Oil shale-assisted water electrolysis hydrogen production system

Abstract

This invention provides a shale-assisted water electrolysis hydrogen production system, belonging to the field of hydrogen energy production and resource comprehensive utilization technology. The invention includes an oil shale pretreatment and feeding device, a sulfuric acid storage tank, a primary reactor, an oil shale washing device, a secondary reactor, an electrolysis hydrogen production device, a by-product collection device, a hydrogen storage tank, and a carbon dioxide storage tank, all connected sequentially via pipelines. By introducing oil shale into the electrolysis process, this invention not only effectively reduces the energy consumption of water electrolysis and improves hydrogen production efficiency, but also achieves the synergistic conversion of organic matter and inorganic minerals in oil shale, obtaining various valuable products such as hydrogen, silicon dioxide, and calcium sulfate, thus achieving the dual goals of clean energy production and green solid waste treatment.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy production and comprehensive resource utilization technology, specifically to an oil shale-assisted water electrolysis hydrogen production system, which is applicable to new energy hydrogen production, clean utilization of oil shale, and solid waste treatment, and can be widely used in the energy, petrochemical, and environmental protection industries. Background Technology

[0002] Currently, the mainstream hydrogen production technologies in the market mainly include natural gas steam reforming, coal gasification, and water electrolysis. Among them, water electrolysis is considered an important future direction for clean hydrogen production due to its high product purity, relatively simple process, and ability to be coupled with renewable energy. However, existing water electrolysis technologies generally rely on precious metal catalysts and high-purity electrolytes, resulting in problems such as high equipment investment, high operating costs, significant energy consumption, and excessive dependence on electricity supply. Meanwhile, the development and utilization of unconventional energy resources such as oil shale are mainly concentrated in areas such as dry distillation for oil production, direct combustion for power generation, or as chemical raw materials, which generally suffer from high energy consumption, heavy pollution, and difficulty in treating by-products.

[0003] Existing defects:

[0004] (1) In the field of hydrogen production by water electrolysis: the energy consumption level is relatively high, the electrolysis efficiency is limited, and the operating cost remains high, which restricts the large-scale application and promotion; some systems need to rely on precious metal electrodes or high-purity chemical reagents, which is not economically viable.

[0005] (2) Oil shale utilization: Traditional dry distillation processes have low oil yields, complex by-product compositions, and difficulties in treating oily sludge and semi-coke, resulting in significant environmental pressure; the existing technology system has failed to effectively achieve the synergistic integration and utilization of oil shale resources and hydrogen production technology.

[0006] (3) Lack of synergy: The current hydrogen production technology and oil shale processing technology are basically disconnected, failing to take into account the dual goals of clean hydrogen production and green disposal of solid waste. Summary of the Invention

[0007] In view of this, in order to solve the technical problems of high energy consumption and poor economic efficiency in existing water electrolysis hydrogen production, as well as high energy consumption, heavy pollution, and difficult by-product treatment in the utilization of oil shale, this invention provides a system for oil shale-assisted water electrolysis hydrogen production. By introducing oil shale into the electrolysis process, this invention can not only effectively reduce the energy consumption of water electrolysis and improve hydrogen production efficiency, but also realize the synergistic transformation of organic matter and inorganic minerals in oil shale to obtain a variety of valuable products such as hydrogen, silicon dioxide, and calcium sulfate, thus achieving the dual goals of clean energy production and green solid waste treatment.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] An oil shale-assisted water electrolysis hydrogen production system includes an oil shale pretreatment and feeding device, a sulfuric acid storage tank, a primary reactor, an oil shale washing device, a secondary reactor, an electrolysis hydrogen production device, a by-product collection device, a hydrogen storage tank, and a carbon dioxide storage tank, with each device connected in sequence via pipelines.

[0010] The outlet of the pretreatment and feeding device is connected to the inlet of the primary reactor and is used to transport oil shale particles.

[0011] The sulfuric acid storage tank is connected to the acid inlet of both the primary reactor and the secondary reactor.

[0012] The solid residue outlet of the primary reactor is connected to the oil shale washing device, the reaction liquid outlet is connected to the secondary reactor, and the gas outlet is connected to the carbon dioxide storage tank.

[0013] The discharge port of the oil shale washing device is connected to the residue inlet of the secondary reactor;

[0014] The reaction liquid outlet of the secondary reactor is connected to the anode chamber of the electrolytic hydrogen production device, and the solid residue outlet is connected to the by-product collection device.

[0015] The cathode chamber gas outlet of the electrolytic hydrogen production device is connected to the hydrogen storage tank, and the anode chamber waste liquid outlet is connected to the sulfuric acid storage tank through a return pipeline.

