Apparatus for performing endothermic reaction of gas feed
The apparatus integrates pre-reaction and main reaction stages with radiant and convective heating, optimizing heat transfer and reducing excess heat load, addressing complexity and space issues in endothermic reaction systems.
Patent Information
- Application Number
- JP2025039932
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-03-20
- Filing Date
- 2025-03-13
- Publication Date
- 2025-10-03
AI Technical Summary
Existing endothermic reaction systems require additional equipment like separate pre-reactors and associated piping, increasing complexity and space requirements.
An apparatus with a preheater, reactor tube, and furnace that integrates pre-reaction and main reaction stages, using radiant and convective heating, and heat exchanger channels to optimize heat transfer and reduce excess heat load without additional equipment.
Reduces heat load on the main reactor, enhances conversion rates, and simplifies equipment layout by integrating pre-reaction and main reaction stages within a single unit.
Smart Images
Figure 2025146733000001_ABST
Abstract
Description
[Technical Field]
[0001] [1] The present invention relates to an apparatus for carrying out an endothermic reaction of a gas feed. The present invention also relates to the use of the apparatus for such an endothermic reaction. [Background technology]
[0002] [2] Endothermic processes are known for producing synthesis gas from hydrocarbon feedstocks. Synthesis gas can be useful for the production of ammonia or hydrogen, among other things. Endothermic processes for splitting ammonia into hydrogen and nitrogen are also known to recover hydrogen from the ammonia. The recovered hydrogen has much better combustion properties than ammonia itself and is suitable for industrial use or as a transportation fuel. A typical reformer or cracker unit usually contains one or more tubes filled with a catalyst that is heated by combustion.
[0003] [3] It is known to have a pre-reaction step of the gas feed, such as a pre-reforming or pre-cracking step, followed by a main reaction step in a main reactor, such as a main reforming or main cracking step. The pre-reaction step makes it possible to reduce the heat load in the main reactor for heat input to the endothermic process. Prior art systems usually use a simple adiabatic pre-reactor for the pre-reaction step, separate from the main reactor. The endothermic reaction heat is provided via a preheated gas feed.
[0004] [4] However, such a system requires additional equipment, including a separate pre-reactor and associated piping, which requires more compartment space and is more complex. Summary of the Invention
[0005] [5] The present invention relates to an apparatus for endothermic reaction of a gas feed, the apparatus comprising: a preheater arranged to preheat the gas supply; at least one reactor tube; a furnace arranged to radiatively and / or convectively heat the at least one reactor tube; The at least one reactor tube is at least partially filled with a catalytic material configured to promote an endothermic reaction, and the at least one reactor tube comprises: - a pipe inlet for said preheated gas feed; a main reactor tube section extending into the furnace and a preliminary reactor tube section extending outside the furnace, the preliminary reactor tube section being disposed between the tube inlet and the main reactor tube section; A portion of the catalyst material extends into the pre-reactor tube section.
[0006] [6] The preheated gas feed entering the pre-reactor section is pre-reacted in an endothermic pre-reaction over the catalyst filling the pre-reactor section. As a result, the heat load from the furnace to the main reactor section can be reduced, thereby reducing excess heat from the furnace. The present invention provides such pre-reaction and its benefits without the need for the additional equipment of the prior art, which makes such additional equipment optional.
[0007] [7] The furnace is particularly arranged to provide radiant and / or convective heating of the main reactor tube section.
[0008] [8] In one embodiment, the pre-reactor tube section is configured to partially react the pre-heated gas feed in a pre-reaction, thereby obtaining a partially reacted gas, and the main reactor tube section is configured to further react the partially reacted gas in a main reaction.
[0009] [9] In one embodiment, the length of the pre-reactor tube section is 30-80% of the total length of the reactor tube. In particular, the length of the pre-reactor tube section is 4-10 meters, and the total length of the reactor tube is 12-18 meters.
[0010]
[10] In one embodiment, the furnace includes a radiant and convective chamber surrounding the main reactor tube section for radiant and / or convective heat transfer to the main reactor tube section. The pre-reactor tube section extends outside the radiant and convective chamber. In particular, the radiant and convective chamber is a continuous chamber surrounding the main reactor tube section. The radiant and convective chamber may be defined by a refractory material.
[0011]
[11] In one embodiment, the furnace comprises an electric heater arranged to heat the at least one reactor tube, particularly the electric heater being arranged within the radiation and convection chamber.
