CN114538751B - Nitrogen-free gas glass kiln oxygen+CO 2 Method, system and device for circulating combustion - Google Patents

Abstract

The invention relates to a nitrogen-free gas glass kiln oxygen+CO ₂ A circulating combustion system and method. CO in the circulating flue gas of the oxygen and glass kiln ₂ Is prepared into oxygen-enriched gas serving as combustion improver for oxygen-enriched combustion of a glass kiln, and the nitrogen-free gas glass kiln is oxygen+CO ₂ The circulating combustion system has: an oxygen preparation device for preparing oxygen as an oxygen source; circulating flue gas CO ₂ Recovery device for recovering CO in tail gas of glass kiln ₂ As oxygen-enriched gas distribution; oxygen-enriched mixing device, oxygen prepared by oxygen preparation device and circulating flue gas CO ₂ CO recovered by recovery device ₂ The mixture is conveyed to an oxygen-enriched mixing device according to a required proportion, and is mixed in the oxygen-enriched mixing device to form oxygen-enriched gas serving as the combustion improver of the glass kiln; the raw material feeding device is used for providing raw materials used by the glass kiln to the glass kiln; and a glass kiln to which the oxygen-enriched gas formed by the oxygen-enriched mixing device is supplied.

Description

Nitrogen-free gas glass furnace oxygen + CO2 cycle combustion method, system and device

Technical field

The invention relates to a nitrogen _- free combustion technology. The main content refers to using oxygen + CO ₂ instead of air to support combustion in a glass kiln. It belongs to the technical field of glass kiln combustion. Oxygen is used as a combustion aid for methods, systems and devices for oxygen-enriched combustion in kilns.

Background technique

The glass industry is a large energy consumer. There are currently thousands of glass kilns in my country. The thermal efficiency and thermal energy utilization rate are relatively low. Moreover, the unit consumption of products is high, the cost is high, and the pollution is high. With the imbalance of global energy supply and the intensification of regional crises, , fuel prices continue to rise, and the cost of glass production is getting higher and higher. Therefore, research on energy conservation and emission reduction of glass melting furnaces is a topic of great strategic significance. The cost of fuel has increased from 30% to about 40% of the glass production cost, seriously affecting the economic benefits of the industry. Therefore, the glass industry has an urgent need for energy-saving technologies.

In the prior art, glass melting furnaces have always used air as the combustion medium. After analysis and research on the existing combustion system, it is believed that the use of air-assisted combustion is an important factor leading to high energy consumption, high pollution, and high greenhouse effect. Only 21% of oxygen in the air participates in combustion, and 78% of nitrogen not only does not participate in combustion, but a large amount of nitrogen is heated needlessly and discharged into the atmosphere at high temperatures, causing a large amount of heat loss. Nitrogen also reacts with oxygen at high temperatures to generate NOx. NOx gas discharged into the atmosphere can easily form acid rain and cause environmental pollution. It also carries a large amount of heat and is discharged into the atmosphere.

As the imbalance of global energy supply and the geopolitical crisis intensify, fuel prices continue to rise, and the cost of glass production is getting higher and higher. At the same time, the requirements for energy conservation and emission reduction of production companies are getting higher and higher. Historically, glass melting furnaces have always used air as the combustion medium. After analysis and research on the existing combustion system, it is believed that the use of air for combustion is an important factor leading to high energy consumption, high pollution, and high greenhouse effect. Only 21% of the oxygen in the air participates in combustion, and 78% of the nitrogen not only does not participate in combustion, but a large amount of nitrogen is heated needlessly and discharged into the atmosphere at high temperatures, causing a large amount of heat loss. Nitrogen also reacts with oxygen at high temperatures to generate NOx. NOx gas discharged into the atmosphere can easily form acid rain and cause environmental pollution. It also carries a large amount of heat and is discharged into the atmosphere. Therefore, it is urgent to adopt the present invention to achieve the energy-saving and emission-reducing effects of glass kilns.

In addition, the current domestic average unit energy consumption of float glass is 7800kJ/kg glass liquid, and the international average unit energy consumption is 5300-7250kJ/kg glass liquid. The energy consumption limit per unit product of new flat glass manufacturers is ≤6500kJ/kg glass liquid. Large gap.

At present, the nitrogen oxide content of hot flue gas of float glass is 1500-3000 mg/Nm ³ in China and 1200 mg/Nm ³ internationally, which puts great pressure on glass companies to meet emission standards. There is no need to delay the improvement of gas.