[0016] Preferably, the oil shale cleaning device includes a circulating fluid flushing unit and an organic solvent cleaning unit.

[0017] Preferably, the organic solvent in the organic solvent cleaning unit is acetone or dichloromethane.

[0018] Preferably, the electrolytic hydrogen production device further includes a proton exchange membrane, and the anode and cathode electrodes are platinum sheet electrodes, wherein the anode chamber is lined with Fe. 2+ / Fe 3+ Redox system.

[0019] Preferably, the primary reactor and the secondary reactor are connected in series, the temperature of the primary reactor is 60℃±10℃, and the temperature of the secondary reactor is 10℃ higher than that of the primary reactor.

[0020] Preferably, the by-product collection device includes a solid-liquid separation unit and a drying unit for recovering silica and calcium sulfate solid by-products.

[0021] Preferably, the sulfuric acid storage tank has a built-in PID concentration control system, which controls the feed rate in conjunction with the acid supply to the primary reactor, and maintains the concentration of dilute sulfuric acid at 40% ± 2% through the PID concentration control system.

[0022] Preferably, the electrolysis voltage of the electrolytic hydrogen production device is 1.1V±0.1V, and the current density is 10mA / cm²±2mA / cm².

[0023] Preferably, the particle size of the oil shale particles is 0.5-2 mm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) Modular collaborative design to achieve deep coupling of oil shale and water electrolysis.

[0026] This invention comprises a complete process module consisting of pretreatment, reaction, electrolysis, and recovery, with each unit having a clearly defined function and working in close coordination. The pretreatment and feeding unit crushes the oil shale to a particle size of 0.5-2 mm to ensure maximum contact area for reaction with sulfuric acid. The primary reactor and secondary reactor are connected in series; the former performs mineral acid hydrolysis, releasing… Dissolve The latter is achieved through the reduction of organic matter from oil shale. for ,form / The circulating system provides an "electron buffer" for electrolysis. The electrolytic hydrogen production unit is directly connected to the reaction system, utilizing the circulating system. / By replacing the oxygen reaction, the electrolysis voltage is reduced to 1.0~1.1V, while the theoretical minimum voltage for traditional water electrolysis is 1.23V, and the actual engineering application voltage for traditional water electrolysis is generally 1.8-2.0V. This reduces energy consumption by approximately 39~50%. (1.1-1.8) / 1.8 = -0.388889 ≈ 39%, (1.0-2.0) / 2.0 = 50%. Therefore, energy consumption is reduced by approximately 39~50%.

[0027] (2) Utilization of all components of oil shale, significantly improving resource conversion rate.

[0028] Mineral resource recovery: Through acid hydrolysis in a primary reactor and solid-liquid separation in a by-product collection device, inorganic minerals such as Ca and Si in oil shale are converted into calcium sulfate and silicon dioxide, realizing the resource utilization of solid waste, with a by-product recovery rate of ≥90%.

[0029] Organic matter energy conversion: Residual organic carbon in oil shale acts as a reducing agent in a secondary reactor, transforming... Restore to It replaces 30% of electricity consumption, achieving "energy supplementation from waste".

[0030] (3) Low-energy electrolysis mechanism, breaking through the energy efficiency bottleneck of traditional water electrolysis.

[0031] Iron ion recycling replaces oxygen evolution reaction: in the anode chamber of an electrolytic hydrogen production unit, Oxidized to Compared with the oxygen evolution reaction of traditional water electrolysis (the theoretical minimum voltage is 1.23V), it reduces the anode overpotential and significantly reduces the overall electrolysis energy consumption.

[0032] High-efficiency mass transfer via proton exchange membrane: Built-in proton exchange membrane for directional transport. The proton exchange membrane only allows By preventing the gas (such as trace amounts of unreacted gas) from entering the anode chamber. (Or volatile organic compounds) enter the cathode chamber, physically preventing gas mixing and cross-contamination. Since no other side reactions occur in the cathode chamber, the cathode product is only H2, achieving a hydrogen purity of 99.99%, requiring no additional purification. Currently, PEM (Polymerized Electrolyte) technology produces hydrogen with a purity greater than 99.99%. AEM (Alternating Electrolyte) typically achieves 99.9% purity (with trace amounts of...). Enter (Side). The electrolysis section of this invention is also at room temperature, with negligible water vapor, achieving the hydrogen purity of PEM technology.

[0033] (4) Near-zero emissions of pollutants, with outstanding environmental friendliness.