[0012]
[12] In one embodiment, the apparatus, particularly the at least one reactor tube, comprises at least one heat exchanger channel arranged to discharge product gas produced by the endothermic reaction from the at least one reactor tube and to transfer heat from the product gas, particularly from the discharged product gas, to at least a portion of the catalytic material. In particular, the at least one heat exchanger channel is arranged inside the at least one reactor tube. Preferably, the at least one heat exchanger channel extends through at least a portion of the catalytic material inside the at least one reactor tube. The at least one heat exchanger channel has, for example, a straight shape, an at least partially coiled shape, or an at least partially helical shape.
[0013]
[13] In one embodiment, at least one heat exchanger channel is arranged to discharge product gas in countercurrent to the gas feed and product gas circulating within the catalyst material.
[0014]
[14] In one embodiment, the portion of the catalytic material that extends into the pre-reactor tube section is an upstream portion of the catalytic material.
[0015]
[15] In one embodiment, the at least one heat exchanger channel is positioned to transfer heat from the product gas, particularly from the discharged product gas, to at least a portion of the upstream portion of the catalytic material. In the latter embodiment, the apparatus enables the hot product gas discharged through the at least one heat exchanger channel to provide heat to an endothermic pre-reaction of the gas feed in the upstream portion of the catalytic material, thereby increasing the conversion rate of the pre-reaction. In particular, the at least one heat exchanger channel extends inside the at least one reactor tube through at least a portion of the upstream portion of the catalytic material.
[0016]
[16] In one embodiment, the at least one heat exchanger channel is arranged to transfer heat from the product gas, particularly from the vented product gas, to only a portion of the upstream portion of the catalytic material. The degree of heating of the upstream portion of the catalytic material, and therefore the degree of pre-reaction conversion, can be adjusted in this way. In particular, the at least one heat exchanger channel extends inside the at least one reactor tube through only a portion of the upstream portion of the catalytic material.
[0017]
[17] In one embodiment, the portion of the catalytic material extending into the pre-reactor section is an upstream portion of the catalytic material, and the downstream portion of the catalytic material extends into the main reactor section.
[0018]
[18] In one embodiment, the upstream portion of the catalytic material has a lower catalytic activity temperature than the downstream portion of the catalytic material. For example, the upstream portion comprises a different active material than the active catalytic material in the downstream portion and / or the upstream portion comprises a higher content of active catalytic material than the downstream portion. In particular, the upstream portion comprises an active material having a lower catalytic activity temperature compared to the active catalytic material in the downstream portion.
[0019]
[19] In one embodiment, the at least one heat exchanger channel extends through the downstream portion of the catalytic material and through at least a portion of the upstream portion of the catalytic material. In particular, the at least one heat exchanger channel extends through only a portion of the upstream portion of the catalytic material. In one embodiment, the at least one heat exchanger channel has a first shape in the downstream portion and a second shape in the upstream portion that is different from the first shape. For example, the at least one heat exchanger channel may have a straight tube shape in the downstream portion and a coil or spiral shape in the upstream portion. Conversely, the at least one heat exchanger channel may have a coil or spiral shape in the downstream portion and a straight tube shape in the upstream portion.
[0020]
[20] In one embodiment, at least one heat exchanger channel is positioned to transfer heat from the product gas, particularly from the vented product gas, to only a downstream portion of the catalytic material. In this embodiment, preheating of the gas feed is sufficient to perform the pre-reaction, and the upstream portion of the catalytic material has a temperature profile similar to that of the catalytic material of an adiabatic reactor. In particular, at least one heat exchanger channel extends inside at least one reactor tube through only a downstream portion of the catalytic material.
[0021]
[21] In one embodiment, the apparatus comprises at least one inlet header connected to the at least one reactor tube inlet for supplying a preheated gas feed to the at least one reactor tube.
[0022]
[22] In one embodiment, the apparatus includes at least one outlet header connected to the at least one heat exchanger channel for discharging product gas produced by the endothermic reaction from the at least one heat exchanger channel.
[0023]
[23] In one embodiment, the apparatus includes a fuel and combustion oxidant system arranged to combust a fuel with an oxidant gas inside a furnace. In particular, a radiant and convection chamber is arranged to provide heat from the fuel and combustion oxidant system to a main reaction section of the at least one reactor tube by radiant and / or convective heat transfer. The fuel and combustion oxidant system typically includes at least one burner nozzle opening into the radiant and convection chamber.