Contents of the invention

The nitrogen-free gas glass kiln oxygen + CO ₂ circulating combustion system involved in the present invention uses oxygen and CO ₂ in the circulating flue gas of the glass kiln to form rich oxygen as a combustion accelerator, and is used for oxygen-rich combustion in the glass kiln. The nitrogen-free The gas-fired glass kiln oxygen + CO ₂ circulating combustion system has: an oxygen preparation device for preparing oxygen as an oxygen source; a circulating flue gas CO ₂ recovery device to recover the CO ₂ in the glass furnace exhaust gas as an oxygen-enriched preparation. gas; the oxygen-enriched mixing device, the oxygen prepared by the oxygen preparation device and the CO ₂ recovered by the circulating flue gas CO ₂ recovery device are transported to the oxygen-enriched mixing device in the required proportion, and are mixed in the oxygen-enriched mixing device to form the glass as described Oxygen-rich gas as a kiln combustion aid; a raw material feeding device that provides raw materials used in the glass kiln to the glass kiln; a glass kiln that provides the oxygen-rich gas formed by the oxygen-rich mixing device to the glass kiln. Glass kiln, the oxygen-rich gas acts as a combustion accelerant and nitrogen-free fuel to carry out a combustion reaction in the glass kiln, releasing the heat required for the operation of the glass kiln.

The nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion system may also be such that the oxygen prepared by the oxygen preparation device is sent to the oxygen-enriched mixing device at a pressure of 0.05 to 0.2 MPa.

For example, in the nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion system according to a certain aspect of the invention, the oxygen produced by the oxygen preparation device may be oxygen with a purity greater than 90v%.

As for the nitrogen-free gas glass kiln oxygen + CO ₂ circulating combustion system described in a certain aspect of the invention, the gas distribution may also be a part of the purified circulating flue gas of the glass kiln.

As for the nitrogen-free gas glass kiln oxygen + CO ₂ cyclic combustion system described in a certain aspect of the invention, the CO ₂ may also be obtained after the glass kiln flue gas undergoes waste heat recovery, dust removal, and desulfurization.

In the nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion system described in a certain aspect of the invention, the oxygen-enriched gas concentration formed in the oxygen-enriched mixing device may be 23 to 35 v%.

As described in a certain aspect of the invention, the nitrogen-free gas glass kiln oxygen + CO ₂ circulating combustion system can also be that the raw material feeding device uses CO ₂ in the circulating flue gas to isolate the raw material feeding device to avoid the raw material feeding. generation of nitrogen oxides.

As for the nitrogen-free gas glass furnace oxygen + CO ₂ circulating combustion system according to a certain aspect of the invention, it may also be that the CO ₂ collected by the circulating flue gas CO ₂ recovery device is sent to the oxygen-enriched mixing device before it is sent to the oxygen-enriched mixing device. The pressure of the collected CO ₂ must be adjusted through a pressure adjustment device so that the gas pressure is suitable for transmission in the equipment.

As described in a certain aspect of the invention, the nitrogen-free gas glass kiln oxygen + CO ₂ circulating combustion system can also be that the glass kiln uses the CO ₂ in the circulating flue gas to control the glass kiln through air seals, air curtains, etc. Isolate the parts of the furnace that are prone to air leakage to avoid the generation of thermal nitrogen oxides.

The nitrogen-free gas glass kiln oxygen + CO ₂ cyclic combustion method involved in the present invention uses oxygen and CO ₂ in the circulating flue gas of the glass kiln to form a rich oxygen as a combustion accelerator, which is used for oxygen-rich combustion in the glass kiln. The nitrogen-free The oxygen + CO ₂ cyclic combustion method of a gas-fired glass kiln has the following steps: an oxygen preparation step to prepare oxygen as an oxygen source; a cyclic flue gas CO ₂ recovery step to recover CO ₂ in the glass furnace exhaust gas as an oxygen-enriched preparation. gas; the oxygen-enriched mixing step, the oxygen prepared by the oxygen preparation step and the CO ₂ recovered by the circulating flue gas CO ₂ recovery step are mixed in a required ratio to form an oxygen-enriched gas as a combustion aid for the glass furnace; raw material feed step of providing the raw materials used in the glass kiln to the glass kiln; an oxygen-rich combustion step in which the oxygen-rich gas formed in the oxygen-rich mixing step is provided to the glass kiln, and the oxygen-rich gas serves as a combustion support The agent and nitrogen-free fuel undergo a combustion reaction in the glass kiln to release the heat required for the operation of the glass kiln.

For example, in the nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion method described in a certain aspect of the invention, the oxygen prepared in the oxygen preparation step may be oxygen-enriched and mixed at a pressure of 0.05 to 0.2 MPa.

In the nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion method described in a certain aspect of the invention, the purity of the oxygen prepared in the oxygen preparation step may be greater than 90v%.

As for the nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion method described in a certain aspect of the invention, the gas distribution may also be part of the circulating flue gas of the purified glass furnace.

