Glass furnace heat storage combustion system and method for achieving low nitrogen oxide emissions

Abstract

The present invention discloses a glass furnace regenerative combustion system and a method for achieving low nitrogen oxide emissions. The system relates to a treatment device for reducing NOx emissions during regenerative combustion in a glass furnace. The system comprises a glass melting pool, a high-temperature regenerative chamber, and a four-way reversing valve. Two high-temperature regenerative chambers are symmetrically arranged on either side of the glass melting pool. The high-temperature regenerative chambers are provided with a first regenerative body and a second regenerative body from top to bottom. A second regenerative chamber is formed in the space below the second regenerative body. The second regenerative chambers of the two high-temperature regenerative chambers are connected to the four-way reversing valve via a second channel. The four-way reversing valve is also connected to a combustion-supporting blower and a chimney. The combustion-supporting blower and the chimney are respectively connected to the two high-temperature regenerative chambers through timed reversal of the four-way reversing valve to establish airflow channels in rotation. The present invention solves the problems of high investment, large equipment footprint, high operating costs, and high labor costs in current glass furnace nitrogen reduction systems, while achieving a lower NOx emission concentration.

Description

Technical Field

[0001] The present invention relates to a treatment device for reducing NOx emissions during thermal storage combustion in a glass furnace, and in particular to a thermal storage combustion system for a glass furnace and a method for achieving low nitrogen oxide emissions. Background Art

[0002] The glass industry holds an important position in my country's building materials production and is also one of the key industries for industrial pollution control. During the glass production process, since the melting temperature of raw materials is around 1500°C, the high-temperature zone generated by fuel combustion is relatively concentrated, resulting in the generation of large amounts of thermal nitrogen oxides in the glass melting furnace. At the same time, the flue gas temperature at the outlet of the glass melting furnace remains at around 1000°C. Currently, glass companies widely use high-temperature thermal storage combustion technology to fully recover the waste heat of the flue gas. High-temperature thermal storage combustion is based on a thermal storage body. High-temperature flue gas and combustion air alternately flow through the thermal storage body. Through reciprocating circulation, the physical sensible heat of the high-temperature flue gas is transferred to the combustion air. The combustion air is heated to around 800-1000°C before entering the kiln, which can effectively improve the utilization rate of flue gas waste heat and increase the thermal efficiency of the kiln.

[0003] NOx generation from glass production is currently not well controlled. Taking flat glass production as an example, untreated large-scale domestic glass kilns currently emit nitrogen oxides at levels between 1,200 and 3,000 mg / Nm³, far exceeding the levels of other industries. Large quantities of nitrogen oxides are emitted annually, causing severe environmental pollution such as acid rain, photochemical smog, ozone layer depletion, and haze. The latest "Flat Glass Industry Air Pollutant Emission Standard" sets a nitrogen oxide emission standard of 700 mg / Nm³. To meet these standards, most companies use the more mature selective catalytic denitrification (SCR) technology to reduce NOx concentrations in flue gas. SCR technology operates within an effective reaction temperature range of approximately 320°C to 450°C. The most commonly used reducing agent is ammonia, typically sourced from aqueous or liquid ammonia, requiring appropriate ammonia injection systems and equipment. SCR technology also presents challenges with catalyst poisoning and alkaline dust in the flue gas clogging and reducing catalytic efficiency. Companies need to equip themselves with large-scale, high-temperature dust removal equipment to mitigate these issues. In addition to the high catalyst cost, the SCR technology system also occupies a large area and requires high investment in auxiliary equipment. During its normal operation, it must continuously purchase reducing agents, which also increases the maintenance costs of related equipment and additional human resource costs. These costs have brought a huge economic burden to glass production companies, seriously affecting their market competitiveness and survival ability.

