Preparation method of composite molecular sieve for in-situ conversion of medium-low-maturity oil shale

Abstract

The invention discloses a preparation method of a composite molecular sieve for in-situ conversion of medium-low-maturity oil shale, which comprises the following steps: S1, activating industrial tailings, adding an acid solution, and aging to form a mixture A; s2, treating a mixture of a metal compound and an organic polymer with a phytic acid solution to obtain a mixture B; s3, mixing the mixture A, the mixture B, a phosphorus source, a silicon source, a template agent and water, uniformly stirring to obtain a mixture C, crystallizing the mixture C in a closed reaction kettle, and filtering and washing a product to obtain the composite molecular sieve. The method solves the problem of poor performance and stability of the existing in-situ conversion catalyst or material, improves the stability of the in-situ conversion catalytic material, and lays a foundation for reducing in-situ conversion activation energy and promoting hydrocarbon generation.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst molecular sieves, and particularly relates to a preparation method of a composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale. Background Art

[0002] The situation of China's oil supply security is severe. With the increasing difficulty of newly discovered large-scale oil reserves, the decline in the oil production quality of old oil fields, and the foreign oil dependence as high as over 71%, finding a replacement area for oil resources, ensuring stable or even increased crude oil production, and reducing the foreign oil dependence have become an urgent need to ensure national energy security. Among various oil resources, shale oil has the advantage of large recoverable reserves (nearly 3 times the total amount of conventional oil resources), making shale oil the most potential replacement resource. The resource potential of in-situ conversion of shale oil underground mainly depends on the hydrocarbon generation potential of the untransformed organic matter in the shale formation and the amount of retained hydrocarbons that have been generated but not expelled. Medium- and low-maturity, high-abundance shale is an ideal object for in-situ conversion. By comparing and analyzing the hydrocarbon generation and conversion potential of shale organic matter with different thermal evolution degrees in three regions of China, the United States, and Jordan, generally, it decreases with the increase of the Ro value. With the increase of the thermal evolution degree, the organic matter in the shale is gradually converted into hydrocarbon substances, and the amount of retained hydrocarbons shows a trend of increasing first and then decreasing. Among them, the amount of retained liquid hydrocarbons is the largest in the stage where the Ro value is 0.5% - 1.0%, and the proportion of untransformed organic matter is relatively large. Therefore, it is the best maturity window for in-situ conversion of shale.

[0003] According to the method of obtaining shale oil, it can be divided into surface retorting and in-situ underground conversion. Compared with surface retorting, in-situ underground conversion has advantages such as less pollution and stable yield. Among them, the design and performance of the catalyst in the hydrothermal cracking catalytic viscosity reduction technology are the most important and crucial part of this technology. Due to the relatively small amount of catalyst used, low cost, the characteristics of being able to be used in combination or having various combinations of ligands and central metals in terms of structure, it determines that it has strong plasticity, great development potential, and wide selectivity. Generally, oil shale resources with a burial depth of less than 300m can be mined by open-pit mining and transported to a retorting plant to extract shale oil; while oil shale with a burial depth of more than 300m is suitable for in-situ heating of the oil shale formation to convert it into shale oil for mining. Currently, the retorting oil production technology for in-situ conversion of oil shale is the most mature with the ICP (In-suit Conversion Process) technology of Shell Oil Company.

[0004] Compared with the above-ground retorting technology, in-situ conversion mining can obtain shale oil without excavating underground oil shale ore to the surface. However, during the conversion process, the oil shale layer needs to be heated to a high temperature of 500 °C to pyrolyze and obtain shale oil, resulting in huge energy consumption. The derived rate of large molecular hydrocarbons is slow, and the organic matter is prone to coking and secondary cracking, reducing the conversion rate and extraction rate of oil in the oil shale. However, if a catalyst is added during the in-situ conversion process, the catalyst will significantly change the activation energy in the reaction process, thereby changing the reaction rate and accelerating the reaction. Reducing the temperature required for in-situ oil and gas conversion of oil shale and improving the quality of oil and gas products by adding a catalyst have become important research and development directions for the industrialization of in-situ conversion of oil shale.

