The photo is sourced from tpu.ru
Wood biomass consists of fragments of various shapes and sizes, which are produced during wood-cutting and woodworking. The TPU scientists’ biomass material of choice was cedar, which is not only the most widespread tree crop in Siberia but also a material with a high calorific value and a high content of volatile matter – these qualities make the ignition process easier. In the course of their experiment, the researchers used equal-size particles of three different configurations: a rectangular parallelepiped, a cube and a plate. The particles were put into a combustion chamber, the conditions in which were similar to those in the furnace units of boiler thermal power plants. The heating and ignition processes were recorded by a high-speed camera, and the resulting footage was analysed by the scientists.
“During the experiment, curious dependencies were discovered. In case of increase in the typical size of rectangular parallelepiped-shaped wood biomass particles, the delay periods of ignition initially start getting longer (which is an obvious consequence), but when a certain threshold value of the typical particle size is crossed at a later point, these delays start getting shorter,” project manager Semen Syrodoy, doctor of technical sciences, is quoted as saying by TPU. “These results are unusual from the viewpoint of the classical theory of ignition processes in condensed media, and they had never been obtained before. We will have to find out what causes this phenomenon.”
The researchers also discovered that an increase in the size of cube-shaped wood particles does not affect the burning dynamics. Meanwhile, plate-shaped particles with the same mass tend to combust quicker than those in the shape of a cube or a rectangular parallelepiped.
The results of the study will help increase the operating efficiency of biomass facilities, which have the advantage of power supply reliability. While the utilisation rate of solar panels and wind generators in the United States over the first ten months of 2022 stood at 27% and 36% respectively, the utilisation rate of waste wood-based facilities reached 59%. The utilisation rate of such facilities depends not on the weather but on the availability of fuel and the dynamics of final energy demand. This is why waste wood-based power generation is almost as reliable as power generation from fuel oil, gas and coal.