Device for hydrogen production

Abstract

A hydrogen generation apparatus for generating hydrogen-rich gas from ammonia, comprising: a first chamber having an inner wall and an outer wall defining an internal volume, wherein the first chamber includes an ammonia decomposition catalyst disposed between the inner wall and the outer wall, the first chamber having one or more ammonia gas inlets and one or more untreated decomposition gas outlets, the one or more ammonia gas inlets and the one or more untreated decomposition gas outlets are arranged such that the ammonia flows through the first chamber from the one or more ammonia gas inlets to the one or more untreated decomposition gas outlets and into contact with the ammonia decomposition catalyst; and one or more heat sources for heating the ammonia decomposition catalyst, the first chamber having one or more fins, the one or more fins being disposed between the inner wall and the outer wall of the first chamber.

Description

[Background technology]

[0001] Hydrogen gas is a promising clean fuel that will play a key role as part of global efforts to mitigate climate change. Hydrogen gas can be easily combusted or used to generate electrical energy using specialized devices such as fuel cells. There are several ways to produce hydrogen, such as steam reforming of natural gas or electrolysis of water. However, one promising method for producing clean hydrogen is catalytic cracking (commonly called "catalytic cracking" or simply "cracking"), which decomposes ammonia gas into hydrogen and nitrogen according to the following reaction:

number

[0002] Apparatus for producing hydrogen by this method is commonly called an "ammonia cracker" and comprises a heating chamber containing a catalyst through which ammonia gas flows. Upon contact with the catalyst, the ammonia is decomposed, producing hydrogen and nitrogen gases. Such apparatuses are known in the art (see, for example, Patent Document 1).

[0003] The basic premise is to pass heated ammonia gas through an ammonia decomposition catalyst within the correct temperature range, catalytically converting ammonia into hydrogen and nitrogen. The output gas is typically a mixture of hydrogen, nitrogen, and residual undecomposed ammonia from the decomposition reaction, which is the equilibrium between ammonia and the decomposed gas. To obtain an output that does not contain nitrogen or ammonia, a further filtration step is required to purify the hydrogen (i.e., the use of a gas separator such as a palladium filter or a pressure swing adsorption device).

[0004] To optimize the reaction conditions within the reaction chamber of such equipment, the inflow gas flow rate, pressure, and residence time must be carefully controlled to maximize ammonia decomposition as efficiently as possible without compromising the equipment's lifespan. Furthermore, good heat transfer is necessary to minimize the reactor volume and maximize catalyst utilization.

[0005] The applicants have discovered a reaction chamber architecture that addresses the shortcomings of prior art apparatus in order to optimize the decomposition of ammonia into nitrogen and hydrogen. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2009 / 098452 [Patent Document 2] U.S. Patent Application Publication No. 2003 / 0232224 [Patent Document 3] U.S. Patent No. 4430304 [Patent Document 4] U.S. Patent No. 2578193 [Patent Document 5] U.S. Patent No. 6340382 [Patent Document 6] UK Patent Application Publication No. 969673 [Patent Document 7] UK Patent Application Publication No. 2508649 [Overview of the project]

[0007] In a first aspect, the present invention provides a hydrogen generation apparatus for generating hydrogen-rich gas from ammonia, the apparatus comprising a first chamber having an inner wall and an outer wall defining an internal volume, the first chamber containing an ammonia decomposition catalyst disposed between the inner wall and the outer wall, the first chamber having one or more ammonia gas inlets and one or more untreated decomposition gas outlets, the one or more ammonia gas inlets and the one or more untreated decomposition gas outlets are arranged such that the ammonia flows through the first chamber from the one or more ammonia gas inlets to the one or more untreated decomposition gas outlets and into contact with the ammonia decomposition catalyst, the first chamber having one or more fins, the one or more fins disposed between the inner wall and the outer wall of the first chamber, the first chamber having an internal surface area, the internal volume being between 10 ml and 100 liters, mm 3 mm 2 The ratio of the internal surface area of ​​the unit is between approximately 1:2 and 1:6.

[0008] In some embodiments, at least one of the one or more heat sources is located near the inner wall or near the outer wall.

[0009] In some embodiments, one or more heat sources comprise at least two heat sources, preferably at least one of which is located near the inner wall and at least one of which is located near the outer wall.

[0010] In some embodiments, at least one of the one or more fins is attached to and / or extends from the inner wall.

[0011] In some embodiments, at least one of the fins and the inner wall are integrally structured.

[0012] In some embodiments, at least one of the one or more fins is connected to the inner wall by a mechanical interference fit or mechanical fastener. In some embodiments, at least one of the one or more fins is attached to the inner wall by a joint. In further embodiments, one or more fins are made of a different material from the inner or outer wall of the first chamber. In further embodiments, the joint is welding or brazing.

[0013] In some embodiments, one or more fins comprise a plurality of fins. In further embodiments, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or more of the plurality of fins are attached to and / or extend from the inner wall. In another embodiment, the plurality of fins are attached to and / or extend from the inner wall. In further embodiments, the plurality of fins are arranged as one or more helices along the entire length of the first chamber.

