Process for producing liquefied hydrogen from ammonia

Abstract

To provide a process and installation for producing and liquefying hydrogen from an ammonia feedstock stream.SOLUTION: A process 100 comprises the steps of: providing an ammonia feedstock stream 101; producing a hydrogen gas product 113 by a gas conversion 108, in which at least part of the ammonia feedstock stream is gas-converted and / or at least part of the ammonia feedstock stream is combusted to provide heat to the process, in particular to the gas conversion; liquefying 117 the hydrogen gas product at least by the following steps, precooling 105 the hydrogen gas product at a temperature between 70 kelvin and 100 kelvin, preferably around 80 kelvin, to obtain a precooled hydrogen gas product 106, and cooling the precooled hydrogen gas product at a temperature between 10 kelvin and 50 kelvin, preferably around 20 kelvin, and liquefying the hydrogen gas product to obtain liquid hydrogen; and cooling the hydrogen gas product by heat exchange with at least part of the ammonia feedstock stream 104 upstream the cooling of the precooled hydrogen gas product.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] [1] The field of the invention is that of processes for producing and liquefying hydrogen. The invention also relates to installations for producing and liquefying hydrogen. [Background technology]

[0002] [2] Ammonia is being investigated as a hydrogen carrier molecule or CO2-free fuel, advantageous for transporting large quantities over long distances. For example, it is well known to produce hydrogen by ammonia decomposition. The hydrogen needs to be further liquefied, for example, for its transportation. Therefore, it is necessary to have a hydrogen liquefaction unit downstream of the process that converts ammonia into hydrogen gas product. Summary of the Invention

[0003] [3] Hydrogen production and liquefaction is expensive and requires large amounts of energy. The present invention proposes a method to produce and liquefy hydrogen by utilizing the cryogenic energy available in the ammonia feed stream to a hydrogen liquefaction unit, thereby reducing the cost of producing and liquefying hydrogen and improving the efficiency of liquefied hydrogen production.

[0004] [4] To this end, the present invention proposes a process for producing and liquefying hydrogen, said process comprising the following steps: providing an ammonia feed stream; - Producing a hydrogen gas product by gas conversion; wherein at least a portion of said ammonia feed stream is converted by said gas conversion and / or at least a portion of said ammonia feed stream is combusted to provide heat to a process, in particular to said gas conversion, liquefying the hydrogen gas product by at least the following steps: a. pre-cooling said hydrogen gas product under conditions to pre-cool said hydrogen gas product at a temperature between 70 and 100 Kelvin, preferably about 80 Kelvin, thereby obtaining a pre-cooled hydrogen product; b. cooling the pre-cooled hydrogen gas product under conditions effective to cool it to a temperature between 10 and 50 Kelvin, preferably about 20 Kelvin, thereby liquefying the hydrogen gas product to obtain liquid hydrogen. - cooling the hydrogen gas product by heat exchange with at least a portion of the ammonia feed stream upstream of step b.

[0005] [5] An ammonia feed stream in this disclosure is understood as a feed stream that is arranged to be converted by gas conversion and / or combusted in a combustion chamber to heat the gas reaction.

[0006] [6] In one embodiment, the gas conversion produces a waste gas product from which the hydrogen gas product is derived.

[0007] [7] In one embodiment, at least a portion of the ammonia feed stream is converted by gas conversion comprising an endothermic reaction, and in particular by said endothermic reaction to said tail gas product comprising hydrogen.

[0008] [8] In one embodiment, at least a portion of the ammonia feed stream is converted by gas conversion comprising an ammonia decomposition reaction, and in particular by the ammonia decomposition reaction to the exhaust gas products comprising hydrogen and nitrogen, which may also comprise unconverted ammonia.

[0009] [9] In one embodiment, at least a portion of the ammonia feed stream is combusted to provide heat for the gas conversion, which comprises an endothermic reaction. In another example, heat may be provided to another step in the process, such as a distillation step.

[0010]

[10] In one embodiment, the gas conversion comprises conversion of a hydrocarbon feedstock to the tail gas product, which is synthesis gas. The gas conversion may alternatively comprise an ammonia decomposition reaction.

