Method for recycling byproduct of refined pyrethrin product

Abstract

The invention belongs to the technical field of insecticide byproducts, and provides a byproduct recycling method of a refined pyrethrin product. The recycling method comprises the following steps: (1) collecting by-products; (2) detoxification treatment: performing high-temperature steam treatment on the disintegrating slag, and cooling to obtain pretreated disintegrating slag; mixing the pretreated disintegrating slag with an ethanol water solution, and performing ultrasonic extraction; after the extraction is finished, carrying out solid-liquid centrifugal separation to obtain primarily detoxified residues; mixing the preliminarily detoxified residues with a solution of a compound enzyme, performing enzymolysis, and then filtering to obtain deeply detoxified residues; (3) drying treatment: drying the deeply detoxified residues to obtain pretreated residues; and (4) preparing biomass particles: adding auxiliary materials into the pretreated residues, granulating, cooling and screening to obtain the biomass particles. According to the recycling method, biomass components in the solid residues generated after fine extraction of pyrethrin can be converted into biomass energy, the problem of byproduct treatment can be solved, environmental pollution can be reduced, resource recycling can be achieved, and economic value can be created.

Description

Technical Field

[0001] The invention belongs to the technical field of insecticide by-product treatment, and in particular relates to a method for recycling by-products of refined pyrethroid products. Background Art

[0002] Pyrethrin, a pale yellow oily liquid extracted from the dried flowers of pyrethrum, is recognized worldwide as an ideal natural insecticide. It not only has excellent contact effectiveness against a wide range of pests, but is also minimally toxic to humans and warm-blooded animals. It decomposes rapidly in the natural environment, leaving no residue and seldom causing resistance. Due to its rapid effectiveness, low toxicity, low resistance, broad spectrum, and repellent properties, pyrethrin is widely used in environmental sanitation, agriculture, and forestry for pest control and repellency.

[0003] Pyrethrin production in China and abroad primarily relies on methods such as organic solvent extraction, supercritical CO2 extraction, and subcritical fluid extraction. These methods produce pyrethrins as oleoresins containing large amounts of wax, pigment, resinous colloid, and free fatty acids, which severely impact their quality and restrict their application. Pyrethrins must be refined before they can be used as products.

[0004] The production of refined pyrethroids produces a certain amount of byproducts. Discharging these byproducts without proper utilization would, on the one hand, result in a significant waste of resources, as they may contain potentially valuable chemical components; on the other hand, their indiscriminate discharge would cause severe environmental pollution and increase environmental remediation costs.

[0005] Currently, there are limited technologies for treating the by-products of refined pyrethroid products. Traditional treatment methods are mostly simple incineration or landfilling. The incineration process may not only produce harmful gases, such as gases containing toxic and harmful components such as chlorine, which will pollute the atmospheric environment, but also waste the potential resources that may be contained in the by-products. Landfill treatment may cause harmful substances in the by-products to seep into the soil and groundwater. Long-term accumulation will cause damage to the soil and water ecology, and occupy a large amount of precious land resources. Some companies have attempted to conduct preliminary separation of the by-products, but due to technical limitations, the separation effect is poor and it is impossible to effectively extract components with economic value. The processing cost is high and the efficiency is low, making it difficult to achieve large-scale industrial application.

[0006] Therefore, developing an efficient, environmentally friendly and economically feasible method for treating pyrethroid refined product by-products has both social and economic significance. Summary of the Invention

[0007] To address the aforementioned shortcomings of the prior art, the present invention provides a method for recycling byproducts of refined pyrethroid products. This method converts the biomass components in the solid residues produced after pyrethroid extraction into biomass energy, thereby resolving byproduct disposal issues and reducing environmental pollution while also enabling resource recycling and creating economic value.

