Method for production of blue ammonia

Abstract

The present invention provides a method for producing blue ammonia, providing for a higher percentage of carbon capture. The method and system of the invention may be used in any ammonia plant.

Description

[0001] Title: Method for Production of Blue Ammonia

[0002] Field of Invention

[0003] The present invention provides a method and plant for producing blue ammonia, providing for a high percentage of carbon capture. The method and system of the invention may be used in any ammonia plant.

[0004] Background Art

[0005] Blue ammonia is a fossil fuel-based product produced with minimum emission of CO2 to the atmosphere. It is seen as a transition product between conventional fossil fuel-based ammonia and green ammonia produced from green or renewable power, water and air. The CO2 resulting from a blue ammonia production shall be stored permanently or converted into other chemicals. The main steps for producing blue ammonia are essentially the same as for producing conventional fossil fuel-based ammonia, the difference being that more of the carbon stemming from the carbon fuel is captured, providing a possibility for further processing.

[0006] The key here is that the blue ammonia does not release any carbon dioxide when used as fertilizer or burned. Currently available technology traps nearly all CO2 generated during the conversion process making this fuel one of the first carbon free fuel options for mass use. Blue ammonia is considered an environmentally friendly product which can be used until sufficient renewable or green power is available for producing green ammonia.

[0007] Over 60% of the CO2 can be captured from a natural gas-based ammonia plant because this is in the process gas (the byproduct of hydrogen production). Many ammonia plants already utilize this CO2 stream to produce urea or to sell as food grade CO2. The remaining CO2 emissions are in the much more dilute flue gas (the product of fuel combustion to preheat process streams). For some decades we have assumed we could capture most of this, but the lingering question has always been: how much of that CO2 in the flue gas is economically feasible to capture?

[0008] To meet net-zero targets, the CO2 capture rate should be as high as economically viable and as close to 100% as technically possible. However, a capture rate of 100% is still very challenging. The economic viability of residual emissions indirectly captured by a CDR, an absorption based and amine solvent based technology, will limit the capture rate to the range of 90-98%. In other words, it would be easier to capture that final two percent from air, as opposed to trying to capture it directly from the processed flue gas.

[0009] The present invention provides an economical way to achieve a high percentage of carbon capture up to more than 99% by wt by using carbon depleted fuel, mainly H2 and N2 and by recycling carbon containing off-gasses as addition feed streams. In this way the already available CO2 capture step in the ammonia process can be utilized to perform the complete CO2 capture.

[0010] Summary of Invention

[0011] The present invention provides a method for producing ammonia with a high percentage of carbon capture, up to more than 99% by wt, when compared to the prior art, where optimally between about 90-93% by wt of carbon capture is achieved. In addition, the present invention provides a method for reducing natural gas consumption and oxygen consumption by implementing an HTER-s in the reforming section. An ammonia plant within the scope of the present invention maybe be revamped or a new plant for production of ammonia. A revamped plant is an existing or traditional plant for production of ammonia where changes are made in order to, e.g. improve its operation, performance, economy or carbon emissions.

[0012] More than 99% CO2 recovery is enabled by reducing natural gas firing to be used for pilot burners, by using carbon depleted gases mainly H2 and N2 used as fuel for the fuel systems and by redirecting off-gases containing more than 60% Methane and / or CO to the reforming section or to the desulfurization section as additional feed gas.

[0013] Additionally, by the invention steam generation can be largely reduced and balance power (preferably green) can be imported, instead of generating power from produced steam inside battery limit (I BL) of the ammonia plant.

[0014] In this way natural gas feed and fuel are saved leading to improved natural gas consumption figures. This means for a given carbon capture rate that also less CO2 is generated compared to the standard solution. On the other hand, more import power is required. Since part of the reforming is taking place in the HTER-s this means that for the same ammonia production reforming in the ATR is reduced compared to standard layout, whereby oxygen consumption from an ASU is reduced.

[0015] Utility prices vary depending on plant / site location. For given specific utility prices it variates which blue ammonia layout becomes the most optimal and attractive. The present invention provides a beneficial alternative, when compared to a similar layout without HTER-s, when the natural gas price increases and / or power price reduces.