[0024]
[24] In one embodiment, the apparatus includes an equipment chamber separate from the furnace, the equipment chamber including at least a portion of the fuel and combustion oxidant system, and / or the at least one inlet header and / or the at least one outlet header. In particular, the equipment chamber is free of refractory material.
[0025]
[25] In one embodiment, the furnace is defined by a furnace wall, particularly from the equipment chamber, and the preliminary reactor tube section is defined by the furnace wall from the main reactor tube section. In particular, the fuel and combustion oxidant system are attached to the furnace wall. The furnace wall is preferably lined with a refractory material on the furnace side. The furnace wall is typically the top wall of the furnace.
[0026]
[26] In one embodiment, at least one inlet header and / or at least one outlet header is attached to the apparatus above the at least one reactor tube.
[0027]
[27] Compared to prior art reformers, the inlet and / or outlet headers can be located near the tip of the at least one reactor tube, away from the fuel and combustion oxidant systems, which are located near the boundary between the pre-reactor tube section and the main reactor tube section where the furnace begins. This allows for more convenient spatial integration and construction of each of these elements.
[0028]
[28] In one embodiment, the furnace is a top-fired furnace and the preliminary reactor tube section is an upper section of the at least one reactor tube.
[0029]
[29] In one embodiment, the apparatus includes a plurality of reactor tubes, each including a catalytic material configured to promote an endothermic reaction. A furnace is configured to radiantly and / or convectively heat each of the reactor tubes. Each of the plurality of reactor tubes includes a tube inlet for a preheated gas feed, a main reactor tube section, and a pre-reactor tube section disposed between the tube inlet and the main reactor tube section. Each of the pre-reactor tube sections extends outside the furnace, and each of the main reactor tube sections extends into the furnace. A portion of each of the catalytic material extends into the pre-reactor tube section.
[0030]
[30] In one embodiment, the apparatus, particularly each of the plurality of reactor tubes, includes a plurality of heat exchanger channels arranged to discharge product gas produced by the endothermic reaction from each of the plurality of reactor tubes and to transfer heat from the product gas to at least a portion of the catalytic material. In particular, each of the plurality of heat exchanger channels is arranged inside each of the plurality of reactor tubes. Preferably, each of the plurality of heat exchanger channels extends through at least a portion of the catalytic material inside each of the plurality of reactor tubes. The plurality of heat exchanger channels has, for example, a coil shape or a spiral shape.
[0031]
[31] The present invention also relates to the use of the above-described apparatus for the decomposition reaction of the gas feed, i.e., an ammonia feed, in which the preliminary reactor section is arranged to carry out a preliminary decomposition reaction of a preheated ammonia feed, thereby obtaining a partially converted ammonia stream, and the main reactor section is arranged to carry out a further decomposition reaction of the partially converted ammonia stream into a cracked gas containing hydrogen, nitrogen, and optionally unconverted ammonia.
[0032]
[32] The present invention also relates to the use of the above-described apparatus for converting a hydrocarbon feed into hydrogen containing synthesis gas.
[0033]
[33] Other features, details and advantages of the present invention will become apparent from the detailed description set forth below, together with some embodiments thereof, given by way of example and indication only, and with reference to the accompanying schematic drawings, in which: [Brief explanation of the drawings]
[0034] [Figure 1]
[34] Figure 1 shows an apparatus for carrying out an endothermic process according to the prior art. [Figure 2] 1 illustrates an apparatus of the present invention according to one embodiment. [Figure 3] 3 shows further details of the embodiment of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION
[0035]
[35] A prior art reformer is shown in FIG. 1. The reformer comprises one or more catalyst-filled reactor tubes 2 extending through a furnace 1. Each tube comprises an inlet (not shown) and catalytic material 10 (represented by hatching in the drawing). The reformer is a top-fired reformer, with burners 3, part of a fuel and combustion oxidant system, mounted on top of the furnace 1. The burners 3 heat the furnace 1 and drive the endothermic reforming reaction. A penthouse equipment chamber 4 contains inlet and outlet headers 5 and 6 for supplying hydrocarbon feed to the tubes 2 and for exhausting synthesis gas produced by the endothermic reaction. A combustion air header 7 is housed in the same penthouse chamber 4 and supplies combustion air, an oxidant gas, to the burners for combustion of the fuel. Fuel is supplied to the burners 3 via fuel header 8. For simplicity, only one inlet header 5, one outlet header 6, one combustion air header 7, and two fuel headers 8 are shown. The nozzle of the burner 3 is aimed into the interior of the furnace 1, generating a flame inside the furnace 1. The interior of the furnace 1 constitutes a radiant and convective chamber where convective and radiant heat transfer takes place from the flame to the tubes 2 and finally to the catalytic material in each tube.