[0014] In some embodiments, the fins are arranged in one or more rows, and each fin in each row is parallel to each other in the same row on a plane substantially perpendicular to the length of the first chamber.

[0015] In some embodiments, each fin of a plurality of fins has the same angle to one another.

[0016] In some embodiments, at least one of the multiple fins has a different angle from at least one other fin. In further embodiments, at least one of the multiple fins having a different angle from at least one other fin is in the same row as at least one other fin. In one embodiment, the multiple fins are arranged in at least two rows, and at least one of the multiple fins having a different angle from at least one other fin is in a different row from at least one other fin.

[0017] In some embodiments, the angle of each fin is selected from the group consisting of substantially perpendicular to the length of the first chamber, substantially parallel to the length of the chamber, and / or an angle between substantially perpendicular and substantially parallel to the length of the chamber.

[0018] In some embodiments, at least one of the one or more fins has a planar profile.

[0019] In some embodiments, at least one of the one or more fins has a profile that varies along its entire length. In further embodiments, at least one of the one or more fins comprises one or more openings and / or one or more protrusions and / or one or more recesses on the surface of at least one fin. In some embodiments, at least one of the one or more fins may be a hollow fin comprising a sub-chamber defined by one or more fin walls and internal baffles, the one or more fin walls comprising one or more inlet openings on one surface of the fin and one or more outlet openings on the opposite surface of the fin. In some embodiments, at least one of the one or more fins comprises an indent proximal to the inner wall and / or outer wall.

[0020] In some embodiments, the apparatus further comprises a plurality of rows of fins, and at least one row of the plurality of rows is arranged such that one or more fins of at least one row do not completely overlap with one or more fins of at least one other row over the length of the first chamber.

[0021] In some embodiments, the apparatus further comprises a plurality of rows, and each pair of adjacent rows has a distance (d) therebetween, and the distance (d) is the same over the entire length of the first chamber.

[0022] In some embodiments, the apparatus comprises a plurality of rows, and each row has a distance (d) between each pair of adjacent rows, and the distance (d) is different between at least two pairs of adjacent rows over the entire length of the first chamber.

[0023] In some embodiments, at least one of the one or more fins is connected to the outer wall of the first chamber by a mechanical interference fit or mechanical fastener.

[0024] In some embodiments, at least one of the one or more fins is integrally structured with the outer wall.

[0025] In some embodiments, at least one of the one or more fins is attached to the outer wall by a second joint.

[0026] In some embodiments, the second joining is welding or brazing.

[0027] In some embodiments, the inner wall further defines a second chamber within the first chamber, and the second chamber has one or more fins disposed therein.

[0028] In some embodiments, one or more fins extend from a first chamber into a second chamber.

[0029] In a second aspect, the present invention provides a system for producing purified hydrogen, comprising one or more apparatuses according to the first aspect and its embodiments, and further comprising a gas separator in fluid communication with one or more apparatuses for separating hydrogen gas from other gases.

[0030] In a third aspect, the present invention provides a system for generating electrical energy, comprising the system of the second aspect and further comprising a fuel cell. [Brief explanation of the drawing]

[0031] [Figure 1] Figure 1A shows a cross-sectional view of an exemplary apparatus according to the present invention. Figure 1B shows a cross-sectional view from the side. [Figure 2]Figure 2A shows an internal view of a section of an exemplary apparatus according to an embodiment of the present invention. Figure 2B shows a side view. Figure 2C shows a top view. [Figure 3] Figure 3A shows an internal view of an alternative part of an exemplary apparatus according to an embodiment of the present invention. Figure 3B shows a side view. Figure 3C shows a top view. [Figure 4] An exemplary fin according to the present invention is shown. Figure 4A shows a side view of a fin having a planar profile. Figure 4B shows side views of fins having various profiles. Figure 4C shows a top view of a fin having two indentations proximal to the inner wall. [Figure 5] Figure 5A shows an exemplary hollow fin according to an embodiment of the present invention. Figure 5A shows a 3D cross-sectional view. Figure 5B shows a top view. Figure 5C shows a side cross-sectional view. [Figure 6] An internal side view of a section of an exemplary apparatus according to an embodiment of the present invention in which the fins do not overlap is shown. [Figure 7] Figure 7A shows internal side views of two sections of an exemplary apparatus according to an embodiment of the present invention. Figure 7A shows an apparatus in which all rows are at equal distances from their adjacent rows. Figure 7B shows an apparatus in which the rows are at different distances from their adjacent rows. [Figure 8] The image shows a side cross-sectional view of an exemplary apparatus according to some embodiments of the present invention, having a second internal chamber and one or more internal fins disposed within the second chamber. [Figure 9] An alternative section of an exemplary apparatus according to an embodiment of the present invention is shown as a side view. [Figure 10] The image shows a side cross-sectional view of an exemplary apparatus according to several embodiments of the present invention, which has a second internal chamber and one or more internal fins located within the first chamber and extending only from the inner wall. [Figure 11] The image shows a side cross-sectional view of an exemplary apparatus according to several embodiments of the present invention, which has a second internal chamber and one or more internal fins arranged within the first and second chambers and extending only into both chambers from the inner wall. [Figure 12] The present invention is shown as part of a system including a gas separator and a hydrogen fuel cell. [Modes for carrying out the invention]

