Low-carbon high-temperature gas-cooled reactor ammonia synthesis system and method

Abstract

The present invention relates to the field of ammonia synthesis technology, and more specifically to a low-carbon, high-temperature gas-cooled reactor ammonia synthesis system and a low-carbon, high-temperature gas-cooled reactor ammonia synthesis method. The system provided by the present invention utilizes the heat of the high-temperature helium from the high-temperature gas-cooled reactor unit through a steam heat exchange unit and uses the resulting high-pressure, high-temperature steam in the ammonia synthesis unit, thereby providing the ammonia synthesis reaction conditions in the ammonia synthesis unit and improving energy utilization efficiency. Furthermore, the method provided by the present invention simplifies the process flow, particularly by utilizing the high-temperature, low-carbon heat energy from the high-pressure gas-cooled reactor to provide a high-temperature environment for the ammonia synthesis reaction, thereby reducing carbon emissions.

Description

Technical Field

[0001] The present invention relates to the technical field of synthetic ammonia, and in particular to a low-carbon high-temperature gas-cooled reactor synthetic ammonia system and a low-carbon high-temperature gas-cooled reactor synthetic ammonia method. Background Art

[0002] As a key chemical raw material, ammonia plays a vital role in modern industrial production and has the potential to become a green, carbon-free energy source in the future, replacing carbon-containing energy. Approximately 200 million tons of ammonia are synthesized annually. A key precursor for fertilizer production, a convenient hydrogen carrier, and an emerging clean fuel, ammonia is one of the most important industrial chemicals for humanity and the Earth's ecosystem.

[0003] Currently, industrial ammonia synthesis primarily utilizes the Haber-Bosch process, which involves the reaction of nitrogen (N2) with hydrogen (H2) over an iron or ruthenium-based catalyst. The reaction is as follows: N2 + 3H2 → 2NH3, with ΔH = -92.4 kJ / mol. This process is exothermic and can be promoted by high pressure and low temperature. However, the reaction kinetics are slow, so high temperatures are required to accelerate the reaction. However, high temperatures can cause the synthesized NH3 to decompose, so high pressure is introduced to reduce this decomposition. The Haber-Bosch process, based on iron-based catalysts, typically requires temperatures of 300-500°C and pressures of 10-20 MPa. This process is extremely energy-intensive. The raw nitrogen (N2) is primarily produced by air separation using energy-intensive cryogenic or pressure swing adsorption processes. Because its molecules contain a highly stable N≡N structure with a bond energy of up to 941 kJ / mol, high-temperature activation is required for ammonia synthesis. Each ton of ammonia produced is associated with approximately 1.87 tons of CO2 emissions, resulting in significant waste. Furthermore, the hydrogen consumed during the reaction accounts for 3-5% of the world's annual natural gas consumption.

[0004] Nuclear energy is widely recognized worldwide as a safe, clean, and economical alternative to traditional coal and oil-based energy. Traditional pressurized water reactor (PWR) or high-temperature gas-cooled reactor (HTGR) nuclear power plants primarily generate electricity through steam-driven turbines, resulting in relatively low overall thermal efficiency.

[0005] Therefore, there is an urgent need for a synthetic ammonia process based on a high-temperature gas-cooled reactor unit. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems of high energy consumption, large amounts of CO2 emissions, complex processes and harsh conditions in the existing process routes for synthesizing ammonia, and to provide a low-carbon, high-temperature gas-cooled reactor ammonia synthesis system and a low-carbon, high-temperature gas-cooled reactor ammonia synthesis method, thereby expanding the scope of application of high-temperature gas-cooled reactors, realizing efficient utilization of nuclear energy heating, and having the advantages of low consumption and low carbon.

[0007] In order to achieve the above-mentioned object, the first aspect of the present invention provides a low-carbon high-temperature gas-cooled reactor ammonia synthesis system, which comprises: a high-temperature gas-cooled reactor unit I, a steam heat exchange unit II, an ammonia synthesis unit III, and an ammonia condensation unit IV connected in sequence;

[0008] The high temperature gas-cooled reactor unit 1 is used to produce high temperature helium;

[0009] The steam heat exchange unit II is used to perform a first heat exchange on the high-temperature helium and the deoxygenated feed water to obtain low-temperature helium converted from the high-temperature helium and high-pressure high-temperature steam converted from the deoxygenated feed water;

[0010] The ammonia synthesis unit III is used to synthesize ammonia using high-pressure hydrogen and high-pressure nitrogen as reaction gases in the presence of the high-pressure, high-temperature steam to obtain an ammonia-rich mixed gas and condensed water converted from the high-pressure, high-temperature steam;

[0011] The ammonia condensing unit IV is used to condense the ammonia-rich mixed gas to obtain liquid ammonia and unreacted gas;

[0012] The low-temperature helium outlet of the steam heat exchange unit II is connected to the high-temperature gas-cooled reactor unit I for first heating the low-temperature helium.

