Hydrogen fugacity control apparatus and method for hydrocarbon generation thermal simulation

Abstract

The application provides a hydrogen fugacity control device and method for hydrocarbon generation thermal simulation. The hydrogen fugacity control device for hydrocarbon generation thermal simulation comprises an inner tube, a protective tube and an outer tube. The inner tube has a redox buffer accommodating space, and has selective high permeability to hydrogen. The protective tube is sleeved outside the inner tube, and at least one end of the protective tube is not sealed. The outer tube is sleeved outside the protective tube, and the outer tube and the protective tube have a hydrocarbon sample accommodating space to be measured therebetween. The hydrogen fugacity control device and method realize physical and chemical control of hydrogen fugacity, avoid the water fugacity uncertainty problem caused by pressure coupling and material exchange in the traditional method, and ensure the theoretical accuracy and experimental repeatability of the hydrogen fugacity control benchmark.

Description

Technical Field

[0001] This invention relates to the field of hydrocarbon generation thermal simulation technology, and in particular to a hydrogen fugacity control device and method for hydrocarbon generation thermal simulation. Background Technology

[0002] Hydrocarbon generation thermal simulation experiments are a key method for studying the hydrocarbon generation kinetics of source rocks and evaluating oil and gas resource potential. In closed-system thermal simulation experiments, the hydrogen fugacity of the system (… f H2 Hydrogen fugacity is a key environmental parameter affecting the type, rate, and final yield of hydrocarbon generation products from the pyrolysis of organic matter. Precise control of hydrogen fugacity is crucial for simulating real geological conditions and obtaining reliable hydrocarbon generation kinetic parameters.

[0003] Traditional closed-system hydrogenation experiments typically place the hydrogen source (such as hydrogen gas or water) and the sample directly within the same reaction space (such as a steel container or gold tube). As the thermal simulation progresses, the hydrogen source is consumed, and the system's hydrogen fugacity continuously decreases, becoming unstable. This unstable hydrogen fugacity environment prevents researchers from using hydrogen fugacity as a constant control variable to study hydrocarbon behavior, and also makes it impossible to simulate evolutionary processes that closely resemble real geological environments, severely impacting the scientific validity and reproducibility of experimental results.

[0004] CN111024748B discloses a controllable hydrogenation hydrocarbon generation thermal simulation experimental method and apparatus. It uses an internally separated gold tube as a reactor, placing the hydrocarbon generation sample and a redox buffer in two spatially connected but physically isolated chambers. By injecting water and utilizing the chemical equilibrium system formed by the redox buffer and water, it attempts to control the hydrogen fugacity within the closed system of the gold tube. However, the above technical solution has the following drawbacks: 1) Unable to simulate sulfur-containing reaction systems, key gaseous components are absorbed by the buffer: The above technology relies on the exchange of substances and chemical equilibrium between the sample zone and the buffer zone through the aqueous phase. In hydrocarbon generation experiments, the pyrolysis of organic matter may produce sulfur-containing gases such as hydrogen sulfide. After these gases diffuse into the buffer zone, they will react with metal compounds (such as iron and nickel oxides) in the buffer and be absorbed or consumed in large quantities. This makes it impossible for the system to effectively maintain the sulfur-containing reaction environment required for key geological reactions such as thermochemical sulfate reduction (TSR). At the same time, it also seriously interferes with the true composition of gaseous products, making the experimental results unable to reflect the real hydrocarbon generation process in the presence of sulfur-containing organic matter or sulfur-containing fluids.

[0005] 2) Uncontrollable water fugacity leads to inaccurate thermodynamic and kinetic calculations: In the "zonal" device of the above technology, the buffer zone and the sample zone are connected by fluid, causing the aqueous phase to bear the same total pressure applied by the outside as the sample zone, rather than its own thermodynamic equilibrium pressure; more importantly, during the experiment, inorganic salts and some organic matter between the two zones will inevitably cross-diffusion, making the composition, density and fugacity of the aqueous phase in the buffer zone unknown and uncalcifiable, fundamentally shaking the thermodynamic basis for calculating hydrogen fugacity based on this system, resulting in low control accuracy.

