Blue ammonia production method

Abstract

The present invention provides a method and system for producing blue ammonia that offers a high percentage of carbon recovery. The method and system of the present invention can be used in any ammonia plant.

Description

Technical Field

[0001] The present invention provides a method and system for generating blue ammonia that provides a higher percentage of carbon recovery. The method and system of the present invention can be used in any ammonia plant.

Background Art

[0002] Blue ammonia is a fossil fuel-based product that is produced while minimizing CO2 emissions to the atmosphere. It is considered a transitional product between conventional fossil fuel-based ammonia and green ammonia produced from green or renewable electricity, water, and air. The CO2 resulting from blue ammonia production must be permanently stored or converted to other chemicals. The main steps for generating blue ammonia are essentially the same as those for generating conventional fossil fuel-based ammonia, the difference being that more carbon derived from carbonaceous fuels is recovered, which offers further processing potential.

[0003] What is important here is that blue ammonia does not emit carbon dioxide when used as a fertilizer or burned. Current available technologies trap almost all of the CO2 generated during the conversion process, making this fuel the first choice for a carbon-free fuel for large-scale use. Blue ammonia is considered an environmentally friendly product that can be used until sufficient renewable or green electricity becomes available to produce green ammonia.

[0004] If the power generation methods can be diversified and continue to create more and more renewable or green energy, the method of green energy that produces hydrogen and ammonia as by-products can be completed, resulting in a completely clean and safe power generation cycle.

[0005] Document WO2018 / 149641 (Patent Document 1) discloses a method for synthesizing ammonia from natural gas, comprising converting a desulfurized natural gas and steam packing with oxygen-enriched air or oxygen into synthesis gas (11), and treating the synthesis gas (11) with a shift reaction and decarbonization, wherein a portion of the CO2-depleted synthesis gas obtained after decarbonization is separated and used as a fuel fraction for one or more furnaces in the conversion section, and the remaining portion of the gas is used to produce ammonia. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] WO2018 / 149641 [Overview of the project]

[0007] The present invention differs from the configuration disclosed in the cited literature in that it recovers at least one hydrogen-rich tail gas from at least one H2PSA and at least one CO2-depleted stream from a CO2 removal step for fuel, carbon recycling and optionally for additional hydrogen production after further purification and separation, enabling the use of more carbon-depleted fuel and thereby achieving a higher carbon recovery rate (up to over 99% compared to the cited literature).

[0008] Summary of the Invention The present invention relates to a method, system, and plant for producing ammonia with a higher percentage of carbon recovery, preferably more than 99%, compared to standard methods, which optimally achieve carbon recovery between approximately 90 and 93%.

[0009] The method of the present invention offers the following advantages: - Applicable to general plants and for improvements; - To achieve complete CO2 recovery, a CO2 removal step is utilized in the ammonia process; - Enables carbon capture of over 99%; - Reduce the amount of Ar entering the ammonia synthesis loop, and therefore reduce the required circulation flow rate in that loop and the water washing required in the cooling off-gas; - The nitrogen content in the recycling stream is reduced compared to conventional technology, thus reducing the required ATR recycling flow rate (F); - At least under cryogenic conditions, a compressor is not necessarily required to compress CO2, as CO2 is pressurized by other means, preferably by pumping, thus reducing operating costs. Using a pump increases the pressure of the rich CO2 product in a less expensive way than using a compressor. This also means less energy consumption.

[0010] The aforementioned advantages are provided by a set of features, including: - The CO2 removal step is performed downstream of the hydrogen purification step, but preferably not exclusively in a cryogenic CO2 removal unit or CO2PSA; - Reduce the combustion of natural gas used in the pilot burner; - Carbon-depleting gases used as fuel in fuel systems, mainly H2 and N2; - Off-gas containing more than 40% by volume of methane and / or CO is reintroduced to the reforming or desulfurization section as additional feed gas.

[0011] The present invention discloses a method and plant similar to that described in WO2022 / 284434, but instead provides a hydrogen purification unit, such as a PSA or NWU or others, upstream of a carbon removal unit (e.g., a cryogenic carbon recovery unit or a CO2 PSA unit or others for the same purpose). This new layout can reduce the total cost of ownership for ammonia production compared to standard solutions, with total cost of ownership including approximately 10 years of CAPEX and OPEX.

[0012] High-purity hydrogen is recovered in the hydrogen PSA unit, and optionally, intermediate hydrogen-rich fuel gas (tail gas) is sent to the fuel system either directly or pre-combined with other streams.

[0013] The CO2-rich PSA tail gas stream is sent to a CO2 removal unit (preferably a cryogenic CO2 removal unit) from which high-purity CO2 products are recovered. Due to cryogenic conditions, the CO2 products or CO2-rich stream can be pressurized to the required high CO2 pressure without being compressed by one or more compressor units, which is a standard solution, and can be pumped, for example.

