Preparation method and application of pyrolysis residue-based molecular sieve

Abstract

The application discloses a preparation method and application of a pyrolysis residue-based molecular sieve and belongs to the technical field of molecular sieve preparation. The pyrolysis residue of oil-containing sludge is used as a main silicon-aluminum source, and the molecular sieve is prepared through the following steps: crushing and screening, calcination at 450-650 DEG C, acid washing and impurity removal, low-temperature alkali fusion at 300-550 DEG C, adjustment of the molar ratio of SiO2 / Al2O3 to 20-80, hydrothermal crystallization at 140-180 DEG C, and calcination at 500-600 DEG C. The molecular sieve prepared by the method has high crystallinity, large specific surface area and moderate acidity. The molecular sieve is used for catalytic pyrolysis of organic solid waste, and the pyrolysis oil yield, the proportion of light components and the calorific value of pyrolysis gas can be remarkably improved, the generation amount of heavy tar is reduced, and the recycling performance of the catalyst is good. The application realizes the three benefits of hazardous waste reduction, green synthesis and high-value utilization of organic solid waste, has low cost, environmental protection and excellent performance, and has outstanding creativity and industrialization prospect.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve preparation technology, and in particular to a method for preparing and applying a pyrolysis residue-based molecular sieve. Background Technology

[0002] Oily sludge is a major solid waste generated during petroleum extraction, transportation, and refining. Pyrolysis can recover oil and reduce its volume. However, pyrolysis of oily sludge produces a large amount of pyrolysis residue, mainly composed of SiO2, Al2O3, and small amounts of metal oxides such as iron, calcium, and magnesium, possessing both silicon and aluminum source properties. Current technologies mostly use it in roadbed materials, building material fillers, or wastewater adsorbents, rarely applying it to the catalysis field, resulting in low resource utilization and low added value.

[0003] Molecular sieves, due to their regular pore structure and tunable acidic sites, are widely used in petrochemicals, biomass pyrolysis, and other fields. Traditional molecular sieve synthesis relies on chemical silicon sources (such as silica sol and water glass) and aluminum sources (such as sodium aluminate), resulting in high costs and significant carbon emissions. While the preparation of molecular sieves using industrial solid waste (such as coal gangue, fly ash, and red mud) as raw materials has been reported, these methods generally suffer from insufficient silicon-aluminum activation and inadequate catalytic activity. Furthermore, most existing technologies employ high-temperature alkaline fusion (800-900℃) to completely destroy the inert crystalline phase, which is energy-intensive and can damage the potential nano-ordered structures in the solid waste. Additionally, the preparation of most traditional high-performance molecular sieves relies on organic template agents, which play a structure-guiding role in the synthesis process, but their high cost contributes to the high production cost of molecular sieves.

[0004] Therefore, it is of great significance to develop a new technology that uses oily sludge pyrolysis residue as a silicon-aluminum source, combines it with other processes to produce low-cost, high-performance molecular sieves, and applies them to the catalytic pyrolysis of organic solid waste. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing and applying a molecular sieve based on pyrolysis residue. This preparation process can realize a closed loop of "hazardous waste reduction - green synthesis of molecular sieve - high-value utilization of organic solid waste". Moreover, no organic template is required during the preparation process. The molecular sieve obtained can be used as a catalyst for the catalytic pyrolysis of organic solid waste, which can improve the yield of pyrolysis oil, the proportion of light components and the calorific value of pyrolysis gas.

[0006] To achieve the above objectives, the present invention provides a method for preparing pyrolysis residue-based molecular sieves, comprising the following steps: (1) Pretreatment and calcination: The oily sludge pyrolysis residue is crushed, screened, and calcined at 450-650℃; (2) Pickling to remove impurities: The residue obtained in step (1) is mixed with inorganic acid at a solid-liquid ratio of 1:(5-12), stirred and leached at 60-90℃, and then washed and dried to obtain pickled material; (3) Alkali fusion activation: The pickling material and solid alkali are mixed at a mass ratio of 1:(0.8-2.0) and alkali fusion is carried out at 300-550℃ to obtain alkali fused clinker; (4) Hydrothermal crystallization: Adjust the molar ratio of SiO2 / Al2O3 in the alkali-fused clinker to (20-80):1, then mix the alkali-fused clinker with deionized water to form a gel, and carry out hydrothermal crystallization at 140-180℃. (5) Post-treatment: After washing and drying, calcination is carried out at 500-600℃ to obtain pyrolysis residue-based molecular sieve.

