Ammonia-hydrogen combustion coupled ammonia decomposition hydrogen production system
By introducing combustion units and multi-stage heat exchange and membrane separation and purification technologies into the ammonia decomposition hydrogen production system, the problems of low energy utilization efficiency and complex equipment in traditional systems are solved, and efficient hydrogen preparation and purity improvement are achieved.
Patent Information
- Application Number
- CN202421808837.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-29
- Publication Date
- 2025-06-10
- Estimated Expiration
- 2034-07-29
AI Technical Summary
The traditional ammonia decomposition hydrogen production system has problems such as low energy utilization efficiency, difficult reaction temperature control, and complex equipment, which limits its promotion in practical applications.
The ammonia hydrogen combustion coupled ammonia decomposition hydrogen production system is adopted. By introducing a combustion unit and an ammonia decomposition unit, the heat generated by combustion provides a heat source for the ammonia decomposition reaction, achieving efficient energy utilization and precise control of reaction temperature, and using multi-stage heat exchange and membrane separation and purification technology to improve the purity and yield of hydrogen.
It realizes efficient energy utilization and precise control of reaction temperature, improves the purity and yield of hydrogen, and reduces the complexity and maintenance costs of the system.
Smart Images
Figure CN222961141U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of hydrogen energy, in particular to an ammonia-hydrogen combustion coupled ammonia decomposition hydrogen production system. Background Art
[0002] With the transformation of the global energy structure and the improvement of environmental protection awareness, hydrogen energy, as a clean, efficient and renewable energy, is gradually attracting the attention of governments and research institutions around the world. Hydrogen energy not only has the advantages of high calorific value and zero emissions, but also has broad application prospects in many fields such as energy storage, transportation and industry. However, the storage and transportation of hydrogen have always been bottleneck problems restricting its large-scale application.
[0003] Traditional hydrogen storage methods such as high-pressure gaseous storage, liquid storage and solid storage all have problems such as high cost, poor safety or great technical difficulty. In contrast, ammonia, as a liquid substance that is easy to store and transport, has a higher volumetric energy density than liquid hydrogen and higher safety, so it is regarded as a potential medium for hydrogen storage and transportation.
[0004] Ammonia decomposition hydrogen production technology is a method of decomposing ammonia molecules to produce hydrogen and nitrogen, which has the advantages of wide raw material sources, simple reaction process and high product purity. However, traditional ammonia decomposition hydrogen production systems often have problems such as low energy utilization efficiency, difficult reaction temperature control and complex equipment, which limit their popularization in practical applications. Content of the Utility Model
[0005] Aiming at the deficiencies of the prior art, the utility model provides an ammonia-hydrogen combustion coupled ammonia decomposition hydrogen production system. By introducing a combustion unit combined with an ammonia decomposition unit, the system uses the heat generated by combustion as the heat source for the ammonia decomposition reaction to achieve efficient energy utilization and precise control of the reaction temperature. At the same time, the system also adopts multi-stage heat exchange and membrane separation and purification technologies to further improve the purity and yield of hydrogen.
[0006] The utility model adopts the following technical solutions:
[0007] The utility model provides an ammonia-hydrogen combustion coupled ammonia decomposition hydrogen production system, which includes a liquid ammonia storage device, a vaporizer, a second heat exchanger, an ammonia decomposition reactor, a membrane separation and purification device, a radiator and a hydrogen collector; the liquid ammonia storage device is communicated with the vaporizer for vaporizing liquid ammonia into ammonia gas; the second heat exchanger includes a second cold heat exchange channel and a second hot heat exchange channel, the ammonia decomposition reactor includes an ammonia decomposition reaction ammonia gas channel and an ammonia decomposition reaction flue gas channel, the membrane separation and purification device includes a purified gas channel and a residual gas channel, and the membrane separation and purification device is separated by a metal alloy separation membrane for purification. The gas passing through the separation membrane is the purified gas, and the gas not passing through the separation membrane is the residual gas and enters the residual gas channel; the outlet of the vaporizer is communicated with the inlet of the second cold heat exchange channel, and the outlet of the second cold heat exchange channel is communicated with the inlet of the ammonia decomposition reaction ammonia gas channel, and the ammonia gas after heat exchange by the second heat exchanger is introduced into the ammonia decomposition reactor for ammonia decomposition; the outlet of the ammonia decomposition reaction ammonia gas channel is communicated with the inlet of the second hot heat exchange channel, and the outlet of the second hot heat exchange channel is communicated with the inlet of the purified gas channel. The product mixed gas after decomposition by the ammonia decomposition reactor is used as the heat exchange medium of the second heat exchanger to exchange heat with the ammonia gas passing through the second cold heat exchange channel and then introduced into the membrane separation and purification device for hydrogen purification; the outlet of the purified gas channel is successively connected in series with the radiator and the hydrogen collector for cooling and collecting the purified hydrogen.