[0006] 3) It is essentially a passive control and is susceptible to interference: The above technology relies on the internal multi-component diffusion to achieve chemical equilibrium, which is a "passive" control. Other gases (such as CH4 and CO2) generated by sample pyrolysis may diffuse into the buffer zone, interfering with the balance of the redox buffer pair. At the same time, buffer components may also enter the sample zone in trace amounts. This bidirectional contamination makes the control of hydrogen fugacity not "pure" and stable enough.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a hydrogen fugacity control device and method for simulating hydrocarbon generation heat, which realizes the physicochemical control of hydrogen fugacity, avoids the uncertainty of water fugacity caused by pressure coupling and mass exchange in traditional methods, and ensures the theoretical accuracy and experimental repeatability of the hydrogen fugacity control benchmark.

[0009] This invention provides a hydrogen fugacity control device for simulating hydrocarbon generation heat, comprising an inner tube, a protective tube, and an outer tube. The inner tube has a redox buffer accommodating space and exhibits selective high permeability to hydrogen. The protective tube is fitted over the inner tube, with at least one end of the protective tube unsealed. The outer tube is fitted over the protective tube, and there is a space between the outer tube and the protective tube for accommodating the hydrocarbon generation sample to be tested.

[0010] In this invention, the inner tube can be made of fused silica, which has the characteristic of allowing only H2 molecules to pass freely through its tube wall, while preventing H2O molecules and other larger or different polarity gas molecules (such as CH4, CO2) from passing through.

[0011] Fused silica is a unique microscopic network structure composed of randomly arranged SiO4 tetrahedra. It exhibits a specific "molecular sieve" effect on different gas molecules. Hydrogen permeates through fused silica following a dissolution-diffusion mechanism. The kinetic diameter of a hydrogen molecule is just smaller than the interatomic gaps (free volume) of the fused silica network structure, allowing it to diffuse through as a "molecular sieve" under thermal activation (above 250 °C), while larger molecules (such as N2, Ar, and CO2) are effectively blocked. Gas molecules such as water vapor and carbon dioxide cannot pass freely in molecular form due to their large molecular kinetic diameter and reactive chemical properties. For example, water vapor reacts with the quartz network to form silanol groups (Si-OH), thus disrupting the network structure and incorporating into it, rather than simply permeating as water molecules. Carbon dioxide has a larger kinetic diameter and may weakly react with impurities or defects in the quartz at high temperatures. These chemical interactions fundamentally alter its transport mechanism, preventing it from achieving molecular permeation like hydrogen.

[0012] Furthermore, high-purity fused silica can be used; for example, the hydroxyl content of fused silica can be <10 ppm. If the fused silica contains a large number of hydroxyl groups (-OH), the presence of hydroxyl groups may occupy network space or react with the permeating hydrogen, which not only affects the diffusion path of hydrogen, but also intensifies the reaction with hydrogen at high temperatures, thereby altering the normal permeation behavior of hydrogen.

[0013] In its initial state, the inner tube is open at least one end for adding a redox buffer (or other types of hydrogen-producing minerals) and water. After adding the redox buffer and water, the opening can be sealed using conventional methods, such as rapid sealing with a hydrogen flame welder, to ensure that any residual air is negligible. That is, in its operational state, the inner tube contains a redox buffer and water and is sealed at both ends. The size of the inner tube is not strictly limited and can be set according to actual needs. Specifically, the outer diameter of the inner tube can be 2.8-3.2 mm, the inner diameter can be 2.4-2.6 mm, and the length can be 25-35 mm. The aforementioned inner tube, made of fused silica material with hydrogen permeability meeting experimental requirements, can be obtained commercially available (e.g., products from Polymicro Technologies).

