Catalyst for reducing kerogen in-situ conversion activation energy and preparation method and application thereof

Abstract

The invention discloses a catalyst for reducing kerogen in-situ conversion activation energy and a preparation method and application thereof. The preparation method comprises the following steps: mixing natural minerals containing magnesium and / or calcium with an acid solution, reacting for a period of time, mixing with alcohol or an alcohol solution, and reacting for a period of time to obtain a composite system; mixing an alkaline earth metal compound and / or a transition metal compound with the phytic acid solution, and reacting for a period of time to obtain a system containing the phytic acid-metal ion chelate; and mixing the composite system with a system containing a phytic acid-metal ion chelate to obtain the catalyst. The catalyst is mixed with oil shale powder, a catalytic pyrolysis reaction is carried out under simulated formation conditions, and kerogen pyrolysis catalytic activation energy and temperature are effectively reduced.

Description

Technical Field

[0001] This invention relates to a catalyst for reducing the activation energy of in-situ conversion of kerogen, its preparation method and application, belonging to the field of in-situ conversion technology of oil shale. Background Technology

[0002] Oil shale is a high-ash sedimentary rock rich in solid combustible organic matter. When heated to high temperatures, it transforms into lightweight shale oil and shale gas through thermochemical reactions such as cracking, cyclization, and condensation. In-situ conversion of oil shale is a novel, efficient, and environmentally friendly technology for developing deep underground oil shale. Its principle involves placing an electric heater in a heating well to heat the oil shale reservoir via heat conduction, collecting the resulting shale oil and hydrocarbon gases. However, in-situ conversion of oil shale requires certain geological conditions and prolonged heating to temperatures above approximately 500°C to produce oil and gas products. This limits the potential of underground in-situ conversion of oil shale.

[0003] Oil shale pyrolysis catalysts can accelerate the breaking of long-chain molecular bonds in organic matter, converting solid or heavy organic matter into flowable light petroleum hydrocarbons. Catalytic technology holds promise for solving problems such as excessively high pyrolysis temperatures and prolonged heating times in oil shale, enabling in-situ underground conversion of oil shale. Currently, commonly used catalysts mainly include transition metal salt catalysts and non-transition metal salt catalysts.

[0004] Song et al. prepared the catalyst SO3H-APG using natural clay, attapulgite, and 3-mercaptopropyltrimethoxysilane (MPTMS). This catalyst reduced the pyrolysis temperature and activation energy of oil shale, increased the hydrocarbon yield during the oil shale conversion process, and reduced the content of oxygen-containing and nitrogen-containing compounds (Oil shale in-situ up grading with natural clay-based catalysts: enhancement of oil yield and quality[J]. Fuel, 2022, 314: 123076.).

[0005] Chang et al. found that the use of transition metal salts CoCl2 and NiCl2 can promote the pyrolysis and secondary cracking of oil shale, but the catalysts used are poor in reducing the pyrolysis temperature of oil shale, which prevents the application of in-situ underground conversion technology of oil shale to commercial development (Investigation of the effect of selected transition metal salts on the pyrolysis of Huadian oil shale, China [J]. Oil Shale, 2017, 34: 354.).

[0006] Sun Jinsheng et al. studied the catalytic pyrolysis behavior of chromium chloride on oil shale, showing that chromium chloride can reduce the pyrolysis temperature by about 50℃ and the activation energy by 44.4% (Catalytic pyrolysis of oil shale by chromium chloride and molecular simulation mechanism [J]. Journal of China University of Petroleum (Natural Science Edition), 2023, 47(1):74-80).

[0007] CN114522722A discloses a molecular sieve-containing catalyst for catalytic cracking of oil shale, comprising a rare earth mesoporous molecular sieve, a quaternary ammonium base, supported metal nano-alumina, ethyl cyclohexane, and a surfactant. The pore size of the rare earth mesoporous molecular sieve is 3–7 nm. This catalyst accelerates the conversion of oil source material to oil and gas and lowers the cracking conversion temperature of oil shale through the use of rare earth mesoporous molecular sieves. However, the catalyst has too many components, its preparation process is complex, and the compatibility of the components is poor, which limits its practical application.

[0008] CN114477317A discloses a needle-like nano-iron-based bimetallic hydroxide, in which the metal cations in the layers are composed of Fe 3+ and from Ni 2+ Mn 2+ With Co 2+ It is composed of a divalent metal cation selected from the middle, and its interlayer anion is composed of OH. - CO3 2- and OCN - Composition. This needle-shaped nano-iron-based bimetallic hydroxide possesses abundant active sites, high-temperature resistance, and structural stability. When used to catalyze the pyrolysis of oil shale, it can lower the pyrolysis temperature and achieve controllable distribution of oil shale pyrolysis products, converting them into low- and medium-carbon hydrocarbon organic matter. However, although this needle-shaped nano-iron-based bimetallic hydroxide can reduce the pyrolysis temperature and activation energy during the conversion of oil shale kerogen, it is prepared by interprecipitation, which leads to problems such as poor catalyst stability and easy loss of metal ions.

