In order to reduce particulate matter pollution in the air caused by wood and its products used for heating, Oskars Švedovs, a PhD student at Riga Technical University's Environmental Protection and Heat Systems Institute (RTU VASSI), in collaboration with scientists, is developing and patenting an innovative compact particulate matter separator that allows a flue gas cleaning plant developed by RTU scientists several years ago to operate as efficiently as possible, using fewer resources.
«Consumption of fuel wood in Latvia is increasing. Around 30% of consumption is generated by households. When solid fuels are burned, fine ash particles are released into the air, which contain various chemicals and can be harmful to both the environment and human health. However, households are not subject to strict emission limits, which in other sectors encourages the development and wider use of various cleaning technologies. This is why compact flue gas treatment plants have not been widely used in Latvia, » says O.Švedovs.
A special reactor for cleaning flue gases in individual boilers, or a «fog machine», where they are sprayed with tiny mist-like water droplets that bind particulate matter and prevent it from entering the atmosphere, was developed several years ago by RTU VASSI scientists. «When testing the reactor, the water treatment used was a challenge. When solid particles remain in the water, they hamper the performance of the «fog machine» and thus the efficiency of flue gas cleaning, » says the RTU PhD student. He started developing equipment to purify the water used in the fog machine so that it could be reused in the process during his undergraduate studies and continues to do so during his PhD studies. In collaboration with Linards Reinis Rozītis, an expert at the RTU Science and Innovation Centre Design Factory, an experimental water purification device has been developed and perfected, which is able to catch with up to 85% efficiency both the particles that settle at the bottom of the device after contact with water and those that float to the surface. The plant is made using 3D printing and vacuum forming technologies. It consists of suspension inlet and dirty and clean water outlet pipes, a settling chamber, a particulate storage chamber, and several filter elements to capture different sizes of particulates. As part of the further development of the plant, the possibility of replacing the nylon mesh used for filtration, which catches particles down to 100 micrometres, with a more efficient and environmentally friendly element is currently being investigated. Testing of the compact particulate separator will also continue, raising the level of technology maturity, which is essential for the future commercialisation of the innovation.
«The patented invention for the separation and concentration of solid particles from technical wastewater in circulating systems is relevant to the water purification and treatment industry and can be used not only in a fog machine, but also in other similar technological processes,» says O. Švedovs. His current PhD work involves the use of low-grade biomass in the production of heating pellets, testing combustion processes and emissions. He concludes that without purification technologies in boilers, such pellets will be difficult to use, while the purification performance will be improved by the invention.
The inventors of the Latvian patent «Compact particulate separator» are RTU VASSI students and scientists O. Švedovs, Miķelis Dzikēvičs, Vivita Priedniece and Ivars Veidenbergs.
The research is supported by the European Social Fund in the project No 8.2.2.0/20/I/008 «Strengthening of doctoral students and academic staff of Riga Technical University and Banking University in areas of strategic specialisation» of the Specific Support Objective 8.2.2 of the Operational Programme «Growth and Employment» «Strengthening of academic staff of higher education institutions in areas of strategic specialisation».