As described in a certain aspect of the invention, the nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion method can also be that the CO ₂ is obtained after waste heat recovery, dust removal, and desulfurization of the glass kiln flue gas.

In the nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion method described in a certain aspect of the invention, the oxygen-enriched gas formed in the oxygen-enriched mixing step may have an oxygen-enriched concentration of 23 to 35 v%.

As described in a certain aspect of the invention, the nitrogen-free gas glass kiln oxygen + CO ₂ cyclic combustion method can also be that, in the raw material feeding step, CO ₂ in the circulating flue gas is used to isolate the raw material feed, Avoid the generation of raw material nitrogen oxides.

As described in a certain aspect of the invention, the nitrogen-free gas glass kiln oxygen + CO ₂ cyclic combustion method can also be that the CO ₂ collected in the recycling flue gas CO ₂ recovery step is combined with the oxygen prepared in the oxygen preparation step. Before oxygen-enriched mixing, a pressure adjustment step is required to adjust the pressure of the collected CO ₂ so that the gas pressure is suitable for transmission in the equipment.

As described in a certain aspect of the invention, the nitrogen-free gas glass furnace oxygen + CO ₂ cyclic combustion method can also be used to use CO ₂ in the circulating flue gas to seal the parts of the glass kiln that are prone to air leakage through air seals, air curtains, etc. Isolate to avoid the generation of thermal nitrogen oxides.

[Effects of the invention]

According to the characteristics of gas radiation, only triatomic and polyatomic gases have radiation ability, and diatomic gases have almost no radiation ability. The higher the proportion of nitrogen without radiation ability, the smaller the blackness of the furnace gas, which affects the effect of the furnace gas on the glass liquid. Radiation power; after using the CO ₂ gas in the circulating flue gas to replace the nitrogen in the combustion air, at the same time, because of the oxygen-rich combustion, the water vapor and CO ₂ are increased. After the synergistic effect is superimposed, the blackness and coordination of the furnace gas are greatly improved. The radiation intensity of the material and molten glass increases the melting rate by more than 10%, and the melting quality is also improved accordingly, achieving a significant effect of energy saving and consumption reduction.

The optimization of the combustion environment makes the temperature distribution in the furnace more reasonable, effectively extending the service life of the kiln and boiler. The improvement of combustion conditions in the glass industry also shortens the heating time of the kiln, increases the output, reduces the defective rate, and increases the yield; at the same time, it reduces the need for fuel quality and makes the use of inferior fuel possible. Low-quality fuel is cheap and easy to source, reducing the overall energy cost of the product.

Oxygen-enriched combustion technology can not only increase the blackness of the flame, accelerate the combustion speed, increase the flame temperature, fully burn out the unburned materials carried in the flue gas, and reduce the blackness of the exhaust smoke. Combustion decomposition and formation of combustible and harmful gases are fully burned to reduce the generation of harmful gases. The exhaust temperature and smoke volume are significantly reduced, reducing thermal pollution and dust emissions. This invention changes terminal treatment to source treatment and achieves a fundamental breakthrough in ultra-low emission of nitrogen oxides.

Oxygen-enriched combustion technology has excellent performance in increasing production, saving energy and reducing emissions. It can reduce unit heat consumption and comprehensive energy consumption, increase production, reduce flue gas emissions, and achieve ultra-low NOx emissions.

In summary, the present invention has the following beneficial effects:

1. CO ₂ replaces nitrogen in the high-temperature combustion area of the kiln to avoid the formation of nitrogen oxides.

The combustion mechanism of conventional air-assisted combustion is: CmHn+O ₂ +N ₂ →CO ₂ +H ₂ O+NOx.

The combustion mechanism of oxygen-enriched (CO ₂ +O ₂ ) combustion-assisted combustion in the present invention is: CmHn+O ₂ +CO ₂ →CO ₂ +H ₂ O.

2. According to the characteristics of gas radiation, only triatomic and polyatomic gases have radiation ability, and diatomic gases have almost no radiation ability. The higher the proportion of nitrogen without radiation ability, the smaller the blackness of the furnace gas, which affects the effect of the furnace gas on the glass. The radiation power of the liquid; after using CO ₂ gas to replace nitrogen, at the same time, due to oxygen-rich combustion, both water vapor and CO ₂ are increased. After the synergistic effect is superimposed, the blackness of the furnace gas and the radiation to the batch materials and glass liquid are greatly improved. Strength, the melting rate is increased by more than 10%, and the melting quality is also improved accordingly, achieving significant effects of energy saving and consumption reduction;

