Decision working medium for lower cycle CCGT trinary type

Abstract

Abstract. The object of the study are low-boiling substances, which can be used as working fluid in the Organic Rankine cycle (ORC) combine cycle gas turbine (CCGT) trinary type. Purpose of research is search for substances with the best thermodynamic, thermophysical and ecological properties. The calculation algorithm represents a mathematical calculation of CCGT in which the lower cycle, operating on low-boiling fluid and utilizes low-potential heat, as an air-cooling device On the basis of available scientific and practical facts on the use of working fluids the organic Rankine cycle for analysis were selected ozone-safe refrigerant: butane, pentane, R236ea, R236fa, R123, R245ca, R245fа, R365mfc, RC318. For these substances were found and tabulated critical pressure and temperature, condensation pressure, density and dynamic viscosity at a given condensation temperature. Studies have shown that the highest thermal net efficiency is achieved when using natural Freon pentane and synthetic R365mfc. Net efficiency CCGT strongly depends on the condensation temperature of the substance. For example, when using pentane when the condensation temperature decreases on 10 С net efficiency increases about 0.71 %.

Thermoeconomic analysis and multiobjective optimization of a combined gas turbine, steam, and organic Rankine cycle

“…Thermodynamic parameters of the inlet flue gas to the HRSG are known from the previous section. By applying the following equations, the total mass flow rate of the produced steam could be calculated: 11 express the amount of enthalpy through stages 8 to 11.…”

“…Tsibulskiy et al investigated the potential of low boiling fluids to be employed as a working fluid in the organic Rankine cycle (ORC) combined cycle gas turbine. The study was designed to find the best fluid regarding thermodynamic performance, thermophysical, and ecological properties.…”

Algorithm for calculation of a CCGT of a trinary type with an air condenser

“…The working body of the steam turbine unit (STU) of this CCGT is water. The ways of further increasing the efficiency of the combined-cycle plant are given in the paper [1]. This is an increase in the initial temperature of a gas turbine, a decrease in heat losses in a steam turbine cycle and a heat recovery steam generator (HRSG), lower temperature heat rejection from the cycle.…”

“…At a given steam temperature before the turbine, the increase in the efficiency of the STU is possible only due to the decrease in the heat removal temperature in the cycle, therefore it is proposed in [3] to use a low-boiling substance as the working fluid of the cycle of the STU, and to remove heat from it in an air condenser. This in winter will allow to reliably remove heat in the cycle at negative temperatures and increase the efficiency of the STU and CCGT.…”