METHOD OF SELECTING THE WORKING BODY FOR ORC CYCLES OF FLUE GAS HEAT RECOVERY

Background. The choice of the optimal working fluid for condensing heat exchangers operating based on the organic Rankine cycle on gas-fired power and water boilers with waste gas heat recovery arises due to the growing need for energy-efficient technologies and the need to ensure maximum efficiency of generation systems at minimal costs. This requires studying the properties of various working fluids and their optimal use, taking into account specific operating conditions, and addressing the lack of research for specific equipment conditions. Objective . The purpose of the paper is to justify the choice of the working fluid for the heat recovery system with a condensing heat exchanger and a turbine operating on the organic Rankine cycle based on the E-480-560-140 GM power boiler. Methods . The scientific approach in this study is based on the comparative method. This approach involves comparing different options for organic working fluids through a literature review and modelling their operation for existing conditions. During the literature review, approaches that have already been used in other studies and practices were analyzed. Modelling the operation of working fluids made it possible to assess their efficiency and suitability for a specific system, considering its parameters and limitations. Results. A list of effective organic bodies is presented based on a literature review and the results of technical, economic and mathematical analysis. The algorithm for selecting a working body is based on the obtained research results and takes into account the criteria of energy efficiency, compatibility with system parameters, resistance to corrosion and wear, as well as the availability and cost of working substances. Taking these criteria and research conclusions into account, the following working fluids are suitable for the given system: R717, R245FA, R123, R141B. Conclusions. For the conditions of the given project, ammonia (R717) is the most optimal working medium. This decision can be applied to similar conditions of projects on heat utilization of flue gas products of natural gas combustion using ORC cycles