A comprehensive treatment device for flue gas from enamel kilns

Abstract

This utility model belongs to the field of flue gas treatment technology, specifically relating to a comprehensive flue gas treatment device for enamel glaze kilns, including a combustion supplement system, a heat dissipation system, a dust removal system, and a denitrification system. The combustion supplement system is connected to the kiln's flue outlet and is used to heat the discharged flue gas to prevent its temperature from falling below its dew point. One end of the heat dissipation system is connected to the combustion supplement system, and the other end is connected to the dust removal system, used to regulate the flue gas temperature so that the subsequent dust removal and denitrification systems operate within a suitable temperature range. The dust removal system is used to filter and remove dust from the flue gas. The dust-removed flue gas is then sent to the denitrification system, which performs denitrification treatment on the dust-removed flue gas. This utility model solves the problem of difficult treatment caused by the complex composition and large temperature fluctuations of enamel glaze kiln flue gas, simultaneously improving both environmental protection and economic benefits.

Description

Technical Field

[0001] This utility model relates to the technical field of flue gas treatment equipment, specifically to a comprehensive treatment device for flue gas from enamel kilns. Background Technology

[0002] The flue gas produced by enamel kilns has a complex composition, containing a large number of pollutants, including high concentrations of particulate matter, fluorides, nitrogen oxides (NOx), and alkali metal compounds. These pollutants not only have a significant impact on the ecological environment but also seriously endanger human health. Therefore, it is necessary to implement key control measures on critical components such as dust, fluorides, and NOx in the flue gas. In addition, due to the periodic nature of the feeding process of enamel kilns, the temperature of the emitted flue gas also fluctuates periodically, increasing the technical difficulty of comprehensive flue gas treatment in enamel kilns.

[0003] Currently, common industrial flue gas denitrification processes mainly include selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), and oxidation methods. While oxidation methods offer advantages such as low initial investment, simple equipment and processes, and high denitrification efficiency, they are prone to secondary pollution problems such as wastewater and ozone leakage during operation, and are no longer widely used in practical engineering. SNCR technology has relatively low denitrification efficiency and requires high reaction temperatures, which are often lacking in the required high-temperature range of enamel kiln flue gas, significantly limiting its application in enamel kiln flue gas treatment. Although SCR technology can achieve high denitrification efficiency, its catalyst is easily affected by flue gas composition. Alkali metal ions in enamel kiln flue gas can easily cause irreversible catalyst poisoning, while fluorides can cause severe corrosion to the catalyst support. To alleviate the aforementioned problems, some enamel kilns employ a pretreatment process of alkaline scrubbing of flue gas before heating it to enter the SCR system for flue gas denitrification. After alkaline scrubbing, the flue gas temperature drops to around 60°C, requiring significant energy to heat it to over 180°C to meet the operating temperature of the SCR catalyst, thus increasing operating costs. Furthermore, the flue gas inevitably contains some fluorine-containing substances after alkaline scrubbing, which may still corrode the catalyst and affect the long-term stable operation of the system. Therefore, this application aims to develop a highly efficient, stable, and economical comprehensive flue gas treatment device suitable for enamel kilns. Utility Model Content

[0004] The purpose of this utility model is to address some shortcomings of existing technologies and provide a comprehensive treatment device for flue gas from enamel kilns.

[0005] The technical solution of this utility model is: a comprehensive treatment device for flue gas from an enamel glaze kiln, comprising a combustion supplement system, a heat dissipation system, a dust removal system, and a denitrification system; the combustion supplement system is connected to the flue outlet of the kiln and is used to heat the discharged flue gas to prevent the flue gas temperature from falling below its dew point temperature; one end of the heat dissipation system is connected to the combustion supplement system, and the other end is connected to the dust removal system, used to regulate the temperature of the flue gas so that the subsequent dust removal system and denitrification system operate within a suitable temperature range; the dust removal system is used to filter and remove dust from the flue gas; the flue gas after dust removal is sent to the denitrification system; the denitrification system is used to denitrify the flue gas after dust removal.