[0032] In a first aspect, the present invention provides a hydrogen generation apparatus for generating hydrogen-rich gas from ammonia, the apparatus comprising a first chamber having an inner wall and an outer wall defining an internal volume, the first chamber containing an ammonia decomposition catalyst disposed between the inner wall and the outer wall, the first chamber having one or more ammonia gas inlets and one or more untreated decomposition gas outlets, the one or more ammonia gas inlets and the one or more untreated decomposition gas outlets are arranged such that the ammonia flows through the first chamber from the one or more ammonia gas inlets to the one or more untreated decomposition gas outlets and into contact with the ammonia decomposition catalyst, the first chamber having one or more fins, the one or more fins disposed between the inner wall and the outer wall of the first chamber, the first chamber having an internal surface area, the internal volume being between 10 ml and 100 liters, mm 3 mm 2 The ratio of the internal surface area of ​​the unit is between approximately 1:2 and 1:6.

[0033] Patent Document 2 relates to a process for generating hydrogen from gaseous ammonia and recycling a portion of the hydrogen to heat the reaction. A conventional tubular ammonia decomposition apparatus is shown (see Figure 3), but it does not disclose the advantageous architecture of the present invention.

[0034] Patent Document 3 discloses a catalyst "slab" reformer in which pins and fins extend through all the inner walls of the apparatus (see Figure 4 of Patent Document 3). Patent Document 3 does not disclose the advantageous architecture of the present invention.

[0035] Patent Document 4 discloses an apparatus for producing hydrogen from gaseous ammonia, intended for household use. This is a conventional ammonia decomposition apparatus, and Patent Document 4 does not disclose any of the advantageous architectures of the present invention.

[0036] Referring to the present invention, the first chamber comprises an outer wall and an inner wall defining the internal volume in which the ammonia reaction decomposition takes place. The first chamber is airtight to the external atmosphere except for one or more ammonia gas inlets and one or more untreated decomposed gas outlets. The first chamber can take any shape depending on the specific requirements for its installation and the assumed use case. Inside the chamber is an ammonia decomposition catalyst, which catalyzes the conversion of ammonia into untreated decomposed gas containing nitrogen and hydrogen as ammonia gas flows through the chamber from one or more ammonia gas inlets and exits through one or more untreated decomposed gas outlets. The untreated decomposed gas essentially consists of a mixture of hydrogen gas, nitrogen gas, and ammonia gas. The ammonia gas in the untreated decomposed gas is ammonia that does not decompose into nitrogen and hydrogen as it passes through the first chamber. Many suitable catalysts are known in the art. For example, supported single-metal catalysts (e.g., Fe, Ru, Cu, Ni, Ir, Co, Mo, Pt, and Pd), polymetallic or alloy catalysts (e.g., Ni-Pt, Ni-Co, Ir-Ni, Co-Mo, Fe-Co, Fe-Mo, Cu-Zn), nitride and carbide catalysts (e.g., carbides and nitrides of Mo, Fe, Co, Ni, Ti, V, Mn, and Cr), and metal amide / imide catalysts (e.g., LiNH2, NaNH2, KNH2) may be used in the present invention. The catalyst is located between the inner and outer walls of the first chamber. The catalyst may be deposited directly onto the inner surface of the chamber, and / or deposited on a suitable substrate and then placed inside the chamber. In one embodiment, the ammonia decomposition catalyst is coated onto the inner surface of the inner and / or outer wall. For clarity, the inner surface is an inwardly facing surface and may include the entire surface of one or more fins. This may be the surface of the inner wall facing the first chamber and one or more fins, and / or the surface of the outer wall facing the first chamber. In another embodiment, the ammonia decomposition catalyst is provided on a separate substrate that at least partially fills the internal volume of the first chamber.In further embodiments, the ammonia decomposition catalyst is provided on a separate substrate that is coated on the inner surface of the inner wall (including the surface of the fins) and / or the outer wall (including the surface of the fins) and at least partially fills the internal volume of the first chamber. One or more ammonia inlets, one or more raw decomposition gas outlets, and the ammonia decomposition catalyst are arranged such that, in use, ammonia gas flows into one or more ammonia inlets, the ammonia gas comes into contact with the ammonia decomposition catalyst, flows through the apparatus, is converted into raw decomposition gas containing hydrogen and nitrogen, and the raw decomposition gas containing hydrogen and nitrogen flows out of one or more raw decomposition gas outlets. Whenever the term “ammonia gas” is used throughout this specification, it means a mixture of gases containing ammonia in its gaseous form. In other words, an ammonia-containing gas. Such a gas may have any other number and / or proportion of other components, as long as it contains ammonia in its gaseous form.