[0009] CN115703076A discloses a catalyst for use in processing fossil fuel materials. The catalyst contains an active component selected from phthalocyanines and / or their derivatives, and / or porphyrins and / or their derivatives. This catalyst can lower the activation energy in the pyrolysis processing of fossil fuel materials. However, this catalyst contains various organic substances, and the introduction of these organic substances into the formation will cause contamination.

[0010] CN107178350A discloses a method for in-situ extraction of hydrocarbons from oil shale. The method includes: adding a transition metal catalyst to a supercritical fluid; injecting the supercritical fluid containing the transition metal catalyst into a heated well; controlling the temperature and pressure of the injected supercritical fluid to create a supercritical environment within the oil shale reservoir; heating the oil shale reservoir using the supercritical fluid, and, under the action of the transition metal catalyst, causing kerogen to decompose into a mixture. The transition metal catalyst is selected from at least one of cobalt and chromium compounds. However, this method is complex and detrimental to formation environmental protection. More importantly, the transition metal catalyst used in this method is not ideal in lowering the pyrolysis temperature, and the catalyst stability is poor.

[0011] Currently, the development of catalysts to reduce the activation energy and pyrolysis temperature of in-situ kerogen conversion mainly focuses on the use of metal salts and organic materials. However, this approach suffers from several problems, including the unsatisfactory sustained effectiveness of metal ions, the environmentally unfriendly effects of organic materials on the formation, and the complexity of catalyst preparation processes.

[0012] Therefore, developing a novel catalyst to reduce the activation energy of in-situ conversion of kerogen remains one of the urgent problems to be solved in this field. Summary of the Invention

[0013] To address the aforementioned technical problems, the present invention aims to provide a catalyst for reducing the activation energy of in-situ kerogen conversion, its preparation method, and its application. When used in the pyrolysis of oil shale, the catalyst of the present invention can reduce the activation energy of in-situ kerogen conversion and the pyrolysis temperature.

[0014] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a catalyst that reduces the activation energy of in-situ conversion of kerogen, comprising the following steps:

[0015] (1) A natural mineral containing magnesium and / or calcium is mixed with an acid solution and reacted for a period of time to obtain an acid-treated natural mineral system, wherein the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0016] (2) The acid-treated natural mineral system obtained in step (1) is mixed with alcohol or alcohol solution and reacted for a period of time to obtain a composite system;

[0017] (3) Mix alkaline earth metal compounds and / or transition metal compounds with phytic acid solution and react for a period of time to obtain a system containing phytic acid-metal ion chelates;

[0018] (4) The composite system obtained in step (2) is mixed with the system containing phytic acid-metal ion chelate obtained in step (3) to obtain the catalyst that reduces the activation energy of in-situ conversion of kerogen.

[0019] In the above preparation method, preferably, in step (1), the natural mineral containing magnesium and / or calcium includes one or a combination of several of magnesite, calcite, dolomite, and montmorillonite. More preferably, the natural mineral containing magnesium and / or calcium is a natural mineral containing both magnesium and calcium.

[0020] In the above preparation method, preferably, in step (1), the acid solution includes an inorganic acid solution and / or an organic acid solution. The inorganic acid solution includes one or a combination of several of sulfuric acid solution, hydrochloric acid solution, nitric acid solution and phosphoric acid solution. The organic acid solution includes one or a combination of several of formic acid solution, citric acid solution, oxalic acid solution and acetic acid solution. The concentration of the acid solution is 0.1 to 20 mol / L.

[0021] In the above preparation method, preferably, in step (1), the mass ratio of the natural mineral containing magnesium and / or calcium to the acid solution is 1:2 to 20.

[0022] In the above preparation method, preferably, in step (1), the reaction temperature of the natural mineral containing magnesium and / or calcium with the acid solution is 20 to 100°C, and the reaction time is 10 to 60 minutes.

[0023] In the above preparation method, preferably, in step (1), the total mass of magnesium and / or calcium (based on the mass of the elements) in the liquid phase of the acid-treated natural mineral system accounts for 20-95% of the total mass of the metals in the natural mineral containing magnesium and / or calcium. It should be noted that when both magnesium and calcium are present, the total mass of magnesium and calcium is used.

[0024] In the above preparation method, preferably, in step (2), the mixing ratio of the acid-treated natural mineral system and the alcohol or alcohol solution is: the ratio of the mass of magnesium and / or calcium in the liquid phase of the acid-treated natural mineral system (when both magnesium and calcium are present, the total mass of magnesium and calcium) to the mass of the alcohol or alcohol solution (when an alcohol solution is used, the mass of the solution) is 8-2:2-8.

