Thermodynamic Efficiency of PGU-110 Steam and Gas Plant

Abstract

The necessity and expediency of use of steam and gas plants in Russia are discussed. The flow diagram of the thermal plant PGU-110, equipment composition, power and heat generating data, etc., are given. The energy efficiencies of the plant under summer and winter operation conditions are calculated. Commercial power generation is developing along the path of building high-efficiency power plants using steam and gas technologies [1‐3]. Steam and gas thermal power plants (SGP) ensure power generating efficiency of 50‐60%. In 2011, the energy-generating block of the PGU-110 plant (Fig. 1) was updated for electric power and heat generation under basic operation conditions. The installed power-generating capacity of PGU-110 was 110 MW and heat-generating capacity was 66 Gcal/h, and its efficiency was 50%. Updating of the SGP made it possible to increase power generation, reduce specific fuel consumption, and substantially curtail emissions of noxious substances to the atmosphere. Composition of Basic Equipment of PGU-110 Plant. The gas-turbine plants (GTP) were of General Electric (GE) LM 6000 type (two units) with BRUSH-made BDAX7-290ERJT-type generators (two units). The LM 6000 plant had a twoshaft gas-turbine engine consisting of a 5-stage LPC, 14-stage HPC, an annular combustion chamber, a 2-stage HPT, a 5-stage LPT, a block of distributing regulator, and auxiliary equipment. The rated capacity of the GTP was 44.65 MW (at 101.3 kPa atmospheric pressure, 288 K air temperature, and 60% relative humidity). The fuel was natural gas injected at 4.65 ± 0.14 MPa pressure. The parameters of the LM 6000 GTP under various operation conditions are listed in Table 1. The boilers were of the KGT-44/4.6-435-13/0.5-210 type (two units) built by Energomash (Belgorod, Russia) for generation of superheated steam by utilizing the heat of flue gases of the GTP. To enhance the heat utilization efficiency, gas-steam water heaters were installed past the boilers. For operation of the block in the condensation mode, the parameters were as follows: high-pressure steam ‐ pressure p O HP = 4.6 MPa; temperature t O HP = 435°C; consumption D O HP = 43 tons/h; low-pressure steam ‐ p O = 0.5 MPa; t O LP = 210°C; D O = 13.04 tons/h. The key specifications of the boiler in rated operation mode of the PGU-110 as a function of surrounding air temperature are cited in Table 2. The stationary heat-and-power generating steam turbine was of the T-14/23-4.5/0.18-4 type (one unit) with regulated steam heat extraction built by Kaluga Turbine Plant (Kaluga, Russia) for driving AC electric generator. The key parameters and specifications of the steam turbine are furnished in Table 3. In updating, the GTP was equipped with the SPRINT power enhancing system. The principle of operation of the system was spraying of demineralized water through an injector to increase the mass rate of airflow through the compressor in operation under conditions of elevated external air temperature. The maximum GTP power rises from 46 to 48 MW when the SPRINT system is used. After updating of the PGU-110, thermal tests for determining the installed and maximum capacities were performed and the efficiency of the steam-and-gas plant was calculated.