A method and device for treating VOCs gas using flue gas

Abstract

The present invention provides a method and device for treating VOCs gas by using flue gas, the method comprising the following steps: mixing cupola flue gas and incinerator flue gas at a volume ratio of 1: (1.8-3) for reaction, adding a desulfurizer after the reaction to continue the reaction, the desulfurizer is preferably an inorganic base. The method for treating VOCs gas of the present invention makes SO2, NO in cupola flue gas X The components such as HCHO, C6H5-OH, CH4 and other components in the incinerator flue gas react with each other, and after the reaction is complete, pollution-free products are generated respectively. The treatment method simultaneously achieves the scientific treatment of VOCs gas and nitrogen-containing and sulfur-containing toxic gases. In addition, the method has low operating cost, simple operation, good treatment effect, and can generate products with high added value for recycling.

Description

Technical Field

[0001] The present invention relates to the field of flue gas treatment in the thermal insulation material industry, and in particular to a method and device for treating VOCs gas by utilizing flue gas. Background Art

[0002] The flue gas emissions of the insulation material industry are mainly composed of two parts: one is the flue gas from the cupola for melting ore, and the other is the flue gas from the incinerator of the insulation material curing production line and the cotton collection production line. The chemical composition of the flue gas from these two parts is different. The components of the flue gas from the cupola for melting ore are mainly smoke particles, sulfur dioxide, and nitrogen oxides. The main chemical components of the flue gas from the incinerator of the insulation material curing production line and the cotton collection production line are formaldehyde, phenol, and total methane hydrocarbons (VOCs).

[0003] In the existing technology, the cupola flue gas treatment mainly adopts bag dust removal, desulfurization tower, SCRS and NCR methods. The main methods for treating incinerator flue gas are: 1. Condensation recovery method: the VOCs produced by industrial production are directly introduced into the condenser, and the exhaust gas meets the emission standards through the action and reaction of adsorption, absorption, analysis, separation and other links. 2. Physical absorption method: the exhaust gas is introduced into the absorption liquid for absorption and purification, and the absorption liquid is heated, analyzed, condensed and other treatments after saturation. 3. Direct combustion method: the exhaust gas is ignited by auxiliary materials such as fuel gas, so that the harmful substances therein are converted into harmless substances under high temperature combustion. 4. Catalytic combustion method: the exhaust gas is heated and converted into harmless carbon dioxide and water after catalytic combustion. 5. Adsorption method: the organic exhaust gas is adsorbed and purified by activated carbon. High investment, high energy consumption, large equipment volume and long construction period.

[0004] It can be seen that the above-mentioned treatment methods all have problems such as high energy consumption, high investment, great difficulty in processing, and high operating costs.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first object of the present invention is to provide a method for treating VOCs gas by using flue gas, wherein the method comprises mixing the cupola flue gas with the incinerator flue gas to react the SO2 and NO in the cupola flue gas. X The components react with HCHO, C6H5-OH, CH4 and other components in the incinerator flue gas, and after the reaction is complete, pollution-free products are generated respectively. This treatment method simultaneously achieves the scientific treatment of VOCs gas and nitrogen-containing and sulfur-containing toxic gases. In addition, the method has low operating cost, simple operation, good treatment effect, and can generate products with high added value for recycling.

[0007] The second purpose of the present invention is to provide a treatment equipment using the above-mentioned treatment method. The equipment has a simple structure, low cost, and small footprint. The equipment can achieve efficient and harmless treatment of VOCs gas. The generated products only require simple solid waste treatment, without the introduction of too much treatment equipment, and are green and environmentally friendly.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] The present invention provides a method for treating VOCs gas by utilizing flue gas, comprising the following steps:

[0010] The cupola flue gas and the incinerator flue gas are mixed and reacted in a volume ratio of 1: (1.8-3), and a desulfurizing agent is added after the reaction to continue the reaction. The desulfurizing agent is preferably an inorganic base.

[0011] In the prior art, cupola flue gas and incinerator flue gas are generally treated harmlessly separately, but there are problems such as high treatment cost, great treatment difficulty, and incomplete treatment.

