Modeling And Analysis Of Syngas For LNG And Methanol Co-production Process:Based On Lurgi Gasification

With the rapid development of China's coal chemical industry,the Coal to Synthesis Natural Gas?CTSNG?projects have been rapidly launched all over the country in recent years.However,poor operation economy and sustainability of the large-scale CTSNG project become thorny problems.Therefore,it is necessary to think about the process innovation and optimize to promote the sustainability of these projects.A coal-based coproduction process of Coal to Liquefied Natural Gas?LNG?and methanol?CTLNG-M?process is developed and key units are simulated in this study.The goal is to find improvements of the low-earning CTSNG process using the same raw material but producing a low-margin,single synthesis natural gas product.The CTLNG-M process co-generate high value-added products of LNG and methanol,in which CH₄ is separated from the syngas through a cryogenic separation unit,while the remaining lean-methane syngas is then used for methanol synthesis.The simulation results show that the CTLNG-M process is designed with the output products of 642,000 tons/a LNG and 1,367,800 tons/a methanol,which leads to a carbon utilization efficiency of 39.6%and reduction of CO₂ emission by 130,000 tons/a.In addition,a higher energy efficiency of 53.1%and internal rate of return?IRR?by 6%are also achieved,contrasting to the CTSNG process.Though the energy consumption of the new process is increased by 9.3%,after detailed analysis of energy network,The simulation results show that:?1?decrease the feed temperature of syngas;and?2?increase the refrigerant's feed pressure can both effectively reduce the energy consumption by 30,446 k W in the cryogenic separation process,which is 27.6%lower than that of the original simulation process.Therefore,in view of the existing problems of CTSNG project,the CTLNG-M route provides a more flexible production scheme,with optimization objectives of energy efficiency and element utilization.This co-production process is set to realize the rational utilization of resources and generate social value.