[0007] Preferably, in step (2), the inorganic acid is hydrochloric acid or sulfuric acid, with a concentration of 1-3 mol / L.

[0008] Preferably, in step (3), the solid alkali is at least one of NaOH and KOH.

[0009] Preferably, in step (4), the SiO2 / Al2O3 molar ratio is adjusted by first measuring the SiO2 and Al2O3 content in the alkali-melted clinker. If the measured value is lower than 20, a silicon source is added; if it is higher than 80, an aluminum source is added.

[0010] Preferably, the aluminum source is at least one of sodium aluminate, aluminum sulfate, aluminum isopropoxide, and boehmite; and the silicon source is at least one of water glass, silica sol, silica, and tetraethyl orthosilicate.

[0011] Preferably, in step (4), the alkali-melted clinker and deionized water are mixed at a solid-liquid ratio of 1:(8-20).

[0012] The present invention also provides the application of a pyrolysis residue-based molecular sieve prepared by the above preparation method as a catalyst in the catalytic pyrolysis of organic solid waste.

[0013] Preferably, the organic solid waste is at least one of oily sludge, waste plastics, waste rubber, agricultural and forestry waste, and municipal sludge.

[0014] Preferably, the amount of molecular sieve added is 1%-10% of the mass of organic solid waste.

[0015] Preferably, the temperature for catalytic pyrolysis is 450-700℃ and the time is 30-120 min.

[0016] The pyrolysis residue of oily sludge is rich in SiO2 and Al2O3, but exists in inert crystalline phases (quartz, feldspar) or glass. After calcination to remove residual carbon, acid washing can dissolve most of the amorphous impurities (Fe2O3, CaO, etc.) while exposing the active sites of silicon and aluminum. Low-temperature alkali melting gently destroys the inert crystalline phases, generating soluble silicates and aluminates, while retaining some nano-sized ordered silicon and aluminum structures. Finally, during hydrothermal crystallization, OH... - This process promotes the dissolution and depolymerization of amorphous active silica-alumina components in alkali-fused clinker, forming mobile active monomers. These active monomers preferentially deposit and arrange themselves on the previously retained micro-ordered structures, ultimately achieving self-assembly into molecular sieves with regular microporous structures. At the same time, no expensive artificial template agents are required in this self-directed process, saving costs.

[0017] The resulting molecular sieve possesses regular micropores and suitable acidic sites. During the catalytic pyrolysis of organic solid waste, its micropores act like sieves, allowing only appropriately sized molecules to pass through, breaking down large oil molecules into more valuable light oils. The acidic sites promote key reactions such as deoxygenation and aromatization, increasing the proportion of combustible components like hydrogen and methane in the pyrolysis gas, while simultaneously inhibiting the formation of carbon deposit precursors. Therefore, the pyrolysis oil yield is higher, the light components are more abundant, the calorific value of the pyrolysis gas is significantly improved, while heavy tar and carbon deposits are reduced, and the catalyst is more durable.

[0018] Therefore, the present invention provides a method for preparing and applying a pyrolysis residue-based molecular sieve. By using a low-temperature alkaline fusion process, the ordered nanoscale silicon-aluminum structure in solid waste is preserved, and self-directed crystallization is achieved. This method breaks through the technical bottleneck of traditional solid waste-based molecular sieve preparation, which requires high temperature and high energy consumption and relies on expensive organic template agents. This method not only transforms hazardous waste residue into high-value-added molecular sieves, realizing a closed-loop resource utilization of "waste-to-waste", but also significantly reduces synthesis costs and carbon emissions. The prepared molecular sieve has excellent shape-selective catalysis and anti-carbon deposition properties, and can significantly improve the yield and calorific value of light oil products in the catalytic pyrolysis of organic solid waste.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 Bar charts showing the comparison of pyrolysis oil yields from different embodiments and comparative examples of catalytic oily sludge pyrolysis. Detailed Implementation

[0021] This invention provides a method for preparing pyrolysis residue-based molecular sieves, specifically including the following steps: (1) Pretreatment and calcination: The oily sludge pyrolysis residue is crushed and screened, and calcined at 450-650℃ for 1.5-4 hours to remove residual carbon, volatile matter and sulfides, and obtain activated precursor.