[0013] Preferably, the condensate outlet of the ammonia synthesis unit III is connected to the deoxygenated feed water inlet of the steam heat exchange unit II, so as to return the condensate and mix it into the deoxygenated feed water.

[0014] Preferably, the system further comprises: a heater VII provided on the pipeline connecting the unreacted gas outlet of the ammonia condensation unit IV and the synthetic ammonia unit III, for performing a second heating on a portion of the unreacted gas to obtain heated unreacted gas.

[0015] Preferably, a heat exchanger VIII connected to the ammonia-rich mixed gas outlet of the synthetic ammonia unit III and the unreacted gas outlet of the ammonia condensation unit IV is used to perform a second heat exchange on the ammonia-rich mixed gas and the remaining part of the unreacted gas to obtain a heat-exchanged ammonia-rich mixed gas converted from the ammonia-rich mixed gas, and a heat-exchanged unreacted gas converted from the remaining part of the unreacted gas.

[0016] A second aspect of the present invention provides a method for synthesizing ammonia in a low-carbon, high-temperature gas-cooled reactor, the method comprising the following steps:

[0017] (1) performing a first heat exchange on high-temperature helium gas from a high-temperature gas-cooled reactor unit and deoxygenated feed water to obtain low-temperature helium gas converted from the high-temperature helium gas and high-pressure, high-temperature steam converted from the deoxygenated feed water;

[0018] (2) in the presence of the high-pressure, high-temperature steam, using high-pressure hydrogen and high-pressure nitrogen as reaction gases to synthesize ammonia, thereby obtaining an ammonia-rich mixed gas and condensed water converted from the high-pressure, high-temperature steam;

[0019] (3) condensing the ammonia-rich mixed gas to obtain liquid ammonia and unreacted gas;

[0020] The low-temperature helium is returned to the high-temperature gas-cooled reactor unit and subjected to a first heating.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) The system provided by the present invention uses the high-temperature helium of the high-temperature gas-cooled reactor unit through a steam heat exchange unit and uses the obtained high-pressure high-temperature steam in the ammonia synthesis unit, thereby using the heat of the high-temperature helium to provide the ammonia synthesis reaction conditions for the ammonia synthesis unit, thereby improving energy utilization efficiency; at the same time, the obtained low-temperature helium is returned to the high-temperature gas-cooled reactor unit, realizing the recycling of helium, which has the advantages of low energy and low carbon;

[0023] (2) The system provided by the present invention realizes the recycling of feed water by connecting the condensate outlet of the ammonia synthesis unit to the deoxygenated feed water inlet of the steam heat exchange unit, especially by returning the deoxygenated condensate and mixing it with the deoxygenated feed water;

[0024] (3) The system provided by the present invention connects the unreacted gas outlet of the ammonia condensation unit to the ammonia synthesis unit, so as to return the unreacted gas and carry out the ammonia synthesis reaction. In particular, a heat exchanger is provided between the ammonia synthesis unit and the ammonia condensation unit to carry out a second heat exchange between the ammonia-rich mixed gas and the remaining unreacted gas, and the unreacted gas after the heat exchange is returned to the ammonia synthesis unit, thereby realizing heat recycling and having high efficiency and low carbon.

[0025] (4) The method provided by the present invention simplifies the process flow, especially by using the high-temperature, low-carbon thermal energy of a high-pressure gas-cooled reactor to provide a high-temperature environment for the synthetic ammonia reaction, thereby reducing carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of a system for synthesizing ammonia using a low-temperature and high-temperature gas-cooled reactor unit provided by the present invention.

