Waste gas treatment system and method for asphalt waterproofing membrane production

Abstract

The present invention discloses a waste gas treatment system and method for the production of asphalt waterproofing membranes, belonging to the field of waste gas treatment. The system includes a cooling and oil removal device, a washing device, a gas-liquid separation device, and an incineration device, which are connected in sequence; the cooling and oil removal device is connected to the waste gas outlet of the asphalt reaction device. The method is that the waste gas is successively subjected to cooling and oil removal and secondary oil removal, the waste gas after oil removal is subjected to two-stage washing and then gas-liquid separation, and the separated gas is incinerated and then discharged. The system is designed with a two-stage oil removal device for oil removal, a two-stage washing absorption and waste gas incineration system, so as to efficiently and thoroughly convert the waste gas into carbon dioxide and water, without generating other pollutants, and with low operating and maintenance costs.

Description

Technical Field

[0001] The present invention relates to the field of waste gas treatment, and in particular to a waste gas treatment system for asphalt waterproofing membrane production;

[0002] The invention also relates to a method for treating waste gas from the production of asphalt waterproofing coiled materials. Background Art

[0003] Asphalt is a byproduct of petroleum refining and processing. Its primary components are macromolecular organic compounds found in petroleum, and its composition is highly complex. Asphalt is used extensively in daily life, primarily in road paving. Asphalt waterproofing membranes are a key asphalt product. Asphalt waterproofing membranes are manufactured by modifying asphalt to produce modified asphalt. They are widely used for rooftop waterproofing and anti-seepage.

[0004] The production process for asphalt waterproofing membranes requires heating the asphalt to approximately 200°C. At high temperatures, low-boiling-point substances in the asphalt volatilize, generating organic waste gas. The primary pollutants in this waste gas include asphalt fumes, benzopyrene, and volatile organic compounds (VOCs), along with sulfur-containing, odorous substances. Furthermore, the high-temperature asphalt fume generated during production can condense in pipes, eventually clogging them and making them difficult to clean or even causing them to become scrapped.

[0005] Existing technologies for treating waste gas from asphalt waterproofing membrane production typically rely on water washing, wet electrostatic treatment, and photocatalytic oxidation. While these technologies are effective for treating asphalt fumes, they are less effective for treating volatile organic compounds (VOCs) and odorous substances.

[0006] Asphalt waterproofing membrane production produces asphalt fumes. These tiny particles easily adhere to pipe walls and equipment interiors, making equipment maintenance difficult. Water washing processes are inefficient for removing these fumes. Furthermore, the washing process produces wastewater containing oil, which requires separate treatment, increasing wastewater treatment costs.

[0007] Wet electrostatic treatment involves high voltage, which poses a safety hazard, is unsafe, and is difficult to maintain. Photocatalytic treatment, on the other hand, produces ozone, which can lead to ozone problems.

[0008] Therefore, it is difficult for existing treatment processes to completely decompose and treat the waste gas from waterproofing membranes. In view of this, this application is specially proposed. Summary of the Invention

[0009] The present invention provides a waste gas treatment system and method for the production of asphalt waterproofing membranes. By designing a two-stage oil removal device for oil removal, a two-stage washing and absorption system, and an exhaust gas incineration system, the exhaust gas is efficiently and thoroughly converted into carbon dioxide and water without generating other pollutants and with low operating and maintenance costs.

[0010] The specific technical solutions of the present invention are as follows:

[0011] A waste gas treatment system for asphalt waterproofing membrane production includes a cooling and oil removal device, a washing device, a gas-liquid separation device and an incineration device connected in sequence; the cooling and oil removal device is connected to the waste gas outlet of the asphalt reaction device.

[0012] During the production of modified asphalt waterproofing membranes, asphalt, asphalt base oil, and modified resins are added to an asphalt reactor, where they are heated to approximately 200°C and stirred. This stirring process generates flue gas, which is then discharged through a flue gas control valve and piped into the exhaust gas treatment system. The main pollutants in the asphalt flue gas from the asphalt reactor include asphalt fumes and non-methane hydrocarbons.

[0013] Furthermore, the cooling and oil removal device includes a primary cooling and oil removal tank connected to the exhaust gas outlet of the asphalt reaction device and a secondary oil remover connected to the primary cooling and oil removal tank.

