Method for producing a hydrogen-containing pyrolysis gas product

Abstract

A process for the production of a hydrogen-containing cracked gas product from the endothermic cracking reaction of an ammonia feed stream, said process comprising the following steps: - recovering heat from the cracked gas product flowing in a cracked gas duct (23) in a heat recovery step; - redirecting the recovered heat to at least one secondary reactor comprising a gas reaction section in which a secondary endothermic catalytic conversion of the ammonia feed stream into a partially converted ammonia stream is carried out, in a heat redirection step; - transferring the redirected heat to the secondary endothermic catalytic conversion by means of a heat-conducting layer at least partially delimiting the gas reaction section, in a heat transfer step, the process comprising: - carrying out a heat exchange step by means of heat exchange between the cracked gas product and the primary endothermic catalytic conversion.

Description

Technical Field

[0001] This invention relates to an apparatus for producing hydrogen-containing cracked gas products through an endothermic reaction of an ammonia feedstock. This invention also relates to a method for producing hydrogen-containing cracked gas products. Background Technology

[0002] The production of hydrogen-containing cracked gas products from an endothermic cracking reaction of an ammonia feedstock stream can be carried out in a catalytic unit at elevated temperatures, typically 400°C to 800°C. Such a unit typically comprises a metal casing, a catalyst, and an external heat source. To achieve the lowest possible CO2 footprint for the cracking process, the external heat source is provided solely by the combustion of the ammonia fuel stream in the furnace. Heat is transferred to the catalyst that promotes the cracking reaction, which requires a significant amount of heat and energy to facilitate the reaction. If the temperature is too low for the catalyst to promote the cracking reaction, the ammonia conversion rate is significantly reduced. This low conversion rate necessitates a higher process load in the catalytic unit, resulting in increased waste heat in the endothermic cracking effluent, which in turn increases the generation and output of byproduct vapors. The generation of byproduct vapors can be a result of cooling the effluent, such as thermally cracked gases from a cracking reaction involving elevated temperatures. Summary of the Invention

[0003] This invention proposes a method and apparatus for producing hydrogen-containing cracked gas products from an endothermic cracking reaction of an ammonia feedstock, wherein the required external energy is significantly reduced and the conversion rate of the cracking reaction is significantly improved.

[0004] This invention proposes a method for producing hydrogen-containing cracked gas products from an endothermic cracking reaction of an ammonia feedstock, the method comprising the following steps:

[0005] -Provide ammonia feedstock;

[0006] - The main reactor is heated during the heating step;

[0007] - In the heated main reactor, the partially converted ammonia stream is converted into cracked gas products through a main endothermic catalytic conversion.

[0008] - In the heat recovery step, heat is recovered from the pyrolysis gas product flowing in the pyrolysis gas pipeline;

[0009] - In the heat redirection step, the heat recovered in the heat recovery step is redirected to at least one secondary reactor, which includes a gas reaction section in which a secondary endothermic catalytic conversion of the ammonia feedstock to the partially converted ammonia stream is carried out.

[0010] - In the heat transfer step, the redirected heat is transferred to the secondary endothermic catalytic conversion via a thermally conductive layer that at least partially defines the gas reaction section.

[0011] The method includes:

[0012] - A heat exchange step is performed by exchanging heat between the cracked gas product and the primary endothermic catalytic conversion, the heat exchange step comprising the following steps:

[0013] - The cracked gas product is discharged in the cracked gas pipeline, which is arranged for heat exchange between the discharged cracked gas product and the main endothermic catalytic conversion;

[0014] -Recover heat from the discharged cracked gas products;

[0015] - The recovered heat is directed to the main endothermic catalytic conversion.

[0016] In this disclosure, the primary endothermic catalytic conversion can also be referred to as the primary catalytic conversion, and the secondary endothermic catalytic conversion can also be referred to as the secondary catalytic conversion.

[0017] Arranging the cracked gas pipeline in a heat-exchange connection with both the primary and secondary catalytic conversions allows for particularly efficient thermal integration, enabling the recovery of waste heat from the cracked gas. In this configuration, the waste heat from the cracked gas can be recovered almost immediately after the cracked gas leaves the primary catalytic conversion and directed back to the primary catalytic conversion to directly promote it. Remaining waste heat in the cracked gas can be used to promote the secondary catalytic conversion. Zero steam output can be achieved in this process.

[0018] In one embodiment, the heat exchange step is performed upstream of the heat recovery step on the pyrolysis gas pipeline.

