Waste gas treatment device and method

Abstract

The present invention provides a waste gas treatment device and method. Waste gas passes through a first-stage tower spray layer, and the oxidant in the alkali solution sprayed by the first-stage tower spray layer can absorb hydrogen sulfide, methyl mercaptan and methyl sulfide in the oxidized waste gas, and can also partially absorb and oxidize ammonia and VOC in the waste gas. The first-stage tower demisting layer removes water from the waste gas, and the waste gas after water removal undergoes an oxidation reaction with ozone discharged from an ozone aeration disk, and ozone performs secondary oxidation on ammonia and VOC in the waste gas. Finally, the alkali solution sprayed by the second-stage tower spray layer absorbs and neutralizes the decomposition products of the waste gas, and absorbs ammonia again, thereby achieving decomposition and absorption of harmful substances in the waste gas, and excluding non-toxic and harmless gases.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and in particular to a waste gas treatment device and method. Background Art

[0002] During the discharge, transfer and purification of sewage, polluting gases are inevitably generated, especially compound malodorous gases, which seriously affect the health of workers and the normal life of surrounding residents. The presence of malodorous substances seriously affects the lives of residents, and the malodorous substances generated by sewage treatment plants and sewage lifting pump stations are one of the main sources; early sewage pools were open concrete structures. With the improvement of environmental protection requirements, sewage pools were covered or covered with films, and waste gas was led out of pipes for unified treatment; the early treatment equipment was a single process such as activated carbon adsorption, UV photolysis, low-temperature plasma, and simple acid-base spray towers; with the improvement of national emission standards, single processes are constantly updated or combined because of low efficiency and substandard emission gases; and sewage plant waste gas is not suitable for various concentration, condensation, combustion and other processes because of its large waste gas volume and low pollutant concentration. In the existing technology, acid spray, alkali spray, sodium hypochlorite oxidation and alkali spray are generally used to treat waste gas.

[0003] However, the oxidation product of sodium hypochlorite has a pungent odor and is prone to produce chlorine-containing polluted gas; and when sodium hypochlorite oxidizes waste gas, the oxidation reaction is short, resulting in incomplete oxidation and incomplete waste gas treatment. Therefore, an effective treatment equipment is urgently needed to effectively treat the waste gas to meet emission requirements. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides an exhaust gas treatment device and method to effectively treat the exhaust gas to meet the emission requirements.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] The first aspect of the present invention discloses an exhaust gas treatment device, which is applicable to a sewage station or a sewage lifting pump station, and comprises: a primary tower, a secondary tower, a primary tower spray layer, a primary tower demisting layer, an ozone aeration plate and a secondary tower spray layer;

[0007] The first-stage tower spray layer, the first-stage tower demisting layer and the ozone aeration plate are sequentially arranged in the first-stage tower along the exhaust gas flow direction;

[0008] The secondary tower spray layer is arranged in the secondary tower;

[0009] The air outlet of the first-level tower is connected to the air inlet of the second-level tower;

[0010] The first-stage tower spray layer is used to spray a mixed liquid that produces an oxidation reaction with the incoming exhaust gas, the ozone aeration plate is used to introduce ozone that produces a homogeneous reaction with the defogged exhaust gas, and the second-stage tower spray layer is used to spray an alkaline solution that absorbs and neutralizes the decomposition products of the exhaust gas.

[0011] Preferably, the number of the first-level tower spray layers is multiple, and the multiple first-level tower spray layers are divided into multiple groups and arranged in sequence in the first-level tower along the exhaust gas flow direction;

[0012] And / or, the number of the secondary tower spray layers is multiple, and the multiple secondary tower spray layers are divided into multiple groups and arranged in sequence in the secondary tower along the flow direction of the exhaust gas.

[0013] Preferably, the spraying direction of the first-stage tower spray layer and / or the second-stage tower spray layer is opposite to the flow direction of the exhaust gas.

[0014] Preferably, it further comprises a guide layer arranged downstream of the ozone aeration plate.

[0015] Preferably, it also includes: a secondary tower demisting layer;

[0016] The plurality of secondary tower demisting layers are arranged downstream of the secondary tower spraying layer.