[0008] The system further includes a first heat exchanger and a burner. The first heat exchanger includes a first cold heat exchange channel and a first hot heat exchange channel. The outlet of the vaporizer is communicated with the inlet of the first cold heat exchange channel, and the outlet of the first cold heat exchange channel is communicated with the second cold heat exchange channel to perform the first heat exchange and temperature rise on the ammonia gas vaporized by the vaporizer through the first heat exchanger; the outlet of the residual gas channel is communicated with the inlet of the burner, the outlet of the burner is communicated with the inlet of the ammonia decomposition reaction flue gas channel, the outlet of the ammonia decomposition reaction flue gas channel is communicated with the inlet of the first hot heat exchange channel, and the high-temperature flue gas generated by the ignition combustion of the mixed gas in the burner provides heat energy for the ammonia decomposition reaction in the ammonia decomposition reactor, and the remaining heat is used for heat exchange of the ammonia gas passing through the first heat exchanger.
[0009] The separation membrane for purification in the membrane separation and purification device is a hydrogen-selective permeable membrane, which can efficiently separate hydrogen from other gases.
[0010] Preferably, the ammonia decomposition reactor is a fixed-bed reactor, and an ammonia decomposition catalyst is filled in the ammonia gas channel of the ammonia decomposition reactor. The reactant ammonia gas flow enters the ammonia gas channel of the ammonia decomposition reactor after flowing out of the second heat exchanger and flows through the ammonia decomposition catalyst to be converted into decomposition products to obtain hydrogen and nitrogen.
[0011] The burner contains an ignition device. Under appropriate fuel flow rate and air flow rate, after successful ignition and stable operation of the device, the air flow rate is 4 to 40 times the ammonia flow rate flowing into the ammonia decomposition reactor. Whether the fuel combustion state is normal is judged by whether the temperature at the burner outlet is not lower than 650 °C.
[0012] The system further includes an air source, a hydrogen gas tank, and a flue gas processor. The air source, the hydrogen gas tank, the outlet of the vaporizer, the outlet of the second heat exchange hot gas channel, and the outlet of the residual gas channel can be simultaneously connected to the inlet of the burner to provide fuel gas and combustion-supporting gas for the burner; the outlet of the first heat exchange hot gas channel is connected to the flue gas processor for purifying the discharged flue gas.
[0013] The further description of the above technical route is as follows:
[0014] The fixed bed reactor is mainly characterized in that the catalyst is filled in the reactor, and the raw material gas passes through the catalyst bed layer at a certain temperature, pressure, and flow rate to form reaction products. In this application, ammonia flowing out of the second heat exchanger enters the fixed bed reactor and forms product nitrogen and hydrogen after passing through the catalyst.
[0015] Due to the heat effect of the reaction in the fixed bed reactor and the non-uniformity of the heat source heating, the temperature of the catalyst bed layer in the reactor, usually called the reaction temperature, is often not uniform at different spatial points and is usually a temperature range. Typically, the temperature difference at different points can be in the range of 10 to 50 °C.