[0005] CN202210225272.6 discloses a needle-like nano iron-based double metal hydroxide and its application method for regulating the selectivity of oil shale pyrolysis products at low temperature. The metal cations in its lamellar structure are composed of Fe 3+ and one divalent metal cation selected from Ni 2+ , Mn 2+ and Co 2+ . The anions in its interlayer region are composed of OH - , CO 3 2- and OCN -Composition. Although this patent can achieve the catalytic pyrolysis of oil shale, it has the deficiencies of a single functional component of the catalyst and the lack of obvious effect of adding metal compounds on improving the component distribution of pyrolysis products. CN202210181054.7 details a rare earth mesoporous molecular sieve and its catalyst preparation method applied to the catalytic cracking of oil shale. The pore diameter of the rare earth mesoporous molecular sieve is 3 - 7 nm; the catalyst includes a rare earth mesoporous molecular sieve, quaternary ammonium base, supported metal nano-alumina, cyclohexane ethyl acetate, and surfactant. Although the catalyst of the present invention can accelerate the process of kerogen conversion to oil and gas and reduce the cracking conversion temperature of oil shale, it has problems such as a cumbersome preparation process and poor compatibility of each component. CN1326974C discloses a catalyst prepared by mixing cobalt naphthenate, ethylene glycol monomethyl ether, acidified activated clay, glycerol monostearate, and chlorinated paraffin in different ratios. By heating and retorting oil shale at 510 - 550 °C, it effectively reduces the cost of producing light fuel oil from oil-bearing rocks and improves the quality of light fuel oil products. CN101962559A also discloses a catalyst prepared by mixing cobalt naphthenate, ethylene glycol monomethyl ether, acidified activated clay, glycerol monostearate, and chlorinated paraffin in different ratios. The catalyst is added to oil shale in two steps before and after. The total amount of the added catalyst is 0.8 - 2% of the weight of oil shale ore. 30 - 70% of it is added to the oil shale ore raw material before heating and retorting, and the remaining catalyst is added to the oil shale ore raw material during the retorting process, greatly saving the usage amount of the catalyst, reducing the production cost of light fuel oil, and improving production efficiency. The above patents have the defect of being difficult to bet. CN103464179B discloses a catalyst prepared by mixing divalent cobalt and manganese salts, water, and surfactant in a certain proportion. The specific operation is to spray the catalyst solution on the surface of the crushed oil shale before the retorting and cracking of oil shale, or soak the oil shale in the catalyst solution containing surfactant. After the catalyst solution penetrates into the interior of the oil shale, the oil shale is dried naturally or forcibly, and shale oil is produced according to the original oil shale retorting and cracking process. This catalyst exposes the problem of insufficient stability. CN202210914695.9 introduces a method for processing oil shale, and the catalyst involved therein contains active components, and the active components are selected from phthalocyanine and / or its derivatives, and / or porphyrin and / or its derivatives, which can significantly reduce the activation energy in the pyrolysis processing of fossil energy substances. CN201711478641.8 introduces a catalyst for improving the oil production rate of oil shale and its preparation method. The catalyst is 40% H 2 SO 4The catalyst is prepared by using treated bentonite as the carrier, a Co salt with a certain concentration as the active component, and a Ni salt with a certain concentration as the precursor. After calcination, NiO is used as the promoter, and it is prepared through impregnation and calcination. The catalyst of the present invention has problems such as poor synergistic effect among the promoter, active component and carrier, and unsatisfactory function. CN201410145243.4 discloses a catalyst for oil shale pyrolysis, its preparation method and usage method. The described catalyst is made from the following raw materials by mass percentage: molecular sieve 2% - 8%, activated clay 1% - 5%, organic cobalt salt 10% - 60%, metal sulfide 5% - 20%, glycerate 8% - 30%, paraffin 15% - 35%; the organic cobalt salt is one or several of cobalt acetate, cobalt oxalate, cobalt naphthenate and cobalt neodecanoate; the metal sulfide is molybdenum sulfide and / or nickel sulfide. Although this method can prepare an in-situ conversion catalyst for oil shale, which contains many functional components, the stability of the catalyst is lacking. CN201710082567.1 discloses a catalyst for in-situ exploitation of oil shale, which includes magnesium sulfate and water. CN202210231818.9 discloses a catalyst prepared based on the plasma method, and the catalyst includes an oil-phase catalyst and a water-phase catalyst.

[0006] In terms of the low-cost synthesis of SAPO-11, CN202110735921.2 discloses a method for green synthesis of hierarchical pore SAPO-11 molecular sieve based on natural minerals and its preparation method. First, thermally activated kaolin is dissolved in orthophosphoric acid solution, and after stirring, deionized water, supplementary aluminum source and template agent are added. After hydrothermal crystallization, the solid product is obtained by centrifugation, and then the template agent is removed by high-temperature calcination to obtain the molecular sieve. Although this patent uses the method of obtaining silicon-aluminum source by treating natural minerals with orthophosphoric acid, there are prominent problems such as insufficient dissolution of silicon source and low crystallinity of SAPO-11 molecular sieve. CN201310726735.8 describes a method for synthesizing SAPO-34 molecular sieve using kaolin. The natural mineral kaolin reacts with phosphoric acid to provide aluminum source for the synthesis of SAPO-type molecular sieve, but there are problems such as very complex steps, cumbersome operation and being not conducive to industrial implementation.

