Heat exchange assembly and medium temperature shift conversion device

Abstract

This invention discloses a heat exchange assembly and a medium-term reforming device. The heat exchange assembly, used for steam reforming to produce hydrogen, has two opposing ends, including a first heat exchange section and a second heat exchange section, with at least a portion of the second heat exchange section disposed inside the first heat exchange section. The first heat exchange section has independent heat exchange channels for medium-term reformed gas and demineralized water, while the second heat exchange section has independent heat exchange channels for reformed gas and natural gas. The outlet of the reformed gas heat exchange channel and the inlet of the medium-term reformed gas heat exchange channel are located at the same end of the heat exchange assembly. This heat exchange assembly is suitable for integration with a medium-term reforming reactor, facilitating integration. The medium-term reforming device of this invention integrates the existing medium-term reforming reactor and heat exchange assembly into a single device, reducing the number of devices and thus reducing the floor space required, which is beneficial for the modular design of hydrogen production units.

Description

Technical Field

[0001] This invention belongs to the field of hydrocarbon steam reforming for hydrogen production technology, specifically relating to heat exchange components and medium-voltage conversion devices. Background Technology

[0002] In hydrogen production systems, to fully utilize the heat from the reformed gas and the shifted gas, a natural gas preheater (for heat exchange between the reformed gas and natural gas) and a demineralized water preheater (for heat exchange between the shifted gas and demineralized water) are typically installed. The reformed gas exiting the reformer first passes through the natural gas preheater, preheating the natural gas to the desulfurization temperature while simultaneously cooling the reformed gas to a temperature suitable for the shifted reaction. The reformed gas flowing out of the natural gas preheater then enters the shifted reactor for the shifted reaction. After the reaction is complete, the shifted gas is introduced into the demineralized water preheater, preheating the demineralized water while simultaneously cooling the shifted gas to a temperature suitable for subsequent cooling stages. In traditional hydrogen production process layouts, the natural gas preheater, the shifted reactor, and the demineralized water preheater are three independent devices, requiring pipelines to connect them. Independent installation of these devices results in a large footprint, hindering the modular design of the hydrogen production unit; furthermore, the long connecting pipelines lead to significant heat loss, hindering full heat utilization. Summary of the Invention

[0003] The present invention provides a heat exchange component and a medium-term conversion device. The heat exchange component is suitable for integration with the independent medium-term conversion reactor in the prior art. This not only facilitates the modular design of hydrogen production equipment, but also reduces connecting pipelines, thereby reducing heat loss in the pipelines and improving heat utilization.

[0004] In a first aspect, the present invention provides a heat exchange assembly for steam reforming to produce hydrogen. The heat exchange assembly has two opposing ends, including a first heat exchange section and a second heat exchange section, with at least a portion of the second heat exchange section disposed inside the first heat exchange section. The first heat exchange section has an independent medium-temperature gas heat exchange channel and a demineralized water heat exchange channel, and the second heat exchange section has an independent reformed gas heat exchange channel and a natural gas heat exchange channel. The outlet of the reformed gas heat exchange channel and the inlet of the medium-temperature gas heat exchange channel are located at the same end of the heat exchange assembly.

[0005] In some embodiments, a first heat exchange unit has a first inner cavity, comprising an outer portion of a first tube sheet, an outer shell, and a first heat exchange tube disposed within the first inner cavity. A second heat exchange unit has a second inner cavity, comprising an inner portion of a first tube sheet, an inner shell, and a second heat exchange tube disposed within the second inner cavity. The inner shell is located inside the outer shell, and at least a portion of the inner shell is disposed within the first inner cavity. The outer shell, the inner shell, and the outer portion of the first tube sheet define the first inner cavity, a medium-temperature gas heat exchange channel is defined by the first heat exchange tube, and a demineralized water heat exchange channel is defined by the first inner cavity. The inner shell and the inner portion of the first tube sheet define the second inner cavity, a reformed gas heat exchange channel is defined by the second heat exchange tube, and a natural gas heat exchange channel is defined by the second inner cavity.

[0006] In some embodiments, the second heat exchange unit further includes a composite pipe communicating with the second inner cavity. The composite pipe includes a natural gas inflow channel and a natural gas outflow channel, which are independent of each other. The natural gas inflow channel is configured to guide natural gas into the second inner cavity, and has an inlet and an outlet in the direction of natural gas inflow. The natural gas outflow channel is configured to guide natural gas out of the second inner cavity, and has an inlet and an outlet in the direction of natural gas outflow. The flow direction of the converted gas in the second heat exchange tube is consistent with the flow direction of the natural gas in the natural gas inflow channel, and along the flow direction of the converted gas, the outlet of the natural gas inflow channel is located downstream of the inlet of the natural gas outflow channel.

[0007] Specifically, the composite pipe includes an inlet pipe and an outlet pipe, wherein the inner cavity of the inlet pipe defines a natural gas inflow channel, and the cavity between the outlet pipe and the inlet pipe defines a natural gas outflow channel. More specifically, the inlet pipe includes a first parallel section and a connecting section communicating with the first parallel section. Along the flow direction of the converted gas, the connecting section is located downstream of the first parallel section, and the outlet of the natural gas inflow channel is located at the end of the connecting section away from the first parallel section. The outlet pipe includes a second parallel section, the first parallel section being embedded within the second parallel section, and the inlet of the natural gas outflow channel is located at the end of the second parallel section near the connecting section. In some embodiments, the lower ends of both the first and second parallel sections extend through the bottom of the inner shell, and the outlet of the natural gas outflow channel is located in the second parallel section outside the inner shell.

