Metal-based solid acid catalysts and their applications, methods of catalyzing pyrolysis of fossil or biomass

Abstract

The present application relates to the technical fields of fossil energy, mining, biomass, etc., and particularly relates to a metal-based solid acid catalyst and application thereof, a method for catalytic pyrolysis of fossil energy or biomass, and a method for two-stage catalytic pyrolysis of fossil energy or biomass (especially oil shale). The metal-based solid acid catalyst comprises an active component, and the active component comprises titanium; the general formula of the metal-based solid acid catalyst is TiOSO4.xH2O, wherein x is greater than or equal to 0. The catalyst is used for catalytic pyrolysis of fossil energy or biomass, which can obviously reduce the activation energy of the pyrolysis of the fossil energy or biomass, and can also reduce the content of heteroatomic compounds, increase the content of hydrocarbons, and increase the content of valuable platform chemicals in the obtained pyrolysis products through the selectivity of the catalyst.

Description

Technical Field

[0001] This invention relates to the fields of fossil energy, mining, and biomass, specifically to a metal-based solid acid catalyst and its application in processing fossil energy or biomass, a method for catalytic pyrolysis of fossil energy or biomass, and a method for two-stage catalytic pyrolysis of fossil energy or biomass (especially oil shale). Background Technology

[0002] With the rapid growth of the world's population, the rapid development of industrialization, urbanization, and modernization has led to the increasing depletion of conventional fossil fuels. The resulting energy crisis has become a major bottleneck restricting the sustainable and healthy development of the economy and society. Although the research and utilization of new green and renewable energy sources can alleviate people's dependence on these traditional fossil fuels to some extent, fossil fuels still account for about 80% of the world's energy supply. Moreover, considering the inherent low cost and availability of fossil fuels, as well as their important role in materials, food, and pharmaceutical synthesis, it is unlikely that these renewable energy sources will fundamentally replace or substitute for fossil fuels in the foreseeable future. Therefore, researchers have turned their attention to the exploitation of unconventional fossil fuels, such as oil sands, heavy oil, and oil shale, which are abundant and widely distributed. The development and utilization of these fossil fuels has become a major issue of widespread concern in the industry.

[0003] Among various unconventional fossil energy sources, oil shale research is currently a key focus and hot topic for researchers in various fields. The proven reserves of oil shale in strata are currently equivalent to 689 billion tons of shale oil, approximately four times the global proven crude oil reserves. Simply put, oil shale is a combustible rock, a sedimentary rock with an inorganic mineral framework and rich in solid combustible organic matter (kerogen). Kerogen organic matter is the main precursor to oil-forming substances in oil shale, and its ideal hydrogen-to-carbon ratio facilitates its gaseous or liquid fuel conversion through various means.

[0004] Pyrolysis is a common processing method for oil shale, transforming it into smaller molecules. However, oil shale has a complex structure containing numerous heteroatoms and inorganic minerals, resulting in high energy consumption and high processing costs during pyrolysis. Therefore, producing high-quality petroleum-like fuels and high-value-added chemicals through low-energy oil shale pyrolysis is an important and worthwhile research topic.

[0005] Introducing catalysts into the catalytic pyrolysis of oil shale can not only solve the problem of high energy consumption in the reaction process and reduce the activation energy, but also improve product selectivity and reaction rate, and reduce heteroatom mass, thereby improving the quality of the produced shale oil and producing high-value-added chemicals. Common catalysts for oil shale catalytic pyrolysis can be divided into natural catalysts and synthetic catalysts. Natural catalysts include illite, kaolin, and pyrite, which are inexpensive, but the pretreatment process is complex and the product selectivity is poor. Synthetic catalysts include inorganic metal salts, metal oxides, and molecular sieve catalysts, which have good selectivity and high activity, but the production cost is high and they are prone to coking and deactivation during the reaction. Considering the strategic significance of oil shale in the energy and resource fields, it is very important to study oil shale pyrolysis and develop a low-cost, readily available, and highly effective catalyst. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of expensive, complex, and poor catalytic activity of catalysts currently used in the pyrolysis of fossil energy or biomass, and to provide a metal-based solid acid catalyst and its application in the processing of fossil energy or biomass, a method for catalytic pyrolysis of fossil energy or biomass, and a method for two-stage catalytic pyrolysis of fossil energy or biomass (especially oil shale).

[0007] The metal-based solid acid catalyst researched by the inventors comprises an active component, including titanium. When this metal-based solid acid catalyst is used to process and treat fossil fuels and biomass, especially oil shale, the introduction of this catalyst into the oil shale pyrolysis system significantly reduces the activation energy of the pyrolysis reaction compared to existing technologies. Furthermore, the catalyst's selectivity reduces the content of heteroatom compounds in the obtained pyrolysis products, increases the hydrocarbon content, and enhances the content of valuable platform chemicals.

[0008] To achieve the above objectives, a first aspect of the present invention provides a metal-based solid acid catalyst, wherein the metal-based solid acid catalyst comprises an active component, the active component including titanium;

[0009] The general formula of the metal-based solid acid catalyst is TiOSO4·xH2O, where x≥0.

[0010] The second aspect of the present invention provides the application of the aforementioned metal-based solid acid catalyst in the processing and treatment of fossil energy or biomass.

[0011] A third aspect of the present invention provides a method for catalytic pyrolysis of fossil energy or biomass, wherein the method comprises: contacting a metal-based solid acid catalyst with fossil energy or biomass and carrying out a pyrolysis reaction under an inert gas, oxygen-deficient or non-oxidizing gas atmosphere to obtain pyrolysis products;

[0012] The metal-based solid acid catalyst contains an active component, which includes titanium.

[0013] The general formula of the metal-based solid acid catalyst is TiOSO4·xH2O, where x≥0.

[0014] The fourth aspect of the present invention provides a method for catalytic pyrolysis of fossil energy or biomass in two stages, wherein a metal-based solid acid catalyst is contacted with fossil energy or biomass in an atmosphere of inert gas, oxygen deficiency or non-oxidizing gas, and the fossil energy or biomass is subjected to catalytic pyrolysis reaction in a first stage and a second stage.

[0015] Wherein, the pyrolysis temperature of the first stage is lower than the pyrolysis temperature of the second stage;

[0016] The metal-based solid acid catalyst contains an active component, which includes titanium.

[0017] The general formula of the metal-based solid acid catalyst is TiOSO4·xH2O, where x≥0.

[0018] Depending on the pyrolysis temperature, catalytic pyrolysis can improve the quality of pyrolysis products from fossil fuels or biomass (especially oil shale), or it can prioritize the production of several value-added platform chemicals that have attracted widespread attention from academia and industry.

