阅读说明：本技术 一种tft-lcd液晶玻璃窑炉氮氧化物的控制方法 (Control method of nitric oxide in TFT-LCD (thin film transistor-liquid crystal display) liquid crystal glass kiln ) 是由 彭寿 张冲 李兆廷 任红灿 陈英 王国全 邵廷荣 黄德伟 段美胜 于 2020-12-16 设计创作，主要内容包括：本发明公开一种TFT-LCD液晶玻璃窑炉氮氧化物的控制方法,具体包括减少窑炉中氮气的引入,具体过程：控制置于液晶玻璃窑炉两侧上的第四对烧枪在正常生产时通入氧气对第四对烧枪进行冷却或者在窑炉过完大火后正常生产前,拆除第四对烧枪,然后用耐火材料将第四对烧枪口封住,以及选用热值高的工业用天然气作为燃料,改变置于液晶玻璃窑炉端部烟道上的烟气冷却方法,以及控制液晶玻璃窑炉中氧气和天然气比例为2.1-2.4:1等手段大幅度的降低窑炉氮氧化物的排放；不仅满足待实施的国家新的环保排放标准,且不需要对硬件设备进行大的改造,就能达到环保排放要求,具有较好的经济和社会价值。(The invention discloses a method for controlling nitric oxides in a TFT-LCD liquid crystal glass kiln, which specifically comprises the following steps of reducing the introduction of nitrogen in the kiln: controlling a fourth pair of burning guns on two sides of the liquid crystal glass kiln to introduce oxygen to cool the fourth pair of burning guns during normal production or removing the fourth pair of burning guns before normal production after the kiln has been subjected to intense fire, sealing the openings of the fourth pair of burning guns by refractory materials, selecting industrial natural gas with high heat value as fuel, changing a flue gas cooling method arranged on a flue at the end part of the liquid crystal glass kiln, controlling the ratio of oxygen to natural gas in the liquid crystal glass kiln to be 2.1-2.4:1 and the like to greatly reduce the emission of nitrogen oxides in the kiln; the method not only meets the new environmental-protection emission standard of the country to be implemented, but also can meet the environmental-protection emission requirement without greatly modifying hardware equipment, and has better economic and social values.)

1. A control method of TFT-LCD liquid crystal glass kiln nitrogen oxides is characterized by comprising the following specific processes of reducing the introduction of nitrogen in a kiln, specifically comprising the introduction of cooling and purifying compressed air, and reducing the introduction of the cooling and purifying compressed air: and controlling the fourth pair of burning guns on the two sides of the liquid crystal glass kiln to introduce oxygen to cool the fourth pair of burning guns during normal production.

2. The method for controlling the nitric oxides in the TFT-LCD liquid crystal glass kiln according to claim 1, wherein the reduction of the introduction of nitrogen in the kiln further comprises controlling the introduction amount of nitrogen in fuel, and the specific process comprises the following steps: industrial natural gas with high heat value is selected as fuel.

3. The method for controlling the nitric oxide in the TFT-LCD liquid crystal glass kiln as claimed in claim 1, further comprising changing a flue gas cooling method on a flue at the end of the liquid crystal glass kiln, and cooling air entering the flue by changing the flue gas cooling method into a method of cooling the flue gas by a cooling water coil.

4. The method for controlling the nitric oxide in the TFT-LCD liquid crystal glass kiln according to claim 1, wherein the method for controlling the nitric oxide in the liquid crystal glass kiln further comprises the steps of controlling the ratio of oxygen to natural gas introduced into the liquid crystal glass kiln, wherein the ratio of oxygen: the natural gas is 2.1-2.4: 1.

5. The method for controlling the nitrogen oxides in the TFT-LCD liquid crystal glass kiln according to any one of claims 1-4, wherein the specific process of reducing the introduction of the cooling and purifying compressed air further comprises the following steps: and when the kiln normally produces the fire after passing the big fire, the fourth pair of burning guns is dismantled, and then the fourth pair of burning gun openings are sealed by refractory materials.

