Yakymovych M. Development and study of carbonaceous raw materials conversion process using plasma technologies

The potential indicators of conversion processes efficiency of hazardous waste as a renewable carbonaceous raw material using plasma-steam technologies are determined in dissertation work. The task of optimizing them was presented on the example of gasification of sewage sludge of wastewater treatment plants in terms of further commercialization of such technologies. In order to successfully commercialize these technologies, it is important to achieve their high energy efficiency – so that the energy resource resulting from the gasification is enough not only for the power self-sufficiency of the gasifier, but also for the production of additional power to external consumers. So this thesis, focused to resolve, ultimately, this problem. Experimental studies were carried out at the equipment for gasification of renewable carbonaceous raw materials on the basis of a serial low-power plasma torch "Multiplaz-3500". It was created at the Institute of Coal Energy Technologies of the National Academy of Sciences of Ukraine together with the Institute of Gas of the National Academy of Sciences of Ukraine. The processes of various types of solid organic fuels and waste like brown coal, fast growing algae, wood chips, water-sludge mixture and sewage sludge of wastewater treatment plants, as well as the conversion of bioethanol into synthesis gas were investigated. It is shown that all of them in the conditions of this process are the source of hydrogen-enriched synthesis gas. The process of plasma conversion of 60% ethanol solution is studied. It is shown that the fuel consumption for hydrogen production at the conversion of ethanol is 16.50 UAH / liter, at the cost of hydrogen 37.5 UAH / liter. The quantitative estimation of the energy efficiency of the process of plasma-steam conversion of the sewage sludge of wastewater treatment plants are obtained as a result of thermodynamic calculations. It shows that the technologies based on it can operate in a mode close to energy self-sufficiency. It is determined that an additional significant increase in the energy efficiency of conversion is achieved with the partial excessive introduction into the number of oxygen reagents. This allows to produce additional electricity as a result of processing sewage sludge of wastewater treatment plants, even taking into account the additional consumption of electricity on the vitrification of mineral part of the sewage sludge, containing heavy metals in its composition. In the economic realities of the national economy, this will promote the commercialization of this kind of technology. Taking into account the specified indicators of gasification of this process, a competitive project «The development of steam-plasma technology of aeration stations sewage sludge conversion» was prepared with the support of Ministry of Education and Science of Ukraine. It has the status of a state order in accordance with the Resolution of the Cabinet of Ministers of Ukraine of July 27, 2016, No.476 «On State order for scientific and technical (experimental) development and scientific and technical products in 2016». Currently, this project is being actively implemented by the Institute of Gas of the National Academy of Sciences of Ukraine.