[0012] In order to solve the above technical problems, the present invention utilizes the characteristic that two flue gas components can be mixed to undergo chemical reactions, so that the two flue gases can be treated at one time, which not only reduces the difficulty of the treatment operation, but also greatly reduces the treatment cost. In order to ensure that the two flue gases fully react and are thoroughly treated, a lot of practical exploration has been carried out on the volume ratio of the two flue gases. It was found that the cupola flue gas and the incinerator flue gas need to react in a volume ratio of 1: (1.8-3). Preferably, the volume ratio of the cupola flue gas to the incinerator flue gas is 1: (1.9-2.5), and more preferably the volume ratio is 1:2.

[0013] In addition, the volume ratio of the cupola flue gas to the incinerator flue gas can also be 1:2.2, 1:2.3, 1:2.4, 1:2.6, 1:2.7, 1:2.8, 1:2.9, etc.

[0014] Preferably, as a further feasible solution, the desulfurizer is at least one of sodium hydroxide, potassium hydroxide and magnesium hydroxide, preferably sodium hydroxide, which is cheap and easily available and has a good desulfurization effect.

[0015] Preferably, as a further implementable solution, the flow rates of the cupola flue gas and the incinerator flue gas are both controlled between 1-15 m / s, preferably between 3-7.5 m / s, and the flow rates of the two flue gases are sufficiently reduced, so that the mixing reaction of the two flue gases can be more thorough. In actual operation, different flow rates can be used in different reaction stages, so that the flow rates of the two flue gases tend to gradually decrease, and the reaction is gradually promoted.

[0016] In addition, the flow rate of the two flue gases can also be 2m / s, 4m / s, 5m / s, 6m / s, 8m / s, 10m / s, 11m / s, 12m / s, 13m / s and so on.

[0017] Preferably, as a further implementable scheme, the desulfurizer is formulated into an aqueous solution with a mass percentage concentration of 30-80%, preferably a desulfurizer aqueous solution with a mass percentage concentration of 75%. The mass concentration of the sodium hydroxide solution cannot be too low, otherwise the subsequent treatment will not be thorough. Of course, the concentration of the sodium hydroxide solution cannot be too high, so as not to affect the uniformity of the gas-liquid mixing reaction after it contacts the flue gas.

[0018] The specific chemical reaction principles of the two types of flue gas are as follows:

[0019] In VOCs gas, formaldehyde absorbs sulfur dioxide to generate hydroxymethanesulfonic acid (an intermediate for producing pharmaceutical arsenic sulfonate and sodium isoniazid sulfonate, and electroplating additives). Its chemical formula is:

[0020] SO2+H2O+HCHO=CH4SO4

[0021] If the subsequent treatment is incomplete, a desulfurizer will be added to continue the treatment. Formaldehyde and the desulfurizer (sodium hydroxide) undergo a disproportionation reaction to generate methanol CH3OH and sodium formate HCOONa. The generated sodium benzoate is also a valuable product and can be used as a preservative for pharmaceuticals. Its chemical formula is:

[0022] 2HCHO+NaOH=HCOONa+CH3OH

[0023] In VOCs gas, phenol is removed by the following method: sodium phenol reacts with sulfur dioxide to produce carbolic acid (acid) and sodium sulfite (for making cellulose sulfite, organic chemicals, bleaching fabrics, etc., and also used as a reducing agent, preservative, and dechlorinating agent):

[0024] SO2+H2O+2C6H5ONa=2C6H5OH+Na2SO3

[0025] If the treatment is not complete, desulfurizer will be added to continue the treatment. The reaction equation of phenol and desulfurizer (sodium hydroxide) is as follows:

[0026] C6H5OH+NaOH=C6H5ONa+H2O

[0027] In VOCs gas, methane is removed by the following method. The reaction equation of total methane hydrocarbons and sulfur dioxide is as follows: CH4+SO2=CO2+2H2+S

[0028] Methane and nitric oxide undergo a redox reaction, and the specific reaction equation is as follows:

[0029] 4NO+CH4=2N2+CO2+2H2O

[0030] The specific equation for the reaction between methane and nitrogen dioxide is as follows:

[0031] CH4+4NO2═4NO+CO2+2H2O

[0032] In summary, by adopting the above reaction principle, it can be seen that the two flue gases can be mixed and reacted to achieve harmless treatment of most of the flue gases. If the treatment is incomplete, it can react with the added desulfurizer to continue the harmless treatment. The entire treatment method ultimately achieves complete treatment of all flue gases.