6. The burning torch control system of the above claims 1-4, comprising a plurality of pairs of burning torches arranged at two sides of the liquid crystal glass kiln and having a consistent structure, wherein the first pair of burning torches, the second pair of burning torches, the third pair of burning torches and the fourth pair of burning torches are arranged along the direction away from the flue; each burning gun in each pair of burning guns is communicated with a natural gas pipeline, an oxygen pipeline and a purified compressed air pipeline, wherein a natural gas control valve is arranged on the natural gas pipeline, an oxygen control valve is arranged on the oxygen pipeline, and a purified compressed air valve is arranged on the purified compressed air pipeline; the natural gas control valve, the oxygen control valve and the purification compressed air valve on each burning gun of each pair of burning guns are connected with the kiln combustion control system to form a control loop, and the kiln combustion control system independently controls the adjustment of the natural gas control valve, the oxygen control valve and the purification compressed air valve of each burning gun of the pair of burning guns; the plurality of burning guns correspond to the control loops of the plurality of kiln burning control systems.

7. The burning torch control system of claim 6, wherein during normal production, the furnace combustion control system corresponding to the fourth pair of burning torches is controlled to issue a command, oxygen is introduced into the fourth pair of burning torches of the liquid crystal glass furnace, the natural gas control valve in the fourth pair of burning torches is closed, the purified compressed air valve is closed, and the oxygen control valve is opened.

8. The lance burning control system according to claim 6, wherein during normal production, the kiln burning control system corresponding to the first pair of lances is controlled to give out an instruction to control the first pair of lances to be introduced with oxygen and natural gas; closing a purified compressed air valve in the first pair of burning guns, opening an oxygen control valve and opening a natural gas control valve; and similarly, controlling the second pair of burning guns to be filled with oxygen and natural gas, and controlling the third pair of burning guns to be filled with oxygen and natural gas.

Technical Field

The invention belongs to the technical field of glass production kiln equipment, and particularly relates to a control method of nitric oxides in a TFT-LCD liquid crystal glass kiln.

Background

With the increasing severity of air pollution, the emission reduction of nitrogen oxides has been paid more attention and more attention, in the glass production process, the nitrogen oxides are the smoke emission of a TFT-LCD liquid crystal glass substrate production kiln, the environmental protection department has requirements on the emission value, the proportion of nitrate in the TFT-LCD liquid crystal glass substrate raw materials is small, most of the nitrogen oxides generated by the kiln are air introduced when a kiln burning gun and kiln smoke are protected and the temperature of the kiln smoke is reduced, and part of the nitrogen oxides are air or nitrogen introduced when the heat value is adjusted in natural gas (civil natural gas) and nitrogen oxides generated in a high-temperature environment. Although the nitrogen oxide discharged by the kiln in the prior art meets the existing national environmental protection emission standard, the nitrogen oxide discharged by the kiln in the prior art does not meet the technical requirement of new national environmental protection emission to be implemented, namely the discharge amount of the nitrogen oxide in the flue gas of the kiln in the prior art is about twice of the new national environmental protection emission standard; the large technical reconstruction of the ignited continuous production kiln is high in cost and difficulty, and an economical and feasible technical scheme is required to be found for solving the existing environmental protection problem, but the kiln must meet the new national environmental protection emission standard to be implemented.

Disclosure of Invention

The technical problem solved by the invention is as follows: the invention provides a method for controlling nitric oxides in a TFT-LCD liquid crystal glass kiln.

The technical scheme adopted by the invention is as follows:

a control method of TFT-LCD liquid crystal glass kiln nitrogen oxides comprises the steps of reducing the introduction of nitrogen in a kiln, specifically comprising the steps of reducing the introduction of cooling and purifying compressed air, and reducing the introduction of cooling and purifying compressed air: and controlling the fourth pair of burning guns on the two sides of the liquid crystal glass kiln to introduce oxygen to cool the fourth pair of burning guns during normal production.

Preferably, the reducing of nitrogen gas introduction in the kiln further comprises controlling nitrogen introduction amount in the fuel, and the specific process is as follows: industrial natural gas with high heat value is selected as fuel.

Preferably, the method for controlling the nitrogen oxide in the liquid crystal glass kiln further comprises the step of changing a flue gas cooling method arranged on a flue at the end part of the liquid crystal glass kiln, and cooling air gathered in the flue by a cooling water coil pipe to reduce the temperature of the flue gas.

Preferably, the method for controlling the nitrogen oxide in the liquid crystal glass kiln further comprises the step of controlling the ratio of oxygen to natural gas introduced into the liquid crystal glass kiln, wherein the ratio of oxygen: the natural gas is 2.1-2.4: 1.

