MODELING AND SIMULATION OF DIMETHYL ETHER SYNTHESIS FROM SYNGAS

Abstract

With ever increasing concerns on environmental pollution, dependency on conventional fuel resources, future oil supplies, and energy security, the global community is trying to find some non-petroleum based alternative fuels, along with more advanced technologies such as fuel cells to put the energy to a greater use, the most momentous being the one that has the greatest impact on society, environmentally and economically, with the major impact areas being non-petroleum feed stocks, fuel versatilities, infrastructure, well to wheel greenhouse gas emissions, well to wheel efficiencies, availability, economics and safety. The driving force for developing alternative fuels is no longer solely to reduce oil dependence on select oil exporting companies. Noxious exhaust emissions generated by combustion of fossil fuels as well as increased levels of carbon dioxide. a major contributor towards global warming, have necessitated the need to develop alternative fuels that address clean-burning as an important criteria. Dither methyl ether has been identified as a multi-source and a multi-purpose fuel that can effectively assuage the aforesaid concerns by establishing stable indigenous fuel supply and alleviating environmental concerns. Dirnethyl ether can be readily manufactured from natural gas reforming and gasification coal, renewable resources such as wood and biomass, as well as waste matter. Among the - various processes for chemical conversion of natural gas, direct synthesis of dimethyl ether is most efficient. It can be used as a clean burning fuel in diesel engines , as a household fuel aRer blending it with liquefied petroleum gas ( blends up to 20% DME requires no modification to equipment and distribution networks. It is also used in power generation by gas turbines, in fuel cells, as a fcedstock for producing chemicals and oxygenates and as a coolant and also as a propellant in aerosol market. In the present work, a one dimensional steady state mathematical model for a pipe shell fixed bed reactor has been developed under isothermal conditions. The mathematical model comprises of six ordinary differential equation for the six components participating in the reaction for synthesis of dimethyl ether along with the reaction kinetics. These model equations have been solved by using ode solver tool ode45 in MATLAB 2013 and has been simulated for best reactor conditions of pressure, temperature and molar feed ratio. In view of the simulation results, it has been concluded that the pipe shell fixed bed reactor best operates at a temperature of 533 K, at a pressure of 50 bars and molar feed ratio of 3.5.