3. The optimization of the combustion environment makes the temperature distribution in the furnace more reasonable, effectively extending the service life of the kiln and boiler. The improvement of combustion conditions in the glass industry also shortens the heating time of the kiln, increases the output, reduces the defective rate, and increases the yield; at the same time, it reduces the need for fuel quality and makes the use of inferior fuel possible. Low-quality fuel is cheap and easy to procure, reducing the overall energy cost of the product;

4. Oxygen-enriched combustion technology can not only increase the blackness of the flame, accelerate the combustion speed, increase the flame temperature, fully burn out the unburned materials carried in the flue gas, and reduce the blackness of the exhaust smoke. Combustion decomposition and formation of combustible and harmful gases are fully burned to reduce the generation of harmful gases. The exhaust temperature and smoke volume are significantly reduced, reducing thermal pollution and dust emissions;

5. Oxygen-enriched combustion technology has excellent performance in increasing production, saving energy and reducing emissions. It can reduce unit heat consumption and comprehensive energy consumption, increase production, reduce flue gas emissions, and achieve ultra-low NOx emissions;

6. The implementation of oxygen-enriched combustion technology does not require changes to the kiln body structure. Only partial optimization and transformation of the raw material feeding system, combustion-supporting system, and circulating flue gas system are required.

Description of drawings

Figure 1 is the structural diagram of the nitrogen-free gas glass furnace oxygen + CO ₂ circulating combustion system.

Figure 2 is a flow chart of oxygen + CO ₂ cyclic combustion in a nitrogen-free gas glass furnace.

Label description:

1 oxygen preparation device, 2 circulating flue gas CO ₂ recovery device, 3 variable frequency blower, 4 oxygen-enriched mixer, 5 oxygen-enriched transportation pipeline, 6 raw material feeding optimization system, 7 glass kiln, 8 flue gas purification system, 9 chimney .

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are the embodiments of the present invention. Some embodiments of the invention are disclosed, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. Accordingly, the following detailed description of embodiments of the invention provided in the appended drawings is not intended to limit the scope of the claimed invention, but rather to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

With the deepening of research on energy-saving and consumption-reducing technologies for glass melting furnaces, considerable research has been done on energy-saving methods for glass melting furnaces such as developing energy-saving glass formulas, optimizing glass melting furnace structures, improving glass melting furnace control technology, strengthening glass melting furnace insulation and waste heat utilization, etc. Mature. In this context, in order to achieve further energy saving and consumption reduction in furnaces, oxygen-enriched combustion technology emerged as the times require. Especially in recent years, oxygen-rich combustion technology has developed rapidly and has become one of the most active research topics in the glass industry today.

Oxygen-enriched combustion means that the oxygen concentration in the oxidant used to support combustion is higher than the oxygen concentration in the air (its limit is pure oxygen). It can concentrate the oxygen concentration of the air from 20.9% to 26% to 30%, and at the same time gradually replace the remaining nitrogen with carbon dioxide in the flue gas. This kind of oxygen-rich air is very moderate and safe for combustion support in various kilns. . This oxygen-rich combustion technology not only increases the blackness of the flame, accelerates the combustion speed, and increases the flame temperature, but also because carbon dioxide replaces nitrogen, it improves the radiative heat transfer and convective heat transfer of the flame to the batch material or glass liquid, and the combustion efficiency is high. Reduce _NOx emissions. At the same time, it can reduce the amount of flue gas, reduce the heat loss of the flue gas, and achieve good energy saving and environmental protection effects.

The following is an introduction to the nitrogen-free gas glass furnace oxygen + CO ₂ circulating combustion system using oxygen-rich combustion technology. Referring to Figure 1, the structure of the nitrogen-free gas glass kiln oxygen + CO ₂ circulating combustion system is explained. Figure 1 is the structural diagram of the nitrogen-free gas glass furnace oxygen + CO ₂ circulating combustion system.

1 in Figure 1 is an oxygen preparation device. Specifically, the oxygen preparation methods used by mature and commonly used oxygen preparation devices include cryogenic method, pressure swing adsorption method, membrane separation method, etc.

1. Cryogenic method: The full name of cryogenic method is deep freezing air separation method, also known as low-temperature distillation method. The process is to first compress, cool and liquefy the air, and then use the difference in the boiling points of the oxygen and nitrogen components (the boiling point of oxygen is 90K and the boiling point of nitrogen is 77K under atmospheric pressure) to make the gas, Liquid contact, mass and heat exchange, high boiling point oxygen components continue to condense from the steam into liquid, low boiling point nitrogen components continue to transfer into the steam, so that the nitrogen content in the rising steam continues to increase, and The oxygen content in the downstream liquid is getting higher and higher, causing oxygen and nitrogen to separate.