[0008] Optionally, the heat exchange assembly includes a second tube sheet disposed on the outer casing. The outer portion of the second tube sheet divides the first inner cavity into a first sub-cavity and a second sub-cavity. A demineralized water heat exchange channel is defined by the first sub-cavity. A first heat exchange tube is disposed in the first sub-cavity. The second sub-cavity communicates with the first heat exchange tube. The outer casing defining the second sub-cavity has a medium-temperature gas outlet. The inner portion of the second tube sheet divides the second inner cavity into a third sub-cavity and a fourth sub-cavity. A natural gas heat exchange channel is defined by the third sub-cavity. A second heat exchange tube is disposed in the third sub-cavity. The fourth sub-cavity communicates with the second heat exchange tube. The upper end of the composite tube is disposed in and communicates with the third sub-cavity. The inner casing defining the fourth sub-cavity has a conversion gas inlet.

[0009] In some embodiments, the first heat exchange tube includes a first helical tube segment, which is spirally wound around the outer periphery of the inner shell. A first inner cavity is provided with several layers of first heat exchange tubes distributed radially, each layer having the same helical direction and combined into a helical column shape. In some embodiments, the second heat exchange tube includes a second helical tube segment, which is spirally wound around the outer periphery of the composite tube. A second inner cavity is provided with several layers of second heat exchange tubes distributed radially, each layer having the same helical direction and combined into a helical column shape. Preferably, the helical directions of adjacent layers of first helical tube segments are opposite, and the helical directions of adjacent layers of second helical tube segments are opposite. In some embodiments, the outer and inner portions of the first tube sheet are independently arranged, and the outer and inner portions of the second tube sheet are also independently arranged.

[0010] In some embodiments, the first inner cavity is provided with several layers of first heat exchange tubes distributed radially. Each first heat exchange tube includes a first straight section and a first spiral section. The first straight section is formed at both ends of the first spiral section, and the first spiral section is spirally wound around the outer periphery of the inner shell. The spiral direction of each layer of the first spiral section is the same, and they are combined to form a spiral column. The second inner cavity is provided with several layers of second heat exchange tubes distributed radially. Each second heat exchange tube includes a second straight section and a second spiral section. The second straight section is formed at both ends of the second spiral section, and the second spiral section is spirally wound around the outer periphery of the composite tube. The spiral direction of each layer of the second spiral section is the same, and they are combined to form a spiral column. Specifically, the second straight section located in the innermost layer and closest to the first tube sheet is circumferentially offset from the outlet of the natural gas inflow channel, and the second straight section located in the innermost layer and furthest from the first tube sheet is circumferentially offset from the inlet of the natural gas outflow channel.

[0011] Secondly, the present invention provides a medium-term conversion device, including a housing, a core tube, a catalyst bed, and the heat exchange assembly described in the first aspect. The heat exchange assembly is disposed at the bottom of the medium-term conversion device. The catalyst bed is disposed within a cavity defined by the housing, and the catalyst bed is located above the heat exchange assembly. A first tube sheet is configured to provide support for the catalyst bed. The core tube is disposed within the catalyst bed and is used to guide the conversion gas to the catalyst bed for a medium-term reaction. The outer housing of the heat exchange assembly forms part of the housing, the second heat exchange tube of the second heat exchange section communicates with the core tube, and the first heat exchange tube of the first heat exchange section communicates with the cavity containing the catalyst bed. Optionally, the medium-term conversion device further includes a collection cylinder disposed on the upper side of the first tube sheet, and the second heat exchange tube communicates with the core tube via the collection cylinder.

[0012] Thirdly, the present invention provides a medium-term conversion device, comprising a shell, a core tube, a catalyst bed, a porous support plate, and the heat exchange assembly described in the first aspect. The heat exchange assembly is disposed at the bottom of the medium-term conversion device. The porous support plate and the catalyst bed are disposed within a cavity defined by the shell, the porous support plate being configured to provide support for the catalyst bed, and the porous support plate being located above and spaced apart from the outer portion of the first tube sheet. The core tube is disposed within the catalyst bed for guiding the conversion gas to the catalyst bed to undergo a medium-term reaction. The outer shell of the heat exchange assembly forms part of the shell, the second heat exchange tube of the second heat exchange section communicates with the core tube, and the first heat exchange tube of the first heat exchange section communicates with the cavity containing the catalyst bed.

[0013] The features and advantages of this invention include:

[0014] The heat exchange assembly provided by this invention includes a first heat exchange section and a second heat exchange section. The first heat exchange section is used for heat exchange between the medium-term shift gas and the demineralized water, while the second heat exchange section is used for heat exchange between the reformed gas and the natural gas. Since the outlet of the reformed gas heat exchange channel and the inlet of the medium-term shift gas heat exchange channel are located at the same end of the heat exchange assembly, this end is suitable for integration with the medium-term shift reactor, facilitating integration. The medium-term shift conversion device of this invention, equipped with a heat exchange assembly, integrates the existing medium-term shift reactor and heat exchanger into a single device, reducing the number of devices and thus reducing the floor space required, which is beneficial for the modular design of hydrogen production units. Furthermore, the integrated medium-term shift conversion device reduces the number of pipelines used to transport the reformed gas and the medium-term shift gas. For example, it saves the pipeline for transporting the reformed gas from the reformer to the natural gas preheater, and also saves the pipeline for transporting the medium-term shift gas from the medium-term shift reactor to the demineralized water preheater, which helps reduce heat loss in the pipelines and facilitates full utilization of heat. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of a medium-voltage conversion device according to the present invention is shown;

[0017] Figure 2 It shows Figure 1 A magnified diagram of Y in the diagram;

[0018] Figure 3 It shows Figure 2 A schematic diagram of the natural gas composite pipe in the second heat exchange section;

[0019] Figure 4 It shows along Figure 1 A schematic diagram of a medium-voltage converter cut along the AA direction;

[0020] Figure 5 A partial process diagram of a steam reforming hydrogen production system is shown.

[0021] Figure 6 A schematic diagram of another intermediate-voltage conversion device according to the present invention is shown;

[0022] Figure 7 It shows Figure 6 Schematic diagram of the second heat exchange section;

[0023] Figure 8 It shows along Figure 7 A partial schematic diagram of the second heat exchange section cut along the BB direction;

[0024] Figure 9 It shows Figure 6 A top view of the intermediate frequency converter.