[0016] "Gas hourly space velocity" is a commonly used technical term in the technical route of the fixed bed reactor, which refers to the volume of gas flowing through a unit volume of catalyst per unit time under standard conditions, and its unit is commonly h -1 。
[0017] Reaction conversion rate is a commonly used term by those skilled in the art, which refers to the number of moles of reactants that have undergone a chemical reaction divided by the number of moles of reactants fed. In this application, the ammonia conversion rate can usually be above 95% and can reach close to 100%, that is, no constant amount of ammonia can be detected in the product gas.
[0018] Similar to the conversion rate, the yield is also a commonly used term in this field. For this case, before passing through the separation membrane, the yield of hydrogen is equivalent to the conversion rate of ammonia. Since some of the product hydrogen does not pass through the product separation membrane but enters the residual gas channel, after passing through the separation membrane, the total yield of pure hydrogen is between 60% and 88%; this yield is defined as: after the process parameters of the device reach a stable state, the ratio of the hydrogen flow rate passing through the separation membrane to the ammonia flow rate released from the ammonia source is divided by 1.5. (The reason for dividing by 1.5 is that for the NH 3 decomposition reaction, NH 3= 0.5 N 2 + 1.5 H 2 , the theoretical limit production of hydrogen corresponding to each mole of ammonia is 1.5 moles).
[0019] In this application, the air flow rate control parameters after the device runs stably have been described above. Although technically, the ammonia from the ammonia source and the hydrogen from the hydrogen storage tank can be introduced into the burner for combustion at any time, the preferred usage scenario is that the ammonia from the ammonia source and the hydrogen from the hydrogen storage tank are mainly used for ignition and initial heating during device startup. After the device runs stably, the fuel entering the burner is generally provided by the hydrogen contained in the residual gas in the unpurified residual gas channel coming out of the membrane separator.
[0020] The hydrogen collector can be a hydrogen storage tank, or other devices that directly use the hydrogen flow, or for other purposes, such as entering a fuel cell for use, or entering a hydrogenation reactor for use, etc.
[0021] Some conventional technical operations in this application, such as the control, measurement, and adjustment of temperature, pressure, and flow rate inside components, burner ignition, selection of heat exchangers and radiators, measurement of hydrogen purity or gas components, and tail gas treatment, are not limited to specific implementation methods, as long as the process condition objectives are achieved.
[0022] The technical solution of this utility model has the following advantages:
[0023] A. Through multi-stage heat exchange between the heat generated during ammonia decomposition and the heat generated during combustion, this utility model realizes the efficient recovery and utilization of energy. In particular, the high-temperature flue gas generated by combustion is used to preheat the ammonia entering the ammonia decomposition reactor, reducing energy consumption and improving the overall thermal efficiency of the system.
[0024] B. By introducing a membrane separation and purification device, this utility model efficiently separates and purifies the product gas generated by ammonia decomposition, effectively improving the purity of hydrogen. This is particularly important for application scenarios that require high-purity hydrogen, such as fuel cells, semiconductor manufacturing, etc. The residual gas generated during the membrane separation and purification process (mainly unreacted ammonia and nitrogen, etc.) is sent to the burner for combustion, realizing the resource utilization of the residual gas and avoiding environmental pollution and energy waste.
[0025] C. The system design of this utility model is compact, and each unit is closely connected through effective management of heat exchange and air flow, realizing a high degree of integration of the hydrogen production process. This not only reduces the floor area of the equipment, but also simplifies the operation process, reducing the complexity and maintenance cost of the system.
[0026] E. The utility model can be provided with a control device, which can flexibly control the temperature and intensity of the combustion reaction by adjusting the proportions of hydrogen, air and ammonia in the burner, and further adjust the conditions of the ammonia decomposition reaction to ensure the stable operation of the system under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the specific embodiments of the utility model, the drawings required for the specific embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0028] Figure 1 FIG. 1 is a schematic diagram of the overall structure of the ammonia-hydrogen combustion coupled ammonia decomposition hydrogen production system (I);
[0029] Figure 2 FIG. 2 is a schematic diagram of the overall structure of the ammonia-hydrogen combustion coupled ammonia decomposition hydrogen production system (II).