[0034] Targeted CO2 recovery: CO2 produced by the primary reactor Collected in carbon dioxide storage tanks, the product is formed due to the reaction of carbonates and sulfuric acid. ↓、 ↑ and , Almost all of it is recycled into storage tanks, with a recovery rate of ≥95%, and can be used for resource utilization such as methanol synthesis and carbonated beverages, avoiding direct emissions. Currently, industrial-scale carbon capture technology... Recovery rates typically reach 85%–95%, and can be further improved to over 95% through process optimization. Some systems (such as oxy-fuel combustion or enhanced absorption systems) can approach 98%–99%. This is all under complex atmospheric conditions. Recycling. However, this invention only involves the chemical reaction between carbonates and sulfuric acid, producing... Gases, which are very easy to achieve 95% purity. Recycle.

[0035] Waste liquid closed-loop recycling: The sulfuric acid storage tank receives the anode waste liquid from the electrolysis unit, and after concentration adjustment, it is reused for the reaction. That is, the acid liquid of the present invention has a closed-loop process from "reaction-electrolysis-regeneration-re-reaction". Combined with precise concentration control and multi-stage reaction synergy, considering a loss of about 10%, the utilization rate of acid liquid is finally increased to about 90%, reducing wastewater discharge.

[0036] Complete solid waste treatment: After the oil shale is reacted, all the residue is converted into useful by-products such as calcium sulfate and silicon dioxide, without generating secondary solid waste.

[0037] In summary, the process of hydrogen production by electrolysis of water is optimized by utilizing the organic matter and mineral components in oil shale: after crushing and screening, the oil shale undergoes an acidolysis reaction with sulfuric acid in a primary reactor, releasing... And dissolve Metal ions and residues, after washing, enter a secondary reactor, where organic matter will... Restore to ,form / The recycling system replaces some of the oxygen-generating reactions in the electrolytic hydrogen production unit, while simultaneously recovering solid products such as silica and calcium sulfate through a byproduct collection device, achieving "low-energy hydrogen production + oil shale resource utilization +..." The triple goal of "emission reduction (recycling rate ≥95%)" has both economic and environmental value. Attached Figure Description

[0038] Figure 1 This is an overall layout diagram of the present invention;

[0039] In the diagram, 1 is a sulfuric acid storage tank; 2 is a primary reactor; 3 is a secondary reactor; 4 is an electrolytic hydrogen production unit; 5 is a by-product collection unit; and 6 is a hydrogen storage tank. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] like Figure 1 As shown, the present invention provides an oil shale-assisted electrolysis water hydrogen production system, including an oil shale pretreatment and feeding device, a sulfuric acid storage tank 1, a primary reactor 2, an oil shale washing device, a secondary reactor 3, an electrolysis hydrogen production device 4, a by-product collection device 5, a hydrogen storage tank 6, and a carbon dioxide storage tank, with each device connected in sequence via pipelines.

[0044] The oil shale pretreatment and feeding device preferably includes a jaw crusher, a vibrating screen, and a screw conveyor. These components crush and screen the oil shale to a suitable particle size and quantitatively feed it to the reaction system, ensuring feed stability, uniform oil shale particle size, and increasing the contact area for subsequent reactions. The preferred particle size of the oil shale is 0.5-2 mm. The feed rate is linked to the acid supply in the primary reactor 2. For example, the PID concentration control system built into the sulfuric acid storage tank 1 automatically adjusts the dilute sulfuric acid concentration based on the feed rate. When the concentration is high, water is added to maintain the dilute sulfuric acid concentration at 40% ± 2% to ensure the smooth progress of the reaction.

[0045] Sulfuric acid storage tank 1, preferably a corrosion-resistant stainless steel tank lined with polytetrafluoroethylene (PTFE) coating, is used to store and supply dilute sulfuric acid electrolyte required for electrolysis. Preferably, sulfuric acid storage tank 1 has a built-in PID concentration control system to maintain the dilute sulfuric acid concentration at 40%±2%. Specifically, it has a built-in stirrer and concentration sensor, stores 40%±2% dilute sulfuric acid electrolyte, and supplies the electrolyte to the reactor through a metering pump to maintain the acidic environment of the reaction system.

[0046] Reactor 2, preferably a corrosion-resistant, closed reactor, is specifically made of titanium alloy with a polytetrafluoroethylene (PTFE) coating, and includes a heating jacket, a stirring paddle, and a gas outlet. Here, oil shale undergoes a preliminary reaction with sulfuric acid, releasing soluble organic matter and some mineral components. Carbonates are converted to sulfates and released... Metal oxides (such as Dissolve, generate Multiple ions in various valence states enter the reaction solution.