[0017] Preferably, it also includes: a primary tower circulating water tank and a primary tower circulating pump;

[0018] The primary tower circulating water tank is arranged at the bottom of the primary tower and is used to collect the mixed solution of the alkali solution and the oxidant in the primary tower;

[0019] The primary tower circulating water tank is connected to the primary tower spray layer through the primary tower circulating pump.

[0020] Preferably, it also includes: a secondary tower circulating water tank and a secondary tower circulating pump;

[0021] The secondary tower circulating water tank is arranged at the bottom of the secondary tower and is used to collect the alkali solution in the secondary tower;

[0022] The secondary tower circulating water tank is connected to the secondary tower demisting layer through the secondary tower circulating pump.

[0023] Preferably, it also includes: an oxidant storage tank, an oxidant pump, an alkali solution storage tank and an alkali solution pump;

[0024] The oxidant storage tank is connected to the outlet of the primary tower circulation pump through the oxidant pump;

[0025] The alkali solution storage tank is connected to the primary tower circulating water tank and / or the secondary tower circulating water tank through the alkali solution pump.

[0026] Preferably, it also includes an ozone tail gas alarm arranged at the gas outlet of the secondary tower.

[0027] Preferably, it also includes an ozone generator for generating ozone;

[0028] The ozone generator is in communication with the ozone aeration disk.

[0029] The second aspect of the present invention discloses a method for treating waste gas, comprising the steps of:

[0030] S1, contacting the waste gas with a mixed solution, wherein the mixed solution includes an oxidant and an alkali solution;

[0031] S2, demisting the exhaust gas;

[0032] S3, introducing ozone to allow the ozone to react with the exhaust gas in a homogeneous manner;

[0033] S4. Absorbing and neutralizing the products of the oxidative decomposition of the exhaust gas.

[0034] From the above content, it can be seen that the present invention discloses a waste gas treatment equipment and method, wherein the first-level tower spray layer, the first-level tower demisting layer and the ozone aeration plate are arranged in the first-level tower in sequence along the waste gas flow direction; the second-level tower spray layer is arranged in the second-level tower; the air outlet of the first-level tower is connected to the air inlet of the second-level tower; the first-level tower spray layer is used to spray a mixed liquid that produces an oxidation reaction with the incoming waste gas, the ozone aeration plate is used to introduce ozone that produces a homogeneous reaction with the demisted waste gas, and the second-level tower spray layer is used to spray an alkaline solution that absorbs and neutralizes the decomposition products of the waste gas. Through the above-disclosed waste gas treatment equipment and method, the waste gas passes through the first-level tower spray layer, and the oxidant in the alkali solution sprayed by the first-level tower spray layer can absorb and oxidize hydrogen sulfide, methyl mercaptan and methyl sulfide in the waste gas, and can also partially absorb and oxidize the ammonia and VOC in the waste gas. The first-level tower demisting layer removes water from the waste gas, and the waste gas after dehydration undergoes an oxidation reaction with the ozone discharged from the ozone aeration disk. The ozone performs secondary oxidation on the ammonia and VOC in the waste gas. Finally, the alkali solution sprayed by the second-level tower spray layer absorbs and neutralizes the decomposition products of the waste gas, and absorbs the ammonia again, thereby achieving the decomposition and absorption of harmful substances in the waste gas and removing non-toxic and harmless gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0036] Figure 1 A schematic diagram of the structure of an exhaust gas treatment device provided by an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of a process for treating waste gas by a waste gas treatment device provided in an embodiment of the present invention;

[0038] Figure 3 A process diagram of treating waste gas by a waste gas treatment device provided in an embodiment of the present invention.

