Method for producing a synthesis gas product containing hydrogen

Abstract

1. A method for producing a synthesis gas product comprising hydrogen from an endothermic decomposition reaction of an ammonia feedstream, the method comprising: - providing an ammonia feedstream; - performing a catalytic conversion by catalytically converting the ammonia feedstream by endothermically decomposing the ammonia feedstream into a synthesis gas product comprising hydrogen; - performing a heat exchange step by exchanging heat between the synthesis gas product and the catalytic conversion of the ammonia feedstream, the heat exchange step comprising: - delivering the synthesis gas product to a synthesis gas product circulation duct, the duct being positioned for heat exchange between the delivery synthesis gas product and the catalytic conversion of the ammonia feedstream; - recovering heat from the delivery synthesis gas product; and - directing the recovered heat to the catalytic conversion of the ammonia feedstream.

Description

[Technical Field]

[0001] The field of the invention is that of processes for producing synthesis gas products. In particular, the invention relates to processes for producing synthesis gas products comprising hydrogen. Furthermore, the invention relates to reactors for producing synthesis gas products comprising hydrogen from an ammonia feed stream. Furthermore, the invention relates to the use of such reactors for ammonia decomposition. [Background technology]

[0002] The production of a synthesis gas product containing hydrogen by the endothermic decomposition of an ammonia feed stream can be carried out in a catalytic unit at high temperatures (typically 400°C to 800°C). Such units typically include a metal shell, a catalyst, and an external heat source. To achieve the lowest possible carbon dioxide emissions for the decomposition process, the external heat source is provided solely by combustion of the ammonia feed stream in a furnace. The process requires large amounts of heat and energy. A drawback of such a process is the large amount of fuel required to provide the high energy levels for the decomposition reaction. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention proposes a method for producing a synthesis gas product containing hydrogen from an ammonia feedstock that significantly reduces the external energy requirements.

[0004] To this end, the present invention provides a process for producing a synthesis gas product comprising hydrogen from an endothermic decomposition reaction of an ammonia feedstream, the process comprising: providing an ammonia feed stream; - performing a catalytic conversion by catalytically converting an ammonia feed stream by endothermic decomposition of said ammonia feed stream into a synthesis gas product comprising hydrogen; - performing a heat exchange step by performing a heat exchange between the synthesis gas product and a catalytic conversion of an ammonia feed stream, said heat exchange step comprising: delivering the synthesis gas product to a synthesis gas product circulation duct, the duct being positioned for heat exchange between the delivery synthesis gas product and catalytic conversion of an ammonia feed stream; recovering heat from the outgoing syngas product; directing recovered heat to the catalytic conversion of the ammonia feed stream; and We propose a method including:

[0005] According to one embodiment of the invention, the catalytic conversion is carried out in a reaction chamber.

[0006] According to one aspect of the invention, the previously disclosed steps are carried out in a reactor configured to produce a synthesis gas product comprising hydrogen.

[0007] According to one aspect of the invention, the method includes a conditioning step of the ammonia feed stream, which conditioning step follows the ammonia feed stream supplying step.

[0008] According to one aspect of the present invention, a catalytic conversion converts an ammonia feed stream conditioned in a conditioning step into a synthesis gas product comprising hydrogen.

[0009] The synthesis gas product comprises hydrogen and nitrogen. In particular, the synthesis gas product comprises hydrogen, nitrogen, and an unconverted portion of the ammonia feed stream. In other words, the synthesis gas product comprises hydrogen, nitrogen, and an unconverted portion of the ammonia feed stream that has not been converted by catalytic conversion of the ammonia feed stream.

[0010] According to one aspect of the invention, the method includes discharging a synthesis gas product from the reactor.

[0011] According to one aspect of the invention, the method includes a step of treating the synthesis gas product after the step of releasing the synthesis gas product. The treatment step can be, for example, a purification step.

[0012] According to one aspect of the invention, the treating step is a purification step after the release step, which purification step uses methods such as pressure swing adsorption (acronym PSA), cryogenic separation, membranes, temperature swing adsorption (acronym TSA), etc.

[0013] According to one aspect of the invention, the ammonia conditioning step undergoes evaporation, preheating and / or superheating.

