Tin bath tail gas and ammonia gas SNCR (selective non-catalytic reduction) auxiliary denitration device
By introducing tin tank exhaust gas and ammonia gas SNCR assisted denitrification devices in the production of float glass, the problems of direct combustion emissions of tin tank exhaust and exceeding the standard of nitrogen oxides are solved, and the rational utilization of exhaust gas and safe reduction of nitrogen oxides are achieved, and energy waste and ammonia water use are reduced.
Patent Information
- Application Number
- CN202422660472.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2034-11-01
AI Technical Summary
In the prior art, direct combustion emissions of tin tank exhaust gas and nitrogen and hydrogen mixture lead to waste of energy, and denitrification devices are prone to problems such as nitrogen oxide exceeding the standard.
The tin tank exhaust gas and ammonia gas SNCR assisted denitrification device is used. By setting up heat storage chambers and liquid ammonia gasification devices on both sides of the kiln, the ammonia gas is introduced into the kiln combustion chamber in two channels, reacting with the nitrogen oxides in the flue gas, and secondary denitrification is carried out in combination with BATH exhaust gas to reduce nitrogen oxide emissions.
The rational use of tin tank exhaust gas is achieved, nitrogen oxide emissions and ammonia water use are reduced, safety and equipment stability are improved, and costs are reduced.
Smart Images
Figure CN223287875U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of float glass production equipment, in particular to a tin bath tail gas and ammonia SNCR auxiliary denitrification device. Background Art
[0002] In float glass production, the tin bath (BATH) is an essential thermal equipment, and the glass is formed in the BATH. A nitrogen-hydrogen mixture (of which hydrogen accounts for 5%-12%) is the bath's protective gas, and is continuously introduced to maintain a slightly positive pressure. The small amount of hydrogen in the nitrogen-hydrogen mixture acts as a reducing gas, capturing oxygen that seeps into the bath, thereby protecting the tin liquid from oxidation. The bath's tail gas (i.e., a nitrogen-hydrogen mixture, of which the hydrogen content accounts for approximately 4%-10%) is continuously discharged through the outlet curtain and the exhaust (VENTING) outlet, of which the nitrogen-hydrogen mixture discharged through the VENTING outlet accounts for approximately 50%.
[0003] Currently, the nitrogen-hydrogen mixture emitted through the venting outlet is directly combusted and then discharged, resulting in energy waste. Furthermore, most current denitrification systems use ammonia, which requires an ammonia pump and air to atomize for the most even spray distribution. This often results in excessive nitrogen oxide levels in the flue gas due to ammonia pump failure. Utility Model Content
[0004] The purpose of the utility model is to provide a tin bath tail gas and ammonia SNCR auxiliary denitrification device, which effectively solves the current problem that the nitrogen and hydrogen mixed gas discharged through the venting outlet is not utilized but directly burned and discharged.
[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:
[0006] A tin bath tail gas and ammonia SNCR assisted denitrification device comprises a tin bath, a kiln, a liquid ammonia tank and a liquid ammonia gasification device. An exhaust outlet is provided at the front end of the tin bath, a left regenerator is provided on the left side of the kiln, and a right regenerator is provided on the right side of the kiln. Flue gases from the left and right regenerators are collected through a flue gas collecting pipe and then transported to a desulfurization and denitrification device.
[0007] The exhaust outlet of the tin bath is communicated with the flue gas collecting pipe through a first pipe, and a certain distance is spaced between an end of the first pipe away from the flue gas collecting pipe and the exhaust outlet.
[0008] An adjustable baffle for maintaining the tin bath pressure stable is provided at one end of the first pipe away from the flue gas collecting pipe.
[0009] The outlet of the liquid ammonia tank is connected to the liquid ammonia gasification device, the gaseous ammonia outlet of the liquid ammonia gasification device is connected to the left heat storage chamber of the kiln through a second pipe, and the gaseous ammonia outlet of the liquid ammonia gasification device is connected to the right heat storage chamber of the kiln through a third pipe. Automatic shut-off valves are provided on the second pipe and the third pipe.