[0007] CN201710176755.7 discloses a method for synthesizing silicoaluminophosphate molecular sieve using kaolin. First, kaolin or kaolin microspheres are calcined at 700 - 1100 °C for 1 - 4 h to obtain active Al 2 O 3 and SiO 2The calcined kaolin of the components is then mixed with a phosphorus source, a templating agent, and deionized water. After stirring evenly, an aluminum source and a silicon source are added, and the mixture is aged at room temperature for 0 to 48 hours. Then, the crystallization stock solution is heated to 150 to 250 °C for hydrothermal crystallization and demolding to obtain the required molecular sieve. Although this patent uses the step of acid treatment of natural minerals, the preparation process flow is long and the filtration is difficult, which is not conducive to industrial implementation. Moreover, it does not mention how to ensure the loss of the added functional metal ions.

[0008] CN201911211370.9 discloses a metal-phosphorus-carbon hierarchical pore catalyst and a preparation method thereof. A uniform mixed system containing a carbon source, a templating agent, a phosphorus source, a metal precursor, and a solvent is carbonized at 80-200 °C for 1-12 h, and then calcined at 200-1200 °C for 5-24 h under a protective atmosphere. Finally, the templating agent is removed to obtain the metal-phosphorus-carbon hierarchical pore catalyst. This patent is essentially different from the in-situ conversion catalyst system of shale oil.

[0009] From the above-mentioned disclosed patents, it can be seen that currently, the research on the catalyst for catalytic pyrolysis of oil shale is mainly aimed at the surface retorting technology. Moreover, the deficiencies of the above technologies are that the selectivity of the catalyst for heavy fractions is low, and the nitrogen and sulfur contents in the products are high, increasing the subsequent refining and process cost pressure. In the in-situ conversion process underground, most of the time, metal ions need to be introduced to play the role of functional components. Transition metals such as copper, iron, cobalt, nickel, manganese, zinc, molybdenum, tin, calcium, magnesium and other metal elements, halides, sulfates, carbonates, organic acid salts, etc. are added during the retorting of oil shale. These metal compounds penetrate into the micropores of oil shale in the form of a solution, having the effect of reducing the cracking temperature. Currently, according to the type, it is mainly inorganic salts, metal catalysts, metal oxides, sulfides, and halide catalysts, but most of them have problems such as insufficient stability, unremarkable effects, and a large number of constituent substances of the catalyst, complex preparation operations of the catalyst, and high costs. Therefore, there is an urgent need to develop an in-situ conversion catalyst with low cost and high efficiency to reduce the activation energy required for the pyrolysis hydrocarbon generation reaction, thereby changing the reaction path and accelerating the reaction rate to reduce the temperature required for the in-situ oil and gas conversion of oil shale. Summary of the Invention

[0010] The purpose of the present invention is to provide a preparation method of a composite molecular sieve for the in-situ conversion of medium-low maturity oil shale, to solve the shortcomings of the performance and stability of the existing in-situ conversion catalysts or materials, improve the stability of the in-situ conversion catalytic materials, and lay a foundation for reducing the in-situ conversion activation energy and promoting hydrocarbon generation.

[0011] To achieve the above purpose, the present invention provides a preparation method of a composite molecular sieve for the in-situ conversion of medium-low maturity oil shale, including the following steps:

[0012] S1. Activate the industrial tailings and then add them to an acid solution, followed by aging to form mixture A;

[0013] S2. Treat the mixture of metal compounds and organic polymers with phytic acid solution to obtain mixture B;

[0014] S3. Mix mixture A, mixture B, a phosphorus source, a silicon source, a template agent, and water, stir well to obtain mixture C, place mixture C in a closed reaction kettle for crystallization, and the product is filtered and washed with water to obtain the composite molecular sieve.

[0015] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the industrial tailings are one or more of the slag after producing aluminum sulfate, fly ash, kaolin tailings, rectorite, or halloysite tailings.

[0016] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the activation conditions in step S1 are roasting at 400 - 1000 °C for 0.5 - 5 hours.

[0017] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the acid in step S1 is inorganic acid and / or organic acid. The inorganic acid is one or more of sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, and the organic acid is one or more of formic acid, citric acid, oxalic acid, acetic acid, and fruit acid.

[0018] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the concentration of the acid solution in step S1 is 0.05 - 15 mol / L, the mass ratio of the acid solution to the industrial tailings is 3 - 15, they are fully mixed at 20 - 100 °C, the pH value is controlled at 2.8 - 6.0, and the treatment time is 0.5 - 6 h.

[0019] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the organic polymer is one or several of carboxymethyl cellulose, methyl cellulose, cellulose, and starch. The metal compound is a substance containing one or more of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, silver, magnesium, calcium, and barium. The metal compound is calculated as metal ions, and the industrial tailings are calculated by the mass of Al 2 O 3 contained in it. The addition amount of the metal compound is 1 - 40% of the mass of the industrial tailings.