[0006] The advantages of this solution are as follows: The flue gas emitted during the production process of enamel glaze kilns has a complex composition (containing large amounts of fluorides and alkali metals, etc.) and fluctuates significantly in temperature (due to the characteristics of its pool furnace production process, the temperature is relatively low during feeding, with the outlet flue gas temperature around 70℃; during normal heating, the outlet flue gas temperature can reach 350℃). Therefore, the comprehensive flue gas treatment device for enamel glaze kilns in this application uses a combustion supplement system and a heat dissipation system to uniformly regulate the temperature of the flue gas emitted during the enamel glaze kiln production process, ensuring that the subsequent dust removal and denitrification systems always operate within a suitable temperature range. Furthermore, because the particulate matter in the enamel kiln flue gas has a high fluoride content, the particulate matter must be removed first. The flue gas after dust removal is then connected to the denitrification system for further treatment, which helps extend the service life of the denitrification system.

[0007] Furthermore, the afterburning system consists of a fuel system, an air supply system, a mixing device, an ignition system, a combustion chamber, and a control system. Under the coordination of the control system, the fuel and air supplied by the fuel system and air supply system are fully mixed by the mixing device and ignited by the ignition system in the combustion chamber. Stable combustion generates high temperatures, thereby increasing the flue gas temperature. In summary, the afterburning system is used to heat the flue gas from low-temperature enamel glaze kilns, preventing the flue gas temperature from falling below the dew point temperature, which could cause corrosion and clogging of the bag filter. It also ensures the temperature required for SCR flue gas denitrification (generally between 200℃ and 350℃).

[0008] Furthermore, the heat dissipation system employs a tube-and-shell heat exchanger, with flue gas flowing through the tubes and cooling air flowing through the shell. The internal pipes are made of enamel-lined tubes to avoid corrosion caused by localized low temperatures, while the external casing is made of carbon steel or stainless steel. In one specific implementation, the heat dissipation system uses an enamel-lined tube heat exchanger, mainly composed of a shell, enamel-lined base tubes, an enamel glaze layer, and tube sheet fixing components. Its specific structure is existing technology and will not be elaborated here. The heat exchange capacity of the enamel-lined tube heat exchanger can be improved by incorporating enhanced heat transfer structures, including spiral internal finned tubes (increasing turbulence and improving the overall heat transfer coefficient) and external finned tubes (fins individually enamel-lined to expand the heat transfer area). The thermal conductivity of the enamel-lined tube heat exchanger is 0.8-1.2 W / (m·K); it has excellent acid resistance and can withstand 98% of H₂SO₄.

[0009] In another preferred embodiment, the heat dissipation system can also employ an enamel-lined plate heat exchanger, with flue gas flowing inside the enamel-lined plates and cooling air flowing outside; its internal piping is also made of enamel-lined plates. This enamel-lined plate heat exchanger combines traditional plate heat exchangers with enamel-lined corrosion protection technology, and consists of a functional layer structure, corrugated plate assemblies, a multi-functional frame system, an intelligent sealing system, and a flow channel network architecture. Through double-sided enamel-lined corrosion protection (0.3-0.5 mm glaze layer) and nano-hydrophobic surface treatment, the enamel-lined plate heat exchanger possesses superior corrosion resistance and anti-scaling capabilities. The enamel-lined plate heat exchanger is designed with a modular quick-disassembly design and an intelligent monitoring system, significantly reducing maintenance costs.

[0010] Furthermore, a conical dust hopper is installed at the bottom of the heat dissipation system to collect and clean the internal dust of the heat dissipation system in a timely manner.

[0011] Furthermore, the dust removal system adopts a bag filter dust collector; the bag filter dust collector adopts an offline blowing method, which facilitates online inspection of the bag clogging and replacement of the bag.

[0012] Furthermore, the filter bags of the bag filter are made of materials such as polyimide (long-term ≤240℃), glass fiber (long-term ≤260℃), PTFE (long-term ≤260℃), or basalt fiber (long-term ≤260℃).