[0011]

[11] In one embodiment, the ammonia feed stream is vaporized and at least a portion of the vaporized ammonia feed stream is converted by said gas conversion, and / or at least a portion of the vaporized ammonia feed stream is combusted to provide heat to the process, in particular to said gas conversion.

[0012]

[12] According to one aspect of the invention, the process comprises a step of treating the exhaust gas product, thereby recovering said hydrogen gas product. The treating step can be, for example, a purification step using methods such as pressure swing adsorption (acronym PSA), cryogenic separation, membrane and / or temperature swing adsorption (acronym TSA) to obtain the hydrogen gas product. The temperature of the hydrogen gas product after this step can be between 40°C and 50°C.

[0013]

[13] In one embodiment, the step of pre-cooling the hydrogen gas product comprises introducing the hydrogen gas product into a pre-cooling system including a pre-cooling gas cycle through which pre-cooling gas circulates under conditions effective to pre-cool the hydrogen gas product to a temperature of between 70 and 100 Kelvin, preferably about 80 Kelvin, to obtain a pre-cooled hydrogen product.

[0014]

[14] In one embodiment, the pre-cooled gas and the hydrogen gas product exchange heat during the pre-cooling step.

[0015]

[15] In one embodiment, the step of cooling the pre-cooled hydrogen gas product comprises introducing the pre-cooled hydrogen gas product into a refrigeration system using a refrigerated gas cycle in which a refrigerated gas is circulated under conditions effective to cool the pre-cooled hydrogen gas product to a temperature of between 10 and 50 Kelvin, preferably about 20 Kelvin, thus liquefying the pre-cooled hydrogen gas product to obtain liquid hydrogen.

[0016]

[16] In one embodiment, the cooling gas and the hydrogen gas product exchange heat during the step of liquefying the hydrogen gas product, particularly during cooling of the pre-cooled hydrogen gas product of the liquefaction step.

[0017]

[17] In one embodiment, the step of liquefying the hydrogen gas product comprises cooling the hydrogen gas product by heat exchange with at least a portion of the ammonia feed stream.

[0018]

[18] According to one embodiment, the hydrogen gas product is cooled with only a portion of the ammonia feed stream.

[0019]

[19] According to one aspect of the invention, the supplied ammonia feed stream has a temperature below 0°C, but preferably below -25°C.

[0020]

[20] According to one aspect of the invention, the hydrogen gas product is cooled with at least a portion of the ammonia feedstock upstream of a pre-cooling step.

[0021]

[21] In this embodiment, the hydrogen gas product temperature may be reduced by 30°C to 70°C, preferably 40°C to 80°C, after heat exchange between the hydrogen gas product and all or a portion of the ammonia feed stream.

[0022]

[22] In one embodiment, the ammonia in the ammonia feed stream used to cool the hydrogen gas product is liquid ammonia, and said ammonia remains liquid after heat exchange with said hydrogen gas product.

[0023]

[23] In one embodiment, the ammonia used to cool the hydrogen gas product is sent to gas conversion after heat exchange with the hydrogen gas product, particularly after being vaporized by other means.

[0024]

[24] In one embodiment, the hydrogen gas product is cooled with at least a portion of the ammonia feedstock upstream of the pre-cooling step and downstream of the treatment step in the direction of flow of the hydrogen gas product.

[0025]

[25] According to another embodiment, the hydrogen gas product is cooled with the ammonia feed stream as part of the pre-cooling step, in particular by heat exchange between the pre-cooling gas cycle and the ammonia feed stream.

[0026]

[26] In this embodiment in which the hydrogen gas product is cooled with the ammonia feed stream by heat exchange between the pre-cooled gas cycle and the ammonia feed stream, the heat exchange between the ammonia feed stream and the hydrogen gas product is carried out by a first heat exchange between the ammonia feed stream and the pre-cooled gas in a first heat exchanger to obtain cooled pre-cooled gas, and a second heat exchange between the cooled pre-cooled gas and the hydrogen gas product in a second heat exchanger.

[0027]

[27] In other words, the process comprises a first cryogenic transfer of an ammonia feed stream to a pre-cooled gas stream and a second cryogenic transfer of the cooled pre-cooled gas stream to a hydrogen gas product.

[0028]

[28] In this embodiment, the pre-cooling gas cycle temperature may be reduced by 15°C to 45°C, preferably 25°C to 50°C, after heat exchange between the gas cycle and the ammonia feed stream.