[0020] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the mass concentration of the phytic acid is 5 - 80%, the mass ratio of the phytic acid solution to the organic polymer is 1:1.5 - 10, and the total addition amount of the phytic acid solution and the organic polymer is 3 - 40 wt% of the mass of the industrial tailings.

[0021] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the conditions for treating the metal compound and the organic polymer with the phytic acid solution in step S2 are treatment at 50-120 °C for 0.5-6 h, preferably treatment at 60-100 °C for 1-4 h.

[0022] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the silicon source is one or more of tetraethyl orthosilicate, silica sol, white carbon black and sodium silicate; the phosphorus source is one or more of phosphoric acid, phosphorous acid, phosphates and phosphorus oxides; the template agent refers to one or more of diethylamine DEA, diisopropylamine DIPA and di-n-propylamine DPA.

[0023] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, in terms of molar ratio, in the mixture C, 0.5-3P 2 O 5 : 1.0Al 2 O 3 : 1-10Template: 0.01-2.0SiO 2 .

[0024] In the preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to the present invention, the crystallization conditions are crystallization at 140-200 °C for 20-32 h.

[0025] Advantages of the present invention:

[0026] 1: The aluminum source for synthesizing the molecular sieve is obtained by acid-treating industrial tailings, which not only fully turns waste into treasure and increases the added value of the tailings, but also provides a stable aluminum source for the synthesis of the molecular sieve.

[0027] 2: The most remarkable characteristic of phytic acid is its strong complexing effect and antioxidant property with the vast majority of metal ions. At the same time, it also has a coordination effect with organic polymers. The metal elements and polymers modified by it can form stable metal-containing chelates, enabling the functional modification components to be firmly combined with the chelates, thereby reducing the loss of metal ions.

[0028] 3: The synthesized molecular sieve contains a rich pore structure, metal functional components, and an acidic gradient distribution. It belongs to a composite catalytic material and has characteristics such as a reasonable acidic distribution and strong persistence during actual use. The key to the in-situ conversion catalyst lies in the stable and continuous effectiveness of the functional components and the gradient distribution of acidity and pores. This invention patent adopts a low-cost method. The aluminum source is obtained by acid-treating industrial tailings, and the preparation process is simple. Based on the SAPO-11 synthesis scheme, a composite catalytic material with functional components, gradient pore distribution, and acidic differences is synthesized. Moreover, the role of phytic acid chelating metal in the synthesis system enhances the stability of the metal functional components, reduces loss, releases slowly, and works continuously. The above characteristics make the temperature reduction amplitude at the maximum weight loss measured after mixing the material with oil shale decrease by 30 - 45 °C compared with not adding this material, and there is also an advantage in the temperature reduction amplitude compared with the sample of the comparative example, showing the characteristics of excellent conversion performance and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the XRD phase diagram of the molecular sieves prepared in the examples and comparative examples of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be specifically described below through examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention according to the above content of the present invention.

[0031] Source of raw materials:

[0032] 1) Natural mineral tailings: industrial products, commercially available, purchased from China Suzhou Kaolin Company

[0033] 2) Phytic acid solution: concentration 80% (mass percentage), chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0034] 3) Ferric chloride: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0035] 4) Vanadium chloride: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0036] 5) Manganese chloride: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0037] 6) Copper chloride: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0038] 7) Chromium chloride: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0039] 8) Barium chloride: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0040] 9) Magnesium chloride: chemically pure, from Sinopharm Chemical Reagent Co., Ltd.

[0041] 10) Zinc chloride: chemically pure, from Sinopharm Chemical Reagent Co., Ltd.

[0042] 11) Phosphorus source: chemically pure, from Sinopharm Chemical Reagent Co., Ltd.

[0043] 12) Phosphoric acid solution: chemically pure, from Sinopharm Chemical Reagent Co., Ltd. (mass percentage concentration: 85%)

[0044] 13) Metaphosphoric acid solution: self-prepared, mass percentage concentration 25%

[0045] 14) Silicon powder: from Qingdao Jinyang Fine Chemical Co., Ltd. (SiO 2 : 95%, mass percentage content)

[0046] 15) Carboxymethyl cellulose, analytically pure, 100 g (produced by Shanghai Reagent Co., Ltd.)

[0047] 16) Methyl cellulose, analytically pure, 100 g (produced by Shanghai Reagent Co., Ltd.)

[0048] 17) Starch, analytically pure, 100 g (produced by Shanghai Reagent Co., Ltd.)

[0049] 18) Sodium silicate: industrial grade, from the Catalyst Division of Lanzhou Petrochemical Company (SiO 2 : 19.75%, Na 2 O: 6.95%, mass percentage content)

[0050] 19) Colloidal silica: chemically pure, from Qingdao Jinyang Fine Chemical Co., Ltd. (SiO 2 : 30%, mass percentage content)

[0051] 20) Tetraethyl orthosilicate: analytically pure, 500 ml (produced by Shanghai Reagent Co., Ltd.), mass percentage content of SiO2: 30%

[0052] 21) Diethylamine (DEA): analytically pure, 500 mL, ≥98.5% (mass percentage content), from Sinopharm Chemical Reagent Co., Ltd.