[0016] The method of the present invention provides the following advantages:

[0017] Can be applied for grass root plants and as revamps;

[0018] Utilize the already available CO2 capture step in the ammonia process to perform the complete CO2 capture;

[0019] Enables up to >99% wt CO2 capture;

[0020] Lower cost of operations, particularly when the natural gas price increases and / or power price reduces (Table 1);

[0021] Reduced natural gas consumption;

[0022] Reduced oxygen consumption from ASU;

[0023] Reduces the amount of flue gas thus reducing the NOx formations and thereby the NOx emission to the atmosphere.

[0024] Said advantages are provided by a set of features, comprising:

[0025] The reforming step comprises heat exchange reforming, by connecting an HTER in series (HTER-s) with an ATR in the reforming section; and

[0026] Reformed gas or process gas collected out of the ATR is processed in the heat exchange (HTER-s) reforming step where at least part of the carried heat is used.

[0027] Description of the Invention

[0028] Reducing CO2 emission has become a bound task in the chemical industry. Production of ammonia using hydrocarbons as feedstock inevitably results in CO2 formation which typically ends up in at least two CO2 containing process streams, one almost pure CO2 stream (1) extracted from the syngas cleaning section and one or more flue gas streams (2). The CO2 stream (1) can be utilized for further chemical processing or stored. The CO2 in the flue gas stream(s) (2) needs to be captured before it can find similar use.

[0029] It is well known that CO2 in the flue gas can be avoided by using carbon free fuels. In general, if hydrocarbons such as natural gas and carbon containing off gases originating from the process are used as fuels a post combustion carbon capture or recovery unit, a flue gas CDR can in these cases be applied for reducing the CO2 in the remaining flue gas.

[0030] One main advantage of this invention is that an HTER-s connected to an ATR (Fig. 1) is reducing the amount of flue gas, thereby reducing the CO2 content in the streams, reducing cost of operation in the ammonia plant.

[0031] Definitions

[0032] Autothermal Reforming (ATR) is the combined process of steam reforming and partial oxidation, a promising technology for low-cost and high-reliability hydrogen production. Compared to steam reforming, it is easier to operate with a smaller system, better temperature control, lower energy requirements, easier start-up, and less coking. In ATR, the reaction takes place in a single chamber where methane is partially oxidized. The reaction is exothermic due to the oxidation. The main difference between autothermal reforming and steam-methane reforming is that steam-methane reforming does not use or require oxygen. However, a major drawback of autothermal reforming is the large investment needed for an oxygen production plant, which simply becomes cost-effective only at high production capacities. Although air can be directly used instead of oxygen, the presence of inert nitrogen causes large gas volume and the system, therefore, requires larger equipment.

[0033] Generally, the autothermal reforming process is operated under adiabatic conditions and the product composition as well as the reaction temperature is governed by various operating parameters, e.g., preheat temperature of fuel, water, and air, pressure, fuel composition, heat loss, steam-to-carbon ratio, and air-to-carbon ratio. The suitable fuel for autothermal reforming is highly flexible, such as several gaseous hydrocarbons, e.g., methane, natural gas, LPG, as well as liquid hydrocarbons, e.g., gasoline, diesel, alcohols, naphtha, residual oil, ethylene glycol, and glycerol. An appropriate operation condition (e.g., catalysts, temperature, fuel / oxidant ratio, and treatment process) is strongly dependent on the fuel quality, i.e., the number of carbons and the purity of each fuel. The use of a heavy hydrocarbon fuel with some impurities can easily suppress the reforming performance because of coke formation and catalyst poisoning. Although less carbon deposition is usually observed in autothermal reforming compared to steam reforming, significant amounts of carbon deposition are still widely reported in the autothermal reforming of propane, butane, and gasoline even under steam-rich conditions. Sulfur, even at small amounts, can significantly reduce the catalyst service life. This can be avoided by installing a prereformer upstream the ATR. In the present invention, the process gas or reformed gas originated in the ATR can be used as heat source for partly reforming in a heat exchange reformer (HTER-s) connected in series with the ATR.