[0019] According to one aspect of the invention, the main catalytic conversion is carried out in a reaction chamber.

[0020] In one aspect of the invention, the main endothermic catalytic conversion is the main cracking reaction of the partially converted ammonia stream.

[0021] In one aspect of the invention, the primary catalytic conversion and the secondary catalytic conversion are carried out sequentially in the direction of the ammonia feedstock flow.

[0022] In one aspect of the invention, the secondary catalytic conversion is located upstream of the main catalytic conversion in the direction of ammonia feedstock flow. The ammonia feedstock is converted into a partially converted ammonia stream through the secondary endothermic catalytic conversion, and the partially converted ammonia stream is converted into cracked gas products through the main endothermic catalytic conversion.

[0023] In one aspect of the invention, the partially converted ammonia stream is a pre-cracked ammonia feedstock stream.

[0024] In one aspect of the invention, the secondary catalytic conversion is a pre-cracking reaction of the ammonia feedstock stream.

[0025] The cracked gas product contains unconverted portions of hydrogen, nitrogen, and potential ammonia.

[0026] In one embodiment, the method includes the step of recovering hydrogen from the pyrolysis gas product, for example by adsorption, particularly by pressure swing adsorption.

[0027] In one aspect of the invention, the secondary catalytic conversion is carried out at a conversion rate similar to that of the primary catalytic conversion, preferably at a conversion rate lower than that of the primary catalytic conversion.

[0028] In one aspect of the invention, the secondary catalytic conversion rate is in the range of 15% to 90%, preferably in the range of 15% to 50%, and more preferably in the range of 15% to 20%.

[0029] In one aspect of the invention, the secondary catalytic conversion is carried out at a lower temperature than the primary catalytic conversion.

[0030] In one aspect of the invention, the secondary catalytic conversion is carried out at a temperature of 350°C to 650°C, preferably about 550°C, and the primary catalytic conversion is carried out at a temperature of 600°C to 900°C, preferably 700°C to 800°C, for example at an absolute pressure of about 30 bar (30 barA). The lower temperature of the secondary catalytic conversion allows the use of a different catalyst than that used in the primary catalytic conversion, which requires a lower temperature to function, thereby increasing the overall conversion of the cracking reaction.

[0031] In one aspect of the invention, the primary catalytic conversion is carried out in a primary reactor in the presence of a catalyst layer, while the secondary catalytic conversion is carried out in a secondary reactor in the presence of a secondary catalyst.

[0032] In another aspect of the invention, the secondary catalyst has a composition different from that of the catalyst layer.

[0033] In one aspect of the invention, the primary catalytic conversion and the secondary catalytic conversion are carried out in their respective separate catalyst beds.

[0034] According to one aspect of the invention, the catalyst layer comprises nickel as a catalytically active material, particularly as a catalytically active material on a support such as alumina (Al2O3).

[0035] According to one aspect of the invention, the catalyst layer comprises 5% to 20% by weight of nickel, preferably about 15% by weight of nickel.

[0036] According to one aspect of the invention, the secondary catalyst comprises nickel as a catalytically active material, particularly as a support, such as an alumina (Al2O3) support.

[0037] According to one aspect of the invention, the secondary catalyst comprises 20% to 45% by weight, preferably 35% by weight, of nickel and / or a noble metal as a catalytically active material, such as ruthenium, preferably 1.5% by weight or more of ruthenium.

[0038] In one aspect of the invention, the method includes a preheating step of a partially converted ammonia stream upstream of the main catalytic conversion.

[0039] In one aspect of the invention, the secondary reactor is a gas-heated reactor.

[0040] In one aspect of the invention, the heating step includes burning the fuel gas stream in a combustion reaction taking place in the combustion chamber.

[0041] In one aspect of the invention, the heating step includes heating the main reactor by means of an electric heating device.

[0042] In one aspect of the invention, the step of discharging the pyrolysis gas product from the pyrolysis gas pipeline includes discharging the pyrolysis gas product from the reaction chamber into the pyrolysis gas pipeline. Specifically, the heat recovery step includes recovering heat from the pyrolysis gas product discharged from the reaction chamber into the pyrolysis gas pipeline.

[0043] In one aspect of the invention, the heat recovery step and the heat redirection step are carried out by convective heat transfer from the pyrolysis gas product to the secondary reactor.