[0025] Explanation of reference numerals in the attached figures:

[0026] 10 / 20 - Medium-term conversion unit, 10a - Converted gas / converted gas flow, 10b - Medium-term converted gas / medium-term converted gas flow, 10c - Steam / demineralized water, 10d - Natural gas / natural gas flow;

[0027] 11-Outer shell, 12-Core tube, 13-Porous support plate, 14-Catalyst bed, 15-Inner shell, 16-Upper cavity, 17-Collection cylinder, 18-Temperature sensor, 19-Flange cover, 21-Opening;

[0028] 100 / 200 - Heat exchange assembly, 101 - First tube sheet, 102 - Second tube sheet, 103 / 104 / 105 / 106 - Tube sheet;

[0029] 110 / 210 - First heat exchange section, 111 - Demineralized water pipe, 112 - Demineralized water inlet, 113 - Demineralized water pipe, 114 - Demineralized water outlet, 115 / 116 - Cavity, 117 - Medium-sized gas pipe, 118 - First heat exchange pipe, 119 - Medium-sized gas outlet;

[0030] 120 / 220 - Second heat exchange section, 121 - Converted gas pipe, 122 - Converted gas inlet, 125 / 126 / 127 - Cavity, 128 - Second heat exchange pipe, 129 - Baffle plate;

[0031] 140-Composite pipe, 142-Pipe body, 142a-Lower section pipe body, 142b-Middle section pipe body / Second parallel section, 142c-Upper section pipe body / Connecting section, 143-Inner pipe / First parallel section, 144-Side outlet, 145-Side inlet, 146-Natural gas inlet, 147-Natural gas outlet, 148-Natural gas pipe, 149-Natural gas pipe;

[0032] 218 - First heat exchange tube, 218a - First straight tube section, 218b - First spiral tube section;

[0033] 228 - Second heat exchange tube, 228a - Second straight tube section, 228b - Second spiral tube section;

[0034] 240 - Composite pipe, 242 - Baffle. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] To facilitate understanding of the invention, a brief description of the steam reforming hydrogen production process related to this invention will be provided first. Common gaseous hydrocarbon feedstocks suitable for steam reforming hydrogen production include natural gas, liquefied petroleum gas (LPG), and various refinery gases. In this invention, natural gas is used as an example feedstock for the steam reforming hydrogen production system. See [link to documentation]. Figure 5Natural gas 10d (feed gas) is preheated to the desulfurization temperature in a natural gas preheater before entering the desulfurization equipment for desulfurization. Water, after desalination, is heated to 180℃~190℃ steam 10c in a desalinated water preheater. The desulfurized natural gas 10d and steam 10c are mixed (i.e., feed gas mixture) and enter the reformer for reaction. In the catalyst bed, methane and steam reform to produce CO and hydrogen. The reformed gas 10a flowing out of the reformer is cooled by natural gas 10d in the natural gas preheater before entering the medium-term shift reactor. In the medium-term shift reactor, CO and steam are converted into CO2 and hydrogen. The medium-term shift gas 10b exiting the medium-term shift reactor enters the desalinated water preheater for heat exchange and cooling with desalinated water. After further purification and other processes, high-purity hydrogen can be obtained from the medium-term shift gas.

[0037] refer to Figure 1 This invention relates to a medium-term reforming device 10 equipped with heat exchange components, which is an important piece of equipment in a steam reforming hydrogen production system. In the medium-term reforming device 10, the reformed gas undergoes a medium-term reforming reaction to generate medium-term reformed gas. During the medium-term reforming reaction, CO and H2O in the reformed gas react to produce hydrogen and CO2. Compared to the reformed gas, the medium-term reformed gas has an increased hydrogen content and a decreased CO and H2O content.

[0038] See Figure 1 The intermediate-range conversion device 10 includes a housing 11, a core tube 12, a catalyst bed 14, and a heat exchange assembly 100. The housing 11 defines a cavity in which the heat exchange assembly 100 is disposed. The heat exchange assembly 100 has a first tube sheet 101 that divides the cavity defined by the housing 11 into an upper cavity 16 and a lower cavity. The catalyst bed 14 is disposed in the upper cavity 16, and the first tube sheet 101 provides support for the catalyst bed 14. The core tube 12 is disposed in the catalyst bed 14 and is used to guide the converted gas to the catalyst bed 14 for reaction. The heat exchange assembly 100 has a first heat exchange section 110 or a second heat exchange section 120. The first heat exchange section 110 is used for heat exchange between the intermediate-range gas and a first fluid, and it has an intermediate-range gas heat exchange channel for conveying the intermediate-range gas for heat exchange, and a first fluid heat exchange channel (e.g., a demineralized water heat exchange channel) for conveying the first fluid for heat exchange. The second heat exchange section 120 is used for heat exchange between the converted gas and the second fluid. It is provided with a converted gas heat exchange channel for conveying the converted gas for heat exchange, and a second fluid heat exchange channel (e.g., a natural gas heat exchange channel) for conveying the second fluid for heat exchange. The converted gas heat exchange channel of the second heat exchange section 120 is connected to the core tube 12, and the intermediate gas heat exchange channel of the first heat exchange section 110 is connected to the upper cavity 16.

