Solid oxide electrolytic cell, solid oxide electrolytic reactor and method and system for preparing ammonia and fuel by using solid oxide electrolytic cell and solid oxide electrolytic reactor

Abstract

The invention discloses a solid oxide electrolytic cell, a solid oxide electrolytic reactor and a method and system for preparing ammonia and fuel by using the solid oxide electrolytic cell and the solid oxide electrolytic reactor. The solid oxide electrolytic cell comprises an anode, an electrolyte and a cathode, the cathode inputs mixed gas composed of air or nitrogen and water vapor, electrochemical deoxidation reaction is carried out, and ammonia feed gas containing hydrogen and nitrogen is generated; the anode inputs mixed gas composed of combustible gas, water vapor and / or carbon dioxide, the mixed gas and oxygen ions transmitted from the cathode to the anode are subjected to partial oxidation reaction, and synthesis gas containing hydrogen, carbon monoxide and carbon dioxide is generated. The solid oxide electrolysis reactor comprises an anode end plate, an intermediate plate assembly and a cathode end plate which are connected in sequence; the intermediate plate assembly includes a number of repeating units. The electrolytic deoxidation reaction and the partial oxidation reaction of the combustible gas are coupled, so that the electrolytic power consumption is greatly reduced, the low-cost green preparation of the raw material gas for synthesizing ammonia and synthetic fuel is realized, and the production cost of green ammonia and green synthetic fuel is further reduced.

Description

Technical Field

[0001] The present invention relates to an electrolytic cell and a preparation method and application thereof, and specifically to a solid oxide electrolytic cell, a solid oxide electrolytic stack and a method and system for preparing ammonia and fuel therefrom. Background Art

[0002] Hydrogen production by water electrolysis is the main method for producing green hydrogen. Alkaline electrolysis (ALK) and proton exchange membrane electrolysis (PEM) are relatively mature water electrolysis technologies. The operating temperature does not exceed 90°C, and the electrolysis power consumption per kilogram of hydrogen is about 54kWh and 52kWh respectively. Solid oxide electrolysis cell (SOEC) is an emerging high-temperature water electrolysis hydrogen production technology. Most of them use oxygen ion conductive oxides (such as yttria-stabilized zirconia, etc.) as electrolyte diaphragms. The operating temperature is generally 400-850°C. High-temperature operation reduces the electrolysis power consumption per kilogram of hydrogen to 37.5-46kWh.

[0003] Using electricity generated by clean energy such as solar energy and wind energy to electrolyze water to produce hydrogen can not only achieve sustainable production of hydrogen, but also promote the large-scale consumption of intermittent renewable energy. However, the high power consumption of hydrogen electrolysis, the misalignment of hydrogen production and use, and the high cost of hydrogen storage and transportation have severely restricted the large-scale application of green hydrogen. Methanol and ammonia are important chemical products and raw materials that are widely used. Both production raw materials include hydrogen. In 2022, global hydrogen demand will be 94 million tons, of which 32 million tons will be used for synthetic ammonia and 16 million tons will be used for methanol production. On the other hand, methanol and ammonia can be converted into hydrogen through catalytic reforming or cracking reactions, and are expected to become ideal hydrogen storage carriers.

[0004] Green hydrogen is produced by electrolyzing water using renewable energy, and then combined with nitrogen separated from the air through the Haber-Bosch and other synthetic ammonia processes to obtain green ammonia; green hydrogen can also be synthesized with carbon dioxide under high temperature and high pressure to obtain green or low-carbon methanol. Methanol is a liquid at room temperature, ammonia is easy to liquefy, easy to store and transport, and has mature production and utilization technologies. Therefore, ammonia and methanol can be used as new green fuels and raw materials to promote the storage and utilization of hydrogen energy, and achieve carbon reduction and emission reduction in transportation, power supply and other fields.

[0005] The Haber-Bosch ammonia synthesis reaction and the carbon dioxide hydrogenation reaction are very mature. However, the cost of hydrogen production by water electrolysis is currently relatively high, which also leads to high production costs of green ammonia and low-carbon methanol. Therefore, the high cost of green hydrogen has become the main factor affecting the large-scale application of green ammonia and low-carbon methanol. There is an urgent need to develop low-cost preparation technologies for green ammonia and low-carbon methanol based on green hydrogen, especially low-cost preparation technologies for nitrogen-hydrogen feed gas and synthesis gas.

[0006] US20230193486A1 proposes a device for producing synthetic ammonia raw gas. By configuring an electrically driven air separation unit and a solid oxide electrolysis cell, the heat generated by the electrically driven air separation unit is transferred to the solid oxide electrolysis cell, thereby realizing the integration of the electrically driven air separation unit nitrogen production and the solid oxide electrolysis cell hydrogen production unit. The conversion rate of the reactants is improved by increasing the current and the operating power of the electrolysis stack, thereby simplifying the auxiliary system design and reducing the system manufacturing and operating costs.