[0044] In one aspect of the invention, convective heat transfer occurs through the movement of pyrolysis gas products toward the heat-conducting layer and the fluid around the heat-conducting layer.

[0045] In one aspect of the invention, the heat transfer step is carried out by heat conduction from the pyrolysis gas product through the heat-conducting layer to the gas reaction section.

[0046] In one aspect of the invention, the pyrolysis gas pipeline includes a pyrolysis gas product circulation section arranged in a heat exchange relationship with the gas reaction section, through which the pyrolysis gas product circulates.

[0047] According to one aspect of the invention, the secondary reactor is a single-pass reactor. In other words, the ammonia feedstock is circulated only once through the gas reaction section. This is advantageous for filling the secondary reactor with a secondary catalyst.

[0048] According to one aspect of the invention, the ammonia feed stream is unidirectionally circulated in a secondary reactor.

[0049] According to one aspect of the invention, the generation of byproduct vapors during the catalytic conversion process is reduced. Preferably, the output of byproduct vapors during the catalytic conversion process is avoided.

[0050] This invention also relates to an apparatus for producing hydrogen-containing cracked gas products through an endothermic cracking reaction of an ammonia feedstock, the apparatus comprising:

[0051] - At least one main reactor is arranged to produce the cracked gas product by main endothermic catalytic conversion of a partially converted ammonia stream;

[0052] - A pyrolysis gas pipeline is arranged to discharge the pyrolysis gas product from the main reactor;

[0053] - A secondary reactor comprising a gaseous reaction section including a secondary catalyst configured to facilitate the secondary endothermic catalytic conversion of the ammonia feedstock to a partially converted ammonia stream. The gaseous reaction section is at least partially defined by a thermally conductive layer arranged to recover heat from the cracked gas products in the cracked gas pipeline and provide the recovered heat to the secondary catalyst.

[0054] -The main reactor includes:

[0055] - Outer casing tube, including a reaction chamber configured to be heated;

[0056] -A catalyst layer arranged in the reaction chamber for the main endothermic catalytic conversion;

[0057] - An inlet for the ammonia stream used for partial conversion, located in the reaction chamber, is fluidly connected to the catalyst bed.

[0058] In the device, the pyrolysis gas pipeline is arranged to exchange heat with the reaction chamber.

[0059] In one aspect of the invention, the apparatus includes a heating device arranged to provide heat to the main reactor, particularly to the reaction chamber.

[0060] In one embodiment, a portion of the pyrolysis gas conduit extends within the reaction chamber. Specifically, the apparatus is configured to, after the partially converted ammonia stream enters the reaction chamber, allow the partially converted ammonia stream to flow through a catalyst layer for catalytic conversion into the pyrolysis gas product, and allow the pyrolysis gas product to flow through the pyrolysis gas conduit.

[0061] In one embodiment, a cracked gas conduit extends through the catalyst layer.

[0062] In one embodiment, the device is configured to cause the partially converted ammonia stream to flow through the catalyst layer in a countercurrent manner to the flow of the cracked gas product through a cracked gas conduit extending in the reaction chamber.

[0063] In one embodiment, the portion of the pyrolysis gas conduit extending into the reaction chamber includes a heat exchange section arranged in a heat exchange relationship with the reaction chamber. Specifically, the heat exchange section includes at least one heat exchange tube arranged for the circulation of the pyrolysis gas product and for heat exchange between the pyrolysis gas product and the reaction chamber. In one embodiment, the heat exchange tube has a coiled / helical shape.

[0064] In one embodiment, the heat exchange section includes at least two heat exchange tubes arranged for circulation of the pyrolysis gas product and heat exchange between the pyrolysis gas product and the reaction chamber. In one embodiment, each of the at least two heat exchange tubes has a coiled helical shape. In particular, the at least two heat exchange tubes with coiled helical shapes are staggered / interlaced.

[0065] In one aspect of the invention, the secondary reactor is arranged upstream of the main reactor along the flow direction of the ammonia feedstock.

[0066] In one aspect of the invention, the apparatus includes a conduit for a partially converted ammonia stream, which is arranged to discharge the partially converted ammonia stream from a secondary reactor and to feed the discharged partially converted ammonia stream into a main reactor.

[0067] In one aspect of the invention, the catalyst layer is configured to promote the main catalytic conversion.

[0068] In one aspect of the invention, the main catalyst is configured to allow the partially converted ammonia stream to undergo main catalytic conversion at a temperature of 600°C to 900°C, preferably 700°C to 800°C, for example at a pressure of about 30 barA.