[0025] In the above preparation method, preferably, in step (2), the alcohol includes one or a combination of methanol, ethanol and propanol, the alcohol solution includes one or a combination of methanol aqueous solution, ethanol aqueous solution and propanol aqueous solution, and the mass concentration of the alcohol solution is 10-90%.

[0026] In the above preparation method, preferably, in step (2), the reaction temperature of the acid-treated natural mineral system with the alcohol or alcohol solution is 20-60°C, and the reaction time is 10-60 minutes.

[0027] In the above preparation method, preferably, in step (3), the alkaline earth metal compound and / or transition metal compound includes one or more salt compounds of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, silver, magnesium, calcium and barium.

[0028] In the above preparation method, preferably, in step (3), the mass concentration of the phytic acid solution is 5-80%.

[0029] In the above preparation method, preferably, in step (3), the mass ratio of the alkaline earth metal compound and / or transition metal compound to the phytic acid solution is 1:1 to 10.

[0030] In the above preparation method, preferably, in step (3), the reaction temperature of the alkaline earth metal compound and / or transition metal compound with the phytic acid solution is 30-100°C, more preferably 50-80°C, and the reaction time is 0.5-6 hours, more preferably 1-4 hours.

[0031] In the above preparation method, preferably, in step (4), the mixing mass ratio of the composite system to the system containing phytic acid-metal ion chelate is 9-1:1-9.

[0032] The second aspect of the present invention provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, which is prepared by the above-described method for preparing a catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0033] The third aspect of the present invention provides the application of the above-mentioned catalyst for reducing the activation energy of in-situ kerogen conversion in the pyrolysis reaction of oil shale, wherein the application is carried out in the following manner: the catalyst for reducing the activation energy of in-situ kerogen conversion is brought into contact with oil shale and subjected to a pyrolysis reaction to reduce the activation energy of in-situ kerogen conversion of oil shale and obtain pyrolysis products.

[0034] In the above applications, preferably, the amount of the catalyst used to reduce the activation energy of in-situ conversion of kerogen is 10-90% of the total mass of the oil shale.

[0035] The technical solution of the present invention has at least the following beneficial effects:

[0036] 1. This invention treats natural minerals containing magnesium and / or calcium with an acid solution, which not only increases the specific surface area and pore volume of the natural minerals, but more importantly, the acid treatment yields free metal ions, laying the foundation for the subsequent combination of magnesium and / or calcium ions with alcohols to form crystalline alcoholic compounds. Simultaneously, the solid phase in the acid-treated natural mineral system can serve as a porous "reaction bed" with a high specific surface area, effectively adsorbing and accommodating alcohols, and continuously providing metal ions for further combination with alcohols, thus exerting a slow-release effect with strong stability. Furthermore, when used for catalytic pyrolysis of oil shale, it also facilitates the mass transfer and diffusion of hydrocarbons obtained after in-situ conversion of oil shale.

[0037] 2. In this invention, an acid-treated natural mineral system is mixed and reacted with an alcohol or an alcohol solution. Because magnesium and / or calcium ions in the liquid phase of the system have empty orbitals, while the alcohol has lone pairs of electrons from oxygen, magnesium and / or calcium ions react with the alcohol to form stable crystalline alcoholic compounds. The alcoholic compounds and the acid-treated natural mineral system form a complex system, laying the foundation for subsequent structural transformations to form magnesium and / or calcium complexes with alcohols.

[0038] 3. Under in-situ transformation conditions in oil shale formations, the alcohols in this composite system of the present invention will slowly undergo chemical reactions to form complexes of magnesium and / or calcium with alcohols, while continuously releasing water molecules. The released water molecules are in a supercritical state under in-situ transformation conditions in oil shale formations, which can efficiently dissolve hydrocarbons and salts in the rock strata and enter the kerogen network structure voids in the oil shale, promoting the discharge of generated oil and gas, thereby achieving the effect of enhancing energy and displacing oil.

[0039] 4. This invention utilizes phytic acid solution to complex alkaline earth metal ions and / or transition metal ions, obtaining a system containing phytic acid-metal ion chelates. Phytic acid exhibits extremely strong complexing effects with most metal ions and possesses strong antioxidant properties. Alkaline earth metal compounds and / or transition metal compounds treated with phytic acid solution can form stable phytic acid-metal ion chelates. The alkaline earth metal ions and / or transition metal ions introduced into oil shale through the above two pathways possess significant Lewis acid characteristics, fully leveraging the catalytic effect of the metals to promote the cracking of long-chain aliphatic hydrocarbons into short-chain aliphatic hydrocarbons, exerting a catalytic cracking effect. This catalytic action rapidly converts kerogen into short-chain mobile hydrocarbons. Under this catalytic mechanism, alkaline earth metal ions and / or transition metal ions work together with water molecules released from alcohols in the composite system, thereby lowering the pyrolysis temperature and reducing the activation energy for in-situ conversion of kerogen.