[0033] In addition to providing a method for treating VOCs gas, the present invention also provides a complete set of VOCs gas treatment equipment, including: a pre-reaction tank, a gas catcher and a desulfurization reaction tank connected in sequence, wherein a desulfurization agent spraying device is provided on the top of the desulfurization reaction tank;

[0034] The cupola flue gas and the incinerator flue gas enter the pre-reaction tank at a volume ratio of 1:(1.8-3) for reaction, and then further react in the gas capture device, and finally react with the desulfurizer in the desulfurization reaction tank.

[0035] The VOCs gas treatment equipment of the present invention has a simple structure and only needs three simple devices to fully treat the flue gas. The desulfurizer spraying device in the desulfurization reaction tank is preferably a spray head. The desulfurizer aqueous solution sprayed by the spray head mixes with the flue gas to react and absorb the flue gas.

[0036] Preferably, as a further implementable solution, the top of the pre-reaction tank is connected to a cupola flue gas duct and an incinerator flue gas duct arranged side by side, and the diameter of the incinerator flue gas duct is twice the diameter of the cupola flue gas duct.

[0037] Preferably, as a further feasible solution, a plurality of layers of grid plates are arranged in the gas capture device, and the grid plates are provided to reduce the flow rate of the flue gas, increase the contact area between the flue gases, and improve the treatment effect.

[0038] Preferably, as a further feasible solution, the top of the desulfurization reaction tank is connected with an induced draft fan for promoting the flow of flue gas in the desulfurization reaction tank.

[0039] Preferably, as a further implementable solution, a material outlet is provided at the bottom of the desulfurization reaction tank, and the material outlet is connected to a filter press. Preferably, a delivery pump is provided between the material outlet and the filter press.

[0040] The flue gas from the cupola desulfurization, denitrification and dust removal enters the pre-reaction tank for mixed reaction with the VOCs flue gas at the same time, making the SO2, NO X React with the incinerator flue gas HCHO, C6H5-OH, and CH4 to generate pollution-free substances. The flue gas that has not completely reacted enters the gas capture device and the desulfurization reaction tank in turn to continue to react and generate pollution-free substances. These pollution-free substances enter the filter press through the material outlet for water and sewage separation. It is preferably pumped into the filter press through a feed pump for water and sewage separation to achieve the removal of TSP, SO2, NO X , HCHO, C6H5-OH, CH4 flue gas pollutants.

[0041] In summary, the removal process of formaldehyde, phenol and methane total hydrocarbon VOCs and the specific design of VOCs removal equipment are described as follows:

[0042] A cupola flue gas duct and an incinerator flue gas duct are arranged side by side at the top inlet of the pre-reaction tank, so that the cupola flue gas and the incineration and curing furnace flue gas enter the pre-reaction tank and are fully mixed to generate a chemical reaction. Sulfur dioxide reacts with formaldehyde, phenol and total methane hydrocarbons to generate hydroxymethanesulfonic acid, carbolic acid (acid) and sodium sulfite, and carbon dioxide, nitrogen, nitric oxide, nitrogen dioxide and total methane hydrocarbons to generate nitrogen and water.

[0043] Then, the formaldehyde and phenol flue gas that have not been completely removed enter the desulfurization reaction tank and react with the desulfurizer sodium hydroxide to produce methanol CH3OH and sodium formate HCOONa and sodium phenol C6H5-ONa. These substances enter the filter press together with the sewage for water and sewage separation to achieve the purpose of removal!