[0047] The oil shale cleaning device preferably has a double-layer cleaning tank, with the upper layer being a circulating liquid rinsing unit and the lower layer being an organic solvent cleaning unit. The organic solvent is preferably acetone or dichloromethane. It is equipped with an ultrasonic auxiliary device to clean the oil shale residue after the first reaction, remove surface impurities, and improve the efficiency of the secondary reaction.

[0048] Secondary reactor 3, preferably a continuous stirred reactor, is connected to sulfuric acid storage tank 1 to replenish fresh acid. Here, the cleaned oil shale and reaction liquid are further processed to promote deep conversion and generate hydrogen and byproducts. The organic matter in the oil shale residue will... Restore to Maintain electrolyte concentration / The primary reactor 2 and the secondary reactor 3 are preferably connected in series. The temperature of the primary reactor 2 is 60℃±10℃, and the temperature of the secondary reactor 3 is 10℃ higher than that of the primary reactor 2.

[0049] The electrolytic hydrogen production unit 4 includes an anode chamber, a cathode chamber, and a proton exchange membrane. It is powered by an external DC power supply with an electrolysis voltage of 1.1V ± 0.1V and a current density of 10mA / cm² ± 2mA / cm². Anode: Internal. / Redox systems Losing electrons and oxidizing to Reduce the electrolysis voltage to a minimum of 1.0V; Cathode: hydrogen evolution reaction, Generate electrons .

[0050] The by-product collection device 5 includes a solid-liquid separation unit and a drying unit, used to recover solid by-products such as silica and calcium sulfate. Preferably, it is a plate and frame filter press combined with a vacuum drying oven to separate reaction residues. This is used to separate and collect solid by-products such as silica and calcium sulfate from the residues for use as building materials or chemical raw materials, thus achieving resource utilization.

[0051] Hydrogen storage tank 6: Used to collect and store hydrogen produced by electrolysis, facilitating subsequent compression, transportation or direct use.

[0052] Carbon dioxide storage tanks are used to collect the carbon dioxide produced during the reaction process. This avoids emissions and allows for subsequent resource utilization.

[0053] The outlet of the pretreatment and feeding device is connected to the inlet of the primary reactor 2 and is used to transport oil shale particles.

[0054] The sulfuric acid storage tank 1 is connected to the acid inlet of both the primary reactor 2 and the secondary reactor 3.

[0055] The solid residue outlet of the primary reactor 2 is connected to the oil shale washing device, the reaction liquid outlet is connected to the secondary reactor 3, and the gas outlet is connected to the carbon dioxide storage tank.

[0056] The discharge port of the oil shale washing device is connected to the residue inlet of the secondary reactor 3;

[0057] The reaction liquid outlet of the secondary reactor 3 is connected to the anode chamber of the electrolytic hydrogen production device 4, and the solid residue outlet is connected to the by-product collection device 5.

[0058] The cathode chamber gas outlet of the electrolytic hydrogen production device 4 is connected to the hydrogen storage tank 6, and the anode chamber waste liquid outlet is connected to the sulfuric acid storage tank 1 through a return pipeline.

[0059] The connection relationships of the nine modules in the oil shale-assisted water electrolysis hydrogen production system of the present invention are as follows:

[0060] The oil shale pretreatment and feeding device is connected to the inlet of the primary reactor 2 via a conveying pipeline, used to continuously or intermittently feed the crushed oil shale particles into the reaction system. The sulfuric acid storage tank 1 is connected to the primary reactor 2 via a corrosion-resistant conveying pipe, providing the required dilute sulfuric acid solution to the reaction system; valves are installed on the pipeline to control the flow rate and concentration. The outlet of the primary reactor 2 is connected to the oil shale washing device on one hand to wash the solid residue after the reaction; on the other hand, it is connected to the carbon dioxide storage tank. The outlet of the oil shale washing device is connected to the secondary reactor 3, allowing the washed oil shale residue to enter the next reaction step, avoiding acid accumulation that could affect reaction efficiency. The secondary reactor 3 is interconnected with the electrolytic hydrogen production device 4, and also connected to the carbon dioxide storage tank and the sulfuric acid storage tank 1. The gas outlet of the electrolytic hydrogen production device 4 is connected to the hydrogen storage tank 6 via pipelines to achieve gas separation and collection. The outlet of the by-product collection device 5 is equipped with a solid-liquid separation unit; the solid product is recycled, and the liquid portion can be recycled back to the sulfuric acid storage tank 1 or discharged.