[0019] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0020] (1) In the technical solution provided by the present invention, titanium is selected as the active component of the metal-based solid acid catalyst. On the one hand, the introduction of the metal-based solid acid catalyst can significantly reduce the activation energy of the pyrolysis reaction of fossil energy or biomass (especially oil shale); on the other hand, high-quality petroleum-like fuels or valuable platform chemicals can be produced through the catalytic pyrolysis of fossil energy or biomass (especially oil shale). That is, the selective reduction of heteroatom compounds in the pyrolysis products of fossil energy or biomass (especially oil shale) and the increase of hydrocarbon content can be achieved by the catalyst, thereby increasing the content of valuable platform chemicals.

[0021] (2) In this invention, by using a metal-based solid acid catalyst for the catalytic pyrolysis of oil shale, the activation energy of the oil shale pyrolysis reaction is reduced by 10.4% compared with the non-catalytic system of oil shale. In addition, the catalytic and non-catalytic systems of oil shale undergo two-stage pyrolysis at lower and higher temperatures.

[0022] The inventors of this invention discovered that when oil shale undergoes a first-stage pyrolysis (e.g., 438°C) in the presence of this catalyst, compared to a non-catalyzed system of oil shale, the contents of nitrogen-containing compounds, oxygen-containing compounds, and medium / long-chain aliphatic hydrocarbons are reduced by 41.2%, 36.5%, and 22.7%, respectively. Furthermore, the hydrocarbon content increases by 12.9%, which is beneficial for producing high-quality petroleum-like fuels, while short-chain aliphatic hydrocarbons (≤C...) are also reduced. 13 The content of α-olefins increased significantly by 285.7%, which is beneficial for the formation of light petroleum-like fuels. The inventors of this invention noted that the content of α-olefins, a valuable unit for producing various functional polyolefins, increased from 0% to 6.4%. Even more surprisingly, the content of thiophene compounds increased significantly by 329.7%. Thiophene compounds are valuable units widely used in flexible and foldable optoelectronic devices, photovoltaics, and nonlinear optics.

[0023] When oil shale undergoes a second-stage pyrolysis (e.g., at 590°C) in the presence of this catalyst, compared to the non-catalyzed system, the content of heteroatom compounds decreases significantly by 36.5%, while the content of hydrocarbon compounds increases from 69.3% to as high as 80.5%, including short-chain aliphatic hydrocarbons (≤C). 13 The contents of 1-hexene and 1-heptene increased significantly by 39.7% and decreased by 27.1%, respectively, indicating a significant improvement in the quality of oil shale catalytic pyrolysis products. Furthermore, the content of toluene, an important platform solvent / component / intermediate widely used in chemical engineering, increased significantly by 237.5%. The inventors also noted that the contents of 1-hexene and 1-heptene increased significantly by 210.0% and 412.5%, respectively, and these are important units / precursors for the production of polyethylene or various functional molecules / materials. Attached Figure Description

[0024] Figure 1 A is the PXRD diffraction pattern of the titanium oxysulfate catalyst provided by this invention; Figure 1 B is the FTIR spectrum of the titanium oxysulfate catalyst; Figure 1 C-1E is the XPS spectrum of the titanium oxysulfate catalyst;

[0025] Figure 2 A represents the TG curves of the original oil shale pyrolysis system without the titanium oxysulfate catalyst at different heating rates; Figure 2 B represents the DTG curves of the original oil shale pyrolysis system without the sulfuric acid titanium oxycatalyst at different heating rates; Figure 2 C represents the TG curves of the oil shale pyrolysis system containing sulfuric acid titanium oxycatalyst at different heating rates; Figure 2 D represents the DTG curves of the oil shale pyrolysis system containing sulfuric acid titanium oxycatalyst at different heating rates;

[0026] Figure 3 A represents the original oil shale pyrolysis system without the titanium oxysulfate catalyst, based on the KAS approximation equation fitted with ln(β / T). 2 α ) and 1 / T α The regression plot; Figure 3 B represents the ln(β / T) of the oil shale pyrolysis system containing a titanium oxysulfate catalyst, fitted based on the KAS approximation equation. 2 α ) and 1 / T α The regression plot; Figure 3 C represents different oil shale pyrolysis systems obtained based on the KAS method, and E represents... α As a function distribution graph of α;

[0027] Figure 4 A and Figure 4 B represents the TG and DTG curves of different oil shale pyrolysis systems at a heating rate of 10 K / min. Figure 4 C and Figure 4 D represents the TG and DTG curves of different oil shale pyrolysis systems at a heating rate of 15 K / min. Figure 4 E and Figure 4 F represents the TG and DTG curves of different oil shale pyrolysis systems at a heating rate of 20 K / min. Figure 4 G and Figure 4 H represents the TG and DTG curves of different oil shale pyrolysis systems at a heating rate of 25 K / min. Figure 4 I and Figure 4 J represents the TG and DTG curves of different oil shale pyrolysis systems at a heating rate of 30 K / min.

[0028] Figure 5 A represents the Py-EGA-MS plots of different oil shale pyrolysis systems; Figure 5 B is the MS diagram of the products generated in the first peak region of different oil shale pyrolysis systems; Figure 5 C is the MS diagram of the products generated in the second peak region of different oil shale pyrolysis systems;

[0029] Figure 6 A is the TIC diagram of the products obtained from the first stage pyrolysis reaction of different oil shale pyrolysis systems; Figure 6 B is a schematic diagram showing the distribution of hydrocarbon and non-hydrocarbon compounds obtained from the first stage pyrolysis reaction of different oil shale pyrolysis systems;

[0030] Figure 7 A-7C is a schematic diagram showing the distribution of each component in the products obtained from the first-stage pyrolysis reaction of different oil shale pyrolysis systems;

[0031] Figure 8 A is the TIC diagram of the products obtained from the second-stage pyrolysis reaction of different oil shale pyrolysis systems; Figure 8 B is a schematic diagram showing the distribution of hydrocarbon and non-hydrocarbon compounds obtained from the second-stage pyrolysis reaction of different oil shale pyrolysis systems; Figure 8 C is a schematic diagram showing the distribution of N, O, S and thiophene compounds obtained from the second-stage pyrolysis reaction of different oil shale pyrolysis systems;

[0032] Figure 9 A-9C is a schematic diagram showing the distribution of each component in the products obtained from the second-stage pyrolysis reaction of different oil shale pyrolysis systems;

[0033] Figure 10 The image shows the Py-FTIR spectrum of the titanium oxysulfate catalyst. Detailed Implementation

[0034] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0035] The first aspect of the present invention provides a metal-based solid acid catalyst, wherein the metal-based solid acid catalyst comprises an active component, the active component including titanium;

[0036] The general formula of the metal-based solid acid catalyst is TiOSO4·xH2O, where x≥0.

