Hydrogen concentration process based on hydrate technology
Through the pretreatment, reaction and separation process of hydrate technology, the problems of high energy consumption and high cost of hydrogen concentration are solved, and efficient, energy-saving and environmentally friendly hydrogen concentration are achieved, which improves hydrogen recovery and purity and reduces production costs.
Patent Information
- Application Number
- CN202510719695.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-08-15
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing hydrogen enrichment technology has high energy consumption and high cost, which is difficult to meet the needs of large-scale industrial production. The traditional methods and equipment are complex, the maintenance costs are high, and the resource utilization rate is low.
Using hydrate technology, the selective enrichment of hydrogen is achieved through pretreatment, hydrate reaction, separation and decomposition processes, including cyclone separation, bag filtration, drying, desulfurization and decarbonization, activated carbon adsorption and membrane filtration, reducing energy consumption and improving resource utilization.
Significantly reduce energy consumption, reduce production carbon emissions, reduce equipment maintenance and material replacement costs, improve hydrogen recovery and purity, realize resource recycling, and be cost-effective.
Smart Images
Figure CN120483046A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of hydrogen separation and purification, and in particular to a hydrogen concentration process based on hydrate technology. Background Art
[0002] As a clean energy carrier and important industrial raw material, hydrogen's applications in the energy and chemical industries are constantly expanding, and requirements for its purity and recovery rate are becoming increasingly stringent. Currently, hydrogen enrichment technologies primarily rely on traditional methods such as pressure swing adsorption, membrane separation, and cryogenic separation, but these technologies present numerous challenges that need to be addressed.
[0003] Although pressure swing adsorption technology can achieve hydrogen separation, the equipment investment cost is high, and the adsorbent is easily poisoned and inactivated by impurities in the raw gas during use, resulting in a generally low hydrogen recovery rate, which is difficult to meet the needs of large-scale and efficient production.
[0004] Membrane separation technology is limited by the performance of membrane materials. Balancing selectivity and permeability is difficult, leading to bottlenecks in improving separation efficiency. Furthermore, membrane materials have a limited lifespan, and frequent replacement further increases operating costs. Cryogenic separation technology, on the other hand, requires operation at extremely low temperatures, resulting in significant energy consumption, complex equipment, and high maintenance costs, limiting its widespread adoption. Summary of the Invention
[0005] The purpose of the present invention is to provide a hydrogen concentration process based on hydrate technology, which solves the problems of high energy consumption and high cost of traditional hydrogen concentration technology and its difficulty in meeting the needs of large-scale industrial production.
[0006] To achieve the above objectives, the present invention provides a hydrogen concentration process based on hydrate technology, comprising the following steps:
[0007] pre-treating the mixed raw gas containing hydrogen;
[0008] The pretreated raw gas is passed into a hydrate reactor, and water and a promoter are added to the reactor, so that the gases other than hydrogen in the mixed gas react with water to form hydrates, while the hydrogen exists in the reactor in gaseous form;
[0009] The materials in the hydrate reactor are separated by a three-phase separator, hydrogen is discharged from the gas phase outlet of the three-phase separator, and hydrate solids and part of the water are discharged from the solid phase and liquid phase outlets;
[0010] The separated hydrate solid is sent to a hydrate decomposition device to decompose the hydrate into gas and water.
[0011] Wherein, in “pre-treating the mixed raw gas containing hydrogen”, the method includes:
[0012] The mixed raw gas is passed into the cyclone separator to initially separate larger particle impurities;
[0013] The gas after preliminary separation enters the bag filter to further remove tiny solid particles.
[0014] Wherein, in “pre-treating the mixed raw gas containing hydrogen”, the method further comprises:
[0015] The gas after being treated by the bag filter enters the drying tower to dry the gas and remove the moisture contained in the gas;
[0016] The dried gas is passed into the desulfurization and decarbonization device to remove acidic gases such as hydrogen sulfide and carbon dioxide in the gas;
[0017] The treated gas is passed through a heater to adjust the temperature so that the raw gas reaches the feed conditions required by the hydrate reactor.