[0007] ZA202001001B feeds a mixture of steam and air into the first of a series of SOEC electrolyzers, and passes the outlet of one SOEC electrolyzer together with air to the inlet of the next SOEC electrolyzer, the SOEC electrolyzer operates in endothermic mode, and the nitrogen in the raw gas is provided by burning hydrogen produced by steam electrolysis with air in the SOEC electrolyzer or between the SOEC electrolyzers, thereby obtaining synthetic ammonia raw gas.

[0008] CN116601335A obtains CO and CO by electrolyzing carbon dioxide 2 The feed stream is obtained by electrolysis of water containing H 2 The two feed streams are combined into synthesis gas, which is then converted into methanol or hydrocarbon products. US20240059562A1 combines a SOEC electrolysis stack with an electrically heated water gas reformer to produce synthesis gas rich in carbon monoxide.

[0009] However, the preparation of ammonia raw gas or synthesis gas described in the above patents is a series-parallel combination of a high-temperature water electrolysis hydrogen production module and a high-temperature carbon dioxide electrolysis carbon monoxide production module. It is well known that the power consumption of high-temperature water electrolysis hydrogen production or high-temperature carbon dioxide electrolysis carbon monoxide production is still very high, resulting in high costs for the production of ammonia raw gas and synthesis gas. Summary of the invention

[0010] Purpose of the invention: In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a solid oxide electrolysis cell for the co-production of synthetic ammonia raw gas and synthesis gas which reduces the power consumption of electrolysis. Another purpose of the present invention is to provide a solid oxide electrolysis stack which reduces the power consumption of electrolysis. Another purpose of the present invention is to provide a low-cost, green and environmentally friendly method for preparing ammonia and fuel. Another purpose of the present invention is to provide an energy-saving and controllable system for preparing ammonia and fuel.

[0011] Technical solution: The solid oxide electrolytic cell for co-producing synthetic ammonia raw gas and synthesis gas described in the present invention comprises an anode, an electrolyte and a cathode; the anode and the cathode are made of a porous composite ceramic comprising an electronic conductive phase and an oxygen ion conductive phase, the volume fraction of the electronic conductive phase is not less than 40%, and the porosity of the porous composite ceramic is 5-95%; the cathode inputs a cathode mixed gas consisting of air or nitrogen and water vapor, and undergoes an electrochemical deoxidation reaction to generate a synthetic ammonia raw gas consisting of hydrogen and nitrogen; the anode inputs an anode mixed gas consisting of combustible gas, water vapor and / or carbon dioxide, and undergoes a partial oxidation reaction with oxygen ions generated by the cathode deoxidation reaction and transmitted to the anode to generate a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide.

[0012] Furthermore, the electrolyte is one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, doped cerium oxide, strontium magnesium-doped lanthanum gallate, doped barium zirconate, and doped barium ceria.

[0013] Furthermore, the electronically conductive phase is Ni, Cu, 430L, (La 1-x Sr x )(Cr 1-y Fe y ) 3-δ , (La 1-x Sr x )(Cr 1- y Mn y ) 3-δ ,La 2-x Sr x Fe 2-y-z Ni y Mo z O 6-δ 、430L-(La 1-x Sr x )(Cr 1-y Fe y ) 3-δ One or more of the following, wherein 0<x<1, 0<y<1, 0<δ<1; the oxygen ion conductive phase is one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, doped cerium oxide, strontium magnesium-doped lanthanum gallate, doped barium zirconate, and doped barium ceria.

[0014] Furthermore, the inner wall of the porous composite ceramic is covered with a nanocatalyst, and the nanocatalyst is Ni, Fe, Co, FeNi 3 、Ce 1-x Sm x O 2-δ 、Ce 1-x G x O 2-δ , (La 1-x Srx )(Co 1-y Fe y ) 3-δ 、(Ba 1-x Sr x )(Co 1-y Fe y ) 3-δ 、(Sm 1- x Sr x )CoO 3-δ 、SmBaCo 2 O 5+δ 、LaBa 0.5 Sr 0.5 Co 2 O 5+δ 、SmBa 0.5 Sr 0.5 Co 2 O 5+δ ,BaGd 0.8 La 0.2 Co 2 O 6-δ ,La 2- x Sr x Fe 2-y-z Ni y Mo z O 6-δ One or more of, wherein 0<x<1, 0<y<1, 0<δ<1.

[0015] Further, the operating temperature range of the solid oxide electrolytic cell is 300-1000°C, and the electrolysis voltage between the cathode and the anode is 0.1-2.0 V. Preferably, the operating temperature range of the solid oxide electrolytic cell is 500-750°C, and the electrolysis voltage between the cathode and the anode is 0.3-1.3 V.

