Boiler water feeding step heating system adapting to unit wide-load denitration and adjusting method

Abstract

The invention discloses a boiler water feeding step heating system adapting to unit wide-load denitration. The boiler water feeding step heating system comprises a turbine high-pressure cylinder, a turbine intermediate-pressure cylinder, a reheater, a third-stage high-pressure heater, a second-stage high-pressure heater, a first-stage high-pressure heater, a first steam cooler, a second steam cooler, an industrial steam heat exchanger, a third steam cooler, a reheating steam heat exchanger, an economizer and a denitration device. The turbine high-pressure cylinder, the reheater and the turbineintermediate-pressure cylinder are sequentially connected. A deoxidizing water feeding pipe is sequentially connected with the third-stage high-pressure heater, the second-stage high-pressure heater,the first-stage high-pressure heater, the first steam cooler, the second steam cooler, the industrial steam heat exchanger, the third steam cooler, the reheating steam heat exchanger and the economizer. The turbine intermediate-pressure cylinder is connected with a third-stage high-pressure heater steam extracting pipe and an industrial steam extracting pipe. The industrial steam extracting pipeis connected with the industrial steam heat exchanger. A reheating steam extracting pipe is connected with a steam outlet of the reheater and a steam inlet of the reheating steam heat exchanger.

Description

technical field [0001] The invention belongs to the technical field of thermal power flexibility, and in particular relates to a boiler feed water cascade heating system and an adjustment method suitable for unit wide-load denitrification, especially suitable for thermal power plants for unit load peak regulation. Background technique [0002] At present, my country's policies are gradually emphasizing the promotion of new energy sources and reducing the proportion of thermal power units. By the end of 2012, my country had installed wind power capacity of 44.8GW. However, wind power has strong randomness, intermittency, uncontrollability and anti-peaking characteristics, which gradually increases the difficulty of thermal power units in power grid peaking. In order to effectively consume new energy resources, the country has gradually increased the policy requirements for peak regulation of thermal power units. The regulations require that the space for clean energy consum...

AI Technical Summary

Problems solved by technology

The reaction efficiency of the existing SCR denitrification device is seriously reduced when the boiler load is lower than about 50%, which cannot meet the requirements of pollutant discharge standards, and limits the peak-shaving ability of thermal power units.

[0003] At present, this problem is mainly solved through the technical means of transforming the economizer, such as Patent 1: Economizer Sectional Boiler Full Load Low NO X The device and modification method (Patent No. 201510701175.X) solve this problem by dividing the economizer into a high-temperature section, a medium-temperature section, and a low-temperature section, and setting the reaction zone of the denitrification device in the high-temperature section and low-temperature section with higher temperatures. However, the disadvantage of this technology is that the transformation range is relatively large, and the original layout of the boiler tail is compact, which is not suitable for large-scale transformation. In addition, when the load of the unit is high, the flue gas temperature is too high, which makes the flue gas temperature in the reaction zone of the denitrification device A sharp increase, thereby reducing the reaction efficiency of denitrification; Patent 2: A high-efficiency SCR denitrification structure and method that can realize full-load operation (patent number 201710168504.8), through the reaction zone of the denitrification device is divided into the first layer, the second layer First and second level economizers are installed at the corresponding positions to solve this problem, but the biggest disadvantage of this technology is that the transformation is complicated and the transformation range is large, and it is not easy to install in a compact layout. Implementation of Boiler Tail Deployment

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