[0018] The hydrogen concentration process based on hydrate technology further comprises the following steps:
[0019] The hydrogen separated by the three-phase separator enters the activated carbon adsorption tower to remove trace moisture, organic compounds and other impurities remaining in the hydrogen;
[0020] The adsorbed hydrogen enters the membrane filter, where tiny particles and impurities in the hydrogen are further removed through membrane filtration, ultimately obtaining a hydrogen product with purity that meets the requirements.
[0021] Among them, in "the hydrogen separated by the three-phase separator enters the activated carbon adsorption tower to remove trace moisture, organic compounds and other impurities remaining in the hydrogen":
[0022] The adsorption capacity of activated carbon is not less than 50mg / g, and the gas velocity in the tower is 2-5m 3 / (h·m 3 ), the adsorption temperature is room temperature.
[0023] Among them, in "After adsorption, the hydrogen enters the membrane filter, and the membrane filtration further removes the tiny particles and impurities in the hydrogen, and finally obtains a hydrogen product with purity that meets the requirements":
[0024] The membrane material is polyvinylidene fluoride (PVDF) hollow fiber membrane with a membrane pore size of 0.01 μm and an operating pressure of 0.3-0.5 MPa.
[0025] The hydrogen concentration process based on hydrate technology further comprises the following steps:
[0026] The water produced by hydrate decomposition and the recyclable materials produced during the hydrogen refining process are recovered and treated.
[0027] The hydrogen concentration process based on hydrate technology of the present invention, in terms of energy consumption, compared with the high energy consumption characteristic of cryogenic separation technology that needs to operate at extremely low temperatures, this process does not require an extremely low temperature environment, and realizes hydrogen concentration through the hydrate formation and decomposition process, effectively reducing energy consumption and greatly reducing carbon emissions in the production process, which is in line with the concept of green environmental protection and sustainable development; in terms of cost control, it overcomes the problems of large equipment investment in pressure swing adsorption technology, easy poisoning and deactivation of adsorbents, and frequent replacement of membrane materials in membrane separation technology, reduces equipment maintenance and material replacement costs, and achieves low-cost hydrogen concentration by optimizing process steps, significantly improving economic benefits; in addition, the process processes the water generated by hydrate decomposition and the treatment of recyclable materials in the hydrogen refining process, realizes the recycling of resources, which not only reduces production costs, but also reduces waste emissions, and improves the environmental protection and resource utilization of the entire process.
[0028] In summary, the present invention provides a new approach for hydrogen enrichment that is efficient, energy-saving, economical and environmentally friendly, and has broad application prospects and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art.
[0030] Figure 1 This is a flow chart of the hydrogen concentration process based on hydrate technology of the present invention.
[0031] Figure 2 This is a flow chart of the present invention for pretreating mixed raw gas containing hydrogen. DETAILED DESCRIPTION
[0032] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be understood as limiting the present invention.
[0033] The present invention provides a hydrogen concentration process based on hydrate technology, comprising the following steps:
[0034] S101: pre-treating the mixed raw gas containing hydrogen.
[0035] S102: The pretreated raw gas is passed into a hydrate reactor, and water and a promoter are added to the reactor, so that the gases other than hydrogen in the mixed gas react with water to form hydrates, while the hydrogen exists in the reactor in gaseous form.
[0036] Specifically, the hydrate reactor is made of stainless steel with a jacket. The volume is determined according to the gas processing volume. Coolant is introduced into the jacket to control the reaction temperature. A stirring paddle is installed in the reactor, and the stirring paddle speed is controlled at 100-300 rpm to ensure sufficient mixing of the gas-liquid-solid three phases. The amount of promoter added is optimized according to the feed gas composition and hydrate formation conditions: for feed gas containing gases such as methane and carbon dioxide, the added mass fraction of tetrabutylammonium bromide is generally controlled at 0.5-1.5%; for feed gas containing gases such as nitrogen and carbon monoxide, the added mass fraction of cyclopentane is controlled at 0.3-1%. The promoter is accurately added to the reactor via a metering pump.