[0016] A solid oxide electrolytic stack described in the present invention comprises an anode terminal plate, an intermediate plate assembly and a cathode terminal plate connected in sequence, wherein the intermediate plate assembly comprises a plurality of repeating units, and connecting plates are arranged between the repeating units; the repeating units comprise an anode seal, an anode current collector, an electrolytic cell, a middle frame, a cathode current collector and a cathode seal, wherein the anode seal, the middle frame and the cathode seal are all hollow frames, the anode seal and the electrolytic cell, the middle frame, the connecting plate or the anode terminal plate form an anode chamber, the anode current collector is arranged in the anode chamber, the cathode seal and the electrolytic cell, the middle frame, the connecting plate or the cathode terminal plate form a cathode chamber, the cathode current collector is arranged in the cathode chamber, and the anode chamber and the cathode chamber are isolated from each other; the electrolytic cell comprises an anode, an electrolyte and a cathode; the anode and the cathode are made of a porous composite ceramic comprising an electronic conductive phase and an oxygen ion conductive phase, wherein the volume fraction of the electronic conductive phase is not less than 40%, and the porosity of the porous composite ceramic is 5-95%.

[0017] Furthermore, an anode raw gas inlet is arranged on one side of the cathode end plate and the middle plate assembly, and a cathode raw gas inlet is arranged on the other side; an anode raw gas outlet is arranged on one side of the anode end plate and the middle plate assembly, and a cathode raw gas outlet is arranged on the other side; the anode raw gas inlet is connected to the anode raw gas outlet through the anode chamber, and the cathode raw gas inlet is connected to the cathode raw gas outlet through the cathode chamber.

[0018] Furthermore, the anode current collector and the cathode current collector are made of nickel foam, nickel felt, nickel mesh, copper foam, copper felt, copper mesh, stainless steel mesh, porous (La 1-x Sr x )TiO 3–δ 、Porous La 2-x Sr x Fe 2-y-z Ni y Mo z O 6-δ Made of one or more materials.

[0019] Furthermore, the top surface of the anode current collector is in close contact with the bottom surface of the anode end plate or the bottom surface of the connecting plate, and the bottom surface of the anode current collector is in close contact with the anode of the electrolytic cell; the top surface of the cathode current collector is in close contact with the cathode of the electrolytic cell, and the bottom surface of the cathode current collector is in close contact with the top surface of the cathode end plate or the top surface of the connecting plate.

[0020] Furthermore, the anode end plate, the middle frame, the connecting plate and the cathode end plate are high temperature alloys or conductive oxides with a thermal expansion coefficient close to that of the electrolyte, preferably 430L, 441, 446, Crofer, (La 1-x Sr x )TiO 3–δ ,La 2-x Sr x Fe 2-y-z Ni y Mo z O 6-δ One or more of, wherein 0<x<1, 0<y<1, 0<δ<1.

[0021] The method for preparing ammonia and fuel by a solid oxide electrolytic stack described in the present invention comprises the following steps: inputting a cathode mixed gas consisting of air or nitrogen and water vapor into the cathode, and causing an electrochemical deoxidation reaction in the cathode chamber to generate a synthetic ammonia raw gas consisting of hydrogen and nitrogen; inputting an anode mixed gas of one or more of combustible gas, water vapor and / or carbon dioxide into the anode, and causing a partial oxidation reaction in the anode chamber with oxygen ions generated by the cathode deoxidation reaction and transmitted to the anode to generate a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide, and then converting the synthesis gas containing hydrogen, carbon monoxide and carbon dioxide into synthetic fuel.

[0022] The system for preparing ammonia and fuel described in the present invention comprises a raw material supply control module, a solid oxide electrolysis module, a process gas storage and pressurization module, a synthetic ammonia module, a synthetic fuel module and a control module connected in sequence, wherein the raw material supply control module is used to control the composition and flow rate of the cathode mixed gas and the anode mixed gas; the solid oxide electrolysis module comprises one or more of the above-mentioned solid oxide electrolysis stacks, ejectors, heat exchangers, heaters, and condensers, and is used to generate synthetic ammonia raw gas and synthetic gas containing hydrogen and carbon; the process gas storage and pressurization module is used to pressurize the ammonia raw gas and the synthetic gas containing hydrogen, carbon monoxide and carbon dioxide and output them to the synthetic ammonia module and the synthetic fuel module respectively. The synthetic ammonia module includes but is not limited to components such as a synthetic ammonia reactor, a heat exchanger, and a separation tank. The synthetic fuel module includes but is not limited to components such as a synthetic fuel reactor, a heat exchanger, a gas-liquid separator, a circulating gas compressor, and a synthetic fuel purification unit

[0023] Furthermore, the combustible gas is one or more of methane, ethane, propane, methanol, ethanol, hydrogen, carbon monoxide, and biomass gasification gas.

[0024] Furthermore, the heat exchangers in the solid oxide electrolysis module, the synthetic ammonia module and the synthetic fuel module are coupled to improve the energy efficiency of the system.

[0025] Furthermore, the purge gas from the synthetic ammonia module and the synthetic fuel module is circulated to the solid oxide electrolysis module to improve the raw material utilization and system energy efficiency.

[0026] Working principle: The cathode gas mixture is a mixture of water vapor and air, and the anode gas mixture is a mixture of combustible gas (taking methane as an example) and water vapor. The anode gas mixture is in a thermodynamically or kinetically stable range and will not undergo cracking or carbon deposition.