[0014] According to one aspect of the invention, heat for evaporation, preheating and / or superheating during the ammonia conditioning step is provided by an external heat source (eg, external combustion resulting from a combustion reaction).

[0015] According to one embodiment of the invention, the catalytic conversion is carried out at a temperature comprised between 600°C and 900°C, preferably between 700°C and 800°C.

[0016] Alternatively, the catalytic conversion is carried out at a temperature comprised between 300°C and 600°C, preferably between 400°C and 500°C.

[0017] According to one embodiment of the invention, the catalytic conversion is carried out at a pressure of about 25 bar (absolute).

[0018] According to one embodiment of the present invention, the catalytic conversion is carried out in the presence of a catalyst that promotes the catalytic conversion.

[0019] According to one aspect of the invention, the catalytic conversion is at least partially heated by an external heat source, for example, heat from an external combustion resulting from a combustion reaction.

[0020] According to one embodiment of the invention, the combustion reaction is a reaction between a fuel gas (eg, ammonia) and combustion air.

[0021] According to one aspect of the invention, during the heat exchange step, the outgoing syngas product circulates in a syngas product circulation duct contained in a heat exchanger located in the reaction chamber, and thus the outgoing syngas product exchanges heat with the catalytic converter as the outgoing syngas product circulates in the syngas product circulation duct.

[0022] The present invention further provides a reactor for producing a synthesis gas product comprising hydrogen from an ammonia feedstream, the reactor comprising: a shell tube containing a reaction chamber, the reaction chamber being configured to be heated; an active catalyst layer disposed in the reaction chamber; an inlet for an ammonia feed stream disposed in the reaction chamber, the inlet for the ammonia feed stream being in fluid communication with the catalyst bed; at least one heat exchanger disposed in heat exchange relationship with the reaction chamber; The present invention relates to a reactor comprising:

[0023] According to one aspect of the present invention, the heat exchanger is disposed within the reaction chamber, and the reactor is configured such that after the ammonia feed stream enters the reaction chamber, the ammonia feed stream flows through the catalyst bed for catalytically converting at least a portion of the ammonia feed stream into a synthesis gas product in the catalyst bed, and the synthesis gas product flows through the heat exchanger, the heat exchanger being disposed within the reaction chamber in a heat exchange relationship with the catalyst bed and the ammonia feed stream. In other words, the reactor includes a set of volumes for circulating the ammonia feed stream through the catalyst bed and for allowing the synthesis gas product to flow through the heat exchanger.

[0024] In one embodiment of the invention, the reactor is configured so that the ammonia feed stream circulates through the catalyst bed and the synthesis gas product flows through the heat exchanger countercurrent to the circulation in the catalyst bed.

[0025] According to one aspect of the invention, the shell tube includes a tube inlet for an ammonia feed stream, the inlet for the ammonia feed stream configured to allow the ammonia feed stream to enter the shell tube.

[0026] According to one aspect of the invention, the shell tube includes a synthesis gas product outlet configured to discharge the synthesis gas product from the reactor.

[0027] According to one aspect of the invention, the heat exchanger includes at least one syngas product circulation duct arranged for delivering the syngas product, the syngas product circulation duct including a wall arranged for heat exchange between the delivered syngas product and the reaction chamber.

[0028] According to one aspect of the invention, the syngas product circulation duct is arranged for heat exchange between the outgoing syngas product and the catalyst bed.

[0029] According to one aspect of the invention, the heat exchanger includes at least one inlet configured to supply the synthesis gas product to the heat exchanger after catalytic conversion of the ammonia feed stream.

[0030] According to one aspect of the invention, the heat exchanger includes at least one outlet configured to deliver the synthesis gas product from the heat exchanger.

[0031] According to one aspect of the invention, the synthesis gas product duct is a heat exchange coil.

[0032] According to one embodiment of the invention, the heat exchanger comprises two synthesis gas product circulation ducts as described above.

[0033] According to one aspect of the present invention, the heat exchanger includes two heat exchange coils, which are interlocked.