[0014] The protective tube can be made of high-purity, chemically inert materials such as ceramics (e.g., alumina, zirconium oxide). It is fitted over the inner tube and provides mechanical support and thermal protection for the brittle fused silica inner tube, preventing it from crushing under high pressure and buffering thermal stress. At least one end of the protective tube is not sealed to ensure unobstructed hydrogen release. The size of the protective tube is not strictly limited and can be reasonably set according to actual needs; the outer diameter of the protective tube can be 0.5-1 mm larger than the outer diameter of the inner tube.

[0015] The outer tube can be made of pure gold or a gold alloy, possessing good ductility, chemical inertness, and sealing performance, and capable of withstanding high temperature and pressure conditions. As the main reactor and pressure vessel, the outer tube is initially closed at one end and open at the other. The opening is used to add the hydrocarbon sample to be tested, water, and the combination of the inner and protective tubes. After adding the hydrocarbon sample, water, and the combination of the inner and protective tubes, the open end of the outer tube can be flattened using clamps and then tightly sealed using an argon arc welding machine to form a closed system. That is, in the operating state, the outer tube contains the hydrocarbon sample to be tested, water, and the combination of the inner and protective tubes, and both ends are sealed. The dimensions of the outer tube are not strictly limited and can be reasonably set according to actual needs; specifically, the outer diameter of the outer tube can be 5.2-5.6 mm, the inner diameter can be 4.5-5.5 mm, and the length can be 45-55 mm.

[0016] The present invention also provides a method for controlling hydrogen fugacity in hydrocarbon generation heat simulation, which employs the aforementioned hydrogen fugacity control device. The hydrogen fugacity control method includes: S1: Add redox buffer and water to the inner tube and seal it; S2: Place the sealed inner tube inside the protective tube to form a composite; S3: Add the hydrocarbon sample to be tested and water to the outer tube, then place the assembly in the outer tube and seal it; S4: Place the sealed outer tube into the reaction vessel to conduct a hydrocarbon generation thermal simulation test.

[0017] In step S1, the redox buffer is at least one of cobalt-cobalt monoxide buffer, nickel-nickel oxide buffer, and magnetite-hematite buffer; the ratio of redox buffer to water is 8-12 mg: 8-12 μL.

[0018] In step S3, the ratio of the hydrocarbon sample to water is 25-35 mg: 90-110 μL.

[0019] In step S4, the temperature during the hydrocarbon generation thermal simulation test is 300-650 ℃, the pressure is 300-500 bar, and the time is 60-80 h.

[0020] The target hydrogen fugacity is obtained using the following formula:

[0021] in: f H2 For the target hydrogen fugacity, K w The equilibrium constant for the water dissociation reaction is denoted as . f H2O For water fugacity, fO2 Oxygen fugacity is obtained using the following formula:

[0022] in: a , b , c These are the thermodynamic parameters of redox buffers. P inner For pressure, T For temperature.

[0023] Compared with the prior art, the present invention has at least the following advantages: 1) High control precision and high purity: By utilizing the selective permeability of hydrogen gas through the inner tube, the physicochemical control of hydrogen fugacity is achieved, which fundamentally avoids cross-contamination or reaction consumption of gas molecules between the sample area and the buffer area, ensuring that the water fugacity in the buffer area can be accurately calculated. The control precision and purity are far higher than those of the traditional chemical equilibrium method. This effect is particularly significant in sulfur-containing reaction systems.

[0024] 2) Thermodynamic state is well-defined and can be precisely designed: Since the inner tube is a constant volume system, its internal pressure, water fugacity and other key parameters are determined only by the initial mass of the loaded material (water density) and the experimental temperature. It can be accurately calculated and designed through thermodynamic models, which fundamentally avoids the uncertainty of water fugacity caused by pressure coupling and mass exchange in traditional methods, and ensures the theoretical accuracy and experimental repeatability of hydrogen fugacity control benchmark.

