Coal-fired power plant energy level matching heat integration system based on primary air

Abstract

The invention belongs to the technical field of the design of energy saving equipment for power plants and particularly relates to a coal-fired power plant energy level matching heat integration system based on primary air. A hot primary air bypass is arranged behind a hot primary air outlet of an air preheater, and a plurality of stages of air-water heat exchangers and a plurality of stages of extracted steam condensation type air heaters are additionally arranged. According to the coal-fired power plant energy level matching heat integration system based on the primary air, the high-temperature primary air is obtained through replacement by means of low-temperature smoke and extracted steam of a low-pressure cylinder of a steam turbine based on the energy level matching and gradient utilization principle so as to participate in the backheating process. Compared with a traditional power plant steam-water system, the coal-fired power plant energy level matching heat integration system based on the primary air breaks the traditional machine-furnace boundary, the primary air is innovatively used for participating the backheating process of the steam turbine, the heat integration level of a unit heat system is increased, increasing of the heat transfer efficiency in multiple links of the steam-water system is achieved, the acting potential of high-grade energy is exploited more sufficiently, and the purposes of improving the energy utilization efficiency and increasing the energy consumption level of a unit are achieved.

Description

technical field [0001] The invention belongs to the technical field of power station energy-saving equipment design, and in particular relates to an energy-level matching heat integration system of a coal-fired power station surrounding primary wind. Background technique [0002] In existing power plant equipment, high-pressure heaters, deaerators and low-pressure heaters are generally used to extract steam from the steam turbine to heat the condensate in the system, which is the traditional "regeneration" process. This part of the steam leaves the cylinder of the steam turbine and will not be able to continue to do work. However, steam extraction can also increase the temperature of the feed water, and at the same time reduce the heat transfer temperature difference of the relevant heat transfer surfaces of the boiler, which can significantly reduce the heat transfer of the boiler. damage, but also helps to improve the operating safety of the unit. Therefore, the heat rec...

AI Technical Summary

Problems solved by technology

However, according to the theory of equivalent enthalpy drop, there are obvious differences in the extraction efficiencies of steam extraction at each stage of the steam turbine, that is, the ratio of the heat energy of the displaced extraction steam into useful energy is significantly different. For example, the extraction efficiency of high-pressure cylinder extraction can reach More than 50%, while the minimum extraction efficiency of low-pressure cylinder extraction may be less than 10%

However, the traditional waste heat utilization can only squeeze out the low-pressure cylinder to extract steam, and the energy-saving potential is very limited

Images