[0040] Therefore, the catalyst of this invention avoids the traditional approach of adding functional components to enhance oil recovery. Instead, it adopts a slow-release technology. When pyrolyzing oil shale, the catalyst can significantly reduce the activation energy and pyrolysis temperature of in-situ conversion of kerogen. Furthermore, the catalyst has a high metal retention rate, good sustained metal ion activity, strong stability, and good environmental performance. Attached Figure Description

[0041] Figure 1 This is an electron microscope image of the montmorillonite used in Example 4.

[0042] Figure 2 The image shows an electron microscope (EM) image of the solid phase of the acid-treated natural mineral system obtained in step (1) of Example 4. Detailed Implementation

[0043] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0044] Unless otherwise specified, the experimental steps or conditions in the following examples and comparative examples shall be performed in accordance with the conventional experimental procedures or conditions described in existing technical literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0045] The sources of raw materials or equipment used in the following examples and comparative examples are as follows:

[0046] Magnesite (Mg: 42.02%, Ca: 7.18%), calcite (Mg: 30%, Ca: 50%), dolomite (Mg: 25.32%, Ca: 21.72%), and montmorillonite (Mg: 22%, Ca: 34%): Shandong Xinhai Mining Technology Equipment Co., Ltd. It should be noted that the Mg and Ca contents in these natural minerals are calculated as the mass content of elemental Mg and Ca.

[0047] Sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, citric acid, oxalic acid, and acetic acid: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0048] Methanol, ethanol, and propanol: Sinopharm Chemical Reagent Co., Ltd., analytical grade.

[0049] Phytic acid: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0050] Vanadium chloride, chromium chloride, manganese chloride, ferric chloride, cobalt chloride, nickel chloride, copper chloride, zinc chloride, yttrium chloride, zirconium chloride, silver chloride, magnesium chloride, calcium chloride, and barium chloride: chemically pure, Sinopharm Chemical Reagent Co., Ltd.

[0051] Oil shale: 80-120 mesh, Changqing Oilfield Branch of China National Petroleum Corporation.

[0052] The content of metallic elements, such as magnesium and calcium, in the minerals in the following examples and comparative examples was determined by EDTA titration.

[0053] The surface morphology of the samples was measured using an Ultra Plus scanning electron microscope from Carl Zeiss GmbH, Germany. Operating parameters: accelerating voltage 5–20 kV, working distance: WD = 8–12 mm, magnification: 86–200 kx. Specific operating procedures included: first, subjecting the sample to two gold sputtering treatments for 10 minutes each, then placing the sample on the observation platform for observation.

[0054] The following examples and comparative examples include methods for evaluating the performance of catalysts:

[0055] The pyrolysis catalytic performance of the catalyst was evaluated using a Rock-eval 6 rock pyrolysis system manufactured by VINCI, France. The pyrolysis reaction was performed according to the standard GB / T18602-2012. The test procedure included: heating the mixture of catalyst and oil shale sample to 300℃ at a heating rate of 10℃ / min and holding at that temperature for 3 minutes, analyzing S1 using gas chromatography; then, programming the temperature within the range of 300℃ to 800℃ at a heating rate of 10℃ / min and analyzing S2 using gas chromatography. S1 refers to the free hydrocarbon content (mg / g) produced by the pyrolysis of a unit mass of oil shale sample below 300℃, and S2 refers to the hydrocarbon content (mg / g) produced by the pyrolysis of a unit mass of oil shale sample between 300℃ and 800℃. The pyrolysis temperature was obtained by the temperature corresponding to the highest point of the S2 peak in the gas chromatogram. The activation energy was calculated using the classic Arrhenius equation.

[0056] The thermal decomposition of a substance is described by equation (4.1):

[0057]

[0058] Where f(α) is a function whose type depends on the reaction mechanism;

[0059] α represents the degree of transformation, which is the normalized form of the weight loss data of oil shale samples, and can be defined by formula (4.2).

[0060]

[0061] Where m is the initial mass of the sample, mg; mf is the final mass of the sample, mg; and mi is the mass of the sample at temperature Ti, mg.

[0062] k is a temperature-dependent reaction rate constant, usually defined by the Arrhenius equation:

[0063]

[0064] Where A is the pre-exponential factor of the decomposition reaction, min- 1 E is the activation energy of the pyrolysis reaction, kJ / mol; R is the universal gas constant, 8.134 J·mol⁻¹. 1 ·K- 1 T is the thermodynamic temperature, K;

[0065] Substituting formula (4.3) into formula (4.1), we get:

[0066]

[0067] Based on the uniform kinetics of the reaction, f(α) can be defined as:

[0068] f(α)=(1-α) (4 0.5 ) , where n is the order of the reaction;

[0069] Substituting equation (4.5) into equation (4.4), the expression for the reaction rate is:

[0070]

[0071] For non-isothermal measurements using a linear heating rate program, equation (4.4) can be rewritten in its final form:

[0072]

[0073] Finally, a graph is plotted, and the values ​​of activation energy E and pre-exponential factor A can be obtained from the slope and intercept of the linear fitting line, respectively.

