Superheated steam temperature adjusting system and method suitable for SCR low-load operation

Abstract

The invention discloses a superheated steam temperature adjusting system and method suitable for SCR low-load operation. The system comprises a bypass system arranged between a low-temperature superheater outlet header and a first stage spray type desuperheater, a feed water heater arranged in front of an economizer inlet header, various pipes and valves, and the various pipes and the valves are connected with the steam temperature adjusting system. The steam flow of a low-temperature superheater is adjusted by adjusting the opening degrees of valves of the bypass system, so that part of superheated steam is used for heating economizer inlet fed water, the economizer inlet water temperature is increased, the heat exchange amount of an economizer system is reduced so as to control the fume temperature at an economizer outlet, and the fume temperature which does not reach the SCR operation condition originally at low load can meet the temperature requirement of SCR operation. The problem that a power plant SCR denitration system cannot be operated at low load is solved, and it is guaranteed that emission of nitric oxides in the full-load operation of a power plant meets the requirements.

Description

technical field [0001] The invention relates to a technical method for low-load flue gas denitrification of coal-fired boilers, which belongs to the technical field of coal-fired boiler emission reduction, and specifically refers to a system and method for regulating superheated steam temperature suitable for SCR low-load operation. Background technique [0002] my country's coal-based energy source determines that my country's air pollution is characterized by soot-type pollution. my country's existing coal-fired power generation equipment has a high overall coal consumption for power generation and low energy utilization, which further aggravates the gas emissions and environmental pollution caused by coal combustion. At the same time, my country's coal-fired power plants started late in the control of nitrogen oxide emissions, resulting in a rapid increase in the total amount of nitrogen oxide emissions. After nitrogen oxides enter the atmosphere, under the action of sun...

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Problems solved by technology

[0005] The purpose of the present invention is to provide an existing coal-fired power plant boiler as the transformation object, aiming at the problem that the SCR denitrification system currently in operation cannot be put into operation under low load, and to provide a method to change the arrangement of water spraying and cooling of the existing superheater The system and method can not only adjust the superheated steam temperature, but also meet the purpose of SCR operation under low load, meet the current pollutant emission standards of thermal power plants, and meet the requirements of environmental protection

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