[0037] The ammonia decomposition reaction, being in equilibrium, favors lower pressures and higher temperatures. However, these conditions are in contrast to designing and constructing an efficient and commercially viable ammonia cracker, where a compromise set of conditions is selected to yield sufficient ammonia conversion at the lowest temperature and pressure suitable for downstream processes. For example, the reaction may be at a temperature of 400–950°C and a pressure of any of 0.1–40 barg. Typically, one or more heat sources are provided to heat the apparatus to the optimal temperature for the selected pressure. For example, one or more heat sources may be an additional hot gas stream, an electric induction heater, a radiant heater, a resistance heater, a combustion heater, or a combination of any of the above. To provide good heat transfer throughout the entire internal volume of the first chamber, the chamber has one or more fins positioned between the inner and outer walls, as described below. One or more heat sources can heat the apparatus from the inside (in other words, the heat sources are near the inner wall). As an addition or alternative, a heat source can heat the apparatus from the outside (in other words, the heat source is near the outer wall). A combined approach can also be employed. Regardless of the arrangement of one or more heat sources, one or more fins function to conduct heat throughout the entire internal volume of the first chamber. One or more heat sources heat the inner wall, outer wall, and fins, and ultimately heat the ammonia decomposition catalyst and ammonia gas to the required temperature to decompose the ammonia gas flowing through the first chamber. If the ammonia decomposition catalyst is placed on a separate substrate that at least partially fills the internal volume, heat can be transferred from the inner wall, outer wall, and one or more fins to the substrate, allowing the reaction to proceed.

[0038] An exemplary apparatus according to the present invention has an annular structure and is shown in Figure 1, where an inner wall 102 forms a first cylinder and an outer wall 103 forms a second cylinder, the first cylinder is located inside the second cylinder, and a reaction chamber is formed between the inner wall 102 and the outer wall 103. Figure 1A shows a side cross-sectional view. Figure 1B shows a top cross-sectional view. As shown, the apparatus 100 is annular and has an inner wall 102 and an outer wall 103 defining a first chamber 101. The inlet and outlet are not shown in the cross-sectional view. The ammonia decomposition catalyst 104 is placed in the first chamber as a coating on the inner surfaces of the inner and outer walls. Furthermore, there are one or more fins 105 extending from the inner and outer walls, although in other embodiments, one or more fins may extend only from the inner wall. A heat source 106 is provided and is arranged to heat the ammonia decomposition catalyst in the first chamber.

[0039] The inner and outer walls may include or be constructed from any suitable material, but in some embodiments, metal is preferred. The chamber is preferably constructed from austenitic stainless steel or a high nickel-chromium superalloy. These materials are resilient at the temperatures and pressures at which decomposition occurs and have excellent thermal conductivity. In some embodiments, one or more fins may be constructed from the same material as the inner and / or outer walls. In some embodiments, one or more fins may be made from a different material than the inner and / or outer walls. This is advantageous, for example, when the fins need to have better thermal conductivity than the inner or outer walls of the first chamber. In one embodiment, at least one of the one or more fins is attached to and / or extends from the inner wall. This means that the fin is physically connected to and / or in physical contact with the inner wall. In one embodiment, one or more fins and the inner wall are integral structures. This means that there is no defined material boundary between the inner wall and the one or more fins. For example, if the inner wall and one or more fins are made by die casting, they are integral structures. This has the advantage of excellent heat transfer between the inner wall and each of the one or more fins, because defects at the joint between the two structures can be ignored. In some embodiments, one or more fins are manufactured as separate entities and attached to the inner wall of the first chamber. For example, they may be attached as mechanical interference fits or using mechanical fasteners such as clips or rivets. In some embodiments, one or more fins are attached to the inner wall by adhesive. This means that one or more fins are manufactured separately and joined to the inner wall by, for example, welding or brazing. In some embodiments, the fins may extend through the width of the first chamber so as to contact the outer wall of the first chamber. In some embodiments, the fins may extend only to a certain point in the width of the first chamber so as not to contact the outer wall. This is advantageous because it prevents heat loss from the outer wall to the environment.

[0040] In some embodiments, there are multiple fins, as shown in Figure 1. Those skilled in the art will assume that the chamber may have a single fin that extends along the length of the first chamber, providing a heat transfer surface, a substrate for the ammonia decomposition catalyst, and can influence the gas flow. However, having multiple fins allows for further customization of the gas flow path through the first chamber and is therefore advantageous. The first chamber has an internal volume and an internal surface area. The internal surface area is defined by the inner-facing surfaces of the inner wall of the (first) chamber and the surfaces of one or more fins. In other words, the internal volume of the ammonia cracker is between 10 ml and 100 liters (optionally between 10 ml and 40 liters), and the surface area (mm²) of the inner wall and the inner surfaces of one or more fins. 2 Units) and internal volume (mm 3 The ratio of ) to is 1:2 to 1:6, preferably about 1:2, 1:3, 1:4, 1:5, or 1:6.

[0041] The applicants have surprisingly found that a particular surface area-to-volume ratio is particularly advantageous for ammonia decomposition reactors operating in volumes from 10 ml to 100 liters. In some embodiments, the internal volume of the ammonia cracker is between 10 ml and 100 liters, preferably between 10 ml and 40 liters, more preferably between 1 liter and 30 liters, more preferably between 1 liter and 20 liters, and the internal surface area (mm² 2 ) and internal volume (mm 3 The ratio of ) to is between approximately 1:2 and 1:6. Preferably, the ratio is approximately 1:2, 1:3, 1:4, 1:5, or 1:6. Such ratios have the effect of maximizing heat transfer from the heat source to the catalyst substrate and / or ammonia decomposition catalyst.