[0013] Furthermore, the filtration velocity of the dust removal system is designed to be below 0.8 m / min to ensure that the dust concentration at the outlet of the dust removal system is below 10 mg / m³. 3 the following.

[0014] Furthermore, a temperature measuring device is installed at the inlet side of the dust removal system, allowing both the combustion system and the heat dissipation system to adjust their operating states based on the real-time measurement results from the temperature measuring device. Preferably, the temperature measuring device can be a thermocouple or a resistance temperature detector (RTD).

[0015] Furthermore, the denitrification system includes an SCR reactor, an ammonia supply system, a flue gas mixer, a rectifier grid, a soot blower, a medium-low temperature catalyst, and an induced draft fan. The ammonia supply system includes an ammonia-air mixer, a dilution fan, and an ammonia injection grid. The dilution fan pressurizes the clean flue gas at the outlet of the induced draft fan and sends it to the ammonia-air mixer for dilution and mixing with ammonia. The diluted ammonia is injected into the flue through the ammonia injection grid and mixed with the dust-removed flue gas by the flue gas mixer. After thorough mixing, it enters the SCR reactor and is then rectified by the rectifier grid before contacting the medium-low temperature catalyst. Denitrification is completed under the action of the catalyst.

[0016] Furthermore, the activity temperature range of the medium-low temperature catalyst is 180-350℃, and it is located after the rectifier grid; the outlet of the SCR reaction tower is connected to the alkaline washing system; under the action of the induced draft fan at the outlet, the flue gas that has undergone denitrification treatment is sent to the alkaline washing system for defluorination treatment.

[0017] Furthermore, a soot blower is installed at the top of the corresponding low-temperature catalyst to prevent dust from accumulating and clogging the catalyst.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows: The comprehensive treatment device for enamel glaze kiln flue gas of this application regulates the temperature of the flue gas emitted during the production process of enamel glaze kiln by setting up a combustion supplement system and a heat dissipation system, so that the dust removal system and denitrification system can always operate within a suitable temperature range, effectively reducing the risk of equipment operation and management, extending service life, and achieving the goal of saving equipment costs; it solves the problem of difficult treatment caused by the complex composition and large temperature fluctuation of enamel glaze kiln flue gas, and simultaneously improves environmental protection and economic benefits. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this utility model; In the diagram: 1. Heat exchanger; 2. Cooling fan; 3. Valve; 4. Pressure measuring device; 5. Temperature measuring device; 6. Combustion fan; 7. Valve assembly; 8. Burner; 9. Baghouse dust collector; 10. Ammonia injection grid; 11. Ammonia-air mixer; 12. Flue gas mixer; 13. SCR reaction tower; 14. Rectifying grid; 15. Catalyst; 16. Soot blower; 17. Dilution fan; 18. Exhaust fan. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments. Methods or functional components not specifically described in the embodiments are all prior art. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Example

[0021] like Figure 1 As shown, this embodiment is a comprehensive flue gas treatment device for enamel glaze kilns, including a combustion supplement system, a heat dissipation system, a dust removal system, and a denitrification system. The combustion supplement system is connected to the flue outlet of the kiln and is used to heat the discharged flue gas to prevent the flue gas temperature from falling below its dew point temperature. One end of the heat dissipation system is connected to the combustion supplement system, and the other end is connected to the dust removal system, used to regulate the temperature of the flue gas so that the subsequent dust removal and denitrification systems operate within a suitable temperature range. The dust removal system is used to filter and remove dust from the flue gas. The flue gas after dust removal is sent to the denitrification system, which is used to denitrify the flue gas after dust removal.

[0022] In this embodiment, the afterburning system consists of a fuel system, an air supply system, a mixing device, an ignition system, a combustion chamber, and a control system. Natural gas is used as fuel. The air supply system includes a combustion-supporting fan 6, the mixing device includes a valve assembly 7, and a burner 8 is installed in the combustion chamber. Under the coordination of the control system, the natural gas and air supplied by the fuel system and air supply system are fully mixed by the mixing device and ignited by the ignition system in the combustion chamber. Stable combustion generates high temperatures, thereby increasing the flue gas temperature. In summary, the afterburning system is used to heat the flue gas from a low-temperature enamel glaze kiln, preventing the flue gas temperature from falling below the dew point temperature, which could cause corrosion and clogging of the bag filter 9, while simultaneously ensuring the temperature required for SCR flue gas denitrification (between 200℃ and 350℃).