[0014] On the other hand, the CO2 depletion stream(s) can be optionally recycled by pressurizing and returning to steps a) and / or b) after further purification in one or more PSA and / or membrane units, or supplied to the fuel system directly or after premixing with other streams. The CO2 depletion stream from the CO2 removal unit includes the main portion of unconverted hydrocarbons from the reforming step and the main portion of unconverted CO from the shift step. A portion of this stream can be recycled directly and used as reforming feed material, or the hydrogen portion may be separated beforehand. The remaining portion of the stream or the separated hydrogen can be used as fuel. [Brief explanation of the drawing]

[0015] Figure 1 shows the Topsoe SynCOR ammonia. 商標 This outlines a prior art method for producing ammonia according to one embodiment of WO2022 / 248434, using the following process: a) Desulfurization b0) Preliminary modification b) Modification (ATR) c) Shift section d) CO2 removal e) Nitrogen washing or PSA f) Ammonia synthesis h) Off-gas recycle compressor g) Fuel system(s) Stream (4,8) Recycle off-gas stream Stream (5,7) Hydrogen-rich fuel containing nitrogen (replacing the use of natural gas as fuel) Stream 2 Flash gas from CO2 removal Here, the CO2 removal unit is upstream of the hydrogen purification unit.

[0016] Figure 2 shows an overview of a prior art method for producing ammonia according to another embodiment in WO2022 / 248434, which uses a steam reformer followed by an autothermal reformer in syngas production: a) Desulfurization b0) Pre-reforming b) Reforming (SMR) b) Reforming (ATR) c) Shift section d) CO2 removal e) Nitrogen washing or PSA or methanator f) Ammonia synthesis h) Off-gas recycle compressor g) Fuel system(s) Stream (4,8) Recycle off-gas stream Stream (5,7) Hydrogen-rich fuel containing nitrogen (replacing the use of natural gas as fuel) Stream (2) Flash gas from CO2 removal Here too, the CO2 removal unit is upstream of the hydrogen purification unit.

[0017] Figure 3 outlines a method for producing ammonia according to a preferred embodiment of the present invention, showing a hydrogen purification unit (e.g., a PSA or nitrogen washing unit or others) upstream of a CO2 removal unit (e.g., a cryogenic CO2 removal unit or a CO2 PSA unit), the remaining tail gas from the hydrogen purification unit entering the CO2 removal unit. a) Desulfurization b0) Preliminary modification b) Modification c) Shift section d) Hydrogen purification unit e) CO2 removal f) Ammonia synthesis g) Fuel system(s) (multiple systems possible) h) Off-gas recycling compressor

[0018] Figure 4 outlines a method for producing ammonia according to a preferred embodiment of the present invention, showing a first hydrogen purification unit (e.g., a PSA or nitrogen washing unit or other) upstream of a CO2 removal unit (e.g., a cryogenic CO2 removal unit or a CO2 PSA unit), where H2 product C is produced, and the hydrogen-rich fuel stream D (having a different or identical composition to C) and the remaining tail gas from the hydrogen purification unit enter the CO2 removal unit to produce a CO2-rich stream (E) and a CO2-depleted stream (K). Preferably, the argon content in the feed material (B) is low, and the split stream of hydrogen products is used as fuel, i.e., streams C and D have the same composition. In the previous layout, e.g., Figure 3, the argon content is higher, and the hydrogen-rich tail gas stream(s) have a different composition from C. In Figure 4, the CO2 depletion stream is led to a second hydrogen purification unit, preferably a PSA (PSA-1), which generates a CO2-rich stream (J) and a further CO2 depletion stream (H). The CO2-rich stream (J) is recycled back into the tail gas from the first hydrogen purification unit, and the further CO2 depletion stream (H) is split between a first stream entering a third hydrogen purification unit, preferably a PSA (PSA-2) or membrane, and a separate stream (G) used as fuel gas. The third purification unit, which is a PSA, generates hydrogen product (L) and stream F, which is preferably mixed with hydrogen product (C) and has many different uses (e.g., in processes for the production of chemicals such as ammonia or methanol, in fuel production, storage, or others), and stream F is recycled to the ATR.

[0019] Streams D and G are used as fuel. Stream D has a higher hydrogen content than Stream G. Streams D and G are adjusted according to the required carbon recovery rate.

[0020] Alternatively, if the third hydrogen purification unit is a membrane, stream L is the hydrogen-rich fuel stream. In this alternative, streams D, G, and L are used for fuel.

[0021] definition Blue ammonia is ammonia produced using fossil fuels, in which at least 90% of the carbon in the fossil fuels is recovered and used in other products and processes, or stored.

[0022] Catalyst poisons refer to substances that reduce the effectiveness of a catalyst in a chemical reaction. Theoretically, since catalysts are not consumed in a chemical reaction, they can be reused indefinitely. However, in practice, poisons originating from the reactants or products of the reaction itself accumulate on the surface of solid catalysts, reducing their effectiveness. For this reason, when the effectiveness of a catalyst reaches a certain low level, steps are taken to remove the poison or replenish the active catalyst components that may have reacted with the poison. Common poisons encountered include carbon on silica-alumina catalysts in petroleum cracking; sulfur, arsenic, or lead on metal catalysts in hydrogenation or dehydrogenation reactions; and oxygen and water on iron catalysts used in ammonia synthesis.