[0053] 22) Diisopropylamine (DIPA): analytically pure, 250 mL, ≥98.0% (mass percentage content), from Sinopharm Chemical Reagent Co., Ltd.

[0054] 23) Di-n-propylamine (DPA): 250 mL, ≥99.0% (mass percentage content), analytically pure, from Sinopharm Chemical Reagent Co., Ltd.

[0055] Specific analysis method:

[0056] The crystallinity of SAPO-11 molecular sieve was tested on a D / max-3C X-ray powder diffractometer manufactured by Rigaku Corporation of Japan. The crystallinity of the sample was determined by X-ray diffraction method. Taking the characteristic diffraction peaks of the SAPO-11 standard sample at 2θ = 8.1°, 9.4°, 13.1°, 15.6°, 20.3°, 21.2°, 22.1°, 22.8, 23.2°, etc. as the standard, the ratio of the peak areas obtained by comparing the synthesized sample with it was used as the final crystallinity value.

[0057] BET characterization was used to determine the specific surface area and pore volume of the sample. In this patent, an ASAP 2460 full-automatic specific surface area analyzer of Micromeritics Company of the United States was used. Test method: First, the sample was pretreated at a high temperature (300 °C) in a vacuum state for 8 h; then, when the liquid nitrogen temperature was -196 °C, the sample was analyzed. The total specific surface area data measured was calculated by the BET method, while the remaining surface area and micropore volume data were calculated by the t-plot method, and the mesopore volume was calculated by the BJH method.

[0058] TG-DSC characterization was used to determine the change of the sample mass with temperature, so as to determine the thermal stability performance of the sample. The DSC curve was obtained by differentiating the TG curve. In this article, a Themys TGA synchronous thermal analyzer of Setaram Company of France was used. Test method: First, the crucible in the instrument was zeroed, then the sample (5 - 10 mg) was put in and heated to 800 °C at a rate of 20 °C.

[0059] Elemental characterization: For elemental determination, a ZSX-Primus-II X-ray fluorescence spectrometer of Rigaku Corporation of Japan was used in this article. Tube voltage: 50 KV, current: 50 mA.

[0060] Example 1:

[0061] (1) Weigh 6.81 grams of the slag after producing aluminum sulfate (Al 2 O 3 content is 30%), activate it at 1000 °C for 0.5 h, then add 272.4 grams of 15 mol / L sulfuric acid solution and mix well at 20 °C, control the pH value at 6.0, and treat it for 0.5 h to obtain mixture A1;

[0062] (2) After treating the mixture of 0.1 gram of starch and 0.63 gram of vanadium chloride with 0.15 gram of 25% mass concentration phytic acid solution at 120 °C for 0.5 h, mixture B1 was obtained. Stir the above mixture A1 and mixture B1 for 2 h to obtain a mixed gel;

[0063] (3) Mix the mixed gel with 0.1 g of tetraethyl orthosilicate, 13.8 g of phosphoric acid, and 2.93 g of diethylamine, and ensure that the gel ratio is: 1.5P 2 O 5 :1.0Al 2 O 3 :1Template:0.01SiO 2 , and then crystallize at 140 °C for 32 h, filter and wash with water to obtain the final product S1. After suction filtration and washing, S1 is dried at 120 °C for 5 h and calcined at 550 °C to remove the template agent, and then thermogravimetric tests and other characterizations are carried out.

[0064] Example 2:

[0065] (1) Weigh 72.6 g of fly ash ((Al 2 O 3 content is 44%) and activate it at 800 °C for 4 h, then add 871 g of 8 mol / L hydrochloric acid solution and mix well at 50 °C, control the pH value at 2.8, and treat for 3 h to obtain mixture A2;

[0066] (2) Treat the mixture of 2.04 g of carboxymethyl cellulose and 29.19 g of chromium chloride with 20.4 g of 5% mass concentration phytic acid solution at 120 °C for 0.5 h to obtain mixture B2, and stir the above mixture A2 and mixture B2 for 2 h to obtain a mixed gel;

[0067] (3) Mix the mixed gel with 17.54 g of silica sol, 30.8 g of phosphorous acid, and 44.37 g of diisopropylamine, and ensure that the gel ratio is: 3P 2 O 5 :1.0Al 2 O 3 :7Template:1.4SiO 2 , and then crystallize at 180 °C for 20 h, filter and wash with water to obtain the final product S2. After suction filtration and washing, S2 is dried at 120 °C for 5 h and calcined at 550 °C to remove the template agent, and then thermogravimetric tests and other characterizations are carried out.