[0034] Blue Ammonia is ammonia that is created from using fossil fuel where at least 90% of the carbon in the fossil fuel is captured or recovered to be used in other products and processes or to be stored.

[0035] Carbon dioxide removal (CDR) methods cover either CO2 capture (or recovery or removal) from the synthesis gas (pre-combustion carbon capture) as well as CO2 capture (or recovery or removal) from the flue gas (post combustion carbon capture). In the present invention CDR refers to CO2 capture (or recovery or removal) from the flue gas (post combustion carbon capture (or recovery or removal). Capture, recovery or removal of CO2 is meant to mean the same in the present application.

[0036] Flash gas or process condensate means an intermediate gas stream obtained during CO2 capture step.

[0037] Flue gas according to the present invention means a mixture of combustion products including water vapor, carbon dioxide, particulates, heavy metals, and acidic gases obtained from combustion of fuels in one or more fired heaters used for process gas preheating and steam superheating.

[0038] Fuel section comprises fuel systems for supply of fuel to the combustion side of fired heaters and / or auxiliary boilers and / or gas turbines. Preferably, the fuel section comprises at least one waste heat section (WHS) or comprises one or more fired heaters. These systems comprise one or more burners in which the incoming fuel streams are burned together with air at variable temperature and pressure.

[0039] Hydrocarbon feed is any suitable hydrocarbon for ammonia production, preferably natural gas or methane.

[0040] Make-up gas is the synthesis gas stream obtained from the purification unit, before entering the ammonia loop or ammonia synthesis section (vii). Methanation means that the purification step is the conversion of carbon monoxide and carbon dioxide (CO2) to methane (CH4) through hydrogenation. The methanation reactions (equations 1 and 2) are exothermic and at normal operating temperatures (250-350°C) the equilibrium lies far to the right hand side.

[0041] (1) CO + 3H2<-> CH4+ H2O

[0042] (2) CO2+ 4H2CH4+ 2H2O

[0043] Using this route, the carbon monoxide and carbon dioxide impurities can be reduced to less than a few parts per million. The advantages of methanation, its simplicity and low cost, more than outweigh its disadvantages, hydrogen consumption and production of additional inerts in the makeup gas to the synthesis loop. Methanation can take place in a methanator or methanation section.

[0044] Nitrogen Wash or liquid nitrogen wash can be used as a final purification stage, delivering a gas to the ammonia synthesis loop that is free of all impurities, including inert gases. It is also the means for adding, in whole, or in part, the required nitrogen for ammonia synthesis. It is mainly used to purify and prepare ammonia synthesis gas within fertilizer plants. It is usually the last purification step upstream of ammonia synthesis. The liquid nitrogen wash has the function to remove residual impurities like CO, Ar and CH4from a crude hydrogen stream and to establish a stoichiometric ratio H21 N2of approximately 3:1. Carbon monoxide must be completely removed, since it is poisonous for the ammonia synthesis catalyst. Ar and CH4are inert components enriching in the ammonia synthesis loop. If not removed, a syngas purge or expenditures for purge gas separation are required. Raw hydrogen (hydrogen rich process stream) and high pressure nitrogen are fed to the liquid nitrogen wash unit. Both streams are cooled down against product gas. Feeding raw hydrogen to the bottom of the nitrogen wash column and some condensed nitrogen liquid to the top. Trace components are removed and separated as fuel gas. To establish the desired H2 / N2 ratio, high pressure nitrogen is added to the process stream. A nitrogen wash unit (NWU) is a unit or section where liquid nitrogen wash takes place.

[0045] Off-gases from one or more sections as the CO2 capture section, the hydrogen purification section or the ammonia recovery section are used in the present invention as fuel in the fired heater(s) or as recycle streams for additional feed streams in the desulphurization step (ii) or reforming step (iii). PSA means pressure swing adsorption, enables the energy-efficient recovery of specific compounds from a gas under pressure.

