-Al2O3catalyst have poor stability. With the increase of reaction time, the catalyst becomes unstablebecause of the high temperature.The influence of composition of feed gas on catalytic activity: It tends to positivedirection reaction when increasing the concentration of the reactants. The conversion rate ofmethane becomes higher as the increasing of feed gas. The conversion rate of carbon dioxidegradually reduces due to its increasing content. And the selectivity of carbon monoxide andhydrogen increases with the increasing of feed gas composition proportion.The influence of feed space velocity on catalytic activity: In the reforming of methanewith carbon dioxide, the conversion rate of carbon dioxide and the selectivity of carbonmonoxide with hydrogen gradually reduce with the enlargement of feed space velocity underthe catalyst of Ni/γ-Al2O3carbon dioxide, Ni-MgO/γ-Al2O3carbon dioxide, barium modifiedNi/γ-Al2O3. The influence of additive content of MgO on catalytic activity: Ni-5%MgO/γ-Al2O3catalyst has high catalytic activity and stability, the conversion rate of carbon dioxide and theselectivity of carbon monoxide with hydrogen gradually increase with the rising oftemperature.