[0029]

[29] According to one aspect of the invention, the hydrogen product gas is cooled by an ammonia feed stream downstream of the processing of the hydrogen gas product and upstream of the liquefaction of said hydrogen gas product.

[0030]

[30] According to one aspect of the invention, the pre-cooling gas circulating through the pre-cooling gas cycle is compressed in the pre-cooling cycle by at least one compressor.

[0031]

[31] According to one aspect of the invention, the compressed pre-cooled gas is cooled by heat exchange with an ammonia feed stream, and the cooled and compressed pre-cooled gas exchanges heat with a hydrogen gas product. In particular, the cooled and compressed pre-cooled gas is expanded, and the expanded pre-cooled gas recovers heat from the hydrogen gas product, thereby pre-cooling said hydrogen gas product.

[0032]

[32] According to one aspect of the invention, a pre-cooled gas is at least partially cooled by heat exchange with an ammonia feed stream, the cooled pre-cooled gas is compressed by a compressor, and the cooled and compressed pre-cooled gas is heat exchanged with a hydrogen gas product.

[0033]

[33] In particular, the ammonia feed stream exchanges heat with the precooled gas downstream of the compression of the precooled gas in the flow direction of the precooled gas between the expansion of the precooled gas and said compression.

[0034]

[34] According to another embodiment, the hydrogen gas product is cooled with the ammonia feed stream upstream of and as part of the pre-cooling step, in particular by heat exchange between the pre-cooling gas cycle and the ammonia feed stream. In other words, the hydrogen gas product is cooled with the ammonia feed stream both upstream of and as part of the pre-cooling step.

[0035]

[35] The present invention also proposes an installation for producing and liquefying hydrogen, said installation comprising: an inlet for an ammonia feed stream; a gas conversion unit arranged to produce a hydrogen gas product; - optionally a combustion chamber arranged for combustion of an ammonia feed stream, in particular arranged in heat exchange relationship with said gas conversion unit; an ammonia feed stream circulation duct fluidly connected to a gas conversion unit for producing said hydrogen gas product by gas conversion of an ammonia feed stream and / or fluidly connected to said combustion chamber; a liquefaction unit arranged to liquefy the hydrogen gas product; at least one heat exchanger positioned for the transfer of heat from said hydrogen gas product to said ammonia feed stream.

[0036]

[36] In one embodiment, the gas conversion unit is configured to convert an ammonia feed stream by gas conversion into a tail gas product comprising hydrogen.

[0037]

[37] In one embodiment, the gas conversion unit comprises a cracker configured to crack the ammonia feed stream into said exhaust gas comprising hydrogen and nitrogen.

[0038]

[38] In one embodiment, the gas conversion unit comprises a reactor configured to convert a hydrocarbon feedstock into said exhaust gas product, wherein said exhaust gas product is a synthesis gas product. For example, the reactor is a reformer.

[0039]

[39] In one embodiment, the facility comprises an ammonia vaporizer positioned to vaporize an ammonia feed stream upstream of the gas conversion unit and / or combustion chamber.

[0040]

[40] In one embodiment, the facility includes a purification unit configured to purify the exhaust gas product and thereby recover the hydrogen gas product. For example, the purification unit includes a pressure swing adsorption purification unit, a cryogenic separation purification unit, a membrane, and / or a temperature swing adsorption (acronym TSA) purification unit.

[0041]

[41] In one embodiment, the liquefaction unit comprises a pre-cooling system arranged to pre-cool the hydrogen gas product at a temperature between 70 and 100 Kelvin, preferably about 80 Kelvin, to obtain a pre-cooled hydrogen gas product.

[0042]

[42] In one embodiment, the pre-cooling system comprises a pre-cooling gas cycle for circulating a pre-cooling gas under conditions effective to pre-cool the hydrogen gas product to a temperature of between 70 and 100 Kelvin, preferably about 80 Kelvin, to obtain a pre-cooled hydrogen product. The pre-cooling gas may be, for example, nitrogen.