[0023] Carbon capture, or carbon capture and storage (CCS), is a process that involves trapping carbon dioxide (CO2) at its emission source to prevent its release into the atmosphere, and then storing it in a way that prevents it from escaping. This is considered a crucial strategy in efforts to combat global climate change. Once captured, the CO2 is then transported and stored underground, typically in depleted oil and gas fields or deep saltwater aquifers.

[0024] Carbon capture and utilization (CCU) is preferred, which involves capturing CO2 and then converting it into useful products, such as chemicals (e.g., methanol), fuels, or building materials.

[0025] A contaminant means an undesirable substance or element. In the context of this invention, a contaminant includes a catalyst poison.

[0026] Flue gas refers to the exhaust gas released as a byproduct of the combustion process, typically from a reformer unit or combustion heater unit (where the initial production of hydrogen-rich synthesis gas occurs). Flue gas can also be a valuable heat source for other parts of the process, and the CO2 contained therein can potentially be recovered, utilized, or stored to reduce greenhouse gas emissions.

[0027] Green ammonia is ammonia produced using green electricity, water, and air.

[0028] Green electricity is electricity generated from renewable resources such as wind, solar, hydro, or geothermal energy.

[0029] In the context of this invention, an ammonia synthesis catalyst means any catalyst suitable for synthesizing ammonia. These catalysts are preferably iron (Fe)-based, but may also include other catalysts suitable for the same purpose and operating under similar conditions.

[0030] The fuel system includes a fuel system for supplying fuel to the combustion side of a tubular reformer and / or combustion heater and / or auxiliary boiler and / or gas turbine. These systems are equipped with one or more burners, where the incoming fuel stream is burned together with air at variable temperature and pressure.

[0031] Makeup ammonia, or traded ammonia, contains ammonia (NH3) and water (H2O), preferably with a water content of 0.2–0.5% by weight. It is usually supplied as a liquid, but may also be a solution containing different physical states. The effect of water in the ammonia feedstock in the ammonia decomposition process is mainly due to process poisoning, which usually must be carried out at high temperatures. This increases the process cost for ammonia decomposition, as well as the cost of construction materials in the plant. According to the National Bureau of Standards, ammonia must conform to the following properties: a minimum purity of 99.98% (by weight), a maximum of 0.0005% (by weight) of oil, and a maximum of 0.02% (by weight) of water.

[0032] A PSA unit refers to a pressure swing adsorption unit. Typically, a mixture of gases, including hydrogen, is supplied to the PSA unit under high pressure. The unit contains a substance known as an adsorbent (which preferentially adsorbs certain gas molecules (e.g., CO, CO2, N2, CH4) over other substances (in this case, hydrogen)). As a result, hydrogen gas passes through the unit while other gases are adsorbed onto the substance. When the adsorbent material becomes saturated with the adsorbent gas, the pressure in the unit is reduced, thereby desorbing and removing the adsorbent gas from the unit. This gas is then purged with some of the generated hydrogen to remove any remaining adsorbent gas, regenerate the adsorbent material, and the unit is repressurized.

[0033] In the context of hydrogen production or purification, an overhead purification unit, such as a PSA, refers to a purification unit located at a higher point or "overhead" in the process flow diagram (e.g., a pressure swing adsorption (PSA) unit). The PSA can be, for example, hydrogen PSA or CO2 PSA. The purification unit may be, for example, a membrane. Different purification units are optimal in different parts of the preferred layout (Figure 4).

[0034] The term "shift reaction" refers to the water-gas shift reaction (WGSR) or simply the shift reaction, which is the reaction of carbon monoxide and water vapor to form carbon dioxide and hydrogen.

[0035] [ka] WGSR is an important industrial reaction used in the production of ammonia, hydrocarbons, methanol, and hydrogen. It is also often used in conjunction with the steam reforming of methane and other hydrocarbons. In the Fischer-Tropsch process, WGSR is one of the most important reactions used to maintain the balance of the H2 / CO ratio. The water-gas shift reaction is a moderately exothermic and reversible reaction. Thus, as the temperature increases, the reaction rate increases, but the production of carbon dioxide becomes less desirable. Due to its exothermic nature, a high percentage of carbon monoxide is thermodynamically desirable at low temperatures. Despite the thermodynamic advantage at low temperatures, the reaction is faster at high temperatures.

[0036] A shift unit or section refers to a process step in which a shift reaction occurs.

[0037] Tail gas from a purification unit, such as a pressure swing adsorption (PSA) unit, refers to the gas discharged from the system during the depressurization and regeneration phases of the PSA cycle, and typically contains impurities that were initially present in the feed material gas and adsorbed onto the adsorbent material during the adsorption phase. These may include gases such as carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nitrogen (N2), and residual unadsorbed hydrogen. During the depressurization and regeneration phases, these adsorbed gases are desorbed from the adsorbent material and discharged from the system, forming the tail gas. The composition of the tail gas may vary depending on the specific feed material gas composition and the type of adsorbent material used in the PSA unit. Optionally, the tail gas can be recovered or treated, for example, by recycling it back into the process, using it as fuel, or by treating it to remove specific components before discharge.