[0027] Driven by an external electric field and catalytically acted on the cathode, oxygen in the air first undergoes an oxygen reduction reaction at a relatively low voltage, namely, reaction formula (1):

[0028] O 2 (c) + 4e - → 2O 2- (c) (1)

[0029] When the oxygen in the mixed gas is exhausted, the water vapor decomposes into hydrogen and oxygen ions at a higher voltage, namely:

[0030] H 2 O (c) + 2e - → H 2 (c) + O 2- (c) (2)

[0031] Driven by an external electric field, oxygen ions are transported from the cathode side of the electrolyte diaphragm to the anode side, that is:

[0032] O 2- (c) → O 2- (a) (3)

[0033] The methane on the anode side undergoes partial oxidation reaction (4) or (5) with the oxygen ions generated by the electrolysis of water at the cathode and transferred to the anode, that is:

[0034] CH 4 (a)+O 2- (a) →2H 2 (a)+CO(a)+2e - (4)

[0035] CH 4 (a)+2O 2- (a) →2H 2 (a) +CO 2 (a)+4e - (5)

[0036] By precisely controlling the composition and flow of the cathode mixed gas and the anode mixed gas as well as the electrolysis current, the synthetic ammonia raw gas can be made mainly a mixture of nitrogen and hydrogen, while the anode product gas can be condensed to obtain a synthesis gas mainly composed of hydrogen, carbon monoxide and carbon dioxide, which are used as raw gases for synthetic ammonia and synthetic fuels respectively.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following significant characteristics: coupling the electrolytic deoxidation reaction with the partial oxidation reaction of the combustible gas not only greatly reduces the power consumption of electrolysis, but also realizes the low-cost green preparation of the raw gas for synthetic ammonia and synthetic fuel, thereby reducing the production cost of green ammonia and green synthetic fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the principle of the solid oxide electrolytic cell of the present invention;

[0039] Figure 2 It is a schematic diagram of the structure of the solid oxide electrolytic stack of the present invention;

[0040] Figure 3 is a schematic diagram of the structure of the repeating unit 51 of the present invention;

[0041] Figure 4 The figure is a flow chart of the system for preparing ammonia and fuel according to the present invention. DETAILED DESCRIPTION

[0042] The materials, reagents, instruments, etc. used in the following examples are all commercially available unless otherwise specified. Experimental methods without specific conditions specified in the examples are usually carried out under conventional conditions or under conditions recommended by the manufacturer. In the following examples, 0<x<1, 0<y<1, 0<δ<1.

[0043] Example 1

[0044] like Figure 1 The solid oxide electrolytic cell 513 includes an anode 1, an electrolyte 2 and a cathode 3 sintered from top to bottom. The electrolyte 2 is a ceramic material with oxygen ion conductivity, which is scandium oxide stabilized zirconia (ScSZ), and the diaphragm thickness is 15μm. Both the cathode 3 and the anode 1 are porous composite ceramics composed of an electronic conductive phase and an oxygen ion conductive phase, and the volume fraction of the electronic conductive phase in the solid phase is not less than 40vol%. Both the cathode 3 and the anode 1 are porous materials, which are LSCrF-ScSZ (LSCrF=La 0.8 Sr 0.2 Cr 0.5 Fe 0.5 O 3-δ ), the weight ratio of LSCrF to ScSZ is 60:40, the thickness of the anode 1 and the cathode 3 are both 0.5 mm, and the porosity is 50%. The electronic conductive phase is La 0.8 Sr 0.2 Cr 0.5 Fe 0.5 O 3-δ The oxygen ion conducting phase is scandium oxide stabilized zirconia (ScSZ). The inner walls of the pores of the cathode 3 and the anode 1 are covered with nano-La 0.3 Sr 1.55 Fe 1.5 Ni 0.1 Mo 0.4 O 6-δ(LSFNM) catalyst material, impregnation amount is 15%. The length and width of the electrolytic cell are 130mm×130mm.

[0045] The cathode 3 of the solid oxide electrolysis cell 513 inputs a cathode mixed gas 13 composed of air and water vapor (volume ratio of 7:3), and the anode 1 inputs an anode mixed gas 15 composed of water vapor and methane (volume ratio of 2:1). The anode raw gas 15 is in a thermodynamically or kinetically stable range, and methane cracking and carbon deposition will not occur. The operating temperature of the solid oxide electrolysis cell is 627°C. The electrolysis voltage between the cathode 3 and the anode 1 of the solid oxide electrolysis cell is 0.97V.