[0042] In an alternative embodiment, the internal surface area may be defined by the surfaces facing the inside of the inner and outer walls of the (first) chamber and the surfaces of each of the one or more fins. In such an embodiment, the internal volume of the ammonia cracker is between 10 ml and 100 liters, preferably between 10 ml and 40 liters, more preferably between 1 liter and 30 liters, more preferably between 1 liter and 20 liters, and even more preferably between 2 liters and 5 liters, and the internal surface area (mm 2 ) to internal volume (mm 3 ) ratio is between about 1:0.8 and 1:6. Preferably, the ratio is about 1:0.8, :0.9, 1:1, 1:2, 1:3, 1:4, 1:5 or 1:6. As described above, such a ratio has the effect of maximizing heat transfer from the heat source to the catalyst substrate and / or the ammonia decomposition catalyst.

[0043] In some embodiments, multiple fins are arranged as one or more helices along the entire length of the first chamber. Figure 2 shows a small section of such an arrangement in a 3D view (A) excluding the outer wall, and in a side view (B) and a top view (C). In such an arrangement, the fins 205 are not aligned with the horizontal axis, but instead spiral down the inner wall 202 in the direction of the length of the first chamber. In some embodiments, two or more such fin helices may be present, which can further alter the gas flow characteristics. The illustrated helical arrangement has the advantage of increasing gas retention because it increases the path length of the gas flowing through the reactor and introduces some additional turbulence, as the gas tends to flow spirally, and following the fins through the first chamber, the gas can absorb further heat from an external heat source. In some embodiments, one or more fins may be arranged as two helices along the length of the first chamber, one spiraling clockwise and the other counterclockwise. This arrangement has the advantage of slowing the flow and increasing the gas residence time in the first chamber by increasing the turbulence of the gas flow. Those skilled in the art will understand that, in some cases, a combination of the two approaches can be taken by providing one section configured as a single helix of fins to accelerate the gas flow in one section of the first chamber, and a further section configured as two helices, one clockwise and one counterclockwise, to decelerate the gas.

[0044] In some embodiments, multiple fins are arranged on the inner wall in one or more rows, with each fin in each row parallel to each other in the same row on a plane substantially perpendicular to the length of the first chamber. Figure 3 shows a small section of such an arrangement in a 3D view (A) excluding the outer wall, and in a side view (B) and a top view (C). As shown, there are three rows of fins 305 arranged on the inner wall 302, each row defined (indicated by arrows) by the alignment of the fins in that row along a plane h perpendicular to the gas flow in use. Having such a regular structure allows for uniform control of the gas flow through the section of the first chamber.

[0045] In some embodiments, each fin of a plurality of fins has the same angle to one another, as shown, for example, in Figure 3. As shown in Figure 4, angle a is the angle between a plane h perpendicular to the gas flow in use and the bottom surface of the fin. (A) shows a fin 405 positioned on an inner wall 402, which has a flat profile, and (B) shows a fin 405 positioned on an inner wall 402, which has a profile that varies along its entire length. If the fins have varying profiles, angle a is measured as the average over the length of the fin. In some embodiments, at least one fin of the plurality of fins has a different angle to at least one other fin. By adjusting the angle of any one fin, the effect on the gas flow path can be adjusted, thus allowing for fine control of the gas flow through the first chamber. In some embodiments, at least one fin of a plurality of fins having a different angle to at least one other fin is in the same row as at least one other fin. In some embodiments, the plurality of fins are arranged as at least two rows, and at least one fin of the plurality of fins having a different angle to at least one other fin is in a different row from at least one other fin. In exemplary embodiments, each row of fins in a plurality of fins has an angle opposite to the angle of the fins in the adjacent row. An exemplary configuration is shown in Figure 9. In this arrangement, the angles of the fins in the first and third rows 905 orient the fin faces in one direction, while the angles of the fins in the second row 914 orient the fin faces in the opposite direction. Such a configuration increases the gas residence time. Naturally, a combination of these two approaches can be employed so that the angle of any fin can vary relative to other fins on that row or on different rows. This customizability of the device allows for optimal engineering of the gas flow for any given installation or use case.For example, the angle of each fin can be selected from the group consisting of angles substantially perpendicular to the length of the first chamber (i.e., along the previously defined plane), substantially parallel to the length of the chamber (i.e., perpendicular to the previously defined plane h), and / or angles between substantially perpendicular or substantially parallel to the length of the chamber (in other words, between the two angles mentioned above).

[0046] As described above and as shown in Figure 4, each fin may have a substantially flat or varying profile along its entire length. Fins of different shapes provide a further degree of control over local gas flow characteristics, thus enabling very precise control of gas residence time and velocity. Any combination of fin shapes is envisioned, either alone or in combination, for the purposes of the present invention. In some embodiments, at least one of one or more fins has one or more openings and / or one or more protrusions and / or one or more recesses on its surface. These variations increase the total surface area of ​​the fin, increasing the reaction surface when the fin is coated with the catalyst, and enabling further precise control of local gas flow. The fins may be etched, engraved, or roughened to form the protrusions and / or recesses. In some embodiments, each fin may be shaped to provide a flow path proximal to the inner and / or outer walls. This is achieved by removing a portion of the fin proximal to the inner and / or outer walls, thus allowing gas to flow proximal to the inner and / or outer walls. Such a shape is sometimes described as a fin with an "indentation." An exemplary fin of this embodiment is shown in Figure 4C, where the fin 405 has two indentations 407 proximal to the inner wall 402.