[0043]

[43] In one embodiment, the liquefaction unit comprises a refrigeration system arranged to cool the pre-cooled hydrogen gas product under conditions effective to cool said pre-cooled hydrogen gas product to a temperature of between 10 and 50 Kelvin, preferably to a temperature of about 20 Kelvin, thus liquefying the hydrogen gas product to obtain liquid hydrogen.

[0044]

[44] In one embodiment, the refrigeration system comprises a refrigerated gas cycle for circulating refrigerated gas under conditions effective to cool the pre-cooled hydrogen gas product to a temperature between 10 and 50 Kelvin, preferably about 20 Kelvin, and liquefy the pre-cooled hydrogen gas product to obtain liquid hydrogen.

[0045]

[45] In one embodiment, the facility comprises a waste heat boiler arranged to cool the exhaust gas product, said waste heat boiler being arranged downstream of the gas conversion unit and upstream of the purification unit.

[0046]

[46] In one embodiment, the installation comprises a scrubbing column arranged to separate unconverted ammonia from the exhaust gas product by absorption, in particular by scrubbing the exhaust gas product.

[0047]

[47] In one embodiment, the installation comprises a cooling water heat exchanger arranged to cool the scrubbed exhaust gas product, said cooling water heat exchanger being arranged between the scrubber column and the purification unit.

[0048]

[48] ​​In one embodiment, at least one heat exchanger arranged for the transfer of heat from the hydrogen gas product to the ammonia feed stream is arranged upstream of the cooling system in the direction of flow of the hydrogen gas product, for example a shell-and-tube heat exchanger.

[0049]

[49] In one embodiment, at least one heat exchanger is positioned upstream of the pre-cooling system in the flow direction of the hydrogen gas product.

[0050]

[50] In one embodiment, at least one heat exchanger is included in the pre-cooling system.

[0051]

[51] In one embodiment, the at least one heat exchanger is arranged downstream of the purification unit and upstream of the pre-cooling system in the flow direction of the hydrogen gas product. In other words, the at least one heat exchanger is arranged to cool the hydrogen gas product downstream of purification by the purification unit and upstream of pre-cooling of said hydrogen gas product by the pre-cooling system.

[0052]

[52] In one embodiment, the at least one heat exchanger comprises a first heat exchanger arranged to exchange heat between the precooled gas circulating in the precooled gas cycle and the ammonia feed stream, thereby obtaining a cooled precooled gas, and a second heat exchanger arranged to exchange heat between the cooled precooled gas and the hydrogen gas product. In this embodiment, the first heat exchanger and / or the second heat exchanger may be, for example, a shell-and-tube heat exchanger or a brazed aluminum heat exchanger (BAHX) heat exchanger.

[0053]

[53] In one embodiment, the pre-cooling system comprises at least one compressor arranged to compress the pre-cooled gas in the pre-cooled gas cycle.

[0054]

[54] In one embodiment, the pre-cooling system comprises at least one expansion device arranged to expand the pre-cooled gas, in particular the compressed pre-cooled gas.

[0055]

[55] In one embodiment, the first heat exchanger is arranged downstream of the compressor and upstream of the second heat exchanger in the pre-cooling gas flow direction. In other words, the first heat exchanger is arranged to cool the compressed pre-cooling gas with the ammonia feed stream, and the second heat exchanger is arranged to cool the hydrogen gas product with the cooled and compressed pre-cooling gas. In particular, the first heat exchanger is arranged downstream of the compressor of the pre-cooling system and upstream of the expansion device in the pre-cooling gas flow direction.

[0056]

[56] In one embodiment, the first heat exchanger is arranged downstream of the second heat exchanger, which is arranged to exchange heat between the cooled pre-cooled gas and the hydrogen gas product and is arranged upstream of the compressor in the pre-cooled gas flow direction. In other words, the first heat exchanger is arranged to cool the pre-cooled gas with the ammonia feed stream upstream of the compressor in the pre-cooled gas flow direction, and the second heat exchanger is arranged to cool the hydrogen gas product with the cooled and compressed pre-cooled gas. In particular, the first heat exchanger is arranged downstream of the expansion device and upstream of the compressor of the pre-cooled system in the pre-cooled gas flow direction.