[0046] The overall deoxygenation reaction at cathode 3 is:

[0047] 0.3(0.781N 2 (c)+0.209O 2 (c))+0.7H 2 O(c)+1.6508e -

[0048] →0.2343N 2 (c)+0.7H 2 (c)+0.8254O 2- (c) (6)

[0049] The methane partial oxidation reaction at anode 1 is:

[0050] 0.8254CH 4 (a)+0.8254O 2- (a)

[0051] →0.8254CO(a)+1.6508H 2 (a)+1.6508e - (7)

[0052] The overall reaction of the electrolytic cell is:

[0053] 0.3(0.781N 2 (c)+0.209O 2 (c))+0.7H 2 O(c)+0.8254CH 4 (a)

[0054] →0.2343N 2 (c)+0.7H 2 (c)+0.8254CO(a)+1.6508H 2 (a) (8)

[0055] The thermodynamic enthalpy change of the electrolysis reaction at 627°C is 154.26 kJ / mol, the corresponding thermoneutral electrolysis voltage is 0.969 V, and the theoretical power consumption of ammonia raw gas and synthesis gas is 0.56 kWh / Nm 3 .

[0056] Example 2

[0057] The rest of the structure of this embodiment is the same as that of Embodiment 1, with the only difference being that the anode mixed gas 15 is coke oven gas, mainly including hydrogen, methane, carbon monoxide, nitrogen, and carbon dioxide, with a volume ratio of 56:27:5:8:4; the operating temperature of the electrolytic cell is 600°C, and the electrolysis voltage is 0.53V.

[0058] The overall deoxygenation reaction at cathode 3 is:

[0059] 0.2145(0.781N 2 (c)+0.209O 2 (c))+0.5H 2 O(c)+1.18e -

[0060] →0.1675N 2 (c)+0.5H 2 (c)+0.59O 2- (c) (9)

[0061] The partial oxidation reaction of the combustible gas at anode 1 is:

[0062] 0.56H 2 (a)+0.27CH 2 (a)+0.05CO(a)+0.59O 2- (a)

[0063] →0.32CO 2 (a) +1.1H 2 (a)+1.18e - (10)

[0064] The overall reaction of the electrolytic cell is:

[0065] 0.2145(0.781N 2 (c)+0.209O 2 (c))+0.5H 2 O(c)

[0066] +0.56H 2 (a)+0.27CH 4 (a)+0.05CO(a)

[0067] →0.1675N 2(c)+0.5H 2 (c)+0.32CO 2 (a) +1.1H 2 (a) (11)

[0068] The thermodynamic enthalpy change of the electrolysis reaction at 600°C is 26.19 kJ / mol, the corresponding thermoneutral electrolysis voltage is 0.23 V, and the theoretical power consumption of ammonia raw gas and synthesis gas is 0.16 kWh / Nm 3 .

[0069] Example 3

[0070] The remaining structures of this embodiment are the same as those of the embodiment 1, except that the electrolyte 2 is yttria-stabilized zirconia (YSZ), the anode 1 and the cathode 3 are both NiO-YSZ metal ceramics, the weight ratio of NiO to YSZ is 55:45, the thickness of the anode 1 and the cathode 3 are both 0.2 mm, and the porosity is both 40%. The inner walls of the anode 1 and the cathode 3 are impregnated with nano nickel oxide and cerium oxide catalysts, and the impregnation amount is 5%.

[0071] The cathode mixed gas 13 is a mixed gas of water vapor and nitrogen, and the volume ratio of water vapor to nitrogen is 75:25. The anode mixed gas 15 is a mixed gas of methane and water vapor, and the volume ratio of water vapor to methane is 2:1. The operating temperature of the electrolytic cell is 627°C, the electrolysis voltage is 1.17V, and the overall deoxygenation reaction of the cathode 3 is:

[0072] 0.25N 2 (c)+0.75H 2 O(c)+1.5e - →0.25N 2 (c)+0.75H 2 (c)+0.75O 2- (c) (12)

[0073] The partial oxidation reaction of methane at anode 1 is:

[0074] 0.75CH 4 (a) +0.75O 2- (a)→0.75CO(a)+1.5H 2 (a)+1.5e - (13)

[0075] The overall reaction of the electrolytic cell is:

[0076] 0.25N 2 (c)+0.75H 2 O(c)+0.75CH 4 (a)

[0077] →0.25N2 (c)+0.75H 2 (c)+0.75CO(a)+1.5H 2 (a) (14)

[0078] The thermodynamic enthalpy change of the electrolysis reaction at 627°C is 168.34 kJ / mol, the corresponding thermoneutral electrolysis voltage is 1.163 V, and the theoretical power consumption of ammonia raw gas and synthesis gas is 0.64 kWh / Nm 3 .

[0079] Example 4

[0080] The remaining structures of this embodiment are the same as those of the embodiment 1, except that the cathode mixed gas 13 is a mixed gas of water vapor and nitrogen, the volume ratio of water vapor to nitrogen is 75:25, and the anode mixed gas 15 is a mixed gas of methane and water vapor, the volume ratio of water vapor to methane is 2:1. The operating temperature of the electrolytic cell is 627°C, the electrolysis voltage is 0.49V, and the overall deoxygenation reaction of the cathode 3 is:

[0081] 0.5N 2 (c)+1.5H 2 O(c)+3e - →0.5N 2 (c)+1.5H 2 (c)+1.5O 2- (c) (15)

[0082] The partial oxidation reaction of methane at the anode is:

[0083] 0.75CH 4 (a) +1.5O 2- (a)→0.75CO 2 (a) +1.5H 2 (a)+3e - (16)

[0084] The overall reaction of the electrolytic cell is:

[0085] 0.5N 2 (c)+1.5H 2 O(c)+0.75CH 4 (a)

[0086] →0.5N 2 (c)+1.5H 2 (c)+0.75CO 2 (a) +1.5H 2 (a) (17)

[0087] The thermodynamic enthalpy change of the electrolysis reaction at 627°C is 141.54 kJ / mol, the corresponding thermoneutral electrolysis voltage is 0.489 V, and the theoretical power consumption of ammonia raw gas and synthesis gas is 0.59 kWh / Nm 3 .