[0039] In some embodiments, the heat exchange assembly 100 includes a first heat exchange section 110 and a second heat exchange section 120. The reformed gas flowing out of the reformer can directly enter the medium-term reforming unit 10. The reformed gas first passes through the second heat exchange section 120 of the medium-term reforming unit 10 to be cooled to a temperature suitable for the medium-term reforming reaction (e.g., 280°C–330°C), and then passes through the core tube 12 to reach the catalyst bed 14 for the medium-term reforming reaction to generate medium-term reformed gas. The medium-term reformed gas passes through the first heat exchange section 110 of the medium-term reforming unit 10 to be cooled to a temperature suitable for subsequent processes, and then flows out of the medium-term reforming unit 10. In the second heat exchange section 120, a second fluid is heated by the waste heat of the reformed gas; in the first heat exchange section, a first fluid is heated by the waste heat of the medium-term reformed gas. Both the first and second fluids are fluids that need to be heated in the steam reforming hydrogen production system. In some embodiments, the first fluid is demineralized water, and the second fluid is natural gas. The intermediate-term conversion device 10 of the present invention is equipped with a heat exchange assembly 100, integrating the intermediate-term conversion reactor and heat exchanger of the prior art into one device, reducing the number of devices and thus reducing the floor space, which is beneficial to the modular design of hydrogen production units. In addition, the integrated intermediate-term conversion device 10 can reduce the pipelines used to transport the converted gas and the intermediate-term gas. For example, it saves the pipeline for transporting the converted gas from the converter to the natural gas preheater, and also saves the pipeline for transporting the intermediate-term gas from the intermediate-term conversion reactor to the demineralized water preheater, which helps to reduce heat loss in the pipelines and facilitates the full utilization of heat.

[0040] In other embodiments, the heat exchange assembly 100 is provided with one of a first heat exchange section 110 and a second heat exchange section 120. For example, the heat exchange assembly 100 is provided with a second heat exchange section 120. The following description uses an example of a heat exchange assembly 100 provided with two heat exchange sections.

[0041] See also Figure 1 In some embodiments, the outer casing 11 is configured as a tube with an annular cross-section and extending longitudinally, open at the upper end and closed at the lower end. A first tube sheet 101 is disposed inside the outer casing 11 and divides the outer casing 11 into an upper chamber 16 and a lower chamber, with the catalyst bed 14 disposed in the upper chamber 16. The catalyst can be added to the upper chamber 16 through the upper opening of the outer casing 11. A flange cover 19 is also provided at the upper end of the outer casing 11, which is detachably connected to the outer casing 11 and prevents fluid in the upper chamber 16 from overflowing from the opening at the upper end of the outer casing 11. A longitudinally extending core tube 12 is disposed in the upper chamber 16 of the outer casing 11 and is coaxially arranged with the outer casing 11. A space is reserved between the upper end of the core tube 12 and the top of the outer casing 11, allowing the conversion gas in the core tube 12 to flow out from the upper end of the core tube 12 and enter the catalyst bed 14 located in the upper chamber 16. Several temperature sensors 18 are arranged longitudinally in the upper cavity 16 to monitor the temperature in the catalyst bed 14. For details, see [link to documentation]. Figure 1The upper cavity 16 is equipped with three temperature sensors 18, located in the upper, middle and lower parts of the catalyst bed 14, respectively, which can monitor the fluid temperature in these places.

[0042] In some embodiments, the lower end of the core tube 12 is provided with a collecting cylinder 17. The collecting cylinder 17 is configured as a cylindrical body with a small opening at the upper end and a large opening at the lower end, and the collecting cylinder 17 has a cavity 127. The core tube 12 is connected to the conversion gas heat exchange channel of the second heat exchange section 120 through the collecting cylinder 17. In some embodiments, see Figure 1 The first tube sheet 101 is disposed on the lower side of the collecting cylinder 17. It not only provides support for the catalyst bed 14 and an outlet for the intermediate-phase gas in the upper chamber 16, but also provides an outlet for the converted gas in the second heat exchange section 120. In some embodiments, the first tube sheet 101 is a flat plate with several through holes extending along the axial direction. The first tube sheet 101 includes an inner portion and an outer portion. The through holes on the inner portion communicate with the collecting cylinder 17, and the through holes on the outer portion communicate with the upper chamber 16. Alternatively, the inner and outer portions of the first tube sheet 101 can be composed of two separate flat plates. Keeping the position of the inner portion unchanged, the first tube sheet 101 on the outer portion can be disposed on the upper side of the collecting cylinder 17 or flush with the collecting cylinder 17. That is, the first tube sheet 101 is divided into two tube sheets, one of which is disposed on the outer side of the collecting cylinder 17 to provide support for the catalyst bed 14 and an outlet for the intermediate-phase gas in the upper chamber 16. Another tube sheet is located on the lower side of the collection cylinder 17 to provide an outlet for the converted gas in the second heat exchange section 120.

[0043] In some embodiments, the heat exchange assembly 100 has a separate housing, and the heat exchange assembly 100 is disposed in the lower cavity of the housing 11. In some embodiments, in order to save materials and simplify the design, the outer housing 11 located below the first tube sheet 101 is configured as the housing of the heat exchange assembly 100, in which case the lower cavity of the housing 11 can be regarded as part of the heat exchange assembly 100.

[0044] The heat exchange assembly 100 includes a first tube sheet 101, and an outer shell 11 and an inner shell 15 located below the first tube sheet 101. The inner shell 15 is configured as a tube with an annular cross-section and extending axially, with its lower end closed. The inner shell 15 is located inside the outer shell 11 and can be coaxially arranged with the outer shell 11. The cavity defined by the outer portion of the first tube sheet 101, the outer shell 11, and the inner shell 15 is a first inner cavity; the cavity defined by the inner portion of the first tube sheet 101 and the inner shell 15 is a second inner cavity. The upper end of the inner shell 15 is connected to the lower side of the first tube sheet 101 by welding or other means. In some embodiments, for the convenience of setting an interface (e.g., setting a conversion gas inlet 122), the lower end of the inner shell 15 protrudes from the outer shell 11.

[0045] See Figure 2 The heat exchange assembly 100 also includes a second tube sheet 102 disposed within the outer casing 11 and near its lower end. The second tube sheet 102 has a similar structure to the first tube sheet 101, but its central portion has a through hole to allow the composite tube 140 to pass through. The second tube sheet 102 is constructed as a flat plate, including an inner portion and an outer portion. The outer portion of the second tube sheet 102 divides the space (first inner cavity) defined by the outer casing 11, the inner casing 15, and the first tube sheet 101 into a cavity 115 (first sub-cavity) and a cavity 116 (second sub-cavity), wherein the cavity 115 is close to the first tube sheet 101. In some embodiments, a temperature sensor 18 is provided in the cavity 116 (see...). Figure 6 The second tube sheet 102 is used to measure the temperature of the intermediate gas in the cavity 116. The inner portion of the second tube sheet 102 divides the space (second inner cavity) defined by the inner shell 15 and the inner portion of the first tube sheet 101 into a cavity 125 (third sub-cavity) and a cavity 126 (fourth sub-cavity), wherein the cavity 125 is close to the first tube sheet 101.

