Method and device for treating straw steam explosion waste gas

Abstract

The invention relates to a method and a device for treating steam explosion waste gas of straws, which are characterized in that the steam explosion waste gas is conveyed to a washing tower, steam, acid mist and part of organic pollutants in the waste gas are captured by using a detergent, and the washed gas flow enters a catalytic oxidation unit; tower bottom liquid of the washing tower enters a desorption tower for gas stripping, and generated gas flow is fed into a catalytic oxidation unit; the catalytic oxidation unit mainly comprises a catalytic oxidation reactor filled with a water-resistant catalytic oxidation catalyst. According to the characteristics of the straw steam explosion waste gas, a combined process of washing, gas stripping desorption and catalytic oxidation is adopted, organic pollutants in the waste gas can be efficiently removed, long-term stable operation of the device can be maintained, and adverse effects of acid mist and steam are avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of air pollution control, and particularly relates to a method and device for treating straw explosion-expanded waste gas. Background Art

[0002] The main utilization path of lignocellulosic raw materials is to hydrolyze hemicellulose or / and cellulose to produce hydrolyzed sugars. The hydrolyzed sugars are fermented to produce bioenergy products such as ethanol and butanol, or / and lactic acid, citric acid, succinic acid, etc. The process of preparing hydrolyzed sugars from lignocellulosic raw materials mainly includes two steps: pretreatment and enzymatic hydrolysis. The most commonly used method for raw material pretreatment is steam explosion or dilute acid explosion pretreatment. In addition to generating hydrolyzed sugars such as xylose and glucose, a series of substances that inhibit cellulase hydrolysis and microbial fermentation are also generated. Some of these substances are volatile substances, and the steam ejected by steam explosion will be discharged into the air, causing environmental pollution.

[0003] Currently, dilute acid explosion pretreatment is more widely used. It is found that during the dilute acid explosion process, due to the acidic and high-temperature conditions, aldehyde substances such as furfural, by-products generated by the further degradation of xylose, and 5-hydroxymethylfurfural, by-products generated by the further degradation of glucose under high-temperature conditions, as well as esters and aldehyde organic substances are generated. These substances will be discharged into the air with the steam ejected by steam explosion, generating waste gas with a high water vapor content, which is difficult to remove.

[0004] CN111349659A discloses a pretreatment method for lignocellulosic raw materials, which is to mix the crushed lignocellulosic raw materials with water, continuously convey them into a conical screw device for continuous rubbing, impregnation, cooking, extrusion and dehydration, and then enter an equal-diameter screw device for secondary cooking. The raw materials move to the discharge port under the action of screw thrust for steam explosion. After explosion, the materials enter a cyclone separator. The steam ejected by steam explosion is quickly collected and pressurized by a compressor, and the pressurized steam replaces the original fresh steam and enters the first-stage cooker, so as to realize the pretreatment of lignocellulosic raw materials through such a cycle. This method can strengthen the detoxification effect of the first-stage cooking process, enhance the pretreatment effect of the materials, and can avoid the steam ejected by steam explosion being discharged into the air, causing air pollution and heat source waste. However, with the cyclic operation of the explosion-expanded waste gas, the pollutant concentration will continuously accumulate and increase, affecting the subsequent enzymatic hydrolysis of straw and the fermentation effect of sugar solution.

[0005] The catalytic oxidation (combustion) method is an efficient VOCs treatment technology. In addition to factors such as reaction temperature and space velocity, the water vapor content in the waste gas also has a significant impact on the performance of the catalyst. On the one hand, when the water vapor content in the waste gas is relatively high, the water resistance of conventional catalysts is limited. For catalysts with poor water resistance, long-term operation under such conditions will seriously shorten the service life of the catalyst. On the other hand, although the condensation method can be used to condense water vapor, organic pollutants will also enter the condensed water, generating new polluted wastewater.