[0008] In order to achieve the above object, the solution adopted by the present invention is:

[0009] A method for recycling by-products of pyrethrin refined products, comprising: (1) by-product collection: collecting solid residues after pyrethrin refined products, removing foreign matter, and crushing the solid residues to obtain slag; (2) detoxification treatment: placing the slags in a high-temperature steam treatment machine, at a temperature of 120-150° C. and a steam pressure of 0.15-0.3 MPa, high-temperature steam treatment for 30-40 minutes, and then cooling to obtain pre-treated slag; mixing the pre-treated slags with 60-70% by volume of ethanol water; The solutions are mixed and then ultrasonically extracted; after the extraction, the solid and liquid are centrifuged to obtain a preliminary detoxification residue; the preliminary detoxification residue is mixed with a solution of a composite enzyme and then enzymatically hydrolyzed, followed by filtration to obtain a deep detoxification residue; the composite enzyme includes cellulase, ligninase and pyrethroid degrading enzyme in a mass ratio of 1:1:1; (3) drying treatment: the deep detoxification residue is dried to obtain a pre-treated residue; (4) biomass particle preparation: the pre-treated residue is added with auxiliary materials and then extruded into granules, and then cooled and sieved to obtain biomass particles.

[0010] Furthermore, in a preferred embodiment of the present invention, in step (2), the conditions for ultrasonic extraction include: a solid-liquid ratio of the pretreated slag to the ethanol aqueous solution of 1:4-6, an ultrasonic frequency of 20-40 kHz, and an ultrasonic power density of 0.2-0.5 W / cm 2 , the extraction temperature is 30-40℃, and the extraction time is 20-30min.

[0011] Furthermore, in a preferred embodiment of the present invention, in step (2), the conditions for centrifugal separation include: a rotation speed of 3000-4000 r / min and a time of 10-15 min.

[0012] Furthermore, in a preferred embodiment of the present invention, in step (2), the enzymatic hydrolysis conditions include: the addition amount of the complex enzyme is 0.5-1.0% of the mass of the initial detoxification residue, the enzymatic hydrolysis temperature is 40-50°C, the pH value is 5.5-6.5, and the enzymatic hydrolysis time is 4-6h.

[0013] Furthermore, in a preferred embodiment of the present invention, in step (3), the deep detoxification residue is first subjected to low-temperature vacuum drying and then to hot air drying.

[0014] Furthermore, in a preferred embodiment of the present invention, the conditions for low-temperature vacuum drying include: a vacuum degree of -0.08 to -0.10 MPa, a drying temperature of 40-50° C., and a drying time of 1-2 hours.

[0015] Furthermore, in a preferred embodiment of the present invention, the conditions for hot air drying include: a temperature of 80-100° C. and a drying time of 30-60 minutes.

[0016] Furthermore, in a preferred embodiment of the present invention, in step (4), the preparation of biomass particles includes: adding 2-5% starch to the pretreatment residue, mixing and spraying water to obtain a mixture, wherein the water content of the mixture is 12-15%; feeding the mixture into a ring die pelletizer at a speed of 80-120 r / min and a roller pressure of 5-8 MPa for extrusion granulation; then cooling through a countercurrent cooler, the cooling medium is room temperature air, cooling for 10-15 minutes, and the cooled particles are screened through a vibrating screen to obtain biomass particles.

[0017] The beneficial effects of the method for recycling by-products of refined pyrethroids provided by the present invention are:

[0018] (1) The solid residue after pyrethroid extraction mainly contains cellulose, hemicellulose, lignin, a small amount of residual pyrethroids, and other organic impurities. Among them, cellulose and hemicellulose are the main components converted into biomass energy; residual pyrethroids must be completely removed during the treatment process to avoid affecting subsequent energy production and application.

[0019] The method for recycling by-products of refined pyrethrin products provided by the present invention can completely remove residual pyrethrins and convert by-products such as cellulose, hemicellulose, and lignin into biomass energy. This can not only solve the problem of by-product disposal and reduce environmental pollution, but also realize resource recycling and create economic value, thereby achieving the reduction, harmlessness and resource utilization of pyrethrin by-products, while taking into account both environmental and economic benefits.

[0020] (2) The method for recycling the by-products of the pyrethroid refined product provided by the present invention comprises, in the detoxification step, first performing a mild high-temperature steam treatment, then using a specific organic solvent chemical ultrasonic extraction, and then performing an enzymatic hydrolysis treatment.

