Experimental investigation of flame stability and the effect of air intake pressure for utilizing sludge palm oil (SPO) in the waste oil burner

Flame stability and combustion parameters are important considerations for high-viscosity biofuel oil burners. Flame stability is influenced by the fuel's preheating temperature, whereas combustion parameters reflect flame temperature and emissions produced during combustion. The present study investigates the feasibility of using sludge palm oil (SPO) in a waste oil burner, with a focus on flame temperature and exhaust emissions, including carbon monoxide (CO), carbon dioxide (CO2), unburned hydrocarbons (CxHy), oxides of nitrogen (NOx), and flue gas temperature. The study is conducted in two phases. The first phase involves determining the optimal preheating temperature for SPO. The second phase focuses on identifying the appropriate air intake pressure. Among the tested preheating temperatures of 80, 90, and 100 °C, the preheating temperature of 100 °C was selected based on smoother fuel flow, absence of clogging, and improved flame stability. The performance and emission tests were carried out on a waste oil burner fueled with diesel and SPO with varying air intake pressures of 0.6, 0.8, and 1 bar. Based on the performance and emission characteristics, the SPO can be an alternative to conventional diesel fuel. The response surface methodology is used to optimize the emission parameters based on the desirability of 0.532. The optimized input variables for fuel calorific value and air intake pressure are 39.730 MJ/kg and 0.725 bar, respectively. The predicted emission values for CO, CO2, NOx, flue gas temperature, and CxHy are 7.458 ppm, 5.565 ppm, 20.853 ppm, 484.968 °C, and 0.251 ppm, respectively.