[0006] CN106466606A discloses an organic waste gas catalytic combustion catalyst resistant to water vapor and sulfur poisoning and its preparation method. The catalytic combustion catalyst is composed of the following components by mass percentage: TiO2 70-93%, SiO2 3-10%, CeO2 3-10%, and CuO 1-10%. The preparation method of the catalyst is as follows: Mix metatitanic acid, the precursor of SiO2, and the precursor of CeO2 evenly by stirring, dry at 100-150°C for 8-12 hours, and calcine at 400-600°C for 3-5 hours to obtain the catalyst support; after grinding the support into powder, impregnate it in the precursor solution of CuO, and then dry at 100-150°C for 8-12 hours and calcine at 400-600°C for 3-5 hours to obtain the organic waste gas catalytic combustion catalyst resistant to water vapor and sulfur poisoning. However, the actual application effects of the prepared catalyst in resisting water vapor and sulfur poisoning are not provided in this invention. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the present invention provides a treatment method and device for straw steaming and explosion waste gas. In view of the characteristics of straw steaming and explosion waste gas, the present invention adopts a combined process of washing, stripping and desorption, and catalytic oxidation, which can not only efficiently remove organic pollutants in the waste gas, but also maintain the long-term stable operation of the device and avoid the adverse effects of acid mist and steam.

[0008] The first aspect of the present invention provides a treatment method for straw steaming and explosion waste gas, including the following steps:

[0009] (1) Transport the steaming and explosion waste gas to a washing tower, use a detergent to capture steam, acid mist and part of the organic pollutants in the waste gas, and the washed gas flow enters the catalytic oxidation unit;

[0010] (2) The bottom liquid of the washing tower enters the desorption tower for stripping, and the generated gas flow is sent to the catalytic oxidation unit for treatment;

[0011] (3) The catalytic oxidation unit mainly includes a catalytic oxidation reactor filled with a water-resistant catalytic oxidation catalyst.

[0012] In the present invention, in step (1), water is used as the detergent in the scrubbing tower, and the amount of water used is such that the liquid-gas ratio is 3 - 50 L / m 3 . The scrubbing tower can be a packed tower or a spray tower, and the packing can be any one or a mixture of several types such as Pall rings, cascade rings, and Intalox saddles made of ceramics, plastics, etc.

[0013] In the present invention, in step (1), the straw explosion waste gas enters the scrubbing tower from bottom to top and contacts the detergent countercurrently. The temperature of the detergent is controlled at 40 - 90 °C, preferably 50 - 80 °C. The scrubbing liquid generated by scrubbing is discharged regularly and can be recycled for the preparation of dilute acid for straw explosion.

[0014] In the present invention, in step (2), the desorption tower can be a packed tower or a spray tower, and the liquid-gas ratio is 1 - 10 L / m 3 , and the packing used can be any one or a mixture of several types such as Pall rings, cascade rings, and Intalox saddles made of ceramics, plastics, etc.

[0015] In the present invention, in step (2), air is generally used for stripping, and preferably a part of the purified gas discharged from the catalytic oxidation unit is used for stripping. The temperature of the gas entering the desorption tower is controlled at 50 - 95 °C, preferably 60 - 85 °C.

[0016] In the present invention, in step (2), the liquid phase after scrubbing enters from the upper part of the desorption tower. After stripping in the desorption tower, the generated gas stream enters the catalytic oxidation unit for treatment. The bottom liquid of the desorption tower enters the cooler and is recycled as the detergent after cooling.

[0017] In the present invention, in step (3), the catalytic oxidation unit further includes a conveying system and a heating system. The conveying system mainly includes a circulating fan for conveying the waste gas; the heating system mainly includes a heat exchanger or / and a heater for heating the waste gas to the temperature required for catalytic oxidation.