[0021] The above treatment method uses the thermal effect of steam to destroy part of the toxin structure by heat, while softening the material tissue, increasing the permeability and opening the pores, which is conducive to the subsequent chemical reagents to penetrate into the interior of the material faster and more fully, combine with the toxins and extract them out; the cavitation effect and mechanical effect generated by ultrasound can accelerate the dissolution of residual toxic and harmful substances such as pyrethroids from the residue, improve the extraction efficiency, and ensure that the removal rate of residual pyrethroids reaches more than 99%; biological enzymes can specifically decompose residual pyrethroids and other organic impurities, further reducing the content of toxic substances in the residue.

[0022] The various steps work together to completely remove the residual pyrethrins and other toxic and harmful substances in the residue.

[0023] (3) The method for recycling the byproducts of the pyrethroid refined product provided by the present invention adopts a multi-stage drying system: low-temperature vacuum drying is first used, followed by hot air drying. Low-temperature vacuum drying can quickly remove moisture at a lower temperature, avoiding high temperature damage to the active ingredients in the residue, while reducing energy consumption. Hot air drying further reduces the moisture content of the residue to meet the requirements of subsequent extrusion granulation. The two work together to reduce energy consumption, retain the active ingredients, improve drying efficiency, and also reduce energy consumption. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0025] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0026] Example 1

[0027] (1) By-product collection: Collect the solid residue after pyrethroid extraction, remove foreign matter such as stones and metals, and crush the solid residue to obtain debris with a particle size of less than 5 mm;

[0028] (2) Detoxification treatment: The slag was placed in a high-temperature steam treatment machine at a temperature of 135°C and a steam pressure of 0.18 MPa for 35 min and then cooled to obtain pretreated slag; the pretreated slag was mixed with a 65% volume fraction of ethanol aqueous solution at a solid-liquid ratio of 1:5 and ultrasonically heated at a frequency of 30 kHz and an ultrasonic power density of 0.4 W / cm 2, the extraction temperature is 35°C, and the extraction time is 25 minutes; after the extraction, the rotation speed is 3500r / min, and the solid-liquid centrifugation is carried out for 13 minutes to obtain a preliminary detoxification residue; the preliminary detoxification residue is mixed with a solution of a composite enzyme and then enzymatically hydrolyzed at a temperature of 45°C and a pH value of 6.0 for 5 hours, followed by filtration to obtain a deeply detoxified residue; the composite enzyme includes cellulase, ligninase and pyrethroid degrading enzyme in a mass ratio of 1:1:1; the amount of the composite enzyme added is 0.8% of the mass of the preliminary detoxification residue;

[0029] (3) Drying: The deep detoxification residue was dried at 90°C with hot air for 60 min to obtain a pre-treated residue;

[0030] (4) Preparation of biomass pellets: 3% starch was added to the pretreatment residue, and the mixture was sprayed with water to obtain a mixture with a water content of 14%. The mixture was fed into a ring die pelletizer and extruded and granulated at a speed of 100 r / min and a roller pressure of 7 MPa. The mixture was then cooled in a countercurrent cooler with room temperature air as the cooling medium for 13 minutes. The cooled pellets were screened through a vibrating screen to obtain biomass pellets.

[0031] Example 2

[0032] This embodiment provides a method for recycling by-products of refined pyrethroids, which differs from Example 1 in that:

[0033] (2) Detoxification treatment: The slag was placed in a high-temperature steam treatment machine at a temperature of 120°C and a steam pressure of 0.3 MPa for 30 min and then cooled to obtain pretreated slag; the pretreated slag was mixed with a 70% ethanol aqueous solution with a solid-liquid ratio of 1:4 and ultrasonically heated at a frequency of 40 kHz and an ultrasonic power density of 0.2 W / cm 2 The extraction temperature is 40°C and the extraction time is 20 minutes. After the extraction, the solid-liquid centrifugation is carried out at a rotation speed of 4000 r / min for 10 minutes to obtain a preliminary detoxification residue. The preliminary detoxification residue is mixed with a solution of a composite enzyme and then enzymatically hydrolyzed at a temperature of 50°C and a pH value of 5.5 for 6 hours, followed by filtration to obtain a deeply detoxified residue. The composite enzyme includes cellulase, ligninase and pyrethroid degrading enzyme in a mass ratio of 1:1:1. The amount of the composite enzyme added is 0.5% of the mass of the preliminary detoxification residue.