[0069] In particular, the catalyst layer contains nickel as a catalytically active material, especially as a catalytically active material on a support such as alumina (Al2O3).

[0070] According to one aspect of the invention, the catalyst layer comprises 5% to 20% by weight of nickel, preferably about 15% by weight of nickel.

[0071] In one aspect of the invention, the secondary catalyst is configured to allow the ammonia feedstock stream to undergo secondary catalytic conversion at a temperature of 350°C to 650°C, preferably about 550°C, for example at a pressure of about 30 barA.

[0072] According to one aspect of the invention, the secondary catalyst comprises nickel as a catalytically active material, particularly as a catalytically active material on a support such as alumina (Al2O3).

[0073] According to one aspect of the invention, the secondary catalyst comprises 20% to 45% by weight, preferably 35% by weight, of nickel and / or a noble metal as a catalytically active material, such as ruthenium, preferably 1.5% by weight or more of ruthenium.

[0074] In one aspect of the invention, the apparatus includes a feedstock conduit arranged to feed ammonia feedstock to a secondary reactor.

[0075] In one aspect of the invention, the thermally conductive layer is configured for heat transfer to the secondary endothermic catalytic conversion.

[0076] In one aspect of the invention, the heating device includes a combustion chamber configured for burning a fuel gas stream.

[0077] In one aspect of the invention, the heating device includes an electric heating device.

[0078] In one aspect of the invention, the heat-conducting layer is arranged to recover a portion of the heat from the cracked gas product stream in the cracked gas pipeline, particularly from the cracked gas product stream discharged from the main reactor.

[0079] In one aspect of the invention, the cracked gas pipeline includes a cracked gas circulation section arranged in a heat-exchange relationship with a gas reaction section. Specifically, the gas reaction section is separated from the cracked gas circulation section by a heat-conducting layer. In other words, the heat-conducting layer is arranged for heat exchange between the ammonia feedstock stream and the cracked gas product from the main endothermic catalytic conversion.

[0080] In particular, the pyrolysis gas circulation section includes circulation pipes or circulation pipe bundles arranged for the circulation of pyrolysis gas products.

[0081] Specifically, the gas reaction section includes a housing filled with a secondary catalyst, and at least a circulation pipe or circulation pipe bundle extends within the housing.

[0082] According to one aspect of the invention, the gas reaction section includes a circulation pipe or circulation tube bundle filled with a secondary catalyst, and the cracked gas circulation section includes a cracked gas circulation housing through which the circulation pipe or circulation tube bundle extends.

[0083] In one embodiment, the pyrolysis gas circulation section is arranged downstream of the heat exchange section on the pyrolysis gas pipeline.

[0084] In one aspect of the invention, the catalyst layer and / or secondary catalyst are selected from particulate catalysts of structured catalysts.

[0085] The present invention also relates to the use of the above-mentioned equipment for producing hydrogen-containing cracked gas from an endothermic cracking reaction of an ammonia feedstock stream. Attached Figure Description

[0086] Other features, details, and advantages of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0087] Figure 1 This is a schematic diagram of the device of the present invention according to one embodiment;

[0088] Figure 2 This is a schematic diagram of the main reactor of the present invention according to the first embodiment;

[0089] Figure 3 This is a schematic diagram of the main reactor of the present invention according to the second embodiment. Detailed Implementation

[0090] First, it should be noted that the accompanying drawings disclose the invention in a detailed manner for implementing the invention, and the drawings can, of course, be used to more clearly define the invention if necessary.

[0091] The method of the present invention for producing hydrogen-containing cracked gas products from an endothermic cracking reaction of an ammonia feedstock includes the following steps:

[0092] -Provide ammonia feedstock;

[0093] - The main reactor is heated in a heating step by using a fuel gas stream to burn into a combustion reaction effluent gas stream, wherein the combustion takes place in a combustion chamber;

[0094] - In the heated main reactor, the partially converted ammonia stream is converted into the cracked gas product through a main endothermic catalytic conversion.

[0095] -Recover heat from the pyrolysis gas products in the heat recovery step;

[0096] - The recovered heat is then directed to a secondary reactor, where the ammonia feedstock undergoes secondary endothermic catalytic conversion.

[0097] - In the heat transfer step, the redirected heat is transferred to the secondary endothermic catalytic conversion through a thermally conductive layer that at least partially defines the gas reaction section.