[0039] Among them, there are waste gas inlet 1, waste gas outlet 2, first-level tower spray layer 3, first-level tower demisting layer 4, ozone aeration plate 5, diversion layer 6, inter-tower connecting pipe 7, second-level tower spray layer 8, second-level tower demisting layer 9, first-level tower circulating water tank 10, first-level tower circulating pump 11, oxidant storage tank 12, oxidant dosing pump 13, second-level tower circulating water tank 14, second-level tower circulating pump 15, alkali solution storage tank 16, alkali solution pump 17, ozone generator 18 and ozone tail gas alarm 19. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] In this application, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0042] The embodiment of the present invention provides an exhaust gas treatment device, see Figure 1 , Figure 1 It is a structural schematic diagram of the waste gas treatment equipment, which is suitable for a sewage station or a sewage lifting pump station, and includes: a primary tower, a secondary tower, a primary tower spray layer 3, a primary tower demisting layer 4, an ozone aeration plate 5 and a secondary tower spray layer 8;

[0043] The first-stage tower spray layer 3, the first-stage tower demisting layer 4 and the ozone aeration plate 5 are sequentially arranged in the first-stage tower along the exhaust gas flow direction;

[0044] The secondary tower spray layer 8 is arranged in the secondary tower;

[0045] The air outlet of the first-level tower is connected to the air inlet of the second-level tower;

[0046] The first-stage tower spray layer 3 is used to spray a mixed liquid that produces an oxidation reaction with the incoming exhaust gas, the ozone aeration plate 5 is used to introduce ozone that produces a homogeneous reaction with the defogged exhaust gas, and the second-stage tower spray layer 8 is used to spray an alkaline solution that absorbs and neutralizes the decomposition products of the exhaust gas.

[0047] It should be noted that the mixed liquid sprayed out by the spray layer 3 of the first-level tower mainly produces an oxidation reaction with the incoming waste gas. The mixed liquid is mainly composed of an oxidant and an alkaline solution, and the components of the waste gas are mainly ammonia, VOC, hydrogen sulfide, methyl mercaptan and methyl sulfide. The alkaline solution in the mixed liquid absorbs hydrogen sulfide, methyl mercaptan and methyl sulfide, and the oxidant in the alkaline solution is oxidized, while the ammonia and VOC in the waste gas can also be partially absorbed and oxidized.

[0048] It should also be noted that the first-level tower demisting layer 4 is arranged between the first-level tower spray layer 3 and the ozone aeration disk 5. The first-level tower demisting layer 4 can remove water from the exhaust gas. After passing through the ozone aeration disk 5, the exhaust gas can react homogeneously with the ozone discharged from the ozone aeration disk 5, that is, undergo secondary oxidation with ammonia and VOC.

[0049] The alkaline solution sprayed by the secondary tower spray layer 8 can absorb and neutralize the decomposition products of nitrogen oxides, sulfur dioxide, a small amount of carbon dioxide and other acidic waste gases in the waste gas, and absorb ammonia again, so that the harmful substances in the waste gas are decomposed and absorbed, and non-toxic and harmless gases are discharged.

[0050] It is worth noting that VOC is a volatile organic compound that participates in atmospheric photochemical reactions; PMS is peroxymonosulfate, a triple salt; such as potassium peroxymonosulfate, a white granular powder, easily soluble in water, is a very effective oxidant and disinfectant, with a very strong and effective non-chlorine oxidation ability, and its use and handling process meet safety and environmental protection requirements; the homogeneous reaction is also called "single-phase reaction", that is, a chemical reaction that only occurs in one phase (gas phase, liquid phase or solid phase), which is characterized by the absence of phase interface in the reaction system and rapid reaction.

[0051] The present invention arranges the first-level tower spray layer, the first-level tower demisting layer and the ozone aeration plate in the first-level tower in sequence along the flow direction of the waste gas; the second-level tower spray layer is arranged in the second-level tower; the air outlet of the first-level tower is connected to the air inlet of the second-level tower; the first-level tower spray layer is used to spray a mixed liquid that produces an oxidation reaction with the incoming waste gas, the ozone aeration plate is used to introduce ozone that produces a homogeneous reaction with the demisted waste gas, and the second-level tower spray layer is used to spray an alkali solution that absorbs and neutralizes the decomposition products of the waste gas. Through the above-disclosed waste gas treatment equipment, the waste gas passes through the first-stage tower spray layer. The oxidant in the alkaline solution sprayed by the first-stage tower spray layer can absorb the hydrogen sulfide, methyl mercaptan and methyl sulfide in the oxidized waste gas, and can also partially absorb and oxidize the ammonia and VOC in the waste gas. The first-stage tower demisting layer removes water from the waste gas, and the waste gas after dehydration undergoes an oxidation reaction with the ozone discharged from the ozone aeration disk. The ozone performs secondary oxidation on the ammonia and VOC in the waste gas. Finally, the alkaline solution sprayed by the second-stage tower spray layer absorbs and neutralizes the decomposition products of the waste gas, and absorbs the ammonia again, thereby achieving the decomposition and absorption of harmful substances in the waste gas and removing non-toxic and harmless gases.