[0014] Preferably, the primary cooling and oil removal tank is an aeration tank.

[0015] More preferably, the aeration tank includes a transversely disposed aeration main pipe at the bottom and a plurality of transversely distributed lateral pipes connected to the aeration main pipe, each of the lateral pipes being provided with a plurality of aeration holes. The upper end of the aeration main pipe is connected to the exhaust gas outlet of the asphalt reaction unit. A fan operates to maintain a negative pressure in the aeration tank.

[0016] The exhaust gas from the asphalt reaction unit comes into contact with the asphalt base oil in the aeration tank through the aeration holes, cooling the asphalt flue gas while absorbing the asphalt smoke and particulate matter in the asphalt flue gas. A cooling water cooling coil is installed in the tank to cool the asphalt base oil.

[0017] Further preferably, the aeration holes are all arranged downward to prevent dust particles from clogging the aeration tube.

[0018] More preferably, the transverse branches in the aeration tank are curved with downward-pointing ends. This prevents liquid from accumulating in the transverse branches, achieving better results. Furthermore, the main aeration pipe can be serpentine, with a sharper bend at the intersection with the curved branches, for better material distribution.

[0019] Preferably, the interior of the secondary oil remover is a baffle structure, which removes large tar particles in the exhaust gas through inertial collision filtration.

[0020] The scrubbing device generally includes a primary scrubber and a secondary scrubber connected in sequence, wherein the gas inlet of the primary scrubber is connected to the gas outlet of the secondary degreaser. The absorption liquid of the two-stage scrubbing is asphalt production base oil, which can well absorb asphalt smoke.

[0021] Preferably, both the primary and secondary scrubbers are equipped with packing, more preferably random packing, which increases the gas-liquid contact area and enhances the scrubbing effect. Furthermore, wire mesh demisters and liquid distributors are installed at the tops of the primary and secondary scrubbers. The base oil after two-stage base oil absorption is regularly replaced and reused as asphalt base oil in the asphalt reactor.

[0022] The gas-liquid separation device is preferably a gas-liquid separator filled with wire mesh filler, which is used to remove liquid droplets entrained in the exhaust gas.

[0023] The primary cooling and degreasing tank has a liquid outlet at its lower end, which communicates with the asphalt reaction unit. Asphalt base oil is a softening oil added during the production of asphalt waterproofing membranes, primarily to soften the asphalt. The base oil in the primary cooling and degreasing tank is recyclable and flows directly into the asphalt reaction unit through the liquid outlet, eliminating the generation of waste oil. After passing through the primary cooling and degreasing tank, the flue gas temperature is reduced, removing most of the asphalt fumes.

[0024] A fan is also installed between the gas-liquid separation device and the incineration device to create negative pressure upstream of the system. Preferably, the fan is a centrifugal fan. The exhaust gas is then fed into the subsequent incineration device, which is preferably a regenerative incinerator. This incinerator maintains an incineration temperature of 800°C and utilizes thermal storage ceramics to increase heat utilization. This is typically a three-bed regenerative incinerator. After the exhaust gas is thoroughly incinerated and oxidized by the incineration device, the organic pollutants in the exhaust gas are completely oxidized into carbon dioxide and water before entering the chimney for emission compliance.

[0025] The present invention also provides a waste gas treatment method based on the above system, wherein the waste gas from the asphalt reaction device is cooled for oil removal and then subjected to secondary oil removal. The waste gas after oil removal is subjected to two-stage washing and then to gas-liquid separation. The separated gas is incinerated and then discharged.

[0026] The waste gas treatment system of the present invention can efficiently and thoroughly convert waste gas into carbon dioxide and water by designing a two-stage oil removal device for oil removal, a two-stage washing and absorption system, and an exhaust gas incineration system. First, the first-stage cooling and oil removal tank can absorb and cool the asphalt smoke and dust in the exhaust gas nearby, preventing a large amount of asphalt condensation in the subsequent pipeline from adhering to the pipe wall and causing blockage. Secondly, the two-stage washing and absorption of the base oil can absorb the asphalt smoke and dust in the exhaust gas. The absorbed base oil can be directly added to the reactor for reuse without generating waste oil and wastewater. Finally, the exhaust gas eventually enters the incineration device for oxidation treatment. The oxidation is complete, and the organic matter in the exhaust gas is completely oxidized into carbon dioxide and water. It can not only thoroughly treat the volatile organic matter in the exhaust gas, but also remove odorous substances and improve the treatment efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope of the present invention.