[0018] In the present invention, in step (3), the water-resistant catalytic oxidation catalyst preferably uses the water-resistant catalyst provided by the present invention. This catalyst is a monolithic catalyst with a honeycomb carrier as the matrix, a modified TS-1 molecular sieve as the carrier coating, and a noble metal as the active metal. Based on the monolithic catalyst, the content of the modified TS-1 molecular sieve coating is 3% - 8%, and the content of the active metal is 0.05% - 0.2%. Among them, the mesh number of the honeycomb carrier is 200 - 400 mesh, and a cordierite honeycomb ceramic carrier is preferred; the active metal is Pt, and preferably also includes one or several of Pd, Au, and Ir. The content of one or several mixtures of Pd, Au, and Ir is 0.1 - 0.5 times the content of Pt. The modification method of the modified TS-1 molecular sieve is: mixing TS-1 molecular sieve, tetrachlorosilane, and acetone, refluxing and reacting at 70 - 80 °C, and obtaining the modified TS-1 molecular sieve through filtration, washing, and drying.

[0019] The preparation method of the water-resistant catalytic oxidation catalyst described in the present invention is as follows:

[0020] (1) Mix TS-1 molecular sieve, tetrachlorosilane, and acetone, and reflux at 70-80 °C. After filtration, washing, and drying, modified TS-1 molecular sieve is obtained.

[0021] (2) Mix the modified TS-1 molecular sieve with a binder, a dispersant, and water in proportion to obtain a slurry. Immerse the honeycomb carrier in the slurry of step (1), and after purging, drying, and calcining, a coated carrier is obtained.

[0022] (3) Immerse the coated carrier in the active metal solution, and after purging, drying, and calcining, a monolithic catalyst is obtained.

[0023] In the catalyst preparation method of the present invention, the specific surface area of the TS-1 molecular sieve in step (1) is 400-450 m 2 / g, and the pore volume is 0.39-0.41 cm 3 / g. The TS-1 molecular sieve can be prepared by hydrothermal synthesis or obtained by commercial purchase.

[0024] In the catalyst preparation method of the present invention, the TS-1 molecular sieve, tetrachlorosilane, and acetone in step (1) are mixed in a mass ratio of 1:20-30:10-20. After mixing, reflux at 70-80 °C for 6-10 h. After the reaction, filter, wash with ethanol until no chloride ions are detected, and dry at 100-120 °C for 2-5 h to obtain the modified TS-1 molecular sieve.

[0025] In the catalyst preparation method of the present invention, the binder in step (2) is at least one of methyl cellulose, hydroxypropyl methyl cellulose, etc. The dispersant is at least one of polyacrylic acid, acetone, etc.

[0026] In the catalyst preparation method of the present invention, the modified TS-1 molecular sieve, binder, dispersant, and water in step (2) are mixed in a mass ratio of 15-30:1-3:1:100. The composite slurry can be prepared by methods such as beating and ball milling.

[0027] In the catalyst preparation method of the present invention, the mesh number of the honeycomb carrier in step (2) is 200-400 mesh, and a cordierite honeycomb ceramic carrier is preferably used. The immersion time of the honeycomb carrier in the slurry is 1-2 min. After taking it out, blow off the residual liquid, dry at 100-120 °C for 4-6 h, and calcine at 500-550 °C for 1-3 h to obtain a carrier coated with a modified TS-1 molecular sieve coating.

[0028] In the catalyst preparation method of the present invention, in step (3), the active metal is Pt, and preferably further includes one or more of Pd, Au, and Ir. The concentration of Pt is 2.5 - 5 g / L, and the content of one or more of Pd, Au, and Ir is prepared according to 0.1 - 0.5 times the content of Pt.

[0029] In the catalyst preparation method of the present invention, the active metal solution in step (3) is its soluble salt, preferably a chlorine-containing compound or nitrate, such as chloroplatinic acid, platinum nitrate, palladium chloride, palladium nitrate, chloroauric acid, chloroiridic acid, etc., which is specifically determined according to the selected active metal.

[0030] In the catalyst preparation method of the present invention, the time for the coated carrier to be immersed in the active metal solution in step (3) is 2 - 5 min. After taking it out, the residual liquid is blown off, dried at 100 - 120 °C for 4 - 6 h, and calcined at 450 - 500 °C for 1 - 2 h.

