Super or super supercritical coal fired power generation heat system improvement method

Abstract

The invention discloses a measure for improving a supercritical or ultra supercritical coal-burning power generation thermal system belonging to the thermal power generation technical field, relating to the supercritical or ultra supercritical coal-burning power generation thermal system without an economizer and a parameter configuration. The invention concretely comprises following steps of removing the economizer which is requisite for a conventional boiler to simplify the flow of a boiler and reduce the flow resistance of a system and the station service power consumption rate; increasing a primary high-voltage bleeder heater to increase the feed temperature; possibly reducing the exhaust steam pressure and the temperature of a high pressure cylinder to enable the exhaust steam temperature of the high pressure cylinder to be equal or similar to the feed temperature; possibly increasing the temperature of reheat steam on the premise of guarantee of safety; and increasing or providing an air preheater and increasing the temperature of secondary wind to improve the average temperature of heat release of flue gas of the boiler to the cycle fluid of power generation and improve the second-law efficiency of the boiler and the combustion stability of unit coal species changing.

Description

technical field [0001] The invention belongs to the technical field of thermal power generation, and in particular relates to an improvement measure of a super- or ultra-supercritical coal-fired power generation thermal system. Specifically, this measure involves ultra- or ultra-supercritical coal-fired power generation thermal systems without economizers and parameter configuration; removing the economizers necessary for conventional boiler design and adding a high-pressure regenerative heater can simplify the boiler process and reduce System flow resistance and increase the boiler feed water temperature; reduce the exhaust steam pressure of the high-pressure cylinder as much as possible, so that the exhaust steam temperature of the high-pressure cylinder is equal to or equal to the boiler feed water temperature, so as to increase the average temperature of the boiler feed water and reheated steam in a balanced manner; increase or Add an air preheater to increase the temperat...

AI Technical Summary

Problems solved by technology

[0004] However, as the parameters of the unit reach the supercritical pressure and above, the boiler adopts a once-through type. The once-through boiler has no steam drum, and the evaporation process of water in the drum boiler with subcritical and lower parameters no longer occurs during the cycle heat absorption process. The situation has greatly changed. Big change, if the economizer is still installed, the feed water reaches a very high position through the economizer and then goes down to the water wall inlet header at the bottom of the boiler, which will increase the flow resistance and increase the power consumption of the plant

Therefore, the rationality of continuing to install the economizer is gone, and its existence has even become a restrictive factor for improving the efficiency of the second law of the boiler

Images