[0047] In some embodiments, at least one fin may be a hollow fin comprising a subchamber defined by one or more fin walls with an internal baffle, the one or more fin walls comprising one or more inlet openings on the face of the fin and one or more outlet openings on the face opposite the fin. An exemplary hollow fin 505 is shown in Figure 5, where Figure 5A shows a 3D cross-sectional view of the fin, Figure 5B shows a top view, and Figure 5C shows a side cross-sectional view. In this exemplary embodiment, one or more fin walls 508 of the subchamber define a subchamber volume 509 having an internal baffle 510 therein. Gas flows in through one or more inlet openings 511, passes through the subchamber volume 509 around the internal baffle 510, and then flows out through one or more outlet openings 512. In some embodiments, the hollow fin extends substantially to the width of the first chamber and consequently substantially contacts either the inner wall 502 (when mounted on the inner wall) or the outer wall 503 (when mounted on the inner wall), and therefore the gas flow must occur through the sub-chamber volume 509 of the hollow fin. This is advantageous in the present invention because such a hollow fin provides further control over the gas residence time and generates turbulence by pushing the gas down into a defined path.

[0048] In some embodiments, the apparatus comprises multiple rows of fins, where at least one row is arranged such that one or more fins of at least one row do not completely overlap with one or more fins of at least one other row of the multiple rows over the length of the first chamber. Figure 6 shows an exemplary embodiment of such an apparatus. In the illustrated section, three rows of fins 605 are arranged on the inner wall 602, but they do not completely overlap each other. As gas flows through this section, it is forced to move around the fins because there is no direct flow path from the inlet side to the outlet side of the chamber. This provides further customization of the flow paths within the apparatus, allowing for more precise control of gas velocity and stagnation in any one section of the first chamber. To further provide turbulence, one or more fins in each row can be set at an angle substantially perpendicular to one or more fins in an adjacent row so as to increase gas turbulence. As shown in Figure 9, it is assumed that at least one row is positioned such that one or more fins in each row are at a substantially perpendicular angle to one or more fins in an adjacent row, and that one or more fins in at least one row do not completely overlap with one or more fins in at least one other row of the multiple rows over the length of the first chamber. In fact, each adjacent row may be angled and offset in this manner relative to its adjacent row.

[0049] In some embodiments, the apparatus comprises multiple rows having a distance d between each pair of adjacent rows, and this distance remains the same throughout the length of the first chamber. In some embodiments, the apparatus includes multiple rows, each row having a distance (d) between each pair of adjacent rows, and the distance d differs between at least two pairs of adjacent rows throughout the length of the first chamber. Figure 7 shows a cross-section of an inner wall 702 with three rows of fins 705 arranged therein, where the distance d is calculated as the distance between the fins of each row in the gas flow direction indicated by the arrows. In Figure 7A, the distance d is the same between each pair of rows. In Figure 7B, the distance d differs between the first pair of rows and the second pair of rows. By spacing the rows in this way, the gas velocity and gas residence time in any one section of the apparatus can be further controlled. The applicants have found that the apparatus can be improved by having a section of the chamber toward one or more ammonia gas inlets where the spacing between rows is narrower (i.e., the distance d is smaller) compared to the downstream section. In any case, varying the distance between the rows of fins allows for multiple designs that can be adapted to specific functions of the first chamber.

[0050] In some embodiments, at least one of the one or more fins is connected to the outer wall of the first chamber by a mechanical interference fit or mechanical fastener. In some embodiments, at least one of the one or more fins is integral with the outer wall. In some embodiments, at least one of the one or more fins is attached to the outer wall by a second joint, preferably by welding or brazing. To carry out the present invention, any combination of the above may also be used, along with any combination of one or more fins connected to the inner wall as described above.

