Analysis of modern methods of utilization of flue gas heat in thermal power plants

Abstract

Relevance: this study is devoted to the analysis of modern methods of utilization of flue gas heat in thermal power plants (TPPs). The low efficiency of thermal power plants is currently leading to a trend in the world energy systems to switch from steam turbine plants to combined steam-gas plants. However, one of the pressing issues facing the world energy sector is to continue scientific research aimed at modernizing and renovating existing steam turbine thermal power plants and increasing their efficiency.

Aim: to identify methods for reducing heat losses with flue gases of steam turbine plants, develop thermal schemes, and evaluate their effectiveness.

Methods: during the research, more than 30 scientific articles published in the Scopus and Web of Science databases worldwide between 2010 and 2024 were reviewed. Organic Rankine Cycle (ORC), absorption heat pump systems (AHP/OAHP), low-pressure economizers (LPE), heat pipe heat exchangers (HPHE), and thermoelectric generators (TEG) were analyzed as the main technologies.

Results: based on the research, OAIN systems allow recovering up to 80-95% of the available and latent heat in flue gas, while the ORT system can generate power from 220 W to 15 MW with a thermal efficiency of 8-12%. It was determined that the unused heat potential in large thermal power plants in Uzbekistan (Syrdarya, Tashkent, Navoi, Talimarjon) is 120-250 MW. The highest economic performance was recorded for absorption heat pump systems with a payback period of 1.4-2.5 years. This study provides a scientific basis for the introduction of flue gas heat utilization technologies to increase energy efficiency and reduce CO₂ emissions in Uzbekistan.