2. Pressure swing adsorption method: The pressure swing adsorption method is also called the molecular sieve air separation method. The principle is that the molecular sieve selectively adsorbs oxygen and nitrogen components in the air to separate the air to obtain oxygen. When the air is pressurized and passes through the adsorption layer of the molecular sieve adsorption tower, nitrogen molecules are preferentially adsorbed, and oxygen molecules remain in the gas phase to become the finished oxygen. When the adsorption of nitrogen components in the adsorbent reaches saturation, the nitrogen molecules adsorbed on the surface of the adsorbent are desorbed by decompression or vacuuming and sent out of the boundary area, thereby restoring the adsorption capacity of the adsorbent.

3. Membrane separation method: The basic principle of membrane separation is to achieve gas separation based on the different transfer rates of each component in the air through the membrane driven by pressure. Some high molecular polymers are used to selectively permeate the activity of different gases, and appropriate high molecular polymers are used to make hollow fibers to separate various gases in the air and obtain the required gases.

Example 1:

For large kilns, cryogenic oxygen production + CO ₂ in the circulating flue gas of the glass kiln is used as a combustion accelerant for oxygen-rich combustion in the glass kiln. The process is specifically described as:

Using the oxygen preparation device 1 in Figure 1, the air is first compressed, cooled, and liquefied. The difference in boiling points of the oxygen and nitrogen components is used to bring the gas and liquid into contact on the distillation tray to perform mass and heat exchange. High boiling points The oxygen component continues to condense from the steam into liquid, and the low boiling point nitrogen component continues to transfer into the steam, so that the nitrogen content in the rising steam continues to increase, while the oxygen content in the downstream liquid becomes higher and higher, thus Separate oxygen and nitrogen to obtain oxygen with a purity of 99.6v% or more.

The circulating flue gas CO ₂ recovery device 2 in Figure 1 recovers kiln exhaust gas. The flue gas purification system 8 in Figure 1 includes a waste heat recovery system, a dust removal system, and a desulfurization system. After the flue gas generated by the glass kiln 7 passes through the flue gas purification system 8, part of the circulating flue gas is led out and enters the circulating flue gas CO ₂ recovery device 2, and the rest is vented through the chimney 9. The gas collected by the circulating flue gas CO ₂ recovery device 2 is mainly CO ₂ . In order to make the gas suitable for transmission in the system, the gas collected by the circulating flue gas CO ₂ recovery device 2 is mainly CO ₂ through a variable frequency blower 3 . Pressure adjustment.

The gas mainly CO 2 collected by the circulating flue gas CO ₂ recovery device ₂ is pressure-regulated by the variable frequency blower 3 and then sent to the oxygen-enriched mixer 4 in Figure 1 through the flow indicator controller FIC; as shown in Figure 1, the cryogenic The separated oxygen is metered and adjusted by the flow indicator controller FIC and then sent to the oxygen-enriched mixer 4 through the oxygen pipeline; the oxygen and CO ₂ in the circulating flue gas are mixed in the oxygen-enriched mixer 4 to form 23-35v% oxygen-enriched , the pressure is 0.05~0.2MPa, and is sent to the glass kiln combustion system after being transmitted through the oxygen-rich transportation pipeline 5.

The above-mentioned oxygen-enriched transportation pipeline 5 is equipped with oxygen-enriched flow measurement, temperature measurement, pressure measurement, and oxygen purity detector to display the flow, temperature, pressure, and oxygen purity of oxygen-enriched gas entering the glass furnace combustion system.

In the raw material feeding optimization system 6, raw materials such as silica sand, soda ash, dolomite, limestone, and thenardite in the glass kiln will entrain and absorb air when entering the glass kiln. The CO ₂ in the circulating flue gas is used to optimize the raw material feeding system. Carry out isolation and replacement to avoid the generation of raw material nitrogen oxides.

In the glass kiln 7, CO ₂ in the circulating flue gas is used to isolate the parts of the glass kiln that are prone to air leakage through air seals, air curtains and other methods to avoid the generation of thermal nitrogen oxides.

It should be noted that in the initial stage of operation of the glass kiln, air is used to assist combustion. After the flue gas is generated, the rich oxygen produced by mixing circulating flue gas and oxygen is used as a combustion accelerant to gradually replace the air combustion. After 5 to 10 hours, Cycle, the nitrogen in the flue gas is gradually replaced by CO ₂ into nitrogen-free flue gas, and oxygen-rich combustion enters normal operation; during the operation of multiple series of kilns, the nitrogen-free flue gas can interconnect and protect each other.