[0036]
[36] Each reactor tube 2 includes a tubular heat exchanger channel 9 extending through the catalyst material for discharging the syngas from the lower portion of the tube to an outlet header 6. The discharged hot syngas provides additional heat to the catalyst material, thereby reducing heat loss through the syngas. For simplicity, only one heat exchanger channel 9 per tube is shown schematically by a curved line. The tubes may each include more than one heat exchanger channel. The heat exchanger channel typically has a coil shape.
[0037]
[37] Figure 2 is a schematic diagram of an embodiment of an ammonia cracker of an apparatus according to the present invention. Again, for simplicity, only one inlet header 25, outlet header 26, combustion air header 27, and two fuel headers 28 are shown. An ammonia feed is provided and preheated in preheater 11. The superheated feed exits the preheater and enters cracker unit 12.
[0038]
[38] Details of the cracker unit are shown in Figure 3. Apart from using unit 12 to carry out the ammonia cracking reaction rather than reforming the hydrocarbon feed, the differences from the reformer of Figure 1 are explained below.
[0039]
[39] The inlet of each reactor tube is fluidly connected to the preheater 11. In this embodiment, the reactor tube 22 is 14 meters long. A 6-meter section 33 of the reactor tube 22 extends outside the furnace 21, and an 8-meter tube section 34 extends inside the furnace 21 and is heated directly by the furnace 21. The cracker unit includes a rooftop chamber 24. No refractory material is required inside the rooftop chamber 24, and no burner heating is provided. Generally, the amount of refractory material required for the structure is reduced compared to prior art reformers. The furnace 21 is separated from the rooftop chamber by a furnace wall 32, which is a refractory lining on the interior side of the furnace 21. The reactor tube 22 extends through the furnace wall 32. The furnace wall 32 defines the tube section 33 from the section 34. In this embodiment, the combustion air header 27 and fuel header 28, as well as the burner 23 and the remainder of the fuel and combustion oxidant system, can be moved significantly below the inlet header 25 and outlet header 26. This solves a major practical problem of space consolidation within the tower equipment chamber 24.
[0040]
[40] Tubes 22 are filled with catalytic material 30 to a level above furnace wall 32. Thus, a portion of catalytic material 30 (having an upstream position with respect to the gas circulation within tubes 22) extends outside of furnace 21 and is therefore not directly heated by furnace 21. When the preheated gas feed enters the tubes in section 33 outside of furnace 21, some decomposition is initiated by contact of the superheated ammonia feed with this upstream portion of catalytic material 30. Section 33 of tube 22 extending outside of furnace 21 serves as a pre-decomposer where partially cracked gases containing ammonia, nitrogen, and hydrogen are produced, and section 34 of the tubes inside the furnace serves as a main cracker where the partially cracked gases are further cracked to yield cracked gases.
[0041]
[41] The upstream portion of the catalytic material 30, unlike the downstream portion of the catalytic material, may accommodate different heating conditions compared to the downstream portion of the catalytic material 30 that is heated directly by the furnace, and a different active catalytic material may be selected than the active catalytic material for the downstream portion of the catalytic material. For example, ruthenium may be selected for the upstream catalytic material portion because it has more catalytic activity at lower temperatures, and nickel may be selected for the downstream catalytic material portion. Alternatively, nickel may be selected for both the upstream and downstream portions, but the upstream portion may comprise a higher wt % of nickel compared to the downstream portion.
[0042]
[42] Again, each reactor tube 22 includes a tubular heat exchanger channel 31 for discharging cracked gases and heating the catalytic material 30 with the discharged hot cracked gases. For simplicity, only one heat exchanger channel 31 per tube is shown, but again, each tube may include more than one heat exchanger channel. In the embodiment of FIG. 3, the upper portion of the heat exchanger channel 31 extends through and thus heats the upstream portion of the catalytic material 30. This increases the extent of pre-cracking even outside the length of the tube directly heated by the furnace 21. The conversion rate of pre-cracking is improved compared to prior art adiabatic crackers. The shape of the heat exchanger channel 31 can be optimized for each section 33, 34 of the tube 22. For example, a coil or spiral shape may be selected for the portion 33 of the tube that extends outside the furnace 21 to increase heat transfer from the hot discharged cracked gases to this portion 33 of the tube, and a straight tubular channel may be selected for the portion 34 of the tube that extends inside the furnace 21.