[0034] According to one embodiment of the present invention, the shell tube is divided into a reaction chamber and an outlet chamber by a separation tray. Therefore, a different (preferably lower) pressure can be set in the outlet chamber than in the reaction chamber. In one embodiment of the present invention, the outlet chamber is configured to receive the synthesis gas product after it has circulated through the heat exchanger. In other words, the outlet chamber is configured to receive the synthesis gas product before the release step.

[0035] According to one aspect of the invention, the shell tube is configured to be fluidly connected to a collection chamber for the synthesis gas product, the collection chamber being fluidly connected to an outlet chamber of the shell tube. In one aspect of the invention, the collection chamber is configured to receive the synthesis gas product and to discharge the synthesis gas product.

[0036] According to one aspect of the invention, the heat exchanger is disposed within the catalyst bed.

[0037] According to one embodiment of the present invention, the catalyst layer is a catalyst bed.

[0038] According to one embodiment of the present invention, the catalyst layer is a dump catalyst bed of solid catalyst.

[0039] According to one embodiment of the present invention, the catalyst layer is a structural catalyst. Here, the structural catalyst can be disclosed as a catalyst coated on a structure (particularly a non-porous structure), for example, on the inner wall of a shell tube.

[0040] According to one embodiment of the invention, the catalyst is configured to promote catalytic conversion at temperatures comprised between 600°C and 900°C, preferably between 700°C and 800°C.

[0041] Alternatively, the catalyst is configured to promote catalytic conversion at temperatures comprised between 300°C and 600°C, preferably between 400°C and 500°C.

[0042] According to one embodiment of the present invention, the catalyst comprises at least one component selected from nickel, ruthenium, cobalt, cobalt-molybdenum or iron as catalytically active material, in particular nickel as catalytically active material on a support (e.g., an aluminum oxide (Al2O3) support).

[0043] According to one aspect of the invention, the heat exchanger is formed from nickel-containing stainless steel (e.g., alloy 600, alloy 625), nickel-coated steel, nickel-coated aluminum, or another catalytic material containing nickel. Such materials can promote ammonia conversion to hydrogen and nitrogen and avoid nitride formation.

[0044] According to one aspect of the invention, the inner wall of the shell tube is configured to be protected from nitride formation.

[0045] According to one aspect of the present invention, the inner wall of the shell tube is centrifugally cast.

[0046] According to one embodiment of the present invention, the inner wall of the shell tube is a microalloy wall.

[0047] According to one aspect of the invention, the inner wall of the shell tube comprises a material selected from G4852, Micro R, and HT_E, and the inner wall of the shell tube is optionally aluminized or coated with a build-up.

[0048] According to one aspect of the present invention, the inner wall of the shell tube does not include a corrosion-protection layer, which eliminates the problem of metal dusting causing corrosion.

[0049] According to one aspect of the invention, the reaction chamber is configured to be heated externally. The external heat can be provided by a combustion process (e.g., a combustion reaction).

[0050] According to one aspect of the invention, the heat exchanger is configured to recover heat from catalytic conversion in the reaction chamber and direct the recovered heat to the reaction chamber (particularly the catalyst layer).

[0051] The present invention further relates to the use of a reactor as described above for producing a synthesis gas product comprising hydrogen from an ammonia feed stream in an endothermic reaction of ammonia decomposition.

[0052] Furthermore, the present invention relates to a furnace for decomposing ammonia, comprising at least one reactor as described above and at least one heating device for heating the reactor.

[0053] According to one aspect of the invention, the furnace comprises multiple reactors and / or multiple heating devices, as described above.

[0054] According to one embodiment of the invention, the reactors are fluidly arranged parallel to one another.

[0055] Further features, details and advantages of the invention will become more clearly apparent on reading the following description, given by way of example only and with reference to the drawings, in which: [Brief explanation of the drawings]

[0056] [Figure 1] FIG. 1 is a schematic representation of the method of the present invention. [Figure 2] FIG. 2 is a schematic diagram of a reactor according to a first embodiment of the invention. [Figure 3] FIG. 3 is a schematic diagram of a reactor according to a second embodiment of the invention. [Figure 4] FIG. 4 is a schematic diagram of a furnace including the reactor of FIG. 2 or FIG. DETAILED DESCRIPTION OF THE INVENTION

[0057] It should first be noted that the drawings disclose the invention in detail for carrying out the invention, and these drawings naturally serve to define the invention more clearly, if necessary.