[0061] The working principle of the oil shale-assisted water electrolysis hydrogen production system provided by this invention is as follows:

[0062] Feed and acid supply

[0063] The oil shale pretreatment and feeding device continuously or intermittently transports oil shale particles crushed to a diameter of 2mm to the primary reactor 2; the sulfuric acid storage tank 1 sprays a 40% dilute sulfuric acid solution into the primary reactor 2 through a conveying pipeline, and the oil shale and acid solution react in contact under closed conditions.

[0064] Primary reaction stage

[0065] In reactor 2, sulfuric acid first reacts with carbonate minerals in the oil shale via acidolysis. The generated carbon dioxide is directly transported to a carbon dioxide storage tank for collection. Subsequently, the sulfuric acid continues to act on the mineral framework of the oil shale, dissolving metal cations (such as multivalent ions like Fe) and allowing them to enter the reaction solution. Furthermore, the residual organic carbonaceous matter in the oil shale exhibits strong reducing properties under acidic conditions, which can reduce the anolyte generated in the reaction solution. Restored to , forming a local / The recycling system not only improves the reusability of iron ions but also indirectly reduces the potential required for electrolysis anodes, thereby further reducing energy consumption. The partially dissolved sulfuric acid solution is introduced into the anode region of the electrolytic hydrogen production unit 4 through pipelines, participating in the electrolysis reaction and improving the conductivity of the electrolyte. After the above reaction, the remaining oil shale solids and reaction liquid are discharged from the primary reactor 2. The solid portion is transported to the oil shale washing device, while the liquid portion can flow directly into the secondary reactor 3 or the sulfuric acid storage tank 1 for further decomposition and conversion.

[0066] Oil shale washing stage

[0067] In the oil shale cleaning device, the oil shale residue after reaction is first rinsed with circulating liquid to remove residual sulfuric acid and some soluble impurities from the surface. During the experiment, it was found that insoluble impurities and organic residues often adhere to the surface of oil shale, and rinsing with water or dilute acid alone is insufficient for thorough removal. Therefore, this device further introduces an organic solvent (acetone, dichloromethane, etc.) cleaning step. Through the dissolving effect of the organic solvent, organic impurities on the surface of the oil shale particles can be effectively removed, significantly improving the cleanliness of the residue surface. Here, the oil shale can be further crushed from 2mm to 0.5mm. The surface of the cleaned solid particles is more conducive to full contact with the reaction liquid, thereby improving the conversion rate and stability of the reaction after entering the secondary reactor 3.

[0068] Secondary reaction stage

[0069] The cleaned oil shale residue, along with the reaction liquid from the primary reactor 2, enters the secondary reactor 3, where further deep decomposition and conversion reactions continue. Simultaneously, the secondary reactor 3 is connected to the sulfuric acid storage tank 1, and some newly added dilute sulfuric acid is introduced into this unit to maintain the acidic environment and ionic strength of the reaction liquid. During this stage, the unreacted carbonaceous components in the residue continue to exert a reducing effect, partially reducing the shale residue accumulated during electrolysis. Restore to This maintains a high concentration of ferrous ions in the system. This reduction cycle mechanism helps enhance the electronic buffering capacity of the reaction solution, stabilize the electrolysis process, and increase the hydrogen yield. The liquid product formed after the secondary reaction flows into the electrolytic hydrogen production unit 4, participates in the electrolysis process in the anode region, and further promotes hydrogen generation. Excess acid that is not completely consumed during the electrolysis process is returned to the sulfuric acid storage tank 1 through a circulation pipeline, realizing the regeneration and recycling of the electrolyte.

[0070] Electrolysis stage

[0071] In the electrolytic hydrogen production unit 4, the device consists of a cathode chamber and an anode chamber, with a proton exchange membrane installed between the two chambers to selectively transfer hydrogen ions and prevent cross-diffusion of gases. The reaction liquid from the primary reactor 2 and the secondary reactor 3 enters the electrolytic cell, and the system contains both water molecules and multivalent metal ions such as Fe produced from the dissolution of oil shale.

[0072] At the cathode (negative electrode), the migrating hydrogen ions ( Electrons are gained at the electrode surface, generating hydrogen gas, which is then collected in the hydrogen storage tank 6. At the anode (positive electrode). Multivalent metal ions lose electrons and are oxidized to This process partially replaces the oxygen evolution reaction in conventional water electrolysis. It significantly reduces the reaction potential at the anode, resulting in a decrease in the overall voltage required for electrolysis and a reduction in energy consumption.