[0027] Description of Reference Numerals

[0028] I. High-temperature gas-cooled reactor unit II. Steam heat exchange unit III. Ammonia synthesis unit

[0029] IV, ammonia condensation unit V, first booster VI, deoxidation unit

[0030] VII, heater VIII, heat exchanger IX, second booster

[0031] 1. High temperature helium 2. Deoxygenated water 3. High pressure and high temperature steam

[0032] 4. Low temperature helium 5. High pressure hydrogen 6. High pressure nitrogen

[0033] 7. Ammonia-rich mixed gas 8. Condensate 9. Liquid ammonia

[0034] 10. Unreacted gas 11. Unreacted gas after heating 12. Ammonia-rich mixed gas after heat exchange

[0035] 13. Unreacted gas after heat exchange 14. High-pressure unreacted gas 15. Condensed water after deoxidation DETAILED DESCRIPTION

[0036] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0037] In the present invention, unless otherwise specified, the terms "first" and "second" do not indicate a sequential order or limit the materials or steps involved. They are used solely to distinguish between different materials or steps. For example, the "first" and "second" in "first heat exchange" and "second heat exchange" simply indicate that they are not the same heat exchangers; the "first" and "second" in "first supercharger" and "second supercharger" simply indicate that they are not the same superchargers.

[0038] The first aspect of the present invention provides a low-carbon high-temperature gas-cooled reactor ammonia synthesis system, such as Figure 1 As shown, the system includes: a high temperature gas-cooled reactor unit I, a steam heat exchange unit II, a synthetic ammonia unit III, and an ammonia condensation unit IV connected in sequence;

[0039] The high-temperature gas-cooled reactor unit I is used to produce high-temperature helium 1; the steam heat exchange unit II is used to perform a first heat exchange between the high-temperature helium 1 and the deoxygenated feed water 2 to obtain low-temperature helium 4 converted from the high-temperature helium 1 and high-pressure, high-temperature steam 3 converted from the deoxygenated feed water 2; the ammonia synthesis unit III is used to perform an ammonia synthesis reaction using high-pressure hydrogen 5 and high-pressure nitrogen 6 as reaction gases in the presence of the high-pressure, high-temperature steam 3 to obtain an ammonia-rich mixed gas 7 and condensate 8 converted from the high-temperature steam 3; the ammonia condensation unit IV is used to condense the ammonia-rich mixed gas 7 to obtain liquid ammonia 9 and unreacted gas 10;

[0040] The low-temperature helium outlet of the steam heat exchange unit II is connected to the high-temperature gas-cooled reactor unit I for first heating the low-temperature helium 4.

[0041] In the present invention, unless otherwise specified, the "ammonia-rich mixed gas" refers to a mixed gas containing ammonia, unreacted nitrogen and unreacted hydrogen; and the "unreacted gas" refers to unreacted nitrogen and unreacted hydrogen.

[0042] According to the present invention, preferably, Figure 1 As shown, the system further includes a first booster V connected to the high-temperature gas-cooled reactor unit I and the low-temperature helium outlet of the steam heat exchange unit II, for first boosting the low-temperature helium 4. This arrangement enables the recycling of helium and reduces energy consumption.

[0043] In the present invention, unless otherwise specified, the ammonia synthesis unit includes but is not limited to an ammonia synthesis reactor, and the present invention does not limit the type of the ammonia synthesis reactor.

[0044] According to the present invention, preferably, Figure 1 As shown, the condensate outlet of the ammonia synthesis unit III is connected to the deoxygenated feed water inlet of the steam heat exchange unit II, for returning the condensate 8 and mixing it with the deoxygenated feed water 2. In the present invention, unless otherwise specified, the condensate and deoxygenated feed water enter the steam heat exchanger II for recycling.

[0045] According to the present invention, preferably, Figure 1 As shown, the system further includes: a deoxygenation unit VI connected to the condensate outlet of the synthetic ammonia unit III and the deoxygenated feed water inlet of the steam heat exchange unit II, for deoxygenating the condensate 8 to obtain deoxygenated condensate 15 which is returned and mixed with the deoxygenated feed water 2.

[0046] In the present invention, unless otherwise specified, the ammonia condensing unit includes but is not limited to an ammonia condenser, and the present invention does not limit the type of the ammonia condenser.

[0047] According to the present invention, preferably, Figure 1 As shown, the unreacted gas outlet of the ammonia condensation unit IV is connected to the ammonia synthesis unit III, so as to return the unreacted gas 10 and perform the ammonia synthesis reaction.