[0057]

[57] According to another embodiment, at least one heat exchanger comprises: In the pre-cooling system, a first heat exchanger positioned to exchange heat between the pre-cooled gas and the ammonia feed stream; a second heat exchanger positioned to exchange heat between the cooled pre-cooled gas and the hydrogen gas product; a third heat exchanger arranged upstream of the pre-cooling system in a flow direction of the hydrogen gas product, said third heat exchanger being arranged to exchange heat between the hydrogen gas product and the ammonia feed stream upstream of the pre-cooling system in a flow direction of the hydrogen gas product.

[0058]

[58] Further features, details and advantages of the present invention will become more clearly apparent from reading the description given below by way of illustration, with reference to the drawings. [Brief explanation of the drawings]

[0059] [Figure 1]

[59] Figure 1 is a schematic diagram of the process of the present invention according to a first embodiment. [Figure 2]

[60] Figure 2 is a schematic diagram of the process of the present invention according to a second embodiment. [Figure 3]

[61] Figure 3 is a schematic diagram of the process of the present invention according to a third embodiment. [Figure 4]

[62] Figure 4 is a schematic diagram of the process of the present invention according to a fourth embodiment. [Figure 5]

[63] Figure 5 is a schematic diagram of the process of the present invention according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0060]

[64] Figures 1-5 depict different embodiments of the process for producing and liquefying hydrogen according to the present invention.

[0061]

[65] The processes 100, 200, 300, 400, and 500 comprise the following steps: providing an ammonia feed stream 101, 201, 301, 401, 501; - Producing a hydrogen gas product 113, 213, 313, 413, 513 by gas conversion 108, 208, 308, 408, 508; wherein at least a portion of the ammonia feed stream is converted by the gas conversion 108, 208, 308, 408, 508, and / or at least a portion of the ammonia feed stream is combusted, in particular to provide heat for the gas conversion 108, 208, 308, 408, 508; liquefying the hydrogen gas product 117, 217, 317, 417, 517 by at least the following steps: pre-cooling (105, 205, 305, 405, 505) the hydrogen gas product under conditions for pre-cooling the hydrogen gas product at a temperature between −70 Kelvin and 100 Kelvin, preferably about 80 Kelvin, thereby obtaining a pre-cooled hydrogen product; - cooling (106, 206, 306, 406, 506) the pre-cooled hydrogen gas product under conditions effective to cool it to a temperature between 10 and 50 Kelvin, preferably about 20 Kelvin, thereby liquefying the hydrogen gas product to obtain liquid hydrogen; - cooling the pre-cooled hydrogen gas product 106, 206, 306, 406, 506 upstream of the cooling of the hydrogen gas product by heat exchange with at least a portion of the ammonia feed stream 104, 204, 304, 404a, 404b, 504a, 504b.

[0062]

[66] "A portion of the ammonia" means that only a portion of the ammonia feed stream may be used to cool the hydrogen gas product, while at least another portion is arranged to be combusted, for example, to produce hydrogen gas product in the gas conversion and / or to provide heat for the gas reaction.

[0063]

[67] The step 101, 201, 301, 401, 501 of providing an ammonia feed stream here comprises pumping said ammonia feed stream.

[0064]

[68] After providing the ammonia feed stream, the ammonia feed stream may be vaporized 107, 207, 307, 407, 507, and at least a portion of the vaporized ammonia feed stream may be converted by the gas conversion 108, 208, 308, 408, 508, and / or at least a portion of the vaporized ammonia feed stream may be combusted to provide heat, among other things, to the gas conversion 108, 208, 308, 408, 508. In another example, the heat may be provided to another step in the process, such as a distillation step.

[0065]

[69] The gas conversion 108, 208, 308, 408, 508 generates an exhaust gas product from which a hydrogen gas product is derived. The exhaust gas product comprises hydrogen, nitrogen, and unconverted ammonia. The ammonia feed stream is converted by the gas conversion 108, 208, 308, 408, 508 comprising an endothermic reaction, specifically, converted to the exhaust gas product comprising hydrogen by the endothermic reaction. For example, the ammonia feed stream is converted by the gas conversion 108, 208, 308, 408, 508 comprising an ammonia decomposition reaction, specifically, converted to the exhaust gas product comprising hydrogen and nitrogen by the ammonia decomposition reaction. The exhaust gas product may also comprise unconverted ammonia. When the conversion gas comprises an ammonia decomposition reaction, the ammonia feed stream may also be combusted to provide heat for the ammonia decomposition reaction. In other words, the ammonia feed stream may be included in the fuel gas to heat the ammonia decomposition reaction. In another embodiment, a different fuel gas, such as a fuel gas that does not comprise an ammonia feed stream, can be used to heat the ammonia cracking reaction.