[0058] FIG. 1 illustrates a process 100 for producing a synthesis gas product comprising hydrogen from an ammonia feedstream, the process comprising: a step 101 of providing an ammonia feed stream; conditioning 102 the ammonia feed stream; performing a catalytic conversion 103 by catalytically converting the ammonia feed stream by endothermically decomposing the ammonia feed stream into a synthesis gas product comprising hydrogen; - performing a heat exchange step by performing a heat exchange between the synthesis gas product and a catalytic conversion of an ammonia feed stream, said heat exchange step comprising: Step 109 of delivering the synthesis gas product to a synthesis gas product circulation duct, the duct being arranged for heat exchange between the delivery synthesis gas product and catalytic conversion of an ammonia feed stream; recovering heat from the outgoing syngas product 104; 105 directing recovered heat to catalytic conversion of the ammonia feed stream; and a step 106 of externally heating the catalytic conversion; - a step 107 of discharging the synthesis gas product from the reactor; - treating a synthesis gas product reactor; 1 shows a method 100 including:

[0059] Steps 101, 103, 104, and 105 are performed in a reactor configured to produce a synthesis gas product comprising hydrogen.

[0060] Here, the conditioning step 102 may be, for example, but not limited to, vaporization of the ammonia feed stream.

[0061] Here, the step 103 of catalytic conversion of the ammonia feed stream is carried out at a temperature comprised between 600°C and 900°C, preferably between 700°C and 800°C.

[0062] This catalytic conversion is a decomposition reaction of an ammonia feed stream, an endothermic reaction that requires heat, and is carried out in the presence of an active catalyst that promotes the conversion of the ammonia feed stream during the decomposition reaction, where heat is supplied to the catalytic conversion.

[0063] The method includes a step 106 of external heating of the catalytic conversion. This external heating can come from external combustion. Here, "external" means that the external heat is not supplied from the reactor. This external heating is achieved, for example, by combustion of a fuel gas containing ammonia and combustion air. Heat is transferred from this combustion to the catalytic conversion by convection, conduction, and radiation. However, external heating can also come from Joule heating by an electric heating device.

[0064] After catalytic conversion, the synthesis gas product contains hydrogen, nitrogen, and possibly a portion of the unconverted ammonia feedstock. Synthesis gas is the product of the endothermic decomposition reaction of ammonia. Thus, "synthesis gas product" refers to the cracked gas product containing hydrogen and nitrogen. The synthesis gas product is hot due to the heat provided to the catalytic conversion.

[0065] The method includes a step 104 of recovering heat from the outgoing syngas product. This step is an internal heat recovery step. The method then includes a step 105 of directing the recovered heat from the syngas product. During this step, the outgoing syngas product circulates in heat exchange relationship with a catalytic conversion of an ammonia feed stream to transfer the heat of the outgoing syngas product to the catalytic conversion (particularly the catalyst). These two steps allow for a reduction in external heating, and consequently, a reduction in the amount of flue gas required.

[0066] The method includes a synthesis gas product discharge step 107. During this step, the synthesis gas product is discharged from the reactor where catalytic conversion takes place, for processing in a processing step 108, if necessary. For example, this processing step can be a purification step, which uses classical purification methods (e.g., PSA), cryogenic separation, membranes, TSA, etc. Thus, purified hydrogen is obtained.

[0067] FIG. 2 is a schematic diagram of a reactor for producing a synthesis gas product comprising hydrogen from an ammonia feed stream according to a first embodiment.

[0068] In this embodiment, reactor 9 includes a shell tube 4, which is pressurized. Shell tube 4 includes reaction chamber A, which provides catalytic conversion of the ammonia feed stream, which catalytic conversion is a decomposition reaction.

[0069] The shell tube includes an ammonia feed stream tube inlet 10, which is configured to allow the ammonia feed stream to enter the shell tube 4 (more precisely, reaction chamber A).

