Exergy Analysis And Universal Exergy Analysis On Thermal System Of Efficient Ultra-supercritical Coal-fired Unit

ABSTRACT:Stable and reliable supply of energy is the basis of economic development. However, the increasingly serious energy situation and worsening environmental problems are always warning usthat the efficient use and conservation of energy and the reduction of environmental damage and pollution are the basic ways to achieve the sustainable development of our economy.For a long time, affected by the structure of energy supply, China’s thermal power plants mainly depend on coal-fired units. After several decades of development,1000MW ultra-supercritical power generation technology has become a mainstream technology in the worldwhose reliability and the thermal efficiency improvement effect to the system have been widely recognized. However, the comprehensive evaluations of1000MW ultra-supercritical power generation technology based on exergy analysis and thermal economy analysis are still relatively few.This paper selected the newly developed domestic efficient1000MW ultra-supercritical units as the main object of study, using the exergy analysis method and universal exergy analysis method to build the model of the thermal system of power plants. Then, the comprehensive evaluation and analysis on the thermal system of efficient1000MW ultra-supercritical coal-fired units and other different types of units were conducted.Based on the thermal system analysis of efficient1000MW ultra-supercritical coal-fired units, the exergy efficiency and universal exergy efficiency have been obtained, and the distribution of exergy loss in the system as well as the causes of exergy loss have been revealed, which provides a basis for optimizing the thermal system of the unit. Meanwhile, compared with the results of300MW subcritical units,600MW supercritical units and conventional1000MW ultra-supercritical units, the exergy efficiency, universal exergy efficiency and sustainable development index of efficient1000MW ultra-supercritical coal-fired units were found better than others unit, which indicated that the efficient1000MW ultra-supercritical units have better utilization of energy and investment and relatively small impact on the environment. Overall, the advantages of efficient1000MW ultra supercritical unit are very significant. It represents the future trend of development of thermal power plant.