[0010] Furthermore, the distance between the end of the first pipe away from the flue gas collecting pipe and the exhaust outlet is 50 mm.
[0011] Furthermore, the end of the first pipe away from the flue gas collecting pipe is in a trumpet shape that expands outward.
[0012] Furthermore, the adjustable baffle is arranged at the trumpet-shaped port of the first pipe.
[0013] Furthermore, a through hole for accommodating the second pipe or the third pipe is provided on the wall of the left heat storage chamber and the right heat storage chamber, and the ends of the second pipe and the third pipe connected to the heat storage chamber are both in the through hole and 20 mm away from the inner end of the through hole.
[0014] Furthermore, the diameters of the second pipe and the third pipe are both 25 mm.
[0015] Compared with the prior art, the beneficial technical effects of the present invention are:
[0016] (1) The present invention introduces ammonia into the combustion chambers on both sides of the kiln in two ways through the above-mentioned device, and switches the direction asynchronously with the side firing of the kiln so that it reacts with nitrogen oxides in the flue gas to achieve preliminary denitrification of the flue gas; by introducing the BATH tail gas (nitrogen-hydrogen mixed gas) discharged through the exhaust outlet into the flue gas collecting pipe, the BATH tail gas reacts with the nitrogen oxides in the flue gas of preliminary denitrification to achieve secondary denitrification of the flue gas, thereby reducing the emission of nitrogen oxides, reducing the load of the desulfurization and denitrification device, reducing the amount of ammonia used, and reducing costs.
[0017] (2) The flue gas of the utility model enters the desulfurization and denitrification device after undergoing two denitrification processes, which is beneficial to reducing the amount of ammonia water used. It is even unnecessary to introduce ammonia water into the desulfurization and denitrification device, thereby helping to simultaneously solve the problem of excessive nitrogen oxide content in the flue gas due to ammonia water pump failure and the problem of unreasonable utilization of the nitrogen-hydrogen mixed gas discharged from the exhaust outlet.
[0018] (3) The utility model provides an adjustable baffle at the trumpet-shaped port of the first pipe, thereby facilitating stable tin bath pressure. Since the hydrogen content of the bath exhaust gas is less than 1% after entering the flue gas manifold, there is no risk of explosion. Therefore, while ensuring safety and stable tin bath pressure, the utility model fully and rationally utilizes the bath exhaust gas discharged from the exhaust outlet of the tin bath, thereby achieving the goal of energy conservation and consumption reduction. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic diagram of the connection structure of the present utility model.
[0020] Explanation of the reference numerals: tin bath - 1; kiln - 2; exhaust outlet - 3; left heat storage chamber - 4; right heat storage chamber - 5; flue gas collecting pipe - 6; desulfurization and denitrification device - 7; first pipeline - 8; trumpet-shaped port - 9; adjustable baffle - 10; second pipeline - 11; third pipeline - 12; automatic shut-off valve - 13. DETAILED DESCRIPTION
[0021] Example 1: A SNCR-assisted denitrification device for tin bath tail gas and ammonia, such as Figure 1 As shown, the system comprises a tin bath 1, a kiln 2, a liquid ammonia tank, and a liquid ammonia vaporizer. The liquid ammonia tank is located in the tank area, and its outlet is connected to the liquid ammonia vaporizer. A venting outlet 3 is located at the front end of the tin bath 1. A left regenerator 4 is located on the left side of the kiln 2, and a right regenerator 5 is located on the right side of the kiln 2. Heat is exchanged between the left and right regenerators 4 and 5 by a time difference. When the kiln 2 is firing in the left direction, flue gas exits the right regenerator 5, and combustion air enters the left regenerator 4. As the combustion air enters the regenerator, it is heated, cooling the regenerator. 15-20 minutes later, when firing in the right direction, flue gas exits the left regenerator 4, and combustion air enters the right regenerator 5, repeating the cycle. Flue gas from the left and right regenerators 4 and 5 is combined in a flue gas manifold 6 and transported to a desulfurization and denitrification unit 7.