[0048] According to the present invention, preferably, Figure 1 As shown, a heater VII is provided on the pipeline connecting the unreacted gas outlet of the ammonia condensation unit IV and the synthetic ammonia unit III, for performing a second heating on a portion of the unreacted gas 10 to obtain heated unreacted gas 11 .

[0049] According to the present invention, preferably, Figure 1 As shown, the system also includes: a heat exchanger VIII connected to the ammonia-rich mixed gas outlet of the synthetic ammonia unit III and the unreacted gas outlet of the ammonia condensation unit IV, for performing a second heat exchange on the ammonia-rich mixed gas 7 and the remaining part of the unreacted gas 10 to obtain a heat-exchanged ammonia-rich mixed gas 12 converted from the ammonia-rich mixed gas 7, and a heat-exchanged unreacted gas 13 converted from the remaining part of the unreacted gas 10.

[0050] According to the present invention, preferably, Figure 1 As shown, the outlet of the heat exchanged ammonia-rich mixed gas of the heat exchanger VIII is connected to the ammonia condensation unit IV, which is used to condense the heat exchanged ammonia-rich mixed gas 12.

[0051] According to the present invention, preferably, Figure 1 As shown, the outlet of the heat exchanged unreacted gas of the heat exchanger VIII is connected to the ammonia synthesis unit III, so as to return the heat exchanged unreacted gas 13 and perform the ammonia synthesis reaction.

[0052] According to the present invention, preferably, Figure 1 As shown, the system further includes: a second booster IX connected to the heated unreacted gas outlet of the heater VII, the heat exchanged unreacted gas outlet of the heat exchanger VIII and the synthetic ammonia unit III, for independently performing a second boosting on the heated unreacted gas 11 and the heat exchanged unreacted gas 13 to obtain a high-pressure unreacted gas 14.

[0053] According to a particularly preferred embodiment of the present invention, a preferred low-carbon high-temperature gas-cooled reactor ammonia synthesis system comprises: a high-temperature gas-cooled reactor unit I, a steam heat exchange unit II, an ammonia synthesis unit III, a heat exchanger VIII and an ammonia condensation unit IV, as well as a deoxidation unit VI and a heater VII connected in sequence;

[0054] The high-temperature gas-cooled reactor unit I is used to produce high-temperature helium; the steam heat exchange unit II is used to perform a first heat exchange on the high-temperature helium and deoxygenated feed water to obtain low-temperature helium converted from the high-temperature helium and high-pressure, high-temperature steam converted from the deoxygenated feed water; the synthetic ammonia unit III is used to use high-pressure hydrogen and high-pressure nitrogen as reaction gases to perform a synthetic ammonia reaction in the presence of the high-pressure, high-temperature steam to obtain an ammonia-rich mixed gas and condensate converted from the high-pressure, high-temperature steam; the heater VII is connected to the unreacted gas of the ammonia condensing unit IV. outlet and the synthetic ammonia unit III, for performing a second heating on a portion of the unreacted gas to obtain heated unreacted gas; the heat exchanger VIII is also connected to the unreacted gas outlet of the ammonia condensing unit IV, for performing a second heat exchange on the ammonia-rich mixed gas and the remaining portion of the unreacted gas to obtain a heat-exchanged ammonia-rich mixed gas converted from the ammonia-rich mixed gas, and a heat-exchanged unreacted gas converted from the remaining portion of the unreacted gas; the ammonia condensing unit IV is used to condense the heat-exchanged ammonia-rich mixed gas to obtain liquid ammonia and the unreacted gas;

[0055] The low-temperature helium outlet of the steam heat exchange unit II is connected to the high-temperature gas-cooled reactor unit I for first heating the low-temperature helium;

[0056] The deoxygenation unit V is provided between the condensate outlet of the ammonia synthesis unit III and the deoxygenated feed water inlet of the steam heat exchange unit II, and is used to deoxygenate the condensate. The deoxygenated condensate is returned and mixed with the deoxygenated feed water.

[0057] The outlet of the unreacted gas after heat exchange of the heat exchanger VIII is also connected to the ammonia synthesis unit III, so as to return the reaction gas after heat exchange and perform the ammonia synthesis reaction.