[0031] In the present invention, the straw explosion waste gas comes from the upper gas-phase discharge of the straw explosion discharge cyclone separator, mainly including water vapor, acid mist, organic pollutants, etc. The organic pollutants are mainly furfural, furan, etc. After being treated by the method of the present invention, the total hydrocarbon concentration of the discharged purified gas ≤ 50 mg / m 3 。

[0032] In the present invention, the catalytic oxidation reaction conditions are: the reaction space velocity is 1000 - 30000 h -1 , and the reaction temperature is 200 - 550 °C.

[0033] The second aspect of the present invention provides a treatment device for the above-mentioned straw explosion waste gas treatment method, mainly including a washing unit, a desorption unit, and a catalytic oxidation unit. The washing unit mainly includes a washing tower, which is used to capture steam, acid mist, and some organic pollutants such as furfural from the cyclone separator. The washed gas flow is sent to the catalytic oxidation unit; the desorption unit mainly includes a desorption tower, which is used to strip the organic pollutants, and the generated gas flow is sent to the catalytic oxidation unit for treatment; the catalytic oxidation unit mainly includes a conveying system, a heating system, and a catalytic oxidation reactor, which is used to remove the organic pollutants in the waste gas. The reactor is filled with a water-resistant catalytic oxidation catalyst.

[0034] In the device of the present invention, the conveying system mainly includes a circulation fan for gas transportation; the heating system mainly includes a heat exchanger and a heater, which are used to heat the gas flow to the temperature required for catalytic oxidation reaction.

[0035] In the device of the present invention, a pump is set to send the bottom liquid of the washing tower to the upper part of the desorption tower, and the bottom liquid of the desorption tower is sent to the upper part of the washing tower after cooling.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) In view of the characteristics of the straw explosion waste gas, the present invention adopts a combined process of washing absorption - stripping desorption and catalytic oxidation, which can not only efficiently remove organic pollutants in the waste gas, but also maintain the long - term stable operation of the device, avoiding the adverse effects of acid mist and steam.

[0038] (2) A detergent is used to capture steam, acid mist and some organic pollutants in the waste gas. At the same time, stripping desorption is combined, which avoids the entry of a large amount of water vapor, acid mist and other substances unfavorable to the catalyst into the catalytic oxidation unit, and at the same time promotes the maximum entry of organic pollutants into the desorption gas stream, finally realizing the efficient treatment of the waste gas and ensuring the service life of the catalyst.

[0039] (3) Tetrachlorosilane and acetone are used to modify TS - 1 molecular sieve synergistically. The modified TS - 1 molecular sieve is used as the main coating component, and at the same time, Pt is selected as the main active component, which can inhibit the loss of active sites caused by the migration and aggregation of Pt under high water vapor. While realizing the efficient loading of the active metal, the water resistance of the catalyst is improved, and the catalyst can still maintain high catalytic activity and stability after long - term operation.

[0040] (4) The washing liquid generated by the washing in the present invention can be recycled as the dilute acid preparation water for straw dilute acid explosion, reducing the generation of waste water; at the same time, since pollutants such as furfural are efficiently removed, the recycling of the washing liquid will not affect the subsequent enzymatic hydrolysis and fermentation processes. Brief Description of the Drawings

[0041] Figure 1 is a process flow chart of the treatment method of the present invention. Detailed Embodiments

[0042] The technical solutions and their implementation effects of the present invention will be further described below through examples. The examples are implemented on the premise of the technical solutions of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0043] The experimental methods in the following examples are all conventional methods in the art unless otherwise specified. The experimental materials used in the following examples are all purchased from regular biochemical reagent stores unless otherwise specified.