[0022] (2) Pickling to remove impurities: Mix the residue obtained in step (1) with inorganic acid at a solid-liquid ratio of 1:(5-12), stir and leach at 60-90℃ for 1-3 hours to remove metal impurities such as iron, calcium, and magnesium, and obtain pickled material after washing and drying.

[0023] In this invention, the inorganic acid is hydrochloric acid or sulfuric acid with a concentration of 1-3 mol / L. Furthermore, the waste liquid generated from acid washing can be treated by neutralization and precipitation: lime slurry is added to adjust the pH to 8-9, allowing Fe... 3+ Ca 2+ Mg 2+ After hydroxide precipitate forms, the solution is separated by pressure filtration. The filtrate is then evaporated and crystallized to separate inorganic salt byproducts (such as NaCl / CaCl2). The condensate generated during evaporation is reused for pickling solution preparation, achieving green discharge treatment of waste liquid. If sulfuric acid is used, the waste liquid can be reused after precipitation and filtration or neutralized before discharge.

[0024] (3) Alkali fusion activation: The pickling material and solid alkali are mixed at a mass ratio of 1:(0.8-2.0) and alkali fused at 300-550℃ for 1-3 hours to destroy the glassy phase of the residue and convert the silica and aluminum into soluble silicates and aluminates, while partially retaining the nanoscale ordered domains of silica and aluminum in the residue, thus obtaining alkali-fused clinker. The solid alkali is at least one of NaOH and KOH.

[0025] (4) Hydrothermal crystallization: Adjust the molar ratio of SiO2 / Al2O3 in the alkali-fused clinker to (20-80):1, then mix the alkali-fused clinker with deionized water at a solid-liquid ratio of 1:(8-20) to form a gel, and carry out hydrothermal crystallization at 140-180℃ for 12-48 hours.

[0026] In this invention, the SiO2 / Al2O3 molar ratio is adjusted as follows: First, the SiO2 and Al2O3 contents in the alkali-fused clinker are measured. If the measured value is lower than 20, a silicon source is added; if it is higher than 80, an aluminum source is added. The aluminum source is at least one of sodium aluminate, aluminum sulfate, aluminum isopropoxide, and boehmite; the silicon source is at least one of water glass, silica sol, silica fume, and tetraethyl orthosilicate.

[0027] (5) Post-treatment: After washing and drying, calcination is carried out at 500-600℃ for 3-6 hours to obtain pyrolysis residue-based molecular sieve.

[0028] The molecular sieve prepared by the above method can be used as a catalyst for the catalytic pyrolysis of organic solid waste under an inert atmosphere (nitrogen or argon) and at 450-700℃, thereby improving the pyrolysis oil yield, the proportion of light components, the calorific value of pyrolysis gas, and reducing the amount of heavy tar generated. The organic solid waste includes at least one of oily sludge, waste plastics, waste rubber, agricultural and forestry waste, and municipal sludge, and the amount of molecular sieve added is 1%-10% of the mass of the organic solid waste.

[0029] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. Furthermore, it should be understood that after reading the contents of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims and are all within the protection scope of the present invention.

[0030] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0031] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0032] Unless otherwise specified, the reagents, instruments, and equipment used in this invention are all commonly used by those skilled in the art, and the testing standards all use national or international standards commonly used in the field, without further explanation.

[0033] Example This embodiment provides a method for preparing pyrolysis residue-based molecular sieves, specifically including the following steps: (1) Pretreatment and calcination: Take the pyrolysis residue of oily sludge from an oil field (containing 48.3wt% SiO2, 15.6wt% Al2O3, 6.2wt% Fe2O3, and 4.5wt% CaO), grind it through a 150-mesh sieve, and calcine it in a muffle furnace at 550℃ for 2 hours.

[0034] (2) Acid washing to remove impurities: Add 2 mol / L hydrochloric acid to the calcined residue at a solid-liquid ratio of 1:8, stir and acid wash at 80℃ for 2 hours, filter and wash until neutral, and dry at 110℃.

[0035] The pickling waste liquid is neutralized to pH 8.5 with lime milk, the precipitate is filtered under pressure, the filtrate is evaporated and crystallized to obtain NaCl, and the condensate is reused.