[0058] A second aspect of the present invention provides a method for synthesizing ammonia in a low-carbon, high-temperature gas-cooled reactor, the method comprising the following steps:

[0059] (1) performing a first heat exchange on high-temperature helium gas from a high-temperature gas-cooled reactor unit and deoxygenated feed water to obtain low-temperature helium gas converted from the high-temperature helium gas and high-pressure, high-temperature steam converted from the deoxygenated feed water;

[0060] (2) in the presence of the high-pressure, high-temperature steam, using high-pressure hydrogen and high-pressure nitrogen as reaction gases to synthesize ammonia, thereby obtaining an ammonia-rich mixed gas and condensed water converted from the high-pressure, high-temperature steam;

[0061] (3) condensing the ammonia-rich mixed gas to obtain liquid ammonia and unreacted gas;

[0062] The low-temperature helium is returned to the high-temperature gas-cooled reactor unit and subjected to a first heating.

[0063] In the present invention, the first heat exchange utilizes the heat of the high-temperature helium to heat the deoxygenated feed water, thereby converting the deoxygenated feed water into high-temperature and high-pressure steam, which serves as a heat source for the ammonia synthesis reaction.

[0064] In some embodiments of the present invention, preferably, in step (1), the ratio of the high-temperature helium gas (in L) to the deoxygenated feed water (in t) is 0.5-1.5:1, for example, 0.5:1, 0.6:1, 0.8:1, 1:1, 1.1:1, 1.5:1, and any value in a range consisting of any two of these values, preferably 0.6-1.1:1. Wherein, t refers to tons.

[0065] In some embodiments of the present invention, preferably, in step (1), the temperature of the high-temperature helium is 700-1100°C and the pressure is 6.5-7.5 MPa; the temperature of the low-temperature helium is 230-280°C and the pressure is 4-7.5 MPa; the oxygen content in the deoxygenated feed water is ≤14 ppm; the temperature of the high-pressure and high-temperature steam is 520-580°C and the pressure is 9-15 MPa.

[0066] In the present invention, unless otherwise specified, the pressure parameters all refer to gauge pressure; the first heating is intended to heat the low-temperature helium in the core of the high-temperature gas-cooled reactor unit to obtain the high-temperature helium.

[0067] In the present invention, the low-temperature helium discharged from the steam heater is pressurized to 6.5-7.5 MPa by the first pressurization and then enters the high-temperature gas-cooled reactor to extract heat and produce high-temperature helium. Preferably, the low-temperature helium is first pressurized before the first heating.

[0068] In some embodiments of the present invention, preferably, in step (2), the conditions for the ammonia synthesis reaction include: a temperature of 300-500°C and a pressure of 10-20 MPa. In the present invention, the conditions for the ammonia synthesis reaction are all provided by high-pressure, high-temperature steam, that is, by the heat generated by the high-temperature gas-cooled reactor unit, thereby improving heat utilization.

[0069] In some embodiments of the present invention, preferably, the pressures of the high-pressure hydrogen and high-pressure nitrogen in the reaction gas are independently 10-20 MPa.

[0070] In some embodiments of the present invention, preferably, the ammonia content in the ammonia-rich mixed gas is 0-100 volume%, for example, 0 volume%, 20 volume%, 50 volume%, 75 volume%, 95 volume%, 100 volume%, and any value in the range consisting of any two values, preferably 50-95 volume%.

[0071] In some embodiments of the present invention, preferably, the method further comprises: returning the condensate and mixing it into the deoxygenated feed water; further preferably, deoxygenating the condensate, and returning the deoxygenated condensate and mixing it into the deoxygenated feed water.

[0072] In the present invention, there is a wide range of options for the deoxygenation method, as long as the oxygen content in the condensate meets the above-mentioned limited parameters.

[0073] In some embodiments of the present invention, preferably, the method further comprises: returning the unreacted gas and performing the ammonia synthesis reaction; further preferably, subjecting part of the unreacted gas to a second heating, and then subjecting the obtained heated unreacted gas to the ammonia synthesis reaction.

[0074] In some embodiments of the present invention, preferably, the method further comprises: before the condensation, subjecting the ammonia-rich mixed gas and the remaining portion of the unreacted gas to a second heat exchange to obtain a heat-exchanged ammonia-rich mixed gas converted from the ammonia-rich mixed gas, and a heat-exchanged unreacted gas converted from the remaining portion of the unreacted gas.