Example 2:

For small and medium-sized kilns, the pressure swing adsorption method is used to produce oxygen + CO ₂ in the circulating flue gas of the glass kiln is used as a combustion accelerant for oxygen-rich combustion in the glass kiln. The process is specifically described as:

When the oxygen preparation device 1 in Figure 1 uses the pressure swing adsorption method to produce oxygen, when the air is pressurized and passes through the adsorption layer of the molecular sieve adsorption tower, nitrogen molecules are preferentially adsorbed, and the oxygen molecules remain in the gas phase to become the finished oxygen. When the adsorption of nitrogen components in the adsorbent reaches saturation, the nitrogen molecules adsorbed on the surface of the adsorbent are desorbed by decompression or vacuuming and sent out of the boundary area to restore the adsorption capacity of the adsorbent. Thereby, oxygen and nitrogen are separated to obtain oxygen with a purity of 90-95v%.

The circulating flue gas CO ₂ recovery device 2 in Figure 1 recovers kiln exhaust gas. The flue gas purification system 8 in Figure 1 includes a waste heat recovery system, a dust removal system, and a desulfurization system. After the flue gas generated by the glass kiln 7 passes through the flue gas purification system 8, part of the circulating flue gas is led out and enters the circulating flue gas CO ₂ recovery device 2, and the rest is vented through the chimney 9. The gas collected by the circulating flue gas CO ₂ recovery device 2 is mainly CO ₂ . In order to make the gas suitable for transmission in the system, the gas collected by the circulating flue gas CO ₂ recovery device 2 is mainly CO ₂ through a variable frequency blower 3 . Pressure adjustment.

The gas mainly CO 2 collected by the circulating flue gas CO ₂ recovery device ₂ is pressure-regulated by the variable frequency blower 3 and then sent to the oxygen-enriched mixer 4 in Figure 1 through the flow indicator controller FIC; in addition, as shown in Figure 1, The oxygen produced by cryogenic separation is metered and adjusted by the flow indicator controller FIC and then sent to the oxygen-enriched mixer 4 through the oxygen pipeline; the oxygen and CO ₂ in the circulating flue gas are mixed in the oxygen-enriched mixer 4 to 23~35v% Oxygen-enriched, with a pressure of 0.05 to 0.2MPa, is transported through the oxygen-enriched transportation pipeline 5 and then sent to the glass kiln combustion system.

The above-mentioned oxygen-enriched transportation pipeline 5 is equipped with oxygen-enriched flow measurement, temperature measurement, pressure measurement, and oxygen purity detector to display the flow, temperature, pressure, and oxygen purity of oxygen-enriched gas entering the glass furnace combustion system.

In the raw material feeding optimization system 6, raw materials such as silica sand, soda ash, dolomite, limestone, and thenardite in the glass kiln will entrain and absorb air when entering the glass kiln. The CO ₂ in the circulating flue gas is used to optimize the raw material feeding system. Carry out isolation and replacement to avoid the generation of raw material nitrogen oxides.

In the glass kiln 7, CO ₂ in the circulating flue gas is used to isolate the parts of the glass kiln that are prone to air leakage through air seals, air curtains and other methods to avoid the generation of thermal nitrogen oxides.

It should be noted that in the initial stage of operation of the glass kiln, air is used to assist combustion. After the flue gas is generated, the rich oxygen produced by mixing circulating flue gas and oxygen is used as a combustion accelerant to gradually replace the air combustion. After 5 to 10 hours, Cycle, the nitrogen in the flue gas is gradually replaced by CO ₂ into nitrogen-free flue gas, and oxygen-rich combustion enters normal operation; during the operation of multiple series of kilns, the nitrogen-free flue gas can interconnect and protect each other.

Example 3:

For small and medium-sized kilns, the membrane separation method is used to produce oxygen + CO ₂ in the circulating flue gas of the glass kiln is used as a combustion accelerant for oxygen-rich combustion in the glass kiln. The process is specifically described as:

When the oxygen production device 1 in Figure 1 uses a membrane separation method to produce oxygen, when the air is pressurized, it is made into hollow fibers by combining high molecular polymers to separate oxygen. Thus, oxygen with a purity of 93 to 99.5 v% is obtained.

The circulating flue gas CO ₂ recovery device 2 in Figure 1 recovers kiln exhaust gas. The flue gas purification system 8 in Figure 1 includes a waste heat recovery system, a dust removal system, and a desulfurization system. After the flue gas generated by the glass kiln 7 passes through the flue gas purification system 8, part of the circulating flue gas is led out and enters the circulating flue gas CO ₂ recovery device 2, and the rest is vented through the chimney 9. The gas collected by the circulating flue gas CO ₂ recovery device 2 is mainly CO ₂ . In order to make the gas suitable for transmission in the system, the gas collected by the circulating flue gas CO ₂ recovery device 2 is mainly CO ₂ through a variable frequency blower 3 . Pressure adjustment.