[0028] Figure 1 It is a schematic structural diagram of the exhaust gas treatment system of the present invention;

[0029] Figure 2 It is a structural schematic diagram of the aeration tank in the present invention.

[0030] Description of reference numerals:

[0031] 1. Asphalt mixing kettle; 2. Mixing kettle valve; 3. Mixing kettle exhaust gas collection pipe; 4. Primary cooling and oil removal tank; 5. Secondary oil remover; 6. Primary scrubber; 7. Secondary scrubber; 8. Gas-liquid separator; 9. Centrifugal fan; 10. Regenerative incinerator; 11. Chimney; 12. Base oil control valve; 13. Base oil pipeline; 14. Primary base oil lifting pump; 15. Secondary base oil lifting pump; 16. Random packing; 17. Wire mesh packing; 401. Aeration main pipe; 402. Horizontal aeration branch pipe; 403. Aeration tank shell; 404. Aeration hole. DETAILED DESCRIPTION

[0032] The embodiments of the present invention will be described in detail below with reference to specific examples, but those skilled in the art will appreciate that the following examples are intended only to illustrate the present invention and should not be construed as limiting the scope of the present invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0033] Example 1

[0034] An exhaust gas treatment system for asphalt waterproofing membrane production, such as Figure 1 As shown, it includes a cooling and oil removal device, a washing device, a gas-liquid separation device and an incineration device which are connected in sequence; the cooling and oil removal device is connected to the exhaust gas outlet of the asphalt mixing kettle 1.

[0035] The waste gas is controlled by the stirred tank valve 2 and discharged through the stirred tank waste gas collection pipe 3 to enter the waste gas treatment system.

[0036] The cooling and oil removal device includes a primary cooling and oil removal tank 4 connected to the exhaust gas outlet of the asphalt mixing kettle 1 and a secondary oil remover 5 connected to the primary cooling and oil removal tank 4 .

[0037] The first-level cooling and oil removal tank 4 is an aeration tank.

[0038] like Figure 2 As shown, the aeration tank is enclosed by an aeration tank shell 403. The interior includes an aeration main pipe 401 disposed horizontally at the bottom and several transverse aeration branches 402 connected to the aeration main pipe 401. Each transverse aeration branch pipe 402 is provided with a plurality of aeration holes 404. The upper end of the aeration main pipe 401 is connected to the exhaust gas outlet of the asphalt mixing kettle 1. The aeration tank is maintained in a negative pressure state by the fan.

[0039] The exhaust gas from the asphalt mixing kettle 1 contacts the asphalt base oil in the aeration tank through the aeration holes 404, cooling the asphalt flue gas while absorbing the asphalt smoke and particulate matter in the asphalt flue gas. The aeration tank is provided with a cooling water cooling coil for cooling the asphalt base oil.

[0040] The aeration holes 404 are all arranged downward to prevent dust particles from clogging the aeration pipe.

[0041] In a preferred embodiment, the transverse aeration branch pipes 402 in the aeration tank can be formed into curved branches with drooping ends. This prevents liquid from accumulating in the transverse branches, achieving better results. Furthermore, the main aeration pipe 401 can be formed into a serpentine pipe, with a particularly large curvature at the intersection with the curved branch pipe, to better distribute the material.

[0042] The interior of the secondary oil remover 5 is a baffle structure, which removes large tar particles in the exhaust gas through inertial collision filtration.

[0043] The scrubbing apparatus comprises a primary scrubber 6 and a secondary scrubber 7, connected in sequence. The gas inlet of the primary scrubber 6 is connected to the gas outlet of the secondary degreaser 5. The absorption liquid in both scrubbers is asphalt production base oil, which effectively dissolves asphalt fumes. The base oil is delivered to the top of the scrubbers by a primary base oil lift pump 14 and a secondary base oil lift pump 15, respectively, located outside the primary scrubber 6 and secondary scrubber 7. The base oil absorbs asphalt fumes and particulate matter from the exhaust gas through countercurrent contact.