[0073] Product collection and separation

[0074] The gas outlet of the electrolytic hydrogen production unit 4 is connected to the hydrogen storage tank 6 via a gas-liquid separator and a check valve in series. A safety relief valve and a drying and purification unit are sequentially installed on the pipeline to remove entrained water vapor and acid mist, ensuring hydrogen purity and system safety. The liquid outlet of the electrolytic hydrogen production unit 4 is returned to the sulfuric acid storage tank 1 via a circulation pipeline. The acid concentration is monitored by an online density / refractive index sensor, and the sulfuric acid concentration is maintained at a stable 40% by supplementing with water and diluting the concentrated sulfuric acid. The concentration control valve is controlled by a PID loop to ensure uniform mixing of the returned electrolyte and the newly added acid, meeting subsequent liquid supply requirements. Solid residue from the secondary reactor 3 is introduced into the by-product collection device 5. After washing / neutralizing to near neutrality and drying, the solids are collected and treated to obtain solid by-products such as silica and calcium sulfate. The separated clarified liquid and the returned acid are combined and fed into the sulfuric acid storage tank 1, forming a closed-loop acid supply to the primary reactor 2 and the secondary reactor 3.

[0075] The oil shale-assisted water electrolysis hydrogen production system provided by this invention has the following advantages:

[0076] Modular design: The system consists of feed pretreatment, primary reactor 2, secondary reactor 3, electrolysis hydrogen production unit 4, and green treatment unit. The functional areas are clearly defined, which facilitates independent optimization and maintenance.

[0077] Synergistic reaction structure: The primary reactor 2 and the secondary reactor 3 are arranged in series to ensure that the oil shale and electrolyte can react step by step, thereby improving the conversion efficiency.

[0078] Coupled electrolyzer design: The electrolysis hydrogen production unit 4 is closely coupled with the oil shale reaction system, which not only provides a hydrogen source, but also utilizes the electrons or free radicals released by the oil shale reaction to reduce power consumption.

[0079] Byproduct collection device 5: A solid separation and collection unit is added at the end of the system to achieve efficient recovery of silica and calcium sulfate byproducts and avoid secondary pollution.

[0080] Flexible scalability: Each module is connected to valves via pipelines, and the unit can be expanded or coupled with existing electrolytic cells / oil shale processing equipment as needed.

[0081] Reduced energy consumption: By utilizing the synergistic effect of organic matter and minerals in oil shale, the energy required for water electrolysis can be partially replaced, effectively reducing electrolysis voltage and operating costs.

[0082] Improving hydrogen production efficiency: The reaction process between oil shale and electrolyte releases free radicals or provides electrons, which significantly promotes the increase of hydrogen production.

[0083] Byproduct resource utilization: The silicon dioxide and calcium sulfate generated in the reaction can be used as building materials or chemical raw materials, realizing the green treatment of solid waste.

[0084] Environmental friendliness: It avoids the high energy consumption and environmental pollution problems associated with traditional oil shale dry distillation or combustion, achieving the goal of clean utilization.

[0085] Versatile adaptability: It can be widely used in many fields such as new energy hydrogen production, petrochemical by-product treatment, and harmless disposal of solid minerals.

[0086] Enhanced economic efficiency: By comprehensively utilizing oil shale, the overall economic benefits of the system are improved, taking into account both energy production efficiency and environmental protection value.

[0087] Based on the above system, the present invention provides the following specific implementation process:

[0088] Example 1

[0089] Raw material conditions: Oil shale crushed to a particle size of 0.5–2 mm.

[0090] Acid conditions: The sulfuric acid concentration is maintained at 40%, and it is delivered from sulfuric acid storage tank 1 via a metering pump.

[0091] Reaction conditions: Primary reactor 2 temperature 60℃, reaction time 1 h; Secondary reactor 3 temperature 70℃, residence time 1.5 h.

[0092] Electrolysis conditions: Electrolytic cell voltage 1.1V, current density 10mA / cm², operation for 2 hours.

[0093] Comparative Example 1

[0094] The experiment was conducted using traditional water electrolysis with a 40% dilute sulfuric acid solution as the raw material and no oil shale was added. No oil shale was added to either the primary reactor 2 or the secondary reactor 3, and the other reaction conditions were the same as in Example 1. The running time was 2 hours, and the electrolysis voltage was measured to be 1.8V and the current density to be 8mA / cm².

[0095] The hydrogen yield and power consumption of Example 1 and Comparative Example 1 are compared and calculated as follows:

[0096] Theoretical basis

[0097] Theoretical formula for hydrogen production by electrolysis

[0098] According to Faraday's law of electrolysis, the amount of hydrogen produced during electrolysis is directly proportional to the current intensity (I) and the electrolysis time (t), as shown in the formula:

[0099]

[0100] in: The mass of hydrogen gas is expressed in grams. The current intensity is (A). Electrolysis time (s) The molar mass of hydrogen gas is 2 g / mol. It is the electron transfer number (2, corresponding to 2H+ + 2e- → H2). It is the Faraday constant (96485 C / mol).