[0044] The treatment device for straw explosion waste gas adopted in the embodiments of the present invention is as shown in the appendix Figure 1As shown in the figure, it mainly includes an induced draft fan, a scrubbing tower, a scrubbing tower pump, a desorption tower, a cooler, a desorption tower pump, and a catalytic oxidation unit. The catalytic oxidation unit mainly includes a recycle fan, a heat exchanger, a heater, and a catalytic oxidation reactor. Under the action of the induced draft fan, the exploded waste gas enters the scrubbing tower from bottom to top, contacts the detergent countercurrently, and captures some organic pollutants such as steam, acid mist, and furfural in the exploded waste gas from the cyclone separator. The washed gas flow is sent to the catalytic oxidation unit. The bottom liquid of the scrubbing tower enters the upper part of the desorption tower under the action of the scrubbing tower pump for air stripping. Air is used for air stripping, and preferably a part of the purified gas from the catalytic oxidation unit is used. The generated gas flow is drawn out from the top of the desorption tower and sent to the catalytic oxidation unit for treatment. Under the action of the catalytic oxidation catalyst, the organic pollutants are oxidized into CO2 and H2O. After recovering heat through the heat exchanger, a part of the purified gas returns to the desorption tower as the air stripping gas, and the remaining part is directly discharged. The bottom liquid of the desorption tower enters the cooler under the action of the desorption tower pump, and after cooling, enters the scrubbing tower as the detergent.

[0045] Example 1

[0046] Using the process described in the present invention Figure 1 to treat the exploded waste gas of straw. At the front end, dilute sulfuric acid explosion pretreatment of corn straw is adopted. The generated exploded waste gas comes out from the cyclone separator, and the steam volume is about 160 m 3 / h. Among them, the total hydrocarbon is 500 - 2500 mg / m 3 , and the water vapor content is 30% - 90%.

[0047] Water is used as the detergent, and the dosage of water is such that the liquid-gas ratio is 9 - 20 L / m 3 . The scrubbing tower adopts a packed tower, and the packing adopts polypropylene cascade rings for countercurrent contact. The temperature of the detergent is 60 °C. The bottom liquid after washing enters from the upper part of the desorption tower. The desorption tower adopts a packed tower, and the packing adopts polypropylene cascade rings. The liquid-gas ratio is 1 - 3 L / m 3 , the temperature of the gas entering the desorption tower is 75 - 80 °C. After stripping out the organic pollutants, it enters the catalytic oxidation unit for treatment. The bottom liquid of the desorption tower enters the cooler and is used as the detergent after cooling. An anti-water catalytic oxidation catalyst is filled in the catalytic oxidation reactor, and the space velocity is 10000 h -1 . In the waste gas entering the catalytic oxidation reactor, the water content is 30% - 35%, and the inlet temperature of the catalytic oxidation reactor is regulated to 300 °C. After 1000 h of treatment, the total hydrocarbon concentration is stably less than 20 mg / m 3 .

[0048] The preparation method of the water-resistant catalytic oxidation catalyst is as follows: (1) Mix TS-1 molecular sieve, tetrachlorosilane, and acetone in a mass ratio of 1:20:20, reflux and react at 75 °C for 6 h. After filtration, wash with ethanol until no chloride ions are detected, and dry at 100 °C for 5 h to obtain modified TS-1 molecular sieve. The specific surface area of the TS-1 molecular sieve is about 400 m 2 / g, and the pore volume is 0.4 cm 3 / g, obtained by purchase. (2) Mix the modified TS-1 molecular sieve material, methylcellulose, acetone, and water in a ratio of 30:1:1:100 to form a slurry. Immerse a 200-mesh cordierite honeycomb ceramic carrier in the slurry, impregnate for 2 min, blow off the residual liquid, dry at 110 °C for 5 h, and calcine at 525 °C for 2 h to obtain a carrier coated with a modified TS-1 molecular sieve coating. (3) Immerse the coated carrier in a mixed solution of chloroplatinic acid and palladium chloride, where the concentration of Pt is 4.5 g / L and the ratio of Pt to Pd is 1:0.25. Immerse for 3 min, blow off the residual liquid, dry at 100 °C for 6 h, and calcine at 475 °C for 1.5 h to obtain a monolithic catalyst. Calculated by the total mass of the catalyst, the content of the modified TS-1 molecular sieve coating is 7.52%, and the content of the active metal component is 0.181%.