[0037] In some embodiments of the present invention, preferably, in the metal-based solid acid catalyst, the concentration of 0 μmol / g < β-acid ≤ 1 × 10⁻⁶. 7 μmol / g, 0 μmol / g < L-acid concentration ≤ 1 × 10 7 μmol / g; more preferably, 0.001 μmol / g ≤ β-acid concentration ≤ 2000 μmol / g, 0.001 μmol / g ≤ L-acid concentration ≤ 1000 μmol / g; more preferably, 0.01 μmol / g ≤ β-acid concentration ≤ 1000 μmol / g, 0.01 μmol / g ≤ L-acid concentration ≤ 500 μmol / g; most preferably, 0.1 μmol / g ≤ β-acid concentration ≤ 200 μmol / g, 0.1 μmol / g ≤ L-acid concentration ≤ 100 μmol / g. In this invention, β-acid is... Acids; L-acids are Lewis acids.

[0038] In the catalytic pyrolysis of fossil fuels or biomass (especially oil shale), the Lewis (L-) acid and / or... Acids can serve as catalytically active sites. Although there is currently no clear definition or consensus on the different roles of β- and L-acid sites in the pyrolysis of fossil fuels or biomass (especially oil shale), the distribution variations of products induced by acid catalysts in the pyrolysis of fossil fuels or biomass (especially oil shale) are often the result of synergistic and competitive interactions between these two acidic sites. The direct coordination of tetravalent titanium cations with electron-withdrawing sulfate groups transfers electrons from the former to the latter, creating L-acid sites in titanium oxysulfate or titanium oxysulfate hydrates. Furthermore, the coexistence of surface-chemisorbed water molecules and surface hydroxyl groups may facilitate the formation of mobile protons on the surface of titanium oxysulfate or titanium oxysulfate hydrates, leading to the creation of β-acid sites. Therefore, both L-acid and β-acid sites exist on the surface of titanium oxysulfate or titanium oxysulfate hydrates. Thus, it is reasonable to propose that titanium oxysulfate or titanium oxysulfate hydrates are suitable catalysts for the pyrolysis of fossil fuels or biomass (especially oil shale).

[0039] The second aspect of the present invention provides the application of the aforementioned metal-based solid acid catalyst in the processing and treatment of fossil energy or biomass.

[0040] In some embodiments of the present invention, preferably, the fossil energy source is selected from at least one of petroleum, coal, heavy oil, oil shale, shale oil and oil sands, and preferably oil shale.

[0041] In some embodiments of the present invention, preferably, the biomass is selected from at least one of solid waste, agricultural resources, wastewater, animal manure, and forestry resources.

[0042] In this invention, the range of processing and treatment methods is relatively wide. Preferably, the processing and treatment method is catalytic pyrolysis.

[0043] The metal-based solid acid catalyst researched by the inventors comprises an active component, including titanium. When this metal-based solid acid catalyst is used to process and treat fossil fuels and biomass, especially oil shale, the introduction of this catalyst into a pyrolysis system significantly reduces the activation energy of the pyrolysis reaction compared to existing technologies. Furthermore, the selective nature of this catalyst reduces the content of heteroatom compounds in the obtained pyrolysis products, increases the content of hydrocarbons, and enhances the content of valuable platform chemicals.

[0044] In this invention, unless otherwise specified, the pyrolysis activation energy parameter is obtained from the relationship curves between the weight loss rate and temperature of substances such as fossil energy and biomass.

[0045] In this invention, unless otherwise specified, the activation energy change rate parameter is obtained by analyzing the relationship curves between weight loss rate and temperature of the pyrolysis system containing a metal-based solid acid catalyst and the pyrolysis system without a metal-based solid acid catalyst, thus obtaining the pyrolysis activation energy of each system. The activation energies of the pyrolysis system containing a metal-based solid acid catalyst and the pyrolysis system without a metal-based solid acid catalyst are then compared and analyzed.

[0046] A third aspect of the present invention provides a method for catalytic pyrolysis of fossil energy or biomass, wherein the method comprises: contacting a metal-based solid acid catalyst with fossil energy or biomass and carrying out a pyrolysis reaction under an inert gas, oxygen-deficient or non-oxidizing gas atmosphere to obtain pyrolysis products;

[0047] The metal-based solid acid catalyst contains an active component, which includes titanium.

[0048] The general formula of the metal-based solid acid catalyst is TiOSO4·xH2O, where x≥0.

[0049] In some embodiments of the present invention, preferably, in the metal-based solid acid catalyst, the concentration of 0 μmol / g < β-acid ≤ 1 × 10⁻⁶. 7 μmol / g, 0 μmol / g < L-acid concentration ≤ 1 × 10 7 μmol / g; more preferably, 0.001 μmol / g ≤ β-acid concentration ≤ 2000 μmol / g, 0.001 μmol / g ≤ L-acid concentration ≤ 1000 μmol / g; more preferably, 0.01 μmol / g ≤ β-acid concentration ≤ 1000 μmol / g, 0.01 μmol / g ≤ L-acid concentration ≤ 500 μmol / g; most preferably, 0.1 μmol / g ≤ β-acid concentration ≤ 200 μmol / g, 0.1 μmol / g ≤ L-acid concentration ≤ 100 μmol / g.

[0050] Using the titanium oxysulfate or titanium oxysulfate hydrate catalyst described in this invention for catalytic pyrolysis of the reactants can significantly reduce the activation energy of the pyrolysis reaction. Furthermore, the selectivity of this catalyst can reduce the content of heteroatom compounds in the obtained pyrolysis products, increase the content of hydrocarbons, and increase the content of valuable platform chemicals.

[0051] In this invention, the reactants include fossil fuels and biomass. Unless otherwise specified, the types of fossil fuels and biomass are as defined above, and will not be elaborated further here.

[0052] In some embodiments of the present invention, preferably, the method includes the following steps:

[0053] (1) Under an atmosphere of inert gas, oxygen deficiency or non-oxidizing gas, the metal-based solid acid catalyst is mixed with fossil energy or biomass to obtain a mixture;

[0054] (2) The mixture is subjected to a pyrolysis reaction in an atmosphere of inert gas, oxygen deficiency or non-oxidizing gas.

[0055] The above-mentioned catalytic pyrolysis method can significantly reduce the activation energy of the pyrolysis reaction. Furthermore, the selective use of this catalyst can reduce the content of heteroatom compounds in the obtained pyrolysis products, increase the content of hydrocarbons, and increase the content of valuable platform chemicals.

[0056] In this invention, the selection range for the mixing method is relatively wide, as long as it can uniformly mix the metal-based solid acid catalyst and fossil energy or biomass. In some embodiments of this invention, the mixing method is selected from grinding / soaking.

[0057] In some embodiments of the present invention, the mixing time is generally 0-36h, for example 0h, 1h, 2h, 3h, 6h, 12h, 18h, 24h, 30h, 36h, and any value within the range of any two of the above values, preferably 0-6h.