[0046] When excess steam is available at a plant, a pre-reformer can be installed at the reformer section for lowering the steam production, reducing the primary reformer or ATR and hence gas consumption. While also reducing energy consumption, in general, the installation of a pre-reformer can reduce the size of a primary reformer or ATR by up to 25%. The technology can also be used to increase the production capacity at no additional energy costs. Installing a pre-reformer at an existing plant will typically increase production by 10-20%. Other benefits of the technology include the increased flexibility in terms of feedstock going to the steam reformer or ATR and the increased lifetime of the steam reformer or ATR and shift catalysts, as practically all sulphur in the hydrocarbon feed and process steam is absorbed by the prereforming catalyst.

[0047] Steam reforming is the key process in the formation of syngas for ammonia and methanol production. The reforming section is normally the largest, most expensive and most energy intensive piece of equipment on these plants and efficient and reliable operation is key to the performance of the whole plant. The reforming section comprises one or more reformers, arranged in series or in parallel. Optionally the reforming section may comprise a pre-reformer upstream the HTER-s.

[0048] The shift step is the reaction of synthesis gas with steam in a reaction zone to convert carbon monoxide into a raw gas mixture including carbon dioxide and hydrogen. At the outlet of steam reformers, HTER and ATR, said syngas contains H2, CO, CO2, CH4 and water in chemical equilibrium at high temperatures in the approximate range of 700 to 1050 °C depending on the process pressure and the mixture of feed stock and process steam or water. By means of the CO shift conversion an important portion of the CO content in the synthesis / process gas is used for additional hydrogen generation, which is following the chemical reaction

[0049] CO + H2O <=> H2+ CO2

[0050] This process is exothermic and is limited by the chemical equilibrium. There are three different versions of CO shift conversion: (i) High temperature (HT) CO shift conversion at about 320 to 450 °C down to approx. 3.5 % CO on dry basis at the reactor outlet; (ii) Medium temperature (MT) CO shift conversion at about 190 to 330 °C down to approx. 0.8 % CO on dry basis at the reactor outlet; and (iii) Low temperature (LT) CO shift conversion at about 180 to 230 °C down to approx. 0.3 % CO on dry basis at the reactor outlet.

[0051] The application of the low temperature CO shift conversion is normally installed downstream of the HT shift at already reduced CO content in the feed gas. In the present invention the shift section (c) may comprise a high temperature shift, a medium temperature shift and / or a low- temperature shift and preferably the shift conversion is carried out in two stages, wherein a high temperature shift (HTS) catalyst is used as the first stage and typically converts over 80% of the CO, followed by use of a low temperature shift catalyst (LTS) that converts the majority of the remaining CO.

[0052] The synthesis gas from the ATR contains 25-30% (dry gas base) of CO (SynCOR layout). In the shift section, most of the CO will be converted to CO2.The performance of the shift conversion is very important for enabling a high carbon capture rate. The conversion reaction is conducted in two steps with heat removal steps in between. The synthesis gas exiting the low temperature shift converter is cooled and after most of the steam is condensed and removed it passes through the CO2 capture section. Heat released during cooling and condensation can be used for other purposes such as the regeneration of the CO2 scrubbing unit.

[0053] Preferred embodiments

[0054] 1 . Process for producing ammonia comprising the steps of: i) preheating a hydrocarbon feed; ii) removing sulphur and other contaminants from the preheated hydrocarbon feed; iii) reforming the preheated hydrocarbon feed comprising heat exchange reformer (HTER-s) in series with an autothermal reformer, wherein the preheated hydrocarbon feed is added to the tube side of the HTER-s and partly reformed, the partly reformed hydrocarbon feed is subsequently passed to the autothermal reformer for producing of synthesis gas comprising CO, CO2, H2, H2O and CH4, the synthesis gas is used to provide heat on the shell side of the heat exchange reformer ; iv) sending the synthesis gas through one or more shift reaction steps reducing the CO content; v) sending the CO depleted synthesis gas to a CO2 capture step where it is split in at least a CO2 rich stream and a hydrogen rich stream, and optionally a flash gas stream; vi) sending the hydrogen rich stream through a purification step, wherein nitrogen is added to the hydrogen rich stream within the purification step or just after to the purified hydrogen rich stream for generating an ammonia synthesis gas stream; vii) sending at least a part of the ammonia synthesis gas stream from step (vi) through an ammonia synthesis section, where it is converted to ammonia.