[0044] Preferably, the cross-sectional area of ​​the pre-reaction tank = 2 (cross-sectional area of ​​the cupola flue gas pipeline + cross-sectional area of ​​the incinerator flue gas pipeline), so that the flow rate of the flue gas after mixing can be reduced by half, so as to achieve full mixing and full reaction. The flue gas can fall vertically to the bottom of the pre-reaction tank due to the centrifugal force of the induced draft fan and the gravity of the flue gas. The pre-reaction tank is connected to the upper part of the gas capture device. When the flue gas passes through the pre-reaction tank and enters the gas capture device, it is fully mixed to achieve the gas phase of the flue gas and VOC S Gas phase chemical reaction. At the beginning, the flow rate of the two flue gases is controlled at 15m / s. After entering the pre-reaction tank, the cross-sectional area of ​​the pre-reaction tank is twice the sum of the cross-sectional areas of the two pipes. The flue gas flow rate is reduced to 7.5m / s, and the flue gas is fully mixed. After entering the gas capture device, the flow rate is reduced to 3m / s, which can react more fully. The unreacted flue gas enters the desulfurization reaction tank to react with sodium hydroxide, and the formaldehyde and phenol are removed for the second time, which can basically achieve 100% removal of harmful substances in the flue gas. Finally, the treated flue gas is discharged from the bottom of the desulfurization reaction tank.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The present invention uses flue gas to treat VOC S The gas method is to mix the cupola flue gas with the incinerator flue gas to react, so that SO2 and NO in the cupola flue gas are X The components react with HCHO, C6H5-OH, CH4 and other components in the flue gas of the incinerator, and after the reaction is complete, pollution-free products are generated respectively. The method is simple and the cost is low;

[0047] (2) The treatment method of the present invention achieves scientific treatment of VOCs gas and nitrogen- and sulfur-containing toxic gases, has strong operability, and can be industrialized;

[0048] (3) VOC of the present invention S The gas treatment equipment has a simple structure, produces less waste, achieves full reaction treatment of flue gas, occupies a small area, and is environmentally friendly;

[0049] (4) VOC of the present invention S The gas treatment equipment can achieve 100% treatment of cupola flue gas and incinerator flue gas, without the need to add too much additional treatment equipment, which simplifies the operation steps and reduces the operation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0051] Figure 1 A schematic diagram of the structure of a treatment device for treating VOCs gas using flue gas provided in an embodiment of the present invention. Description of the drawings:

[0053] 10-pre-reaction tank; 101-cupola flue gas duct;

[0054] 102-incinerator flue gas duct; 20-gas capture device;

[0055] 201-grid plate; 30-desulfurization reaction tank;

[0056] 301- desulfurization agent spraying device; 302- material outlet;

[0057] 40-filter press; 50-transport pump;

[0058] 60- induced draft fan. DETAILED DESCRIPTION

[0059] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0060] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0061] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In order to more clearly explain the technical solution of the present invention, it is described in the form of specific embodiments below.

[0063] Example

[0064] See also Figure 1As shown, a cupola flue gas duct 101 and an incinerator flue gas duct 102 are arranged side by side at the top inlet of the pre-reaction tank 10, and the diameter of the incinerator flue gas duct 102 is twice the diameter of the cupola flue gas duct 101, and the two ducts extend into the interior of the pre-reaction tank 10 at the same time, so that the cupola flue gas and the incineration and curing furnace flue gas enter the pre-reaction tank 10 at a volume ratio of 1:2 to be fully mixed and chemically reacted, sulfur dioxide reacts with formaldehyde, phenol and total methane hydrocarbons respectively, and hydroxymethanesulfonic acid, carbolic acid (acid) and sodium sulfite and carbon dioxide, nitrogen, nitric oxide, nitrogen dioxide and total methane hydrocarbons generate nitrogen and water respectively, and the cross-sectional area of ​​the pre-reaction tank 10 is twice the sum of the cross-sectional areas of the cupola flue gas duct 101 and the incinerator flue gas duct 102.