[0068] Example 3:

[0069] (1) Weigh 46.9 g of kaolin tailings ((Al 2 O 3 content is 20%) and activate it at 600 °C for 2.7 h, then add 703 g of 0.05 mol / L nitric acid solution and age at 90 °C for 4 h, control the pH value at 3.0, and treat for 1 h to obtain mixture A3;

[0070] (2) 1.53 g of methylcellulose and 5.45 g of iron chloride were treated with 7.65 g of phytic acid solution with a mass concentration of 80% at 60 °C for 3 h to obtain mixture B3. After stirring the above mixture A3 and mixture B3 for 2 h, a mixed gel was obtained;

[0071] (3) The mixed gel was fully mixed with 3.05 g of silica white, 47.08 g of ammonium phosphate, and 20.24 g of di-n-propylamine to ensure that the gel ratio was: 2.87P 2 O 5 :1.0Al 2 O 3 :3.63Template:0.83SiO 2 , and then crystallized at 170 °C for 28 h, filtered and washed with water to obtain the final product S3. After suction filtration and washing, S3 was dried at 120 °C for 5 h and calcined at 550 °C to remove the template agent, and then thermogravimetric tests and other characterizations were carried out.

[0072] Example 4:

[0073] (1) Weigh 75 g of rectorite tailings ((Al 2 O 3 content is 20%) and activate it at 700 °C for 3 h, then add 600 g of 3 mol / L phosphoric acid solution and age it at 60 °C for 2 h, control the pH value at 3.2, and treat it for 1.5 h to obtain mixture A4;

[0074] (2) 1.22 g of cellulose and 8.93 g of magnesium chloride were treated with 9.76 g of phytic acid solution with a mass concentration of 60% at 90 °C for 4 h to obtain mixture B4. After stirring the above mixture A4 and mixture B4 for 2 h, a mixed gel was obtained;

[0075] (3) The mixed gel was fully mixed with 22.26 g of diisopropylamine, 16.09 g of diethylamine, 26.4 g of water glass, and 120.71 g of ammonium pyrophosphate to ensure that the gel ratio was: 2.5P 2 O 5 :1.0Al 2 O 3 :10Template:2SiO 2 , and then crystallized at 180 °C for 22 h, filtered and washed with water to obtain the final product S4. After suction filtration and washing, S4 was dried at 120 °C for 5 h and calcined at 550 °C to remove the template agent, and then thermogravimetric tests and other characterizations were carried out.

[0076] Example 5:

[0077] (1) Weigh 77.59 g of halloysite ((Al 2 O 3The content is 20%) was activated at 900 °C for 1 h, then 388 g of 12 mol / L formic acid solution was added and aged at 80 °C for 2.5 h, the pH value was controlled at 4.1, and treated for 2 h to obtain mixture A5;

[0078] (2) 0.82 g of starch and 1.65 g of barium chloride were treated with 2.46 g of 40% mass concentration phytic acid solution at 110 °C for 1.5 h to obtain mixture B5. The above mixture A5 and mixture B5 were stirred for 2 h to obtain a mixed gel;

[0079] (3) The mixed gel was fully mixed with 6 g of silica sol, 21.58 g of phosphorus pentoxide, 18.21 g of diisopropylamine, and 8.78 g of diethylamine to ensure that the gel ratio was: 2P 2 O 5 :1.0Al 2 O 3 :4Template:0.4SiO 2 , and then crystallized at 160 °C for 26 h, filtered and washed with water to obtain the final product S5. After S5 was filtered and washed, it was dried at 120 °C for 5 h and calcined at 550 °C to remove the template agent, and then subjected to thermogravimetric tests and other characterizations.

[0080] Example 6:

[0081] (1) Weigh 58.38 g of the slag after producing aluminum sulfate ((Al 2 O 3 The content is 20%) was activated at 500 °C for 2 h, then 583.8 g of 10 mol / L citric acid solution was added and aged at 90 °C for 1 h, the pH value was controlled at 5.2, and treated for 6 h to obtain mixture A6;

[0082] (2) 1.02 g of starch and 10.52 g of manganese chloride were treated with 2.04 g of 30% mass concentration phytic acid solution at 100 °C for 3.5 h to obtain mixture B6. The above mixture A6 and mixture B6 were stirred for 2 h to obtain a mixed gel;

[0083] (3) The mixed gel was fully mixed with 1.2 g of silica white, 115.29 g of phosphoric acid, 1.46 g of diethylamine and 3.04 g of di-n-propylamine to ensure that the gel ratio was: 1P 2 O 5 :1.0Al 2 O 3 :2.2Template:0.8SiO 2 , and then crystallized at 150 °C for 30 h, filtered and washed with water to obtain the final product S6. After S6 was filtered and washed, it was dried at 120 °C for 5 h and calcined at 550 °C to remove the template agent, and then subjected to thermogravimetric tests and other characterizations.