[0052] Furthermore, the number of the first-level tower spray layers 3 is multiple, and the multiple first-level tower spray layers 3 are divided into multiple groups and are sequentially arranged in the first-level tower along the exhaust gas flow direction;

[0053] And / or, there are multiple secondary tower spray layers 8, and the multiple secondary tower spray layers 8 are divided into multiple groups and arranged in sequence in the secondary tower along the exhaust gas flow direction.

[0054] It should be noted that the number of the first-level tower spray layers 3 is set to be multiple, and the multiple first-level tower spray layers 3 are sequentially arranged in the first-level tower along the flow direction of the exhaust gas, so that when the exhaust gas passes through the first-level tower spray layer 3, the alkaline solution in the mixed liquid sprayed by the first-level tower spray layer 3 can fully absorb the hydrogen sulfide, methyl mercaptan and methyl sulfide, so that the oxidant in the alkaline solution can oxidize the hydrogen sulfide, methyl mercaptan and methyl sulfide, thereby avoiding incomplete oxidation of hydrogen sulfide, methyl mercaptan and methyl sulfide in the exhaust gas; and absorbing and oxidizing a large amount of ammonia and VOC in the exhaust gas.

[0055] The number of secondary tower spray layers 8 is set to be multiple, and the multiple secondary tower spray layers 8 are sequentially arranged in the secondary tower along the flow direction of the exhaust gas. When the exhaust gas passes through the secondary tower spray layer 8, the alkaline solution sprayed by the secondary tower spray layer 8 can fully absorb ammonia and VOC, and fully absorb and neutralize the decomposition products of nitrogen oxides, sulfur dioxide, a small amount of carbon dioxide and other acidic waste gases in the exhaust gas, so as to ensure that there are no toxic and harmful substances in the discharged exhaust gas.

[0056] Specifically, the spraying direction of the first-stage tower spray layer 3 and / or the second-stage tower spray layer 8 is opposite to the flow direction of the exhaust gas.

[0057] It should be noted that setting the spraying direction of the first-stage tower spray layer 3 opposite to the flow direction of the exhaust gas can make the sprayed alkaline solution contact with the exhaust gas in reverse, and the alkaline solution can better absorb ammonia, VOC, hydrogen sulfide, methyl mercaptan, methyl sulfide, etc. in the exhaust gas; setting the spraying direction of the second-stage tower spray layer 8 opposite to the flow direction of the exhaust gas can make the sprayed alkaline solution contact with the exhaust gas in reverse, and the alkaline solution can better absorb and neutralize the decomposition products of the exhaust gas, and re-absorb the ammonia and VOC.

[0058] Furthermore, the waste gas treatment equipment also includes a guide layer 6 arranged downstream of the ozone aeration plate 5.

[0059] It should be noted that, by providing the guide layer 6 , the guide layer 6 can guide the waste gas and the ozone discharged from the ozone aeration disk 5 to a certain position for homogeneous reaction, thereby preventing the ozone generated by the ozone aeration disk 5 from entering the primary tower spray layer 3 .

[0060] Furthermore, the exhaust gas treatment equipment further comprises: a secondary tower demisting layer 9;

[0061] The plurality of secondary tower demisting layers 9 are arranged downstream of the secondary tower spray layer 8 .

[0062] Furthermore, the exhaust gas treatment equipment further comprises: a primary tower circulating water tank 10 and a primary tower circulating pump 11;

[0063] The primary tower circulating water tank 10 is disposed at the bottom of the primary tower and is used to collect the mixed solution of the alkali solution and the oxidant in the primary tower;

[0064] The primary tower circulating water tank 10 is connected to the primary tower spray layer 3 through the primary tower circulating pump 11 .