[0034] (4) Preparation of biomass pellets: 2-5% starch was added to the pretreatment residue, and the mixture was sprayed with water to obtain a mixture with a water content of 12%. The mixture was fed into a ring die pellet machine and extruded into pellets at a speed of 120 r / min and a roller pressure of 5 MPa. The mixture was then cooled in a countercurrent cooler with room temperature air as the cooling medium for 15 minutes. The cooled pellets were screened through a vibrating screen to obtain biomass pellets.

[0035] Example 3

[0036] This embodiment provides a method for recycling by-products of refined pyrethroids, which differs from Example 1 in that:

[0037] (2) Detoxification treatment: The slag was placed in a high-temperature steam treatment machine at a temperature of 150°C and a steam pressure of 0.15 MPa for 40 min and then cooled to obtain pretreated slag; the pretreated slag was mixed with a 60% ethanol aqueous solution with a solid-liquid ratio of 1:6 and ultrasonically heated at a frequency of 20 kHz and an ultrasonic power density of 0.5 W / cm 2 The extraction temperature is 30°C and the extraction time is 30 minutes. After the extraction, the solid-liquid centrifugation is carried out at a rotation speed of 3000 r / min for 15 minutes to obtain a preliminary detoxification residue. The preliminary detoxification residue is mixed with a solution of a composite enzyme and then enzymatically hydrolyzed at a temperature of 40°C and a pH value of 6.5 for 4 hours, followed by filtration to obtain a deeply detoxified residue. The composite enzyme includes cellulase, ligninase and pyrethroid degrading enzyme in a mass ratio of 1:1:1. The amount of the composite enzyme added is 1.0% of the mass of the preliminary detoxification residue.

[0038] (4) Preparation of biomass pellets: 5% starch was added to the pretreatment residue, and the mixture was sprayed with water to obtain a mixture with a water content of 12%. The mixture was fed into a ring die pellet machine and extruded into pellets at a speed of 120 r / min and a roller pressure of 5 MPa. The mixture was then cooled in a countercurrent cooler with room temperature air as the cooling medium for 15 minutes. The cooled pellets were screened through a vibrating screen to obtain biomass pellets.

[0039] Example 4

[0040] This embodiment provides a method for recycling by-products of refined pyrethroids, which differs from Example 1 in that: (3) Drying treatment: The deep detoxification residue is first subjected to low-temperature vacuum drying at a vacuum degree of -0.09 MPa and a drying temperature of 45°C for 1.5 hours, and then subjected to hot air drying at a temperature of 90°C for 40 minutes to obtain a pretreated residue.

[0041] Example 5

[0042] This embodiment provides a method for recycling by-products of refined pyrethroid products, which differs from Example 1 in that: (3) Drying treatment: the deep detoxification residue is first subjected to low-temperature vacuum drying at a vacuum degree of -0.08 MPa and a drying temperature of 50°C for 1 hour, and then subjected to hot air drying at a temperature of 80°C for 60 minutes to obtain a pretreated residue.

[0043] Example 6

[0044] This embodiment provides a method for recycling by-products of refined pyrethroids, which differs from Example 1 in that: (3) Drying treatment: The deep detoxification residue is first subjected to low-temperature vacuum drying at a vacuum degree of -0.1 MPa and a drying temperature of 50°C for 2 hours, and then subjected to hot air drying at a temperature of 100°C for 30 minutes to obtain a pretreated residue.

[0045] Comparative Example 1

[0046] This comparative example provides a method for recycling by-products of refined pyrethroids, comprising:

[0047] (1) By-product collection: Collect the solid residue after pyrethroid extraction, remove foreign matter such as stones and metals, and crush the solid residue to obtain debris with a particle size of less than 5 mm;

[0048] (2) Detoxification treatment: The crushed residue was mixed with 65% ethanol aqueous solution at a solid-liquid ratio of 1:5, and ultrasonic frequency was 30 kHz and ultrasonic power density was 0.4 W / cm 2 The extraction temperature was 35°C and the extraction time was 25 min. After the extraction, the rotation speed was 3500 r / min and the solid-liquid centrifugation was performed for 13 min to obtain the detoxified residue.

