EXPERIMENTAL STUDY ON THE COMBUSTION AND NOx EMISSION CHARACTERISTICS OF DME/LPG BLENDED FUEL USING COUNTERFLOW BURNER

摘要

Dimethyl ether (DME) continues to be considered as an alternative fuel to conventional hydrocarbon fuels. Specifically, DME has been considered as a substitute fuel for liquefied petroleum gas (LPG) because the physical and chemical characteristics of DME are similar to those of LPG. However, the combustion performance for DME has not yet been established. In this study, the combustion and NOx-emission characteristics of LPG, DME, and an LPGIDME-hlended fuel were experimentally investigated in a counterflow nonpre-mixed flame. The flume structure, flame temperature, NOx concentration, and distribution of OH radicals are reported. In this experimental study, the types of LPG used were butane 100%, butane 80% + propane 20%, and butane 75% + propane 25"A< by mass with DME mole fraction varied from 0 to 100 mole%. The experimental results indicated that the combustion and NOx emission characteristics of LPG fuels varied with the DME mole fraction. As the DME mole fraction increased, the flame thickness increased, but the flame length decreased. Also, the flame became wider, and its origin moved closer to the oxidizer nozzle with increasing DME mole fraction. In addition, as the DME mole fraction increased, the maximum flame temperature increased due to fast pyrolysis of DME as a result of the high oxygen content (～35% by mass) in DME. Moreover, NOx concentration decreased with increasing DME mole fraction in all LPGs.