[0065] It should be noted that, by arranging the primary tower circulating water tank 10 at the bottom of the primary tower, the primary tower circulating water tank 10 can collect the mixed solution of the alkali solution and the oxidant in the primary tower, so as to avoid the mixed solution of the alkali solution and the oxidant from being discharged and causing pollution to the environment;

[0066] The primary tower circulating water tank 10 is connected to the primary tower spray layer 3 through the primary tower circulating pump 11, so that the mixed liquid collected by the primary tower circulating water tank 10 can be recycled again, thereby saving the cost of reagents.

[0067] Furthermore, the exhaust gas treatment equipment further includes: a secondary tower circulating water tank 14 and a secondary tower circulating pump 15;

[0068] The secondary tower circulating water tank 14 is disposed at the bottom of the secondary tower and is used to collect the alkali solution in the secondary tower;

[0069] The secondary tower circulating water tank 14 is connected to the secondary tower demisting layer 9 through the secondary tower circulating pump 15 .

[0070] It should be noted that, by arranging the secondary tower circulating water tank 14 at the bottom of the secondary tower, the secondary tower circulating water tank 14 can collect the alkali solution in the secondary tower to avoid the discharge of the alkali solution causing pollution to the environment;

[0071] The secondary tower circulating water tank 14 is connected to the secondary tower demisting layer 9 through the secondary tower circulating pump 15, so that the alkali solution collected by the secondary tower circulating water tank 14 can be recycled again, thereby saving the cost of reagents.

[0072] Furthermore, the waste gas treatment equipment further includes: an oxidant storage tank 12, an oxidant pump 13, an alkali solution storage tank 16 and an alkali solution pump 17;

[0073] The oxidant storage tank 12 is connected to the outlet of the primary tower circulation pump 11 through the oxidant pump 13;

[0074] The alkali solution storage tank 16 is connected to the primary tower circulating water tank 10 and / or the secondary tower circulating water tank 14 through the alkali solution pump 17 .

[0075] Furthermore, the waste gas treatment equipment also includes an ozone tail gas alarm 19 arranged at the gas outlet 2 of the secondary tower.

[0076] It should be noted that an ozone tail gas alarm 19 is provided at the gas outlet 2 of the secondary tower to detect whether the discharged waste gas contains ozone. If ozone is present, the ozone aeration plate 5 can be adjusted to ensure that no ozone is discharged, thereby reducing ozone pollution to the environment.

[0077] Furthermore, the exhaust gas treatment equipment further includes an ozone generator 18 for generating ozone;

[0078] The ozone generator 18 is in communication with the ozone aeration disk 5 .

[0079] It should be noted that, by providing the ozone generator 18 , the ozone generated by the ozone generator 18 is transported to the ozone aeration disk 5 , thereby providing ozone to the ozone aeration disk 5 .

[0080] Preferably, the waste gas treatment equipment further includes a secondary tower demisting layer 9 disposed downstream of the secondary tower spray layer 8, for dehydrating the waste gas to be discharged.

[0081] Preferably, the first-stage tower demisting layer 8 and / or the second-stage tower demisting layer 9 adopt ceramic step rings and are provided with backwashing, so that long-term operation can be achieved without damage or replacement.

[0082] Preferably, the air outlet of the first tower is connected to the air inlet of the second tower through an inter-tower connecting pipe 7.

[0083] It should be noted that by providing an inter-tower connecting pipe 7 between the primary tower and the secondary tower, the reaction process of ozone on ammonia and VOC in the exhaust gas can be prolonged, thereby enabling ozone to fully oxidize ammonia and VOC in the exhaust gas.

[0084] refer to Figure 2 The present invention also provides a waste gas treatment method, which is applicable to the waste gas treatment equipment provided in the above embodiment, and the waste gas treatment method at least comprises the following steps:

[0085] S1. In a primary tower, the waste gas is contacted with a mixed liquid, wherein the mixed liquid includes an oxidant and an alkali solution;

[0086] S2, demisting the exhaust gas;

[0087] S3, introducing ozone to allow the ozone to react with the exhaust gas in a homogeneous manner;

[0088] S4. In the secondary tower, alkali solution is used to absorb and neutralize the oxidative decomposition products of the exhaust gas.