Preferably, the specific process of reducing the introduction of the cooling and purifying compressed air further comprises: and when the kiln normally produces the fire after passing the big fire, the fourth pair of burning guns is dismantled, and then the fourth pair of burning gun openings are sealed by refractory materials.

The burning gun control system comprises a plurality of pairs of burning guns with consistent structures arranged on two sides of the liquid crystal glass kiln, and a first pair of burning guns, a second pair of burning guns, a third pair of burning guns and a fourth pair of burning guns are respectively arranged along the direction far away from the flue; each burning gun in each pair of burning guns is communicated with a natural gas pipeline, an oxygen pipeline and a purified compressed air pipeline, wherein a natural gas control valve is arranged on the natural gas pipeline, an oxygen control valve is arranged on the oxygen pipeline, and a purified compressed air valve is arranged on the purified compressed air pipeline; the natural gas control valve, the oxygen control valve and the purification compressed air valve on each burning gun of each pair of burning guns are connected with the kiln combustion control system to form a control loop, and the kiln combustion control system independently controls the adjustment of the natural gas control valve, the oxygen control valve and the purification compressed air valve of each burning gun of the pair of burning guns; the plurality of burning guns correspond to the control loops of the plurality of kiln burning control systems.

Preferably, during normal production, the kiln combustion control system corresponding to the fourth pair of burning guns sends out an instruction, oxygen is introduced into the fourth pair of burning guns of the liquid crystal glass kiln, the natural gas control valve in the fourth pair of burning guns is closed, the purification compression air valve is closed, and the oxygen control valve is opened.

Preferably, during normal production, the kiln combustion control system corresponding to the first pair of burning guns sends out an instruction to control the first pair of burning guns to introduce oxygen and natural gas; closing a purified compressed air valve in the first pair of burning guns, opening an oxygen control valve and opening a natural gas control valve; and similarly, controlling the second pair of burning guns to be filled with oxygen and natural gas, and controlling the third pair of burning guns to be filled with oxygen and natural gas.

Compared with the prior art, the invention has the following beneficial effects:

1. according to the control method of the nitrogen oxide in the kiln, natural gas with a high heat value and without heat regulation is selected, and nitrogen or air is generally supplemented to the natural gas through heat regulation, so that the nitrogen or air mixed in the natural gas can be reduced by selecting the natural gas with the high heat value and without heat regulation; the medium of cooling gas of a fourth pair of burning guns of the kiln is changed or the fourth pair of burning guns are removed, so that nitrogen is reduced from entering a high-temperature environment of the kiln to generate nitrogen oxides; and then, by using a method of replacing air with water as a method for reducing the temperature of the flue gas and a method of properly reducing the volume ratio of oxygen to natural gas, the method can avoid the production of nitrogen oxide by mixing high-temperature flue gas and air, isolate the material condition of nitrogen oxide produced by a kiln, greatly reduce the generation of nitrogen oxide and even meet the national environmental protection emission standard to be implemented.

2. The method for controlling the nitrogen oxide in the kiln can meet the new national environmental protection emission standard without carrying out large technical transformation on the kiln and accessory equipment, can save a large amount of equipment investment related to environmental protection treatment, and particularly can meet the requirement of environmental protection emission and save fixed investment cost while the service life of the residual equipment can be continuously produced for the established production line.

Drawings

FIG. 1 is a schematic cross-sectional view of a kiln;

FIG. 2 is a schematic view of a longitudinal section of the furnace;

FIG. 3 is a schematic view of the cooling of any pair of burning guns.

Wherein, the names corresponding to the reference numbers are:

1-liquid crystal glass kiln; 2-burning torch, 201-first pair of burning torch, 202-second pair of burning torch, 203-third pair of burning torch, 204-fourth pair of burning torch, 3-flue, 301-brick flue, 302-steel flue, 4-cooling water coil, 5-natural gas pipeline, 6-oxygen pipeline, 7-purified compressed air pipeline, 8-kiln burning control system.

Detailed Description

The present invention will be further described with reference to the following description and examples, which include but are not limited to the following examples.