[0058] In some embodiments of the present invention, the metal-based solid acid catalyst comprises an active component, i.e., the chemical formula of the catalyst is TiOSO4·xH2O, where x≥0. The metal-based solid acid catalyst is mixed in solid powder form with fossil fuels or biomass, and then ground to obtain an average particle size of 0.00001-1×10⁻⁶. 12 A mixture of μm particles. The average particle size of the fossil-based energy / biomass or metal-based solid acid catalyst is 0.0001-1×10⁻⁶. 5 μm, preferably 0.003-700μm.

[0059] In this invention, unless otherwise specified, when the pyrolysis reaction is carried out on land, there are certain requirements for the average particle size of the fossil-based energy / biomass or metal-based solid acid catalyst; that is, the average particle size of the fossil-based energy / biomass or metal-based solid acid catalyst is 0.0001-1×10⁻⁶. 5μm, preferably 0.003-700 μm; when the pyrolysis reaction is carried out underground, there are no special requirements for the average particle size of the metal-based solid acid catalyst. The main reason is that when the pyrolysis reaction is carried out underground, the underground ore is cracked mainly by underground explosion or fracturing. The particle size of the ore can be hundreds of meters or even larger. This is equivalent to the formation of rocks of various sizes due to underground explosion. The metal-based solid acid catalyst is attached to the surface of the rock that generates oil / gas dominant channels underground.

[0060] In some embodiments of the present invention, preferably, the weight ratio of the metal-based solid acid catalyst to the reactant is 1:8000-20:1, more preferably 1:2000-3:1. The weight of the metal-based solid acid catalyst is based on the weight of the active component, i.e., the weight of TiOSO4·xH2O (x≥0). In the present invention, controlling the above weight ratio within a specific range allows the pyrolysis reaction to proceed more completely.

[0061] In this invention, the range of conditions for the pyrolysis reaction is relatively wide.

[0062] In some embodiments of the present invention, preferably, the temperature of the pyrolysis reaction is 20-1000℃, for example 20℃, 50℃, 100℃, 200℃, 300℃, 400℃, 500℃, 600℃, 650℃, 700℃, 800℃, 900℃, 1000℃, and any value within any two of the above ranges, preferably 100-650℃.

[0063] In some embodiments of the present invention, preferably, the pyrolysis reaction time is 0.00001s to 7 years, for example, 0.00001s, 0.0001s, 0.001s, 0.1s, 1s, 5s, 5min, 1h, 15h, 2 days, 50 days, 1 year, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, and any value within any two of the above ranges, preferably 0.0001s to 48h.

[0064] In some embodiments of the present invention, preferably, the heating rate of the pyrolysis reaction is 0-8000℃ / s, for example 0℃ / s, 0.0001℃ / s, 0.01℃ / s, 0.1℃ / s, 1℃ / s, 5℃ / s, 10℃ / s, 50℃ / s, 200℃ / s, 600℃ / s, 1000℃ / s, 2000℃ / s, 4000℃ / s, 6000℃ / s, 8000℃ / s, and any value within any two of the above ranges, preferably 0-5000℃ / s.

[0065] In this invention, by controlling the conditions of the above-mentioned pyrolysis reaction within a specific range, the pyrolysis reaction can be carried out more completely.

[0066] Unless otherwise specified, the heating rate parameter of the pyrolysis reaction in this invention depends on the heating method. When using the Curie point heating method, the heating rate can be as high as 8000℃ / s, while when using other heating methods, the heating rate can be as low as 0.0001℃ / s. Furthermore, when the pyrolysis reaction is carried out at an isothermal temperature, the heating rate is 0℃ / s.

[0067] In this invention, unless otherwise specified, the duration of the pyrolysis reaction depends on the specific conditions. If the pyrolysis reaction is carried out underground, the reaction time can be 0.5-7 years, or even a few months or days.

[0068] In some embodiments of the present invention, the inert gas is selected from at least one of helium, nitrogen, neon, argon, krypton and xenon, preferably nitrogen.

[0069] In some embodiments of the present invention, the non-oxidizing gas is selected from at least one of carbon monoxide, carbon dioxide, gaseous water, and hydrogen.

[0070] In one specific embodiment of the present invention, the non-oxidizing gas or oxygen-deficient atmosphere may be an underground oxygen-deficient environment.

[0071] In some embodiments of the present invention, preferably, the pyrolysis reaction takes place above ground or underground.

[0072] In one specific embodiment of the present invention, preferably, if the pyrolysis reaction is carried out in an underground environment, the metal-based solid acid catalyst is directly transported underground for the reaction, or the metal-based solid acid catalyst is transported underground for the reaction by a fluid load.

[0073] In this invention, the range of fluids that can be selected is wide, including liquids and gases, such as organic solvents, nitrogen, water, air, carbon dioxide, carbon monoxide, helium, and hydrogen.

[0074] The method provided by this invention uses an active component containing titanium oxysulfate or titanium oxysulfate hydrate as a catalyst to react with fossil energy or biomass (especially oil shale) in an inert gas, non-oxidizing gas, or oxygen-deficient atmosphere. This method can significantly reduce the activation energy of the pyrolysis reaction. Furthermore, the selectivity of this catalyst can reduce the content of heteroatom compounds in the obtained pyrolysis products, increase the content of hydrocarbons, and increase the content of valuable platform chemicals.

[0075] A fourth aspect of the present invention provides a method for catalytic pyrolysis of fossil energy or biomass (especially oil shale) in two stages, wherein the method comprises: contacting a metal-based solid acid catalyst with fossil energy or biomass (especially oil shale) in an inert gas, oxygen-deficient or non-oxidizing gas atmosphere and carrying out a catalytic pyrolysis reaction of fossil energy or biomass (especially oil shale) in a first stage and a second stage.

[0076] Wherein, the pyrolysis temperature of the first stage is lower than the pyrolysis temperature of the second stage;

[0077] The metal-based solid acid catalyst contains an active component, which includes titanium.

[0078] The general formula of the metal-based solid acid catalyst is TiOSO4·xH2O, where x≥0.

[0079] Depending on the temperature of the catalytic pyrolysis reaction, the quality of pyrolysis products from fossil fuels or biomass (especially oil shale) can be improved. For example, heteroatom compounds can be removed, the content of hydrocarbons and short-chain aliphatic hydrocarbons can be increased, or the content of medium / long-chain aliphatic hydrocarbons can be reduced. Alternatively, several value-added platform chemicals that have attracted widespread attention from academia and industry can be prioritized for production.

