Power increase of the power plant with single-circuit ORC plant with a wet medium, supplied with water in appropriate proportions from the Lower and Middle Triassic Reservoirs

Abstract

This article presents an analysis of the efficiency of the ORC power plant with a wet circulating medium. The power plant is supplied from two heat sources, which are geothermal water streams obtained from the Lower Triassic and Middle Triassic Reservoirs. In the ORC system, it was assumed that one of these streams is directed to the superheater and the other to the evaporator. In the work, two variants of ORC power supply were considered. The first one, in which the maximum stream of water from the Middle Triassic Reservoir ṁg2 = 55 kg/s at a temperature of ${\rm{T}}_{{\rm{g1}}}^2$ = 104°C powers the evaporator, while the water stream from the Lower Triassic Reservoir ṁg1 = 25 kg/s at a temperature of ${\rm{T}}_{{\rm{g1}}}^1$$ = 128°C powers the superheater. In the second variant, the maximum water stream from the Lower Triassic Reservoir ṁg1 = 25 kg/s and a temperature of ${\rm{T}}_{{\rm{g1}}}^1$$ = 128°C feeds the evaporator, while the water stream from the Middle Triassic Reservoir ṁg2 at a temperature of ${\rm{T}}_{{\rm{g1}}}^2$ = 104°C supplies the superheater. In both variants, the geothermal water stream directed to the superheater is the size resulting from ORC plant operation and cannot exceed the maximum flow value for a given geothermal reservoir. The following working substances were taken into account in the analysis: cyclopropane, R143a, R32, propylene, R22, propane, R134a. The analysis carried out showed that in the ORC power plant with a two-source supply the maximum system power was obtained in the case of the first variant for the working medium R143a.