Wide load denitration system suitable for subcritical thermal power units and control method

Abstract

Belonging to the technical field of wide load denitration, the invention provides a wide load denitration system suitable for subcritical thermal power units and a control method. The system includesan SCR selective catalytic reduction denitration device, a coal economizer water bypass and a feed water flow recirculation device. The system is added with the coal economizer water bypass and the feed water flow recirculation device on the basis of an original SCR denitration device, and two working conditions are optional, i.e. only use of the coal economizer water bypass and simultaneous use of the coal economizer water bypass and the feed water flow recirculation device, the SCR denitration inlet flue gas temperature can be increased by 8DEG C-10DEG C, thus ensuring safe and stable operation of the SCR denitration device above a minimum stable combustion load and within a full load range, and meeting the indicator required by the SCR denitration inlet flue gas temperature, and solvingthe technical problems of low denitration efficiency, over-standard environmental protection parameters, ash clogging of air preheaters and the like in traditional SCR denitration devices.

Description

technical field [0001] The invention belongs to the technical field of wide-load denitrification, and in particular relates to a wide-load denitrification system and control method suitable for subcritical thermal power units. Background technique [0002] With the large-scale grid connection of new energy, in order to better absorb new energy, thermal power units generally reduce the minimum technical output of thermal power units. After the minimum technical output of units is reduced, the boiler is below about 40% of the load, and the economizer is exported. The flue gas temperature is lower than the lower limit required by the catalyst operating temperature, resulting in a decrease in the denitrification efficiency of the SCR selective catalytic reduction method, an increase in the ammonia escape rate, excessive environmental protection parameters, and dust blocking of the air preheater. Safe and stable operation in the full load range above the combustion load. [0003...

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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a wide-load denitrification system and control method suitable for subcritical thermal power units to solve the problems of low denitrification efficiency of traditional SCR denitrification devices, excessive environmental protection parameters, and dust blocking of air preheaters. question

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