[0065] Initially, the flow rate of the cupola flue gas in the cupola flue gas duct 101 is controlled at 15 m / s, and the flow rate of the incinerator flue gas in the incinerator flue gas duct 102 is also controlled at 15 m / s. After both flue gases enter the pre-reaction tank 10, the flue gas flow rate is reduced to 7.5 m / s, and the two flue gases are fully mixed. Generally speaking, the cross-sectional area of ​​the pre-reaction tank 10 = 2 (cross-sectional area of ​​the cupola flue gas duct 101 + cross-sectional area of ​​the incinerator flue gas duct 102), so that the flow rate of the flue gases after mixing can be reduced by half, so as to achieve full mixing and full reaction.

[0066] The pre-reaction tank 10 is preferably provided with an induced draft fan 60, so that the flue gas can fall vertically into the bottom of the pre-reaction tank 10 due to the centrifugal force of the induced draft fan 60 and the gravity of the flue gas. The pre-reaction tank 10 is connected to the upper part of the gas capture device 20. When the flue gas passes through the pre-reaction tank 10 and enters the gas capture device 20, it is fully mixed to achieve the separation of the flue gas phase and the VOC. S Gas phase chemical reaction. In order to reduce the flow rate of the flue gas, a plurality of grid plates 201 are vertically arranged in the gas capturer 20. The flow rate of the flue gas in the gas capturer 20 is 3 m / s.

[0067] Then, the formaldehyde and phenol flue gas that are not completely removed enter the desulfurization reaction tank 30 and react with the desulfurizer sodium hydroxide to generate methanol CH3OH and sodium formate HCOONa, sodium phenol C6H5-ONa. These substances enter the filter press 40 together with the sewage from the material outlet 302 at the bottom of the desulfurization reaction tank 30 to separate the water and sewage, thereby achieving the purpose of removal. A desulfurizer spraying device 301 is provided at the top of the desulfurization reaction tank 30. The desulfurizer spraying device 301 is a spray head structure. The desulfurizer sodium hydroxide is prepared into an aqueous solution with a mass percentage concentration of 75wt%, which is sprayed by the spray head and is in reverse contact with the flue gas for absorption.

[0068] An induced draft fan 60 for promoting the flow of flue gas in the desulfurization reaction tank 30 is arranged on the top of the desulfurization reaction tank 30 , and a delivery pump 50 is also arranged between the material outlet 302 and the filter press 40 .

[0069] In the above embodiment, the volume ratio of the cupola flue gas to the incinerator flue gas can also be 1:1.8, 1:1.9, 1:2.5, etc.

[0070] In the above embodiment, the desulfurizing agent may be potassium hydroxide, or a mixture of sodium hydroxide and potassium hydroxide, in addition to sodium hydroxide. The mass percentage concentration of the desulfurizing agent aqueous solution may also be 30%, 80%, etc.

[0071] In the above embodiment, the flow velocity of the flue gas in the gas capture device 20 may also be 1 m / s.

[0072] Application Examples

[0073] Ultra-low design parameters: cupola flue gas flow rate 20,000 m 3 / h; smoke particulate matter concentration 2000mg / m 3 、Flue gas nitrogen oxide concentration 500mg / m 3 、Sulphur dioxide concentration in flue gas: 1110mg / m 3 .

[0074] The flue gas flow rate of cotton collection and solidification incinerator is 40,000 m 3 / h, flue gas formaldehyde 3.03mg / m 3 ; Phenol in flue gas 2.12mg / m 3 ; Total methane in flue gas 5.15mg / m 3 .

[0075] The exhaust gas parameters are as follows:

[0076] Rated energy consumption of cupola:

[0077] 1.2 million m 3 / a Natural gas; coke 12000T / a; electricity 9.05 million kwh / a; fresh water 18327T / a

[0078] Cupola flue gas volume 20000 + incinerator flue gas volume 4000Nm 3 / h(standard condition)

[0079] Quantity: cupola, cotton collection production line, curing production line

[0080] Mode of operation: All year round.