[0022] The exhaust outlet 3 of the tin bath 1 is connected to the flue gas manifold 6 via a first conduit 8. The end of the first conduit 8, remote from the flue gas manifold 6, is not tightly connected to the exhaust outlet 3, leaving a 50mm gap between them. Because the bath exhaust gas discharged from the exhaust outlet 3 of the tin bath 1 enters the flue gas manifold 6 through the first conduit 8 due to the negative pressure generated by the denitrification duct fan, no additional power fan is required.
[0023] In this embodiment, in order to prevent the escape of BATH exhaust gas, the end of the first pipe 8 away from the flue gas collecting pipe 6 is specially designed to be in a trumpet shape that expands outward.
[0024] To maintain a stable pressure in the tin bath 1, an adjustable baffle 10 is provided at the trumpet-shaped end 9 of the first conduit 8. Because the adjustable baffle 10 is located close to the tin bath 1, it is easily adjustable by personnel working at the tin bath 1. Because the operating conditions are continuously stable, the position of the adjustable baffle 10 rarely needs to be adjusted again after a single adjustment.
[0025] The gaseous ammonia outlet of the liquid ammonia vaporizer is connected to the left regenerator 4 of kiln 2 via a second pipe 11. The gaseous ammonia outlet of the liquid ammonia vaporizer is connected to the right regenerator 5 of kiln 2 via a third pipe 12. Both the second and third pipes 11, 12 are equipped with automatic shut-off valves 13. The switching timing of the automatic shut-off valves 13 aligns with the timing of kiln 2's combustion reversal. When the gaseous ammonia from the liquid ammonia tank enters kiln 2, it does not participate in combustion but instead undergoes a selective, non-catalytic reaction with nitrogen oxides in the flue gas. Specifically, when kiln 2 is firing in the left direction, the automatic shut-off valve 13 on the third pipe 12 opens, while the automatic shut-off valve 13 on the second pipe 11 closes. When kiln 2 is firing in the right direction, the automatic shut-off valve 13 on the second pipe 11 opens, while the automatic shut-off valve 13 on the third pipe 12 closes. This allows the gaseous ammonia to selectively react with nitrogen oxides in the flue gas in a non-catalytic manner.
[0026] In this embodiment, the automatic shut-off valve 13 has a flow regulating function. Orifice flow meters are provided on the second pipeline 11 and the third pipeline 12 and are connected to the automatic shut-off valve 13 to provide a feedback signal for the automatic shut-off valve 13 .
[0027] In this embodiment, a through-hole for accommodating the second pipe 11 or the third pipe 12 is provided in the wall of each of the left and right regenerator chambers 4 and 5. The ends of the second and third pipes 11 and 12 connected to the regenerator chambers are located within the through-holes, approximately 20 mm from the inner ends of the through-holes. In this embodiment, the second and third pipes 11 and 12 are both DN25 seamless stainless steel pipes, and the inner diameter of the through-holes can be slightly larger than 25 mm. Since the regenerator walls are approximately 60 cm thick, the impact of providing through-holes with a diameter slightly larger than 25 mm on the regenerator's function is negligible.
[0028] The working principle of this utility model is as follows: First, gaseous ammonia reacts with nitrogen oxides in the flue gas within the active zone of the regenerator at 800°C-1100°C. The reaction mechanism is: 2NO + 4NH3 → 3N2 + 3H2O, 8NH3 + 6NO2 → 7N2 + 12H2O. This initially reduces nitrogen oxide emissions from the flue gas. Second, the flue gas that has undergone preliminary denitrification is collected in the flue gas manifold 6. The bath exhaust gas discharged through the exhaust outlet 3 reacts with the nitrogen oxides in the preliminarily denitrified flue gas, further removing nitrogen oxides from the flue gas. The reaction mechanism is: 2NO2 + 2H2 → N2 + H2O; 2NO + 5H2 → 2NH3 + 2H2O; 4NH3 + 4NO + O2 → 2N2 + 6H2O.
