On the possibility of obtaining a cleaner combustion by adding methanol to fluel oil

Purpose of paper is to analyze the possibility of obtaining a better combustion, at least from the air pollution point of view, by adding methanol to fuel oil in an industrial burner. The use of water as an additive to improve combustion of heavy oil has been known for years also if it decreases the caloric value of the unit mass of fuel. This problem can be at least partially overcomed in the case of the mixture of a heavy fuel which atlight one also if from an industrial point of view the real availability of light fuels as methanol must be carefully considered. The experiments has been performed in an industrial furnace equipped with a burner modified to be able to use at the same time fuel oil and methanol. It has been shown that the best performances are obtained if heavy oil and methanol are mixed in the nozzle; the burner is then equipped with two feeding lines. The maximum mass flow rate of the burner is of the order of 50 kg/h of fuel. The percentage of methanol was ranging from 0 to 25% in weight. The characteristics of exhaust gases of the heavy oil were compared with those of the mixture heavy oil-methanol, with particular regard to HC, CO, NO /SUB x/ and carbon concentration; in the experiments the air fuel ratio was considered as a parameter. It has been shown that the addition of methanol is able to reduce some emissions (in particular carbon in the exhaust) and is also able to influence the flame structure (expecially the flame length). The results obtained adding methanol have been also compared with those obtained by means of the addition of water. In conclusion it can be deduced from the experiments that methanol can be profitably used in addition to a heavy oil, also if a modification of the burner structure is required to obtain good performances of the system.