CN210699513U - Steel rolling heating furnace flue gas denitration system - Google Patents
Steel rolling heating furnace flue gas denitration system Download PDFInfo
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- CN210699513U CN210699513U CN201920518299.8U CN201920518299U CN210699513U CN 210699513 U CN210699513 U CN 210699513U CN 201920518299 U CN201920518299 U CN 201920518299U CN 210699513 U CN210699513 U CN 210699513U
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- flue gas
- heating furnace
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- reducing agent
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Abstract
The utility model discloses a steel rolling heating furnace flue gas denitration system, including the reductant storage device who connects gradually, the reductant is prepared the device, the compressed air device, flue gas supercharging device, the vapourizing unit, injection apparatus and controller, the reductant is prepared the device and is included the circulating pump, electric heater, the counter, water pump and blender, the reductant is prepared the device, the compressed air device and the flue gas supercharging device who links to each other with the heating furnace pass through the vapourizing unit and link to each other in the injection apparatus of heating furnace preheating section and heating section junction, reductant storage device, the reductant is prepared the device, vapourThe chemical device and the injection device are both electrically connected with the controller; the utility model discloses have to conventional burning heating furnace, do not add any auxiliary condition, utilized the quick thermolysis NH of temperature of the inside flue gas self of heating furnace3With NO in the flue gasxReduction to N2And H2O, does not generate any secondary by-product, occupies small area, has low operation cost, good stability, simple operation and high safety factor.
Description
Technical Field
The utility model belongs to the technical field of industry flue gas nitrogen oxide reduces discharging (denitration), especially, relate to a steel rolling heating furnace flue gas denitration system.
Background
The steel rolling heating furnace is an industrial furnace and mainly used for heating steel billets by heat generated by fuel combustion and generating a haze nucleating agent NO in the combustion processx. At present, there are more than 8000 rolled steel heating furnaces in China, and the average NO of each heating furnacexAnnual emission of more than 50t, national furnace annual NOxThe discharge amount exceeds 40 ten thousand t, and NO is applied to a steel rolling heating furnacexThe treatment mostly adopts the circulating flue gas low-nitrogen combustion technology to reduce NO at the sourcexGeneration of NOxThe content can be reduced to 200mg/Nm3Below, but China for NOxThe emission of the treatment standard industrial kiln is required to be 150mg/Nm3The requirement for ultra-low emissions is still not met below. If reprocess the transformation to current heating furnace, if install flue gas afterbody denitrification facility and unite the cooperation additional, operation and once investment expense are high, and area is big, and the transformation cycle is long, and it can produce the danger useless to add the catalyst simultaneously, increases processing cost greatly.
In view of this, the present invention is especially provided.
SUMMERY OF THE UTILITY MODEL
To the problem that exists among the prior art, the utility model aims at providing a steel rolling heating furnace flue gas denitration system adopts SNCR technique to reduce NOxThe emission concentration of the fuel is particularly suitable for a conventional combustion heating furnace, and NH is rapidly thermally decomposed by utilizing the self temperature of the flue gas in the heating furnace on the premise of not adding any auxiliary condition3With NO in the flue gasxReduction to N2And H2O, does not generate any secondary by-product, occupies small area, has low operation cost, good stability, simple operation and high safety factor.
In order to achieve the purpose, the utility model provides a steel rolling heating furnace flue gas denitration system, including reductant storage device, reductant preparation device, compressed air device, flue gas supercharging device, vapourization device, injection apparatus and the controller that connect gradually, reductant preparation device includes circulating pump, electric heater, counter, water pump and the blender that links to each other with reductant storage device export, reductant storage device loops through circulating pump, electric heater and metering device formation circulation circuit, the blender import links to each other with water pump and counter respectively, the export of blender links to each other with vapourization device; the device is prepared to the reductant, compressed air device and the flue gas supercharging device who links to each other with the heating furnace link to each other through vaporizing device and the injection apparatus that circumference set up in the heating furnace preheating section and heating section junction, all through the tube coupling that is equipped with control flap between the device, the reductant is aqueous ammonia or urea, reductant storage device, reductant preparation device, vaporizing device, injection apparatus and control flap all are connected with the controller electricity.
Preferably, the water pump further comprises a pressure control device for controlling the pressure of the water pump;
preferably, the compressed air device is an air compressor;
preferably, the flue gas supercharging device is a supercharging fan connected with the heating furnace through a flue gas channel;
preferably, the vaporization apparatus is a cyclone vaporizer;
preferably, the reducing agent preparation device is used for preparing the reducing agent into 10% ammonia water or 10% urea.