[0075] In some embodiments of the present invention, the volume ratio of the portion of unreacted gas to the remaining portion of the unreacted gas is preferably 0-100:0-100. This configuration allows the heat of the high-temperature, ammonia-rich mixed gas exiting the reactor to be absorbed by the unreacted gas after cooling in the synthetic ammonia cooler, thereby increasing the temperature of the unreacted gas and reducing the amount of high-pressure steam circulating for heating, thus constituting a waste heat utilization device.

[0076] In some embodiments of the present invention, preferably, the method further comprises: returning the unreacted gas after heat exchange and performing the ammonia synthesis reaction.

[0077] In some embodiments of the present invention, preferably, the method further comprises: independently performing a second pressurization on the heated unreacted gas and the heat-exchanged unreacted gas.

[0078] According to a particularly preferred embodiment of the present invention, a method for synthesizing ammonia in a low-carbon high-temperature gas-cooled reactor comprises the following steps:

[0079] (1) performing a first heat exchange on high-temperature helium gas from a high-temperature gas-cooled reactor unit and deoxygenated feed water to obtain low-temperature helium gas converted from the high-temperature helium gas and high-pressure, high-temperature steam converted from the deoxygenated feed water;

[0080] (2) in the presence of the high-pressure, high-temperature steam, using high-pressure hydrogen and high-pressure nitrogen as reaction gases to synthesize ammonia, thereby obtaining an ammonia-rich mixed gas and condensed water converted from the high-pressure, high-temperature steam;

[0081] (3) subjecting a portion of the unreacted gas to a second heating, and then subjecting the obtained heated unreacted gas to the ammonia synthesis reaction; subjecting the ammonia-rich mixed gas and the remaining portion of the unreacted gas to a second heat exchange, to obtain a heat-exchanged ammonia-rich mixed gas converted from the ammonia-rich mixed gas, and a heat-exchanged unreacted gas converted from the remaining portion of the unreacted gas, and returning the heat-exchanged unreacted gas to the ammonia synthesis reaction;

[0082] (4) condensing the ammonia-rich mixed gas after heat exchange to obtain liquid ammonia and the unreacted gas;

[0083] wherein the low-temperature helium gas is returned to the high-temperature gas-cooled reactor unit and subjected to a first heating;

[0084] wherein the condensate is deoxygenated, and the deoxygenated condensate obtained is returned and mixed with the deoxygenated feed water;

[0085] Wherein, the volume ratio of the part of the unreacted gas to the remaining part of the unreacted gas is 0-100:0-100.

[0086] The present invention will be described in detail below through examples.

[0087] Example 1

[0088] Low carbon high temperature gas cooled reactor ammonia synthesis system, such as Figure 1 As shown, the system includes: a high-temperature gas-cooled reactor unit I, a steam heat exchange unit II, a synthetic ammonia unit III, a heat exchanger VIII and an ammonia condensing unit IV, as well as a first booster V, a deaerator unit VI, a heater VII and a second booster IX connected in sequence;

[0089] The unreacted gas outlet of the ammonia condensation unit IV is connected to the heat exchanger VIII;

[0090] Among them, the first booster V is connected to the low-temperature helium outlet of the steam heat exchange unit II and the high-temperature gas-cooled reactor unit I; the deoxygenation unit VI is connected to the condensate outlet of the synthetic ammonia unit III and the deoxygenation feed water inlet of the steam heat exchange unit II; the heater VII is connected to the unreacted gas outlet of the ammonia condensation unit IV and the synthetic ammonia unit III; the heat exchanger VIII is connected to the unreacted gas outlet of the ammonia condensation unit IV and the synthetic ammonia unit III; the second booster IX is connected to the heat exchanged unreacted gas outlet of the heat exchanger VIII, the heated unreacted gas outlet of the heater VII and the synthetic ammonia unit III.

[0091] A method for synthesizing ammonia in a low-carbon high-temperature gas-cooled reactor, comprising:

[0092] (1) High-temperature helium (temperature 700-1100°C, pressure 6.5-7.5 MPa) from a high-temperature cold gas reactor is subjected to a first heat exchange with deoxygenated feed water (oxygen content <14 ppm) to obtain low-temperature helium (pressure 4-7.5 MPa, temperature 230-280°C) converted from the high-temperature helium and high-pressure, high-temperature steam (temperature 520-580°C, pressure 9-15 MPa) converted from the deoxygenated feed water;

[0093] wherein the ratio of the high temperature helium in L to the deoxygenated feed water in t is 0.6-1.1:1;