[0025] 3) Good stability and reliability: The redox buffer system inside the inner tube is sealed in an independent tube body, which is not affected by the external environment. It can provide an extremely stable target hydrogen fugacity reference value and continuously maintain the constant external hydrogen fugacity through the reversible permeation of hydrogen.

[0026] 4) Wide applicability: The device has the advantages of traditional gold tube system such as high temperature and high pressure resistance, and can be applied to the entire temperature and pressure range of hydrocarbon generation simulation (such as 300-650 ℃, tens to hundreds of MPa), expanding the application boundaries of precision hydrogen fugacity control technology.

[0027] 5) Simple structure and easy to implement: The device has a clever structural design, with clear functions for each component. The preparation and sample loading process can be well integrated with the existing gold tube experimental process, making it easy to promote and use. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the hydrogen fugacity control device of the present invention.

[0030] Explanation of reference numerals in the attached figures: 1: Inner tube; 2: Protective tube; 3: Outer tube. Detailed Implementation

[0031] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0032] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1 Combination Figure 1 As shown, the hydrogen fugacity control device for simulating hydrocarbon generation heat in this embodiment includes an inner tube 1, a protective tube 2, and an outer tube 3. The inner tube 1 has a redox buffer accommodating space and has selective high permeability to hydrogen. The protective tube 2 is sleeved outside the inner tube 1, and at least one end of the protective tube 2 is not sealed. The outer tube 3 is sleeved outside the protective tube 2, and there is a space for accommodating the hydrocarbon generation sample to be tested between the outer tube 3 and the protective tube 2.

[0035] The inner tube 1 can be made of fused silica, which allows only H2 molecules to pass freely through its wall while preventing H2O molecules and other larger or differently polar gas molecules (such as CH4 and CO2) from passing through. High-purity fused silica can be used, with a hydroxyl content of <10 ppm.

[0036] The inner tube 1 has a space for holding a redox buffer (such as a mineral buffer) and water (such as deionized water). In the initial state, the inner tube 1 is open at at least one end for adding the redox buffer and water. After adding the redox buffer and water, the opening can be sealed using conventional methods, such as rapid sealing with a hydrogen flame welder, to ensure that any residual air is negligible. In the usage state, the inner tube 1 is filled with the redox buffer and water and is sealed at both ends. The dimensions of the inner tube 1 are not strictly limited and can be reasonably set according to actual needs; specifically, the outer diameter of the inner tube 1 can be 2.8-3.2 mm, the inner diameter can be 2.4-2.6 mm, and the length can be 25-35 mm.

[0037] It is understandable that inner tube 1 is a constant-volume system, and its key parameters such as internal pressure and water fugacity are determined only by the initial mass of the substance (water density) and the experimental temperature. This allows for precise and forward-looking calculations and design using thermodynamic models, fundamentally avoiding the uncertainty in water fugacity caused by pressure coupling and mass exchange in traditional methods. This ensures the theoretical accuracy and experimental repeatability of the hydrogen fugacity control benchmark. Furthermore, the redox buffer system inside inner tube 1 is sealed within an independent tube, unaffected by external environmental interference. It provides an extremely stable target hydrogen fugacity reference value and continuously maintains a constant external hydrogen fugacity through reversible hydrogen permeation, exhibiting high stability and reliability.

[0038] The protective tube 2 can be made of high-purity, chemically inert materials such as ceramics (e.g., alumina, zirconium oxide). The protective tube 2 is fitted over the inner tube 1, providing mechanical support and thermal protection for the brittle fused silica inner tube 1, preventing it from collapsing under high pressure and buffering thermal stress. At least one end of the protective tube 2 is not sealed to ensure unobstructed hydrogen release. The dimensions of the protective tube 2 are not strictly limited and can be reasonably set according to actual needs; the outer diameter of the protective tube 2 can be 0.5-1 mm larger than the outer diameter of the inner tube 1.

