Coal-fired thermal power generating unit all-working-condition denitration system and adjusting method

Abstract

The invention relates to a coal-fired thermal power generating unit full-working-condition denitration system and an adjusting method.The system comprises a coal economizer, a main flue and a denitration device which are sequentially communicated, and further comprises a main flue adjusting baffle, a bypass flue device and a bypass flue gas heating device, and the bypass flue device comprises a bypass flue, a bypass flue turn-off baffle and a bypass flue adjusting baffle; the bypass flue gas heating device is arranged in the bypass flue, and the control module is used for controlling the opening degrees of the main flue adjusting baffle, the bypass flue turn-off baffle and the bypass flue adjusting baffle and the working state of the bypass flue gas heating device according to the flue gas temperature at the inlet of the denitration device. The system has the advantages that all-working-condition denitration of the unit is achieved, including the start-stop stage, the low-load stage and the normal-load stage of the unit, the temperature of flue gas at an inlet of a denitration device reaches the allowable temperature of a catalyst or above, emission of NOx is reduced, and a key technology is provided for the coal-fired thermal power unit in the aspect of exploring the lower-load peak regulation capacity.

Description

technical field [0001] The invention relates to the technical field of flue gas denitrification in coal-fired thermal power plants, in particular to a denitrification system and an adjustment method for all working conditions of coal-fired thermal power plants. Background technique [0002] In order to meet the NOx emission concentration requirements of units, most coal-fired units are equipped with SCR denitration devices. The catalyst of the denitration device usually has a working temperature in the range of 300 to 420 °C. If the temperature exceeds the temperature range, the catalyst will not be able to play its due role. When the unit participates in deep peak shaving (low load operation) or the unit needs to start and stop, the inlet flue temperature of the unit's denitration system is usually lower than 300 °C, so it cannot meet the requirements of the normal operation of the denitration system, resulting in the environmental protection index not meeting the standard....

AI Technical Summary

Problems solved by technology

However, these technologies generally belong to the form of internal heat transfer of the unit to increase the flue gas temperature at the SCR inlet to the allowable denitrification temperature, and the temperature increase range is limited.

In the start-up stage of the unit, there is no suitable temperature range for the entire furnace, and it is impossible to achieve full-time denitrification through the heat transfer inside the unit.

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