[0046] The heat exchange assembly 100 includes a first heat exchange section 110 and a second heat exchange section 120. The first heat exchange section 110 includes an outer portion of a first tube sheet 101, an outer housing 11 located below the first tube sheet 101, and a first heat exchange tube 118 located within a cavity 115. In some embodiments, the first heat exchange tube 118 is configured as a straight tube, such as... Figure 2 As shown in the figure. Alternatively, the first heat exchange tube 118 may also be configured as a coil or the like. In some embodiments, the first heat exchange tube 118 contains a medium-change gas, and the inner cavity of the first heat exchange tube 118 is a medium-change gas heat exchange channel; the cavity 115 contains demineralized water, and the cavity 115 is a demineralized water heat exchange channel. The upper opening of the first heat exchange tube 118 is the inlet of the medium-change gas heat exchange channel, and the lower opening of the first heat exchange tube 118 is the outlet of the medium-change gas heat exchange channel.

[0047] In some embodiments, the first heat exchange tube 118 is configured as a straight tube, with its two ends connected to tube sheets 101 and 102 respectively and aligned with through holes in tube sheets 101 and 102, such that the inner cavity of the first heat exchange tube 118 communicates with cavities 16 and 116. A through hole (i.e., intermediate gas outlet 119) is provided on the outer shell 11 defining the cavity 116, providing an outlet for the intermediate gas to flow out. A demineralized water inlet 112 (i.e., the inlet of the demineralized water heat exchange channel) and a demineralized water outlet 114 (i.e., the outlet of the demineralized water heat exchange channel) are provided on the outer shell 11 defining the cavity 115, providing an inlet and outlet for demineralized water, respectively. In some embodiments, the demineralized water inlet 112 and the demineralized water outlet 114 are located at different longitudinal heights, and the demineralized water inlet 112 is located at the lower part of the outer shell 11. See also Figure 2Specifically, the demineralized water inlet 112 is located near the second tube sheet 102, and the demineralized water outlet 114 is located near the first tube sheet 101. This arrangement allows the flow direction of the demineralized water to be opposite to the flow direction of the medium-pressure gas, i.e., counter-current heat exchange improves heat exchange efficiency. Simultaneously, if some of the demineralized water vaporizes, the higher-positioned demineralized water outlet 114 facilitates the discharge of the vaporized demineralized water, reducing air resistance. In some embodiments, both the demineralized water inlet 112 and the demineralized water outlet 114 are located on the sidewall of the outer casing 11 and arranged radially opposite each other, which helps to increase the flow path of the demineralized water. (Continue to see...) Figure 2 The demineralized water inlet 112 is located on the side wall of the lower part of the outer shell 11, and the demineralized water outlet 114 is located on the outer shell 11 near the first tube sheet 101, and the two are located at the position furthest apart laterally (e.g., radially opposite each other).

[0048] It should be noted that the second tube sheet 102 and the cavity 116 are not essential. The second tube sheet 102 and the cavity 116 are provided to facilitate the convergence of the intermediate-phase gas flowing out of the multiple first heat exchange tubes 118, so that it can flow out uniformly from the intermediate-phase gas outlet 119 and simplify the pipeline layout. In some embodiments, the heat exchange assembly 100 does not have the second tube sheet 102 and the cavity 116 (that is, the first heat exchange section 110 does not have the outer part of the second tube sheet 102). The upper end of the first heat exchange tube 118 is connected to the first tube sheet 101, and its lower end is connected to the side wall or bottom wall of the outer casing 11. An intermediate-phase gas outlet communicating with the inner cavity of the first heat exchange tube 118 is formed on the outer casing 11.

[0049] Alternatively, the first heat exchange tube 118 contains demineralized water, and the inner cavity of the first heat exchange tube 118 serves as a demineralized water heat exchange channel; the cavity 115 contains medium-temperature gas, and the cavity 115 serves as a medium-temperature gas heat exchange channel. In this embodiment, the heat exchange assembly 100 does not have a second tube sheet 102 and a cavity 116. The upper cavity 16 communicates with the cavity 115 through a through hole in the first tube sheet 101, and a medium-temperature gas outlet is formed on the bottom or side wall of the outer shell 11. The two ends of the first heat exchange tube 118 are respectively connected to the side wall or bottom wall of the outer shell 11, and a demineralized water inlet and a demineralized water outlet communicating with the inner cavity of the first heat exchange tube 118 are formed on the outer shell 11.

[0050] The second heat exchange section 120 includes an inner portion of the first tube sheet 101, an inner shell 15, and a second heat exchange tube 128 located within the cavity 125. In some embodiments, the second heat exchange tube 128 is configured as a straight tube, such as... Figure 2As shown in the diagram. Alternatively, the second heat exchange tube 128 may also be configured as a coil or the like. In some embodiments, the second heat exchange tube 128 contains converted gas, and the inner cavity of the second heat exchange tube 128 serves as a converted gas heat exchange channel; the cavity 125 contains natural gas, and the cavity 125 serves as a natural gas heat exchange channel. The lower opening of the second heat exchange tube 128 is the inlet of the converted gas heat exchange channel, and its upper part is the outlet of the converted gas heat exchange channel. See also... Figure 2 , Figure 3 The second heat exchange tube 128 is constructed as a straight tube, with its two ends connected to tube sheets 101 and 102 respectively and aligned with the through holes of both, so that the inner cavity of the second heat exchange tube 128 communicates with cavities 127 and 126. A through hole (i.e., a conversion gas inlet 122) is provided on the inner shell 15 defining the cavity 126, which provides an inlet for the inflow of conversion gas. For example, the conversion gas inlet 122 is located on the inner shell 15 below the bottom wall of the outer shell 11. In some embodiments, the second heat exchange section 120 includes a composite tube 140, which is used to transport natural gas into the cavity 125 to absorb the heat of the conversion gas, and then guide the natural gas to the desulfurization equipment. The composite tube 140 is at least partially located within the cavity 125, and in some embodiments, the composite tube 140 is constructed as a straight tube with its axis parallel to the inner shell 15.