[0030] The markings in the figures are as follows:
[0031] 1 - liquid ammonia storage device; 2 - vaporizer; 3 - first heat exchanger, 31 - first heat exchange cold air channel, 32 - first heat exchange hot air channel; 4 - second heat exchanger, 41 - second heat exchange cold air channel, 42 - second heat exchange hot air channel; 5 - ammonia decomposition reactor, 51 - ammonia decomposition reaction ammonia channel, 52 - ammonia decomposition reaction flue gas channel; 6 - membrane separation and purification device, 61 - purified gas channel, 62 - residual gas channel; 7 - burner; 8 - air source; 9 - radiator; 10 - hydrogen collector; 20 - hydrogen tank; 30 - flue gas processor; 40 - control device. SPECIFIC EMBODIMENTS
[0032] The technical solutions of the utility model will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are some embodiments of the utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the utility model without creative efforts fall within the protection scope of the utility model.
[0033] Embodiment 1:
[0034] As Figure 1As shown in the figure, this embodiment provides a system for coupling ammonia combustion and ammonia decomposition to produce hydrogen, which includes a liquid ammonia storage device 1, a vaporizer 2, a first heat exchanger 3, a second heat exchanger 4, an ammonia decomposition reactor 5, a membrane separation and purification device 6, a radiator 9, and a hydrogen collector 10. The liquid ammonia storage device 1 is connected to the vaporizer 2 and is used to vaporize liquid ammonia into ammonia gas. The first heat exchanger 3 includes a first cold heat exchange channel 31 and a first hot heat exchange channel 32. The second heat exchanger 4 includes a second cold heat exchange channel 41 and a second hot heat exchange channel 42. The ammonia decomposition reactor 5 includes an ammonia decomposition reaction ammonia gas channel 51 and an ammonia decomposition reaction flue gas channel 52. The membrane separation and purification device 6 includes a purified gas channel 61 and a residual gas channel 62. The outlet of the vaporizer 2 is connected to the inlet of the first cold heat exchange channel 31, and the outlet of the first cold heat exchange channel 31 is connected to the inlet of the second cold heat exchange channel 41 to heat up the ammonia gas vaporized by the vaporizer 2 through the first heat exchanger 3 for the first time. The outlet of the second cold heat exchange channel 41 is connected to the inlet of the ammonia decomposition reaction ammonia gas channel 51, and the ammonia gas after heat exchange through the second heat exchanger 4 is introduced into the ammonia decomposition reactor 5 for ammonia decomposition. The outlet of the ammonia decomposition reaction ammonia gas channel 51 is connected to the inlet of the second hot heat exchange channel 42, and the outlet of the second hot heat exchange channel 42 is connected to the inlet of the purified gas channel 61. The product mixed gas decomposed by the ammonia decomposition reactor 5 is used as the heat exchange medium of the second heat exchanger 4 to exchange heat with the ammonia gas passing through the second cold heat exchange channel 41 and then introduced into the membrane separation and purification device 6 for hydrogen purification. The membrane separation and purification device 6 includes at least one inlet, two outlets, and contains a metal alloy separation membrane inside. The gas channel through which the gas entering from the inlet passes through the separation membrane and flows out from one of the outlets is the purified gas channel 61, and the gas channel through which the gas that does not pass through the separation membrane and flows out from the other outlet is the residual gas channel 62. The membrane separation and purification device 6 is separated by the metal alloy separation membrane for purification. The gas passing through the separation membrane is the purified gas, and the gas that does not pass through the separation membrane is the residual gas and enters the residual gas channel 62. The outlet of the purified gas channel 61 is sequentially connected in series with the radiator 9 and the hydrogen collector 10 for cooling and collecting the purified hydrogen.