[0098] The secondary catalytic conversion is a pre-cracking reaction. In this case, the secondary catalytic conversion is located upstream of the main catalytic conversion in the direction of the ammonia feedstock flow, and the ammonia feedstock flow is converted into a partially converted ammonia flow through the secondary catalytic conversion. The partially converted ammonia flow is then converted into cracked gas products through the main endothermic catalytic conversion.

[0099] Here, the secondary catalytic conversion is carried out at a temperature of 350°C to 650°C, preferably about 550°C, and the primary catalytic conversion is carried out at a temperature of 600°C to 900°C, preferably 700°C to 800°C, for example, at a pressure of about 30 barA. The lower temperature of the secondary catalytic conversion allows the use of a different catalyst than that used in the primary catalytic conversion, thereby improving the extent of the cracking reaction.

[0100] The conversion rate of the secondary catalytic conversion is in the range of 15% to 90%, preferably in the range of 15% to 50%, and even more preferably in the range of 15% to 20%. The conversion rate of the primary catalytic conversion is around 93%.

[0101] The main catalytic conversion takes place in the presence of an active catalyst layer, which promotes the conversion of the ammonia stream partially converted during the cracking reaction when heat is supplied to the catalytic conversion. The catalyst layer contains nickel as a catalytically active material, particularly as a catalytically active material on a support such as alumina (Al2O3). The catalyst layer contains 5% to 20% by weight of nickel, preferably about 15% by weight of nickel.

[0102] The secondary catalytic conversion is carried out in the presence of a secondary catalyst that promotes the conversion of the ammonia feedstock into a partially converted ammonia stream during the pre-cracking reaction. The secondary catalytic conversion is conducted in a secondary reactor in the presence of a secondary catalyst comprising nickel as a catalytically active material, particularly as a catalytically active material on a support such as alumina (Al₂O₃). The secondary catalyst contains 20% to 45% by weight of nickel, preferably 35% by weight, and / or a noble metal, such as ruthenium, preferably 1.5% by weight or more. The use of noble metals is advantageous because the feedstock primarily contains ammonia with impurity levels below ppm.

[0103] The secondary catalytic conversion takes place in a secondary reactor, which is a secondary reactor heated by cracked gas. The cracked gas pipeline 23 is configured to discharge the cracked gas product from the main reactor and distribute the cracked gas product around the cracked gas heated secondary reactor to recover heat and guide the heat from the cracked gas pipeline 23 to the secondary catalytic conversion.

[0104] Following the primary catalytic conversion, the cracked gas product comprises hydrogen, nitrogen, and a portion of unconverted ammonia feedstock. The cracked gas product is hot due to the heat supplied to the catalytic reaction. The method here includes a step of recovering heat from the cracked gas product and a step of directing the recovered heat to a secondary catalytic conversion in a secondary reactor, referred to as a cracked gas heated secondary reactor. In this step, the cracked gas product circulates in the cracked gas heated secondary reactor and exchanges heat with the ammonia feedstock stream, which is also circulating in the same reactor. For example, the cracked gas product circulates in a first section of the heat exchanger, and the ammonia feedstock stream circulates in another section of the heat exchanger, the first and second sections being separated by a thermally conductive layer that allows heat exchange between the two fluids.

[0105] The method of the present invention includes a secondary reaction carried out in a secondary reactor heated by cracked gas and a secondary reaction carried out in a secondary reactor heated by cracked gas, the secondary reactor including a heat exchanger for exchanging heat between cracked gas products and ammonia feed stream.

[0106] The method may further include the step of controlling the fuel gas flow rate based on the feedstock flow rate. When the ammonia feedstock flow rate decreases, the fuel gas flow rate also decreases. Therefore, the flow rate is controlled to obtain the desired temperatures in the primary and secondary catalytic conversions, and thus the desired cracked gas product yield.

[0107] The method also includes steps for regulating the ammonia feedstock flow, such as a gasification step of the ammonia feedstock flow.

[0108] This method includes the step of discharging the pyrolysis gas product. If necessary, the pyrolysis gas product discharged from the main reactor can be processed in a treatment step. For example, this treatment step could be a purification step. This purification step uses classic purification methods such as PSA, cryogenic separation, membrane, or TSA. Purified hydrogen is thus obtained.

[0109] Figure 1 This is a schematic diagram of a device according to one embodiment.

