Spray atomization characteristics of biomass pyrolysis tar: Influence of methanol addition, temperature, and atomization pressure

Pyrolysis tar, the main by-product of low-temperature biomass pyrolysis, can potentially replace fossil fuels and help achieve carbon neutrality. The efficient atomization of pyrolysis tar is a prerequisite for clean combustion. In this study, an experimental platform was built to explore the influence of methanol addition, temperature, and atomization pressure on the spray atomization of pyrolysis tar. The results indicated that methanol addition was more effective at improving the pyrolysis tar fluidity than heating at temperatures lower than 40 °C. There was no significant change in the composition of pyrolysis tar after adding methanol. The atomization results showed that the optimal experimental parameters were 12 wt% methanol, 80 °C, and an air pressure of 0.6 MPa. The addition of methanol had little effect on the spray angle, which was mainly affected by the atomization pressure. The r value was used to measure the degree of the effect of process parameters, and the degree of the effect increased with the r value. For the spray droplet size, the r values of methanol addition, temperature, and air pressure were 57.3, 9.1, and 8.8. In contrast, for the spray angle, the r values were 3.6, 2.4, and 9.8, respectively.