[0035] Further, the system further includes a burner 7. The outlet of the residual gas channel 62 is communicated with the inlet of the burner 7, the outlet of the burner 7 is communicated with the inlet of the ammonia decomposition reaction flue gas channel 52, and the outlet of the ammonia decomposition reaction flue gas channel 52 is communicated with the inlet of the first heat exchange hot gas channel 32. After the high-temperature flue gas generated by the ignition and combustion of the mixed gas in the burner 7 provides heat energy for the ammonia decomposition reaction in the ammonia decomposition reactor 5, the remaining heat is used for heat exchange of ammonia gas through the first heat exchanger 3. The present utility model realizes the efficient recovery and utilization of energy through multi-stage heat exchange between the heat generated during the ammonia decomposition process and the heat generated during the combustion process. In particular, the high-temperature flue gas generated by combustion is used to preheat the ammonia gas entering the ammonia decomposition reactor, reducing energy consumption and improving the overall thermal efficiency of the system. By introducing a membrane separation and purification device, the product gas generated by ammonia decomposition is efficiently separated and purified, effectively improving the purity of hydrogen. This is particularly important for application scenarios that require high-purity hydrogen, such as fuel cells, semiconductor manufacturing, and other fields. The residual gas generated during the membrane separation and purification process (mainly unreacted ammonia and nitrogen, etc.) is sent to the burner for combustion, realizing the resource utilization of the residual gas and avoiding environmental pollution and energy waste.
[0036] The separation membrane for purification in the membrane separation and purification device 6 is a hydrogen-selective permeable membrane, which can efficiently separate hydrogen from other gases. Specifically, the separation membrane of the membrane separation and purification device 6 adopts a metal vanadium or metal niobium alloy membrane, and the alloy material can be expressed as, M1 x M2 y M3 z ; where M1 represents metal V or Nb, or both, M2 represents one or more of metals W, Mo, Ta, and M3 represents one of Cr, Mn, Ti, Al, Y, Ma, La, Sr, Ba, Ce; the subscripts x, y, z respectively represent the molar fractions corresponding to the atoms of elements M1, M2, M3, where x is 0.87 to 0.96, y is 0.03 to 0.13, z is 0.005 to 0.01, and x + y + z = 1.00; M1 and M2 form a solid solution, and the role of M3 is a deoxidizing alloying element. In this embodiment, the separation membrane in the membrane separation and purification device 6 adopts a metal vanadium niobium alloy membrane, and the specific material can be expressed as V 0.80 Nb 0.12 Mo 0.05 Cr 0.03 . The working temperature of the separation membrane is 440 °C; the working pressure is 0.7 MPa.
[0037] The ammonia decomposition reactor 5 uses a fixed-bed reactor. An ammonia decomposition catalyst is filled in the ammonia gas channel of the reactor. The reactant ammonia gas flow enters the ammonia gas channel of the reactor after flowing out of the second heat exchanger and flows through the ammonia decomposition catalyst to be converted into decomposition products to obtain hydrogen and nitrogen. The ammonia decomposition catalyst is an iron-based catalyst, which is a fused iron catalyst. After the device operates stably, the reaction conditions of the reactor are as follows: the working temperature is 550 - 580 °C; the gas pressure in the reactor is 0.7 MPa; the ammonia gas space velocity is 4500 h -1 , and the filled catalyst volume is 2.5 L.
[0038] The burner 7 is equipped with ignition equipment. At appropriate fuel flow rate and air flow rate, after successful ignition and when the device operates stably, the air flow rate is 12 times the ammonia gas flow rate flowing into the ammonia decomposition reactor; the outlet temperature of the burner remains around 750 °C.
[0039] The purified hydrogen flowing out of the membrane separation and purification device 6 in this embodiment, after analysis and measurement, has a purity of not less than 99.99%; the hydrogen production rate calculated based on this part of hydrogen can reach 67.3%.