[0049] (3) Drying: The detoxified residue was dried at 90°C with hot air for 60 min to obtain a pretreated residue;

[0050] (4) Preparation of biomass pellets: 3% starch was added to the pretreatment residue, and the mixture was sprayed with water to obtain a mixture with a water content of 14%. The mixture was fed into a ring die pelletizer and extruded and granulated at a speed of 100 r / min and a roller pressure of 7 MPa. The mixture was then cooled in a countercurrent cooler with room temperature air as the cooling medium for 13 minutes. The cooled pellets were screened through a vibrating screen to obtain biomass pellets.

[0051] Comparative Example 2

[0052] This comparative example provides a method for recycling by-products of pyrethroid refined products, which differs from Example 1 in that: (2) detoxification treatment: placing the slag in a high-temperature steam treatment machine at a temperature of 135°C and a steam pressure of 0.18 MPa, high-temperature steam treatment for 35 minutes, and then cooling to obtain pretreated slag; mixing the pretreated slag with a 65% volume fraction of ethanol aqueous solution at a solid-liquid ratio of 1:5, and ultrasonically treating the slag at an ultrasonic frequency of 30 kHz and an ultrasonic power density of 0.4 W / cm 2 The extraction temperature was 35°C and the extraction time was 25 min. After the extraction, the rotation speed was 3500 r / min and the solid-liquid centrifugation was performed for 13 min to obtain the detoxified residue.

[0053] Comparative Example 3

[0054] This comparative example provides a method for recycling by-products of pyrethroid refined products, which differs from Example 1 in that: (2) detoxification treatment: the crushed residue is mixed with a 65% ethanol aqueous solution with a solid-liquid ratio of 1:5, and then ultrasonically heated at a frequency of 30 kHz and an ultrasonic power density of 0.4 W / cm 2 The extraction temperature is 35°C and the extraction time is 25 minutes. After the extraction, the rotation speed is 3500r / min and the solid-liquid centrifugation is carried out for 13 minutes to obtain a preliminary detoxification residue. The preliminary detoxification residue is mixed with a solution of a composite enzyme and then enzymatically hydrolyzed for 5 hours at a hydrolysis temperature of 45°C and a pH value of 6.0, followed by filtration to obtain a deeply detoxified residue. The composite enzyme includes cellulase, ligninase and pyrethroid degrading enzyme in a mass ratio of 1:1:1. The amount of the composite enzyme added is 0.8% of the mass of the preliminary detoxification residue.

[0055] Comparative Example 4

[0056] This comparative example provides a method for recycling by-products of pyrethroid refined products, which differs from Example 1 in that: (2) detoxification treatment: placing the slag in a high-temperature steam treatment machine at a temperature of 100°C and a steam pressure of 0.4 MPa, high-temperature steam treatment for 60 minutes, and then cooling to obtain pretreated slag; mixing the pretreated slag with a 75% volume fraction of ethanol aqueous solution at a solid-liquid ratio of 1:7, and performing ultrasonic treatment at an ultrasonic frequency of 50 kHz and an ultrasonic power density of 0.1 W / cm 2 , the extraction temperature is 25°C, and the extraction time is 40 minutes; after the extraction, the solid-liquid centrifugation is carried out at a speed of 2000r / min for 20 minutes to obtain a preliminary detoxification residue; the preliminary detoxification residue is mixed with a solution of a composite enzyme and then subjected to enzymatic hydrolysis at a temperature of 35°C and a pH value of 5 for 7 hours, followed by filtration to obtain a deep detoxification residue; the composite enzyme includes cellulase, ligninase and pyrethroid degrading enzyme in a mass ratio of 1:1:1; the amount of the composite enzyme added is 0.2% of the mass of the preliminary detoxification residue;

[0057] Comparative Example 5

[0058] This comparative example provides a method for recycling by-products of refined pyrethroids, which differs from Example 1 in that: (3) Drying treatment: the deep detoxification residue is first subjected to low-temperature vacuum drying at a vacuum degree of -0.05 MPa and a drying temperature of 60°C for 3 hours, and then subjected to hot air drying at a temperature of 110°C for 90 minutes to obtain a pretreated residue.