[0038] Description of the Invention Reducing CO2 emissions is a challenge that needs to be addressed in the chemical industry. The production of ammonia using hydrocarbons as a feedstock inevitably results in CO2 formation, which typically results in at least two CO2-containing process streams: one nearly pure CO2 stream extracted from the synthesis gas scrubbing section and one or more flue gas streams. The CO2 streams can be used for further chemical processing or stored. CO2 in the flue gas streams needs to be recovered until a similar use can be found. Flue gas recovery processes incur high operating and capital costs. Therefore, limiting the CO2 content in flue gas is advantageous.

[0039] It is well known that using carbon-free fuels can avoid CO2 in flue gases. Generally, hydrocarbons, such as natural gas, and carbon-containing off-gases derived from processes are used as fuels.

[0040] The advantages of WO2022 / 248434 are that the main portion of these fuels is replaced by an internal hydrogen-rich stream, and unavoidable off-gases are recycled into the process. By applying this invention, the CO2 content in the flue gas stream can be reduced by more than 90%. If a pure CO2 stream (1) is utilized or stored, the product ammonia is considered blue.

[0041] Traditional ammonia production involves the utilization of off-gases from ammonia recovery and synthesis gas preparation steps to supplement natural gas as the primary fuel for combustion heaters / process furnaces. This results in carbon emissions from the flue gas stack, which can be partially recovered by using carbon recovery technology-based solutions. Recovery rates for such plants (including carbon recovery from flue gas) do not exceed 90%, and it is a capital-intensive process.

[0042] In the proposed layout, a high-purity hydrogen product stream and a hydrogen-rich gas stream are recovered in a hydrogen purification unit (e.g., PSA, etc.), and the remaining CO2-rich tail gas from the hydrogen purification unit is sent to a CO2 removal unit, preferably a cryogenic CO2 removal unit, from which the high-purity CO2 product (CO2-rich stream) is recovered and pressurized. Ammonia synthesis gas is produced by adding nitrogen to the high-purity hydrogen product stream. In a preferred embodiment, using a cryogenic CO2 removal unit, the liquid CO2 product is pumped to the high CO2 pressure required for cryogenic conditions instead of being pressurized, preferably compressed (this is a standard solution), thus eliminating the need for a compression unit. This novel layout achieves savings in both energy and investment in the equipment and machinery, as well as during operation (Figure 3).

[0043] Advantageously, one or more hydrogen-rich tail gases or fuel streams from a hydrogen purification unit, such as a PSA, may be sent to the fuel system either directly or after premixing with other streams (e.g., one or more CO2-depleted streams from a CO2 removal unit, or a portion of a hydrogen and nitrogen-rich stream leading to ammonia synthesis, after optionally further purification / separation).

[0044] The CO2 depletion stream from the CO2 removal unit can be partially recycled as reformer feed material and partially used as fuel. Optionally, the fuel portion can be separated from the stream. This can be optionally done using an overhead PSA to generate a CO2-containing stream that is recycled back into the inlet of the CO2 removal unit. The remaining tail gas stream from the overhead PSA may be partially used as fuel before being further separated in a second overhead PSA or membrane unit into a further hydrogen product stream, a hydrogen-rich fuel stream, and a carbon-rich recycling stream (which is sent to steps a) and / or b).

[0045] This lean process results in significant carbon emission reductions, with carbon capture rates ranging from approximately 90% to over 99%, making it an economical solution compared to commonly used methods for producing blue ammonia.

[0046] Preferred Embodiment 1. Follow these steps: a) A step of removing sulfur and other contaminants from the hydrocarbon supply material; b) Reforming the hydrocarbon stream from step a) to obtain synthesis gas containing CO, CO2, H2, H2O, and CH4; c) A shift reaction step to reduce the CO content; d) A first hydrogen purification step of stream (B) yielding hydrogen products (C), hydrogen-rich gas streams (D)(or more) and CO2-rich tail gas streams(or more), A method for producing ammonia, including, - The hydrogen-rich gas stream(D)(or more) is processed as fuel; - Nitrogen is added to the hydrogen product (C,L) to obtain a synthesis gas stream containing N2 and H2 for ammonia synthesis; and - The CO2-rich tail gas stream(s) is subjected to a CO2 removal step to yield a CO2 product(E) and a CO2 depletion stream(K), the CO2 product(s) are pressurized, and the CO2 depletion stream(s) are further purified in a second purification step, resulting in: i) The CO2-containing stream (J) is recycled to the CO2 removal inlet; ii) Stream (H) is divided into Stream (G) which is processed as fuel (g) and the remainder which is further processed in a third refining step; iii) The stream (F) from the third purification step is sent back to step a) or b), and / or iv) Stream (L), i.e., an optional hydrogen product stream from the third hydrogen purification step, is added to the hydrogen product (C) or is treated as an alternative fuel. The aforementioned method.

[0047] 1.1 The reformer used in step b) is preferably a self-thermal reformer (ATR), but may be any other suitable reformer.

[0048] 1.2 The gas from step b) is subjected to a shift reaction, where the CO content is preferably reduced to less than 4% by volume.

[0049] 1.3 The CO2-rich stream obtained after the CO2 removal step preferably contains more than 98% by volume of CO2 and can be stored or used in the production of other chemicals or fuels, such as urea, methanol, synthetic fuels or other suitable chemicals or fuels.