[0074] Example 1

[0075] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0076] (1) 50 g of magnesite and a 0.1 mol / L sulfuric acid solution were mixed at a mass ratio of 1:2 at 20 °C and reacted at 20 °C for 60 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0077] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 60% of the metal mass in magnesite.

[0078] (2) 3.69 g of a 10% methanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 20°C with stirring for 60 minutes to obtain a composite system;

[0079] (3) Mix 0.09 g of vanadium chloride with 0.09 g of phytic acid solution with a mass concentration of 5% at 30°C and react for 6 hours to obtain a system containing phytic acid-metal ion chelate;

[0080] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 9:1 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0081] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 0.3 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the kerogen pyrolysis temperature was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0082] It should be noted that the composite system obtained in step (2) of the catalyst preparation method in each embodiment of the present invention includes a solid phase and a liquid phase. Before mixing with the system containing phytic acid-metal ion chelate obtained in step (3), the composite system needs to be dispersed evenly. Similarly, the catalyst in each embodiment of the present invention includes a solid phase and a liquid phase. Before mixing with the oil shale sample, the catalyst needs to be dispersed evenly. This ensures that the ratio of solid phase to liquid phase in the system is uniform when weighed.

[0083] Example 2

[0084] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0085] (1) 20 grams of calcite and a 2.5 mol / L hydrochloric acid solution were mixed at a mass ratio of 1:18 at 50°C and reacted at 50°C for 40 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0086] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 30% of the metal mass in calcite.

[0087] (2) 2.06 g of ethanol was slowly added to the acid-treated natural mineral system and reacted at 60 °C with stirring for 10 minutes to obtain a composite system;

[0088] (3) 2.74 g of chromium chloride and 27.41 g of phytic acid solution with a mass concentration of 56% were mixed at 100 °C and reacted for 0.5 hours to obtain a system containing phytic acid-metal ion chelate;

[0089] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 8:2 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0090] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 2.7 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the pyrolysis temperature of kerogen was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0091] Example 3

[0092] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0093] (1) 70 g of dolomite and a 20 mol / L formic acid solution were mixed at a mass ratio of 1:20 at 30 °C and reacted at 30 °C for 20 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0094] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 80% of the metal mass in the dolomite.

[0095] (2) 17.56 g of 20% ethanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 30°C with stirring for 20 minutes to obtain a composite system.

[0096] (3) 1.77 g of manganese chloride and 8.84 g of phytic acid solution with a mass concentration of 72% were mixed at 60°C and reacted for 1 hour to obtain a system containing phytic acid-metal ion chelate;

[0097] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 7:3 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0098] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 2.4 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the pyrolysis temperature of kerogen was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0099] Example 4

[0100] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0101] (1) 60 g of montmorillonite and a 15 mol / L formic acid solution were mixed at a mass ratio of 1:5 at 70 °C and reacted at 70 °C for 30 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0102] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 90% of the metal mass in montmorillonite.

[0103] Electron micrographs of natural minerals before and after acid treatment are shown below. Figure 1 and Figure 2 As shown, the acid-treated natural minerals (i.e., the solid phase) contain a lot of pores, with abundant specific surface area and pore volume. They can fully adsorb and accommodate alcohols, and continuously provide metal ions to combine with alcohols, thus playing a slow-release role and having strong stability.

[0104] (2) 30.24 g of a 30% (w / w) propanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 50°C with stirring for 30 minutes to obtain a composite system;

[0105] (3) Mix 0.87 g of ferric chloride with 6.08 g of phytic acid solution with a mass concentration of 80% at 50°C and react for 2 hours to obtain a system containing phytic acid-metal ion chelate;

[0106] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 6:4 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0107] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 2.1 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the kerogen pyrolysis temperature was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0108] Example 5

[0109] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0110] (1) 80 g of montmorillonite and a 7 mol / L citric acid solution were mixed at a mass ratio of 1:7 at 40 °C and reacted at 40 °C for 45 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0111] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 20% of the metal mass in montmorillonite.

[0112] (2) 11.81 g of a 45% methanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 55°C with stirring for 35 minutes to obtain a composite system.

[0113] (3) 1.85 g of cobalt chloride and 5.54 g of phytic acid solution with a mass concentration of 63% were mixed at 40°C and reacted for 3 hours to obtain a system containing phytic acid-metal ion chelates;

[0114] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 5:5 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0115] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 1.8 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the kerogen pyrolysis temperature was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0116] Example 6

[0117] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0118] (1) 100g of dolomite and a 9mol / L citric acid solution were mixed at a mass ratio of 1:9 at 80℃ and reacted at 80℃ for 50 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0119] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 95% of the metal mass in the dolomite.