[0051] In some embodiments, the composite pipe 140 is configured to include an inlet pipe and an outlet pipe arranged coaxially. Natural gas to be heated enters the cavity 125 through the inlet pipe, and the heated natural gas flows out of the heat exchange assembly through the outlet pipe. Both the inlet pipe and the outlet pipe have inlets and outlets. The inlet and outlet of the inlet pipe are located at the lower and upper ends of the composite pipe 140, respectively, and the inlet and outlet of the outlet pipe are located at the middle and lower ends of the composite pipe 140, respectively. The composite pipe 140 is coaxially arranged with the inner shell 15, and extends axially through the bottom wall of the inner shell 15 and the second tube sheet 102, with its upper end connected to the first tube sheet 101. The outer wall of the composite pipe 140, the inner wall of the inner shell 15, and the second tube sheet 102 together define the cavities 125 and 126. In some embodiments, the inlet of the inflow pipe and the outlet of the outflow pipe of the composite pipe 140 are both located outside the inner housing 15 (i.e., the composite pipe 140 is partially located in the cavity 125), the outlet of the inflow pipe is located in the upper part of the cavity 125, and the inlet of the outflow pipe is located in the lower part of the cavity 125. Alternatively, in some embodiments, the inflow pipe and the outflow pipe of the composite pipe 140 are arranged side by side, and the inflow channel is defined only by the inner cavity of the inflow pipe, and the outflow channel is defined only by the inner cavity of the outflow pipe.

[0052] In some embodiments, the outflow pipe is located inside the inflow pipe, and an opening is formed in the side wall of the inflow pipe. This opening connects to the outflow pipe via a transverse pipe, through which natural gas in the cavity 125 flows into the outflow pipe. In other embodiments, such as Figure 3As shown, the inflow pipe is located inside the outflow pipe, and its upper end extends axially through the outflow pipe. The inflow pipe includes at least two outer diameter dimensions, such as... Figure 3 In the composite pipe shown, the outer diameter of the upper portion of the inflow pipe is the same as that of the outflow pipe, while the outer diameter of the lower portion of the inflow pipe is smaller than that of the outflow pipe. Alternatively, the outer diameter of the inflow pipe can also be the same.

[0053] Specifically, see Figure 3 The composite pipe 140 includes a pipe body 142 and an inner pipe 143 (first parallel section), with the inner pipe 143 located in the lower middle part of the pipe body 142. The inner pipe 143 is coaxially arranged with the pipe body 142. With the inner pipe 143 as a reference, the pipe body 142 can be divided into three sections: a lower section, a middle section, and an upper section. The lower section 142a is located below the inner pipe 143, the middle section 142b (second parallel section) is flush with the inner pipe 143 (first parallel section), and the upper section 142c (connecting section) is located above the inner pipe 143. Steps (baffles) are provided at the upper and lower ends of the inner pipe 143, separating the cavities of the lower section 142a and upper section 142c from the cavity of the middle section 142b. The lower section 142a, inner pipe 143, and upper section 142c are connected to form the inlet pipe of the composite pipe 140. The lower section 142a has an opening at its end, which serves as the inlet of the inlet pipe, i.e., the natural gas inlet 146. The upper section 142c has an opening on its side wall near the first tube sheet 101, which serves as the outlet of the inlet pipe, i.e., the side outlet 144 of the composite pipe 140. The middle section 142b is the outlet pipe, and the cavity defined between the inner wall of the middle section 142b and the outer wall of the inner pipe 142 provides a channel for the outflow of natural gas. The upper end of the middle section 142b is located at the bottom of the cavity 125, and an opening is provided on the outer wall of the middle section 142b within the cavity 125, which serves as the inlet of the outlet pipe, i.e., the side inlet 145 of the composite pipe 140. An opening is provided on the lower side wall of the middle section pipe 142b, which is the outlet of the outflow pipe, namely the natural gas outlet 147.

[0054] It should be noted that the lower section of the pipe 142a is not necessary. In some embodiments, the lower section of the pipe 142 is not provided, and the lower end of the inner pipe 143 is opened as a natural gas inlet 146. In this case, the natural gas pipe 148 can be directly connected to the lower end of the inner pipe 143.

[0055] In some embodiments, the second heat exchange section 120 includes a baffle plate 129 disposed within the cavity 125. The baffle plate 129 increases the flow path of natural gas within the cavity 125, thereby facilitating sufficient heat exchange between the natural gas and the converted gas. Specifically, the baffle plate 129 is a flat plate with several through holes, or the outer diameter of the flat plate is smaller than the inner diameter of the inner shell 15, creating a gap between the flat plate and the inner shell 15. This through hole or gap allows natural gas to pass through. Several baffle plates 129 are axially disposed within the cavity 125. In some embodiments, the baffle plate 129 includes a first baffle plate and a second baffle plate. The outer diameter of the first baffle plate is smaller than the inner diameter of the inner shell 15, and / or the through holes of the first baffle plate are located near the outer periphery. The outer diameter of the second baffle plate is equal to the inner diameter of the inner shell 15, and the through holes are located near the center. The first and second baffle plates are alternately disposed axially.

[0056] It should be noted that the second tube sheet 102 and cavity 126 are not essential. The second tube sheet 102 and cavity 126 are provided to facilitate the dispersion of the converted gas flowing out of the converted gas inlet into multiple second heat exchange tubes 128, simplifying the piping arrangement. In some embodiments, the heat exchange assembly 100 does not have the second tube sheet 102 and cavity 126 (i.e., the second heat exchange section 120 does not have the inner portion of the second tube sheet 102). The upper end of the second heat exchange tube 128 is connected to the first tube sheet 101, and its lower end is connected to the side wall or bottom wall of the inner shell 15. A converted gas inlet communicating with the inner cavity of the second heat exchange tube 128 is formed on the inner shell 15.

