In order to utilize palm acid oil (PAO) for combustion fuel, improvement on the low temperature fluidity of PAO-diesel mixed fuel is demonstrated using polyglycerol fatty acid ester (PFAE). PFAE has an effect on reducing the PAO deposition at low temperature definitely in exchange of viscosity increase. One of the PFAEs: THL-17 puts the aggregation of PAO particles off in the beginning of the cooling in addition to keeping the uniform distribution of the PAO particles. Combustion experiment using an industrial diffusion burner fueled by the PAO-diesel mixed fuel with PFAE is carried out to evaluate the combustion and emissions characteristics. The result shows that the furnace outlet temperature of THL-17:2wt.% mixed fuel almost keeps as high as the temperature of diesel fuel. On the other hand, the THL-17:2wt.% mixed fuel decreases NOx by maximum 30 % in comparison with the diesel fuel, showing a possibility that NOx is reduced by PAO.

To effectively utilize palm acid oil (PAO), PAO mixed fuel usability was studied by 1. analyzing PAO properties, 2. making PAO-diesel and PAO-fuel oil A mixed fuels using solvent and ultrasonic homogenizer, 3. evaluating stability of PAO-diesel mixed fuel in cool temperature, 4. conducting an experiment in combustion of PAO mixed fuel using diffusion burner, 5. carrying out an experiment in NO reduction caused by thermally decomposed PAO mixed fuel using a plug flow reactor. Main components of PAO used in this study are considered to be palmitic acid and oleic acid. The PAO includes about 80% free fatty acid and a little bit water. Total calorific value of the PAO is less than diesel fuel and fuel oil A. To stabilize PAO-diesel and PAO-fuel oil A in cool temperature, an ultrasonic homogenizing with pulse generation is used and the remarkable effect is presented but prevention of both coagulation and deposition is difficult when the temperature is below about 10°C and PAO is contained over 20%. Diffusion combustion burner using the PAO mixed fuel demonstrates that NOx is reduced within the specific range:1.2~1.6 of air excess ratio in spite of the combustion chamber outlet temperature are high as compare with the temperature of diesel fuel. The cause of NOx reduction was studied by the plug flow reactor that showed both diesel fuel and PAO-diesel fuel are able to reduce NOx, especially at about φ=3.0, NOx is reduced by 55% which suggests a potential of NOx reduction caused by thermally decomposed hydrocarbons.