[0120] (2) 104.27 g of 55% ethanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 35°C with stirring for 25 minutes to obtain a composite system.

[0121] (3) 1.66 g of nickel chloride and 13.25 g of phytic acid solution with a mass concentration of 47% were mixed at 90 °C and reacted for 3.5 hours to obtain a system containing phytic acid-metal ion chelate;

[0122] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 4:6 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0123] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 1.5 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the pyrolysis temperature of kerogen was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0124] Example 7

[0125] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0126] (1) 70 g of magnesite and a 13 mol / L phosphoric acid solution were mixed at a mass ratio of 1:11 at 100 °C and reacted at 100 °C for 10 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0127] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 40% of the metal mass in magnesite.

[0128] (2) 55.10 g of 65% ethanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 25°C with stirring for 45 minutes to obtain a composite system.

[0129] (3) Mix 0.4 g of a mixture of copper chloride and yttrium chloride (mass ratio of copper chloride to yttrium chloride 1:1) with 0.8 g of phytic acid solution with a mass concentration of 32% at 70°C and react for 5 hours to obtain a system containing phytic acid-metal ion chelates.

[0130] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 3:7 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0131] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 0.6 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the pyrolysis temperature of kerogen was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0132] Example 8

[0133] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0134] (1) 65 g of calcite and 17 mol / L oxalic acid solution were mixed at a mass ratio of 1:13 at 30 °C and reacted at 30 °C for 55 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0135] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 50% of the metal mass in calcite.

[0136] (2) 26 g of a 70% methanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 30°C with stirring for 40 minutes to obtain a composite system.

[0137] (3) Mix 0.19 g of a mixture of zinc chloride and barium chloride (the mass ratio of zinc chloride and barium chloride is 1:1) with 1.33 g of phytic acid solution with a mass concentration of 22% at 80°C and react for 4 hours to obtain a system containing phytic acid-metal ion chelates.

[0138] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 2:8 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0139] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 0.9 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the kerogen pyrolysis temperature was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0140] Example 9

[0141] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0142] (1) 40 g of dolomite and acetic acid solution with a concentration of 4 mol / L were mixed at a mass ratio of 1:15 at 60°C and reacted at 60°C for 15 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0143] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 60% of the metal mass in the dolomite.

[0144] (2) 3.76 g of 80% propanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 20°C with stirring for 50 minutes to obtain a composite system;

[0145] (3) Mix 0.14 g of a mixture of zirconium chloride and silver chloride (the mass ratio of zirconium chloride and silver chloride is 1:1) with 0.56 g of phytic acid solution with a mass concentration of 13% at 55°C and react for 1.5 hours to obtain a system containing phytic acid-metal ion chelate.

[0146] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 1:9 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0147] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 1.2 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the pyrolysis temperature of kerogen was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0148] Example 10

[0149] This embodiment provides a catalyst for reducing the activation energy of in-situ conversion of kerogen, and its preparation method includes the following steps:

[0150] (1) 90 g of montmorillonite and a 12 mol / L sulfuric acid solution were mixed at a mass ratio of 1:19 at 75 °C and reacted at 75 °C for 25 minutes to obtain an acid-treated natural mineral system; the acid-treated natural mineral system includes a solid phase and a liquid phase.

[0151] The total mass of magnesium and calcium (by elemental mass) in the liquid phase of the acid-treated natural mineral system accounts for 70% of the metal mass in montmorillonite.

[0152] (2) 18.99 g of a 90% methanol aqueous solution was slowly added to the acid-treated natural mineral system and reacted at 45°C with stirring for 15 minutes to obtain a composite system.

[0153] (3) Mix 0.04 g of magnesium chloride and calcium chloride (mass ratio of magnesium chloride to calcium chloride is 1:1) with 0.08 g of phytic acid solution with a mass concentration of 8% at 45°C and react for 5.5 hours to obtain a system containing phytic acid-metal ion chelate.

[0154] (4) The composite system obtained in step (2) and the system containing phytic acid-metal ion chelate obtained in step (3) are mixed at a mass ratio of 5.5:4.5 to obtain the catalyst for reducing the activation energy of in-situ conversion of kerogen.

[0155] The performance of the catalyst was evaluated using a rock pyrolysis apparatus: 0.45 g of catalyst was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in the rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the pyrolysis temperature of kerogen was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0156] Comparative Example 1

[0157] No catalyst was added in this comparative example. 0.8 g of oil shale sample (80-120 mesh) was weighed and placed in a rock pyrolysis apparatus for pyrolysis reaction. The specific heating process was as described above. The pyrolysis products were analyzed by gas chromatography, and the kerogen pyrolysis temperature was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0158] Comparative Example 2

[0159] This comparative example is compared with Example 5, and only cobalt chloride is used as a catalyst. 1.85 g of cobalt chloride was thoroughly mixed with 3 g of oil shale sample (80-120 mesh), and 0.8 g of the mixture was weighed and placed in a rock pyrolysis apparatus for pyrolysis. The specific heating process is as described above. The pyrolysis products were analyzed using gas chromatography, and the kerogen pyrolysis temperature was obtained based on the analysis results. The activation energy was calculated using the Arrhenius equation, and the results are shown in Table 1.