[0057] Alternatively, the second heat exchange tube 128 contains natural gas, and its inner cavity serves as a natural gas heat exchange channel; the cavity 125 contains converted gas, and its cavity 125 serves as a converted gas heat exchange channel. In this embodiment, the heat exchange assembly 100 does not have a second tube sheet 102 and a cavity 126. The cavity 127 communicates with the cavity 125 through a through hole in the first tube sheet 101, forming a converted gas inlet on the bottom or side wall of the inner shell 15. In some embodiments, the second heat exchange tube 128 extends axially, with its two ends connected to the top and bottom walls of the inner shell 15, respectively. Each second heat exchange tube 128 has a composite tube 140 communicating with its inner cavity. For example, the composite tube 140 extends upward to its upper end being located at the top of the inner cavity of the second heat exchange tube 128, and extends downward to its lower end protruding below the bottom wall of the inner shell 15.

[0058] In some embodiments, the heat exchange assembly 100 includes a natural gas pipe 148 connected to a natural gas inlet 146 of the composite pipe 140, and a natural gas pipe 149 connected to a natural gas outlet 147. The heat exchange assembly 100 may also include a demineralized water pipe 111 connected to a demineralized water inlet 112, and a demineralized water pipe 113 connected to a demineralized water outlet. The heat exchange assembly 100 may also include a conversion gas pipe 121 connected to a conversion gas inlet 122, and a medium-term conversion gas pipe 117 connected to a medium-term conversion gas outlet 119. The natural gas pipes 148 and 149, the demineralized water pipes 111 and 113, the conversion gas pipe 121, and the medium-term conversion gas pipe 117 provide interfaces for connecting the medium-term conversion device 10 to external pipelines, facilitating pipeline connections.

[0059] See Figure 4 Multiple heat exchange tubes 118 and 128 are distributed in the cavities 115 and 125, respectively, which facilitates heat exchange between the medium-temperature gas and the demineralized water, and between the converted gas and the natural gas. In some embodiments, the cavity 115 has several turns of first heat exchange tubes 118 spaced apart, for example, three turns. The cavity 125 has several turns of second heat exchange tubes 128 spaced apart, for example, six turns.

[0060] See also Figures 1 to 4 The converted gas flow 10a flows into the cavity 126 defined by the inner shell 15 through the converted gas pipe 121, passes through the second heat exchange pipe 128, the collection cylinder 17, and the core pipe 12 to reach the top of the upper cavity 16, where it is converted into medium-grade gas in the catalyst bed 14 within the upper cavity 16. The medium-grade gas flow 10b flows from the upper cavity 16 through the first heat exchange pipe 118 and the cavity 116, and exits from the medium-grade gas pipe 117. The natural gas flow 10d flows into the natural gas pipe 148, passes through the inlet pipe of the natural gas composite pipe 40, flows into the cavity 125 from the side outlet 144, flows from top to bottom through the baffle plate 129, and enters the outlet pipe of the natural gas composite pipe 40 from the side inlet 145, exiting from the natural gas pipe 149. The residual heat of the converted gas located in the second heat exchange pipe 128 can be transferred to the natural gas, thereby lowering the temperature of the converted gas and raising the temperature of the natural gas. Since the converted gas and natural gas flow in opposite directions, they can fully exchange heat, resulting in high heat exchange efficiency. Demineralized water 10c flows into cavity 115 through demineralized water pipe 111 and then flows out through demineralized water pipe 113. The residual heat of the medium-temperature gas located in the first heat exchange pipe 118 can be transferred to the demineralized water, thereby lowering the temperature of the medium-temperature gas and raising the temperature of the demineralized water. Since the medium-temperature gas and the demineralized water flow in opposite directions, they can fully exchange heat, which is beneficial to improving heat exchange efficiency.

[0061] It should also be noted that in some embodiments, the heat exchange assembly 100 is provided with only the first heat exchange section 110 or the second heat exchange section 120. When the heat exchange assembly 100 is provided with only the first heat exchange section 110, the core tube 12 can extend to the bottom of the outer shell 11 and form an opening in the bottom wall of the outer shell 11, which is the conversion gas inlet. When the heat exchange assembly 100 is provided with only the second heat exchange section 120, in some embodiments, only the first heat exchange tube 118 provided in the cavity 115 can be removed; in other embodiments, the outer shell 11 located on the lower side of the first tube sheet 101 can also be removed. In this case, the through hole located on the outer side of the first tube sheet 101 is the medium-voltage gas outlet.

[0062] The present invention also provides a medium-voltage converter 20, see below. Figure 6 The intermediate conversion device 20 has the same basic structure as the aforementioned intermediate conversion device 10, including a shell (i.e., outer shell 11), a core tube 12, a catalyst bed 14, and a heat exchange assembly 200. The upper end of the core tube 12 is closed and extends to the top of the upper cavity 16. The sidewall of the upper end of the core tube 12 is provided with several openings 21, through which the conversion gas in the core tube 12 can flow out and enter the catalyst bed 14. In some embodiments, the openings 21 are distributed circumferentially on the sidewall of the core tube 12, for example, the openings 21 are arranged around the sidewall to form a ring of openings 21. In some embodiments, the sidewall of the upper end of the core tube 12 is provided with multiple rings of openings 21 arranged along the extension direction of the core tube 12. In some embodiments, the outer periphery of the upper end of the core tube 12 is also provided with a filter screen 22 for preventing the catalyst from entering the core tube 12 through the openings 21, and the conversion gas enters the catalyst bed 14 through the filter screen.