[0004] The inventor previously applied for a patent for a technology and system for directly degrading NOx during combustion in industrial furnaces. This technology has the advantages of low initial investment, easy maintenance, and no increased labor costs, but it did not propose specific solutions specifically for the process structure of glass furnaces. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention provides a glass kiln heat storage combustion system and a method for achieving low nitrogen oxide emissions, which solve the problems of high investment, large equipment footprint, high operating expenses and labor costs in the current glass kiln nitrogen reduction system, while achieving a lower NOx emission concentration.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A glass furnace heat storage combustion system, comprising:

[0008] A glass melting pool, on the side wall of which a first fuel spray gun and a second fuel spray gun are symmetrically mounted;

[0009] High-temperature regenerators, wherein the two high-temperature regenerators are symmetrically arranged on both sides of the glass melting pool, and the high-temperature regenerators are provided with a first regenerator and a second regenerator from top to bottom, wherein the heat storage temperature of the first regenerator is higher than the heat storage temperature of the second regenerator; a first heat storage cavity is formed in the space above the first regenerator, and the first heat storage cavities of the two high-temperature regenerators are connected to the glass melting pool through a first channel;

[0010] A four-way reversing valve is provided, wherein a second heat storage chamber is formed in the space below the second heat storage body, and the second heat storage chambers of the two high-temperature heat storage chambers are connected to the four-way reversing valve through a second channel. The four-way reversing valve is also connected to a combustion-supporting fan and a chimney. Specifically, through the timed reversal of the four-way reversing valve, the combustion-supporting fan and the chimney respectively establish airflow channels with the two high-temperature heat storage chambers in rotation.

[0011] As described above, the glass kiln heat storage combustion system, further, the first heat storage body uses zirconium oxide as the base heat storage material, mixed with one or more of the components such as cerium oxide, yttrium oxide, dysprosium oxide, samarium oxide, barium oxide, copper oxide, magnesium oxide, aluminum oxide, etc., and forms the heat storage body by sintering and forming structural parts, surface coating and other processes.

[0012] As described above, the glass kiln heat storage combustion system, further, the shape of the first heat storage body is a spherical, honeycomb, sheet, tubular, square with holes and other structures, which is formed by stacking and installing to form the heat storage body main structure, and regular or irregular flue gas channels are formed in the heat storage body.

[0013] The glass furnace heat storage combustion system as described above, further, the second heat storage body is constructed using ordinary alumina checker bricks.

[0014] A method for achieving low nitrogen oxide emissions in regenerative combustion, which is used in the regenerative combustion system of a glass furnace as described above, comprises:

[0015] The fuel injected by the second fuel spray gun mixes with the high-temperature air entering the glass melting pool from the high-temperature regenerator on the right and burns. The heat generated by the combustion melts the glass raw materials in the glass melting pool into glass liquid.

[0016] As combustion proceeds, flue gas carrying nitrogen oxides enters the left high-temperature regenerator;

[0017] The flue gas with a temperature exceeding a first set temperature first enters the flue gas channel of the left first heat storage body, heating the left first heat storage body, and the temperature of the left first heat storage body quickly rises to above a second set temperature;

[0018] In a high-temperature, low-oxygen environment, oxygen vacancies formed on the surface of the oxide material of the thermal storage body absorb a large amount of NO in the flue gas. After adsorption, the oxygen vacancies quickly break the NO bond through electron competition, and directly decompose NO into N2 and O2 and release them. The nitrogen oxides in the flue gas drop below the set standard, and at the same time, the flue gas temperature drops below the third set temperature;

[0019] The flue gas that has undergone nitrogen reduction treatment enters the second heat storage body on the left to continue releasing heat. After transferring the heat to the second heat storage body on the left, it enters the second channel connected by the four-way reversing valve and the chimney and is discharged.

[0020] As described above, the method for achieving low nitrogen oxide emissions in thermal storage combustion, further, the combustion-supporting air sent in by the combustion-supporting fan enters the first channel connected to the four-way reversing valves and the high-temperature thermal storage chamber on the right side, and after being continuously heated by the second thermal storage body on the right side and the first thermal storage body on the right side, is sent into the glass melt 4 to be mixed with the fuel for combustion.

[0021] The method for achieving low nitrogen oxide emissions in thermal storage combustion as described above further comprises: after the temperatures of the right first thermal storage body and the right second thermal storage body drop, first closing the second fuel spray gun, and then switching the four-way reversing valve to connect the combustion-supporting fan to the left high-temperature thermal storage chamber, and the right high-temperature thermal storage chamber to the chimney;

[0022] After the combustion air sent in by the combustion-supporting fan enters the glass melting pool through continuous heating of the second heat storage body on the left and the first heat storage body on the left, the first fuel spray gun is turned on to spray fuel to burn in the high-temperature air to provide heat. The high-temperature flue gas after combustion enters the high-temperature heat storage chamber on the right, and the cycle is repeated.