The gas mainly CO 2 collected by the circulating flue gas CO ₂ recovery device ₂ is pressure-regulated by the variable frequency blower 3 and then sent to the oxygen-enriched mixer 4 in Figure 1 through the flow indicator controller FIC; in addition, as shown in Figure 1, The oxygen produced by cryogenic separation is metered and adjusted by the flow indicator controller FIC and then sent to the oxygen-enriched mixer 4 through the oxygen pipeline; the oxygen and CO ₂ in the circulating flue gas are mixed in the oxygen-enriched mixer 4 to 23~35v% Oxygen-enriched, with a pressure of 0.05 to 0.2MPa, is transported through the oxygen-enriched transportation pipeline 5 and then sent to the glass kiln combustion system.

The above-mentioned oxygen-enriched transportation pipeline 5 is equipped with oxygen-enriched flow measurement, temperature measurement, pressure measurement, and oxygen purity detector to display the flow, temperature, pressure, and oxygen purity of oxygen-enriched gas entering the glass furnace combustion system.

In the raw material feeding optimization system 6, raw materials such as silica sand, soda ash, dolomite, limestone, and thenardite in the glass kiln will entrain and absorb air when entering the glass kiln. The CO ₂ in the circulating flue gas is used to optimize the raw material feeding system. Carry out isolation and replacement to avoid the generation of raw material nitrogen oxides.

In the glass kiln 7, CO ₂ in the circulating flue gas is used to isolate the parts of the glass kiln that are prone to air leakage through air seals, air curtains and other methods to avoid the generation of thermal nitrogen oxides.

It should be noted that in the initial stage of operation of the glass kiln, air is used to assist combustion. After the flue gas is generated, the rich oxygen produced by mixing circulating flue gas and oxygen is used as a combustion accelerant to gradually replace the air combustion. After 5 to 10 hours, Cycle, the nitrogen in the flue gas is gradually replaced by CO ₂ into nitrogen-free flue gas, and oxygen-rich combustion enters normal operation; during the operation of multiple series of kilns, the nitrogen-free flue gas can interconnect and protect each other.

In addition, the nitrogen-free gas glass kiln oxygen + CO ₂ cyclic combustion method involved in the present invention uses oxygen and CO ₂ in the circulating flue gas of the glass kiln to form rich oxygen as a combustion accelerant, which is used for oxygen-rich combustion in the glass kiln, such as As shown in Figure 2, this method has the following steps:

Oxygen preparation step: prepare oxygen as an oxygen source.

The circulating flue gas CO ₂ recovery step recovers the CO ₂ in the glass furnace exhaust gas as oxygen-rich gas distribution. The kiln exhaust gas is recovered using the circulating flue gas CO ₂ recovery device 2 as shown in Figure 1 . The flue gas purification system 8 includes a waste heat recovery system, a dust removal system, and a desulfurization system. After the flue gas generated by the glass kiln 7 passes through the flue gas purification system 8, part of the circulating flue gas is led out and enters the circulating flue gas CO ₂ recovery device 2, and the rest is vented through the chimney 9. The gas collected by the circulating flue gas CO ₂ recovery device 2 is mainly CO ₂ . In order to make the gas suitable for transmission in the system, the gas collected by the circulating flue gas CO ₂ recovery device 2 is mainly CO ₂ through a variable frequency blower 3 . Pressure adjustment.

In the oxygen-enriched mixing step, the oxygen prepared in the oxygen preparation step and the _CO2 recovered in the circulating flue gas _CO2 recovery step are mixed in a required ratio to form an oxygen-enriched gas that serves as a combustion accelerant for the glass kiln. The gas mainly CO 2 collected by the circulating flue gas CO ₂ recovery device ₂ is pressure-regulated by the variable frequency blower 3 and then sent to the oxygen-enriched mixer 4 in Figure 1 through the flow indicator controller FIC; in addition, as shown in Figure 1, The oxygen produced by cryogenic separation is metered and adjusted by the flow indicator controller FIC and then sent to the oxygen-enriched mixer 4 through the oxygen pipeline; the oxygen and CO ₂ in the circulating flue gas are mixed in the oxygen-enriched mixer 4 to 23~35v% Oxygen-enriched, with a pressure of 0.05 to 0.2MPa, is transported through the oxygen-enriched transportation pipeline 5 and then sent to the glass kiln combustion system.

The above-mentioned oxygen-enriched transportation pipeline 5 is equipped with oxygen-enriched flow measurement, temperature measurement, pressure measurement, and oxygen purity detectors to display the flow, temperature, pressure, and oxygen purity of oxygen-enriched gas entering the glass furnace combustion system.