The utility model provides a pair of steel rolling heating furnace flue gas deNOx systems has following beneficial effect:
through arranging a plurality of reducing agent injection points between the heating section and the preheating section of the heating furnace, firstly, the preheating section of the heating furnace is not provided with a burner and has NO combustion reaction, the temperature of the whole interval is 700-1000 ℃ in the SNCR reaction interval, and the high temperature existing in the prior art and the condition that the reducing agent is oxidized into NO are effectively avoidedxNO in flue gasxThe content is not reduced but increased; low temperature, insufficient reaction, reducing agent loss, adverse effect on downstream equipment and even new pollution. Secondly, spraying urea solution at the joint of the heating section and the soaking section, fully mixing the urea solution with the flue gas in the furnace and enabling the urea solution to enter a flue until the urea solution reaches a flue gas outlet for about 5s for denitration reaction, and before the urea solution reaches a heat exchanger, urea and NO are sprayedxFully react, and have the characteristics after mixingSufficient heat exchange space and sufficient reaction time, and ensures NH3And the flue gas is fully mixed uniformly, so that the denitration efficiency is greatly improved.
Drawings
FIG. 1 is the utility model provides a steel rolling heating furnace flue gas deNOx systems's system block diagram.
Fig. 2 is the utility model provides a heating furnace and injection apparatus of steel rolling heating furnace flue gas deNOx systems's structural schematic diagram.
FIG. 3 is a graph of experimental results of different temperatures of the SNCR system on denitration efficiency.
In the figure:
1. the system comprises a heating furnace 101, a heating section 102, a preheating section 103, a flue 2, a vaporizing device 3, a mixer 4, a metering device 5, a water pump 51, a pressure control device 6, an electric heater 7, a circulating pump 8, a reducing agent storage device 9, a urea unloading pump 10, an injection device 11, a compressed air device 12, a flue gas supercharging device 121 and a flue gas channel.
Detailed Description
The present invention will be further described with reference to the following specific embodiments and accompanying drawings to facilitate understanding of the present invention.
As shown in fig. 1-3, for the utility model provides a steel rolling heating furnace flue gas denitration system, including reductant storage device 9, reductant preparation device, compressed air device 11, flue gas supercharging device 12, vaporizer 2, injection apparatus 10 and the controller that connect gradually, reductant storage device 9 is the reductant holding vessel, compressed air device 11 is air compressor, flue gas supercharging device 12 is the booster fan who is connected with heating furnace 1 through flue gas passageway 121, vaporizer 2 is the whirl vaporizer; the reducing agent preparation device comprises a circulating pump 7, an electric heater 6, a metering device 4, a water pump 5 and a mixer 3 which are connected with an outlet of a reducing agent storage device 8, the reducing agent storage device 8 forms a circulating loop with the metering device 4 through the circulating pump 7 and the electric heater 6 in sequence, and the water pump 5 is connected with a pressure control device for controlling the pressure of the water pump through a pipeline provided with a control valve; an inlet of the mixer 3 is respectively connected with a water pump 5 and a metering device 4, detection equipment such as a liquid level meter, a thermometer and a pressure sensor is arranged in the mixer 3, the concentration of the reducing agent is sprayed according to the requirement for preparation, the data in the mixer is monitored in real time, and an outlet of the mixer 3 is connected with the vaporizing device 2; the device comprises a reducing agent preparation device, a compressed air device, a flue gas supercharging device 12 connected with the heating furnace 1, and an injection device 10 circumferentially arranged at the joint of a preheating section 102 and a heating section 101 of the heating furnace 1 through a vaporization device 2, wherein the devices are connected through a pipeline provided with a control valve, the reducing agent is ammonia water or urea, and a reducing agent storage device 8, the reducing agent preparation device, the vaporization device 2, the injection device 10 and the control valve are electrically connected with a controller.
A flue gas denitration process of a steel rolling heating furnace is operated according to the following steps:
1. the reducing agent is unloaded into a reducing agent storage tank 8 through a reducing agent unloading pump 9;
2. conveying the reducing agent in a reducing agent storage tank 8 to a measuring device 4 through a circulating pump 7 and an electric heater 6 for metering and outputting, mixing and diluting the reducing agent with water output by a water pump 5 in a mixer 3 to obtain a reducing agent of 10% ammonia water or 10% urea solution, and conveying redundant reducing agent in the metering device 4 back to the reducing agent storage tank 8 through a pipeline;
3. the prepared reducing agent, compressed air and pressurized flue gas are sent into a vaporizing device 2 to be vaporized, the solution is completely vaporized by the high-temperature pressurized gas, and ammonia is converted into NH3 gas;
4. the vaporized gas is sent into the injection device 10 through pressurized air, and the vaporized gas is injected into the heating furnace 1 through the controller according to the injection amount adjusted by the concentration of NOx so as to be fully mixed with the flue gas;
5. the mixed flue gas moves from the heating furnace 1 to the flue 103, and NH simultaneously3Sufficiently reducing NOx to produce N2And H2And O, discharging the product into the atmosphere along with the flue gas.