[0023] Compared with the prior art, the present invention has the following beneficial effects: the present invention has the characteristics of one-time investment, easy installation and low maintenance, no additional equipment and new site, and at the same time does not change the existing structure and process flow of the glass kiln, greatly reducing the high investment and operation and maintenance costs of nitrogen oxide emission reduction in glass enterprises, and can also achieve lower NOx emission requirements. It can be well matched with glass melting furnaces, non-ferrous metallurgical smelting furnaces, steel industry regenerative furnaces and other occasions that adopt high-temperature heat storage combustion technology to reduce NOx emission concentration in high-temperature production, thereby contributing to the enterprise's pollutant emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 Schematic diagram of the high-temperature regenerative technology for achieving low NOx emissions in thermal storage combustion in glass furnaces.

[0026] List of reference numerals:

[0027] 1 High-temperature heat storage chamber (one); 2 High-temperature heat storage body (one); 3 Fuel spray gun (one); 4 Glass melting pool; 5 Fuel spray gun (two); 6 High-temperature heat storage body (two); 7 High-temperature heat storage chamber (two); 8 Medium- and low-temperature heat storage body (two); 9 Combustion-supporting fan; 10 Chimney; 11 Four-way reversing valve; 12 Medium- and low-temperature heat storage body (one). DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] Example:

[0030] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0032] In the description of the present invention, "plurality" means at least two, such as two or three, unless otherwise specifically defined. Furthermore, unless otherwise specified or defined, the terms "mounted," "connected," and "connected" should be understood broadly, meaning, for example, fixed, removable, or integral; mechanical or electrical; direct or indirect through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention.

[0033] The present invention provides a glass kiln heat storage combustion system and a method for achieving low nitrogen oxide emissions, which solves the problems of high investment, large equipment footprint, high operating expenses and labor costs in current glass kiln nitrogen reduction systems, while achieving lower NOx emission concentrations.

[0034] exist Figure 1In the glass kiln heat storage combustion system shown, fuel spray gun (1) 3 and fuel spray gun (2) 5 are installed on the side wall of the glass melting pool 4, and the spray gun 3 and the spray gun 5 are arranged opposite to each other and operate alternately at intervals; the high-temperature heat storage chamber (1) 1 and the high-temperature heat storage chamber (2) 7 are connected to the glass melting pool 4 through the flue gas channel above the fuel spray gun; high-temperature heat storage bodies 2 and 6 are installed at one end of the high-temperature heat storage chambers 1 and 7 near the flue gas outlet of the melting pool; ordinary medium and low-temperature heat storage bodies 8 and 12 are installed below the high-temperature heat storage bodies; the bottom channel of the heat storage chamber is connected to the four-way reversing valve 11 through a pipeline, and the four-way reversing valve is simultaneously connected to the combustion-supporting fan 9 and the chimney 10. Through the timed reversing of the four-way reversing valve, the combustion-supporting fan 9 and the chimney 10 respectively establish airflow channels with the two high-temperature heat storage chambers in rotation. The high-temperature regenerator uses zirconium oxide as the base material, mixed with one or more of the following components: cerium oxide, yttrium oxide, dysprosium oxide, samarium oxide, barium oxide, copper oxide, magnesium oxide, and aluminum oxide. The regenerator is formed through sintering, forming structural components, and then surface coating. In a high-temperature, low-oxygen environment, oxygen vacancies formed on the surface of the oxide material adsorb NO from the flue gas. The oxygen vacancies rapidly break the NO bonds, and NO in the flue gas is directly decomposed into N2 and O2 and released. This achieves direct degradation of nitrogen oxides in the high-temperature zone, reducing NOx concentrations in the flue gas. The regenerator material can be shaped in various shapes, including spheres, honeycombs, sheets, tubes, and square structures with holes. These are stacked and assembled to form the main structure, creating regular or irregular flue gas channels within the main structure. The medium- and low-temperature regenerators are constructed using standard alumina checker bricks.