[0036] (3) Alkali fusion activation: The acid-washed and dried material is mixed and ground with NaOH at a mass ratio of 1:1.2, alkali fusion is carried out at 450℃ for 2 hours, and then cooled to obtain alkali fused clinker.

[0037] (4) Hydrothermal crystallization: The molar ratio of SiO2 / Al2O3 in the alkali-fused clinker was found to be high. Sodium aluminate was added to make the final Si / Al=40. The alkali-fused clinker and deionized water were mixed at a solid-liquid ratio of 1:12 and stirred to form a gel. The gel was then transferred to a reaction vessel and crystallized at 160°C for 24 hours.

[0038] (5) Post-processing: The crystallized product was filtered and washed until pH=7.5, dried at 110℃, and calcined at 550℃ for 4 hours to obtain a white powdered molecular sieve. The XRD pattern of the obtained molecular sieve was consistent with the ZSM-5 standard pattern.

[0039] Example 2 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the alkali melting temperature in step (3) is 550°C, while the rest is the same as in Example 1.

[0040] Example 3 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the alkali melting temperature in step (3) is 350°C, while the rest is the same as in Example 1.

[0041] Example 4 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the alkali melting time in step (3) is 3 hours, while the rest is the same as in Example 1.

[0042] Example 5 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Embodiment 1 is that the hydrothermal crystallization temperature in step (4) is 150°C, while the rest are the same as in Embodiment 1.

[0043] Example 6 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Embodiment 1 is that the hydrothermal crystallization temperature in step (4) is 180°C, while the rest is the same as in Embodiment 1.

[0044] Example 7 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Embodiment 1 is that the hydrothermal crystallization time in step (4) is 36 hours, while the rest are the same as in Embodiment 1.

[0045] Example 8 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the final Si / Al molar ratio is adjusted to 60 in step (4), while the rest is the same as in Example 1.

[0046] Example 9 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Embodiment 1 is that NaOH is replaced with KOH in step (3), while the rest is the same as in Embodiment 1.

[0047] Example 10 This embodiment provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the concentration of hydrochloric acid in step (2) is 1 mol / L, while the rest are the same as in Example 1.

[0048] Comparative Example 1 This comparative example provides a raw pyrolysis residue that has not undergone any treatment and is used directly for comparison without going through the preparation steps of this invention.

[0049] Comparative Example 2 This comparative example provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that step (2) acid washing to remove impurities is omitted, while the rest is the same as in Example 1.

[0050] Comparative Example 3 This comparative example provides a method for preparing a pyrolysis residue-based molecular sieve. The difference between this method and Example 1 is that the calcination temperature in step (1) is 350°C, while the rest are the same as in Example 1.

[0051] Comparative Example 4 This comparative example provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the alkali melting temperature in step (3) is 200°C, while the rest are the same as in Example 1.

[0052] Comparative Example 5 This comparative example provides a method for preparing a pyrolysis residue-based molecular sieve. The difference between this method and Example 1 is that the alkali melting temperature in step (3) is 800°C, while the rest is the same as in Example 1.

[0053] Comparative Example 6 This comparative example provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the hydrothermal crystallization temperature in step (4) is 100°C, while the rest are the same as in Example 1.

[0054] Comparative Example 7 This comparative example provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the hydrothermal crystallization temperature in step (4) is 220°C, while the rest are the same as in Example 1.

[0055] Comparative Example 8 This comparative example provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that the final Si / Al molar ratio is adjusted to 120 in step (4), while the rest is the same as in Example 1.

[0056] Comparative Example 9 This comparative example provides a method for preparing a pyrolysis residue-based molecular sieve. The difference from Example 1 is that step (3) alkaline fusion activation is omitted, and the pickled material from step (2) is directly subjected to step (4) hydrothermal crystallization. The rest is the same as Example 1.

[0057] The molecular sieves prepared in the above examples and comparative examples were subjected to the following performance tests, and the results are shown in Table 1.

[0058] (1) Molecular sieve crystallinity test: X-ray diffractometer (XRD, Cu Kα radiation, λ=0.15406nm, scanning range 2θ=5°~50°) was used. The relative crystallinity was calculated by comparing the sum of the characteristic peak intensities of the sample at 2θ=7.9°, 8.8°, 23.1°, 23.9°, and 24.4° with that of the reference sample.