[0040] The system further includes an air source 8, a hydrogen gas tank 20, and a flue gas processor 30. The outlets of the air source 8, the hydrogen gas tank 20, the vaporizer 2, the outlet of the second heat exchange hot gas channel 42, and the outlet of the residual gas channel 62 can be simultaneously connected to the inlet of the burner 7 to provide fuel gas and combustion-supporting gas for the burner 7. The outlet of the first heat exchange hot gas channel 32 is connected to the flue gas processor 30 for purifying the discharged flue gas.
[0041] As Figure 2 shown, the system further includes a control device 40. The control device 40 is electrically connected to the ammonia decomposition reactor 3 and the burner 7 respectively. By adjusting the ratios of hydrogen, air, and ammonia in the burner 7, the control device 40 can flexibly control the temperature and intensity of the combustion reaction, and further adjust the decomposition rate of the ammonia decomposition reaction in the ammonia decomposition reactor 3 to ensure the stable operation of the system under different working conditions.
[0042] Thoughts on improving the overall energy efficiency of the system regarding the design of the heat exchange system:
[0043] From the technical characteristics of the device and the process characteristics of the ammonia decomposition reaction, since the ammonia decomposition reaction needs to be carried out at high temperature and the reaction itself is an endothermic reaction, therefore, the heat to be provided for the stable operation of the equipment mainly includes the heat absorbed by the reaction, the heat absorbed by the vaporization of liquid ammonia, the heat required to heat gaseous ammonia from a temperature near room temperature to the reaction temperature, the heat required to maintain the temperature of the reactor and the catalyst, and the natural heat dissipation generated by the contact between the pipeline and the cavity and the outside world. Except that the vaporization of liquid ammonia can absorb heat from the environment at normal temperature and pressure, all other heat to be absorbed needs to be provided by the heat of the flue gas generated during the combustion process in the burner at the source. Combustion heating is a simple, efficient and space-saving heating method. Except for the burner itself as the heat source, the reactor requires the highest temperature. However, for simple heat exchange, the overall energy utilization rate is difficult to be satisfactory. In order to improve the energy utilization rate, the present application designs a two-stage ammonia heat exchanger, so that the higher-temperature flue gas undergoes two heat exchanges, and at the same time, the product gas also undergoes one heat exchange, and the ammonia gas before entering the reactor is preheated more fully.
[0044] The temperature and pressure matching is considered as follows: As mentioned above, the preferred operating temperature of the metal separation membrane is 400 - 500 °C, and the temperature in the reactor is preferably 450 - 580 °C. It can be seen from this that the temperature and pressure ranges of the product gas after passing through the second heat exchanger will have good matching with the operating temperature range of the metal separation membrane. Especially for the preferred reaction temperature and pressure ranges, they have good matching with the temperature and pressure ranges where the alloy membrane has good separation performance. This enables the alloy membrane to perform gas separation and purification without further process change operations such as heating and pressurizing the product gas, simplifies the process, and also saves the overall energy consumption.
[0045] An obvious common sense in this field is that the purity of hydrogen significantly affects the quality or value of germanium hydrogen products. For example, one of the requirements for the purity of hydrogen in a low-temperature hydrogen-oxygen fuel cell is that the purity is not less than 99.99%. Therefore, the hydrogen generated by chemical reactions usually requires a purification process to significantly improve the value of the hydrogen product. For the commonly used hydrogen purification methods, the relatively mature ones are mainly the metal membrane separation method and the pressure swing adsorption method (PSA) based on pressure swing adsorption technology.
[0046] The PSA method utilizes the different adsorption capacities of porous materials such as molecular sieves for different gas molecules, as well as the different changes in adsorption and desorption capacities and rates under variable pressure. Through multiple pressure swing operations, some substance molecules (usually impurity molecules) in the raw material gas are adsorbed on the porous substance while more target gas molecules are desorbed, thereby realizing the purification of the target gas. The pressure swing adsorption method is technically mature, and the gas can be purified to a high purity according to the purity requirements. Its disadvantage is that the device is too large and heavy, suitable for factory sites, and it is very difficult to be applied to mobile, skid-mounted, and modular equipment.