[0101] Based on the above theoretical basis, under the same electrolysis time and electrode area, the hydrogen yield and current density ( It is directly proportional to A / cm2.

[0102] Example 1: Oil shale-assisted electrolysis: current density 10 mA / cm2, electrolysis time 2 hours (7200 seconds), voltage 1.1 V.

[0103] Comparative Example 1: Electrolysis of water alone: ​​current density 8 mA / cm2, electrolysis time 2 hours (7200 seconds), voltage 1.8V.

[0104] Calculation and comparison process

[0105] The calculation of the hydrogen yield increase ratio is based on the fact that hydrogen production is directly proportional to current density. The formula for the increase ratio is as follows:

[0106]

[0107] Substitute data

[0108]

[0109] The power consumption calculation process is as follows:

[0110] Reduced power consumption

[0111] Reduced power consumption

[0112] The above calculations show that the hydrogen yield of this invention is increased by approximately 25% compared to water electrolysis alone, while power consumption is reduced by 39% (the actual engineering voltage for traditional water electrolysis hydrogen production is calculated at 1.8V, (1.1-1.8=-0.7 / 1.8=-0.388889≈39%)); the main byproduct is high-purity hydrogen. and It can be directly recycled.

[0113] Extensive exploratory experiments were conducted before designing the oil shale-assisted water electrolysis hydrogen production system, which played a crucial role in the system's construction. The experiments mainly included:

[0114] (1) Comparative electrolysis experiments were conducted on oil shale, lignite, and graphite. The results showed that after 12 hours of continuous electrolysis, the current density decreased in the following order: oil shale > lignite > graphite, and the corresponding hydrogen production also showed the same trend. This is attributed to the fact that the organic carbonaceous material and mineral components (especially Fe) in oil shale can effectively promote the hydrogen production process by water electrolysis.

[0115] (2) Under conditions below the theoretical minimum decomposition voltage of water electrolysis (<1.23 V), the liquid phase of the oil shale slurry after solid-liquid separation was electrolyzed, and the current density was increased by about 20% ((12-10) / 10=20%) compared with the above direct electrolysis of the slurry, reaching... The current density is relatively evenly distributed within the first 12 hours. However, the high current density is maintained for a short time and decays rapidly.

[0116] (3) The solid phase sample obtained after the first electrolysis of oil shale was repeatedly washed with deionized water until the pH was neutral and then dried before being electrolyzed again. The current density was significantly increased. However, it gradually dropped back to the final level of the first electrolysis after 30 minutes. Surface observation showed that the morphology of the solid phase before and after the second electrolysis was almost unchanged, but the carbonate was effectively removed, indicating that the carbonate played a certain inhibitory role in the electrolysis process. However, considering that the carbonate formation rate is relatively fast, the main factor that really leads to the decrease in electrolysis efficiency should be the insoluble organic matter generated during the electrolysis process.

[0117] (4) Under conditions below the theoretical minimum voltage for water electrolysis (<1.23 V), after 12 hours of electrolysis, the current density is maintained at approximately At this point, a large amount of silicates and carbonates accumulate on the surface of the solid phase, accompanied by the formation of an organic film that is insoluble in the electrolyte, severely hindering the reduction reaction. After washing with water, soaking in acetone, and drying, the solid phase is electrolyzed again, and the current density recovers to [previous value]. This indicates that insoluble organic matter was effectively removed and the electrode condition was significantly improved.

[0118] The above description is merely a preferred embodiment of the present invention. However, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention should be covered within the scope of protection of the present invention.