[0037] S103: The materials in the hydrate reactor are separated by a three-phase separator, hydrogen is discharged from the gas phase outlet of the three-phase separator, and hydrate solids and part of the water are discharged from the solid phase and liquid phase outlets.
[0038] Specifically: A cyclone-gravity composite three-phase separator is used. After the gas enters the separator, it is first separated by the cyclone component, so that most of the solid particles and liquid are thrown to the wall of the separator. Then, under the action of gravity, the gas, solid and liquid are further separated. A gas-liquid coalescer is set at the gas phase outlet of the three-phase separator to further remove the tiny droplets carried in the gas, ensuring that the droplet content of the outlet hydrogen is less than 5mg / m 3 Liquid level controllers are installed at the solid phase and liquid phase outlets to maintain a stable liquid level in the separator by controlling the opening of the discharge valve to prevent gas from escaping from the solid phase and liquid phase outlets.
[0039] S104: The separated hydrate solid is sent to a hydrate decomposition device to decompose the hydrate into gas and water.
[0040] Specifically: hydrate decomposition can be carried out by pressure reduction decomposition or heating decomposition, or by a combination of pressure reduction and heating. During pressure reduction decomposition, the hydrate is fed into a decomposition kettle, and the pressure is gradually reduced from the hydrate formation pressure to 0.1-0.2 MPa. The decomposition time is determined according to the amount of hydrate. During heating decomposition, heat transfer oil is introduced into the jacket of the decomposition kettle, and the temperature is controlled at 20-40°C to decompose the hydrate by heat.
[0041] S105: The hydrogen separated by the three-phase separator enters the activated carbon adsorption tower to remove impurities such as trace moisture and organic compounds remaining in the hydrogen.
[0042] Specifically: Hydrogen first enters the activated carbon adsorption tower. The adsorption capacity of the activated carbon is not less than 50mg / g, and the gas velocity in the tower is controlled at 2-5m 3 / (h·m 3 ), the adsorption temperature is room temperature, and the trace moisture, organic compounds and other impurities remaining in the hydrogen are removed by activated carbon adsorption.
[0043] S106: The adsorbed hydrogen enters the membrane filter, where it is filtered to further remove tiny particles and impurities in the hydrogen, ultimately obtaining a hydrogen product with purity that meets the requirements.
[0044] Specifically: The hydrogen after adsorption enters the membrane filter. The membrane material is polyvinylidene fluoride (PVDF) hollow fiber membrane with a pore size of 0.01μm and an operating pressure of 0.3-0.5MPa. The membrane filtration further removes tiny particles and impurities in the hydrogen, and finally obtains a hydrogen product with purity that meets the requirements.
[0045] S107: Recover and process the water produced by the decomposition of the hydrate and the recyclable substances produced during the hydrogen refining process.
[0046] Specifically, the circulating water produced by hydrate decomposition must be regularly tested for water quality indicators such as pH, conductivity, and microbial count before recycling. When the pH deviates from the 6-8 range, it is adjusted by adding an acid-base regulator. When the conductivity exceeds 50μS / cm, ion exchange treatment is performed. When the microbial count exceeds the standard, UV disinfection or the addition of a fungicide is performed. Exhaust gas generated during adsorbent regeneration during the hydrogen refining process is treated differently depending on its composition: Exhaust gas containing organic compounds is treated using a catalytic combustion device; Exhaust gas containing harmless gases such as water vapor is directly discharged after condensation and water recovery. The regenerated adsorbent can be reactivated and put back into use.
[0047] Wherein, in “pre-treating the mixed raw gas containing hydrogen”, the method includes:
[0048] S201: The mixed raw gas is passed into a cyclone separator to initially separate larger particle impurities.
[0049] Specifically: The mixed raw gas first enters the cyclone separator, which uses the centrifugal force principle to preliminarily separate larger particle impurities. The gas flow rate at the cyclone separator inlet is controlled at 15-25m / s, and the separation efficiency can reach 80-90%.
[0050] S202: The gas after preliminary separation enters the bag filter to further remove tiny solid particles.