[0088] Example 5

[0089] like Figure 2 As shown, the solid oxide electrolytic stack includes an anode end plate 4, an intermediate plate assembly 5 and a cathode end plate 6. The anode end plate 4 is the top surface of the electrolytic stack 5, the cathode end plate 6 is the bottom surface of the electrolytic stack, and the intermediate plate assembly 5 includes a plurality of repeating units 51, and each repeating unit 51 is connected by a connecting plate 52.

[0090] like Figure 3 As shown, the repeating unit 51 includes an anode seal 511, an anode current collector 512, an electrolytic cell 513, a middle frame 514, a cathode current collector 515 and a cathode seal 516 which are packaged in sequence, wherein the anode seal 511, the middle frame 514 and the cathode seal 516 are all hollow frames. The anode seal 511 seals the electrolytic cell 513, the anode current collector 512 and the middle frame 514 on the connecting plate 52, and the cathode seal 516 seals the electrolytic cell 513, the cathode current collector 515 and the middle frame 514 on the connecting plate 52. The anode seal 511 encloses the anode chamber 7 through the middle frame 514, the electrolytic cell 513, the connecting plate 52 or the anode end plate 4. The cathode seal 516 encloses the cathode chamber 8 through the middle frame 514, the electrolytic cell 513, the connecting plate 52 or the cathode end plate 6, and the anode chamber 7 is isolated from the cathode chamber 8. The anode end plate 4, the middle frame 514, the connecting plate 52 and the cathode end plate 6 are made of high temperature alloy 446 having a thermal expansion coefficient close to that of the electrolyte 2. The surfaces of the anode end plate 4, the connecting plate 52 and the cathode end plate 6 are covered with a conductive protective coating FeNi 3 The anode current collector 512 and the cathode current collector 515 are nickel foam metals with high porosity and good electronic conductivity. The anode seal 511 and the cathode seal 516 are high temperature sealing glass with high resistivity.

[0091] The anode current collector 512 is filled in the anode chamber 7, the top surface of the anode current collector 515 is in close contact with the bottom surface of the anode terminal plate 4 or the bottom surface of the connecting plate 52, and the bottom surface of the anode current collector 515 is in close contact with the anode 1 of the electrolytic cell 513. The cathode current collector 515 is filled in the cathode chamber 8, the top surface of the cathode current collector 515 is in close contact with the cathode 3 of the electrolytic cell 513, and the bottom surface of the cathode current collector 515 is in close contact with the top surface of the cathode terminal plate 6 or the top surface of the connecting plate 52.

[0092] The cathode end plate 6, the repeating unit 51 and the connecting plate 52 are each provided with at least one anode raw material gas inlet 9 on one side, and at least one cathode raw material gas inlet 10 on the other side. The anode end plate 4, the repeating unit 51 and the connecting plate 52 are each provided with at least one anode raw material gas outlet 11 on one side, and at least one cathode raw material gas outlet 12 on the other side. The anode raw material gas inlet 9 is connected to the anode raw material gas outlet 11 through the anode chamber 7, and the cathode raw material gas inlet 10 is connected to the cathode raw material gas outlet 12 through the cathode chamber 8.

[0093] The cathode mixed gas 13 is a mixed gas composed of air or nitrogen and water vapor, which enters the cathode chamber 8 of the electrolytic stack through the cathode raw gas inlet 12, and an electrochemical deoxygenation reaction occurs on the cathode 3 of the electrolytic cell 513, including but not limited to oxygen reduction reaction and water electrolysis reaction, to generate a synthetic ammonia raw gas 14 mainly composed of hydrogen and nitrogen, and leaves the electrolytic stack from the cathode raw gas outlet 12.

[0094] The anode mixed gas 15 is a mixed gas composed of combustible gas, water vapor, carbon dioxide, etc., which enters the anode chamber 7 of the electrolytic stack through the anode raw gas inlet 9, and under the catalytic action of the anode 1 of the electrolytic cell, it undergoes a partial oxidation reaction with the oxygen ions generated by the deoxidation reaction of the cathode 3 and transmitted to the anode 1, generating a synthesis gas 16 containing hydrogen, carbon monoxide and carbon dioxide, and leaves the electrolytic stack from the anode raw gas outlet 11. The combustible gas in the anode mixed gas 15 includes, but is not limited to, methane, ethane, propane, methanol, ethanol, hydrogen, carbon monoxide, etc.