Claims

1. An oil shale assisted electrolysis water hydrogen production system, characterized in that, The device comprises an oil shale pretreatment and feeding device, a sulfuric acid storage tank, a primary reactor, an oil shale cleaning device, a secondary reactor, an electrolytic hydrogen production device, a byproduct collection device, a hydrogen storage tank and a carbon dioxide storage tank, which are sequentially connected by pipelines. The discharge port of the pretreatment and feeding device is connected to the feeding port of the primary reactor for conveying oil shale particles. The sulfuric acid storage tank is connected to the acid liquid inlets of the primary reactor and the secondary reactor. The solid residue outlet of the primary reactor is connected to the oil shale cleaning device, the reaction liquid outlet is connected to the secondary reactor, and the gas outlet is connected to the carbon dioxide storage tank. The discharge port of the oil shale cleaning device is connected to the residue inlet of the secondary reactor. The reaction liquid outlet of the secondary reactor is connected to the anode chamber of the electrolytic hydrogen production device, and the solid residue outlet is connected to the byproduct collection device. The cathode chamber gas outlet of the electrolytic hydrogen production device is connected to the hydrogen storage tank, and the anode chamber waste liquid outlet is connected to the sulfuric acid storage tank through a reflux pipeline. The electrolytic hydrogen generation device further comprises a proton exchange membrane, and the cathode and anode chambers are provided with platinum sheet electrodes, wherein the anode chamber is provided with Fe 2+ / Fe 3+ Redox system The electrolytic voltage of the electrolytic hydrogen production device is 1.1 V ± 0.1 V, and the current density is 10 mA / cm 2 ± 2 mA / cm 2 ; In the first reaction stage, in the first reactor, first, acidolysis reaction occurs between sulfuric acid and carbonate minerals contained in oil shale, and the generated carbon dioxide is directly transported to the carbon dioxide storage tank through a pipeline for collection; then, sulfuric acid continues to act on the mineral framework of oil shale, dissolving metal cations therein, so that they enter the reaction solution; in addition, the residual organic carbon in oil shale exhibits strong reducibility in an acidic environment, and the generated Fe 3+ is reduced to Fe 2+ again, forming a local Fe 2+ / Fe 3+ circulation system, and part of the dissolved sulfuric acid solution is introduced into the anode area of the electrolytic hydrogen production device through a pipeline, and the residual oil shale solid is discharged from the first reactor together with the reaction solution, wherein the solid part is transported to the oil shale cleaning device, and the liquid part can directly flow into the secondary reactor or the sulfuric acid storage tank for further decomposition and conversion; In the oil shale cleaning device, the reacted oil shale residue is first washed by circulating liquid to remove the surface residual sulfuric acid and part of the soluble impurities. The cleaned oil shale residue and the reaction liquid from the primary reactor are jointly introduced into the secondary reactor for further decomposition and conversion reaction. Part of the newly supplemented dilute sulfuric acid is introduced into the device to maintain the acidic environment and ionic strength of the reaction liquid. In this stage, the unreacted carbonaceous components in the residue continue to play a reducing role, and part of the accumulated Fe 3+ is reduced to Fe 2+ , thereby maintaining a high concentration of ferrous ions in the system. The liquid product formed after the secondary reaction flows into the electrolytic hydrogen production device and participates in the electrolysis process in the anode area, further promoting the generation of hydrogen. The excess acid liquid that is not completely consumed in the electrolysis process is returned to the sulfuric acid storage tank through the circulation pipeline for regeneration and recycling. In the electrolysis stage, a proton exchange membrane is arranged between the cathode chamber and the anode chamber of the electrolytic hydrogen production device for selectively transmitting hydrogen ions. At the cathode, the migrated hydrogen ions get electrons at the electrode surface, generating hydrogen gas and being collected to a hydrogen storage tank, at the anode, Fe 2+ loses electrons and is oxidized to Fe 3+ , thus partially replacing the oxygen evolution reaction in conventional water electrolysis.

2. The system for hydrogen production from oil shale by assisted electrolysis of water according to claim 1, characterized in that The reaction liquid from the primary reactor and the secondary reactor enters the electrolytic cell, and the system contains both water molecules and Fe multi-valence metal ions produced by the dissolution of oil shale.

3. The system for hydrogen production from oil shale by auxiliary electrolysis of water according to claim 2, characterized in that The oil shale cleaning device comprises a circulating liquid washing unit and an organic solvent cleaning unit.

4. The system for hydrogen production from oil shale by assisted electrolysis of water according to claim 1, characterized in that, The organic solvent in the organic solvent cleaning unit is acetone or dichloromethane.

5. The system for hydrogen production from oil shale by assisted electrolysis of water according to claim 1, characterized in that, The primary reactor and the secondary reactor are arranged in series, the temperature of the primary reactor is 60℃±10℃, and the temperature of the secondary reactor is 10℃ higher than that of the primary reactor.

6. The system for hydrogen production from oil shale by assisted electrolysis of water according to claim 1, characterized in that, The byproduct collection device comprises a solid-liquid separation unit and a drying unit for recycling silica and calcium sulfate solid byproducts.

7. The system for hydrogen production from oil shale assisted electrolysis of water according to any one of claims 1-6, characterized in that, The sulfuric acid storage tank is provided with a PID concentration control system, the feeding rate is linked to the acid liquid supply amount of the primary reactor, and the PID concentration control system is used to maintain the concentration of dilute sulfuric acid at 40%±2%. The particle size of the oil shale particles is 0.5-2mm.

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