TECHNO-ECONOMIC AND ENVIRONMENTAL ASSESSMENT FOR A POLYGENERATION AND LOW EMISSION BIO-DME PRODUCTION FROM RICE STRAW IN VIETNAM

The conversion of rice straw into energy such as dimethyl ether (DME) plays a significant role in driving and improving energy conversion efficiency due to its abundance and eco-friendliness”. Not only is an alternative for fossil fuels, rice straw-derived DME also affects the agriculture-based value chains. In this study, an upgrading DME production process was developed by HYSYS simulation for lower carbon dioxide (CO2) emission and then figured out its feasibility through techno-economic and environmental analysis. Technically, the modelled process generates around 2.3 ton/h of DME with a purity of 99.96% and an energy conversion efficiency (ηDME) of 75%. Otherwise, the additional presence of an off-gas absorber and CHP plant in the process reduced 84% of GHG emissions compared to the conventional process (0.21 kg CO2-eq/kg DME compared to 1.36 kg CO2-eq/kg DME, specifically). The CO2 capture also creates more products for this process and increases carbon efficiency to 94.6% with no CO content in fuel gas leaving the CHP section. The unit production cost (UPC) is estimated at 1,143 USD per ton of DME. These results created a net new positive contribution to commercial DME production, directing the majority of economic activity toward green and sustainable technology.