Coating exhaust gas reprocessing system

Abstract

The utility model belongs to glass manufacturing technical field discloses a kind of coating waste gas reprocessing systems.The system includes tail gas collection pipeline, storage device, smelting furnace, desulfurization and denitrification device and discharge device, tail gas collection pipeline is used to collect the coating waste gas in coating room, storage device is connected with tail gas collection pipeline, and can store coating waste gas, smelting furnace and storage device are connected to set, and coating waste gas can be heated and decomposed, smelting furnace is used for the melting of glass raw material, desulfurization and denitrification device and smelting furnace are connected to set, and the combustion tail gas produced by combustion in smelting furnace can enter desulfurization and denitrification device, discharge device is connected to desulfurization and denitrification device, and the combustion tail gas after desulfurization and denitrification treatment can be discharged.The system can pass through storage device, can damp the fluctuation of coating waste gas concentration, avoid negative influence caused by fluctuation to normal production of smelting furnace, can realize efficient, energy-saving, stable, safe economic type processing to coating waste gas.

Description

Technical Field

[0001] This utility model relates to the field of glass manufacturing technology, and in particular to a coating waste gas reprocessing system. Background Technology

[0002] Coating processes (such as PVD and CVD) are key technologies in precision optics, semiconductors, and display panels. During their production, substrate cleaning, chamber purification, and chemical reactions utilize organic solvents (such as ethanol and acetone) and gaseous precursors (such as HMDSO), generating large volumes of low-concentration (typically below 800 mg / m³) volatile organic compounds (VOCs) with significant intermittent emission characteristics. Direct emission of these VOCs causes environmental pollution and health hazards; therefore, efficient purification is a mandatory requirement of environmental regulations.

[0003] Thermal combustion completely oxidizes VOCs into... and One of the most reliable technologies. Among them, regenerative thermal oxidation (RTO) technology has become the mainstream technology for treating large volumes of low- to medium-concentration industrial waste gas due to its high heat recovery efficiency (>95%), and has been attempted to be applied in the coating industry.

[0004] However, RTO technology has a significant effect on auxiliary fuels under low concentration conditions, resulting in poor operating economy and poor adaptability to intermittent production conditions. It also leads to serious waste of standby energy and safety risks when the concentration fluctuates.

[0005] Therefore, there is an urgent need for a coating waste gas reprocessing system to solve the above-mentioned technical problems. Utility Model Content

[0006] The purpose of this invention is to provide a coating waste gas reprocessing system that can treat coating waste gas at a low cost, has good operating economy, and can adapt to intermittent production conditions.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] The coating exhaust gas reprocessing system includes:

[0009] An exhaust gas collection pipe, which is used to collect coating waste gas in the coating room;

[0010] A storage device, which is connected to the exhaust gas collection pipe and is capable of storing the coating waste gas;

[0011] A melting furnace is connected to the storage device and is capable of heating the coating exhaust gas to above 1400 degrees Celsius for decomposition. The melting furnace is used for melting glass raw materials.

[0012] A desulfurization and denitrification device is provided, which is connected to the melting furnace. The combustion exhaust gas generated in the melting furnace can enter the desulfurization and denitrification device for desulfurization and denitrification treatment.

[0013] An emission device is connected to the desulfurization and denitrification device and is capable of emitting the combustion exhaust gas that has undergone desulfurization and denitrification treatment.

[0014] In some embodiments, the exhaust gas collection pipe includes a main pipe and at least two branch pipes, which are distributed at different locations within the coating chamber.

[0015] In some embodiments, an exhaust fan and an air collection hood are provided at the air inlet of the branch pipe.

[0016] In some embodiments, a first fan is provided between the main pipe and the storage device, the first fan being used to drive the coating exhaust gas into the storage device.

[0017] In some embodiments, the storage device includes a buffer pressure vessel, the volume of which is configured to store at least the amount of exhaust gas generated by the coating chamber over 2 hours.

[0018] In some embodiments, a temperature sensor is provided at the melting furnace, a gas supply pipe and a flow control valve are connected between the storage device and the melting furnace, the coating exhaust gas enters the melting furnace after passing through the gas supply pipe and the flow control valve, and the temperature sensor and the flow control valve are connected by a signal.

[0019] In some embodiments, the temperature sensor includes a thermocouple, and the upper limit for temperature detection of the thermocouple is at least 1500 degrees Celsius.

[0020] In some embodiments, a second fan is connected between the gas supply pipe and the flow control valve, the second fan being used to input the coating waste gas into the melting furnace.