[0044] Random packing 16 is installed inside both the primary and secondary scrubbers 6 and 7, further increasing the gas-liquid contact area and enhancing the scrubbing effect. A wire mesh demister and liquid distributor are also installed at the tops of the primary and secondary scrubbers 6 and 7. The base oil after two levels of base oil absorption is regularly replaced and then added to the asphalt mixing kettle 1 for reuse as asphalt base oil.

[0045] The gas-liquid separation device is a gas-liquid separator 8 filled with a wire mesh filler 17, which is used to remove liquid droplets entrained in the exhaust gas.

[0046] A liquid outlet is provided at the lower end of the primary cooling and oil removal tank 4 , and the liquid outlet is connected to the asphalt mixing kettle 1 through a base oil control valve 12 and a base oil pipeline 13 .

[0047] A centrifugal fan 9 is installed between the gas-liquid separator 8 and the incinerator to maintain negative pressure upstream of the system. Exhaust gas is fed through the centrifugal fan 9 into the subsequent incinerator. In this embodiment, the incinerator is a regenerative incinerator 10, which maintains an incineration temperature of 800°C and utilizes thermal storage ceramics to increase heat utilization. After the exhaust gas is thoroughly incinerated and oxidized in the regenerative incinerator 10, the organic pollutants in the exhaust gas are completely oxidized into carbon dioxide and water before entering a chimney 11 for discharge in compliance with emission standards.

[0048] The exhaust gas from the asphalt mixing kettle 1 is cooled and degreased and then degreased twice. The degreased exhaust gas is washed and absorbed in two stages before being separated into gas and liquid. The separated gas is incinerated and then discharged.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0050] Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the present invention and to form different embodiments. For example, in the claims above, any of the claimed embodiments may be used in any combination. The information disclosed in this background section is intended solely to enhance understanding of the overall background of the present invention and should not be construed as an admission or any form of implication that such information constitutes prior art known to those skilled in the art.

Claims

1. An exhaust gas treatment system for asphalt waterproofing membrane production, characterized in that: It includes a cooling and oil removal device, a washing device, a gas-liquid separation device and an incineration device which are connected in sequence; the cooling and oil removal device is connected to the exhaust gas outlet of the asphalt reaction device, and a fan is provided between the gas-liquid separation device and the incineration device to create a negative pressure upstream of the system; The cooling and oil removal device includes a primary cooling and oil removal tank connected to the exhaust gas outlet of the asphalt reaction device and a secondary oil remover connected to the primary cooling and oil removal tank; The first-stage cooling and oil removal tank is an aeration tank, which includes an aeration main pipe arranged horizontally at the bottom and a plurality of transversely distributed transverse branches connected to the aeration main pipe, each of the transverse branches is provided with a plurality of aeration holes, and the upper end of the aeration main pipe is connected to the exhaust gas outlet of the asphalt reaction device; The first-level cooling and oil removal tank is provided with a cooling water cooling coil for cooling the asphalt base oil; The first-level cooling and oil removal tank is in a negative pressure state; The lower end of the primary cooling and oil removal tank is provided with a liquid outlet, and the liquid outlet is connected to the asphalt reaction device; the lower end of the primary cooling and oil removal tank is provided with a liquid outlet, and the liquid outlet is connected to the asphalt reaction device through a base oil control valve and a base oil pipeline; The washing device includes a primary washing tower and a secondary washing tower connected in sequence, and the gas inlet of the primary washing tower is connected to the gas outlet of the secondary oil remover; the two-stage washing absorption liquid is asphalt base oil; the base oil after the two-stage base oil absorption is replaced regularly, and the replaced base oil is added to the asphalt reaction device as asphalt base oil for reuse.

2. The waste gas treatment system for asphalt waterproofing membrane production according to claim 1 is characterized in that: The aeration holes are all arranged downward.

3. The waste gas treatment system for the production of asphalt waterproofing membrane according to any one of claims 1-2, characterized in that: The interior of the secondary oil remover is a baffle structure.

4. A method for treating waste gas based on the system according to any one of claims 1 to 3, characterized in that: The waste gas from the asphalt reaction device is successively cooled for oil removal and subjected to secondary oil removal. The waste gas after oil removal is subjected to two-stage washing and then to gas-liquid separation. The separated gas is incinerated and then discharged.

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