[0029] After undergoing two denitration steps, the flue gas enters the desulfurization and denitrification unit 7, reducing the load on the unit 7 and the amount of ammonia used. This eliminates the need to inject ammonia into the unit 7, thus reducing costs. This utility model simultaneously addresses the problem of excessive nitrogen oxides in the flue gas due to ammonia pump failure and the inefficient use of the nitrogen-hydrogen mixture emitted from the exhaust outlet 3. Since the hydrogen content of the bath exhaust gas is less than 1% upon entering the flue gas manifold 6, there is no risk of explosion.
[0030] The utility model uses the above-mentioned device to introduce ammonia into the combustion chambers on both sides of the kiln 2 in two ways, and asynchronously reverses the direction of the kiln 2 to react with the nitrogen oxides in the flue gas to achieve preliminary denitrification of the flue gas; by introducing the BATH tail gas (nitrogen-hydrogen mixed gas) discharged through the exhaust outlet 3 into the flue gas collecting pipe 6, the BATH tail gas reacts with the nitrogen oxides in the flue gas that has undergone preliminary denitrification to achieve secondary denitrification of the flue gas, thereby reducing the emission of nitrogen oxides, reducing the load of the desulfurization and denitrification device 7, reducing the amount of ammonia used, and reducing costs.
[0031] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.
Claims
1. A tin bath tail gas and ammonia SNCR-assisted denitrification device, comprising a tin bath, a kiln, a liquid ammonia tank, and a liquid ammonia gasification device. The front end of the tin bath is provided with an exhaust outlet, the left side of the kiln is provided with a left regenerator, and the right side of the kiln is provided with a right regenerator. The flue gases from the left and right regenerators are collected through a flue gas collection pipe and then transported to a desulfurization and denitrification device. The device is characterized in that: The exhaust outlet of the tin bath is connected to the flue gas collecting pipe through a first pipe, and a certain distance is spaced between the end of the first pipe away from the flue gas collecting pipe and the exhaust outlet; An adjustable baffle for maintaining a stable tin bath pressure is provided at one end of the first pipe away from the flue gas collecting pipe; The outlet of the liquid ammonia tank is connected to the liquid ammonia gasification device, the gaseous ammonia outlet of the liquid ammonia gasification device is connected to the left heat storage chamber of the kiln through a second pipe, and the gaseous ammonia outlet of the liquid ammonia gasification device is connected to the right heat storage chamber of the kiln through a third pipe. Automatic shut-off valves are provided on the second pipe and the third pipe.
2. The SNCR assisted denitration device for tin bath tail gas and ammonia according to claim 1, characterized in that: The distance between the end of the first pipe away from the flue gas collecting pipe and the exhaust outlet is 50 mm.
3. The SNCR assisted denitration device for tin bath tail gas and ammonia according to claim 2, characterized in that: One end of the first pipe away from the flue gas collecting pipe is in a trumpet shape that expands outward.
4. The SNCR assisted denitration device for tin bath tail gas and ammonia according to claim 3, characterized in that: The adjustable baffle is arranged at the trumpet-shaped port of the first pipeline.
5. The SNCR assisted denitration device for tin bath tail gas and ammonia according to claim 4, characterized in that: A through hole for accommodating the second pipe or the third pipe is provided on the wall of the left heat storage chamber and the right heat storage chamber, and the ends of the second pipe and the third pipe connected to the heat storage chamber are both located in the through hole and 20 mm away from the inner end of the through hole.
6. The SNCR-assisted denitration device for tin bath tail gas and ammonia according to claim 5, characterized in that: The diameters of the second pipe and the third pipe are both 25 mm.