[0084] Example 7:

[0085] (1) Weigh 28.71 grams of fly ash ((Al 2 O 3 content is 40%) and activate it at 400 °C for 4 h. Then add 86.13 grams of 5 mol / L oxalic acid solution and age it at 70 °C for 1.5 h. Control the pH value at 5.8 and process it for 4 h to obtain mixture A7;

[0086] (2) Treat 0.31 grams of carboxymethyl cellulose and 4.36 grams of copper chloride with 2.48 grams of 70% mass concentration of phytic acid solution at 80 °C for 5 h to obtain mixture B7. Stir the above mixture A7 and mixture B7 for 2 h to obtain a mixed gel;

[0087] (3) After fully mixing the mixed gel with 11.48 grams of water glass, 13.68 grams of di-n-propylamine, 7.4 grams of 25% mass concentration of metaphosphoric acid and 18 grams of water, ensure that the gel ratio is: 0.5P 2 O 5 : 1.0Al 2 O 3 : 6Template: 1.7SiO 2 , and then crystallize it at 165 °C for 28 h. Filter and wash with water to obtain the final product S7. After suction filtration and washing, S7 is dried at 120 °C for 5 h and calcined at 550 °C to remove the template agent, and then thermogravimetric tests and other characterizations are carried out.

[0088] Example 8:

[0089] (1) Weigh 33.10 grams of kaolin tailings (Al2O3 content is 30%) and activate it at 750 °C for 3.5 h. Then add 397.2 grams of 1 mol / L fruit acid solution and age it at 75 °C for 3.5 h. Control the pH value at 4.5 and process it for 5 h to obtain mixture A8;

[0090] (2) Treat 1.73 grams of cellulose and 5.58 grams of zinc chloride with 10.38 grams of 10% mass concentration of phytic acid solution at 90 °C for 4 h to obtain mixture B8. Stir the above mixture A8 and mixture B8 for 2 h to obtain a mixed gel;

[0091] (3) After fully mixing the mixed gel with 0.78 grams of tetraethyl orthosilicate, 11.39 grams of diethylamine, 8.529 grams of 85% mass percentage of phosphoric acid solution and 23 grams of water, ensure that the gel ratio is: 1.9P 2 O 5 : 1.0Al 2 O 3 : 8Template: 0.2SiO 2Then crystallize at 180℃ for 30h, filter and wash to obtain the final product S8. After filtration and washing, S8 is dried at 120℃ for 5h and calcined at 550℃ to remove the template, and then thermogravimetric test and other characterizations are performed.

[0092] Comparative Example 1:

[0093] Compared with Example 4:

[0094] (1) treating 1.22 g of cellulose and 8.93 g of magnesium chloride with 9.76 g of a 60% mass concentration phytic acid solution at 90° C. for 4 h to obtain a mixture A9;

[0095] (2) Mixture A9 was thoroughly mixed with 6.18 g of pseudo-boehmite, 22.26 g of diisopropylamine, 16.09 g of diethylamine, 26.4 g of water glass and 120.71 g of ammonium pyrophosphate to ensure that the gel ratio was: 2.5P 2 O 5 :1.0Al 2 O 3 :10Template:2SiO 2 Then, the product was crystallized at 180°C for 22 hours, filtered and washed to obtain the final product S9. After filtration and washing, S9 was dried at 120°C for 5 hours and calcined at 550°C to remove the template, and then subjected to thermogravimetric testing and other characterizations.

[0096] Comparative Example 2:

[0097] Compared with Example 1:

[0098] (1) Weigh 68.1 g of slag from the production of aluminum sulfate ((Al 2 O 3 content of 30%), activated at 1000° C. for 0.5 h, then added with 272.4 g of 15 mol / L sulfuric acid solution and mixed thoroughly at 20° C., the pH value was controlled at 6.0, and treated for 0.5 h to obtain a mixture A10;

[0099] (2) Mix the mixture A10, 0.63 g of vanadium chloride, 0.1 g of ethyl orthosilicate, 13.8 g of phosphoric acid, and 2.93 g of diethylamine to ensure that the gel ratio is: 1.5P 2 O 5 :1.0Al 2 O 3 :1Template:0.01SiO 2 Then, the product was crystallized at 140°C for 32 hours, filtered and washed to obtain the final product S10. After filtration and washing, S10 was dried at 120°C for 5 hours and calcined at 550°C to remove the template, and then thermogravimetric testing and other characterizations were performed.