[0050] 1.4 The hydrogen-rich stream obtained in step d) preferably contains more than 93% by volume of H2 on a dry basis.

[0051] 1.5 The pressure applied in step d) of hydrogen purification is preferably 30-31 bar g(A).

[0052] 1.6 The L stream is a hydrogen product stream when the third purification unit is PSA, and a fuel stream when the third purification unit is a membrane.

[0053] 1.7 The method according to any one of the embodiments described above, wherein the hydrocarbon and carbon oxide content in the hydrogen-rich stream is less than 80 ppmv.

[0054] 1.8 The method according to any one of the above embodiments, wherein the CO2-rich tail gas contains more than 99.90%, preferably more than 99.95% by volume, and more preferably more than 99.98% by volume, hydrocarbons and carbon oxides in the gas emanating from the shift reaction.

[0055] 2. The method according to Embodiment 1, wherein the hydrogen-rich stream obtained from the hydrogen purification step contains more than 99.5% by volume of hydrogen, preferably more than 99.9% by volume.

[0056] If nitrogen is present in the feed material (B) for the hydrogen purification step (Figure 4), the nitrogen preferably passes through the first PSA together with the hydrogen product stream (C). The hydrogen purity of the hydrogen product stream decreases in proportion to the amount of nitrogen contained in the hydrogen product stream, and the product stream may contain approximately 97% or more hydrogen, for example, 97.86%.

[0057] In this optimized layout, nitrogen from the feed material passes through the PSA along with the hydrogen products. This means that the hydrogen product stream contains less hydrogen, but the layout is more efficient when it is necessary to obtain a higher hydrogen purity (approximately 99%) by separating nitrogen from the stream.

[0058] In particular, the increased nitrogen content in stream B preferably increases the nitrogen content in stream C without affecting other impurities, while maintaining a hydrogen purity of over 99% excluding nitrogen.

[0059] The first hydrogen purification step is carried out in either a PSA or a NWU.

[0060] 3. The method according to Embodiment 1 or 2, wherein a CO2 depletion stream (K) is sent to a second (hydrogen or CO2) purification unit to generate a CO2-rich recovery recycling stream (J) to a CO2 removal unit and a gas stream (H), the gas stream (H) is split between (i) a hydrogen-rich stream (G) and (ii) another hydrogen-rich stream, the hydrogen-rich stream (G) is treated as fuel (g), the other hydrogen-rich stream is sent to a third (hydrogen) purification unit, such as a PSA or membrane, to generate i) a carbon-rich tail gas recycling (F) and ii) a second hydrogen-rich stream (L), the carbon-rich tail gas recycling (F) is pressurized and sent to step a) or b), the second hydrogen-rich stream (L) is treated as fuel (g) if the third purification unit is a membrane, or as a hydrogen product stream if the third purification unit is a PSA.

[0061] Only a small amount of CO2 is introduced into the third PSA. This is therefore the hydrogen purification unit (PSA or membrane). Having an additional hydrogen product stream (L) allows for lower CAPEX because more hydrogen is recovered overall compared to the conventional layout.

[0062] At least one of the second and third hydrogen purification units is preferably a PSA, and more preferably an overhead PSA.

[0063] In the most preferred embodiment, both the second and third hydrogen purification units are overhead PSAs.

[0064] The method according to Embodiment 3, wherein at least one of the second and third hydrogen purification units is preferably an NWU.

[0065] 4. The CO2 product (E) obtained from the cryogenic CO2 removal step is pressurized (preferably by pumping) and supplied at the required pressure between 20 and 300 barg, preferably between about 140 and 190 barg.

[0066] 5. The method according to the above embodiment, wherein the CO2 product obtained from the cryogenic CO2 removal step is pumped to the required pressure.

[0067] 6. The method according to any one of Embodiments 1 to 3, wherein the CO2 product obtained from the PSA CO2 removal step is compressed to the required pressure.

[0068] 7. The method according to any one of the embodiments described above, wherein at least one of the hydrogen-rich tail gas streams (D)(or more) obtained from the hydrogen purification step is supplied directly to a fuel system. Alternatively, the one or more hydrogen-rich tail gas streams are premixed with other streams in the process before being supplied to the fuel system.

[0069] 7.1 The method according to any one of the embodiments described above, wherein a hydrocarbon fuel (e.g., CH4), a fuel stream G which is a split stream H from a second purification unit, a hydrogen-rich gas (D) from the hydrogen purification step, optionally treated as a fuel stream (L), and a portion of the hydrogen-rich stream optionally containing N2 and H2 for ammonia synthesis are premixed or supplied separately to a fuel system g).

[0070] 8. The method according to any one of the embodiments described above, comprising step b0) an adiabatic pre-reforming step of the hydrocarbon stream from step a) prior to step b), to obtain a synthesis gas containing CH4, CO, CO2, H2 and H2O.

[0071] 9. The method according to any one of the above embodiments, wherein the amount of air supplied to the air-blown secondary reformer is adjusted so that a specific molar ratio of N2 to H2 between 1:2.5 and 1:3.5 is obtained in the stream from the methane reactor.