[0047] The metal membrane separation principle utilizes the screening effect of metal lattices on substances of different sizes and different chemical affinity capabilities at a certain temperature, enabling target gas molecules to pass through the metal membrane faster while impurity molecules cannot pass through or pass through more slowly. Its advantages are high separation efficiency per unit mass of the equipment, strong chemical selectivity, and easy miniaturization and lightweight of the device. The current main disadvantage is that there are not many types of available materials and the cost is relatively high. Especially for the currently relatively most widely used palladium metal membrane, due to the precious metal property of the material and the high processing cost, the usage cost of the palladium membrane is relatively high.
[0048] This case fully utilizes the characteristics of the working temperature and pressure of the ammonia decomposition to hydrogen production reaction, making it suitable for using non-precious metal alloy membranes for hydrogen purification. By using non-precious metal alloy membranes, compared with palladium-based membranes, the cost of the separation membrane is greatly reduced; on the other hand, compared with the commonly used pressure swing adsorption separation method, for the same hydrogen separation flux in this case, the weight and volume are greatly reduced, which is of great significance for the miniaturization, modularization, and mobility of the device.
[0049] Example 2:
[0050] Others are the same as in Example 1, and the main differences are as follows:
[0051] In this embodiment, the separation membrane in the membrane separation purifier 6 adopts a metal vanadium niobium alloy membrane, and the specific material can be expressed as V 0.86 Nb 0.08 Mo 0.03 Ti 0.03 .
[0052] The working temperature of the separation membrane is 390 °C; the working pressure is 0.85 MPa.
[0053] The ammonia decomposition catalyst is a ruthenium-based catalyst, which is a ruthenium catalyst supported on alumina, and the loading amount of ruthenium is 1.5 wt%; after the device runs stably, the reaction conditions of the reactor are as follows: the working temperature is 500 °C; the gas pressure in the reactor is 0.85 MPa; the ammonia gas space velocity is 3000 h -1 , and the volume of the filled catalyst is 2.5 L.
[0054] The burner 7 contains ignition equipment. At appropriate fuel flow rate and air flow rate, after successful ignition and when the device runs stably, the air flow rate is 7 times the ammonia gas flow rate flowing into the ammonia decomposition reactor; the temperature at the burner outlet remains near 720 °C.
[0055] The purified hydrogen flowing out of the membrane separation purifier 6 in this embodiment, after analysis and measurement, its purity is not less than 99.99%; calculated based on this part of hydrogen, the hydrogen production rate can reach 75.8%.
[0056] The system of the present utility model is designed to be compact, and each unit is closely connected through effective management of heat exchange and air flow, achieving a high degree of integration in the hydrogen production process. This not only reduces the floor area of the equipment, but also simplifies the operation process, reduces the complexity of the system and the maintenance cost.
[0057] Where the present utility model is not described, it shall be applicable to the prior art.
[0058] Obviously, the above embodiments are merely examples given for clear illustration, rather than limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present utility model.
Claims
1. An ammonia-hydrogen combustion coupled with ammonia decomposition hydrogen production system, characterized in that: The invention comprises a liquid ammonia storage device (1), a vaporizer (2), a second heat exchanger (4), an ammonia decomposition reactor (5), a membrane separation purifier (6), a radiator (9) and a hydrogen collector (10); the liquid ammonia storage device (1) is connected to the vaporizer (2) and is used to gasify liquid ammonia into ammonia gas; the second heat exchanger (4) comprises a second heat exchange cold air channel (41) and a second heat exchange hot air channel (42); the ammonia decomposition reactor (5) comprises an ammonia decomposition reaction ammonia channel (51) and an ammonia decomposition reaction flue gas channel (52); the membrane separation purifier (6) comprises a purified gas channel (61) and a residual gas channel (62); the outlet of the vaporizer (2) is connected to the inlet of the second heat exchange cold air channel (41); the outlet of the second heat exchange cold air channel (41) is connected to the ammonia decomposition reaction channel (51); the outlet of the second heat exchange cold air channel (41) is connected to the ammonia decomposition reaction channel (52); The inlet of the decomposition reaction ammonia channel (51) is connected, and the ammonia after heat exchange in the second heat exchanger (4) is introduced into the ammonia decomposition reactor (5) for ammonia decomposition; the outlet of the ammonia decomposition reaction ammonia channel (51) is connected with the inlet of the second heat exchange hot gas channel (42), and the outlet of the second heat exchange hot gas channel (42) is connected with the inlet of the purified gas channel (61), and the product mixed gas after decomposition in the ammonia decomposition reactor (5) is used as the heat exchange medium of the second heat exchanger (4) and the ammonia after heat exchange in the second heat exchange cold gas channel (41) and then introduced into the membrane separation purifier (6) for hydrogen purification; the outlet of the purified gas channel (61) is connected in series with the radiator (9) and the hydrogen collector (10) in sequence, so as to cool and collect the purified hydrogen.