[0080] In some embodiments of the present invention, preferably, in the metal-based solid acid catalyst, the concentration of 0 μmol / g < β-acid ≤ 1 × 10⁻⁶. 7 μmol / g, 0 μmol / g < L-acid concentration ≤ 1 × 10 7 μmol / g; more preferably, 0.001 μmol / g ≤ β-acid concentration ≤ 2000 μmol / g, 0.001 μmol / g ≤ L-acid concentration ≤ 1000 μmol / g; more preferably, 0.01 μmol / g ≤ β-acid concentration ≤ 1000 μmol / g, 0.01 μmol / g ≤ L-acid concentration ≤ 500 μmol / g; most preferably, 0.1 μmol / g ≤ β-acid concentration ≤ 200 μmol / g, 0.1 μmol / g ≤ L-acid concentration ≤ 100 μmol / g.

[0081] In this invention, the reactants include fossil fuels and biomass. Unless otherwise specified, the types of fossil fuels and biomass are as defined above, and will not be elaborated further here.

[0082] In some embodiments of the present invention, preferably, the method includes the following steps:

[0083] (1') Under an atmosphere of inert gas, oxygen-deficient or non-oxidizing gas, the metal-based solid acid catalyst is mixed with fossil energy or biomass (especially oil shale) to obtain a mixture;

[0084] (2') In an atmosphere of inert gas, oxygen-deficient or non-oxidizing gas, the mixture is subjected to catalytic pyrolysis of fossil energy or biomass (especially oil shale) through a first-stage pyrolysis and a second-stage pyrolysis.

[0085] In this invention, the selection range for the mixing method in step (1') is relatively wide, as long as the metal-based solid acid catalyst and fossil energy or biomass (especially oil shale) are mixed evenly. In some embodiments of this invention, the mixing method is selected from grinding / soaking.

[0086] In some embodiments of the present invention, in step (1'), the mixing time is generally 0-36h, for example 0h, 1h, 2h, 3h, 6h, 12h, 18h, 24h, 30h, 36h, and any value within the range of any two of the above values, preferably 0-6h.

[0087] In some embodiments of the present invention, the metal-based solid acid catalyst comprises an active component, i.e., the chemical formula of the catalyst is TiOSO4·xH2O, where x≥0. The metal-based solid acid catalyst is mixed in solid powder form with fossil fuels or biomass (especially oil shale), and then ground to obtain an average particle size of 1×10⁻⁶. 12 -1×10 5 A mixture of μm particles. The average particle size of the fossil-based energy / biomass (especially oil shale) or metal-based solid acid catalyst is 1 × 10⁻⁶. 5 -1×10 4 μm, preferably 700-0.003μm.

[0088] Unless otherwise specified, in this invention, when the catalytic pyrolysis reaction is carried out on land, there are certain requirements for the average particle size of the fossil-based energy / biomass (especially oil shale) or metal-based solid acid catalyst; that is, the average particle size of the fossil-based energy / biomass (especially oil shale) or metal-based solid acid catalyst is 0.00001-1×10⁻⁶. 5μm, preferably 0.003-700 μm; when the catalytic pyrolysis reaction is carried out underground, there is no special requirement for the average particle size of the metal-based solid acid catalyst. The main reason is that when the pyrolysis reaction is carried out underground, the underground ore is cracked mainly by underground explosion or fracturing. The particle size range of the ore can be hundreds of meters or even larger. This is equivalent to the formation of rocks of various sizes due to underground explosion. The metal-based solid acid catalyst is attached to the surface of the rock that generates oil / gas dominant channels underground.

[0089] In some embodiments of the present invention, preferably, the weight ratio of the metal-based solid acid catalyst to fossil energy or biomass (especially oil shale) is 1:8000-20:1, more preferably 1:2000-3:1. The weight of the metal-based solid acid catalyst is based on the weight of the active component, i.e., the weight of TiOSO4·xH2O (x≥0).

[0090] In this invention, the range of selectable conditions for the catalytic pyrolysis reaction is relatively wide.

[0091] In some embodiments of the present invention, preferably, the pyrolysis temperature of the first stage is 20-550℃, for example 20℃, 50℃, 100℃, 200℃, 300℃, 400℃, 500℃, 550℃, and any value within the range of any two of the above values, preferably 100-500℃.

[0092] In some embodiments of the present invention, preferably, the pyrolysis temperature of the second stage is 200-600℃, for example 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, and any value within the range of any two of the above values, preferably 250-550℃.

[0093] In some embodiments of the present invention, preferably, the pyrolysis time of the first stage and the second stage are each independently between 0.00001s and 7 years, for example, 0.00001s, 0.0001s, 0.001s, 0.01s, 1s, 5s, 5min, 1h, 15h, 2 days, 50 days, 1 year, 2 years, 3 years, 4 years, 5 years, 6 years, 7 years, and any value within the range of any two of the above values, preferably between 0.0001s and 48h.

[0094] In some embodiments of the present invention, preferably, the heating rate of the first stage and the second stage are each independently 0-8000℃ / s, for example, 0℃ / s, 5℃ / s, 10℃ / s, 50℃ / s, 200℃ / s, 600℃ / s, 1000℃ / s, 2000℃ / s, 4000℃ / s, 6000℃ / s, 8000℃ / s, and any value within the range of any two of the above values, preferably 0-5000℃ / s.

[0095] In this invention, by controlling the conditions of the above-mentioned catalytic pyrolysis reaction within a specific range, the pyrolysis reaction can be carried out more completely.

[0096] Unless otherwise specified, the heating rate parameter of the catalytic pyrolysis reaction in this invention depends on the heating method. When using the Curie point heating method, the heating rate can be as high as 8000℃ / s, while when using other heating methods, the heating rate can be as low as 0.0001℃ / s. Furthermore, when the pyrolysis reaction is carried out at an isothermal temperature, the heating rate parameter is 0℃ / s.

[0097] Unless otherwise specified, the duration of the catalytic pyrolysis reaction in this invention depends on the specific conditions. If the pyrolysis reaction is carried out underground, the duration of the catalytic pyrolysis reaction can be 0.5-7 years, or even a few months or days.

[0098] In some embodiments of the present invention, the inert gas is selected from at least one of helium, nitrogen, neon, argon, krypton and xenon, preferably helium.

[0099] In some embodiments of the present invention, the non-oxidizing gas is selected from at least one of carbon monoxide, carbon dioxide, gaseous water, and hydrogen.

[0100] In one specific embodiment of the present invention, the non-oxidizing gas or oxygen-deficient atmosphere may be an underground oxygen-deficient environment.

[0101] In some embodiments of the present invention, preferably, the pyrolysis reaction is carried out above ground or underground.

[0102] In one specific embodiment of the present invention, preferably, if the catalytic pyrolysis reaction is carried out in an underground environment, the metal-based solid acid catalyst is directly transported underground for the reaction, or the metal-based solid acid catalyst is transported underground for the reaction by a fluid load.

