抄録
Objective. In this paper, we focused on Bio-DME (Biomass Di-methyl Ether) in BTL (Biomass-to-Liquid) fuel liquefaction system through a gasification process. Based on the bottom-up methodology, the inventories of CO2 emissions and energy intensities were estimated. In the system boundary, the sub-systems of the pre-processing, the energy conversion, and the fuel transportation were included. Considering the scale and the operational conditions (an inner pressure and a reaction temperature) of BTL plant, the inventories were estimated. Also, the uncertainties in the pre-processing, that is, the moisture content of biomass materials and the transportation distance to the plant were simulated by the Monte Carlo simulation. In the pre-processing, there were three processes of chipping, transportation and dryer. In the energy conversion, we executed the process design on the following two types; the medium scale of BTL plant through pressurized fluidized bed gasification and the small one through BLUE Tower (BT) process were assumed. Both plants have a liquefaction process. Also, due to the process design, the auxiliary power of each plant was considered. In addition, the liquefied fuel (Bio-DME) was assumed to be delivered using a 10 kL tank lorry.
Results and Discussion. As the results, in the small scale plat (BT process), CO2 emissions of 45.8-60.5 g-CO2 /MJ and energy intensities of 1.44-1.63 MJ/MJ were obtained. Conversely, In the medium one, CO2 emissions of 22.5-51.6 g-CO2/MJ and energy intensities of 0.29-0.66 MJ/MJ were obtained.
Conclusions. From the viewpoint of the environmental statement, Bio-DME was likely to be superior to DME of natural gas origin.
