2015 年 50 巻 1 号 p. 119-124
A study was conducted to improve diesel generator efficiency using waste plastic decomposition oil (WPDO). Waste plastic reaches an annual figure of 10 million tons or more in Japan. Although it is thought that material recycling is the best approach to preserve the environment, its energy yield based on life cycle is not sufficient. Therefore, waste incineration to produce electricity with thermal power generation is recommended. However, this thermal recycle needs a huge facility, and requires extra energy to transport waste plastic. Consequently, another method of thermal recycle using WPDO is considered. The WPDO is used to run a diesel engine to increase generator efficiency. However, WPDO emits much nitrogen oxide (NOx) and smoke (exhaust gas light absorption coefficient). In this paper, the use of water emulsion WPDO to reduce NOx and smoke is proposed. An experimental study with water concentration ratios of water emulsion WPDO of 10%, 20%, and 30% respectively, was conducted. The fuel properties such as density and kinematic viscosity were measured. Finally, each water emulsion WPDO was burned in a conventional 219-cc diesel engine. Although total hydro carbon (THC) and carbon monoxide (CO) increased, NOx and smoke reduced drastically. The amount of NOx and smoke emissions were reduced by 60% at the maximum load compared with gas oil. Moreover, brake fuel specific consumption (BSFC) slightly improved at 10% and 20% water concentration ratios.