[0072] 10. The method according to Embodiment 1, wherein the stream obtained from step d) contains N2 and H2 in a ratio of 1 to 3.0.

[0073] The method according to any one of the claims, wherein during and / or after the first purification step, streams C and D have the same composition.

[0074] 11. The following: a) Desulfurization section; b) Modification section; c) Shift section; d) The first hydrogen purification unit or section; e) CO2 removal unit or section; f) Second (hydrogen or CO2) purification section; g) A third (hydrogen) purification section (PSA or membrane); h) Ammonia synthesis section; i) Fuel system, and h) Tail gas compression section, A plant for producing ammonia according to the methods of claims 1 to X, including, - The first hydrogen purification unit is located upstream of the CO2 removal unit. - The second purification section is located downstream of the CO2 removal section. - The third purification unit (PSA or membrane) is located downstream of the second purification section, and - The tail gas compression section is included within the third purification section, The aforementioned plant.

[0075] The CO2 pressurization section (e.g., a pump) is located within the CO2 removal section.

[0076] 11.1. A plant for producing ammonia according to Embodiment 11, wherein the carbon content in the combined flue gas from the fuel system is less than 5%, preferably less than 1%, of the total carbon content in the hydrocarbon supply material and hydrocarbon fuel.

[0077] 11.2. The plant according to Embodiment 11, wherein the reforming section b) includes a self-heat reformer, or a tubular reformer followed by a self-heat reformer, or a tubular reformer followed by an air-blown secondary reformer.

[0078] 11.3. The plant according to Embodiment 11, wherein the shift section includes a high-temperature (HT) reactor, a medium-temperature (MT) reactor, a low-temperature (LT) reactor, or any combination of at least two of these.

[0079] The plant according to Embodiment 11.3, wherein two of the following are connected in series: i) an HT reactor, ii) an MT reactor, and / or iii) an LT reactor.

[0080] 11.5. The plant according to Embodiment 11 and any one of its subordinate embodiments, wherein the fuel system supplies fuel to a tubular reformer and / or a combustion heater and / or an auxiliary boiler and / or a gas turbine.

[0081] 11.6. The plant according to embodiment 11.5, wherein the fuel system includes one or more burners.

[0082] 12. The plant according to Embodiment 11 and any one of its subordinate embodiments, wherein the pressurizing section may include a compressor or pump or any other means suitable for pressurizing the CO2-rich tail gas.

[0083] 13. The plant according to Embodiment 11, wherein the hydrogen purification unit is one or more pressure swing adsorption (PSA) units.

[0084] 14. The plant according to Embodiment 11, wherein the hydrogen purification unit is another suitable unit or section for a similar purpose.

[0085] 15. The plant according to any one of embodiments 11 to 14, wherein the CO2 removal unit is cryogenic and includes a pressurized section.

[0086] 15.1 The plant according to embodiment 15, wherein the pressurized section contained within the CO2 cryogenic unit is a pump.

[0087] 16. The plant according to any one of embodiments 11 to 15, wherein the CO2 removal unit is a pressure swing adsorption (PSA) unit, a gas membrane, or other means suitable for the same or similar purpose.

[0088] 16.1 The plant according to any one of embodiments 11 to 16, wherein the CO2 depletion stream from the CO2 removal unit is further separated in one or more PSAs or membrane units into a) and / or a) carbon-containing recycling streams to be sent to the inlet of the CO2 removal unit, one or more hydrogen-rich fuel gas streams, and optionally further hydrogen product streams.

[0089] 17. The plant according to any one of embodiments 11 to 16, wherein the reforming section includes an HTER in parallel or in series with the ATR.

[0090] 18. The plant according to any one of embodiments 11 to 17, wherein the pre-reforming unit is located upstream of the reforming section.

[0091] 19. The plant according to any one of embodiments 11 to 18, wherein the fuel system g) includes one or more tubular reformers, combustion heaters, auxiliary boilers, and gas turbines.

[0092] 20. The plant according to embodiment 19, wherein the fuel system includes one or more burners.

[0093] 21. A plant for producing ammonia according to any one of Embodiments 11 to 20, wherein the carbon content in the combined flue gas from the fuel system g) is less than 5 volume percent, preferably less than 1 volume percent, of the total carbon content in the hydrocarbon supply material and hydrocarbon fuel.

[0094] 22. A plant according to any one of embodiments 11 to 21, wherein the reforming unit b) includes a self-heat reformer, or a tubular reformer followed by a self-heat reformer, or a tubular reformer followed by an air-blown secondary reformer. A tubular reformer is also known as a steam reformer.

[0095] 23. The plant according to any one of embodiments 11 to 22, wherein the shift section c) includes a high-temperature (HT) reactor, a medium-temperature (MT) reactor, or a low-temperature (LT) reactor, or any combination of at least two of these.

[0096] 24. Use of CO2 obtained by the method in Embodiment 1 for CO2 storage.