[0039] The outer tube 3 can be made of pure gold or a gold alloy, possessing good ductility, chemical inertness, and sealing performance, and capable of withstanding high temperature and pressure conditions. As the main reactor and pressure vessel, the outer tube 3 is initially closed at one end and open at the other. The opening is used to add the hydrocarbon generation sample to be tested, water, and the combination of the inner tube 1 and the protective tube 2. After adding the hydrocarbon generation sample (i.e., the hydrocarbon source sample), water, and the combination of the inner tube 1 and the protective tube 2, the open end of the outer tube 3 can be flattened using clamps and then tightly sealed using an argon arc welding machine to form a closed system. In the operating state, the outer tube 3 contains the hydrocarbon generation sample to be tested, water, and the combination of the inner tube 1 and the protective tube 2, and both ends are sealed. The dimensions of the outer tube 3 are not strictly limited and can be reasonably set according to actual needs; specifically, the outer diameter of the outer tube 3 can be 5.2-5.6 mm, the inner diameter can be 4.5-5.5 mm, and the length can be 45-55 mm.

[0040] The hydrogen fugacity control device in this embodiment has a simple structure and is applicable to the entire temperature and pressure range of hydrocarbon generation simulation. By utilizing the selective permeability of hydrogen gas through the inner tube 1, the physicochemical control of hydrogen fugacity is achieved, which fundamentally avoids cross-contamination or reaction consumption of gas molecules between the sample area and the buffer area, ensuring that the water fugacity in the buffer area can be accurately calculated. The control precision and purity are far higher than those of the traditional chemical equilibrium method.

[0041] Example 2 The hydrogen fugacity control method for hydrocarbon generation heat simulation in this embodiment uses the hydrogen fugacity control device from Example 1, and the steps are as follows: S1: Add buffer First, add redox buffer and water to the open end of inner tube 1. The redox buffer can be cobalt-cobalt monoxide buffer, nickel-nickel oxide buffer, magnetite-hematite buffer, etc. The ratio of redox buffer to water can be 8-12 mg: 8-12 μL. Then, select a suitable position on one side of the open end of inner tube 1 and use a hydrogen flame welder to quickly seal it to ensure that the residual air is negligible.

[0042] S2: Combination of inner tube and protective tube The sealed inner tube 1 is placed inside the protective tube 2 to form an assembly.

[0043] S3: Sample Preparation Add the hydrocarbon sample to be tested and water to the outer tube 3. The ratio of the hydrocarbon sample to water can be 25-35 mg: 90-110 μL. Then, place the combination of the inner tube 1 and the protective tube 2 into the outer tube 3, use clamps to flatten the open end of the gold tube, and seal it tightly with an argon arc welding machine to form a closed system.

[0044] S4: Hydrogen generation thermal simulation test The sealed system formed by the above sealing is placed in a reaction vessel to conduct a hydrocarbon generation thermal simulation test. The conditions of the hydrocarbon generation thermal simulation test can be determined according to actual needs; specifically, the temperature of the hydrocarbon generation thermal simulation test can be 300-650 ℃, the pressure can be 300-500 bar, and the time can be 60-80 h.

[0045] The working and control principles of the above-mentioned device and method are as follows: After the assembled device is sealed, it is placed in a high-temperature and high-pressure reactor.

