Operating temperature control device for SCR (semiconductor control rectifier) denitration reactor of thermal power plant and control method of operating temperature control device

Abstract

The invention relates to an operating temperature control device for an SCR (semiconductor control rectifier) denitration reactor of a thermal power plant and a control method of the operating temperature control device. At present, no convenient, flexible and effective control device and method for guaranteeing operating temperature of the SCR denitration reactor exists when exhaust gas temperature of the thermal power plant changes fiercely. The operating temperature control device comprises a coal economizer, a flue, the SCR denitraton reactor, a boiler, an evaporator, a water feed pump and a low-pressure steam pumping pipe, and is characterized by further comprising a high-pressure heater bypass, a high-pressure heater bypass stop valve, a coal economizer bypass, a coal economizer bypass stop valve, a coal economizer bypass electric adjusting valve, a high-pressure heater bypass control circuit, a coal economizer bypass control circuit, an SCR denitration reactor inlet smoke temperature measuring circuit and a controller. A temperature sensor is arranged at an inlet of the SCR denitration reactor, and the controller is connected to the temperature sensor through the SCR denitration reactor inlet smoke temperature measuring circuit. The operating temperature control device is simple in structural design, and convenient and flexible to use.

Description

technical field [0001] The invention relates to a working temperature control device of an SCR denitration reactor in a thermal power plant and a control method thereof, which can control the flue gas temperature at the inlet of the SCR denitration reactor within an optimal range. Background technique [0002] At present, thermal power plants generally use SCR denitrification reactors to control the emission of nitrogen oxides. The removal efficiency of SCR denitrification reactors largely depends on the temperature of the flue gas entering the reactor. The effective operating temperature range of the SCR denitrification reactor is about 300°C to 400°C. Usually, different catalysts have different optimal operating temperature values. The fluctuation of this optimal operating temperature value by about 20°C is the optimum temperature for the catalyst. In the actual operation process, the flue gas temperature at the inlet of the SCR denitrification reactor is lower than or exc...

AI Technical Summary

Problems solved by technology

In addition, when the fuel changes and the combustion conditions change, it is also easy for the fluctuation of the exhaust gas temperature to exceed the optimum working temperature range of the SCR denitrification reactor.

[0004] When the fluctuation of exhaust gas temperature in a thermal power plant exceeds the optimum working temperature range of the SCR denitrification reactor, in order to ensure the denitrification efficiency of the SCR denitrification reactor and meet the requirements of environmental protection emissions, the usual control method is to increase the injection amount of the reducing agent, so that As a result, the consumption of reducing agent increases, the operating cost of the SCR denitrification reactor increases, and it also affects the working life of the SCR denitrification reactor

In addition, the increase in the amount of reductant injection is likely to increase the escape of reductant, which will have adverse effects on downstream equipment

[0005] There are also other methods for controlling the flue gas temperature at the inlet of the SCR denitrification reactor. For example, in the Chinese patent whose publication date is November 21, 2007 and whose publication number is CN101074771A, a method for controlling the temperature of the selective catalytic reactor is disclosed. A multi-pass economizer having at least two tubular structures that reduces feedwater flow through at least one tubular structure and reduces feedwater flow through the remaining tubular structures and a method of the present invention. Reduce the heat transferred from the flue gas to achieve the purpose of increasing the flue gas temperature; the above technology can only increase the flue gas temperature when the flue gas temperature is low, but cannot reduce the flue gas temperature when the flue gas temperature is high; in addition , the above-mentioned technology needs to change the existing economizer structure, the reconstruction project is costly and the workload is heavy

[0006] To sum up, there is currently no control device and control method with a reasonable structural design that can conveniently, flexibly and effectively ensure the working temperature of the SCR denitrification reactor when the exhaust gas temperature of the thermal power plant changes drastically.

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