Utilization of palm acid oil for a diffusion combustion burner as fuel and nitrogen oxides reduction by the thermally decomposed hydrocarbons

Palm acid oil (PAO) is considered to be a possible renewable energy. PAO-diesel mixed fuel can keep PAO deposition temperature low, which makes it easy to use as the burner fuel at low risk. However, the use of PAO for combustion fuel and its emission characteristics have not been reported. This study is focused on utilizing PAO as a burner combustion fuel and on finding its emission characteristics including the cause of NO reduction in the burner by PAO. The mixed fuels are prepared and PAO precipitations in the mixed fuel are evaluated. After that, the burner tests were performed. Finally, the cause of the NO reduction in the burner is investigated with a flow reactor. The results show that chemical regents and ultrasound make PAO particle smaller and control a part of PAO deposition. In the burner, 20wt.% PAO having relatively low free fatty acid (LFFA) fuels reduce NOx by up to 30% while keeping high temperature. In the reactor, NO is reduced not only 60% by diesel but also 75∼80% by the PAO (LFFA) at equivalence ratio (φ) =2.63. This study demonstrates that the PAO has potential for NO reduction though complete PAO deposition control is difficult. [Display omitted] •Utilization of palm acid oil as combustion fuel in a diffusion combustion burner.•Deposit evaluation at a low temperature for palm acid oil -diesel mixed fuel.•Chemical regents and ultrasonic irradiation control palm acid oil deposition.•Free fatty acid in palm acid oil affects NOx reduction in the diffusion combustion burner.•Thermally decomposed hydrocarbons reduce NO in fuel rich condition with oxygen.