[0046] At the experimental temperature, the water in inner tube 1 reacts with the redox buffer, generating and maintaining a stable and precise internal hydrogen fugacity determined by this buffer pair. f H2 High-purity fused silica has a much higher hydrogen permeability than traditional precious metal hydrogen membranes. It can diffuse to equilibrium at temperatures above 300 °C for several hours, and exhibits extremely low permeability to molecules such as H₂O and CO₂. This makes it possible to independently and precisely control the hydrogen fugacity in the external sample area through selective hydrogen permeation. Based on the high permeability of hydrogen in fused silica, hydrogen molecules diffuse from the side with higher chemical potential through the tube wall to the side with lower chemical potential until the chemical potential (i.e., hydrogen fugacity) of hydrogen inside and outside the tube reaches equality. At this point, the hydrogen fugacity in the external sample area (… f H2-external That is, it is precisely locked to the internal reference ( f H2-internal The level is consistent with that of "osmotic equilibrium" ( f H2-external ≈ f H2-internal Therefore, regardless of the hydrocarbon generation reaction occurring in the external sample area or the type of gas produced, the external hydrogen fugacity ( f H2 All of them will be forcibly and precisely stabilized at the target value set by the internal redox buffer, and will not be disturbed by the composition of external gases, thus achieving "active" and "pure" control of the hydrogen fugacity in the sample area.

[0047] Furthermore, after sealing, inner tube 1 constitutes a constant-volume, closed thermodynamic system, in which the amounts of redox buffer and deionized water are precisely known. Under these conditions, the water fugacity (…) f H2O The oxygen fugacity can be accurately calculated using the equation of state for water; combined with the thermodynamic data of the redox buffer used, the oxygen fugacity can be calculated, and then, based on the dissociation equilibrium of water, the target hydrogen fugacity maintained by the inner tube 1 system can be accurately and quantitatively calculated. f H2This target value does not change with the reaction of external samples, and the hydrogen fugacity in the sample area is stably and precisely controlled through the selective permeation of hydrogen.

[0048] Example 3 This embodiment is a specific example of Embodiment 1, as detailed below: 1. Equipment preparation A gold tube with an outer diameter of 5.4 mm, an inner diameter of 5.0 mm, and a length of approximately 50 mm was selected as the outer tube 3.

[0049] A high-purity fused silica tube with an outer diameter of 3.0 mm, an inner diameter of 2.5 mm, and a length of approximately 30 mm was selected as inner tube 1, and one end of it was sealed by melting with a high-temperature flame.

[0050] Add approximately 10 mg of MH (magnetite-hematite) buffer (magnetite to hematite mass ratio of 2:1) and 10 μL of deionized water to the other end of the inner tube 1. Then, select a suitable position on one side of the opening end of the inner tube 1 and quickly seal it with a hydrogen flame welder to ensure that the air residue is negligible.

[0051] Carefully insert the sealed inner tube 1 into a protective tube 2 (outer diameter 3.8 mm) made of alumina ceramic to form a combination of inner tube 1 and protective tube 2.

[0052] 2. Sample preparation Weigh approximately 30 mg of the kerogen powder sample to be tested and place it in the outer tube 3; inject approximately 100 μL of deionized water into the outer tube 3, and then place the combination of the inner tube 1 and the protective tube 2 into the outer tube 3.

[0053] Use pliers to flatten the open end of the outer tube 3, and then use an argon arc welding machine to tightly seal it, forming a closed system.

[0054] 3. Experiment The sealed system was placed into the reactor of the thermal simulation experimental device. The experimental conditions were set as follows: pressure 400 bar, rapid heating from room temperature to 400 °C, and constant temperature for 72 h.

[0055] After the experiment, it was found that the redox buffer in inner tube 1 turned significantly reddish-brown, verifying that the independent buffer system in inner tube 1 was operating as designed and had the source conditions to provide a stable hydrogen fugacity benchmark for the outside. In addition, chromatographic analysis of the gaseous products collected from the external sample area revealed an H2 content higher than the background value.

[0056] 4. Theoretical calculation of control targets After being sealed, inner tube 1 constitutes an independent constant-volume thermodynamic system, based on its known geometric volume V and the precise amount of water filled m. H2OThe initial water density ρ = m can be determined. H2O / V.

[0057] Under the conditions of this embodiment (constant temperature 400 °C), the system is in the supercritical state of water, and its evolution path is uniquely determined by the initial density ρ. According to the IAPWS-95 equation of state published by the International Association for the Properties of Water and Vapor, the internal pressure P of the isotropic system when it reaches thermal equilibrium can be accurately calculated by inputting (T = 400 °C, ρ). inner and water fugacity f H2O .