[0051] In some embodiments, the inner wall of the apparatus defines a second chamber, and the second chamber has one or more fins disposed therein. These fins, individually or in combination, can have any of the characteristics described above. In one embodiment of the present invention, one or more fins extend from the first chamber into the second chamber. This provides optimal heat transfer characteristics between the first and second chambers. As shown in Figure 8, a heat source can be provided in or through the second chamber 813, and the transfer of heat from the second chamber 813 to the first chamber 801 is improved by having one or more fins 805 disposed in the second chamber 813 and the first chamber 801. In some embodiments, at least one of the one or more fins is attached to the inner wall and / or extends from the inner wall. In some embodiments, at least one of the one or more fins extends from the inner wall into the volume of the first chamber. In some embodiments, if the apparatus comprises multiple fins, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of the multiple fins are attached to and / or extend from the inner wall. Such fins optimize heat transfer from the inner portion of the apparatus to the ammonia decomposition catalyst present in the first chamber. In some embodiments, one or more fins are attached to and / or extend from the inner wall; that is, all fins extend from the inner wall into the volume of the first chamber. Such an apparatus is shown in Figure 10. The apparatus comprises a first chamber 1001 and a second chamber 1013, the second chamber providing heat conducted through one or more fins 1005 via an inner wall 1002 shared between the first chamber 1001 and the second chamber 1013. In some embodiments, one or more fins attached to and / or extending from the inner wall extend toward the outer wall, partially traversing the width of the first chamber. In such embodiments, each of the one or more fins has a leading edge, which is the edge of each fin closest to the outer wall, with a gap between the leading edge and the outer wall.In such embodiments, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of one or more fins may extend toward the outer wall, partially traversing the width of the first chamber. In some embodiments, all of one or more fins extend toward the outer wall, partially traversing the width of the first chamber. In practice, in such embodiments, the described proportions of one or more fins each have a leading edge, which is the edge of each fin closest to the outer wall, and each has a gap between the leading edge and the outer wall. In some embodiments, one or more fins may further extend from the inner wall into the volume of the second chamber. In such embodiments, one or more fins are attached to the inner wall or extend from the inner wall. If one or more fins comprise multiple fins, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more of the multiple fins are attached to the inner wall and / or extend from the inner wall. Such a device is shown in Figure 11. The device has a first chamber 1101 and a second chamber 1113, the second chamber providing heat conducted through an inner wall 1102 shared between the first chamber 1101 and the second chamber 1113, and one or more fins 1105 extending from the inner wall assist in transferring this heat into the volume of the first chamber 1001. This is particularly advantageous when the heat source is in the second chamber as described above, or otherwise when the heat is provided near the inner wall, thereby maximizing heat transfer from the inner wall of the device and minimizing heat loss through the outer wall of the device.

[0052] Although the device is shown as an annular device in the figure, those skilled in the art will understand that other geometric shapes can achieve the effects of the present invention without substantial modification. The embodiments described above provide the benefits of the present invention individually or in combination, and all combinations of the embodiments described above are envisioned as part of the present invention.

[0053] The exact shape, size, and number of fins depend on the size of the required device. Similarly, the number of rows of fins required varies depending on the device requirements and the specific application of the device according to the present invention.

[0054] In a further embodiment, the present invention provides a system for producing purified hydrogen, comprising one or more of the apparatus and embodiments of the first embodiment, and further comprising a gas separator for separating hydrogen gas from other gases in fluid communication with one or more of the apparatus. The gas separator may be a pressure swing adsorption device and / or palladium filter, which are known in the art for separating hydrogen from nitrogen and ammonia, but any suitable gas separator may be used. See, for example, Patent Documents 5 and 6 (incorporated herein by reference).

[0055] In a further embodiment, the present invention provides a system for generating electrical energy, comprising the system of the above embodiment and further comprising a fuel cell. Such a system makes it possible to generate electrical energy using hydrogen produced by one or more devices of the first embodiment. Suitable fuel cells are known in the art. See, for example, Patent Document 7 (incorporated herein by reference).

[0056] Figure 12 shows a system having apparatus 1200 according to the present invention, which is in fluid communication with a gas separator 1215 via a common untreated cracked gas conduit 1216. The gas separator is in fluid communication with a hydrogen fuel cell 1217 via a common purified cracked gas conduit 1218. The gas flow is indicated by arrows, showing ammonia gas entering the ammonia cracker 1200 via the inlet. The ammonia gas is cracked into untreated cracked gas containing nitrogen and hydrogen gas, which exits the ammonia cracker and enters the common untreated cracked gas conduit 1216, flowing through the inlet to the gas separator 1215, where nitrogen and any other impurities are removed from the untreated cracked gas to produce purified cracked gas consisting essentially of hydrogen. The purified cracked gas exits the gas separator via the outlet and is carried to the hydrogen fuel cell 1217 via the common purified cracked gas conduit 1218, where the hydrogen is used with oxygen gas to generate electricity.

[0057] In further aspects of the present invention, the apparatus for producing hydrogen may be a steam reformer, for example, a hydrocarbon steam reformer, or another thermal catalytic decomposition reactor having any of the features and embodiments of the first aspect.

Claims

1. A hydrogen generator for producing hydrogen-rich gas from ammonia, A first chamber comprising an inner wall and an outer wall defining the internal volume, wherein the first chamber includes an ammonia decomposition catalyst disposed between the inner wall and the outer wall, and the first chamber has one or more ammonia gas inlets and one or more untreated decomposition gas outlets, wherein the one or more ammonia gas inlets and the one or more untreated decomposition gas outlets are arranged such that the ammonia flows through the first chamber from the one or more ammonia gas inlets to the one or more untreated decomposition gas outlets and into contact with the ammonia decomposition catalyst, One or more heat sources for heating the ammonia decomposition catalyst, Equipped with, The first chamber has one or more fins, and the one or more fins are arranged between the inner wall and the outer wall of the first chamber. The first chamber has an internal surface area, and its internal volume is between 10 ml and 100 liters, mm ３ mm as a unit of the internal volume ２ An apparatus in which the ratio of the internal surface area of ​​the units is between approximately 1:2 and 1:

6.