[0043]
[43] It should be noted that although the present invention is detailed in an ammonia cracker embodiment, the present invention also encompasses the apparatus and its use for other endothermic processes, such as, for example, hydrocarbon reforming.
Claims
1. 1. An apparatus for endothermic reaction of a gas feed, comprising: a preheater (11) arranged to preheat said gas feed; at least one reactor tube (22), a furnace (21) arranged to heat said at least one reactor tube (22) by radiation and / or convection; Equipped with The at least one reactor tube (22) is at least partially filled with a catalytic material (30) configured to promote the endothermic reaction, and the at least one reactor tube (22) comprises: a pipe inlet for said preheated gas feed; a main reactor tube section (34) extending into the furnace (21) and a pre-reactor tube section (33) extending outside the furnace (21); the preliminary reaction tube section (33) is disposed between the tube inlet and the main reaction tube section (34), The apparatus wherein a portion of the catalytic material (30) extends into the pre-reactor tube section (33).
2. 2. The apparatus of claim 1, wherein the length of the pre-reactor tube section (33) is 30-80% of the total length of the reactor tube (22).
3. 3. The apparatus of claim 1, further comprising at least one heat exchanger channel (31) positioned to discharge a product gas produced by the endothermic reaction from the at least one reactor tube (22) and to transfer heat from the product gas to at least a portion of the catalytic material (30).
4. 4. The apparatus of claim 3, wherein the at least a portion of the catalytic material extending within the pre-reactor tube section (33) is an upstream portion of the catalytic material, and the at least one heat exchanger channel (31) is positioned to transfer heat from the product gas to at least a portion of the upstream portion of the catalytic material (30).
5. 5. The apparatus of claim 4, wherein the at least one heat exchanger channel (31) is positioned to transfer heat from the product gas to only a portion of the upstream portion of the catalytic material (30).
6. 6. The apparatus according to claim 1, further comprising at least one inlet header (25) connected to the tube inlet for supplying the preheated gas feed to the at least one reactor tube (22), and / or at least one outlet header (26) connected to the at least one heat exchanger channel (31) for discharging product gas produced by the endothermic reaction from the at least one heat exchanger channel (31), wherein the at least one inlet header (25) and / or the at least one outlet header (26) are attached to the apparatus above the at least one reactor tube (22).
7. 7. The apparatus of claim 1, wherein the portion of the catalytic material extending into the pre-reactor tube section (33) is an upstream portion of the catalytic material (30), and a downstream portion of the catalytic material (30) extends into the main reactor tube section (34).
8. The apparatus of claim 7, wherein the upstream portion of the catalytic material (30) has a lower catalytic activation temperature than the downstream portion of the catalytic material (30).
9. 10. Apparatus according to claim 7 or 8 when dependent on any one of claims 3 to 5, or according to claim 7 or 8 when dependent on any one of claims 3 to 5 and dependent on claim 6, wherein the at least one heat exchanger channel (31) extends through the downstream portion of the catalytic material (30) and through at least a part of the upstream portion of the catalytic material (30), the at least one heat exchanger channel (31) having a first shape in the downstream portion and a second shape in the upstream portion that is different from the first shape.
10. 9. Apparatus according to claim 7 or 8 when dependent on any one of claims 3 to 5, or according to claim 7 or 8 when dependent on any one of claims 3 to 5 and claim 6, wherein the at least one heat exchanger channel (31) is arranged to transfer heat from the product gas only to the downstream portion of the catalytic material (30).
11. 11. The apparatus according to claim 1, comprising a fuel and combustion oxidant system arranged to combust a fuel with an oxidant gas inside the furnace (21), the furnace (21) being defined by a furnace wall (32), the pre-reactor tube section (33) being defined from the main reactor tube section (34) by the furnace wall (32), and the fuel and combustion oxidant system being attached to the furnace wall (32).
12. 12. The apparatus according to any one of claims 1 to 11, wherein the furnace (21) is a top-fired furnace and the pre-reactor tube section (33) is the upper section of the at least one reactor tube (22).
13. Use of the device according to any one of claims 1 to 12 for the decomposition reaction of an ammonia feed.
14. Use of an apparatus according to any one of claims 1 to 12 for converting a hydrocarbon feed to hydrogen containing synthesis gas.