Researchers of Tomsk Polytechnic University have developed an alternative fuel for small energy. They proposed to use sawdust as an environmentally actual agent for producing mixed coal pellets. Such fuel is cheaper and more environmentally friendly than its alternatives. The research was conducted with the support of the Russian Foundation for Basic Research.
Photo: fuel samples
The technology proposed by the researchers of the TPU Ecoenergy 4.0 Research Center does not require overseas equipment and is an environmentally efficient solution for waste recycling of the timber industry.
“During the coal combustion, anthropogenic gases, such as sulfur oxide, nitrogen and carbon dioxide emit essentially into the atmosphere. We have carried out a lot of experimental research and proved that due to physicochemical interactions during the joint thermal decomposition of coal and wood waste, emissions of sulfur oxide (up to 90%) essentially and non-additively reduce depending on the sulfur concentration in the mixture.
Sulphur oxide binding occurs more intensive in the range from 600°С to 800°С. In the process of the wood thermal decomposition, moisture contained in the wood is released in the form of a vapour-gas mixture. The sulfuric acid vapour released in the coal thermal decomposition reacts to the vapour of moisture and metal oxides contained in the solid part of coals and wood, and under the high temperatures forms aluminium and calcium sulfates. Sulfur bound in sulfates settles in the ash residue and does not release in the form of oxides into the atmosphere,” tells Stanislav Yankovsky, associate professor of the TPU Butakov Research Center and head of the project.
The researchers found conducting the experience that the optimum concentration of the wood component in the fuel is 25%. Besides, the sulfur emissions reduce by 60%, meanwhile, the value of such mixed fuel reduces by less than 6%.
The production of the mixed fuel pellets based on coals of various ranks and wood waste allows providing Russian regions with affordable fuel where is no local coal mining, however, at the same time, there is continuous harvesting and huge deposits of wood waste.