[0066] In another example not shown, the gas conversion 108, 208, 308, 408, 508 comprises conversion of a hydrocarbon feedstock to the exhaust gas product, which is synthesis gas. The gas conversion 108, 208, 308, 408, 508 may comprise, for example, a steam methane reforming reaction. At least a portion of the ammonia feed stream may be combusted to provide heat for the gas conversion 108, 208, 308, 408, 508, which may comprise an endothermic reaction.

[0067]

[71] The exhaust gas products are then cooled in waste heat boilers 109, 209, 309, 409, 509.

[0068]

[72] Here, the process comprises a step of separating unconverted ammonia from the exhaust gas product by absorption 110, 210, 310, 410, 510, in particular by washing the exhaust gas product with, for example, water. The washed exhaust gas product may then be cooled in a cooling water heat exchanger 111, 211, 311, 411, 511. For example, the temperature of the released hydrogen gas product is reduced by 10°C to 20°C during this step. For example, the released hydrogen gas product may have a temperature between 45°C and 55°C before heat exchange in the water heat exchanger, and the released hydrogen gas product may have a temperature between 35°C and 45°C after heat exchange in the water heat exchanger.

[0069]

[73] According to one aspect of the invention, the treatment step is achieved after cooling the scrubbed exhaust gas product in a water heat exchanger.

[0070] 1 to 5 also comprise a step of treating (103, 203, 303, 403, 503) the exhaust gas product, thereby recovering said hydrogen gas product. The treating step 103, 203, 303, 403, 503 may be a purification step using methods such as pressure swing adsorption (acronym PSA), cryogenic separation, membrane, temperature swing adsorption (acronym TSA) to obtain the hydrogen gas product. The temperature of the hydrogen gas product after this step may be between 40°C and 50°C.

[0071]

[75] To liquefy the hydrogen gas product 117, 217, 317, 417, 517, the hydrogen gas product is pre-cooled 105, 205, 305, 405, 505 by introducing the hydrogen gas product into a pre-cooling system under conditions effective to pre-cool the hydrogen gas product to a temperature between 70 and 100 Kelvin, preferably about 80 Kelvin, using a pre-cooling gas cycle through which a pre-cooled gas is circulated, to obtain a pre-cooled hydrogen product. The pre-cooled gas and the hydrogen gas product exchange heat during the pre-cooling step 105, 205, 305, 405, 505.

[0072]

[76] The pre-cooled hydrogen gas product is then cooled 106, 206, 306, 406, 506 by introducing the pre-cooled hydrogen gas product into a cooling system, particularly using a cooling gas cycle in which a cooling gas is circulated, under conditions effective to cool the pre-cooled hydrogen gas product to a temperature of between 10 and 50 Kelvin, preferably about 20 Kelvin, thus liquefying the pre-cooled hydrogen gas product to obtain liquid hydrogen.

[0073]

[77] The process comprises at least one step of cooling the hydrogen gas product with an ammonia feed stream 104, 204, 304, 404, 504. A portion of the ammonia feed stream is directed 102, 202, 302, 402, 502 to a step of cooling the hydrogen gas product with the ammonia feed stream. The hydrogen gas product is cooled 104, 204, 304, 404, 504 by heat exchange with the ammonia feed stream. The ammonia in the ammonia feed stream used to cool the hydrogen gas product is liquid ammonia, and the ammonia remains liquid after heat exchange with the hydrogen gas product. After heat exchange between the ammonia feed stream and the hydrogen gas product, the ammonia used to cool the hydrogen gas product is directed to gas conversion 112, 212, 312, 412, 512.