[0055] 2. The process of embodiment 1 , wherein a part of said purified hydrogen rich stream or part of said synthesis gas stream is used as fuel in one or more fired heater(s).

[0056] 3. The process of anyone of the preceding embodiments, wherein at least a part of the off gases removed from the purification step v) and / or vi) are compressed and sent to step ii) or iii) for further increase of the carbon capture.

[0057] 4. The process of embodiment 1 , wherein one or more carbon containing off gas stream(s) from step v) and / or vi) are sent to one or more fired heater(s) and wherein at least one of the fired heaters is equipped with a unit which removes 80% or more, preferably 90% or more, preferably 95% or more, preferably 98% or more CO2 from the resulting flue gas obtained by using flue gas carbon capture.

[0058] 5. Process according to anyone of embodiments 1 to 4 wherein the carbon dioxide removal section in step (v) comprises one or more amine-based CO2removal units.

[0059] 6. Process according to anyone of embodiments 1 to 4 wherein the carbon dioxide removal section in step (v) comprises one or more hot-potassium carbonate-based CO2removal units.

[0060] 7. The process of anyone of the preceding embodiments, wherein the nitrogen is added in step (vi) by a nitrogen wash in the purification step.

[0061] 8. The process of anyone of embodiments 1 to 6, wherein the purification step (vi) comprises one or more PSA(s) or one or more PSA(s)+one or more membrane(s), the purified stream is split into a hydrogen rich product stream to which nitrogen is added for synthesis gas generation and a hydrogen rich fuel stream.

[0062] 9. The process of anyone of embodiments 1 to 4, wherein the CO depleted synthesis gas from step (iv) is sent to a PSA where it is split in a hydrogen product stream to which nitrogen is added for synthesis gas generation, in hydrogen rich fuel stream(s) and in a CO2 rich tail gas stream, which is sent to a cryogenic CO2 capture step where it is split in at least a CO2 rich stream and an off gas stream which is further purified in one or more PSA and / or one or more membranes into carbon containing stream(s) which are recycled back to (ii) or (iii) and the CO2 capture step, hydrogen rich fuel stream(s) and optional additional hydrogen product stream.

[0063] 10. The process of anyone of embodiments 1 to 6, wherein the purification step (vi) comprises methanation, the purified stream is split into a hydrogen rich product stream to which nitrogen is added for synthesis gas generation and a hydrogen rich fuel stream.

[0064] 11. Process according to any one of the preceding embodiments comprising an adiabatic prereforming step of the preheated hydrocarbon stream from step ii), before step iii), wherein a synthesis gas comprising CH4, CO, CO2, H2 and H2O is obtained

[0065] 12. Process according to any of the preceding embodiments, wherein the steam / carbon ratio in the reforming step including optional prereforming step is 2.6 — 0.1 , 2.4 — 0.1 , 2 — 0.2, 1.5 — 0.3 or 1 .4 — 0.4, such as 1 .4 or 1 or, 0.6.

[0066] 13. Process according to any of the preceding embodiments, wherein the preheated hydrocarbon stream is partly reformed in the HTER-s to a CH4 slip in the HTER-s tube side outlet stream of 20% - 60%, preferably 30% - 50%, preferably 35% - 45%.

[0067] 14. Process according to any of the preceding embodiments wherein steam is added to the outlet stream of the autothermal reformer and sent to the HTER-s shell side. The steam / total carbon ratio (total carbon from CH4, CO and CO2) inlet the HTER-s shell side is 0.9-2.4, preferably 1.5-2.3, preferably 1.6-2.2.

[0068] 15. Process according to any of the preceding embodiments, wherein preheating of one or more process streams and / or steam superheating is performed by one or more electrical heaters.