In the raw material feeding step, raw materials used in the glass kiln are provided to the glass kiln. In the raw material feeding optimization system 6, raw materials such as silica sand, soda ash, dolomite, limestone, and thenardite in the glass kiln will entrain and absorb air when entering the glass kiln. The CO ₂ in the circulating flue gas is used to optimize the raw material feeding system. Carry out isolation and replacement to avoid the generation of raw material nitrogen oxides.

In the glass kiln 7, CO ₂ in the circulating flue gas is used to isolate the parts of the glass kiln that are prone to air leakage through air seals, air curtains and other methods to avoid the generation of thermal nitrogen oxides.

In the oxygen-rich combustion step, the oxygen-rich gas formed in the oxygen-rich mixing step is provided to the glass kiln, and the oxygen-rich gas is used as a combustion accelerant to perform a combustion reaction with nitrogen-free fuel in the glass kiln, releasing all the oxygen-rich gas. Describe the heat required for the operation of the glass kiln. It should be noted that in the initial stage of operation of the glass kiln, air is used to assist combustion. After the flue gas is generated, the rich oxygen produced by mixing circulating flue gas and oxygen is used as a combustion accelerant to gradually replace the air combustion. After 5 to 10 hours, Cycle, the nitrogen in the flue gas is gradually replaced by CO ₂ into nitrogen-free flue gas, and oxygen-rich combustion enters normal operation; during the operation of multiple series of kilns, the nitrogen-free flue gas can interconnect and protect each other.

As mentioned above, the present invention has been described with reference to the above-described embodiments. However, the present invention is not limited to each of the above-described embodiments, and appropriate combinations or substitutions of the structures of the respective embodiments are also included in the scope of the present invention. In addition, modifications such as combinations of the embodiments or processing procedures or various design changes can be appropriately adapted based on knowledge in the field, and embodiments to which such modifications are added may also be included. within the scope of the present invention.

Claims (1)

1. A nitrogen-free gas glass furnace oxygen + CO ₂ cycle combustion method, characterized by: Oxygen and CO ₂ in the circulating flue gas of the glass kiln are used to prepare oxygen-enriched combustion as a combustion aid, which is used for oxygen-enriched combustion in glass kilns. The nitrogen-free gas glass furnace oxygen + CO ₂ cycle combustion method has the following steps: The oxygen preparation step prepares oxygen as an oxygen source; the purity of the oxygen prepared in the oxygen preparation step is greater than 90v% oxygen; The recycling flue gas CO ₂ recovery step recovers the CO ₂ in the glass kiln exhaust gas as oxygen-rich gas distribution; the CO ₂ is obtained after the glass kiln flue gas undergoes waste heat recovery, dust removal, and desulfurization. The gas distribution is part of the circulating flue gas from the purified glass kiln; In the oxygen-rich mixing step, the oxygen prepared in the oxygen preparation step and the CO ₂ recovered in the circulating flue gas CO ₂ recovery step are mixed in a required ratio to form an oxygen-rich gas as a combustion accelerant for the glass kiln; wherein, the oxygen The oxygen prepared in the preparation step is oxygen-enriched and mixed at a pressure of 0.05 to 0.2 MPa; the CO ₂ collected in the circulating flue gas CO ₂ recovery step needs to be pressure adjusted before being oxygen-enriched and mixed with the oxygen prepared in the oxygen preparation step. Step: adjust the pressure of the collected CO ₂ so that the gas pressure is suitable for transmission in the equipment; the oxygen-enriched gas formed in the oxygen-enriched mixing step has an oxygen-enriched concentration of 23 to 35 v%; In the raw material feeding step, the raw materials used in the glass kiln are provided to the glass kiln; in the raw material feeding step, the CO ₂ in the circulating flue gas is used to isolate the raw material feed to avoid raw material nitrogen oxidation. the production of things; In the oxygen-rich combustion step, the oxygen-rich gas formed in the oxygen-rich mixing step is provided to the glass kiln, and the oxygen-rich gas is used as a combustion accelerant to perform a combustion reaction with nitrogen-free fuel in the glass kiln, releasing all the oxygen-rich gas. Describe the heat required for the operation of the glass kiln; use the CO ₂ in the circulating flue gas to isolate the parts of the glass kiln that are prone to air leakage through air seals and air curtains to avoid the generation of thermal nitrogen oxides; In the initial stage of operation of the glass kiln, air is used to assist combustion. After the flue gas is generated, the rich oxygen produced by mixing circulating flue gas and oxygen is used as a combustion accelerant to gradually replace the air combustion. After 5 to 10 hours of circulation, the flue gas contains The nitrogen is gradually replaced by CO ₂ into nitrogen-free flue gas, and oxygen-rich combustion enters normal operation; during the operation of multiple series of kilns, the nitrogen-free flue gas can be interconnected and protect each other.