[0094] Among them, the low-temperature helium is pressurized to 6.5-7.5MPa and returned to the high-temperature gas-cooled reactor unit for the first heating;

[0095] (2) In the presence of the high-pressure, high-temperature steam, high-pressure hydrogen (pressure of 10-20 MPa) and high-pressure nitrogen (pressure of 10-20 MPa) are used as reaction gases to carry out an ammonia synthesis reaction (temperature of 300-500°C, pressure of 10-20 MPa) to obtain an ammonia-rich mixed gas and condensed water converted from the high-pressure, high-temperature steam;

[0096] The ammonia content in the ammonia-rich mixed gas is 50-95% by volume;

[0097] wherein the condensate is deoxygenated, and the deoxygenated condensate is returned and mixed with the deoxygenated feed water;

[0098] (3) subjecting a portion of the unreacted gas to a second heating step to obtain a heated unreacted gas;

[0099] performing a second heat exchange on the ammonia-rich mixed gas and the remaining unreacted gas to obtain a heat-exchanged ammonia-rich mixed gas converted from the ammonia-rich mixed gas and a heat-exchanged unreacted gas converted from the unreacted gas;

[0100] The volume ratio of the unreacted gas to the remaining unreacted gas is 0-100:0-100;

[0101] The unreacted gas after heating and the unreacted gas after heat exchange are pressurized to 10-20 MPa and returned to the ammonia synthesis unit;

[0102] (4) Condensing the ammonia-rich mixed gas after the heat exchange to obtain liquid ammonia and the unreacted gas.

[0103] The system provided in Example 1 of the present invention uses the heat of the high-temperature helium from the high-temperature gas-cooled reactor unit through a steam heat exchange unit and uses the obtained high-pressure, high-temperature steam in the ammonia synthesis unit, thereby providing ammonia synthesis reaction conditions for the ammonia synthesis unit using the heat of the high-temperature helium, thereby improving energy utilization efficiency. At the same time, the method provided by the present invention simplifies the process flow, especially using the high-temperature, low-carbon thermal energy of the high-pressure gas-cooled reactor to provide a high-temperature environment for the ammonia synthesis reaction, thereby reducing carbon emissions.

[0104] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for synthesizing ammonia using a low-carbon, high-temperature gas-cooled reactor, characterized in that: The method comprises the following steps: (1) performing a first heat exchange on high-temperature helium gas from a high-temperature gas-cooled reactor unit and deoxygenated feed water to obtain low-temperature helium gas converted from the high-temperature helium gas and high-pressure high-temperature steam converted from the deoxygenated feed water; (2) in the presence of the high-pressure, high-temperature steam, using high-pressure hydrogen and high-pressure nitrogen as reaction gases to react to produce ammonia, thereby obtaining an ammonia-rich mixed gas and condensate converted from the high-pressure, high-temperature steam; returning the condensate and mixing it into the deoxygenated feed water; (3) condensing the ammonia-rich mixed gas to obtain liquid ammonia and unreacted gas; wherein the low-temperature helium gas is returned to the high-temperature gas-cooled reactor unit and subjected to a first heating; The high-temperature helium has a temperature of 700-1100°C and a pressure of 6.5-7.5 MPa; the low-temperature helium has a temperature of 230-280°C and a pressure of 4-7.5 MPa; the oxygen content in the deoxygenated feed water is ≤14 ppm; the high-pressure and high-temperature steam has a temperature of 520-580°C and a pressure of 9-15 MPa; The conditions for the ammonia synthesis reaction include: a temperature of 300-500°C and a pressure of 10-20 MPa; the pressures of the high-pressure hydrogen and high-pressure nitrogen in the reaction gas are each independently 10-20 MPa; Part of the unreacted gas is subjected to a second heating, and the heated unreacted gas obtained is then subjected to the ammonia synthesis reaction; before the condensation, the ammonia-rich mixed gas and the remaining part of the unreacted gas are subjected to a second heat exchange to obtain a heat-exchanged ammonia-rich mixed gas converted from the ammonia-rich mixed gas, and the heat-exchanged unreacted gas converted from the remaining part of the unreacted gas is returned and subjected to the ammonia synthesis reaction.

2. The method according to claim 1, wherein In step (1), the ratio of the high-temperature helium in L to the deoxygenated feed water in t is 0.5-1.5:1; And / or, before performing the first heating, the low-temperature helium gas is first pressurized.