As shown in figure 3, the temperature of the hearth of the preheating section and the heating section of the heating furnace is 700-1000 ℃, and NH is carried out under the action of no catalyst3Or urea and other amino reducing agents can selectively reduce NO in the smokexSubstantially free of O in the flue gas2The main reaction is as follows:
when ammonia is the reducing agent:
4NH3+6NO→5N2+6H2O
a positive competing reaction can occur at higher temperatures:
4NH3+5O2→4NO+6H2O
at this time, the denitrification is incomplete.
Urea (NH)2CONH2) When used as a reducing agent:
(NH2)2CO→2NH2+2CO
NH2+2NO→N2+H2O
CO+NO→N2+CO2
therefore, the present invention provides an improvement in NO affecting selective non-catalytic reduction (SNCR)xFactors of the reduction ratio: selection of the point of injection of the reducing agent and the residence time such that NH3With NOxMixing the reaction thoroughly to react NOxReduction to N2And H2And O, the reaction time is prolonged to a great extent (more than 5 seconds), and the denitration efficiency is greatly improved. Wherein, the injection point of the reducing agent is selected by arranging the injection device on the upper heating and the lower heating of the connection section (the temperature is between 700 ℃ and 1000 ℃) of the preheating section and the heating section, so as to ensure that the reducing agent enters a temperature zone which is suitable for reaction in the hearth. The temperature is high, the reducing agent is oxidized into NOx, and the content of NOx in the flue gas is not reduced but increased; the temperature is low, the reaction is insufficient, the reducing agent is lost, and the adverse effect and even new pollution are generated on downstream equipment. Meanwhile, a vaporized reducing agent solution is uniformly sprayed into the connection section of the preheating section and the heating section through a spraying device, the vaporized reducing agent solution is fully mixed with the flue gas in the furnace and enters the flue, and the reducing agent and NO are mixed before reaching the heat exchangerxThe full reaction, the reaction time (more than 5 seconds) is greatly prolonged, and the denitration efficiency is greatly improved. NH is caused by the temperature and the residence time of the flue gas in the heating furnace3With NOxMixing the reaction thoroughly to react NOxReduction to N2And H2O。
The present invention has been described in detail with reference to specific embodiments, and the description of the embodiments is only for the purpose of helping understanding the core idea of the present invention. It should be understood that any obvious modifications, equivalents and other improvements made by those skilled in the art without departing from the spirit of the present invention are intended to be included within the scope of the present invention.
Claims (6)
1. A steel rolling heating furnace flue gas denitration system is characterized by comprising a reducing agent storage device, a reducing agent preparation device, a compressed air device, a flue gas supercharging device, a vaporizing device, an injection device and a controller which are sequentially connected, wherein the reducing agent preparation device comprises a circulating pump, an electric heater, a meter, a water pump and a mixer which are connected with an outlet of the reducing agent storage device; the device is prepared to the reductant, compressed air device and the flue gas supercharging device who links to each other with the heating furnace link to each other through vaporizing device and the injection apparatus that circumference set up in the heating furnace preheating section and heating section junction, all through the tube coupling that is equipped with control flap between the device, the reductant is aqueous ammonia or urea, reductant storage device, reductant preparation device, vaporizing device, injection apparatus and control flap all are connected with the controller electricity.
2. The flue gas denitration system of a steel rolling heating furnace according to claim 1, further comprising a pressure control device for controlling the pressure of the water pump.
3. The flue gas denitration system of a steel rolling heating furnace according to claim 1, wherein the air compression device is an air compressor.
4. The flue gas denitration system of a steel rolling heating furnace according to claim 1, wherein the flue gas boosting device is a booster fan connected with the heating furnace through a flue gas channel.
5. The flue gas denitration system of a steel rolling heating furnace according to claim 1, wherein the vaporizing device is a cyclone vaporizer.
6. The flue gas denitration system of a steel rolling heating furnace according to claim 5, wherein said reducing agent preparation device is used for preparing a reducing agent into 10% ammonia water or 10% urea.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920518299.8U CN210699513U (en) | 2019-04-17 | 2019-04-17 | Steel rolling heating furnace flue gas denitration system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920518299.8U CN210699513U (en) | 2019-04-17 | 2019-04-17 | Steel rolling heating furnace flue gas denitration system |
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| CN210699513U true CN210699513U (en) | 2020-06-09 |
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| CN201920518299.8U Active CN210699513U (en) | 2019-04-17 | 2019-04-17 | Steel rolling heating furnace flue gas denitration system |
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