[0074]

[78] Figure 1 discloses a process 100 of the present invention according to a first embodiment. In this embodiment, the hydrogen gas product is cooled 104 with the ammonia feedstock upstream of a pre-cooling step 105 by heat exchange between the hydrogen gas product and the ammonia feed stream in a heat exchanger, such as a shell-and-tube heat exchanger. More precisely, the hydrogen gas product is cooled 104 with the ammonia feedstock upstream of the pre-cooling step 105 and downstream of the treatment step 103 in the flow direction of the hydrogen gas product. In this embodiment, the hydrogen gas product temperature can be reduced by 30°C to 70°C, preferably 40°C to 70°C, and preferably 50°C to 70°C after heat exchange between said hydrogen gas product and the ammonia feed stream. For example, the hydrogen gas product temperature before heat exchange with the ammonia feed stream may be 40°C to 50°C, and the hydrogen gas product temperature after heat exchange with the ammonia feed stream may be -15°C to -25°C.

[0075] 2 and 3 disclose two embodiments in which the hydrogen gas product is cooled 204, 304 with an ammonia feed stream as part of the pre-cooling step 205, 305, in particular by heat exchange between the pre-cooled gas cycle and the ammonia feed stream. The pre-cooling system comprises a first heat exchanger arranged to transfer heat of the ammonia feed stream to the pre-cooled gas 204, 304, and a second heat exchanger arranged to transfer heat of the cooled pre-cooled gas stream to the hydrogen gas product 215, 315. In this embodiment, the gas cycle temperature can be reduced by 15°C to 45°C, preferably 25°C to 45°C, preferably 35°C to 45°C after heat exchange between said gas cycle and the ammonia feed stream. For example, the gas cycle temperature before heat exchange with the ammonia feed stream may be 25°C to 35°C, and the gas cycle temperature after heat exchange with the ammonia feed stream may be -10°C to -20°C.

[0076]

[80] The pre-cooled gas circulating in the pre-cooled gas cycle is compressed in the pre-cooled cycle by at least one compressor (114, 214, 314, 414, 514). The hydrogen gas product may be cooled with the ammonia feed stream simultaneously with pre-cooling the hydrogen gas product.

[0077]

[81] In the embodiment of Figure 2, the compressed 214 pre-cooled gas is first cooled 204 by heat exchange with an ammonia feed stream, and the cooled 204 and compressed 214 pre-cooled gas exchanges heat with a hydrogen gas product 215. In particular, the compressed pre-cooled gas is cooled, the cooled pre-cooled gas is expanded (not shown here), and the expanded pre-cooled gas recovers heat from the hydrogen gas product, thereby pre-cooling said hydrogen gas product. In this case, the ammonia feed stream exchanges heat with the pre-cooled gas downstream of the compression of the pre-cooled gas.

[0078] 3, the pre-cooled gas is cooled 304 by heat exchange with an ammonia feed stream, the cooled pre-cooled gas is compressed 314 by a compressor, and the cooled 304 and compressed 314 pre-cooled gas exchanges heat with hydrogen gas product 315. In particular, the ammonia feed stream exchanges heat with the pre-cooled gas downstream of the compression of the pre-cooled gas in the flow direction of the pre-cooled gas, in particular between the expansion of the pre-cooled gas and said compression. In this embodiment, the pre-cooled gas may be cooled by other means.

[0079]

[83] Figure 4 depicts a process incorporating features of the first and second embodiments, and Figure 5 depicts a process incorporating features of the first and third embodiments. Thus, the hydrogen gas product is cooled with the ammonia feed stream upstream of and as part of the pre-cooling step, in particular by heat exchange between the pre-cooling gas cycle and the ammonia feed stream. In other words, the hydrogen gas product is cooled with the ammonia feed stream both upstream of and as part of the pre-cooling step.