3. The method according to claim 2, wherein: In step (1), the ratio of the high-temperature helium measured in L to the deoxygenated feed water measured in t is 0.6-1.1:

1.

4. The method according to claim 1, wherein The method further comprises: deoxygenating the condensate, and returning the deoxygenated condensate to be mixed with the deoxygenated feed water.

5. The method according to claim 1, wherein In step (2), the ammonia content in the ammonia-rich mixed gas is 50-95% by volume.

6. The method according to claim 1, wherein The volume ratio of the part of the unreacted gas to the remaining part of the unreacted gas is 0-100:0-100; And / or, the method further includes: independently performing a second pressurization on the heated unreacted gas and the heat-exchanged unreacted gas.

7. A low-carbon high-temperature gas-cooled reactor ammonia synthesis system, characterized in that: The method according to any one of claims 1 to 6 is performed in a system comprising: A high temperature gas-cooled reactor unit (I), a steam heat exchange unit (II), a synthetic ammonia unit (III), and an ammonia condensation unit (IV) connected in sequence; The high temperature gas-cooled reactor unit (I) is used to produce high temperature helium; The steam heat exchange unit (II) is used to perform a first heat exchange on the high-temperature helium and the deoxygenated feed water to obtain low-temperature helium converted from the high-temperature helium and high-pressure high-temperature steam converted from the deoxygenated feed water; The ammonia synthesis unit (III) is used to synthesize ammonia using high-pressure hydrogen and high-pressure nitrogen as reaction gases in the presence of the high-pressure, high-temperature steam to obtain an ammonia-rich mixed gas and condensed water converted from the high-pressure, high-temperature steam; The ammonia condensation unit (IV) is used to condense the ammonia-rich mixed gas to obtain liquid ammonia and unreacted gas; The low-temperature helium outlet of the steam heat exchange unit (II) is connected to the high-temperature gas-cooled reactor unit (I) for first heating the low-temperature helium; The condensate outlet of the ammonia synthesis unit (III) is connected to the deoxygenated water inlet of the steam heat exchange unit (II); the unreacted gas outlet of the ammonia condensation unit (IV) is connected to the ammonia synthesis unit (III); a heater (VII) is provided on the pipeline connecting the unreacted gas outlet of the ammonia condensation unit (IV) and the ammonia synthesis unit (III); a heat exchanger (VIII) is provided on the pipeline connecting the ammonia-rich mixed gas outlet of the ammonia synthesis unit (III) and the unreacted gas outlet of the ammonia condensation unit (IV), the ammonia-rich mixed gas outlet after heat exchange of the heat exchanger (VIII) is connected to the ammonia condensation unit (IV), and the unreacted gas outlet after heat exchange of the heat exchanger (VIII) is connected to the ammonia synthesis unit (III).

8. The system according to claim 7, wherein: The system further comprises: a first booster (V) connected to the high temperature gas-cooled reactor unit (I) and the low temperature helium outlet of the steam heat exchange unit (II), for performing a first boosting of the low temperature helium.

9. The system according to claim 7, wherein: The system further comprises a deoxygenation unit (VI) connected to the condensate outlet of the ammonia synthesis unit (III) and the deoxygenated feed water inlet of the steam heat exchange unit (II), for deoxygenating the condensate, and the deoxygenated condensate is returned and mixed with the deoxygenated feed water.

10. The system according to claim 7, wherein: The heater (VII) is used to perform a second heating on a portion of the unreacted gas to obtain heated unreacted gas; The heat exchanger (VIII) is used to perform a second heat exchange on the ammonia-rich mixed gas and the remaining part of the unreacted gas to obtain a heat-exchanged ammonia-rich mixed gas converted from the ammonia-rich mixed gas, and a heat-exchanged unreacted gas converted from the remaining part of the unreacted gas; wherein the heat-exchanged ammonia-rich mixed gas is condensed; and the heat-exchanged unreacted gas is returned to the ammonia synthesis reaction.

11. The system according to claim 7, wherein: The system further comprises: a second booster (IX) connected to the outlet of the heated unreacted gas of the heater (VII), the outlet of the heat exchanged unreacted gas of the heat exchanger (VIII), and the ammonia synthesis unit (III), for independently performing a second boosting on the heated unreacted gas and the heat exchanged unreacted gas to obtain high-pressure unreacted gas.

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