Authored by Chen Wei (David) Zheng:
Summerhill Biomass Systems uses and consults on green and sustainable biofuel processing – including wood powders. We evaluate our clients’ materials for acceptability as a powder form of biofuel. In addition to planning and selecting the optimum “powdering” methods, we look at sizing and combust-ability of materials using a Summerhill burner.
The above table(Click it to enlarge) shows the results of a test result on a sample set of powder variables recently used on a Summerhill Biomass System. Two bags of wood powder were used from the same source. One bag has been opened for two years, while the other one is fresh (unopened). The green, red and black lines represent different variables tested with the first bag. Red was toasted for 2 hours. Black was toasted for 1 hour. Green was tested in an as-is state, after separating out the larger particles that had congealed over time. The grey line represents the fresh bag of wood powders, which was unopened, but had been stored in a barn for two years. The lines all demonstrates the distribution of particle size across each of the samples.
Combustible particles are larger than 100 micrometres. Hence, the yellow area on the table shows the burnable range. The first picture in the left hand side of the table strongly correlates to a powder particle sizes between 50 to 80 micrometres won’t burn even with a robust fire source such as a propane torch. Furthermore, compared to the open bag powders, flame of the fresh powder is less distorted, which manifests a far more thorough combustion. Summerhill Biomass Systems Inc. has performed initial emmision tests confirming no presence of volatile organic compounds(VOC). These results demonstrated that the carbon monoxide levels were 1/5 those produced with a new pellet furnace. Thus, a bright, clean and ordourless flame is a result of complete combustion.
According to the test results, biofuels in powder form are a perfect candidate for a sustainable energy resource, especially when sized larger than 100 micrometres.