Thermodynamic analysis of fuel composition and effects of different dimethyl ether processing technologies on cell efficiency

Abstract

Solid oxide fuel cell (SOFC) is one of the most attractive energy conversion systems, while dimethyl ether (DME) is an alternative clean fuel, and thus the application of DME in SOFC has great attraction. Fuel compositions are mainly determined by fuel processing technologies, which can affect the cell efficiency. In this paper, the relationships among fuel composition, oxygen to carbon (O/C) ratio, carbon deposition and cell efficiency are investigated for different DME processing technologies. According to the calculated results, SOFC with steam reforming of DME has the highest efficiency at the same O/C ratio and equivalent fuel utilization, while for catalytic partial oxidation of DME, the cell efficiency decreases rapidly with the increase of O/C ratio. The efficiency of SOFC with CO2 reforming of DME decreases with the increase of O/C ratio, especially at high O/C ratio and low equivalent fuel utilization. When the O/C ratio is 1.5, solid carbon can't be formed, where the cell efficiencies are 51.7% for steam reforming of DME, 42.2% for DME reforming with H2O and O2, 32.7% for catalytic partial oxidation of DME, 49.3% for DME reforming with anode off-gas and 41.4% for CO2 reforming of DME at 80% equivalent fuel utilization.