[0081] VOC Removal S It requires sulfur dioxide from flue gas and is a rich chemical reaction.

[0082] 22.22 kg of sulfur dioxide is generated per hour, and 1.02 kg of sulfur dioxide is used, which is a rich reaction.

[0083] 10kg of nitrogen oxides are generated per hour and 0.74kg of nitrogen oxides are used. It is a rich reaction. The specific ratios between the materials to be treated are shown in Table 1-4 below.

[0084] Table 1 Pollutant flow

[0085] Pollutant Name <![CDATA[Flue gas flow rate m 3 / h]]> <![CDATA[Concentration mg / m 3 > kg / h Use sulfur dioxide ratio <![CDATA[SO2(kg)]]> Sulfur dioxide production per hour 20000 1111 22.22 Formaldehyde generation per hour 40000 3.03 0.1212 2.00 0.242 Phenol production per hour 40000 2.12 0.0848 0.37 0.031 Methane production per hour 40000 5.15 0.2060 3.60 0.742 Total mass of VOCS kg / h 0.4120 1.015 Pollutant Name <![CDATA[Flue gas flow rate m 3 / h]]> <![CDATA[Concentration mg / m 3 > kg / h Use of nitrogen oxides kg / h Nitrogen oxides generated per hour 20000 500 10 Methane production per hour 40000 5.15 0.2 3.60 0.7416

[0086] Table 2 Desulfurization agent required

[0087] Pollutant Name <![CDATA[Flue gas flow rate m 3 / h]]> <![CDATA[Concentration mg / m 3 > kg / h Use sodium hydroxide multiples NaOH(kg) Formaldehyde generation per hour 40000 3.03 0.1212 1.09 0.1321 Phenol production per hour 40000 2.12 0.0848 0.42 0.0356 Total(kg) 0.1677

[0088] Table 3 Desulfurization agent usage for removing VOCs

[0089] Pollutants Pollutant mass kg / h Use sulfur dioxide kg / h Use of sodium hydroxide kg / h Formaldehyde removal 0.12 0.07 0.08 Removal of phenol 0.08 0.03 0.08 Removal of total methane hydrocarbons 0.2 0.05 total 0.4 0.15 0.16 Removal of total methane hydrocarbons Use of nitrogen oxides kg / h total 0.2 1

[0090] Table 4 Desulfurization agent usage for removing sulfur dioxide

[0091] Pollutant Name <![CDATA[Flue gas flow rate m 3 / h]]> <![CDATA[Concentration mg / m 3 > <![CDATA[SO2,kg / h]]> Use sodium hydroxide mass kg Sulfur dioxide production per hour 20000 1111 22.22 33.3 Total amount of sodium hydroxide used 33.5

[0092] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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.

Claims

1. A method for treating VOCs gas using flue gas, characterized in that: The steps include: Mix the flue gas from the cupola of molten ore or the flue gas from the incinerator of the heat preservation material solidification production line or the cotton collection production line with the flue gas from the incinerator whose main chemical components are formaldehyde, phenol and methane total hydrocarbons in a volume ratio of 1: (1.8-3) for reaction, and add a desulfurizer to continue the reaction after the reaction; In VOCs gas, formaldehyde absorbs sulfur dioxide to generate hydroxymethanesulfonic acid, and its chemical formula is: SO2+H2O+HCHO=CH4SO4; If the subsequent treatment is not complete, a desulfurizer will be added to continue the treatment. Formaldehyde and the desulfurizer undergo a disproportionation reaction to generate methanol CH3OH and sodium formate HCOONa. The generated sodium benzoate is also a valuable product and can be used as a preservative for pharmaceuticals. Its chemical formula is: 2HCHO+NaOH=HCOONa+CH3OH; In VOCs gas, phenol is removed by the following method: sodium phenol reacts with sulfur dioxide to produce carbolic acid and sodium sulfite: SO2+H2O+2C6H5ONa=2C6H5OH+Na2SO3; If the treatment is not complete, desulfurizer will be added to continue the treatment. The reaction equation of phenol and desulfurizer is as follows: C6H5OH+NaOH=C6H5ONa+H2O; In VOCs gas, methane is removed by the following method. The reaction equation of total methane hydrocarbons and sulfur dioxide is as follows: CH4+SO2=CO2+2H2+S; Methane and nitric oxide undergo a redox reaction, and the specific reaction equation is as follows: 4NO+CH4=2N2+CO2+2H2O; The specific equation for the reaction between methane and nitrogen dioxide is as follows: CH4+4NO2=4NO+CO2+2H2O; The desulfurizing agent is sodium hydroxide.