[0021] In some embodiments, a reflux pipe and a reflux valve are provided between the furnace and the storage device. One end of the reflux pipe is connected between the second blower and the flow control valve, and the other end of the reflux pipe is connected to the storage device or the exhaust gas collection pipe. The reflux valve is used to control the opening and closing of the reflux pipe.

[0022] In some embodiments, a third fan is connected between the melting furnace and the desulfurization and denitrification device.

[0023] The above technical solution has the following advantages or beneficial effects:

[0024] This coating exhaust gas retreatment system avoids complex pretreatment or separate control of coating exhaust gas. Through the storage device, it can smooth out fluctuations in the concentration of coating exhaust gas, preventing fluctuations from negatively impacting the normal production of the melting furnace. It not only has low construction costs but also low operating costs, enabling efficient, energy-saving, stable, and safe economic treatment of coating exhaust gas. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the coating waste gas retreatment system of this utility model.

[0026] In the picture:

[0027] 1. Coating room; 2. Exhaust gas collection pipeline; 21. Main pipeline; 22. Branch pipeline; 221. Gas collection hood; 3. First fan; 4. Storage device; 5. Second fan; 6. Gas transmission pipe; 7. Melting furnace; 8. Third fan; 9. Desulfurization and denitrification device; 10. Emission device. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0029] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," "fixed," and "abutting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0031] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0032] When treating coating exhaust gas, the RTO system needs to utilize the heat released from the oxidation of VOCs contained in the exhaust gas itself. When the concentration of coating exhaust gas is extremely low, the calorific value within the RTO system is far insufficient to maintain the oxidation temperature required by the internal combustion chamber (typically ≥760℃). This means that when the concentration of coating exhaust gas is extremely low, the system must rely on auxiliary fuels such as natural gas for continuous combustion to avoid shutdown. Consequently, when the concentration of coating exhaust gas is insufficient, the operating cost of the RTO system is extremely high.

[0033] Meanwhile, when the coating equipment operates intermittently, the concentration of coating exhaust gas fluctuates over time, leading to the aforementioned increase in operating costs. This intermittent operation often stems from the batch nature of coating production, especially during idle periods such as equipment standby, maintenance, and production changeovers when no exhaust gas is generated. During these idle periods, the exhaust gas concentration is extremely low, necessitating the use of auxiliary materials such as natural gas to maintain the combustion chamber temperature. Furthermore, at the end of the idle period, i.e., during the initial coating process, there is a sudden and sharp increase in exhaust gas concentration. In some specific situations, the peak concentration may even exceed 25% of the lower explosive limit (LEL) (typical safety design value), posing a risk of combustion and explosion, causing a rapid increase in combustion chamber temperature, and potentially damaging the equipment.

[0034] like Figure 1 As shown, this utility model provides a coating waste gas re-treatment system that can treat coating waste gas at a low cost, has good operating economy, and can adapt to intermittent production conditions.

[0035] Specifically, the coating waste gas retreatment system includes a tail gas collection pipe 2, a storage device 4, a melting furnace 7, a desulfurization and denitrification device 9, and an emission device 10. One end of the tail gas collection pipe 2 extends into the coating chamber 1 and collects the coating waste gas generated during the glass coating process. The other end of the tail gas collection pipe 2 is connected to the storage device 4, and the collected coating waste gas can be input into the storage device 4. The storage device 4 can store the coating waste gas, thereby suppressing fluctuations in the concentration of the coating waste gas.

[0036] The storage device 4, melting furnace 7, desulfurization and denitrification device 9, and emission device 10 are sequentially connected. The melting furnace 7 is a furnace used for melting glass raw materials. The desulfurization and denitrification device 9 is a common device in related technologies used to treat the combustion exhaust gas of the melting furnace 7, capable of desulfurizing and denitrifying the combustion exhaust gas. The emission device 10 includes structures such as a chimney, used to discharge the desulfurized and denitrified combustion exhaust gas.

[0037] When the coating waste gas collected in storage device 4 enters melting furnace 7, the furnace is typically maintained at a temperature above 1400 degrees Celsius, much higher than the 760 degrees Celsius in the RTO system, to melt the glass raw materials. This allows the coating waste gas to be combusted. Under this temperature environment, the organic solvents and precursors in the coating waste gas can be completely decomposed. and The high removal efficiency (DRE) fundamentally solves the pollutant problem and avoids secondary pollution. Furthermore, since the melting furnace 7, desulfurization and denitrification device 9, and emission device 10 are common components in existing glass manufacturing enterprises, the high-temperature combustion environment within the melting furnace 7 can be directly utilized. This not only achieves the removal and destruction of coating waste gas but also utilizes it as part of the combustion air required by the melting furnace 7, realizing waste utilization and integrating the coating waste gas into an existing, mature, and stable treatment process. Finally, any new pollutants generated in the melting furnace 7 can also be removed by the desulfurization and denitrification device 9, ensuring that the final emissions fully meet standards.