[0097] 25. Use of CO2 obtained by the method in Embodiment 1 for producing chemical substances, such as ammonia, urea, methanol, synthetic fuels, or other suitable chemical substances. [Examples]

[0098] example The layout in Figure 4 includes an oxygen combustion self-thermal reformer or ATR. In a given example, the amount of argon from the ASU is limited to 300 ppm argon in the oxygen from the ASU and 100 ppm argon in the nitrogen from the ASU. The pressure level at the front end and the low argon content in the feed material ensure high H2PSA efficiency. Due to the low argon content in the feed material, argon may be passed through the hydrogen product to obtain higher PSA efficiency. However, it is preferable that argon be maximized in the fuel stream(s), which is targeted at a given H2PSA efficiency and is determined by the overall fuel balance.

[0099] In the given example, the H2PSA efficiency is 91.3% (stream C + D). Stream D is used in the fuel adjustment ISBL to obtain the required carbon recovery rate from SOR to EOR. In this case, there are no export fuel requirements. Streams C and D have the same composition in the given example, but their compositions can be varied. - When the H2PSA efficiency (stream C+D) is optimally set with respect to the fuel balance, the argon distribution in the stream can be optimized. - For the entire H2 product stream (stream C+L), the following applies: The argon content should be minimized at a given H2PSA efficiency. • The nitrogen content can be maximized with a given H2PSA efficiency. The total amount of oxygen atoms (calculated as CO + H2O + 2*CO2 + 2*O2) must be less than 5 volumes ppm. - Stream G (one or more fuel streams): Hydrogen-rich fuel stream. Preferably, as much Ar as possible should be recovered in this stream. Pressure: 1.5 bar g is sufficient. The argon recovery rate should be maximized in the fuel stream(s). The hydrogen content should be maximized. • Carbon-containing components should be minimized. - Stream F: ATR recycling stream. High concentration of carbon components, with minimum amounts of N2, Ar, and H2 is preferred. The recovery rate of carbon-containing components should be maximized. • The content of hydrogen, nitrogen, and argon should be minimized.

[0100] Hydrogen product stream (stream C+L): A minimum amount of argon is preferred. (There is no target upper limit for argon; the amount of argon obtained in the hydrogen product can be handled in the loop by purging as needed). A maximum balance of N2 is preferred / optimal.

[0101] A layout with an H2PSA, a CO2 fractionation system, and two subsequent overhead PSAs has the advantage of obtaining a high H2 recovery fraction at a given pressure level with a low argon content in the feed material stream. This results in a reduction of the ATR recycling stream (F) and an overall reduction in the plant's front-end size, which in turn results in lower CAPEX, OPEX, and equalized ammonia costs compared to a layout with a purification system consisting of an amine-based CO2 removal unit and a nitrogen washing unit (NWU).

[0102] A high nitrogen content in natural gas supply materials for ammonia plants gives cryogenic solutions an advantage over NMU (where more nitrogen goes to recycled off-gas to ATR).

Claims

1. The following steps: a) A step of removing sulfur and other contaminants from hydrocarbon supply material; b) Modify the hydrocarbon stream from step a), CO, CO ２ H ２ H ２ O and CH ４ A step to obtain a synthesis gas containing; c) A shift reaction step to reduce the CO content; d) Hydrogen products (C), hydrogen-rich gas streams (D) (multiple), and CO ２ The first hydrogen purification step of the shifted stream (B) that results in a rich tail gas stream(s), A method for producing ammonia, including, - The hydrogen-rich gas stream (D) (or more) is treated as fuel; - Nitrogen is added to the hydrogen product (C,L) to produce N for ammonia synthesis. ２ and H ２ Obtain a synthesis gas stream containing; and - the CO ２ Rich tail gas stream(s) is / are subjected to a CO ２ removal step to yield a CO ２ product (E) and a CO ２ depleted stream (K), and the CO ２ depleted stream is further processed in a second purification step to provide a CO ２ rich recovery recycle stream (J) and a gas stream (H) to an CO removal inlet, and the gas stream (H) is split between (i) a hydrogen-rich stream (G) that is processed as fuel (g) and (ii) another hydrogen-rich stream, and the another hydrogen-rich stream is further processed in a third purification step to produce (i) a carbon-rich tail gas recycle (F) that is pressurized and sent to step a) or b), and (ii) a second hydrogen-rich stream (L), and any optional hydrogen product stream from the third hydrogen purification step is added to the hydrogen product (C) or alternatively processed as fuel.​​ The aforementioned method.

2. The method according to claim 1, wherein the hydrogen purity of the hydrogen product stream obtained from the hydrogen purification step decreases from more than 99% to more than 96% hydrogen, preferably more than 97% hydrogen, due to the presence of more nitrogen in the hydrogen product stream.

3. The aforementioned CO ２ Product (E) is cryogenic CO ２ The method according to claim 1 or 2, obtained from a removal step, pressurized, preferably by pumping, and supplied at a required pressure between 20 and 300 barg, preferably between about 140 and 190 barg.

4. The method according to any one of claims 1 to 3, wherein at least one of the hydrogen-rich tail gas streams (D)(or more) obtained from the hydrogen purification step is supplied directly to the fuel system either directly or after being mixed with other streams.