2. The apparatus according to claim 1, wherein at least one of the one or more heat sources is located near the inner wall or near the outer wall.

3. The apparatus according to claim 1 or claim 2, wherein the one or more heat sources comprises at least two heat sources, preferably at least one of which is located near the inner wall and at least one of which is located near the outer wall.

4. The apparatus according to any one of claims 1 to 3, wherein at least one of the one or more fins is attached to and / or extends from the inner wall.

5. The apparatus according to any one of claims 1 to 4, wherein at least one of the one or more fins and the inner wall are integrally structured.

6. The apparatus according to any one of claims 1 to 5, wherein at least one of the one or more fins is attached to the inner wall by mechanical interference fit or mechanical fastener.

7. The apparatus according to any one of claims 1 to 6, wherein at least one of the one or more fins is attached to the inner wall by joining.

8. The apparatus according to claim 6 or 7, wherein the one or more fins are made of a material different from the inner wall or outer wall of the first chamber.

9. The apparatus according to claim 7 or 8, wherein the joining is welding or brazing.

10. The apparatus according to any one of claims 1 to 9, wherein the one or more fins comprises a plurality of fins.

11. The apparatus according to claim 10, wherein at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or more of the plurality of fins are attached to the inner wall and / or extend from the inner wall.

12. The apparatus according to claim 10, wherein the plurality of fins are attached to the inner wall and / or extend from the inner wall.

13. The apparatus according to claim 10, wherein the plurality of fins are arranged as one or more helices along the entire length of the first chamber.

14. The apparatus according to claim 10, wherein the plurality of fins are arranged in one or more rows, and each fin in each row is parallel to each other in the same row on a plane substantially perpendicular to the length of the first chamber.

15. The apparatus according to any one of claims 10 to 14, wherein each fin of the plurality of fins has the same angle to one another.

16. The apparatus according to any one of claims 10 to 14, wherein at least one of the plurality of fins has a different angle from at least one other fin.

17. The apparatus according to claim 16, wherein at least one of the plurality of fins having a different angle from at least one of the other fins is in the same row as the at least one other fin.

18. The apparatus according to claim 16, wherein the plurality of fins are arranged in at least two rows, and at least one of the plurality of fins has a different angle from at least one of the other fins, and is in a different row from at least one of the other fins.

19. The apparatus according to any one of claims 15 to 18, wherein the angle of each fin is selected from the group consisting of an angle substantially perpendicular to the length of the first chamber, a angle substantially parallel to the length of the chamber, and / or an angle between substantially perpendicular and substantially parallel to the length of the chamber.

20. The apparatus according to any one of claims 1 to 19, wherein at least one of the fins has a planar profile.

21. The apparatus according to any one of claims 1 to 20, wherein at least one of the one or more fins has a profile that changes along its entire length.

22. The apparatus according to claim 21, wherein at least one of the one or more fins has one or more openings and / or one or more protrusions and / or one or more recesses on the surface of the at least one fin.

23. The apparatus according to any one of claims 1 to 22, wherein at least one of the one or more fins is a hollow fin having a sub-chamber defined by one or more fin walls and an internal baffle, and the one or more fin walls have one or more inlet openings on the surface of the fin and one or more outlet openings on the surface opposite to the fin.

24. The apparatus according to any one of claims 1 to 23, wherein at least one of the one or more fins is provided with an indentation near the inner wall and / or the outer wall.

25. The apparatus according to any one of claims 14 to 24, further comprising a plurality of rows, wherein at least one of the plurality of rows is arranged such that one or more fins of the at least one row do not completely overlap with the one or more fins of the other at least one of the plurality of rows over the length of the first chamber.

26. The apparatus according to any one of claims 14 to 25, comprising a plurality of rows, wherein each pair of adjacent rows has a distance (d) between them, and the distance (d) is the same over the entire length of the first chamber.

27. The apparatus according to any one of claims 14 to 25, comprising a plurality of rows, each row having a distance (d) between each pair of adjacent rows, wherein the distance (d) differs between at least two pairs of adjacent rows over the entire length of the first chamber.

28. The apparatus according to any one of claims 1 to 27, wherein at least one of the one or more fins is connected to the outer wall of the first chamber by a mechanical interlocking fit or a mechanical fastener.

29. The apparatus according to any one of claims 1 to 28, wherein at least one of the one or more fins is integrally structured with the outer wall.

30. The apparatus according to any one of claims 1 to 29, wherein at least one of the one or more fins is attached to the outer wall by a second joint.

31. The apparatus according to claim 30, wherein the second joining is welding or brazing.

32. The apparatus according to any one of claims 1 to 31, wherein the inner wall further defines a second chamber within the first chamber, and the second chamber has one or more fins disposed therein.

33. The apparatus according to claim 32, wherein one or more fins extend from the first chamber into the second chamber.

34. A system for producing purified hydrogen, comprising one or more devices according to any one of claims 1 to 33, and further comprising a gas separator in fluid communication with the one or more devices for separating hydrogen gas from other gases.

35. A system for generating electrical energy, comprising the system described in claim 34, and further comprising a fuel cell.

Images