[0110] In this embodiment, equipment 1 is used to produce hydrogen-containing cracked gas products through an endothermic cracking reaction of an ammonia feedstock stream, the equipment comprising:

[0111] - At least one main reactor 2 is arranged to produce hydrogen-containing cracked gas products by main endothermic catalytic conversion of a partially converted ammonia stream.

[0112] - Heating device, here combustion chamber 4, is arranged to provide heat to main reactor 2;

[0113] - Pyrolysis gas conduit 23, which is arranged to discharge the pyrolysis gas stream from the main reactor;

[0114] - Secondary reactor 3, comprising a gas reaction section 21 arranged for generating a partially converted ammonia stream through secondary endothermic catalytic conversion of the ammonia feedstock stream, the gas reaction section 21 being at least partially defined by a thermally conductive layer 22 arranged for recovering some heat from the cracked gas product in the cracked gas conduit 23 and providing the recovered heat to the secondary catalytic conversion, the gas reaction section 21 including a secondary catalyst configured to promote the secondary catalytic conversion of the ammonia feedstock stream.

[0115] For example, a main reactor extends through the combustion chamber used for burning the fuel gas stream. There may be multiple main reactors extending through the combustion chamber.

[0116] In this embodiment, the secondary reactor 3 is arranged upstream of the main reactor 2 along the flow direction of the ammonia feed stream. The apparatus 1 includes an ammonia feed stream inlet 9, which is arranged for the inlet of the ammonia feed stream. The apparatus 1 includes a partially converted ammonia conduit, which is arranged to distribute the partially converted ammonia stream from the secondary catalytic conversion (pre-crack reaction) carried out in the secondary reactor 3 to the main reactor 2.

[0117] The secondary reactor 3, heated by the cracked gas, includes a heat exchanger arranged for heat exchange between the cracked gas product from the primary catalytic conversion and the feed gas stream circulating within the secondary reactor 3. Heat from the cracked gas product is transferred to the secondary reactor. For example, the heat exchanger between the cracked gas and the secondary reactor 3 can be a fluid / fluid heat exchanger. In this case, the heat exchanger includes a section configured for the circulation of the ammonia feed stream and another section configured for the circulation of the cracked gas product from the primary catalytic conversion, the two sections being separated by a thermally conductive layer arranged for heat exchange between the ammonia feed stream and the cracked gas product from the primary catalytic conversion. The heat exchanger can be, for example, a shell-and-tube heat exchanger. The heat exchanger includes a circulation tube bundle contained within a cracked gas conduit 23 and arranged for the circulation of the cracked gas product, and a shell forming a conduit for the circulation of the ammonia feed stream, through which the circulation tube bundle extends.

[0118] The device includes a combustion chamber 2, which includes a combustion zone 12 in which a fuel gas stream is burned into combustion reaction flue gas. A fuel gas inlet 10 is configured as an inlet for fuel gas in the combustion chamber 2.

[0119] The device includes a pipe 24 for partially converted ammonia stream, which is arranged to discharge the partially converted ammonia stream from the secondary reactor and feed the discharged partially converted ammonia stream to the main reactor.

[0120] Secondary reactor 3 includes a feed distribution manifold and a partially converted ammonia stream collection manifold.

[0121] The main reactor 2 includes a catalyst layer configured to promote the catalytic conversion of the partially converted ammonia stream at a temperature of 350°C to 650°C, preferably about 550°C.

[0122] Secondary reactor 3 is packed with a secondary catalyst, which contains nickel as a catalytically active material, particularly as a catalytically active material on a support such as alumina (Al2O3). The secondary catalyst contains more than 20% by weight to more than 45% by weight of nickel, preferably more than 35% by weight, and / or noble metals, such as ruthenium, preferably more than 1.5% by weight of ruthenium, as a catalytically active material, particularly as a catalytically active material on a support.

[0123] Figure 2 This is a schematic diagram of the main reactor according to the first embodiment.

[0124] In this embodiment, reactor 209 includes an outer casing 204, which is pressurized. The outer casing 204 includes a reaction chamber A, in which the catalytic conversion of the ammonia feedstock stream is achieved; the catalytic conversion is a cracking reaction.

[0125] Reaction chamber A contains an active solid catalyst layer 205, which serves as a dump bed of active catalyst. This catalyst is configured to promote the catalytic conversion of ammonia into a hydrogen-containing cracked gas product at a temperature of 600°C to 900°C, preferably 700°C to 800°C, and a pressure of approximately 25 barA. The catalyst layer is, for example, a nickel-containing catalyst. Partially converted ammonia stream is circulated within the active catalyst layer 205 where the cracking reaction occurs. This reaction is possible at high temperatures, and heat 207 and 206 is supplied to reaction chamber A.