[0100] Table 1 Quality of Synthesized SAPO-11 Molecular Sieve and In-situ Conversion Effect

[0101]

[0102] Figure 1 This is the XRD pattern of the SAPO-11 molecular sieve synthesized in the examples and comparative examples of the present invention. Table 1 shows the implementation effect of this invention patent. From Figure 1 the results, it can be seen that the molecular sieve prepared according to this invention patent is a pure-phase molecular sieve without other miscellaneous crystals. The results in Table 1 show that the aluminum source for synthesizing the molecular sieve is obtained by acid treatment of different industrial tailings. While fully turning waste into treasure and increasing the added value of tailings, it can also synthesize high-quality SAPO molecular sieves. Comparing Example 4 and Comparative Example 1, since the product after acid treatment of natural mineral tailings is used as the aluminum source, the synthesized molecular sieve contains a rich pore structure and an acidic gradient distribution while synthesizing the molecular sieve, which belongs to a composite catalytic material. Therefore, the specific surface area and pore volume increase by 72 m 2 / g and 0.12 mL / g respectively. The most remarkable characteristic of phytic acid is its extremely strong complexing effect with most metal ions and antioxidant properties. At the same time, it also has a complexing effect with organic polymers. After being modified by it, the metal elements and polymers can form stable metal-containing chelates, making the functional modification components firmly combined with the chelates, thereby reducing the loss of metal ions. It can be seen from the comparison of the two that the retention rate of metal components has increased by 8.3%, and thus it has characteristics such as strong in-situ conversion persistence during actual use. The key to the in-situ conversion catalyst lies in the stable and continuous effectiveness of the functional components and the gradient distribution of acidity and pores. This invention patent adopts a low-cost method, and the aluminum source is obtained by acid treatment of industrial tailings, and the preparation process is simple.

[0103] Comparing Example 1 and Comparative Example 2, it can be seen that the addition of phytic acid plays a complexing role with the organic polymer, as well as its extremely strong complexing effect and antioxidant properties with metal ions, enhancing the stability of the metal functional components, reducing loss, slowly releasing, and continuously taking effect. The above characteristics make the temperature reduction amplitude at the maximum weight loss measured after the material is mixed with oil shale decrease by 26 °C compared with not adding this material.

[0104] Certainly, the present invention can also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations should all fall within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale, characterized in that, it comprises the following steps: S1, activating the industrial tailings and then adding an acid solution, followed by aging to form mixture A; S2, treating the mixture of metal compounds and organic polymers with a phytic acid solution to obtain mixture B; S3, mixing mixture A, mixture B, a phosphorus source, a silicon source, a template agent and water, stirring evenly to obtain mixture C, and subjecting mixture C to crystallization in a closed reaction kettle, and filtering and washing the product to obtain the composite molecular sieve.

2. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, the industrial tailings are one or more of the slag after producing aluminum sulfate, fly ash, kaolin tailings, rectorite or halloysite tailings.

3. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, the activation conditions in step S1 are roasting at 400 - 1000 °C for 0.5 - 5 hours.

4. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, the acid in step S1 is an inorganic acid and / or an organic acid, the inorganic acid is one or more of sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, and the organic acid is one or more of formic acid, citric acid, oxalic acid, acetic acid and fruit acid.

5. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, the concentration of the acid solution in step S1 is 0.05 - 15 mol / L, the mass ratio of the acid solution to the industrial tailings is 3 - 15, they are fully mixed at 20 - 100 °C, the pH value is controlled at 2.8 - 6.0, and the treatment is carried out for 0.5 - 6 h.

6. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, The organic polymer is one or more of carboxymethyl cellulose, methyl cellulose, cellulose, and starch. The metal compound is a substance containing one or more of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, silver, magnesium, calcium, and barium. The metal compound is calculated as metal ions, and the industrial tailings are calculated by the Al 2 O 3 content by mass. The addition amount of the metal compound is 1-40% of the mass of the industrial tailings.

7. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, the mass concentration of the phytic acid is 5 - 80%, the mass ratio of the phytic acid solution to the organic polymer is 1:1.5 - 10, and the total addition amount of the phytic acid solution and the organic polymer is 3 - 40 wt% of the mass of the industrial tailings.

8. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, the conditions for treating the metal compounds and the organic polymer with the phytic acid solution in step S2 are treating at 50 - 120 °C for 0.5 - 6 h, preferably treating at 60 - 100 °C for 1 - 4 h.

9. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, the silicon source is one or several of tetraethyl orthosilicate, silica sol, white carbon black and water glass; the phosphorus source is one or several of phosphoric acid, phosphorous acid, phosphates and phosphorus oxides; the template agent refers to one or several of diethylamine DEA, diisopropylamine DIPA and di-n-propylamine DPA.

10. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, In terms of molar ratio, in the mixture C, 0.5 to 3P 2 O 5 : 1.0 Al 2 O 3 : 1 to 10 Template: 0.01 to 2.0 SiO 2 .

11. The preparation method of the composite molecular sieve for in-situ conversion of medium- and low-maturity oil shale according to claim 1, characterized in that, the crystallization conditions are crystallization at 140 - 200 °C for 20 - 32 h.

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