[0089] It should be noted that when the waste gas passes through the primary tower, it first contacts with the mixed liquid in the primary tower, the alkaline solution in the mixed liquid absorbs hydrogen sulfide, methyl mercaptan and methyl sulfide in the waste gas, the oxidant is oxidized, and at the same time, the ammonia and VOC in the waste gas are partially absorbed, and the waste gas is defogged through S2, and the defogged waste gas contacts with ozone to produce a homogeneous reaction, that is, ozone performs secondary oxidation of VOC and ammonia, and finally, in the secondary tower, the alkali solution is used to absorb and neutralize the oxidative decomposition products of the waste gas, which can prevent the decomposition products of the waste gas, such as nitrogen oxides, sulfur dioxide, a small amount of carbon dioxide and other acidic waste gases, from being discharged into the external environment, and at the same time, ammonia is absorbed again, thereby achieving the decomposition and absorption of harmful substances in the waste gas, and removing non-toxic and harmless gases, thereby preventing the waste gas from polluting the environment.

[0090] Further, based on the exhaust gas treatment method provided in the above embodiment, after executing S4, the following steps are further included:

[0091] The exhaust gas is demisted.

[0092] It should be noted that in step S4, alkaline solution is used to absorb and neutralize the decomposition products of the waste gas. The waste gas contains a large amount of water molecules. Therefore, the water molecules in the waste gas need to be removed before the waste gas is discharged.

[0093] Further, based on the exhaust gas treatment method provided in the above embodiment, after executing S4, the following steps are further included:

[0094] Detect whether the exhaust gas contains ozone.

[0095] It should be noted that by detecting whether ozone is contained in the exhaust gas, the amount of ozone emitted by the ozone aeration disk can be adjusted to avoid ozone emission into the external environment and causing pollution.

[0096] To understand the above solution, refer to Figure 1-Figure 3 , the scheme is further introduced below.

[0097] During the discharge, transfer and purification of sewage, polluting gases are inevitably generated, especially compound malodorous gases, which seriously affect the health of workers and the normal life of surrounding residents. The main pollutants of this type of waste gas are compound malodorous gases such as ammonia, hydrogen sulfide, methyl mercaptan, methyl sulfide, and VOC. This solution provides a waste gas treatment equipment, which is mainly for comprehensive treatment of compound malodorous gases generated by sewage stations and sewage lifting pump stations.

[0098] Working process of exhaust gas treatment equipment:

[0099] After collection, the waste gas is sent to the primary tower through the waste gas inlet 1. The waste gas is reversely contacted with the alkaline solution containing the oxidant atomized by the spray layer 3 of the three-layer primary tower of the tower body. The hydrogen sulfide, methyl mercaptan, methyl sulfide, etc. in the waste gas are absorbed by the alkali solution, and at the same time, they are oxidized by the oxidant in the alkali solution to promote the absorption reaction. The ammonia and VOC in the waste gas can also be partially absorbed and oxidized. The waste gas after the spray layer 3 of the primary tower passes through the demisting layer 4 of the primary tower to remove most of the water vapor carried in the waste gas. The demisted waste gas passes through the ozone aeration plate 5 and the guide layer 6 of the upper layer of the primary tower to achieve a homogeneous reaction between the waste gas and ozone. The evenly mixed waste gas passes through the inter-tower connecting pipe 7 to achieve secondary oxidation of ammonia and VOC that have not reacted completely in the primary tower by ozone. The oxidized waste gas enters the secondary tower, and in turn contacts the low-concentration alkaline solution atomized by the three-layer spray layer 8 of the tower body in reverse order in the secondary tower, so as to absorb and neutralize the acidic waste gas such as nitrogen oxides, sulfur dioxide, and a small amount of carbon dioxide produced by oxidation decomposition, and at the same time, the third absorption of ammonia is achieved by the property that ammonia is highly soluble in water. The purified waste gas passes through the double-layer secondary tower demisting layer 9 at the top of the secondary tower to achieve dehydration and demisting of the waste gas, and the demisted waste gas is discharged through the waste gas outlet 2 or the fan of the chimney.