[0126] The outer casing 204, more precisely, the reaction chamber A, includes a heat exchange tube 208, which is part of the cracked gas conduit 23 and is arranged within the reaction chamber A to exchange heat with the catalyst layer 205 and the partially converted ammonia stream. In this embodiment, the heat exchange tube 208 is a single heat exchange tube made of a thermally conductive material such as a metal alloy, for example, alloy 600. In another embodiment, not shown here, the heat exchanger includes at least two tubes made of the aforementioned thermally conductive material. The reactor 209 is configured such that after the partially converted ammonia stream enters the reaction chamber A through inlet 201, the partially converted ammonia stream flows through the catalyst layer 205 for cracking at least a portion of the feed stream into the cracked gas product in the catalyst layer 205, and then the cracked gas product flows through the heat exchange tube 208, which is arranged inside the reaction chamber A.

[0127] The catalyst layer 205 is configured to be partially heated by external heat 207 from an external heat source, such as external ignition or electric heating. The partially converted ammonia stream is thus converted into the hydrogen-containing cracking product. The partially converted ammonia stream is heated, and this heat is provided to the cracking reaction. The cracked gas is then further heated. As the hot cracked gas product flows through the cracked gas heat exchange tube 208, it internally transfers its heat 206 to the catalyst layer 205. Thus, the catalyst layer is heated by both the external heat source 207 and the internal heat source 206. This reduces the consumption of external heat 207. In a preferred embodiment, the cracked gas product flows through the heat exchange tube 208 in a countercurrent manner.

[0128] The shell and tube includes a cracked gas product outlet 203, which is arranged to release cracked gas products from the main reactor.

[0129] Figure 3 This is a schematic diagram of the main reactor according to the second embodiment.

[0130] As in Figure 2 In one embodiment, the outer shell tube includes a pipe inlet 210 for partially converted ammonia stream, the pipe inlet 210 being configured to allow the ammonia feedstock stream to enter the outer shell tube 204, more precisely, into the reaction chamber A'.

[0131] In this embodiment, reactor 214 includes an outer casing 211, which includes a reaction chamber A' configured to be heated. The reactor includes an active catalyst layer 212 disposed within the reaction chamber A'. The catalyst layer 212 is arranged to promote a pyrolysis reaction that cracks a partially converted ammonia stream into the cracked gas product. The partially converted ammonia stream circulates within the catalyst layer 212, which promotes the pyrolysis reaction at a temperature of 600°C to 900°C and a pressure of 25 barA. Here, the catalyst layer contains nickel as the catalytically active material.

[0132] Reactor 214 includes two heat exchange tubes 213, which are part of the pyrolysis gas conduit 23 and are arranged for heat exchange between the pyrolysis gas product and the pyrolysis reaction in reaction chamber A'. Here, the heat exchange tubes 213 have a coiled helical shape, and these coiled helical structures are intertwined.

[0133] like Figure 2As shown, the catalyst layer 212 is configured to be partially heated by external heat 214 from an external heat source. The external heat source is, for example, external ignition or electric heating. The partially converted ammonia stream is thus converted into the hydrogen-containing cracked gas product. The partially converted ammonia stream is heated, and this heat is provided to the cracking reaction. The cracked gas is then further heated. As the hot cracked gas product flows through the cracked gas product circulation pipe of the heat exchanger 213, it internally transfers its heat 215 to the catalyst layer 212. Therefore, the catalyst layer is heated by both the external heat source 214 and the internal heat source 215. This reduces the consumption of external heat 215. In a preferred embodiment, the cracked gas product flows through the heat exchanger 213 in a countercurrent manner.

Claims

1. A method for producing hydrogen-containing cracked gas products from an endothermic cracking reaction of an ammonia feedstock, the method comprising the following steps: -Provide ammonia feedstock; - The main reactor is heated during the heating step; - In the heated main reactor, the partially converted ammonia stream is converted into the cracked gas product through a main endothermic catalytic conversion. - In the heat recovery step, heat is recovered from the pyrolysis gas product flowing in the pyrolysis gas pipeline (23); - In the heat redirection step, the heat recovered in the heat recovery step is redirected to at least one secondary reactor, the secondary reactor including a gas reaction section in which the secondary endothermic catalytic conversion of the ammonia feedstock to the partially converted ammonia stream is carried out. - In the heat transfer step, the redirected heat is transferred to the secondary endothermic catalytic conversion via a thermally conductive layer that at least partially defines the gas reaction section. The method includes: - A heat exchange step is performed by exchanging heat between the cracked gas product and the primary endothermic catalytic conversion, the heat exchange step comprising the following steps: - The cracked gas product is discharged in the cracked gas pipeline (23), which is arranged for heat exchange between the discharged cracked gas product and the main endothermic catalytic conversion; -Recover heat from the discharged cracked gas products; - The recovered heat is directed to the main endothermic catalytic conversion.