[0069] 16. Process according to any of the preceding embodiments, wherein the autothermal reformer in step (iii) is replaced by an electrical reformer wherein the steam / carbon ratio is 1.1 -2.5, preferably 1.2-2.2, preferably 1.3-2.1. 17. Process according to any of the preceding embodiments, wherein the steam generation system is based on HP steam generation in the front-end and the loop or MP steam generation in the front end and the loop. The steam system requires either a HP +LP steam header system or a MP+LP header system.

[0070] The HTER-s is partly or fully bypassed on tube and / or shell side. The HTER-s can be fully bypassed on tube and shell side during start up. During normal operation partly bypass of the HTER-s on tube and / or shell side is applied / allows for temperature regulation and adjustment for loss of catalyst activity. Bypass range at start of run (SOR) is 3%-12% , preferably 5%- 10%, preferably 7%-10%. Bypass range at end of run (EOR) is 2%-11%, preferably 3-9%.

[0071] Brief Description of Drawings

[0072] Figure 1) shows the proposed layout using an optional prereformer followed by a HTER-(s) and an autothermal reformer ATR in the reforming section and a nitrogen wash unit in the purification section: a) Desulphurization bo) Pre-reforming bi) Reforming (HTER-s) b2) Reforming (ATR) c) Shift section d) CO2 capture section e) Purification section (e.g. nitrogen wash unit) f) Ammonia synthesis section g) Fuel section (e.g. one or more fired heaters) h) off gas recycle compression section

[0073] Example 1

[0074] Table 1 shows the benefits of the proposed layout, in terms of consumption figures for a carbon capture or CO2 recovery of 95%. For a SynCOR ammonia plant - ATR based ammonia plant without doing any attempt to make it to a blue process a carbon capture rate of 87% can be obtained. Up to 95% carbon capture can be obtained without the need of recycling carbon containing off-gases to the desulphurization section and / or reforming section but simply by using carbon depleted fuel, mainly H2 and N2. For higher carbon capture up to more than 99% recycling of carbon containing off-gases are required.

[0075] A SynCOR based ammonia layout with 95% carbon capture is shown in the first column as base case. Advantageously, the present invention provides the layout in the last column to the right in Table 1 also with a carbon capture rate of 95% , showing that lower natural gas feed and fuel consumption (92.7%) and lower oxygen consumption from the ASU (79.5%) are obtained by implementing an HTER-s in the layout.

[0076] In addition, due to lower natural gas feed consumption lower amounts of CO2 emitted (94.4%) and CO2 captured (92.7%) are obtained for fulfilling 95% carbon capture.

[0077] It is also seen that the overall consumption figures including power (98.6%) is beneficial for the proposed layout with HTER-s, despite the higher power consumption (145%) required in this case.

[0078] The present invention provides a beneficial alternative, when compared to a similar layout without HTER-s, when the natural gas price increases and / or power price reduces.

[0079] Table 1

Claims

Claims1 . Process for producing ammonia comprising the steps of: i) preheating a hydrocarbon feed; ii) removing sulphur and other contaminants from the preheated hydrocarbon feed; iii) reforming the preheated hydrocarbon feed comprising heat exchange reformer (HTER-s) in series with an autothermal reformer, wherein the preheated hydrocarbon feed is added to the tube side of the HTER-s and partly reformed, the partly reformed hydrocarbon feed is subsequently passed to the autothermal reformer for producing of synthesis gas comprising CO, CO2, H2, H2O and CH4, the synthesis gas is used to provide heat on the shell side of the heat exchange reformer ; iv) sending the synthesis gas through one or more shift reaction steps reducing the CO content; v) sending the CO depleted synthesis gas to a CO2 capture step where it is split in at least a CO2 rich stream and a hydrogen rich stream, and optionally a flash gas stream; vi) sending the hydrogen rich stream through a purification step, wherein nitrogen is added to the hydrogen rich stream within the purification step or just after to the purified hydrogen rich stream for generating an ammonia synthesis gas stream; vii) sending at least a part of the ammonia synthesis gas stream from step (vi) through an ammonia synthesis section, where it is converted to ammonia.