[0095] Example 6

[0096] like Figure 4 As shown, the co-production system includes a raw material supply control module, a solid oxide electrolysis module (including a solid oxide electrolysis stack of Example 5), a process gas storage and boosting module, a synthetic ammonia module, a synthetic fuel module and a control module, etc. The solid oxide electrolysis module includes but is not limited to a solid oxide electrolysis stack, an ejector, a heat exchanger, a heater, a condenser, etc., the synthetic ammonia module includes but is not limited to a synthetic ammonia reactor, a heat exchanger, a separation tank, etc., and the synthetic fuel module includes but is not limited to a synthetic fuel reactor, a heat exchanger, a gas-liquid separator, a circulating gas compressor, a synthetic fuel purification unit, etc.

[0097] The raw material supply control module is used to control the composition and flow of air or nitrogen and water vapor mixed gas A and combustible gas, carbon dioxide, water vapor mixed gas B. Mixed gas A and mixed gas B enter the solid oxide electrolysis module, and after being fully preheated, enter the solid oxide electrolysis stack, and are coupled with the partial oxidation reaction of the combustible gas through electrolytic deoxidation, and are synchronously converted into nitrogen-hydrogen mixed gas and synthesis gas respectively.

[0098] After being fully cooled, the nitrogen-hydrogen mixture and the synthesis gas enter the process gas storage and pressurization module, and then after being pressurized, they enter the synthetic ammonia module and the synthetic fuel module respectively. The nitrogen-hydrogen mixture is converted into ammonia in the synthetic ammonia reactor, and after being fully cooled, liquid ammonia is obtained. The synthesis gas is converted into synthetic fuel in the fuel reactor, and after cooling, gas-liquid separation and purification, synthetic fuel is obtained.

[0099] The heat exchangers in the solid oxide electrolysis module, the synthetic ammonia module and the synthetic fuel module are coupled to improve the system energy efficiency. The purge gas of the synthetic ammonia module and the synthetic fuel module is circulated to the solid oxide electrolysis module to improve the raw material utilization and system energy efficiency.

Claims

1. A solid oxide electrolysis cell for co-producing synthetic ammonia feed gas and synthesis gas, characterized in that: The invention comprises an anode (1), an electrolyte (2) and a cathode (3); the anode (1) and the cathode (3) are made of a porous composite ceramic comprising an electronic conductive phase and an oxygen ion conductive phase, the volume fraction of the electronic conductive phase is not less than 40%, and the porosity of the porous composite ceramic is 5-95%; the cathode (3) inputs a cathode mixed gas (13) consisting of air or nitrogen and water vapor, and undergoes an electrochemical deoxidation reaction to generate a synthetic ammonia raw gas (14) consisting of hydrogen and nitrogen; the anode (1) inputs an anode mixed gas (15) consisting of a combustible gas, water vapor and / or carbon dioxide, and undergoes a partial oxidation reaction with oxygen ions generated by the cathode deoxidation reaction and transmitted to the anode (1), to generate a synthetic gas (16) containing hydrogen, carbon monoxide and carbon dioxide.

2. A solid oxide electrolysis cell for co-producing synthetic ammonia feed gas and synthesis gas according to claim 1, characterized in that: The electrolyte (2) is one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, doped cerium oxide, strontium magnesium-doped lanthanum gallate, doped barium zirconate, and doped barium ceria.

3. A solid oxide electrolysis cell for co-producing synthetic ammonia feed gas and synthesis gas according to claim 1, characterized in that: The electronic conductive phase is Ni, Cu, 430L, (La 1-x Sr x )(Cr 1-y Fe y ) 3-δ , (La 1-x Sr x )(Cr 1-y Mn y ) 3-δ ,La 2-x Sr x Fe 2-y-z Ni y Mo z O 6-δ 、430L-(La 1-x Sr x )(Cr 1-y Fe y ) 3-δ One or more of the following, wherein 0<x<1, 0<y<1, 0<δ<1; the oxygen ion conductive phase is one or more of yttria-stabilized zirconia, scandia-stabilized zirconia, doped cerium oxide, strontium magnesium-doped lanthanum gallate, doped barium zirconate, and doped barium ceria.

4. A solid oxide electrolysis cell for co-producing synthetic ammonia feed gas and synthesis gas according to claim 1, characterized in that: The inner wall of the porous composite ceramic is covered with a nano catalyst, and the nano catalyst is Ni, Fe, Co, FeNi3, Ce 1-x Sm x O 2-δ 、Ce 1-x G x O 2-δ , (La 1-x Sr x )(Co 1-y Fe y ) 3-δ 、(Ba 1-x Sr x )(Co 1-y Fe y ) 3-δ 、(Sm 1- x Sr x )CoO 3-δ 、SmBaCo2O 5+δ 、LaBa 0.5 Sr 0.5 Co2O 5+δ 、SmBa 0.5 Sr 0.5 Co2O 5+δ ,BaGd 0.8 La 0.2 Co2O 6-δ ,La 2- x Sr x Fe 2-y-z Ni y Mo z O 6-δ One or more of, wherein 0<x<1, 0<y<1, 0<δ<1.

