Известия Томского политехнического университета: Инжиниринг георесурсов (May 2022)
CALCULATION OF THE PARAMETERS OF THE SCHEME OF A GAS-STEAM PLANT WITH DEEP UTILIZATION AND HEAT RELEASE
Abstract
The relevance of the work is conditioned by the improvement of thermal schemes and optimization of the parameters of gas-steam installations in order to reduce the consumption of such energy resource as natural gas in the production of electricity and the release of heat. The proposals for improving the schemes of gas-steam plants supported by calculations, will increase their fuel heat utilization factor and reduce the amount of environmentally harmful emissions into the environment. Purpose: development of a method for calculating the thermal schemes of gas-steam installations in order to improve their scheme based on a versatile parametric analysis and selection of optimal parameters and operating modes. Objects: gas-steam plants with the release of electricity and heat based on gas turbines with steam injection into the combustion chamber, and deep utilization of heat and moisture from combustion products. Methods: numerical research methods based on material and energy balances of systems and elements of gas-steam installations. Results. The authors developed the method for calculating the thermal scheme of a gas-steam plant with the release of electricity and heat, and deep utilization of heat and moisture from combustion products. It was determined that heat and moisture introduction into the heat exchanger circuit makes it possible to lower the temperature of the combustion products leaving the heat exchanger to 15...45 °С, and also to capture up to 90...120 % of moisture from them. To reduce the temperature of the cooling water at the inlet to the heat and moisture exchanger, a heat pump was introduced into the circuit, which also makes it possible to increase the temperature of the network water in the heat supply system. The new scheme, due to a significant reduction in heat loss with exhaust gases, makes it possible to increase the fuel heat utilization factor by 45…100 % compared to the scheme without heat release when calculating the net calorific value of the fuel. It was found that the use of this scheme is most beneficial when the compression ratio in the compressor is from 20 to 80 and the temperature at the outlet of the combustion chamber is 1400 ... 1700 °С, while the net heat utilization factor of the fuel will be 102 ... 107 %; net efficiency 50…58 %; steam injection consumption 5,5…8,5 kg/kg of fuel; excess of captured condensate 0,2…1,2 kg/kg of fuel; specific heat load of heat consumer 23…28 MJ/kg of fuel.
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