Simulation Of Methanol Production Process By The Combined Process Of Smr And DMR Based On Natural Gas

Methanol is an important basic material in the chemical industrial production.It is of great significance to do a good job in improving the production efficiency of certain chemical products and increasing economic benefits.At present,most of the methanol is produced by catalytic conversion of syngas?i.e.,the mixture of CO,CO₂,and H₂?which produced by steam methane reforming?SMR?based on natural gas?NG?.However,the ratio of hydrogen to carbon in the synthesis gas produced by this method is high.When methanol is produced using the synthesis gas with a high ratio of hydrogen to carbon,the utilization rate of hydrogen is very low and the excess hydrogen is equivalent to inert gas and needs to be discharged.The emission of the excess hydrogen carries a large amount of CO and CO₂ at the same time resulting in an increase in operating consumption.Therefore,in order to achieve the energy saving and consumption reduction of methanol production,the optimization of the hydrogen-carbon ratio of methanol fresh synthesis gas is one of the key factors.The most primary method to optimize the hydrogen-carbon ratio is to add carbon dioxide.This paper proposes a new CO₂ utilization process based on natural gas?NG?which combines steam methane reforming and dry methane reforming to produce methanol and the productive process is simulated by Aspen plus software.The new process introduces a new synthesis gas production process,namely dry methane reforming?DMR?which is also known as CO₂ reforming,however,the reaction of DMR is strongly endothermic and the required temperature and the energy consumption is high so that the catalyst is easy to accumulate carbon.Therefore,SMR is combined with DMR,so that CH₄,H₂O and CO₂ are mixed and reforming in the DMR reformer.The presence of steam can reduce the hazard of carbon deposition in dry methane reforming reformer and the ratio of hydrogen to carbon is adjusted to the ideal optimal value to increase the utilization rate of hydrogen.In a word,the new carbon-supplementing process combined SMR and DMR changes the production process of the synthesis gas and makes the produced synthesis gas more suitable for methanol synthesis.This has a practical guiding significance for the improvement and optimization of methanol production.First of all,the process which CO₂ is directly injected into the make-up gas is selected for comprehensive analysis and the software Aspen plus is used to simulate and analyze the overall production process and the deficiencies is identified.And the new methanol production process combined SMR and DMR is developed.Then,the equipment modules and appropriate physical properties required in the whole process of methanol production are selected in the Aspen plus software.The new methanol production process combined SMR and DMR is simulated and analyzed.Finally,the new process combined SMR and DMR and the process which CO₂ is directly injected into the make-up gas are evaluated from three aspects involving technological metrics,economic metrics,and environmental metrics.The results show that the new combined process is better than that of the process which CO₂ is directly injected into the make-up gas.The new process combined SMR and DMR is more in line with the economical and sustainable development of industrial production.The new process combined SMR and DMR can effectively reduce the hydrogen emission in the methanol production process,increase the carbon dioxide conversion rate,the total carbon conversion rate,and the total energy consumption,thereby reducing the consumption of NG and other energy sources for methanol production and carbon dioxide emissions.The economic calculation results are obtained using the Aspen Process Economic Analyzer software,which has a good guiding significance for the economic evaluation of methanol production in actual production.In general,the new process combined SMR and DMR has achieved a high utilization of carbon dioxide while reducing the carbon dioxide emissions in methanol production,and has achieved the energy efficiency and environmental protection of methanol production while improving the economic efficiency of its production.