[0160] Comparative Example 3

[0161] This comparative example is compared with Example 10, and only a 90% methanol-water solution was used as the catalyst. 18.99 g of the 90% methanol-water solution was thoroughly mixed with 3 g of oil shale sample (80-120 mesh). 0.8 g of the mixture was then weighed and placed in a rock pyrolysis apparatus for pyrolysis. The specific heating process was as described above. The pyrolysis products were analyzed using gas chromatography, and the kerogen pyrolysis temperature was obtained based on the analysis results. The activation energy was calculated using the Arrhenius equation, and the results are shown in Table 1.

[0162] Comparative Example 4

[0163] This comparative example is compared with Example 3. This comparative example only uses the solid phase in the acid-treated natural mineral system prepared in step (1) of Example 3 as a catalyst. After 2.4 g of catalyst and 3 g of oil shale sample (80-120 mesh) were thoroughly mixed, 0.8 g of the mixture was weighed and placed in a rock pyrolysis apparatus for pyrolysis reaction. The specific heating process is as described above. The pyrolysis products were analyzed by gas chromatography, and the kerogen pyrolysis temperature was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius formula. The results are shown in Table 1.

[0164] Comparative Example 5

[0165] This comparative example is compared with Example 3. This comparative example only uses the composite system prepared in step (2) of Example 3 as the catalyst. After 2.4 g of the composite system and 3 g of oil shale sample (80-120 mesh) were thoroughly mixed, 0.8 g of the mixture was weighed and placed in a rock pyrolysis apparatus for pyrolysis reaction. The specific heating process is as described above. The pyrolysis products were analyzed by gas chromatography, and the pyrolysis temperature of kerogen was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius formula. The results are shown in Table 1.

[0166] Comparative Example 6

[0167] This comparative example is compared with Example 3. This comparative example only uses the system containing phytic acid-metal ion chelate prepared in step (3) of Example 3 as the catalyst. 2.4 g of the system containing phytic acid-metal ion chelate was thoroughly mixed with 3 g of oil shale sample (80-120 mesh). 0.8 g of the mixture was weighed and placed in a rock pyrolysis apparatus for pyrolysis. The specific heating process is as described above. The pyrolysis products were analyzed by gas chromatography. The pyrolysis temperature of kerogen was obtained based on the analysis results. The activation energy was calculated according to the Arrhenius equation. The results are shown in Table 1.

[0168] Table 1. Catalyst performance evaluation results of Examples 1-10 and Comparative Examples 1-6

[0169]

[0170] As shown in Table 1, compared with Comparative Example 1 (without catalyst), Examples 1-10 of the present invention reduced the pyrolysis temperature by 4.3-12.5% ​​and the activation energy by 23.25-38.66%. Comparative Example 2 used a directly added transition metal compound as a catalyst without phytic acid chelation treatment; compared with Examples 1-10, the pyrolysis temperature and activation energy of Comparative Example 2 were not reduced. Comparative Example 3 used an alcohol as a catalyst; the pyrolysis temperature and activation energy of Comparative Example 3 were not reduced compared to Comparative Example 1. Comparative Example 4 used the solid phase of an acid-treated natural mineral system as a catalyst; the acid-treated natural minerals also did not reduce the pyrolysis temperature and activation energy. Comparative Example 5 used a composite system of alcohol and acid-treated natural minerals as a catalyst; the effect of reducing the pyrolysis temperature and activation energy was not significant. Comparative Example 6 used a system containing phytic acid-metal ion chelates as a catalyst; the pyrolysis temperature was reduced by 3°C, but the reduction in activation energy was not significant.

[0171] In summary, the catalyst of this invention combines an alcohol complex and an acid-treated natural mineral composite system with a system containing phytic acid-metal ion chelates. The crystalline alcohol slowly undergoes a chemical reaction under formation conditions, forming magnesium and / or calcium complexes with alcohols, while continuously releasing water molecules. These released water molecules are in a supercritical state, efficiently dissolving hydrocarbons and salts in the rock formation, achieving an enhanced oil displacement effect. Furthermore, the alkaline earth metal ions and / or transition metal ions introduced into the oil shale through the above two pathways possess significant Lewis acid characteristics, fully leveraging the catalytic effect of the metals to promote the cracking of long-chain aliphatic hydrocarbons into short-chain aliphatic hydrocarbons, thus rapidly converting kerogen into short-chain mobile hydrocarbons. Under this catalytic mechanism, the alkaline earth metal ions and / or transition metal ions work together with the water molecules released from the alcohol complex in the composite system, thereby reducing the pyrolysis temperature and the activation energy for in-situ conversion of kerogen. Therefore, the catalyst of this invention enhances the catalytic pyrolysis reaction effect, significantly reduces the activation energy and pyrolysis temperature for in-situ conversion of kerogen, and has excellent application prospects.