2. The ammonia-hydrogen combustion coupled with ammonia decomposition hydrogen production system according to claim 1, characterized in that: The system further comprises a first heat exchanger (3) and a burner (7); the first heat exchanger (3) comprises a first heat exchange cold air channel (31) and a first heat exchange hot air channel (32); the outlet of the vaporizer (2) is connected to the inlet of the first heat exchange cold air channel (31); the outlet of the first heat exchange cold air channel (31) is connected to the second heat exchange cold air channel (41); the ammonia gas vaporized by the vaporizer (2) is subjected to a first heat exchange and temperature increase through the first heat exchanger (3); the residual gas The outlet of the channel (62) is connected to the inlet of the burner (7), the outlet of the burner (7) is connected to the inlet of the ammonia decomposition reaction flue gas channel (52), the outlet of the ammonia decomposition reaction flue gas channel (52) is connected to the inlet of the first heat exchange hot gas channel (32), and the high-temperature flue gas generated by the ignition and combustion of the mixed gas in the burner (7) provides heat energy for the ammonia decomposition reaction in the ammonia decomposition reactor (5), and the remaining heat is used for heat exchange of ammonia through the first heat exchanger (3).
3. The ammonia-hydrogen combustion coupled with ammonia decomposition hydrogen production system according to claim 2, characterized in that: The separation membrane used for purification in the membrane separation purifier (6) is a selective hydrogen permeable membrane, which can efficiently separate hydrogen from other gases.
4. The ammonia-hydrogen combustion coupled with ammonia decomposition hydrogen production system according to claim 1, characterized in that: The ammonia decomposition reactor (5) is a fixed bed reactor. An ammonia decomposition catalyst is filled in the ammonia channel of the ammonia decomposition reactor (5). The reactant ammonia gas flow flows out of the second heat exchanger (4) and enters the ammonia channel of the ammonia decomposition reactor (5), flows through the ammonia decomposition catalyst, and is converted into decomposition products to obtain hydrogen and nitrogen.
5. The ammonia-hydrogen combustion coupled with ammonia decomposition hydrogen production system according to claim 3, characterized in that: The system further comprises an air source (8), a hydrogen tank (20) and a flue gas processor (30); the air source (8), the hydrogen tank (20), the outlet of the gasifier (2), the outlet of the second heat exchange hot gas channel (42) and the outlet of the residual gas channel (62) can be simultaneously connected to the inlet of the burner (7) to provide fuel gas and combustion-supporting gas for the burner (7); the outlet of the first heat exchange hot gas channel (32) is connected to the flue gas processor (30) to purify the exhausted flue gas.
6. The ammonia-hydrogen combustion coupled with ammonia decomposition hydrogen production system according to any one of claims 1 to 5, characterized in that: The system further comprises a control device (40), wherein the control device (40) is electrically connected to the ammonia decomposition reactor (3) and the burner (7), respectively. The control device (40) can flexibly control the temperature and intensity of the combustion reaction by adjusting the ratio of hydrogen, air and ammonia in the burner (7), thereby adjusting the decomposition rate of the ammonia decomposition reaction in the ammonia decomposition reactor (3).