[0059] (2) Specific surface area test: Nitrogen adsorption-desorption (BET) method was used at 77K. The sample was degassed at 300℃ for 4 hours. The specific surface area was calculated by multi-point BET equation.

[0060] (3) Acidity: The acidity of the molecular sieve was determined using the ammonia-programmed temperature desorption method. Before testing, the sample was pretreated in a helium atmosphere at 550℃ for 1 hour to remove adsorbed moisture and impurities. After cooling to 100℃, ammonia was introduced for adsorption for 30 minutes until saturation, and then helium was used for purging for 1 hour to remove physically adsorbed ammonia. The temperature was programmed to rise from 100℃ to 700℃ at a rate of 10℃ / min, and the desorption curve was recorded using a thermal conductivity detector (TCD). Based on the NH3 desorption peak area, the acidity per unit mass of molecular sieve was calculated by using a standard curve or a reference sample with known acidity.

[0061] Table 1: Characterization results of molecular sieves prepared in different examples and comparative examples

[0062] Table 1 shows that different preparation parameters have a significant impact on the crystallinity, specific surface area, and acidity of the molecular sieve. Among them, Example 4 yielded the highest relative crystallinity of 85% and a specific surface area of ​​340 m². 2 / g and acid content 0.50 mmol / g; however, whether the acid washing, alkali fusion, calcination, alkali fusion or improper hydrothermal temperature are omitted, the crystallinity decreases significantly or there is no crystal phase, indicating that the process parameters defined in this invention are synergistic and necessary.

[0063] The molecular sieves prepared in the above examples and comparative examples were added at 5 wt% to oily sludge from the same source as the preparation residue, mixed thoroughly, and pyrolyzed in a tube furnace at 550°C under a N2 atmosphere for 30 min. The following data tests were performed, and the results are as follows: Figure 1 As shown in Table 2.

[0064] (1) Pyrolysis oil yield: After the pyrolysis reaction is completed, the liquid product in the condensation device is collected and weighed. Pyrolysis oil yield (%) = (mass of pyrolysis oil / dry weight of organic solid waste) × 100%.

[0065] (2) Proportion of light components: The mass fraction of the pyrolysis oil with a boiling point below 300℃ was determined by atmospheric distillation.

[0066] (3) Composition and calorific value of pyrolysis gas: The volume fractions of H2, CH4, CO, and CO2 were analyzed by gas chromatography (TCD detector, Porapak Q and molecular sieve 5A column). The calorific value was calculated based on the volume fraction of each component and its calorific value coefficient: Calorific value (MJ / m³) 3 =Σ(component volume fraction × component calorific value).

[0067] (4) Reduction rate of heavy tar: Heavy tar is defined as the fraction with a boiling point above 450℃. Reduction rate (%) = (Heavy tar content of blank group - Heavy tar content of experimental group) / Heavy tar content of blank group × 100%.

[0068] Table 2: Performance of catalytic oily sludge pyrolysis in different embodiments and comparative examples

[0069] Depend on Figure 1 As shown in Table 2, the molecular sieve catalytic pyrolysis of oily sludge prepared in the embodiments of the present invention significantly outperforms the blank group and the comparative group in terms of pyrolysis oil yield, proportion of light components, calorific value of pyrolysis gas, and reduction rate of heavy tar. Example 4 exhibits the best performance, while the catalytic effect of the samples prepared in the comparative group, which deviate from the parameter range of the present invention, is significantly reduced, further verifying the rationality of the process parameters.

[0070] (5) Catalyst recycling performance: The catalysts used in Examples 1, 2 and 4 were regenerated by calcining in air at 550°C for 2 hours. The pyrolysis experiment was repeated, and the ratio of the yield of the third pyrolysis oil to the yield of the first pyrolysis was recorded. The results are shown in Table 3.

[0071] Table 3: Catalyst Recycling Performance

[0072] As shown in Table 3, the molecular sieve of the present invention has good recyclability, indicating that the catalyst has strong resistance to carbon deposition and stable structure.