[0023] In this embodiment, the heat dissipation system adopts a tube-and-shell heat exchanger 1, with flue gas flowing through the tubes and cooling air flowing through the shell. The internal pipes are made of enamel-lined tubes to avoid corrosion caused by localized low temperatures, and the external casing is made of carbon steel or stainless steel. Specifically, the heat dissipation system uses an enamel-lined tube heat exchanger 1, which mainly consists of a shell, enamel-lined base tubes, enamel glaze layer, tube sheet fixing components, cooling fan 2, valves 3, etc. The enamel-lined tube heat exchanger 1 can improve its heat transfer capacity by setting enhanced heat transfer structures, including spiral inner finned tubes (increasing turbulence and improving the overall heat transfer coefficient) and outer finned tubes (fins individually enamel-lined to expand the heat transfer area). The thermal conductivity of the enamel-lined tube heat exchanger 1 is 0.8-1.2 W / (m·K); it has excellent acid resistance and can withstand 98% of H2SO4. A conical ash hopper can also be installed at the bottom of the heat dissipation system for timely collection and cleaning of internal dust.

[0024] In this embodiment, the dust removal system employs a bag filter 9. The bag filter 9 uses an offline blowing method, facilitating online inspection of bag clogging and replacement. The filter bags of the bag filter 9 can be made of polyimide. The filtration velocity of the dust removal system is designed to be below 0.8 m / min to ensure that the dust concentration at the system outlet is below 10 mg / m³.

[0025] In this embodiment, a temperature measuring device 5 and a pressure measuring device 4 are installed on the inlet side of the dust removal system. The control centers of the combustion system and the heat dissipation system are both connected to the temperature measuring device 5 and the pressure measuring device 4, and can adjust the working status in real time based on the measurement results of the temperature measuring device 5 and the pressure measuring device 4. Both the temperature measuring device 5 and the pressure measuring device 4 can be existing mature products; for example, the temperature measuring device 5 can be a thermocouple, and the pressure measuring device 4 can be a diaphragm-sealed pressure transmitter.

[0026] In this embodiment, the denitrification system includes an SCR reactor 13, an ammonia supply system, a flue gas mixer 12, a rectifier grid 14, a soot blower 16, a medium-low temperature catalyst 15, and an induced draft fan 18. The ammonia supply system includes an ammonia-air mixer 11, a dilution fan 17, and an ammonia injection grid 10. The dilution fan 17 pressurizes the clean flue gas at the outlet of the induced draft fan 18 and sends it to the ammonia-air mixer 11 for dilution and mixing with ammonia. The diluted ammonia is injected into the flue through the ammonia injection grid 10 and mixed with the dust-removed flue gas by the flue gas mixer 12. After thorough mixing, it enters the SCR reactor 13 and is then rectified by the rectifier grid 14 before contacting the medium-low temperature catalyst 15. The catalyst 15 has four layers (three in use and one as a backup), and denitrification is completed under the action of the catalyst 15. Soot blowers 16 are correspondingly provided at the upper end of each medium-low temperature catalyst 15 to prevent dust accumulation and blockage of the catalyst 15.

[0027] In this embodiment, the medium-low temperature catalyst 15 has an activity temperature range of 180-350℃ and is located after the rectifier grid 14; the outlet of the SCR reaction tower 13 is connected to the alkaline scrubbing system; under the action of the induced draft fan 18 at the outlet, the flue gas that has undergone denitrification treatment is sent to the alkaline scrubbing system for defluorination treatment to meet the corresponding emission requirements.

[0028] The comprehensive treatment device for enamel glaze kiln flue gas in this embodiment can effectively reduce the operation and management risks of related equipment and achieve the goal of saving operating costs; it solves the problem that the flue gas composition of enamel glaze kiln is complex and the temperature fluctuation is large, making it difficult to treat, and simultaneously improves environmental protection and economic benefits.