[0049] Example 2

[0050] Same as Example 1, except that: The preparation method of the water-resistant catalytic oxidation catalyst is as follows: (1) Mix TS-1 molecular sieve, tetrachlorosilane, and acetone in a mass ratio of 1:25:15, reflux and react at 80 °C for 6 h. After filtration, wash with ethanol until no chloride ions are detected, and dry at 100 °C for 5 h to obtain modified TS-1 molecular sieve. (2) Mix the modified TS-1 molecular sieve material, methylcellulose, acetone, and water in a ratio of 20:2:1:100 to form a slurry. Immerse a 200-mesh cordierite honeycomb ceramic carrier in the slurry, impregnate for 2 min, blow off the residual liquid, dry at 120 °C for 3 h, and calcine at 550 °C for 2 h to obtain a carrier coated with a modified TS-1 molecular sieve coating. (3) Immerse the coated carrier in a mixed solution of chloroplatinic acid and palladium chloride, where the concentration of Pt is 2.5 g / L and the ratio of Pt to Pd is 1:0.5. Immerse for 3 min, blow off the residual liquid, dry at 100 °C for 6 h, and calcine at 500 °C for 2 h to obtain a monolithic catalyst. Calculated by the total mass of the catalyst, the content of the modified TS-1 molecular sieve coating is 6.85%, and the content of the active metal component is 0.157%. After 1000 h of treatment, the total hydrocarbon concentration is stably less than 41 mg / m 3 .

[0051] Example 3

[0052] Same as Example 1, except that: The preparation method of the water-resistant catalytic oxidation catalyst is as follows: (1) Mix TS-1 molecular sieve, tetrachlorosilane, and acetone in a mass ratio of 1:30:10, reflux and react at 70 °C for 10 h. After filtration, wash with ethanol until no chloride ions are detected, and dry at 120 °C for 2 h to obtain modified TS-1 molecular sieve. (2) Mix the modified TS-1 molecular sieve material with methylcellulose, acetone, and water in a ratio of 15:3:1:100 to form a slurry. Immerse a 200-mesh cordierite honeycomb ceramic carrier in the slurry for 2 min, blow off the residual liquid, dry at 100 °C for 5 h, and calcine at 500 °C for 3 h to obtain a carrier coated with a modified TS-1 molecular sieve coating. (3) Immerse the coated carrier in a mixed solution of chloroplatinic acid and palladium chloride, where the concentration of Pt is 3.5 g / L and the ratio of Pt to Pd is 1:0.15. Immerse for 3 min, blow off the residual liquid, dry at 100 °C for 4 h, and calcine at 450 °C for 2 h to obtain the monolithic catalyst. By mass of the whole catalyst, the content of the modified TS-1 molecular sieve coating is 6.14%, and the content of the active metal component is 0.151%. After 1000 h of treatment, the total hydrocarbon concentration is stably less than 34.5 mg / m 3 .

[0053] Example 4

[0054] Same as Example 1, except that: The gas used for stripping is air. After 1000 h of treatment, the total hydrocarbon concentration is stably less than 20 mg / m 3 .

[0055] Comparative Example 1

[0056] Same as Example 1, except that: In the catalytic oxidation catalyst, TS-1 molecular sieve is used instead of modified TS molecular sieve. Due to the limited water resistance of the catalyst, the service life of the catalyst is shortened. After 512 h of treatment, the total hydrocarbon concentration is higher than 120 mg / m 3 , not meeting the national environmental protection standards.

[0057] Comparative Example 2

[0058] Same as Example 1, except that: In the catalytic oxidation catalyst, ZSM-5 molecular sieve is used instead of modified TS molecular sieve. Due to the limited water resistance of the catalyst, the service life of the catalyst is shortened. After 480 h of treatment, the total hydrocarbon concentration is higher than 120 mg / m 3 , not meeting the national environmental protection standards.