[0051] Specifically: The gas then enters the bag filter, which is made of polytetrafluoroethylene with a filtration accuracy of 0.3μm, to further remove tiny solid particles and ensure that the dust content of the gas entering the subsequent process is less than 1mg / m 3 .
[0052] S203: The gas after being processed by the bag filter enters the drying tower, where the gas is dried to remove moisture contained in the gas.
[0053] Specifically: The dehydration process adopts two-stage drying: the first stage uses a 3A molecular sieve drying tower, and the gas is dried at 5-10m 3 / (h·m 3 ) through the tower, reducing the water content of the gas from the initial level to about 50ppm. The secondary drying uses an activated alumina drying tower, and the gas tower velocity is controlled at 3-8m 3 / (h·m 3 ), ultimately reducing the water content of the gas to below 5ppm. The drying tower adopts a dual-tower parallel switching operation mode. When one tower is working, the other tower is regenerated. The regeneration temperature is controlled at 200-250°C. The regeneration gas is dried nitrogen, and the flow rate is 20-30% of the gas flow during operation.
[0054] S204: The dried gas is passed into a desulfurization and decarbonization device to remove acidic gases such as hydrogen sulfide and carbon dioxide from the gas.
[0055] Specifically: Acid gas removal adopts packed tower absorption process, with 20% ethanolamine solution as absorbent, and the liquid-gas ratio of absorbent to gas is controlled at 3-5L / m 3 , the operating temperature is 30-40℃ and the pressure is 0.5-1MPa, which can reduce the carbon dioxide content to below 10ppm and the hydrogen sulfide content to below 1ppm.
[0056] S205: The treated gas is passed through a heater to adjust the temperature so that the raw gas reaches the feed conditions required by the hydrate reactor.
[0057] First embodiment:
[0058] The mixed raw gas containing hydrogen (60% by volume), methane (30% by volume) and carbon dioxide (10% by volume) was heated to 100 m 3 The gas is passed through a pretreatment device at a flow rate of / h. First, it passes through a filter with a filtration accuracy of 0.1μm to remove solid particles. Then it passes through a drying tower filled with 3A molecular sieve for dehydration to reduce the water content of the gas to below 5ppm. Finally, a 20% ethanolamine solution is used to absorb carbon dioxide to reduce the carbon dioxide content to below 10ppm.
[0059] The pretreated feed gas was passed into a hydrate reactor equipped with a stirrer. Water (10% by volume of the feed gas) and 1% by mass of tetrabutylammonium bromide were added as a promoter. The reactor temperature was controlled at 2°C and the pressure was maintained at 4 MPa. Under these conditions, methane and carbon dioxide reacted with water to form hydrates. The reaction lasted for one hour.
[0060] The materials in the hydrate reactor are separated by a solid-liquid-gas three-phase separator, and hydrogen is discharged from the gas phase outlet at a speed of 85m 3 / h, and the hydrate solid and part of the water are discharged from the solid phase and liquid phase outlets.
[0061] The separated hydrate solids are fed into a vacuum decomposition reactor, where the pressure is reduced to 0.1 MPa, decomposing the hydrate into gas and water. The resulting methane and carbon dioxide gases can be collected and used for other industrial purposes, while the water produced by decomposition is filtered, disinfected, and recycled back into the hydrate reactor.
[0062] The hydrogen obtained from gas-solid separation is refined by passing through an adsorption tower filled with activated carbon and a membrane filter with a pore size of 0.01 μm to remove trace moisture, organic compounds and tiny particles remaining in the hydrogen, obtaining a hydrogen product with a purity of 99.9%.
[0063] The waste gas generated by the regeneration of the activated carbon adsorption tower during the hydrogen refining process is collected and treated. The organic compounds in it can be treated by combustion, and harmless gases such as water vapor can be discharged; the water generated by the decomposition of hydrates is recycled to achieve efficient utilization of resources.
[0064] First embodiment:
[0065] For the mixed raw gas containing hydrogen (50% by volume), nitrogen (35% by volume), and carbon monoxide (15% by volume), the 3 The gas is pre-treated at a flow rate of / h. Similarly, it is first filtered, dried with molecular sieves, and acid gas (if present) is removed with alkaline absorbents to make the gas meet the requirements for subsequent hydrate formation.