[0070] Reaction chamber A contains a layer 5 of active solid catalyst (here, a dump bed of active catalyst) configured to promote the catalytic conversion of ammonia (here, a decomposition reaction) to a synthesis gas product containing hydrogen at a pressure of about 25 bar (absolute) and a temperature comprised between 600°C and 900°C, preferably between 700°C and 800°C. The catalyst layer is, for example, a nickel-containing catalyst. The ammonia feed stream circulates over active catalyst layer 5 where the decomposition reaction occurs. This reaction is possible at high temperatures, thereby contributing heat 7, 6 to reaction chamber A.

[0071] Shell tube 4 (more precisely, reaction chamber A) now includes heat exchanger 8, which is disposed within reaction chamber A in heat exchange relationship with active catalyst layer 5 and the ammonia feed stream. In this embodiment, heat exchanger 8 includes a single synthesis gas product circulation duct (here, tube) formed of a heat-conducting material such as a metal alloy (e.g., alloy 600). In another embodiment, not shown here, the heat exchanger includes at least two tubes formed of this heat-conducting material. Reactor 9 is configured, after entering reaction chamber A via inlet 1, to have the ammonia feed stream flow through active catalyst layer 5 for decomposition reaction of at least a portion of the feed stream into a synthesis gas product at active catalyst layer 5, and have the synthesis gas product flow through a circulation duct included in the heat exchanger, which is disposed within reaction chamber A.

[0072] The catalyst bed 5 is configured to be partially heated by external heat 7 from an external heat source. The external heat source is, for example, external combustion or electrical heating. Thus, the ammonia feed stream is converted into a synthesis gas product containing hydrogen. The ammonia feedstock is heated and this heat is provided to the decomposition reaction. The already decomposed gas is then further heated. When the hot gas synthesis product flows through the synthesis gas product circulation duct of the heat exchanger 8, it transfers heat 6 internally to the catalyst bed 5. Thus, the catalyst bed is heated by the external heat source 7 and the internal heat source 6. Thus, the heat consumption of the external heat 7 is reduced. In a preferred embodiment, the synthesis gas product flows through the heat exchanger 8 in countercurrent.

[0073] The shell tube includes an outlet for the synthesis gas product 3 positioned to discharge the synthesis gas product from the reactor.

[0074] FIG. 3 is a schematic diagram of a reactor for producing a synthesis gas product comprising hydrogen from an ammonia feed stream according to a second embodiment.

[0075] In this embodiment, reactor 14 includes a shell tube 11 containing a reaction chamber A', which is configured to be heated. The reactor includes an active catalyst bed 12 disposed within reaction chamber A'. Catalyst bed 12 is configured to promote the decomposition reaction of an ammonia feed stream into a synthesis gas product. The ammonia feed stream circulates through catalyst bed 12 at a pressure of 25 bar (absolute) and a temperature comprised between 600°C and 900°C, where the catalyst includes nickel as a catalytically active material.

[0076] The reactor 14 includes a heat exchanger 13 arranged to perform heat exchange between the synthesis gas product and the decomposition reaction in the reaction chamber A', where the heat exchanger 13 includes two heat exchange coils 16, 17, which are coupled together.

[0077] As shown in FIG. 2, the catalyst bed 12 is configured to be partially heated by external heat 14 from an external heat source. The external heat source is, for example, external combustion or electrical heating. Thus, the ammonia feed stream is converted into a synthesis gas product containing hydrogen. The ammonia feed is heated, and this heat is provided to the decomposition reaction through the heat exchanger inlet. The already decomposed gas is then further heated. When the hot gas synthesis product flows through the synthesis gas product circulation duct of the heat exchanger 13, the hot gas synthesis product transfers heat 15 internally to the catalyst bed 12. Thus, the catalyst bed is heated by the external heat source 14 and the external heat source 15. Thus, the heat consumption of the external heat 15 is reduced. In a preferred embodiment, the synthesis gas product flows countercurrently through the heat exchanger 13.

[0078] The reactors of Figures 2 and 3 can be used for the decomposition reaction of an ammonia feed stream.

[0079] 4 is a schematic diagram of a furnace for decomposing ammonia that includes multiple reactors 201, such as those disclosed in FIGS. 2 and 3, in a combustion chamber 203. The furnace 200 includes multiple burners 202 configured to generate flames and heat the reactors 201. In this embodiment, the reactors are fluidly arranged parallel to one another.

