The Main Directions for Improving the Efficiency of the Power Equipment of a CHPP

• Published in: Thermal engineering 2021, Vol.68 (1), p.54-58
• Main Authors: Mikhailov, V. E., Smolkin, Yu. V., Sukhorukov, Yu. G.
• Format: Article
• Language: English
• Subjects: Boilers; Circuit design; Cogeneration; Combined cycle power generation; Combined-Cycle Power Plants and Their Auxiliary Equipment; Design parameters; Efficiency; Electricity; Engineering; Engineering Thermodynamics; Exhaust gases; Flow paths; Gas turbines; Gas-Turbine; Gases; Heat and Mass Transfer; Heat generation; Heat recovery; Mathematical analysis; Modernization; Power plants; Steam turbines; Steam-Turbine; Thermal engineering; Thermodynamic efficiency; Turbines
• ISSN: 0040-6015; 1555-6301
• DOI: 10.1134/S0040601520120046

The article discusses matters concerned with rational use and improvement of the thermal efficiency of operating combined heat and power plants (CHPPs) that form a power and heat generation system under real operating conditions. Factors influencing the CHPP performance indicators, including design solutions, the extent of equipment wear in the course of operation, which is connected with deviations of operating modes from their design parameters, etc. are analyzed. It is shown that decreasing the electricity production by T and PT turbines operating in the condensing cycle, increasing the supply of heat from the uncontrolled extractions of high-efficient condensing turbines, and modernization of the equipment and thermal cycle circuits are an important reserve for improving the thermal efficiency of the operating CHPPs. The specific generation of electricity by CHPPs operating in the cogeneration mode is compared for CHPPs equipped with T-250/300-23.5, T-185-12.8, T-100/110-12.8, and T-175/210-12.8 cogeneration turbines and for various solutions on applying gas turbine units (GTUs) at gas-fired CHPPs, including those containing hot-water boilers heated by exhaust gases, including the version of the fully variable combined cycle plant (CCP) for a capacity of 20–25 MW developed at the All-Russia Thermal Engineering Institute. Modern thermal cycle circuits and calculation methods used in designing the modernized flow paths of CHPP steam turbines are presented. The necessity of applying a systems approach in elaborating the requirements for modernizing particular CHPPs by optimizing the structure of generating capacities is pointed out. Recommendations on improving R and TR turbines (with cogeneration back pressure) and uncontrolled steam extractions from large-capacity condensing turbines are formulated with due regard to the systems approach. The article points out the advantages of electricity generation in the CCP condensing cycle, the effectiveness of domestically produced power-generating GTUs with the electrical capacity equal to 16 or 25 MW equipped with heat-recovery hot water boilers or CCPs equipped with these turbines (provided that gas fuel is available for newly constructed capacities), and also limited scales in which the commissioning of cogeneration CCPs is advisable in areas containing large heat loads.