[0066] The pretreated feed gas was passed into a hydrate reactor, where 12% water and 0.8% cyclopentane were added as a promoter. The reactor temperature was controlled at 1°C and the pressure at 5 MPa for 1.5 hours to allow nitrogen and carbon monoxide to form hydrates.
[0067] Referring to the method of Example 1, gas-solid separation, hydrate decomposition, hydrogen refining and recycling operations were carried out in sequence, and finally a hydrogen product with a purity of 99.8% was obtained, and the hydrogen recovery rate reached 88%.
[0068] The above disclosure is merely one or more preferred embodiments of the present application and is not intended to limit the scope of the present application. A person skilled in the art will understand that all or part of the processes of the above embodiments and equivalent changes made in accordance with the claims of the present application are still within the scope of the present application.
Claims
1. A hydrogen enrichment process based on hydrate technology, characterized in that: The following steps are involved: pre-treating the mixed raw gas containing hydrogen; The pretreated raw gas is passed into a hydrate reactor, and water and a promoter are added to the reactor, so that the gases other than hydrogen in the mixed gas react with water to form hydrates, while the hydrogen exists in the reactor in gaseous form; The materials in the hydrate reactor are separated by a three-phase separator, hydrogen is discharged from the gas phase outlet of the three-phase separator, and hydrate solids and part of the water are discharged from the solid phase and liquid phase outlets; The separated hydrate solid is sent to a hydrate decomposition device to decompose the hydrate into gas and water.
2. The hydrogen concentration process based on hydrate technology according to claim 1, characterized in that: In the step of "pre-treating the mixed feed gas containing hydrogen", the method comprises: The mixed raw gas is passed into the cyclone separator to initially separate larger particle impurities; The gas after preliminary separation enters the bag filter to further remove tiny solid particles.
3. The hydrogen concentration process based on hydrate technology according to claim 2, characterized in that: In the step of "pre-treating the mixed feed gas containing hydrogen", the method further comprises: The gas after being treated by the bag filter enters the drying tower to dry the gas and remove the moisture contained in the gas; The dried gas is passed into the desulfurization and decarbonization device to remove acidic gases such as hydrogen sulfide and carbon dioxide in the gas; The treated gas is passed through a heater to adjust the temperature so that the raw gas reaches the feed conditions required by the hydrate reactor.
4. The hydrogen concentration process based on hydrate technology according to claim 1, characterized in that: The hydrogen concentration process based on hydrate technology also includes the following steps: The hydrogen separated by the three-phase separator enters the activated carbon adsorption tower to remove trace moisture, organic compounds and other impurities remaining in the hydrogen; The adsorbed hydrogen enters the membrane filter, where tiny particles and impurities in the hydrogen are further removed through membrane filtration, ultimately obtaining a hydrogen product with purity that meets the requirements.
5. The hydrogen concentration process based on hydrate technology according to claim 4, characterized in that: In "The hydrogen separated by the three-phase separator enters the activated carbon adsorption tower to remove trace moisture, organic compounds and other impurities remaining in the hydrogen": The adsorption capacity of activated carbon is not less than 50mg / g, and the gas velocity in the tower is 2-5m 3 / (h·m 3 ), the adsorption temperature is room temperature.
6. The hydrogen concentration process based on hydrate technology according to claim 4, characterized in that: In "After adsorption, the hydrogen enters the membrane filter, where it is further filtered to remove tiny particles and impurities, ultimately obtaining a hydrogen product with purity that meets the requirements": The membrane material is polyvinylidene fluoride (PVDF) hollow fiber membrane with a membrane pore size of 0.01 μm and an operating pressure of 0.3-0.5 MPa.
7. The hydrogen concentration process based on hydrate technology according to claim 1, characterized in that: The hydrogen concentration process based on hydrate technology also includes the following steps: The water produced by hydrate decomposition and the recyclable materials produced during the hydrogen refining process are recovered and treated.