[0035] The specific working process of this embodiment is as follows: the fuel injected by the fuel injection gun 5 mixes with the high-temperature air entering the glass furnace from the high-temperature regenerator 7 and burns. The heat generated by the combustion melts the glass raw materials in the molten pool into molten glass. Since the temperature in the glass molten pool exceeds 1500°C, according to the Zel'dovich mechanism, the concentration of thermal NOx at this time increases exponentially with temperature, and a large amount of nitrogen oxides is generated in the flue gas. As the combustion proceeds, the high-temperature flue gas carrying nitrogen oxides enters the high-temperature heat storage chamber 1. The flue gas with a temperature exceeding 1000°C first enters the flue gas channel in the high-temperature heat storage body 2, heating the high-temperature heat storage body 2, and the temperature of the high-temperature heat storage body rapidly rises to above 800°C; in the high-temperature, low-oxygen environment, the oxygen vacancies formed on the surface of the oxide material of the heat storage body adsorb a large amount of NO in the flue gas. After adsorption, the oxygen vacancies quickly break the NO bond through electron competition, and directly decompose NO into N2 and O2 and release them. The nitrogen oxides in the flue gas drop to below 700mg / Nm3, and the flue gas temperature drops to below 800°C; the flue gas that has undergone nitrogen reduction treatment enters the medium and low-temperature heat storage body 12 to continue to release heat. After transferring the heat to the medium and low-temperature heat storage body, it enters the exhaust channel connected by the four-way reversing valve 11 and the chimney 10 for discharge. At this time, the combustion-supporting air sent in by the combustion-supporting blower 9 enters the air channel connected to the four-way reversing valve 11 and the high-temperature heat storage chamber (2) 7. After being continuously heated by the medium and low-temperature heat storage body 8 and the high-temperature heat storage body 6 in the heat storage chamber, it is sent into the glass melting pool 4 to mix with the fuel for combustion.

[0036] After the temperature of the high-temperature heat storage body 6 and the medium- and low-temperature heat storage body 8 drops, the fuel spray gun 5 is first closed, and then the four-way reversing valve 11 is switched to connect the combustion-supporting fan 9 with the high-temperature heat storage chamber 1, and the high-temperature heat storage chamber 7 with the chimney 10; after the combustion-supporting air sent in by the combustion-supporting fan 9 enters the glass melting pool through continuous heating of the medium- and low-temperature heat storage body 12 and the high-temperature heat storage body 2, the fuel spray gun 3 is opened, and the fuel is sprayed to burn in the high-temperature air to provide heat. The high-temperature flue gas after combustion enters the high-temperature heat storage chamber 7, and the same process as the flue gas entering the high-temperature heat storage chamber 1 is repeated. This cycle is repeated to form high-temperature heat storage combustion in the glass melting pool, reduce the concentration of nitrogen oxides in the flue gas, and reduce the nitrogen oxide emissions of the glass kiln to meet the national emission standards.

[0037] Example 1:

[0038] Zirconia is used as the matrix to make high-temperature thermal storage materials, and the surface is coated with cerium oxide, barium oxide, and yttrium oxide materials in a ratio of 10%:20%:70%. The thermal storage material is placed in a temperature environment of 800-1100°C and is introduced into a mixed flue gas of O2 and CO2 containing a NO concentration of 1000ppm. After a period of material degradation, the outlet NO concentration dropped to 88ppm, and the NO degradation rate was above 90%, which fully met the current industry emission standards.

[0039] Compared with the existing technology, the present invention has the characteristics of one-time investment, easy installation and low maintenance, no additional equipment and new site required, and does not change the existing structure and process flow of the glass kiln, greatly reducing the high investment and operation and maintenance costs of nitrogen oxide emission reduction in glass enterprises, and can also achieve lower NOx emission requirements. It can be well used in glass melting furnaces, non-ferrous metallurgical smelting furnaces, steel industry heat storage furnaces and other occasions that adopt high-temperature heat storage combustion technology to reduce NOx emission concentration in high-temperature production and contribute to the enterprise's pollutant emission reduction.