5. The solid oxide electrolysis cell for co-producing synthetic ammonia feed gas and synthesis gas according to claim 1, characterized in that: The operating temperature range of the solid oxide electrolytic cell is 300-1000° C., and the electrolysis voltage between the cathode (3) and the anode (1) is 0.1-2.0V.

6. A solid oxide electrolysis stack, characterized in that: The invention comprises an anode terminal plate (4), an intermediate plate assembly (5) and a cathode terminal plate (6) connected in sequence, wherein the intermediate plate assembly (5) comprises a plurality of repeating units (51), and a connecting plate (52) is arranged between the repeating units (51); the repeating unit (51) comprises an anode seal (511), an anode current collector (512), an electrolytic cell (513), a middle frame (514), a cathode current collector (515) and a cathode seal (516), wherein the anode seal (511), the middle frame (514) and the cathode seal (516) are all hollow frames, and the anode seal (511) and the electrolytic cell (513), the middle frame (514), the connecting plate (52) or the anode terminal plate (4) form an anode. The invention relates to an anode chamber (7), wherein the anode current collector (512) is arranged in the anode chamber (7), the cathode sealing member (516) and the electrolytic cell (513), the middle frame (514), the connecting plate (52) or the cathode end plate (6) form a cathode chamber (8), the cathode current collector (515) is arranged in the cathode chamber (8), and the anode chamber (7) and the cathode chamber (8) are isolated from each other; the electrolytic cell (513) comprises an anode (1), an electrolyte (2) and a cathode (3); the anode (1) and the cathode (3) are made of a porous composite ceramic comprising an electronic conductive phase and an oxygen ion conductive phase, the volume fraction of the electronic conductive phase is not less than 40%, and the porosity of the porous composite ceramic is 5 to 95%.

7. A solid oxide electrolysis stack according to claim 6, characterized in that: An anode raw material gas inlet (9) is provided on one side of the cathode end plate (6) and the intermediate plate assembly (5), and a cathode raw material gas inlet (10) is provided on the other side; an anode raw material gas outlet (11) is provided on one side of the anode end plate (4) and the intermediate plate assembly (5), and a cathode raw material gas outlet (12) is provided on the other side; the anode raw material gas inlet (9) is connected to the anode raw material gas outlet (11) through the anode chamber (7), and the cathode raw material gas inlet (10) is connected to the cathode raw material gas outlet (12) through the cathode chamber (8).

8. A solid oxide electrolysis stack according to claim 6, characterized in that: The anode current collector (512) and the cathode current collector (515) are made of foam nickel, nickel felt, nickel mesh, foam copper, copper felt, copper mesh, stainless steel mesh, porous (La 1-x Sr x )TiO 3–δ 、Porous La 2-x Sr x Fe 2-y-z Ni y Mo z O 6-δ is made of one or more materials, wherein 0<x<1, 0<y<1, 0<δ<1.

9. The method for preparing ammonia and fuel by a solid oxide electrolysis stack according to claim 6, characterized in that: The invention comprises the following steps: the cathode (3) inputs a cathode mixed gas (13) consisting of air or nitrogen and water vapor, and an electrochemical deoxidation reaction occurs in the cathode chamber (8) to generate a synthetic ammonia raw gas (14) consisting of hydrogen and nitrogen; the anode (1) inputs an anode mixed gas (15) of one or more of combustible gas, water vapor and / or carbon dioxide, and a partial oxidation reaction occurs in the anode chamber (7) with oxygen ions generated by the cathode deoxidation reaction and transmitted to the anode (1) to generate a synthetic gas (16) containing hydrogen, carbon monoxide and carbon dioxide, and then the synthetic gas (16) containing hydrogen, carbon monoxide and carbon dioxide is converted into synthetic fuel.

10. A system for preparing ammonia and fuel, characterized in that: The system comprises a raw material supply control module, a solid oxide electrolysis module, a process gas storage and pressurization module, an ammonia synthesis module, a synthetic fuel module and a control module which are connected in sequence, wherein the raw material supply control module is used to control the composition and flow rate of the cathode mixed gas (13) and the anode mixed gas (15); the solid oxide electrolysis module comprises one or more solid oxide electrolysis stacks, ejectors, heat exchangers, heaters and condensers as described in claim 6, which are used to generate ammonia synthesis raw gas (14) and a synthetic gas (16) containing hydrogen, carbon monoxide and carbon dioxide; the process gas storage and pressurization module is used to pressurize the ammonia raw gas (14) and the synthetic gas (16) containing hydrogen, carbon monoxide and carbon dioxide and output them to the ammonia synthesis module and the synthetic fuel module respectively, and the purge gas of the ammonia synthesis module and the synthetic fuel module is circulated to the solid oxide electrolysis module to improve the raw material utilization rate and the system energy efficiency.

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