Claims

1. A process (100, 200, 300, 400, 500) for producing and liquefying hydrogen, said process comprising: - providing an ammonia feed stream (101, 201, 301, 401, 501); - Producing a hydrogen gas product (113, 213, 313, 413, 513) by gas conversion (108, 208, 308, 408, 508); wherein at least a portion of said ammonia feed stream is converted by said gas conversion (108, 208, 308, 408, 508) and / or at least a portion of said ammonia feed stream is combusted to provide heat to said process, in particular to said gas conversion (108, 208, 308, 408, 508); - liquefying (117, 217, 317, 417, 517) said hydrogen gas product by at least the following steps: pre-cooling (105, 205, 305, 405, 505) said hydrogen gas product under conditions for pre-cooling said hydrogen gas product at a temperature between −70 Kelvin and 100 Kelvin, preferably about 80 Kelvin, thereby obtaining a pre-cooled hydrogen product; - cooling the pre-cooled hydrogen gas product (106, 206, 306, 406, 506) under conditions effective to cool said pre-cooled hydrogen gas product to a temperature of between 10 and 50 Kelvin, preferably about 20 Kelvin, thereby liquefying said hydrogen gas product to obtain liquid hydrogen; - cooling said pre-cooled hydrogen gas product (106, 206, 306, 406, 506) upstream of the cooling of said hydrogen gas product by heat exchange with at least a portion of an ammonia feed stream (104, 204, 304, 404a, 404b, 504a, 504b).

2. 10. The process of claim 1, wherein the gas conversion (108, 208, 308, 408, 508) produces an exhaust gas product from which the hydrogen gas product is derived.

3. 3. The process of claim 1 or 2, wherein at least a portion of the ammonia feed stream is combusted to provide heat for the gas conversion (108, 208, 308, 408, 508), which comprises an endothermic reaction.

4. 4. The process of any one of claims 1 to 3, wherein the ammonia feed stream is vaporized (107, 207, 307, 407, 507) and at least a portion of the vaporized ammonia feed stream is converted by the gas conversion (108, 208, 308, 408, 508) and / or at least a portion of the vaporized ammonia feed stream is combusted to provide heat to the process, in particular the gas conversion.

5. 5. The process of claim 2, or claim 3 or 4 when dependent on claim 2, wherein the process comprises treating (103, 203, 303, 403, 503) the exhaust gas product, thereby recovering the hydrogen gas product.

6. 6. The process of any one of claims 1 to 5, wherein the step of pre-cooling the hydrogen gas product (105, 205, 305, 405, 505) comprises introducing the hydrogen gas product into a pre-cooling system comprising a pre-cooling gas cycle through which pre-cooling gas circulates under conditions effective to pre-cool the hydrogen gas product to a temperature of between 70 and 100 Kelvin, preferably about 80 Kelvin, to obtain a pre-cooled hydrogen product.

7. 7. The process of any one of claims 1 to 6, wherein the ammonia feed stream supplied has a temperature below 0°C, preferably below -25°C.

8. 8. The process of any one of claims 1 to 7, wherein the hydrogen gas product is cooled with at least a portion of the ammonia feedstock (104, 404, 504a) upstream of a pre-cooling step (105, 205, 305, 405, 505).

9. 9. The process of any one of claims 1 to 8, wherein the hydrogen gas product is cooled with the ammonia feed stream (204, 304, 404B, 504B) as part of a pre-cooling step (105, 205, 305, 405, 505), in particular by heat exchange between a pre-cooling gas cycle and the ammonia feed stream.

10. 1. A facility for producing and liquefying hydrogen, said facility comprising: an inlet for an ammonia feed stream; a gas conversion unit configured to produce a hydrogen gas product; optionally a combustion chamber arranged for combustion of said ammonia feed stream, in particular arranged in heat exchange relationship with said gas conversion unit; an ammonia feed stream circulation duct fluidly connected to the gas conversion unit for producing the hydrogen gas product by gas conversion of the ammonia feed stream and / or fluidly connected to the combustion chamber; a liquefaction unit arranged to liquefy said hydrogen gas product; at least one heat exchanger arranged for transfer of heat from the hydrogen gas product to the ammonia feed stream, wherein the gas conversion unit is arranged to convert the ammonia feed stream by gas conversion to a tail gas product comprising hydrogen; The facility includes a purification unit configured to purify the exhaust gas product, thereby recovering the hydrogen gas product.

11. 11. The installation of claim 10, wherein the liquefaction unit comprises a pre-cooling system arranged to pre-cool the hydrogen gas product at a temperature between 70 and 100 Kelvin, preferably about 80 Kelvin, to obtain a pre-cooled hydrogen gas product.

12. 12. The installation according to claim 10 or 11, wherein the at least one heat exchanger is arranged upstream of a pre-cooling system in a flow direction of the hydrogen gas product.

13. 13. The installation according to claim 11 or 12, wherein the at least one heat exchanger is included in a pre-cooling system.

Images