[0038] Therefore, this coating exhaust gas retreatment system can avoid complex pretreatment or separate control of coating exhaust gas. Moreover, through the storage device 4, it can smooth out the fluctuations in the concentration of coating exhaust gas and avoid the fluctuations from negatively affecting the normal production of the melting furnace 7. It not only has low construction costs but also low operating costs, and can achieve efficient, energy-saving, stable, and safe economic treatment of coating exhaust gas.

[0039] like Figure 1As shown, in this embodiment, the exhaust gas collection pipe 2 includes a main pipe 21 and at least two branch pipes 22. The branch pipes 22 are distributed at different locations within the coating chamber 1, thereby collecting coating exhaust gas with high efficiency. Preferably, an exhaust fan and a gas collection hood 221 are provided at the air inlet of the branch pipe 22. The gas collection hood 221 can constrain the gas collection direction of the branch pipe 22, ensuring that the gas collection areas of multiple branch pipes 22 do not overlap, thus achieving high-efficiency collection of coating exhaust gas. The exhaust fan is a diagonal-flow exhaust fan with an airflow of up to 3500 cm³ / h, which can ensure sufficient coating exhaust gas collection efficiency.

[0040] Optionally, a first fan 3 is installed between the main pipe 21 and the storage device 4. The first fan 3 drives the coating waste gas into the storage device 4. The first fan 3 can maintain the airflow direction in the exhaust gas collection pipe 2 and also play a certain role in preventing backflow. For example, in this embodiment, the distance between the branch pipes 22 is 300mm, and the main pipe 21 is a 1600mm by 1600mm square pipe, and is equipped with a 180kW variable frequency first fan 3. When the coating process is carried out in the coating room 1, the variable frequency first fan 3 operates at a higher power, which has a good collection effect on the coating waste gas. When the coating room is in an idle period without waste gas generation, such as equipment standby, maintenance, or production changeover, the variable frequency first fan 3 can operate at a lower power to prevent backflow.

[0041] Continue to refer to Figure 1 As shown, the storage device 4 includes a buffer pressure vessel, the volume of which is configured to store the amount of waste gas generated by the coating chamber 1 within 2 hours. This is because the idle periods during which no waste gas is generated, such as equipment standby, maintenance, or production changeover, generally do not exceed 2 hours. Therefore, as long as the volume of the buffer pressure vessel is large enough, fluctuations in the concentration of coating waste gas can be mitigated.

[0042] Of course, since melting furnace 7 also needs to melt glass raw materials, directly introducing the coating waste gas from storage device 4 into the furnace would create a continuous and uncontrollable source of thermal disturbance. Generally, the stability and uniformity of the temperature field within melting furnace 7 are required to be extremely high, for example, temperature control accuracy within ±5℃ is required. The presence of a thermal disturbance source will directly affect the damage / splashing rate of the high-temperature resistant bricks in melting furnace 7 and the reaction process on the substrate surface, thus leading to glass defects.

[0043] like Figure 1As shown, in this embodiment, a temperature sensor is installed at the melting furnace 7, and a gas supply pipe 6 and a flow control valve are connected between the storage device 4 and the melting furnace 7. The coating waste gas can enter the melting furnace 7 after passing through the gas supply pipe 6 and the flow control valve. The temperature sensor and the flow control valve are connected by a signal, and the sensor can send a corresponding opening adjustment signal to the flow control valve according to the temperature change inside the melting furnace 7, so as to change the flow rate of the coating waste gas entering the melting furnace 7.

[0044] For example, when the temperature sensor detects that the temperature inside the melting furnace 7 is above 1450 degrees Celsius and rising towards 1500 degrees Celsius, it sends a signal to the flow control valve to reduce the opening, thereby reducing the input of coating exhaust gas and slowing down, lowering, and controlling the temperature rise. Of course, the temperature sensor can also be connected to the fuel input valve of the melting furnace 7 to synchronously send a signal to the fuel input valve to reduce its opening. Conversely, when the temperature sensor detects that the temperature inside the melting furnace 7 is below 1350 degrees Celsius and showing a decreasing trend, it can also send a signal to the flow control valve and the fuel input valve to increase their opening. Therefore, preferably, the temperature sensor includes a thermocouple, and the upper limit of the thermocouple's temperature detection is at least 1500 degrees Celsius.