Examples

The liquid crystal glass kiln structure is shown in fig. 1-2, a flue 3 is arranged at the end part of a liquid crystal glass kiln 1, a plurality of pairs of burning guns 2 are uniformly distributed at two sides of the liquid crystal glass kiln 1, and a first pair of burning guns 201, a second pair of burning guns 202, a third pair of burning guns 203 and a fourth pair of burning guns 204 are respectively arranged along the direction far away from the flue; and the flue 3 is provided with a cooling water coil pipe 4, and the flue 3 comprises a brick flue 301 connected with the end part of the liquid crystal glass kiln 1 and a steel flue 302 connected with the brick flue 301 in a perpendicular mode. The method for controlling the nitric oxide in the TFT-LCD liquid crystal glass kiln 1 with the structure comprises the following steps: the method comprises the steps of controlling the introduction of nitrogen in the kiln, changing a flue gas cooling method arranged on a flue at the end part of the liquid crystal glass kiln, reducing the temperature of the flue gas by changing the way that air is converged into the flue, namely, reducing the temperature of the flue gas by a cooling water coil, controlling the volume ratio of the combustion of natural gas and oxygen, debugging the working technical state of a combustion control system and the like.

As shown in fig. 1 and fig. 2, the liquid crystal glass controls the introduction of nitrogen in the kiln, including controlling the introduction amount of nitrogen in the fuel and reducing the introduction of purified compressed air:

firstly, controlling the introduction amount of nitrogen in the fuel is the control of nitrogen in the fuel: in the invention, natural gas without heat value adjustment is used, nitrogen or air is prevented from being brought in when the natural gas is subjected to heat adjustment, namely, the nitrogen enters a high-temperature furnace along with the natural gas through the first pair of burning guns 201, the second pair of burning guns 202 and the third pair of burning guns 203 and reacts with oxygen to generate nitrogen oxide.

Thirdly, since the fourth pair of burning guns 204 in the liquid crystal glass kiln 1 is only used before normal production of the kiln or after cold repair, and in the prior art, the fourth pair of burning guns 204 are cooled by purified compressed air during normal production to avoid high-temperature damage, therefore, reducing the purified compressed air in the cooling gas to control nitrogen can be realized by two methods, which specifically include:

the first method comprises the following steps: as shown in fig. 1, 2 and 3, in the prior art, the fourth pair of burning guns 204 are protected by purified compressed air during normal production to avoid high-temperature damage, the purified compressed air is adopted for cooling, oxygen is introduced into the fourth pair of burning guns 204 for cooling, and after the fourth pair of burning guns 204 are cooled by the oxygen, the discharge amount of nitrogen oxides in the kiln of my department is immediately reduced by about 50-70%, so that the effect is very obvious; the second method comprises the following steps: or the fourth pair of burning guns 204 is directly dismantled, the fourth pair of burning guns 204 are dismantled before the liquid crystal glass kiln normally produces after the liquid crystal glass kiln is over the fire, and the burning gun ports are sealed by refractory materials after the fourth pair of burning guns 204 are dismantled.

Thirdly, changing the method for reducing the flue gas temperature in the liquid crystal glass kiln 1, namely, changing the flue gas temperature from the way of importing air into the flue 3 into the cooling water coil 4 to reduce the flue gas temperature, because the flue 3 of the TFT-LCD liquid crystal glass kiln has the main structure of the steel flue 302, the high temperature born by the steel flue 302 has certain limitation, the flue gas temperature of the kiln has to be controlled within the safe bearing range of the steel flue 302, the cooling water coil 4 exchanges heat with the high-temperature flue gas in the brick flue 301 and the steel flue 302, the flue gas temperature can be quickly reduced, the flue gas temperature passing through the steel flue 302 is ensured within the safe bearing range, while the prior art imports air into the flue 3 to reduce the flue gas temperature, but the air comprises nitrogen and oxygen, the nitrogen and the oxygen in the high-temperature flue gas can react to generate nitrogen oxide, while the cooling water coil 4 of the invention uses water as a medium to, the nitrogen in the air can be prevented from reacting in high-temperature flue gas to produce nitrogen oxides, and partial nitrogen oxides can be reduced by the method.

