Supplementary resource cooperative control system for flue gas of coal-fired unit

Abstract

The invention provides a supplementary resource cooperative control system for flue gas of a coal-fired unit. The system comprises a flue, an ozone supply unit, an ozone nozzle arranged in the flue and connected with the ozone supply unit, a supplementary washing tower, a liquid ammonia solution supply unit with a liquid ammonia solution tank, a liquid ammonia nozzle arranged in the supplementarywashing tower and connected with the liquid ammonia solution tank, and a byproduct recovery unit. The byproduct recovery unit comprises a fan, a supplementary oxygenation pipeline arranged in the liquid ammonia solution tank, a delivery pump and a dryer. Residual SOx and NOx in tail flue gas of a coal-fired unit can be efficiently removed, desulfurization, denitrification, dust removal and purification of the coal-fired unit are supplemented, and the purpose of further cooperative control over flue gas pollutants is achieved; oxidation denitration is adopted, the oxidation denitration reactionhas no obvious requirement for the temperature, low-temperature denitration is achieved, and therefore the adaptability of the system to temperature is enhanced; and a byproduct obtained after desulfurization and denitrification can be recycled as an ammonia fertilizer, and cooperative matching of emission reduction and resource utilization is realized.

Description

technical field [0001] The invention relates to the field of tail flue gas treatment in coal-fired units, in particular to a supplementary resource-based collaborative control system for the flue gas of coal-fired units. Background technique [0002] In conventional coal-fired units, tail flue gas treatment equipment includes SCR denitrification device, electrostatic precipitator and desulfurization tower, and the flue gas at the outlet of the desulfurization tower is saturated wet flue gas at 50-60 °C. At present, it is required to stipulate that the concentration of air pollutants emitted by coal-fired units shall not be higher than 10, 35, and 50 mg / Nm respectively for smoke, sulfur dioxide, and nitrogen oxides. 3 . [0003] Under the requirements of the current ultra-low emission standards, in order to reverse the public's impression of high pollution and strong emissions from coal-fired units, some provinces, cities and power generation groups have proactively customiz...

AI Technical Summary

Problems solved by technology

Under this standard, the conventional SCR denitrification and wet Ca desulfurization processes are difficult to meet the index requirements, and the power plant needs to invest a huge amount of money to improve the efficiency of the process, and pay a huge price during operation, which affects the economics of boiler operation

[0004] In addition, under the conditions of start-up and low load, the existing flue gas temperature cannot meet the operating temperature requirements of denitrification SCR

In response to the operational flexibility requirements of coal-fired units, various research institutes have proposed a variety of wide-load denitrification transformation technologies, but in general, none of them can achieve denitrification at the start-up stage. Realize denitrification under all working conditions

[0005] Further, the Chinese invention patent application specification with the application publication number CN106000048A discloses a low-temperature desulfurization and denitrification system. The system uses lye to fully absorb pollutants in the exhaust gas through an orifice corrugated packing absorption tower, and the lye Add evaporative concentration cycle to regenerate the solution without discharging waste liquid; but this technology is suitable for medium NO 2 The organic waste gas dominated by NO can not be adapted to the coal-fired flue gas dominated by NO

[0006] Further, the Chinese invention patent application specification with the application publication number CN106334423A discloses a low-temperature denitrification process based on activated carbon materials, which uses activated carbon as a carrier to intercept SO in the denitrification and treatment system 2 , to remove NOx in the denitrification fixed bed reactor to achieve the purpose of simultaneous removal of pollutants; but this process still has certain requirements on the reaction temperature, when the temperature is lower than 80 ° C, the efficiency drops sharply, and the cost of activated carbon is high. Affect further promotion and application

[0007] In summary, there are at least the following problems in the existing technology: poor adaptability to flue gas of coal-fired units, removal of SO 2 and NOx are too expensive, and the denitrification effect needs to be improved

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