[0073] The molecular sieves prepared in Examples 1, 4, and 7 were added to other organic solid wastes at 5 wt% of the organic solid waste mass. The pyrolysis temperature of waste plastics, agricultural and forestry waste, and municipal sludge was 550℃ and the residence time was 60 min. The pyrolysis temperature of waste rubber was 600℃ and the residence time was 90 min. All were carried out under a nitrogen atmosphere. After pyrolysis, the condensed liquid products were collected. The oil phase was separated by dichloromethane extraction and weighed to calculate the pyrolysis oil yield. The proportion of light components was determined by simulated distillation. The composition of pyrolysis gas was analyzed by gas chromatography and the calorific value was calculated. The reduction rate of heavy tar was calculated by comparison with a blank group without catalyst. The results are shown in Tables 4-7.

[0074] Table 4: Catalytic Pyrolysis of Waste Polyethylene Plastics

[0075] Table 5: Catalytic Pyrolysis of Waste Tire Rubber

[0076] Table 6: Catalytic pyrolysis of corn stalks (agricultural and forestry waste)

[0077] Table 7: Catalytic Pyrolysis of Municipal Sludge

[0078] As shown in Tables 4-7, the molecular sieve prepared by this invention has a significant catalytic upgrading effect on different types of organic solid waste, indicating that the molecular sieve of this invention has wide applicability and excellent catalytic performance.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a pyrolysis residue-based molecular sieve, characterized in that, Includes the following steps: (1) Pretreatment and calcination: The oily sludge pyrolysis residue is crushed, screened, and calcined at 450-650℃; (2) Pickling to remove impurities: The residue obtained in step (1) is mixed with inorganic acid at a solid-liquid ratio of 1:(5-12), stirred and leached at 60-90℃, and then washed and dried to obtain pickled material; (3) Alkali fusion activation: The pickling material and solid alkali are mixed at a mass ratio of 1:(0.8-2.0) and alkali fusion is carried out at 300-550℃ to obtain alkali fused clinker; (4) Hydrothermal crystallization: Adjust the molar ratio of SiO2 / Al2O3 in the alkali-fused clinker to (20-80):1, then mix the alkali-fused clinker with deionized water to form a gel, and carry out hydrothermal crystallization at 140-180℃. (5) Post-treatment: After washing and drying, calcination is carried out at 500-600℃ to obtain pyrolysis residue-based molecular sieve.

2. The method for preparing a pyrolysis residue-based molecular sieve according to claim 1, characterized in that, In step (2), the inorganic acid is hydrochloric acid or sulfuric acid, with a concentration of 1-3 mol / L.

3. The method for preparing a pyrolysis residue-based molecular sieve according to claim 1, characterized in that, In step (3), the solid alkali is at least one of NaOH and KOH.

4. The method for preparing a pyrolysis residue-based molecular sieve according to claim 1, characterized in that, In step (4), the SiO2 / Al2O3 molar ratio is adjusted as follows: first, the SiO2 and Al2O3 content in the alkali-melted clinker is measured. If the measured value is lower than 20, silicon source is added; if it is higher than 80, aluminum source is added.

5. The method for preparing a pyrolysis residue-based molecular sieve according to claim 4, characterized in that, The aluminum source is at least one of sodium aluminate, aluminum sulfate, aluminum isopropoxide, and boehmite; the silicon source is at least one of water glass, silica sol, silica, and tetraethyl orthosilicate.

6. The method for preparing a pyrolysis residue-based molecular sieve according to claim 1, characterized in that, In step (4), the alkali-fused clinker and deionized water are mixed at a solid-liquid ratio of 1:(8-20).

7. An application of a pyrolysis residue-based molecular sieve, characterized in that, The molecular sieve is prepared by the preparation method according to any one of claims 1-6, and the molecular sieve is used as a catalyst for the catalytic pyrolysis of organic solid waste.

8. The application of the pyrolysis residue-based molecular sieve according to claim 7, characterized in that, Organic solid waste includes at least one of the following: oily sludge, waste plastics, waste rubber, agricultural and forestry waste, and municipal sludge.

9. The application of the pyrolysis residue-based molecular sieve according to claim 7, characterized in that, The amount of molecular sieve added is 1%-10% of the mass of organic solid waste.

10. The application of the pyrolysis residue-based molecular sieve according to claim 7, characterized in that, The temperature for catalytic pyrolysis is 450-700℃, and the time is 30-120 min.

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