[0059] Experimental Example 1

[0060] The biomass particles provided in Examples 1-6 and Comparative Examples 1-5 were tested for residual pyrethroid concentration:

[0061] (1) Sample pretreatment: Extraction: Weigh 5.0 g of the treated by-product sample, add 50 mL of ethyl acetate, and extract on an oscillator at 200 rpm for 30 min. Repeat the extraction twice and combine the extracts. Purification: Pass the extract through an anhydrous sodium sulfate column (5 g of anhydrous sodium sulfate) to remove water, concentrate by rotary evaporation to near dryness, dilute to 1.0 mL with n-hexane, filter through a 0.22 μm filter membrane, and wait for detection on the machine.

[0062] (2) Gas chromatography-mass spectrometry instrument parameters: Chromatographic column: DB-5MS capillary column (30 m × 0.25 mm × 0.25 μm); Heating program: initial temperature 60 °C, hold for 1 min, increase to 200 °C at 20 °C / min, then increase to 280 °C at 5 °C / min, hold for 5 min; Inlet temperature: 280 °C, splitless injection, injection volume 1 μL; Mass spectrometry conditions: electron bombardment source, ion source temperature 230 °C, scan range 50-500 m / z, selected ion monitoring mode, monitoring pyrethroid characteristic ions.

[0063] (3) Quantitative method: External standard method: Use pyrethroid standard (purity ≥99.5%) to prepare a standard curve of 0.01, 0.1, 1, 10, and 50 μg / mL, and plot the standard curve using peak area versus concentration.

[0064] (4) The test results are shown in Table 1:

[0065] Table 1

[0066]

[0067] The results in Table 1 show that the method for recycling the by-products of refined pyrethroids provided in Examples 1-6 of this application can produce biomass pellets in which the concentration of residual pyrethroids is significantly lower than the national standard limit (GB 2763-2021 National Food Safety Standard Maximum Residue Limits of Pesticides in Food).

[0068] Experimental Example 2

[0069] (1) Cellulose / hemicellulose degradation rate

[0070] Detection method: acid hydrolysis-high performance liquid chromatography (HPLC) method.

[0071] Procedure: Weigh 2 g of each of the biomass particles provided in Examples 1-6 and Comparative Examples 1-5, add 20 mL of 72% H2SO4 and hydrolyze at room temperature for 1 h, dilute to a sulfuric acid concentration of 4%, cook at 121°C for 1 h, and centrifuge to obtain the supernatant.

[0072] Detection: HPLC (Agilent 1260) equipped with a differential refractive index detector (RID) was used to determine the contents of glucose (cellulose hydrolysis product) and xylose (hemicellulose hydrolysis product).

[0073] Calculation: Degradation rate (%) = (1-total sugar content of raw materials + residual sugar content) × 100%

[0074] (2) Lignin removal rate

[0075] Detection method: ultraviolet spectrophotometry (UV).

[0076] Procedure: After the biomass pellet samples provided in Examples 1-6 and Comparative Examples 1-5 were acid hydrolyzed, the residue was refluxed with a dioxane-sulfuric acid solution (volume ratio 9:1) to extract lignin. After centrifugation, the supernatant was collected and the absorbance was measured at 205 nm. The quantification was performed according to the standard curve.

[0077] Calculation: Removal rate (%) = (1-raw material lignin content residual lignin content) × 100%

[0078] (3) Test results: Cellulose degradation rate (%), hemicellulose degradation rate (%) and lignin removal rate (%) are shown in Table 2:

[0079] Table 2

[0080] Group number Cellulose degradation rate (%) Hemicellulose degradation rate (%) Lignin removal rate (%) Example 1 92％ 94％ 81％ Example 2 91％ 93％ 80％ Example 3 90％ 93％ 80％ Example 4 96％ 99％ 84％ Example 5 95％ 98％ 83％ Example 6 96％ 98％ 84％ Comparative Example 1 82％ 83％ 65％ Comparative Example 2 85％ 90％ 71％ Comparative Example 3 84％ 88％ 70％ Comparative Example 4 82％ 87％ 73％ Comparative Example 5 85％ 88％ 74％

[0081] The results in Table 2 show that the method for recycling the by-products of the refined pyrethroid products provided in Examples 1-6 of the present application has excellent cellulose degradation rate, hemicellulose degradation rate and lignin removal rate, indicating that the efficiency of converting the by-products into biomass energy is high, far exceeding the utilization rate of traditional single combustion or landfill.