[0029] The above are only some embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various combinations and modifications of the aforementioned technical features. Any improvements, modifications, equivalent substitutions, or applications of the structure or method of the present utility model to other fields to achieve the same effect without departing from the spirit and scope of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A comprehensive treatment device for flue gas from an enamel kiln, characterized in that: This includes a combustion system, a heat dissipation system, a dust removal system, and a denitrification system; The supplementary combustion system is connected to the flue outlet of the kiln and is used to heat the discharged flue gas to prevent the temperature of the flue gas from falling below its dew point temperature. One end of the heat dissipation system is connected to the combustion system, and the other end is connected to the dust removal system. It is used to regulate the temperature of the flue gas so that the subsequent dust removal system and denitrification system can work within a suitable temperature range. The dust removal system is used to filter and remove dust from the flue gas; the flue gas after dust removal is sent to the denitrification system. The denitrification system performs denitrification treatment on the flue gas after dust removal.

2. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 1, characterized in that: The combustion system consists of a fuel system, an air supply system, a mixing device, an ignition system, a combustion chamber, and a control system. Under the coordination of the control system, the fuel and air supplied by the fuel system and the air supply system are fully mixed by the mixing device and ignited by the ignition system in the combustion chamber. Stable combustion generates high temperature, thereby increasing the flue gas temperature.

3. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 1, characterized in that: The heat dissipation system adopts a tube-and-shell heat exchanger, with flue gas flowing through the tubes and cooling air flowing through the shell. The internal pipes are made of enamel tubes to avoid corrosion caused by local low temperatures, and the external casing is made of carbon steel or stainless steel.

4. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 3, characterized in that: The heat dissipation system uses an enamel-lined tube heat exchanger with a thermal conductivity of 0.8-1.2 W / (m·K) and is resistant to 98% H2SO4.

5. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 1, characterized in that: The heat dissipation system uses an enamel plate heat exchanger, with flue gas flowing inside the enamel plate and cooling air flowing outside the enamel plate; its internal pipes are also made of enamel plates.

6. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 1, characterized in that: The bottom of the heat dissipation system is equipped with a conical dust hopper for timely collection and cleaning of the internal dust of the heat dissipation system.

7. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 1, characterized in that: The dust removal system employs a bag filter; the bag filter uses an offline blowing method, facilitating online inspection of bag clogging and replacement; the filter bags are made of polyimide, glass fiber, PTFE, or basalt fiber; the filtration velocity of the dust removal system is designed to be below 0.8 m / min to ensure a dust concentration of 10 mg / m³ at the system outlet. 3 the following.

8. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 7, characterized in that: The dust removal system is equipped with a temperature measuring device at its inlet. Both the combustion system and the heat dissipation system adjust their operating status based on the real-time measurement results from the temperature measuring device.

9. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 1, characterized in that: The denitrification system includes an SCR reactor, an ammonia supply system, a flue gas mixer, a rectifier grid, a soot blower, a medium-low temperature catalyst, and an induced draft fan. The ammonia supply system includes an ammonia-air mixer, a dilution fan, and an ammonia injection grid. The dilution fan pressurizes the clean flue gas at the outlet of the induced draft fan and sends it to the ammonia-air mixer to dilute and mix with the ammonia. The diluted ammonia is injected into the flue through the ammonia injection grid and mixed with the dust-removed flue gas by the flue gas mixer. After thorough mixing, it enters the SCR reactor and is then rectified by the rectifier grid before contacting the medium-low temperature catalyst. Denitrification is completed under the action of the catalyst.

10. The comprehensive treatment device for enamel glaze kiln flue gas according to claim 9, characterized in that: The medium-low temperature catalyst has an activity temperature range of 180-350℃ and is located after the rectifier grid; the outlet of the SCR reaction tower is connected to the alkaline washing system; under the action of the induced draft fan at the outlet, the flue gas that has undergone denitrification treatment is sent to the alkaline washing system for defluorination treatment.

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