Thirdly, controlling the proportion of oxygen and natural gas introduced into the liquid crystal glass kiln 1, wherein the oxygen: the natural gas is 2.1-2.4:1

Chemical equation for combustion and nitric oxide generation from methane, the major component of natural gas:

CH₄+2O₂＝CO₂+2H₂chemical equation for combustion of natural gas

O₂+N₂Chemical equation for 2NO nitrogen oxide

I.e. the combustion volume ratio of complete reaction of oxygen and natural gas is 2: 1, because the TFT-LCD liquid crystal glass kiln is an oxygen-enriched combustion process, the actual combustion volume ratio is more than 2, and the selection of the oxygen-enriched amount which is as low as possible is beneficial to reducing the generation of nitrogen oxides according to the chemical equation of the generation of the nitrogen oxides, the volume ratio of the combustion of the oxygen and the natural gas selected in the example is 2.1-2.4:1, preferably 2.2: 1, not only meeting the stable production requirement of the process, but also achieving the optimal process state of controlling the nitrogen oxide.

As shown in fig. 1 and 3, the fuel or cooling gas control of the burning guns 2 in the invention is controlled by a combustion control system, and the specific system comprises a plurality of pairs of burning guns 2 which are arranged on two sides of a liquid crystal glass kiln 1 and have consistent structures, and a first pair of burning guns 201, a second pair of burning guns 202, a third pair of burning guns 203 and a fourth pair of burning guns 204 are respectively arranged along the direction far away from a flue; each burning gun of each pair of burning guns 2 is communicated with a natural gas pipeline 5, an oxygen pipeline 6 and a purified compressed air pipeline 7, wherein a natural gas control valve is arranged on the natural gas pipeline 5, an oxygen control valve is arranged on the oxygen pipeline 6, and a purified compressed air valve is arranged on the purified compressed air pipeline 7; the natural gas control valve, the oxygen control valve and the purification compressed air valve on each burning gun of each pair of burning guns 2 are all connected with the kiln combustion control system 8 to form a control loop, and the kiln combustion control system 8 independently controls the adjustment of the natural gas control valve, the oxygen control valve and the purification compressed air valve of each burning gun of the pair of burning guns; the plurality of burning guns 2 correspond to the control loops of the plurality of kiln burning control systems 8. In the invention, the burning guns 2 are controlled by the control system to meet the burning requirements of the liquid crystal glass kiln 1 at different periods, when the kiln normally produces the excessive fire, the kiln burning control system 8 corresponding to the fourth pair of burning guns 204 is adjusted to control the natural gas control valve in the fourth pair of burning guns 204 to be closed, the purification compressed air valve to be closed and the oxygen control valve to be opened, so that the function of cooling the fourth burning gun 204 by oxygen is realized, namely, the original working procedure of the natural gas burning of the burning guns 204 is changed into the working procedure that the burning system only supplies oxygen to the burning guns 204 and does not supply natural gas and the purification compressed air with cooling protection to the burning guns 204 by debugging the control procedure of the kiln burning system 8, and the function of replacing and purifying the compressed air by oxygen is realized. Meanwhile, the first pair of burning guns 201 is controlled to be filled with oxygen and natural gas; the kiln combustion control system 8 corresponding to the first pair of burning guns 201 controls the first pair of burning guns to purify and compress the air valve to close, the oxygen control valve to open and the natural gas control valve to open; and similarly, controlling the second pair of burning guns to be filled with oxygen and natural gas, and controlling the third pair of burning guns to be filled with oxygen and natural gas. And corresponding flow rates can be simultaneously controlled when the corresponding control valves are controlled.

By adopting the method for controlling the nitric oxide in the TFT-LCD liquid crystal glass kiln, the nitrogen entering the kiln is reduced by a plurality of methods through a method of reducing the nitrogen brought into the kiln by natural gas, a method of changing material media of cooling gas of the fourth pair of burning guns 204 in the kiln or a method of removing the fourth pair of burning guns 204; and then, by using the method of replacing air with water as the method for reducing the temperature of the flue gas and controlling the ratio of natural gas to oxygen, the generation of nitrogen oxide by mixing high-temperature flue gas and air and the reduction of the concentration of oxygen for generating the nitrogen oxide can be avoided, the material condition of generating the nitrogen oxide in the flue of the kiln is isolated or weakened, the generation of the nitrogen oxide can be greatly reduced, and even the national environmental protection emission standard to be implemented is met.

The method for controlling the nitrogen oxide in the kiln can meet the new national environmental protection emission standard without carrying out large technical transformation on the kiln and accessory equipment, can save a large amount of equipment investment related to environmental protection treatment, can reduce the emission of the nitrogen oxide particularly for the established production line through process adjustment and a small amount of equipment transformation, can meet the requirement of environmental protection emission while the service life of the residual equipment can be continued to produce, and saves fixed investment cost.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.