[0103] In this invention, the range of fluids that can be selected is wide, including liquids and gases, such as organic solvents, nitrogen, water, air, carbon dioxide, carbon monoxide, helium, and hydrogen.

[0104] The method provided by this invention uses an active component containing titanium oxysulfate or titanium oxysulfate hydrate as a catalyst to catalytically pyrolyze fossil fuels or biomass (especially oil shale) in an inert gas, oxygen-deficient, or non-oxidizing gas atmosphere through a two-stage process at lower and higher temperatures. Depending on the pyrolysis temperature, catalytic pyrolysis can improve the quality of the pyrolysis products of fossil fuels or biomass (especially oil shale). For example, it can remove heteroatom compounds, increase the content of hydrocarbons and short-chain aliphatic hydrocarbons, or reduce the content of medium / long-chain aliphatic hydrocarbons. Alternatively, it can prioritize the production of several value-added platform chemicals that have attracted widespread attention from academia and industry.

[0105] The present invention will be described in detail below through embodiments.

[0106] Example 1

[0107] The original titanium oxysulfate hydrate was calcined in air at 500℃ to obtain a titanium oxysulfate catalyst, which was then subjected to powder X-ray diffraction (PXRD) analysis. Figure 1 As shown in Figure A, its diffraction peaks match well with the diffraction pattern of standard hexagonal phase TiOSO4 (JCPDS 49-0467), indicating that the sample is TiOSO4.

[0108] Fourier transform infrared spectroscopy (FTIR) was performed on the above-mentioned titanium oxysulfate catalyst (TiOSO4), as follows: Figure 1 As shown in Figure B, the catalyst exhibits numerous chemically adsorbed water molecules and surface hydroxyl groups, as well as Ti-O bonds, SO, S=O bonds, and OO bonds, indicating the possible presence of β-acid and L-acid sites in the system.

[0109] X-ray photoelectron spectroscopy (XPS) was performed on the above-mentioned titanium oxysulfate catalyst (TiOSO4), as follows: Figure 1 As shown in C-1E, the catalyst contains tetravalent titanium ions, which are in an electron-deficient state and can act as L-acids; the sulfate groups can also introduce many hydroxyl groups, thus acting as Brønsted acid (B-acid). Therefore, TiOSO4 may contain both Brønsted and L-acid sites, which could provide a good catalytic effect for the catalytic pyrolysis of oil shale.

[0110] To evaluate the catalytic performance of the above-mentioned titanium oxysulfate catalyst for the pyrolysis of oil shale, thermogravimetric (TG) analysis experiments were conducted with and without the participation of the TiOSO4 catalyst.

[0111] After introducing the TiOSO4 catalyst, 10 mg of oil shale with an average particle size ≤74 μm and 1 mg of TiOSO4 catalyst were mixed evenly and spread evenly in a crucible. The heating rates were 10 K / min (10 K / min = 1 / 6 °C / s, the same applies below), 15 K / min, 20 K / min, 25 K / min, and 30 K / min, with a temperature range of 35-980 °C. During the experiment, the carrier gas was dry, high-purity nitrogen, with a flow rate maintained at 50 mL / min (the flow rates of purge gas and protective gas were both 25 mL / min). For the oil shale pyrolysis system without the TiOSO4 catalyst, except for the TG experiment with 10 mg of oil shale powder with an average particle size ≤74 μm, all other conditions were the same as the TG experiment conditions with the TiOSO4 catalyst. Each experiment was performed three times under the same conditions to ensure the repeatability and reliability of the results.

[0112] Based on TG analysis, a series of TG values ​​obtained at heating rates of 10 K / min, 15 K / min, 20 K / min, 25 K / min, and 30 K / min were analyzed. Figure 2 A and Figure 2 C) and DTG Figure 2 B and Figure 2 D) The data were processed and analyzed, and the catalytic performance of TiOSO4 catalyst for oil shale pyrolysis was estimated using the KAS method. The oil shale pyrolysis systems with and without TiOSO4 catalyst are shown below. Figure 3 A, Figure 3 B, after introducing this catalyst, as Figure 3 As shown in C, calculations using the KAS method indicate that the activation energy of the oil shale pyrolysis reaction decreased by 10.4%. The approximate equation for the KAS method is shown in equation (1):

[0113]

[0114] like Figure 4 As shown, a series of TG (triglycerides) were obtained from different pyrolysis systems at different heating rates. Figure 4 A, Figure 4 C Figure 4 E, Figure 4 G and Figure 4 I) and DTG Figure 4 B Figure 4 D、 Figure 4 F, Figure 4 H and Figure 4 The data were analyzed, and the study found that the introduction of TiOSO4 catalyst can effectively promote the pyrolysis of organic matter in oil shale and has good anti-coking performance. The anti-coking performance of this catalyst will be further studied below.

[0115] In addition, we conducted temperature-programmable pyrolysis experiments (Py-EGA-MS) on oil shale pyrolysis systems with and without TiOSO4 catalyst. After introducing TiOSO4 catalyst, 1 mg of oil shale with an average particle size ≤74 μm and 0.1 mg of TiOSO4 catalyst were mixed uniformly and placed in a pyrolysis vessel. The temperature of the microfurnace in the pyrolysis unit was increased from 55 °C to 850 °C at a heating rate of 10 K / min. During the experiment, dry high-purity helium was used as the carrier gas, with a total flow rate of 12.1 mL / min, a column flow rate of 0.82 mL / min, and a purge flow rate of 3 mL / min. The column inlet pressure was 80 kPa, and the m / z range was 10–800. During the experiment, the temperatures of the GC inlet, column oven, and interface between the GC and MS were maintained at 300 °C to prevent condensation of the pyrolysis products, while the ion source was maintained at 250 °C. For the oil shale pyrolysis system without the TiOSO4 catalyst, except for Py-EGA-MS experiments using 1 mg of oil shale powder with an average particle size ≤74 μm, all other conditions were the same as those for Py-EGA-MS experiments without the catalyst. Each experiment was performed three times under the same conditions to ensure the repeatability and reliability of the results.

[0116] like Figure 5 As shown in Figure A, Py-EGA-MS studies indicate that qualitative information about the volatile components can be obtained by extracting the mass spectra of the desired pyrolysis stage. After the pyrolysis of oil shale, two main peaks are observed. The first peak (the preceding peak) primarily corresponds to the pyrolysis of organic matter, while the second peak (the following peak) primarily corresponds to the pyrolysis of inorganic matter. With the introduction of the TiOSO4 catalyst, the highest point of the organic matter pyrolysis peak in oil shale shifts significantly to the lower temperature region, and the peak intensity of the total ion chromatogram increases. This indicates that TiOSO4 can indeed improve the conversion rate, enabling more organic matter to be converted into oil and gas products.

