SNCR-SCR combined denitration system and method based on ammonia nitrogen molar ratio detection and regulation

An ammonia-nitrogen molar ratio and detection system technology, applied in chemical instruments and methods, separation methods, dispersed particle separation, etc., can solve problems such as unsatisfactory, air preheater corrosion, and unreasonable ammonia escape, to eliminate corrosion and Sedimentation problems, reducing catalyst costs, and improving the effect of denitration efficiency

Inactive Publication Date: 2015-12-23
STATE GRID HENAN ELECTRIC POWER ELECTRIC POWER SCI RES INST +2
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  • Abstract
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  • Application Information

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Problems solved by technology

[0003] SCR process uses NH 3 etc. as the reducing agent, on the action line of the catalyst, the NO in the flue gas x Revert to N 2 , the denitrification rate can reach more than 90%, which is the most mature denitrification technology with the highest denitrification efficiency. Under low-load operation conditions for a long time, at this time, the temperature of the flue gas at the inlet of the SCR reactor is lower than the operating temperature of the catalyst, and the denitrification system stops injecting ammonia, which affects the normal operation of the denitrification system of the thermal power plant and affects the flue gas NO. x Emissions and denitrification power price compensation for power plants cannot meet the recent National Energy Administration's full-load denitrification requirements for power plants; 2) SO in flue ga

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  • SNCR-SCR combined denitration system and method based on ammonia nitrogen molar ratio detection and regulation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] The device of this embodiment is as described above, and will not be repeated here, wherein the first nozzle 7 is a 4-layer atomization spray gun, 10 are arranged in each layer, the first nozzle 7 is arranged on the inner wall of the boiler, and the temperature of the flue gas is 800-1100°C within the area.

[0037] This example is a 600MW unit, the boiler load is 50%, and the flue gas volume is about 75×10 4 m 3 / h, the NOx concentration in the flue gas is about 320mg / m 3 .

[0038] A SNCR-SCR combined denitrification method based on the detection and regulation of the ammonia nitrogen molar ratio, including the sequential SNCR reaction step and SCR reaction step, the specific steps are as follows:

[0039] (1) The ammonia-containing storage tank 1 adjusts the first nozzle 7 to spray the ammonia-containing solution into the SCNR reaction zone 4 through the first flow meter 2. The ammonia-containing solution is a urea solution with a concentration of 5% to 10% by mas...

Embodiment 2

[0043] The device of this embodiment is as described above, and will not be repeated here, wherein the first nozzle 7 is a 4-layer atomization spray gun, 10 are arranged in each layer, the first nozzle 7 is arranged on the inner wall of the boiler, and the temperature of the flue gas is 800-1100°C within the area.

[0044] The second nozzle 8 is a 3-layer atomization spray gun, and each layer is provided with 3 nozzles. The second nozzle 8 is arranged on the rear wall of the diversion chamber in the flue, in the area where the temperature of the flue gas is 300-410°C.

[0045] In this example, the boiler load is 60%, and the flue gas volume is about 120×10 4 m 3 / h, the NOx concentration in the flue gas is 560mg / m 3 .

[0046] A SNCR-SCR combined denitrification method based on ammonia nitrogen molar ratio detection and regulation, the specific steps are as follows:

[0047] (1) The ammonia-containing storage tank 1 adjusts the first nozzle 7 to spray the ammonia-containin...

Embodiment 3

[0050] The device of this embodiment is as described in Embodiment 2, and will not be repeated here.

[0051] In this example, the boiler load is 80%, and the flue gas volume is about 160×10 4 m 3 / h, the NOx concentration in the flue gas is 620mg / m 3 .

[0052] A SNCR-SCR combined denitrification method based on ammonia nitrogen molar ratio detection and regulation, the specific steps are as follows:

[0053] (1) The ammonia-containing storage tank 1 adjusts the first nozzle 7 to spray the ammonia-containing solution into the SCNR reaction zone 4 through the first flowmeter 2. The ammonia-containing solution is a urea solution with a mass percentage concentration of 10-15% to make the SNCR reaction The ammonia-nitrogen molar ratio at the entrance of zone 4 is 0.8:1; at the same time, the ammonia-containing storage tank 1 adjusts the second nozzle 8 to spray ammonia-containing solution into the SCR reaction zone 6 through the second flow meter 2, so that the second detectio...

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Abstract

The invention belongs to the technical field of controlling atmospheric pollutants exhausted by coal-fired boilers, and particularly relates to an SNCR-SCR combined denitration system and method based on ammonia nitrogen molar ratio detection and regulation. The system comprises an ammonia-containing storage tank, an air preheater, an SNCR reaction zone, an SCR reaction zone, a first detection system, a second detection system, a third detection system and a control system, wherein the SNCR reaction zone is arranged in a boiler furnace, the SCR reaction zone is arranged in a boiler flue, and the first detection system, the second detection system and the third detection system are connected with the control system. The combined denitration system can achieve full-load denitration operation, is high in denitration efficiency and solves the problem of corrosion and deposition of ammonium bisulfate in follow-up equipment.

Description

technical field [0001] The invention belongs to the technical field of controlling air pollutants discharged from coal-fired boilers, and in particular relates to an SNCR-SCR combined denitrification system and method based on ammonia nitrogen molar ratio detection and regulation. Background technique [0002] In order to meet the NOx emission standards of GB13223-2011 "Emission Standards of Air Pollutants for Thermal Power Plants", coal-fired units of thermal power plants, especially to meet the "ultra-clean" emission requirements of coal-fired units proposed by the National Development and Reform Energy 2014 (2093), the coal-fired units Coal units must be equipped with a denitrification system to meet the emission requirements of flue gas nitrogen oxides. In the denitrification process, selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), and SNCR+SCR combined technology are widely used denitrification technologies. [0003] SCR process uses NH ...

Claims

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Application Information

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IPC IPC(8): B01D53/78B01D53/86B01D53/56
Inventor 吴文龙郭阳张小霓董锐锋
Owner STATE GRID HENAN ELECTRIC POWER ELECTRIC POWER SCI RES INST
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