2. The process of claim 1 , wherein a part of said purified hydrogen rich stream or part of said synthesis gas stream is used as fuel in one or more fired heater(s).

3. The process of anyone of the preceding claims, wherein at least a part of the off gases removed from the purification step v) and / or vi) are compressed and sent to step ii) or iii) for further increase of the carbon capture.

4. The process of anyone of the preceding claims, wherein one or more carbon containing off gas stream(s) from step v) and / or vi) are sent to one or more fired heater(s) and wherein at least one of the fired heaters is equipped with a unit which removes 80% or more, preferably 90% or more, preferably 95% or more, preferably 98% or more CO2 from the resulting flue gas obtained by using flue gas carbon capture.

5. Process according to anyone of claims 1 to 4, wherein the carbon dioxide removal section in step (v) comprises one or more amine-based CO2removal units.

6. Process according to anyone of claims 1 to 4, wherein the carbon dioxide removal section in step (v) comprises one or more hot-potassium carbonate-based CO2removal units.

7. The process of anyone of the preceding claims, wherein the nitrogen is added in step (vi) by a nitrogen wash in the purification step.

8. The process of claims 1 to 6, wherein the purification step (vi) comprises one or more PSA(s) or one or more PSA(s) + one or more membrane(s), the purified stream is split into a hydrogen rich product stream to which nitrogen is added for synthesis gas generation and a hydrogen rich fuel stream.

9. The process of claims 1 to 4, wherein the CO depleted synthesis gas from step (iv) is sent to a PSA where it is split in a hydrogen product stream to which nitrogen is added for synthesis gas generation, hydrogen rich fuel stream(s) and in a CO2 rich tail gas stream, which is sent to a cryogenic CO2 capture step where it is split in at least a CO2 rich stream and an off gas stream which is further purified in one or more PSA and / or one or more membranes into carbon containing stream(s) which are recycled back to (ii) or (iii) and the CO2 capture step, hydrogen rich fuel stream(s) and optional additional hydrogen product stream.

10. The process of claims 1 to 6, wherein the purification step (vi) comprises a methanator, the purified stream is split into a hydrogen rich product stream to which nitrogen is added for ammonia synthesis gas generation and a hydrogen rich fuel stream.11 . Process according to any one of the preceding claims comprising an adiabatic prereforming step of the preheated hydrocarbon stream from step (ii), before step (iii), wherein a synthesis gas comprising CH4, CO, CO2, H2 and H2O is obtained12. Process according to any of the preceding claims, wherein the steam / carbon ratio in the reforming step including optional prereforming step is 2.6 — 0.1 , 2.4 — 0.1 , 2 — 0.2, 1.5 — 0.3 or 1.4 — 0.4, such as 1 .4 or 1 or, 0.6.

13. Process according to any of the preceding claims, wherein the preheated hydrocarbon16 stream is partly reformed in the HTER-s to a CH4 slip in the HTER-s tube side outlet stream of 20%-60%, preferably 30% - 50%, preferably 35%-45%.

14. Process according to any of the preceding claims, wherein steam is added to the outlet stream of the autothermal reformer and sent to the HTER-s shell side. The steam / total carbon ratio (total carbon from CH4, CO and CO2) inlet the HTER-s shell side is 0.9-2.4, preferably 1.5-2.3, preferably 1.6-2.2.

15. Process according to any of the preceding claims, wherein preheating of one or more process streams and / or steam superheating is performed by one or more electrical heaters.

16. Process according to any of the preceding claims, wherein the autothermal reformer in step (iii) is replaced by an electrical reformer wherein the steam / carbon ratio is 1.1 -2.5, preferably 1.2-2.2, preferably 1.3-2.1.

17. Process according to any of the preceding claims, wherein the steam generation system is based on HP steam generation in the front-end and the loop or MP steam generation in the front end and the loop. The steam system requires either a HP +LP steam header system or a MP+LP header system.

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