5. Hydrocarbon fuels (e.g., CH ４ ), fuel stream (G), which is a split stream of stream H from the second purification unit; hydrogen-rich gas (D) from the hydrogen purification step; optionally, treated as fuel stream (L); and N for ammonia synthesis. ２ and H ２ The method according to any one of claims 1 to 4, wherein a portion of the hydrogen-rich stream, optionally containing the above, is premixed or supplied separately to a fuel system g).

6. Before step b), adiabatic pre-reformation of the hydrocarbon stream from step a) step b ０ ) including step b ０ ) CH ４ CO, CO ２ H ２ and H ２ A method according to any one of claims 1 to 5, wherein a synthesis gas containing oxygen is obtained.

7. The stream obtained from step d) is N ２ and H ２ The method according to claim 1, comprising and in a ratio of 1 to 3.

0.

8. The method according to any one of claims 1 to 7, wherein the carbon content in the flue gas combined from the fuel system g) is less than 5 volume percent, preferably less than 1 volume percent, of the total carbon content in the hydrocarbon supply material and hydrocarbon fuel.

9. The method according to any one of claims 1 to 8, wherein during and / or after the first purification step, streams C and D have the same composition.

10. below: a) Desulfurization section; b) Modification section; c) Shift section; d) The first purification unit or section; e) CO ２ Removal unit or section; f) Second purification section; g) Third purification section; h) Ammonia synthesis section; i) Fuel system, and h) Tail gas compression section, A plant for producing ammonia according to the method of any one of claims 1 to 9, including - The first purification unit is the CO ２ Located upstream of the removal section, - The second purification section is the CO ２ Located downstream of the removal section, - The third purification unit is located downstream of the second purification section, and - The tail gas compression section is included within the third purification section, Furthermore, The aforementioned CO ２ The depleted stream (K) is processed in the second purification section, and (i) CO ２ CO into the inlet of the removal unit ２ (i) a rich recovery recycle stream (J) and (ii) a gas stream (H) are obtained, the gas stream (H) is split between (iii) a hydrogen-rich stream (G) which is processed as fuel (g) in the fuel system and (iv) another hydrogen-rich stream which is further processed in a third purification section, thereby generating v) a carbon-rich tail gas recycle (F) and vi) a second hydrogen-rich stream (L), the carbon-rich tail gas recycle (F) is pressurized in a tail gas compression section and sent back to step a) or b), the second hydrogen-rich stream (L) is processed as fuel (g) if the third purification unit is a membrane, and as a hydrogen product stream if the third purification unit is a PSA. The aforementioned plant.

11. The plant according to claim 10, wherein the reforming section b) includes a self-heat reformer, or a tubular reformer followed by a self-heat reformer, or a tubular reformer followed by an air-blown secondary reformer.

12. The plant according to claim 10 or 11, wherein the shift section includes a high-temperature (HT) reactor, a medium-temperature (MT) reactor, a low-temperature (LT) reactor, or any combination of at least two of these.

13. The plant according to claim 12, wherein two of the following are connected in series: i) an HT reactor, ii) an MT reactor, and / or iii) an LT reactor.

14. The plant according to any one of claims 10 to 13, wherein the fuel system provides fuel to a tubular reformer and / or a combustion heater and / or an auxiliary boiler and / or a gas turbine.

15. The plant according to any one of claims 10 to 14, wherein the fuel system includes one or more burners.

16. The plant according to any one of claims 10 to 15, wherein the first hydrogen purification section includes one or more pressure swing adsorption (PSA) units.

17. Both the second and third purification sections are overhead PSAs, and the second purification section is one or more hydrogen or CO2 ２ The plant according to any one of claims 10 to 16, comprising PSA, wherein the third purification section is one or more hydrogen PSAs or membranes.

18. The pressurizing section is a compressor or pump or the CO2 ２ Products or CO ２ The plant according to any one of claims 10 to 17, which may include any other means suitable for pressurizing rich tail gas.

19. The aforementioned CO ２ The plant according to any one of claims 10 to 18, wherein the removal section is cryogenic and includes a pressurized section or a tail gas compression section.

20. The pressure section is a pump, and cryogenic CO ２ The CO obtained from the unit ２ The plant according to any one of claims 10 to 19, wherein the product (E) is pressurized by pumping and supplied at a required pressure between 20 and 300 barg, preferably between about 140 and 190 barg.

21. The plant according to any one of claims 10 to 20, wherein the reforming section includes an HTER in parallel or in series with the ATR.

22. The plant according to any one of claims 10 to 21, wherein a pre-reforming unit is located upstream of the reforming section.

23. The plant according to any one of claims 10 to 22, wherein the fuel system g) includes one or more tubular reformers, combustion heaters, auxiliary boilers, and gas turbines.

24. The plant according to claim 23, wherein the fuel system includes one or more burners.

25. The plant according to any one of claims 10 to 24, wherein the reforming unit b) includes a self-heating reformer, or a tubular reformer followed by a self-heating reformer, or a tubular reformer followed by an air-blown secondary reformer.

26. The plant according to any one of claims 10 to 25, wherein the shift section c) includes a high-temperature (HT) reactor, a medium-temperature (MT) reactor, or a low-temperature (LT) reactor, or any combination of at least two of these.

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