[0040] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0041] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the essence of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A glass furnace heat storage combustion system, characterized in that: include: A glass melting pool, on the side wall of which a first fuel spray gun and a second fuel spray gun are symmetrically mounted; High-temperature heat storage chamber, two high-temperature heat storage chambers are symmetrically arranged on both sides of the glass melting pool, and the high-temperature heat storage chambers are provided with a first heat storage body and a second heat storage body from top to bottom, wherein the heat storage temperature of the first heat storage body is higher than the heat storage temperature of the second heat storage body, and the first heat storage body is used in a high-temperature and low-oxygen environment. The oxygen vacancies formed on the surface of the heat storage body oxide material adsorb a large amount of NO in the flue gas. After adsorption, the oxygen vacancies quickly break the NO bond through electron competition, and the NO is directly decomposed into N2 and O2 and released, and the nitrogen oxides in the flue gas are reduced to below the set standard The second heat storage body is used to absorb the heat of the flue gas that has been treated with nitrogen reduction. The first heat storage body uses zirconium oxide as the base heat storage material, mixed with one or more of cerium oxide, yttrium oxide, dysprosium oxide, samarium oxide, barium oxide, copper oxide, magnesium oxide and aluminum oxide components, and forms the heat storage body by sintering and forming structural parts and surface coating processes. The space above the first heat storage body forms a first heat storage cavity, and the first heat storage cavities of the two high-temperature heat storage chambers are connected to the glass melting pool through a first channel. The second heat storage body is constructed of ordinary alumina checker bricks. A four-way reversing valve is provided, wherein a second heat storage chamber is formed in the space below the second heat storage body, and the second heat storage chambers of the two high-temperature heat storage chambers are connected to the four-way reversing valve through a second channel. The four-way reversing valve is also connected to a combustion-supporting fan and a chimney. Specifically, through the timed reversal of the four-way reversing valve, the combustion-supporting fan and the chimney respectively establish airflow channels with the two high-temperature heat storage chambers in rotation.

2. The glass furnace thermal storage combustion system according to claim 1, characterized in that: The first heat storage body is in the shape of a sphere, honeycomb, sheet, tube, or square porous structure, which is formed by stacking and installing to form a heat storage body main structure, and a regular or irregular flue gas channel is formed in the heat storage body.

3. A method for achieving low nitrogen oxide emissions in thermal storage combustion, which is used in the thermal storage combustion system of a glass furnace according to any one of claims 1-2, characterized in that: include: The fuel injected by the second fuel spray gun mixes with the high-temperature air entering the glass melting pool from the high-temperature regenerator on the right and burns. The heat generated by the combustion melts the glass raw materials in the glass melting pool into molten glass. As combustion proceeds, flue gas carrying nitrogen oxides enters the left high-temperature regenerator; The flue gas with a temperature exceeding the first set temperature first enters the flue gas channel of the left first heat storage body, heating the left first heat storage body, and the temperature of the left first heat storage body quickly rises to above the second set temperature; In a high-temperature, low-oxygen environment, oxygen vacancies formed on the surface of the oxide material of the thermal storage body absorb a large amount of NO in the flue gas. After adsorption, the oxygen vacancies quickly break the NO bond through electron competition, and directly decompose NO into N2 and O2 and release them. The nitrogen oxides in the flue gas drop below the set standard, and at the same time, the flue gas temperature drops below the third set temperature; The flue gas that has undergone nitrogen reduction treatment enters the second heat storage body on the left to continue releasing heat. After transferring the heat to the second heat storage body on the left, it enters the second channel connected by the four-way reversing valve and the chimney and is discharged.

4. The method for achieving low nitrogen oxide emissions in thermal storage combustion according to claim 3, characterized in that: The combustion-supporting air sent in by the combustion-supporting fan enters the first channel connecting the four-way reversing valve and the high-temperature heat storage chamber on the right. After being continuously heated by the second heat storage body on the right and the first heat storage body on the right, it is sent into the glass melt and mixed with the fuel for combustion.

5. The method for achieving low nitrogen oxide emissions in thermal storage combustion according to claim 4, characterized in that: After the temperatures of the first and second heat storage bodies on the right side drop, the second fuel spray gun is closed first, and then the four-way reversing valve is switched to connect the combustion-supporting fan to the left high-temperature heat storage chamber, and the right high-temperature heat storage chamber to the chimney; After the combustion air sent in by the combustion-supporting fan enters the glass melting pool through continuous heating of the second heat storage body on the left and the first heat storage body on the left, the first fuel spray gun is turned on to spray fuel to burn in the high-temperature air to provide heat. The high-temperature flue gas after combustion enters the high-temperature heat storage chamber on the right, and the cycle is repeated.

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