2. The method according to claim 1, wherein, The secondary catalytic conversion is located upstream of the main catalytic conversion in the direction of ammonia feedstock flow. The ammonia feedstock is converted into the partially converted ammonia stream through the secondary endothermic catalytic conversion, and the partially converted ammonia stream is converted into the cracked gas product through the main endothermic catalytic conversion.

3. The method according to any one of the preceding claims, comprising a preheating step of preheating the partially converted ammonia stream upstream of the main catalytic conversion.

4. An apparatus (1) for producing hydrogen-containing cracked gas products through an endothermic cracking reaction of an ammonia feedstock, the apparatus comprising: - At least one main reactor (2) is arranged to produce the cracked gas product by main endothermic catalytic conversion of a partially converted ammonia stream; - Arranged to discharge the pyrolysis gas product from the main reactor (2) via a pyrolysis gas pipeline (23); - A secondary reactor (3) comprising a gas reaction section (21) including a secondary catalyst configured to facilitate secondary catalytic conversion of the ammonia feedstock to the partially converted ammonia stream, the gas reaction section (21) being at least partially defined by a heat-conducting layer (22) arranged to recover some heat from the cracked gas product in the cracked gas conduit (23) and provide the recovered heat to the secondary catalyst. The main reactor includes: - Outer casing tube (211), which includes reaction chambers (A, A') configured to be heated; -A catalyst layer (205, 212) arranged in the reaction chamber for carrying out the main endothermic catalytic conversion; - An inlet for the ammonia feedstock stream for partial conversion is arranged in the reaction chambers (A, A'), and the inlet for the ammonia feedstock stream is fluidly connected to the catalyst layers (205, 212). For the equipment, the pyrolysis gas conduit (23) is arranged to exchange heat with the reaction chamber (A, A').

5. The device (1) according to claim 4, wherein, The secondary reactor (3) is arranged upstream of the main reactor (2) in the direction of ammonia feed flow.

6. The device (1) according to any one of claims 4 and 5, wherein, The equipment includes a partially converted ammonia conduit (24a, 24b) arranged to discharge the partially converted ammonia stream from the secondary reactor (3) and to feed the discharged partially converted ammonia stream into the main reactor.

7. The device (1) according to any one of claims 4 to 6, wherein, A portion of the pyrolysis gas conduit (23) extends inside the reaction chamber (A, A').

8. The apparatus (1) according to the preceding claim, configured to allow the ammonia stream of the partial conversion to flow through the catalyst layer (205, 212) in a countercurrent manner to the flow of the cracked gas product through the portion of the cracked gas conduit (23) extending inside the reaction chamber (A, A').

9. The device (1) according to any one of claims 4 to 8, wherein, The pyrolysis gas pipeline (23) includes a heat exchange section arranged in a heat exchange relationship with the reaction chamber (A, A').

10. The device (1) according to the preceding claim, wherein, The heat exchange section includes at least one heat exchange tube (208, 213) arranged for the circulation of the pyrolysis gas product and the heat exchange between the pyrolysis gas product and the reaction chamber (A, A').

11. The device (1) according to the preceding claim, wherein, The at least one heat exchange tube (208, 213) has a coiled spiral shape.

12. The device (1) according to claim 10 or 11, wherein, The heat exchange section includes at least two heat exchange tubes (213), each of which has a coiled spiral shape and the at least two heat exchange tubes (213) are staggered.

13. The device (1) according to any one of claims 4 to 12, wherein, The pyrolysis gas pipeline (23) includes a pyrolysis gas circulation section arranged in a heat exchange relationship with the gas reaction section.

14. The device (1) according to the preceding claim, wherein, The gas reaction section (21) includes a circulation tube bundle filled with the secondary catalyst, and the cracked gas circulation section includes a cracked gas circulation shell through which the circulation tube bundle extends.

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