[0059] Comparative Example 3

[0060] Same as Example 1, except that: the desorption tower is not provided, and the gas stream after washing directly enters the catalytic oxidation unit for treatment. Since a large amount of aldehyde organic substances such as furfural accumulate in the bottom liquid of the washing tower, the difficulty of wastewater treatment is increased. Moreover, considering the adverse effects of organic pollutants on subsequent enzymatic hydrolysis and fermentation, it is not suitable to be recycled to the straw explosion process.

[0061] Comparative Example 4

[0062] Same as Example 1, except that: the explosion exhaust gas directly enters the catalytic oxidation treatment. Due to the influence of acid mist, steam, etc. in the exhaust gas, the service life of the catalyst is severely shortened. After 24 hours of treatment, the total hydrocarbon concentration of the purified gas is 3 120 mg / m , not meeting the national environmental protection standards.

Claims

1. A method for treating waste gas from straw steam explosion, characterized in that The steps include: (1) The steam explosion waste gas is transported to the scrubber, and the steam, acid mist and some organic pollutants in the waste gas are captured by the scrubber. After scrubbing, the gas flow enters the catalytic oxidation unit; (2) The bottom liquid of the scrubber tower enters the desorption tower for gas stripping, and the generated gas flow is sent to the catalytic oxidation unit for treatment; (3) The catalytic oxidation unit mainly includes a catalytic oxidation reactor loaded with a water-resistant catalytic oxidation catalyst.

2. The method according to claim 1, characterized in that: Step (1) The washing tower uses water as a washing agent, and the amount of water used is such that the liquid-gas ratio is 3-50 L / m 3 The washing tower adopts a packed tower or a spray tower, and the packing adopts any one or a mixture of ceramic or plastic ball rings, step rings, and rectangular saddle packings.

3. The method according to claim 1 or 2, characterized in that: Step (1) The waste gas from the steam explosion of straw enters the washing tower from bottom to top, and contacts with the detergent in countercurrent, and the temperature of the detergent is adjusted to 40-90°C, preferably 50-80°C.

4. The method according to claim 1, characterized in that: Step (2) The desorption tower adopts a packed tower or a spray tower, and the liquid-gas ratio is 1-10L / m 3 The filler used is any one or a mixture of ceramic, plastic ball rings, step rings, and rectangular saddle fillers.

5. The method according to claim 1, characterized in that: In step (2), air is used for gas stripping, preferably part of the purified gas discharged from the catalytic oxidation unit is used for gas stripping, and the temperature of the gas entering the desorption tower is regulated to be 50-95°C, preferably 60-85°C.

6. The method according to claim 1, characterized in that: The washed liquid phase in step (2) enters the desorption tower from the top, and after gas stripping in the desorption tower, the generated gas flow enters the catalytic oxidation unit, and the bottom liquid enters the cooler and is used as a washing agent after cooling.

7. The method according to claim 1, characterized in that: The water-resistant catalytic oxidation catalyst in step (3) is an integral catalyst with a honeycomb carrier as a matrix, a modified TS-1 molecular sieve as a carrier coating, and a precious metal as an active metal. Based on the integral catalyst, the modified TS-1 molecular sieve coating content is 3%-8%, and the active metal content is 0.05%-0.2%.

8. The method according to claim 7, characterized in that: In the catalytic oxidation catalyst, the mesh number of the honeycomb carrier is 200-400 mesh, preferably a cordierite honeycomb ceramic carrier; the active metal is Pt, preferably also including one or more of Pd, Au, Ir, and the content of one or more of Pd, Au, Ir is 0.1-0.5 times the content of Pt.

9. The method according to claim 7, characterized in that: The modification method of the modified TS-1 molecular sieve is as follows: TS-1 molecular sieve, tetrachlorosilane and acetone are mixed, refluxed at 70-80° C., and the modified TS-1 molecular sieve is obtained by filtering, washing and drying.

