Flue gas reheating system for coal-fired unit denitration full-load operation

Abstract

The invention relates to a flue gas reheating system for coal-fired unit denitration full-load operation. The flue gas reheating system comprises a flue gas reheating gas burner, a flue gas pipeline system and an air distribution pipeline system. The flue gas reheating gas burner adopts the axial double-spray-opening premixing two-stage ignition design, an ignition device ignites an ignition air gun through electric sparks, and the ignition air gun ignites a main air gun so that it can be ensured that gas is ignited safely and sufficiently burns for heat release under the negative pressure environment. The flue gas temperature rising demand of an inlet of an SCR and the natural gas required consumption are calculated in real time based on a denitration system temperature measuring point feedback signal, by controlling an automatic control adjusting valve on a corresponding pipeline, the flow rate of natural gas and the flow rate of combustion supporting air are adjusted, and it is ensured that the flue gas temperature of the inlet of the SCR meets the denitration requirement. According to the flue gas reheating system, under the working conditions that a coal-fired unit is startedand conducts low-load operation, the flue gas temperature of an inlet of the denitration system can be increased sharply, and normal operation of denitration equipment under the condition of the unitfrom starting to 100% BMCR full-load working can be achieved.

Description

technical field [0001] The invention relates to a flue gas reheating system for denitrification and full-load operation of a coal-fired unit, which is used to increase the flue gas temperature at the SCR inlet of the coal-fired unit to meet the operating conditions of the unit from the start-up of the unit to the 100% BMCR full-load condition. Transportation requirements, belonging to the technical field of boiler environmental protection. Background technique [0002] In recent years, with the rapid growth of installed capacity of clean energy such as wind power and solar energy, my country's power generation structure and power consumption structure have been constantly changing, which requires coal-fired thermal power units to be in low-load operating conditions for a long time to solve the increasingly prominent problems of the power grid. peaking problem. However, as the average load rate of thermal power plants decreases and the low-load operation time increases, when ...

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Problems solved by technology

Each of the above technologies has its own advantages and disadvantages. The flue gas bypass may have problems such as baffle jamming during operation; the classification of economizers is mainly applicable to new units, and the renovation of existing units is limited by the space layout; coal-saving The boiler feed water replacement and 0# high addition technology are used to adjust the temperature from the water side, the system is relatively complex, the investment is relatively high, and there is a problem of reducing boiler efficiency

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