Energy saving during the partial heat load period by integrating a steam-heated absorption heat pump into the thermal scheme of a PT-60/70-130/13 steam turbine

Abstract

The task of determining the efficiency of operation of an absorption heat pump (AHP) with steam heating (COP conversion factor = 1.71) integrated into the thermal circuit of a PT-60/70-130/13 steam turbine that releases production steam and hot water during the partial heat load period (spring and autumn; also referred to as the inteheating period) is being solved in this paper. Variants of operation of the PT-60/70-130/13 with an integrated AHP with a capacity of ~17.25 MW in the partial heat load period were studied when steam with parameters of 1.296 MPa, 280°C was realised in the production selection of the adjustable turbine at flow rates of 20, 30, and 50 t/h with a variable heat load on hot water supply, which was determined by the return network water consumption task 1000–1400 t/h, while the ‘useful’ electrical power of the power complex was provided at ~30 MW. At electricity prices of 0.13 USD/(kWh) and standard fuel of 309 USD/t for Ukraine, the simple payback period of 17.25 MW AHP as part of the PT-60/70-130/13 steam turbine for the partial heat load period at a production load of 20–50 t/h of steam at the consumption of return network water of heat supply 1000–1200 t/h can decrease to two years. At the same time, during the partial heat load period, which lasts ~4404 hours in Ukraine, up to ~1.2% of fuel, up to 44% of technical water for feeding the circulation cooling system, and 0.4% of softened water for feeding are saved. A tangible environmental effect is achieved due to the reduction of harmful emissions – actual heat and hazardous gases – to the atmosphere: CO2 by 1118.7 tons, NOx by 5.87 t, thus saving ~41,000 of technical water.