[0058] Meanwhile, the MH (magnetite-hematite) buffer used in inner tube 1 operates at a given temperature T and pressure P. inner Below, its oxygen fugacity f O2 It can be determined by the following empirical formula:

[0059] in: a , b , c The thermodynamic parameters of redox buffers (MH buffers) can be obtained from standard thermodynamic data sheets or relevant literature in this field. P inner For pressure, T For temperature Finally, based on the equilibrium constant of the water dissociation reaction... K w The target hydrogen fugacity preset in the device of this embodiment is accurately calculated using (T) and the following thermodynamic relationship. f H2 :

[0060] in: f H2 For the target hydrogen fugacity, K w The equilibrium constant for the water dissociation reaction is denoted as . f H2O For water fugacity, f O2 This refers to oxygen fugacity.

[0061] The above calculations show that by precisely designing the initial filling conditions of the inner tube 1 (water volume, type of buffer), the stable hydrogen fugacity control value that the device will provide to the external sample area can be accurately set and calculated. Hydrogen molecules selectively permeate through the inner tube wall made of fused silica material, thus controlling the hydrogen fugacity in the external sample area. f H2 (external) Approaching and stabilizing at the target value fH2 (target) .

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydrogen fugacity control device for simulating hydrocarbon generation heat, characterized in that, It includes an inner tube, a protective tube, and an outer tube. The inner tube has a space for accommodating a redox buffer and has a selective high permeability to hydrogen. The protective tube is fitted outside the inner tube and is not sealed at least at one end. The outer tube is fitted outside the protective tube and has a space between the outer tube and the protective tube for accommodating the hydrocarbon sample to be tested.

2. The hydrogen fugacity control device according to claim 1, characterized in that, The inner tube is made of fused silica.

3. The hydrogen fugacity control device according to claim 1, characterized in that, The protective tube is made of ceramic.

4. The hydrogen fugacity control device according to claim 1, characterized in that, The outer tube is made of pure gold or a gold alloy.

5. A method for controlling hydrogen fugacity in hydrocarbon generation thermal simulation, characterized in that, The hydrogen fugacity control device according to any one of claims 1-4 is used, and the hydrogen fugacity control method includes: S1: Add redox buffer and water to the inner tube and seal it; S2: Place the sealed inner tube inside the protective tube to form a composite; S3: Add the hydrocarbon sample to be tested and water to the outer tube, then place the assembly in the outer tube and seal it; S4: Place the sealed outer tube into the reaction vessel to conduct a hydrocarbon generation thermal simulation test.

6. The hydrogen fugacity control method according to claim 5, characterized in that, In step S1, the redox buffer is at least one of cobalt-cobalt monoxide buffer, nickel-nickel oxide buffer, and magnetite-hematite buffer.

7. The hydrogen fugacity control method according to claim 5, characterized in that, In step S1, the ratio of redox buffer to water is 8-12 mg: 8-12 μL.

8. The hydrogen fugacity control method according to claim 5, characterized in that, In step S3, the ratio of the hydrocarbon sample to water is 25-35 mg: 90-110 μL.

9. The hydrogen fugacity control method according to claim 5, characterized in that, In step S4, the temperature during the hydrocarbon generation thermal simulation test is 300-650 ℃, the pressure is 300-500 bar, and the time is 60-80 h.

10. The hydrogen fugacity control method according to claim 5, characterized in that, The target hydrogen fugacity is obtained using the following formula: in: f H2 For the target hydrogen fugacity, K w The equilibrium constant for the water dissociation reaction is denoted as . f H2O For water fugacity, f O2 Oxygen fugacity is obtained using the following formula: in: a , b , c These are the thermodynamic parameters of redox buffers. P inner For pressure, T For temperature.

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