10. The method according to claim 1, 7, 8 or 9, characterized in that The preparation method of the water-resistant catalytic oxidation catalyst is: (1) TS-1 molecular sieve, tetrachlorosilane and acetone are mixed, refluxed at 70-80°C, filtered, washed and dried to obtain modified TS-1 molecular sieve; (2) The modified TS-1 molecular sieve is mixed with a binder, a dispersant and water in proportion to prepare a slurry, and the honeycomb carrier is immersed in the slurry of step (1), and a coated carrier is obtained after purging, drying and calcining; (3) The coated carrier is immersed in an active metal solution, and then purged, dried, and calcined to obtain a monolithic catalyst.

11. The method according to claim 10, characterized in that: Step (1) The specific surface area of ​​TS-1 molecular sieve is 400-450m 2 / g, pore volume is 0.39-0.41cm 3 / g.

12. The method according to claim 10 or 11, characterized in that: Step (1) TS-1 molecular sieve, tetrachlorosilane and acetone are mixed in a mass ratio of 1:20-30:10-20; after mixing, reflux reaction is carried out at 70-80° C. for 6-10 hours; after the reaction is completed, filtering, washing with ethanol until no chloride ions are detected, and drying at 100-120° C. for 2-5 hours to obtain a modified TS-1 molecular sieve.

13. The method according to claim 10, characterized in that: In step (2), the binder is at least one of methyl cellulose and hydroxypropyl methyl cellulose; and the dispersant is at least one of polyacrylic acid and acetone.

14. The method according to claim 10 or 13, characterized in that: Step (2) The modified TS-1 molecular sieve, binder, dispersant and water are mixed in a mass ratio of 15-30:1-3:1:100; a composite slurry is obtained by pulping or ball milling.

15. The method according to claim 10, characterized in that: The mesh number of the honeycomb carrier in step (2) is 200-400 mesh, and a cordierite honeycomb ceramic carrier is preferred.

16. The method according to claim 10 or 15, characterized in that: The honeycomb carrier described in step (2) is immersed in the slurry for 1-2 minutes; after being taken out, the residual liquid is blown off, dried at 100-120°C for 4-6 hours, and calcined at 500-550°C for 1-3 hours to obtain a carrier coated with a modified TS-1 molecular sieve coating.

17. The method according to claim 10, characterized in that: In step (3), the active metal is Pt, and preferably also includes one or more of Pd, Au, and Ir, wherein the concentration of Pt is 2.5-5 g / L, and the content of one or more of Pd, Au, and Ir is prepared to be 0.1-0.5 times the content of Pt.

18. The method according to claim 10, characterized in that: In step (3), the coated carrier is immersed in the active metal solution for 2-5 minutes; after being taken out, the residual liquid is blown off, and the carrier is dried at 100-120°C for 4-6 hours and calcined at 450-500°C for 1-2 hours.

19. The method according to claim 1, characterized in that: The waste gas from straw steaming and explosion comes from the upper gas phase discharge of the straw steaming and explosion discharge cyclone separator, and mainly includes water vapor, acid mist, and organic pollutants, wherein the organic pollutants are mainly furfural and furan.

20. The method according to claim 1, characterized in that: The catalytic oxidation reaction conditions are: reaction space velocity 1000-30000h -1 , reaction temperature 200-550℃.

21. A treatment device for the straw steam explosion waste gas treatment method according to any one of claims 1 to 20, characterized in that It mainly includes a washing unit, a desorption unit and a catalytic oxidation unit. The washing unit mainly includes a washing tower, which is used to capture steam, acid mist and some organic pollutants from the cyclone separator. The airflow after washing is sent to the catalytic oxidation unit for treatment; the desorption unit mainly includes a desorption tower, which is used to extract organic pollutants from the gas, and the generated airflow is sent to the catalytic oxidation unit for treatment; the catalytic oxidation unit mainly includes a conveying system, a heating system and a catalytic oxidation reactor, which are used to remove organic pollutants from the exhaust gas. The catalytic oxidation reactor is filled with a water-resistant catalytic oxidation catalyst.

22. The device according to claim 21, characterized in that: The conveying system mainly includes a circulating fan for conveying gas; the heating system mainly includes a heat exchanger and a heater for heating the gas flow to the temperature required for the catalytic oxidation reaction.

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