[0082] In summary, the method for recycling byproducts of refined pyrethroid products provided by the present invention can convert the biomass components in the solid residues produced after pyrethroid extraction into biomass energy, thereby solving the problem of byproduct disposal and reducing environmental pollution while also achieving resource recycling and creating economic value.

[0083] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for recycling by-products of refined pyrethroids, characterized by: include: (1) By-product collection: collecting the solid residue after pyrethroid extraction, removing foreign matter, and crushing the solid residue to obtain crushed residue; (2) Detoxification treatment: placing the slag in a high-temperature steam treatment machine at a temperature of 120-150° C. and a steam pressure of 0.15-0.3 MPa, and performing high-temperature steam treatment for 30-40 minutes, followed by cooling to obtain pretreated slag; The pretreated residue is mixed with an ethanol aqueous solution having a volume fraction of 60-70%, followed by ultrasonic extraction; after the extraction, the solid and liquid are centrifuged to obtain a preliminary detoxified residue; the preliminary detoxified residue is mixed with a solution of a composite enzyme, followed by enzymatic hydrolysis, and then filtered to obtain a deep detoxified residue; the composite enzyme comprises cellulase, ligninase, and pyrethroid degrading enzyme in a mass ratio of 1:1:1; (3) Drying: Drying the deep detoxification residue to obtain a pre-treated residue; (4) Preparation of biomass particles: the pre-treated residue is added with auxiliary materials and then extruded into granules, and the biomass particles are obtained after cooling and screening.

2. The method for recycling by-products of refined pyrethroids according to claim 1, characterized in that: In step (2), the conditions for ultrasonic extraction include: the solid-liquid ratio of the pretreated residue to the ethanol aqueous solution is 1:4-6, the ultrasonic frequency is 20-40kHz, and the ultrasonic power density is 0.2-0.5W / cm 2 , the extraction temperature is 30-40℃, and the extraction time is 20-30min.

3. The method for recycling by-products of refined pyrethroid products according to claim 1, characterized in that: In step (2), the conditions for centrifugal separation include: a rotation speed of 3000-4000 r / min and a time of 10-15 min.

4. The method for recycling by-products of refined pyrethroid products according to claim 1, characterized in that: In step (2), the enzymatic hydrolysis conditions include: the addition amount of the complex enzyme is 0.5-1.0% of the mass of the preliminary detoxification residue, the enzymatic hydrolysis temperature is 40-50° C., the pH value is 5.5-6.5, and the enzymatic hydrolysis time is 4-6 hours.

5. The method for recycling by-products of refined pyrethroid products according to claim 1, characterized in that: In step (3), the deep detoxification residue is first subjected to low-temperature vacuum drying and then to hot air drying.

6. The method for recycling by-products of refined pyrethroid products according to claim 5, characterized in that: The conditions for low-temperature vacuum drying include: vacuum degree of -0.08 to -0.10 MPa, drying temperature of 40-50° C., and drying for 1-2 hours.

7. The method for recycling by-products of refined pyrethroids according to claim 5, characterized in that: The conditions for hot air drying include: temperature of 80-100°C and drying for 30-60 minutes.

8. The method for recycling by-products of refined pyrethroids according to claim 1, characterized in that: In step (4), the preparation of biomass particles includes: adding 2-5% starch to the pretreatment residue, mixing and spraying water to obtain a mixture, wherein the water content of the mixture is 12-15%; feeding the mixture into a ring die pelletizer at a rotation speed of 80-120 r / min and a roller pressure of 5-8 MPa for extrusion granulation; then cooling through a countercurrent cooler, the cooling medium is room temperature air, cooling for 10-15 minutes, and the cooled particles are screened through a vibrating screen to obtain the biomass particles.

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