2. The method for treating VOCs gas by using flue gas according to claim 1, characterized in that: The volume ratio of the cupola flue gas for melting ore or the incinerator flue gas of the thermal insulation material solidification production line and the cotton collection production line to the incinerator flue gas whose main chemical components are formaldehyde, phenol and methane total hydrocarbons is 1: (1.9-2.5).

3. The method for treating VOCs gas by using flue gas according to claim 2, characterized in that: The volume ratio of the cupola flue gas for melting ore or the incinerator flue gas of the thermal insulation material solidification production line and the cotton collection production line to the incinerator flue gas whose main chemical components are formaldehyde, phenol and methane total hydrocarbons is 1:

2.

4. The method for treating VOCs gas by using flue gas according to claim 1, characterized in that: The desulfurizing agent is at least one of sodium hydroxide, magnesium hydroxide and potassium hydroxide.

5. The method for treating VOCs gas by using flue gas according to any one of claims 1 to 4, characterized in that: The flow rates of the cupola flue gas for melting ore, the incinerator flue gas of the thermal insulation material solidification production line or the cotton collection production line, and the incinerator flue gas whose main chemical components are formaldehyde, phenol, and methane total hydrocarbons are all controlled between 1-15m / s.

6. The method for treating VOCs gas by using flue gas according to claim 5, characterized in that: The flow rate of the cupola flue gas for melting ore, the incinerator flue gas of the insulation material curing production line or the cotton collection production line, and the incinerator flue gas whose main chemical components are formaldehyde, phenol, and methane total hydrocarbons are all controlled between 3-7.5m / s.

7. The method for treating VOCs gas by using flue gas according to any one of claims 1 to 2, characterized in that: The desulfurizing agent is prepared into an aqueous solution with a mass percentage concentration of 30-80%.

8. The method for treating VOCs gas by using flue gas according to claim 7, characterized in that: The desulfurizing agent is prepared into a desulfurizing agent aqueous solution with a mass percentage concentration of 75%.

9. A device for treating VOCs gas using the method for treating VOCs gas according to claim 5, characterized in that: include: A pre-reaction tank, a gas capture device and a desulfurization reaction tank are connected in sequence, and a desulfurization agent spraying device is arranged on the top of the desulfurization reaction tank; The cupola flue gas for melting ore or the incinerator flue gas of the insulation material solidification production line or the cotton collection production line and the incinerator flue gas whose main chemical components are formaldehyde, phenol and methane total hydrocarbon enter the pre-reaction tank at a volume ratio of 1: (1.8-3) for reaction, and then further react in the gas capture device, and finally react with the desulfurizer in the desulfurization reaction tank; The top of the pre-reaction tank is connected to a cupola flue gas duct and an incinerator flue gas duct arranged side by side, and the diameter of the incinerator flue gas duct is twice the diameter of the cupola flue gas duct; A material outlet is provided at the bottom of the desulfurization reaction tank, and the material outlet is connected to a filter press.

10. The device for treating VOCs gas according to claim 9, characterized in that: A delivery pump is arranged between the material outlet and the filter press.

11. The device for treating VOCs gas according to claim 9, characterized in that: The gas catcher is provided with multiple layers of grid plates.

12. The device for treating VOCs gas according to claim 9, characterized in that: The top of the desulfurization reaction tank is connected with an induced draft fan for promoting the flow of flue gas in the desulfurization reaction tank.

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