[0045] Furthermore, a second fan 5 is connected between the gas supply pipe 6 and the flow control valve. The second fan 5 has a power of 220 kW and can stably input the coating waste gas into the melting furnace 7. Optionally, a return pipe and a return valve are also provided between the melting furnace 7 and the storage device 4. One end of the return pipe is connected between the second fan 5 and the flow control valve, and the other end of the return pipe is connected to the storage device 4. The return valve is used to control the opening and closing of the return pipe. When the upstream pressure (e.g., the pressure in the storage device 4) continues to rise, the return valve will open, allowing the coating waste gas to flow between the gas supply pipe 6 and the storage device 4, achieving the effect of partially buffering and cushioning the coating waste gas using the return pipe and the gas supply pipe 6, and preventing the pressure from continuously rising. Of course, in some embodiments, the return pipe can also be connected to the exhaust gas collection pipe 2, thereby further utilizing the exhaust gas collection pipe 2 to achieve a better buffering effect.

[0046] It should be noted that the reflux pipe can also be used to maintain the flow of coating waste gas in the storage device 4, thereby avoiding the formation of too much sediment in the storage device 4, and can also play a certain role in smoothing out the fluctuation of coating waste gas concentration.

[0047] Continue to refer to Figure 1 As shown, a third fan 8 connects the melting furnace 7 and the desulfurization and denitrification unit 9. The third fan 8 is preferably a high-power fan of 2000 kW, which draws the combustion exhaust gas into the desulfurization and denitrification unit 9 for centralized treatment. After treatment, the gas is then discharged through an emission device 10, such as a chimney.

[0048] Specifically, taking a temperature of 1450 degrees Celsius as an example, the following table shows the treatment data for various pollutants in the coating exhaust gas at this temperature:

[0049]

[0050] Table 1. Statistical Table of Pollutant Treatment Effectiveness

[0051] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0052] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A coating waste gas retreatment system, characterized in that, include: Exhaust gas collection pipe (2), the exhaust gas collection pipe (2) is used to collect coating waste gas in the coating room (1); Storage device (4), which is connected to the exhaust gas collection pipe (2) and is capable of storing the coating waste gas; A melting furnace (7) is connected to the storage device (4) and is capable of heating the coating exhaust gas to above 1400 degrees Celsius for decomposition. The melting furnace (7) is used for melting glass raw materials. A desulfurization and denitrification device (9) is provided, which is connected to the melting furnace (7). The combustion exhaust gas generated in the melting furnace (7) can enter the desulfurization and denitrification device (9) for desulfurization and denitrification treatment. The emission device (10) is connected to the desulfurization and denitrification device (9) and is capable of emitting the combustion exhaust gas that has been treated by desulfurization and denitrification.

2. The coating waste gas retreatment system according to claim 1, characterized in that, The exhaust gas collection pipe (2) includes a main pipe (21) and at least two branch pipes (22), which are distributed in different locations within the coating chamber (1).

3. The coating waste gas retreatment system according to claim 2, characterized in that, An exhaust fan and an air collection hood (221) are installed at the air inlet of the branch pipe (22).

4. The coating waste gas retreatment system according to claim 2, characterized in that, A first fan (3) is provided between the main pipe (21) and the storage device (4), and the first fan (3) is used to drive the coating waste gas into the storage device (4).

5. The coating waste gas retreatment system according to claim 1, characterized in that, The storage device (4) includes a buffer pressure vessel, the volume of which is configured to store at least the amount of exhaust gas generated by the coating chamber (1) within 2 hours.

6. The coating waste gas retreatment system according to claim 1, characterized in that, A temperature sensor is provided at the melting furnace (7). A gas supply pipe (6) and a flow control valve are connected between the storage device (4) and the melting furnace (7). The coating waste gas enters the melting furnace (7) after passing through the gas supply pipe (6) and the flow control valve. The temperature sensor and the flow control valve are connected by a signal.

7. The coating waste gas retreatment system according to claim 6, characterized in that, The temperature sensor includes a thermocouple, and the upper limit of the temperature detection range of the thermocouple is at least 1500 degrees Celsius.

8. The coating waste gas retreatment system according to claim 6, characterized in that, A second fan (5) is connected between the gas supply pipe (6) and the flow control valve. The second fan (5) is used to input the coating waste gas into the melting furnace (7).

9. The coating waste gas retreatment system according to claim 8, characterized in that, A reflux pipe and a reflux valve are also provided between the furnace (7) and the storage device (4). One end of the reflux pipe is connected between the second blower (5) and the flow control valve, and the other end of the reflux pipe is connected to the storage device (4) or the exhaust gas collection pipe (2). The reflux valve is used to control the opening and closing of the reflux pipe.

10. The coating waste gas retreatment system according to claim 1, characterized in that, A third blower (8) is connected between the furnace (7) and the desulfurization and denitrification device (9).

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