[0117] like Figure 5 As shown in Figure B, the signal in the mass spectrum of the pyrolysis products, indicated by the first peak region of the total ion chromatography (TIC) curve in Py-EGA-MS, is complex but clearly evident. Further analysis reveals mass fragments with m / z values ​​of 43+14n (n = 0, 1, 2, 3, etc.) and 41+14n (n = 0, 1, 2, 3, etc.), which are typically ion fragments of aliphatic hydrocarbon chains. Additionally, the ion fragment with m / z 81 is a fragment of alkyl-substituted cyclohexene, and the ion fragments with m / z 95 and 109 are fragments of aromatic compounds.

[0118] In addition, such as Figure 5 As shown in C, the mass spectra of the volatiles generated in the second peak region mainly yielded signals with m / z values ​​of 12, 16, 28, and 44, which are well matched with the standard mass spectrum of CO2, while the signals of other fragments were relatively weak.

[0119] We also analyzed the product distribution of oil shale pyrolysis systems with or without TiOSO4 catalyst using rapid pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) to further investigate the catalytic effect of this catalyst on oil shale pyrolysis. During the experiment, dry high-purity helium was used as the carrier gas at a total flow rate of 18.1 mL / min, with a small portion of helium introduced into the molten silica GC column after separation at a flow rate of 1.37 mL / min. The mass ratio of oil shale to TiOSO4 catalyst was 10:1, and the m / z range was 50-550. Oil shale powder with or without TiOSO4 catalyst was placed in a sample cup and then placed in a pyrolysis furnace at a preset temperature for 6 s. During the experiment, the GC column temperature was initially maintained at 50 °C for 5 min; then, the temperature was increased from 50 °C to 250 °C at a heating rate of 3 °C / min; finally, it was maintained at 250 °C for 20 min. Each experiment was performed three times under identical conditions to ensure the reproducibility and reliability of the results. Qualitative matching of chromatographic peaks observed in total ion chromatography (TIC) was performed by comparing peaks in the MS spectra with peaks in the National Institute of Standards and Technology (NIST) mass spectrometry database. Peak area integration and data analysis were performed using GC-MS Postrun Analysis (GCMSsolution Version 4.3) software.

[0120] We further investigated the catalytic performance of the catalyst in the pyrolysis of oil shale using both non-catalytic and catalytic systems during a two-stage pyrolysis process consisting of low and high temperatures, respectively. For example... Figure 6 As shown in Figure A, when oil shale undergoes the first stage (e.g., 438℃) pyrolysis in the presence of a TiOSO4 catalyst, the intensity and number of the first organic matter total ion chromatogram peaks significantly increase. This indicates that TiOSO4 can indeed improve the conversion rate, enabling more organic matter to be converted into oil and gas products, and can also significantly alter the distribution of pyrolysis products. Figure 6 As shown in B, after introducing the TiOSO4 catalyst, hydrocarbons increased from 35.7% to 40.3%, while non-hydrocarbon compounds decreased from 64.3% to 59.7%.

[0121] Further analysis of the pyrolysis products showed that, for example Figure 7As shown in Figure A, after introducing the TiOSO4 catalyst, the contents of nitrogen-containing and oxygen-containing compounds decreased from 6.8% to 4.0% (a reduction of 41.2%) and significantly from 63.5% to 40.3% (a marked reduction of 36.5%), respectively. However, as one of the more difficult heteroatom compounds to process in petroleum-like fuels, the content of sulfur-containing compounds did not decrease; instead, it increased from 6.6% to 15.9%, an increase of 140.9%. This results in a relatively small overall reduction in heteroatom compounds, which we find regrettable. However, further analysis of the sulfur-containing compounds revealed that the content of thiophene compounds increased significantly from 3.7% to 15.9%, a significant increase of 329.7%, especially 2-methylthiophene, whose content increased from 0% to 8.1%. This is interesting because, despite the challenging nature of sulfur-containing compounds, thiophene compounds are important building blocks widely used in flexible and foldable optoelectronic devices, nonlinear optics, photovoltaics, and other fields. This could provide a cheap and convenient scientific and practical space for the production of thiophene compounds.

[0122] In addition, such as Figure 7 As shown in Figure B, after introducing the TiOSO4 catalyst, the alkane content decreased from 32.7% to 14.1%, while the olefin content significantly increased from 0% to 14.1%. Another very important result is that the α-olefin content significantly increased from 0% to 6.4% after introducing the TiOSO4 catalyst. α-Olefins are industrially valuable building blocks or precursors used in the production of various types of polyethylene widely used in plastics, fibers, and elastomers, or in the production of various important linear aldehydes, short-chain fatty acids, alcohols, and functional surfactants. This may also provide a convenient route for the production of α-olefins. The aromatic hydrocarbon content significantly increased from 3.0% to 6.4%. Further analysis showed that after introducing the TiOSO4 catalyst, the monocyclic aromatic hydrocarbon content significantly increased from 3.0% to 6.2%, while the polycyclic aromatic hydrocarbon content only slightly increased from 0% to as low as 0.2%. This indicates that the catalyst exhibits high selectivity for monocyclic aromatic hydrocarbons (BAHs) but relatively low selectivity for polycyclic aromatic hydrocarbons (PAHs). The cleavage ability of Brønsted acid-catalyzed BAH side chains exceeds the further aromatization ability of L-acid-catalyzed side chains. Therefore, this catalyst demonstrates good anti-coking properties, as PAHs are typically precursors to coking. These changes result from the synergistic and competitive interactions between Brønsted acid and L-acid sites in the catalyst.

[0123] Further analysis shows that, for example Figure 7 As shown in C, after introducing the TiOSO4 catalyst, the short chain (≤C) 13 The content of aliphatic hydrocarbons increased from 2.8% to 10.8% (an increase of 285.7%), and the content of medium-chain (C) hydrocarbons... 14 -C 19 ) and long chains (C20 -C 25 and ≥C 26 The content of aliphatic hydrocarbons decreased from 18.8% to 17.6% and from 11.1% to 5.5% (a decrease of 50.5%), respectively. This may be a result of the acidic characteristics of the catalyst, through which the pyrolysis products of oil shale are converted from heavy oil to light oil.

[0124] After pyrolysis at low temperatures, the non-catalytic and catalytic systems of oil shale continue to undergo pyrolysis at high temperatures, such as at 590℃. Figure 8 As shown in Figure A, after the introduction of the TiOSO4 catalyst, similar to pyrolysis at low temperature, the intensity and number of chromatographic peaks also increased, indicating that TiOSO4 can indeed improve the conversion rate and change the product distribution at high temperature.

[0125] like Figure 8 As shown in B, after the introduction of the TiOSO4 catalyst, the percentage of hydrocarbons increased from 69.3% to 80.5% (an increase of 16.2%), while the percentage of non-hydrocarbons decreased from 30.7% to 19.5% (a decrease of 36.5%).