[0100] The first-stage tower circulating water tank 10 contains a mixture of alkali solution and oxidant, which is connected to the first-stage tower spray layer 3 through the first-stage tower circulating pump 11 for circulation; the alkali solution is sodium hydroxide solution and the oxidant is PMS (permonosulfate); the oxidant is continuously pumped into the outlet pipe of the first-stage tower circulating pump 11 through the oxidant storage tank 12 and the oxidant dosing pump 13, and the alkali solution is added into the first-stage tower circulating water tank 10 through the alkali solution storage tank 16 and the alkali solution pump 17; the pH in the first-stage tower circulating water tank 10 is controlled between 12-12.5 to avoid self-decomposition of the oxidant while ensuring strong absorption capacity.

[0101] The exhaust gas flow rate of the inter-tower connecting pipe 7 is less than 6m / s, which ensures that the reaction time between ozone and exhaust gas is greater than 2s, thus ensuring sufficient reaction time.

[0102] The secondary tower circulating water tank 14 contains a low-concentration alkaline solution, which is connected to the secondary tower spray layer 8 for circulation through the secondary tower circulating pump 15; the alkali solution is a sodium hydroxide solution, and the alkali solution is added to the secondary tower circulating water tank 14 through the alkali solution storage tank 16 and the alkali solution pump 17; the pH in the secondary tower circulating water tank 14 is controlled between 8 and 9 to ensure the absorption capacity while achieving the third absorption of ammonia.

[0103] The ozone source of the ozone aeration plate 5 comes from the ozone generator 18. The added power of the ozone generator 18 can achieve 10%-100% output adjustment. The ozone tail gas alarm 19 is set at the secondary tower top exhaust gas outlet 2 to interlock the ozone dosage adjustment to ensure that no ozone is discharged.

[0104] The packing of the first tower demisting layer 4 and / or the second tower demisting layer 9 adopts ceramic step rings, which ensures mechanical strength and reduces the resistance of gas passing through the packing layer. Each demisting layer is equipped with a backwashing device, which does not need to be replaced if it is not damaged.

[0105] According to the pollutant properties and concentration of the waste gas from the sewage station, liquid oxidant and gas oxidant are used for combined oxidation, and a double-tower two-stage alkali solution spraying method is adopted to ensure the full oxidation and absorption of the pollutants;

[0106] The liquid oxidant is configured with PMS (permonosulfate), which is a derivative of hydrogen peroxide and is in solid powder form, which is convenient for transportation and storage. Its oxidizing property is better than that of hydrogen peroxide, and the product is relatively non-toxic and harmless. Under alkaline conditions, the stability is better through the control of H value.

[0107] The gaseous oxidant flows evenly with the exhaust gas through the ozone aeration plate 5 and the guide layer 6 at the top of the first-stage tower, and then the flow velocity of the inter-tower connecting pipe 7 is controlled to prolong the ozone oxidation time to ensure that the oxidation reaction is fully carried out; at the same time, the amount of oxidant added can be adjusted, together with the ozone tail gas alarm 19, to ensure that there is no ozone residue in the exhaust gas;

[0108] It uses empty tower spraying, and the demisting layer uses ceramic step rings and is equipped with backwashing, which can achieve long-term operation without damage or replacement;

[0109] The circulating water tank and circulating pump are used to realize the recycling of the reagents and discharge them regularly, making full use of the residual value of the reagents and saving operating costs.

[0110] Each of the two towers is equipped with a water tank, which can be adjusted according to the exhaust gas concentration and the nature of the pollutants;

[0111] Alternative solutions of the present invention:

[0112] Replace the oxidant and the demisting layer filler through similar tower structures;

[0113] The process route is applied to other industries with similar exhaust gas composition.

[0114] The key points of the present invention are: double tower structure and internal arrangement, water tank pH control, liquid oxidant selection and adding method, adjustable gas oxidant and adding position and adding method, and lengthened reaction stroke.

