Self-Ignition of Biomass: Parameters and Scaling

To analyze the possible reasons that could cause organic waste to undergo self-heating and self-ignition, two fermentative wastes and chemical oxidation at low temperatures have been studied. Poultry waste and fecal matter were selected to observe whether these fermentative wastes behave differently from lignocellulosic wastes in the temperature range of 120–170 °C. The study suggests that the oxidation process and vapor sorption are similar to those of lignocellulosic materials, and simulations indicate that long periods, lasting many months or more, are required for self-ignition to occur at low temperatures. The oxidation of fresh grass has been studied over a wide temperature range, from 50 to 165 °C, revealing an increase in the heat evolved at low temperatures compared with what would be expected from the extrapolation of data obtained at high temperatures. Simulations suggest that self-ignition can occur after a relatively short period of time of approximately 1–4 days at low temperatures.