System for improving denitration operation rate of Siemens 1000MW/600MW ultra-supercritical unit

Abstract

The invention discloses a system for improving denitration operation rate of a Siemens 1000MW / 600MW ultra-supercritical unit, which comprises a denitration device, a boiler, a high-pressure cylinder and a high-pressure heater, wherein when the unit operates in low load, a feed water heating steam source of the high-pressure heater is switched to a 0-section steam suction system from original 1-section steam suction, the 0-section steam suction system comprises that the steam is sucked out reversely from a supply steam inlet of the high-pressure cylinder, the sucked steam enters a steam cooler to be cooled and decompressed to adapt to safe and feed water temperature requirement of the high-pressure heater after passing through an electric gate and a pneumatic check valve, and the cooled and decompressed steam is divided into A and B branches which are respectively introduced to 1A and 1B high-pressure heaters through electric gates, and the system is provided with dredging pipelines according to the pipe arrangement condition and operation requirements. The system is used for solving the problem that denitration is limited when the Siemens 1000MW / 600MW ultra-supercritical unit is in a low-load operation mode, and is simple and easy to operate, and small in change of the existing structure and low in investment.

Description

technical field [0001] The invention relates to the technical field of denitrification in coal-fired power plants, in particular to a system for improving the denitrification commissioning rate of Siemens 1000MW / 600MW ultra-supercritical units. Background technique [0002] At present, most of the denitrification devices in coal-fired power plants are selective catalytic reduction, and the catalysts used usually have a working temperature range of 300-400 ° C. If the temperature exceeds the range, the catalyst will not be able to play its due role. In the design of conventional thermal power plants, there will be the following problems: when the load of the unit is high, the flue gas temperature at the inlet of the denitrification device (the flue gas temperature at the outlet of the economizer) is just within the normal operating range of the catalyst; The temperature is low, lower than the normal use temperature of the catalyst. This is because, if the flue gas temperatur...

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Problems solved by technology

[0002] At present, most of the denitrification devices in coal-fired power plants are selective catalytic reduction, and the catalysts used usually have a working temperature range of 300-400 ° C. If the temperature exceeds the range, the catalyst will not be able to play its due role.

In the design of conventional thermal power plants, there will be the following problems: when the load of the unit is high, the flue gas temperature at the inlet of the denitrification device (the flue gas temperature at the outlet of the economizer) is just within the normal operating range of the catalyst; The temperature is low, lower than the normal use temperature of the catalyst

The existing Siemens 1000MW / 600MW ultra-supercritical unit feedwater recovery system is designed according to the above principles. When the unit is running at low load, the denitrification device is out of operation due to low feedwater temperature (low smoke temperature at the outlet of the economizer)

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