[0115] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0116] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0117] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A waste gas treatment device, characterized in that: Applicable to a sewage station or a sewage lifting pump station, comprising: a primary tower, a secondary tower, a primary tower spray layer (3), a primary tower demisting layer (4), an ozone aeration plate (5), an inter-tower connecting pipe (7) and a secondary tower spray layer (8); The first-stage tower spray layer (3), the first-stage tower demisting layer (4) and the ozone aeration plate (5) are sequentially arranged in the first-stage tower along the exhaust gas flow direction; It also includes a guide layer (6) arranged downstream of the ozone aeration plate (5); The secondary tower spray layer (8) is arranged in the secondary tower; The air outlet of the first tower is connected to the air inlet of the second tower via the inter-tower connecting pipe (7); The first-stage tower spray layer (3) is used to spray a mixed liquid that produces an oxidation reaction with the incoming waste gas, wherein the mixed liquid includes an oxidant and an alkaline solution. Hydrogen sulfide, methyl mercaptan, and methyl sulfide in the waste gas are absorbed by the alkaline solution and oxidized by the oxidant to promote the absorption reaction. Ammonia and VOC in the waste gas can be partially absorbed and oxidized at one time. The first-stage tower demisting layer (4) is used to remove water from the exhaust gas; The ozone aeration plate (5) and the guide layer (6) are used to introduce ozone that reacts homogeneously with the demisted exhaust gas, and the uniformly mixed exhaust gas passes through the inter-tower connecting pipe (7) to achieve secondary oxidation of ammonia and VOC that have not reacted completely in the primary tower by the ozone; The secondary tower spray layer (8) is used to spray a low-concentration alkali solution for absorbing and neutralizing the decomposition products of the waste gas, thereby achieving absorption and neutralization of the acidic waste gas. At the same time, the third absorption of ammonia is achieved through the property that ammonia is highly soluble in water, so that harmful substances in the waste gas are decomposed and absorbed, and non-toxic and harmless gas is discharged.

2. The exhaust gas treatment equipment according to claim 1, characterized in that: The first-stage tower spray layers (3) are multiple in number, and the multiple first-stage tower spray layers (3) are sequentially arranged in the first-stage tower along the exhaust gas flow direction; And / or, the number of the secondary tower spray layers (8) is multiple, and the multiple secondary tower spray layers (8) are arranged in sequence in the secondary tower along the flow direction of the exhaust gas.

3. The exhaust gas treatment equipment according to claim 1, characterized in that: The spraying direction of the first tower spray layer (3) and / or the second tower spray layer (8) is opposite to the flow direction of the exhaust gas.

4. The exhaust gas treatment equipment according to claim 1, characterized in that: Also includes: Secondary tower demisting layer (9); The plurality of secondary tower demisting layers (9) are arranged downstream of the secondary tower spray layer (8).

5. The exhaust gas treatment equipment according to claim 1, characterized in that: Also includes: A first-stage tower circulating water tank (10) and a first-stage tower circulating pump (11); The primary tower circulating water tank (10) is arranged at the bottom of the primary tower and is used to collect the mixed liquid of the alkali solution and the oxidant in the primary tower; The primary tower circulating water tank (10) is connected to the primary tower spray layer (3) via the primary tower circulating pump (11).

6. The exhaust gas treatment equipment according to claim 4, characterized in that: Also includes: A secondary tower circulating water tank (14) and a secondary tower circulating pump (15); The secondary tower circulating water tank (14) is arranged at the bottom of the secondary tower and is used to collect the alkali liquid in the secondary tower; The secondary tower circulating water tank (14) is connected to the secondary tower demisting layer (9) via the secondary tower circulating pump (15).

7. The exhaust gas treatment equipment according to claim 6, characterized in that: Also includes: An oxidant storage tank (12), an oxidant pump (13), an alkali solution storage tank (16) and an alkali solution pump (17); The oxidant storage tank (12) is connected to the outlet of the primary tower circulation pump (11) via the oxidant pump (13); The alkali solution storage tank (16) is connected to the primary tower circulating water tank (10) and / or the secondary tower circulating water tank (14) via the alkali solution pump (17).

8. The exhaust gas treatment equipment according to claim 1, characterized in that: It also includes an ozone tail gas alarm (19) arranged at the gas outlet (2) of the secondary tower.

9. A method for treating waste gas, characterized in that: The exhaust gas treatment device according to any one of claims 1 to 8 comprises the following steps: S1, contacting the waste gas with a mixed solution, wherein the mixed solution includes an oxidant and an alkali solution; S2, demisting the exhaust gas; S3, introducing ozone to allow the ozone to react with the exhaust gas in a homogeneous manner; S4. Absorbing and neutralizing the products of the oxidative decomposition of the exhaust gas.

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