Claims

1. 1. A method (100) for producing a synthesis gas product comprising hydrogen from an endothermic decomposition reaction of an ammonia feedstream, comprising: - providing an ammonia feed stream (101); - carrying out a catalytic conversion (103) by catalytically converting said ammonia feed stream by endothermically decomposing said ammonia feed stream into a synthesis gas product comprising hydrogen; - performing a heat exchange step by performing a heat exchange between said synthesis gas product and said catalytic conversion of said ammonia feed stream, said heat exchange step comprising: - delivering (109) said synthesis gas product to a synthesis gas product circulation duct, said duct being arranged for said heat exchange between said delivery synthesis gas product and said catalytic conversion of said ammonia feed stream; recovering heat from the outgoing syngas product (104); directing the recovered heat to the catalytic conversion of the ammonia feedstream; and A method (100) comprising:

2. The method (100) of claim 1, wherein the catalytic conversion (103) is carried out at a temperature comprised between 600°C and 900°C, preferably between 700°C and 800°C.

3. 3. The method (100) of claim 1 or 2, wherein the catalytic conversion (103) is carried out in a reaction chamber.

4. The method (100) of any one of claims 1 to 3, wherein the catalytic conversion (103) is at least partially heated by an external heat source, for example heat from an external combustion resulting from a combustion reaction.

5. The method (100) of any one of claims 1 to 4, wherein the outgoing syngas product circulates in the syngas product circulation duct contained in a heat exchanger located within the reaction chamber.

6. A reactor (9, 14) for producing a synthesis gas product comprising hydrogen from an ammonia feed stream, comprising: a shell tube (4, 11) containing a reaction chamber (A, A'), said reaction chamber (A, A') being adapted to be heated; - an active catalyst layer (5, 12) placed in said reaction chamber (A, A'), an inlet for the ammonia feed stream located in the reaction chamber, the inlet for the ammonia feed stream being in fluid communication with the reaction chamber; at least one heat exchanger (8, 13) arranged in heat exchange relationship with said reaction chamber; a reactor (9, 14) containing

7. 7. The reactor (9, 14) of claim 6, wherein the heat exchanger (8, 13) is disposed within the reaction chamber (A, A'), and the reactor (9, 14) is configured such that after the ammonia feed stream enters the reaction chamber, the ammonia feed stream flows through the catalyst bed (5, 12) for catalytic conversion of at least a portion of the feed stream to a synthesis gas product in the catalyst bed (5, 12), and the synthesis gas product flows through the heat exchanger (8, 13), and the heat exchanger is disposed within the reaction chamber (A, A') in a heat exchange relationship with the catalyst bed (5, 12) and the ammonia feed stream.

8. 8. The reactor (9, 14) of claim 6 or 7, configured so that the ammonia feed stream circulates through the catalyst bed (5, 12) and the synthesis gas product flows countercurrently through the heat exchanger (8, 13).

9. The reactor (9, 14) according to any one of claims 6 to 8, wherein the shell tube (4, 11) comprises a tube inlet for the ammonia feed stream, the tube inlet being configured to allow the ammonia feed stream to enter the shell tube (4, 11).

10. The reactor (9, 14) according to any one of claims 6 to 9, wherein the heat exchanger (8, 13) comprises at least one synthesis gas product circulation duct arranged for delivering the synthesis gas product, the synthesis gas product circulation duct comprising a wall arranged for heat exchange between the synthesis gas product and the reaction chamber.

11. 11. The reactor (9, 14) according to any one of claims 6 to 10, wherein the heat exchanger (8, 13) comprises at least one inlet configured to supply the synthesis gas product to the heat exchanger (8, 13) after the catalytic conversion of the ammonia feed stream.

12. The reactor (9, 14) according to any one of claims 6 to 11, wherein the heat exchanger (8, 13) comprises at least one outlet, the outlet being configured to deliver the synthesis gas product from the heat exchanger (8, 13).

13. Use of the reactor according to any one of claims 6 to 12 in the endothermic reaction of ammonia decomposition.

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