Claims

1. A method for preparing a catalyst that reduces the activation energy of in-situ conversion of kerogen, characterized in that, Includes the following steps: (1) A natural mineral containing magnesium and / or calcium is mixed with an acid solution and reacted for a period of time to obtain an acid-treated natural mineral system, wherein the acid-treated natural mineral system includes a solid phase and a liquid phase. (2) The acid-treated natural mineral system obtained in step (1) is mixed with alcohol or alcohol solution and reacted for a period of time to obtain a composite system; (3) Mix alkaline earth metal compounds and / or transition metal compounds with phytic acid solution and react for a period of time to obtain a system containing phytic acid-metal ion chelates; (4) The composite system obtained in step (2) is mixed with the system containing phytic acid-metal ion chelate obtained in step (3) to obtain the catalyst that reduces the activation energy of in-situ conversion of kerogen.

2. The preparation method according to claim 1, characterized in that, In step (1), the natural mineral containing magnesium and / or calcium includes one or a combination of several of magnesite, calcite, dolomite and montmorillonite.

3. The preparation method according to claim 1, characterized in that, In step (1), the acid solution includes an inorganic acid solution and / or an organic acid solution. The inorganic acid solution includes one or more of sulfuric acid solution, hydrochloric acid solution, nitric acid solution and phosphoric acid solution. The organic acid solution includes one or more of formic acid solution, citric acid solution, oxalic acid solution and acetic acid solution. The concentration of the acid solution is 0.1 to 20 mol / L.

4. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of the natural mineral containing magnesium and / or calcium to the acid solution is 1:2 to 20.

5. The preparation method according to claim 1, characterized in that, In step (1), the reaction temperature of the natural mineral containing magnesium and / or calcium with the acid solution is 20 to 100°C, and the reaction time is 10 to 60 minutes.

6. The preparation method according to claim 1, characterized in that, In step (1), the total mass of magnesium and / or calcium in the liquid phase of the acid-treated natural mineral system accounts for 20 to 95% of the total mass of metals in the natural mineral containing magnesium and / or calcium.

7. The preparation method according to claim 1, characterized in that, In step (2), the mixing ratio of the acid-treated natural mineral system to the alcohol or alcohol solution is: the mass ratio of magnesium and / or calcium in the liquid phase of the acid-treated natural mineral system to the mass ratio of the alcohol or alcohol solution is 8-2:2-8.

8. The preparation method according to claim 1, characterized in that, In step (2), the alcohol includes one or a combination of methanol, ethanol and propanol, and the alcohol solution includes one or a combination of methanol aqueous solution, ethanol aqueous solution and propanol aqueous solution, and the mass concentration of the alcohol solution is 10-90%.

9. The preparation method according to claim 1, characterized in that, In step (2), the reaction temperature of the acid-treated natural mineral system with the alcohol or alcohol solution is 20-60°C, and the reaction time is 10-60 minutes.

10. The preparation method according to claim 1, characterized in that, In step (3), the alkaline earth metal compound and / or transition metal compound includes one or more salts of vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, silver, magnesium, calcium and barium.

11. The preparation method according to claim 1, characterized in that, In step (3), the mass concentration of the phytic acid solution is 5-80%.

12. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of the alkaline earth metal compound and / or transition metal compound to the phytic acid solution is 1:1 to 10.

13. The preparation method according to claim 1, characterized in that, In step (3), the reaction temperature of the alkaline earth metal compound and / or transition metal compound with the phytic acid solution is 30 to 100°C, and the reaction time is 0.5 to 6 hours.

14. The preparation method according to claim 1, characterized in that, In step (4), the mass ratio of the composite system to the system containing phytic acid-metal ion chelate is 9-1:1-9.

15. A catalyst for reducing the activation energy of in-situ conversion of kerogen, characterized in that, It is prepared by the method for preparing the catalyst for reducing the activation energy of in-situ conversion of kerogen as described in any one of claims 1-14.

16. The application of the catalyst for reducing the activation energy of in-situ conversion of kerogen as described in claim 15 in the pyrolysis reaction of oil shale, characterized in that, The application is carried out in the following manner: the catalyst for reducing the activation energy of in-situ kerogen conversion is brought into contact with oil shale and subjected to pyrolysis reaction to reduce the activation energy of in-situ kerogen conversion of oil shale and obtain pyrolysis products.

17. The application according to claim 16, characterized in that, The amount of the catalyst used to reduce the activation energy of in-situ conversion of kerogen is 10-90% of the total mass of the oil shale.

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