[0126] like Figure 8 As shown in Figure C, the reduction in non-hydrocarbon compound content after the introduction of the TiOSO4 catalyst is further reflected in the decrease in the content of nitrogen-containing, oxygen-containing, and sulfur-containing compounds from 0.6% to 0%, from 16.4% to 9.8%, and from 13.0% to 10.1%, respectively. At high temperatures, the content of thiophene compounds decreased from 11.9% to 9.7%. Although the content of thiophene compounds can be selectively increased at low temperatures, at high temperatures, with the assistance of the TiOSO4 catalyst, thiophene compounds are less stable and more prone to decomposition.

[0127] In addition, such as Figure 9 As shown in Figure A, after introducing the TiOSO4 catalyst, the content of alkanes in hydrocarbon compounds decreased from 16.5% to 11.6%, while the content of olefins increased from 34.9% to 40.0%. Importantly, the content of α-olefins increased from 27.6% to 35.3% (an increase of 27.9%). As very important α-olefins, the contents of 1-hexene and 1-heptene increased from 1.0% to 3.1% (a significant increase of 210.0%) and from 0.8% to 4.1% (a significant increase of 412.5%), respectively. Therefore, the TiOSO4 catalyst also exhibits good selectivity at high temperatures, which is beneficial for obtaining some valuable chemicals.

[0128] Further analysis shows that, for example Figure 9As shown in Figure B, after introducing the TiOSO4 catalyst, the aromatic hydrocarbon content increased from 11.0% to 17.5%, and the monocyclic aromatic hydrocarbon content increased from 11.0% to 16.9%, an increase of 53.6%. The polycyclic aromatic hydrocarbon content, however, increased only slightly, from 0% to 0.6%. This indicates that our catalyst exhibits significantly higher selectivity for monocyclic aromatic hydrocarbons than for polycyclic aromatic hydrocarbons, which also contributes to its better anti-coking properties. Furthermore, as a platform chemical with significant added value, the toluene content increased significantly from 1.6% to 5.4% (a remarkable increase of 237.5%). This result suggests that TiOSO4 catalysis of oil shale pyrolysis may provide a potential pathway for the production of the valuable platform chemical toluene.

[0129] We also investigated the changes in the carbon number distribution of aliphatic hydrocarbons caused by the second-stage rapid pyrolysis of oil shale using TiOSO4 at 590℃. For example... Figure 9 As shown in C, after introducing the TiOSO4 catalyst, the short chain (≤C) 13 The content of aliphatic hydrocarbons increased from 31.0% to 43.3% (an increase of 39.7%), and the content of medium-chain (C) hydrocarbons... 14 -C 19 ) and long chains (C 20 -C 25 and ≥C 26 The content of aliphatic hydrocarbons decreased from 20.1% to 14.4% (a reduction of 28.4%) and from 7.2% to 5.5% (a reduction of 23.6%), respectively. With this catalyst, medium / long-chain aliphatic hydrocarbons can be catalytically pyrolyzed to generate short-chain aliphatic hydrocarbons.

[0130] To further confirm the presence of acid sites on this TiOSO4, its pyridine adsorption was characterized by Fourier transform infrared spectroscopy (Py-FTIR). Figure 10 As shown by the solid line, the Py-FTIR curve of TiOSO4 obtained at a desorption temperature of 200℃ shows a value at 1540 cm⁻¹. -1 and 1447cm -1 The peaks at 1486 cm⁻¹ represent the absorption peaks of the β-acid and L-acid sites adsorbed by pyridine, respectively. -1 The peak at that position is the absorption peak resulting from the interaction of pyridine molecules with Brønsted (B) and Lewis (L) acid sites. Calculations showed that the concentrations of the L-acid and Brønsted (B) acid sites were 16.5 μmol / g and 35.0 μmol / g, respectively. Furthermore, as... Figure 10As shown by the dashed line, at a desorption temperature of 350 °C, the concentration of L-acid sites decreased slightly to 1.3 μmol / g (a significant decrease of 92.1%), while the concentration of Brønsted acid sites decreased significantly to 17.1 μmol / g (a decrease of 51.1%). Therefore, this indicates that there are more Brønsted acid sites than L-acid sites on the surface of the TiOSO4 catalyst, and that most Brønsted acid sites are relatively more acidic than L-acid sites.

[0131] In summary, inexpensive TiOSO4 can be directly used as a catalyst. Its catalytic performance in the two-stage pyrolysis of oil shale, consisting of low and high temperatures, was investigated. The results show that this catalyst can be upgraded and modified, depending on the pyrolysis temperature, to produce high-value-added platform chemicals, such as thiophene compounds, α-olefins, and toluene. Furthermore, the concentration and intensity of Brønsted (B) acid sites in the TiOSO4 catalyst are both higher than those of L-acid sites, indicating that the synergistic and competitive effects of B-acid and L-acid sites play a crucial role in the catalytic pyrolysis of oil shale.

[0132] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for two-stage catalytic pyrolysis of fossil fuels, characterized in that, The method includes: contacting a metal-based solid acid catalyst with fossil fuels in an inert, oxygen-deficient, or non-oxidizing gas atmosphere, and carrying out a catalytic pyrolysis reaction of the fossil fuels through a first stage and a second stage. The pyrolysis temperature of the first stage is lower than that of the second stage. The metal-based solid acid catalyst contains an active component, which includes titanium. The general formula of the metal-based solid acid catalyst is TiOSO4·xH2O, where x≥0; The fossil energy source is selected from oil shale; The non-oxidizing gas is selected from at least one of carbon monoxide, carbon dioxide, gaseous water, and hydrogen; the inert gas is selected from at least one of helium, nitrogen, neon, argon, krypton, and xenon. The conditions for the catalytic pyrolysis reaction include: the pyrolysis temperature of the first stage is 20-550℃; the pyrolysis temperature of the second stage is 200-600℃; the pyrolysis time of the first stage and the second stage are each independently 0.00001s-7 years; and the heating rate of the first stage and the second stage are each independently 0-8000℃ / s.

2. The method according to claim 1, wherein, The weight ratio of the metal-based solid acid catalyst to fossil energy is 1:8000-20:

1.

3. The method according to claim 2, wherein, The weight ratio of the metal-based solid acid catalyst to fossil energy is 1:2000-3:

1.

4. The method according to claim 1, wherein, The inert gas is selected from nitrogen.

5. The method according to claim 1, wherein, The conditions for the catalytic pyrolysis reaction include: the pyrolysis temperature of the first stage is 100-500℃; the pyrolysis temperature of the second stage is 250-550℃; the pyrolysis time of the first stage and the second stage are each independently 0.0001s-48h; and the heating rate of the first stage and the second stage are each independently 0-5000℃ / s.

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