[0063] See also Figure 6 The heat exchange assembly 200 includes a first heat exchange section 210 and a second heat exchange section 220, and its basic structure is basically the same as that of the heat exchange assembly 100. The inner and outer portions of the first tube sheet 101 of the heat exchange assembly 200 are composed of two separate flat plates. Specifically, the first tube sheet 101 includes independently disposed tube sheets 103 and 105, with the outer portion being tube sheet 103 and the inner portion being tube sheet 105. Tube sheet 103 is an annular flat plate that, together with the outer shell 11 and the inner shell 15, defines a first inner cavity. It can be disposed between the outer shell 11 and the inner shell 15, i.e., located inside the outer shell 11 and outside the inner shell 15, and is fixedly connected by welding or other methods. Tube sheet 105 is a circular flat plate that, together with the inner shell 15, defines a second inner cavity. Tube sheet 105 can be disposed inside or at the end of the inner shell 15 and is fixedly connected by welding or other methods.

[0064] The inner and outer portions of the second tube sheet 102 of the heat exchange assembly 200 are also composed of two separate flat plates. Specifically, the second tube sheet 102 includes independently disposed tube sheets 104 and 106, with tube sheet 104 being the outer portion and tube sheet 106 being the inner portion. Tube sheet 104 is an annular flat plate disposed between the outer shell 11 and the inner shell 15, dividing the first inner cavity into cavity 115 (first sub-cavity) and cavity 116 (second sub-cavity), wherein cavity 115 is close to tube sheet 103. Tube sheet 106 is a circular flat plate disposed inside the inner shell 15, dividing the second inner cavity into cavity 125 (third sub-cavity) and cavity 126 (fourth sub-cavity), wherein cavity 125 is close to tube sheet 105.

[0065] Independent tube sheets 103 and 105, as well as tube sheets 104 and 106, allow the inner and outer tube sheets to bear forces independently, avoiding interference from mutual forces, thus increasing safety and reducing the overall structural manufacturing difficulty. Furthermore, the heights of the first and second inner cavities, especially cavities 115 and 125, can be more flexibly adjusted according to heat exchange requirements to achieve a more ideal heat exchange effect. See also Figure 6 Tube sheet 105 is located above the inner side of tube sheet 103, tube sheet 106 is located below the inner side of tube sheet 104, and the height of cavity 125 is greater than the height of cavity 115.

[0066] The first heat exchange section 210 includes a first heat exchange tube 218 disposed in the first inner cavity. Both ends of the first heat exchange tube 218 are connected to tube sheets 103 and 104, respectively, and aligned with their through holes. The second heat exchange section 220 includes a second heat exchange tube 228 disposed in the second inner cavity. Both ends of the second heat exchange tube 228 are connected to tube sheets 105 and 106, respectively, and aligned with their through holes. The heat exchange tubes 218 and 228 are configured as coils. The coil configuration effectively increases the length of the heat exchange tubes 218 and 228, which is beneficial for sufficient heat exchange. The first heat exchange tube 218 and the second heat exchange tube 228 may have the same structure; the following description uses the first heat exchange tube 218 as an example. The first heat exchange tube 218 is configured as a coil, such as a serpentine, U-shaped, annular, or spiral shape. In some embodiments, the first heat exchange tube 218 is configured as a spiral coil, including a spiral tube segment 218b. The spiral tube segment 218b is spirally wound around the outer periphery of the inner shell 15, and can be wound one or several times. The first heat exchange tube 218 has a centerline, and the first heat exchange tube 218 extends along the centerline. Preferably, the centerline of the spiral tube segment 218b is also located in the same cylindrical surface, that is, each spiral tube segment 218b is integrally cylindrical. In some embodiments, the first heat exchange tube 218 further includes first straight tube segments 218a located at both ends of the spiral tube segment 218b, which facilitates the fixed connection of the first heat exchange tube 218 to the tube sheets 103 and 104, and alignment with the through holes of the tube sheets 103 and 104. The intermediate gas is located in the first heat exchange tube 218, and the demineralized water is located in the cavity 115. The temperature difference between the intermediate gas and the demineralized water is large, so thermal stress is easily generated between the first heat exchange tube 218 and the outer shell 11. However, the first heat exchange tube 218 is provided with a spiral tube section 218b, which is an elastic body (its mechanical properties are similar to those of a helical spring). The spiral tube section 218b of the first heat exchange tube 218 can absorb the temperature difference stress and avoid transmitting the temperature difference stress to the tube sheets 103 and 104, thereby enhancing the structural stability of the heat exchange assembly 200, especially with multiple first heat exchange tubes 218. In addition, the spiral tube section 218b of the first heat exchange tube 218 extends longitudinally in the cavity 115, which can increase the heat exchange surface area of ​​the first heat exchange tube 218 and enhance the heat exchange effect.

[0067] See also Figure 6The cavity 115 contains one layer or multiple layers of first heat exchange tubes 218 arranged radially. The first heat exchange tubes 218 can be arranged in one or more loops, which can be concentrically arranged. Each layer has multiple first heat exchange tubes 218, which are distributed in parallel along the circumference of the cavity 115. The multiple helical segments in each layer have the same helical direction and are combined to form a helical column. The centerlines of the multiple first heat exchange tubes 218 in the same layer can lie within the same cylindrical surface, for example, within the same circular cylindrical surface. For example, the cavity 115 has three layers of spaced-apart first heat exchange tubes 218, with the centerlines of the first heat exchange tubes 218 located on three nested cylindrical surfaces, the radii of which increase sequentially from the inside to the outside. In some embodiments, to ensure heat exchange efficiency, the lengths of the helical segments 218b of the first heat exchange tubes 218 in the same layer are equal. Furthermore, the number of layers of the first heat exchange tubes 218 can be rationally set according to heat exchange requirements, the size of the cavity 115, and the diameter of the heat exchange tubes to achieve optimal heat exchange effect. In some embodiments, when multiple layers of first heat exchange tubes 218 are provided, the spiral direction of each layer can be different. Preferably, the spiral directions of adjacent layers of first heat exchange tubes 218 are opposite; for example, one layer has a clockwise spiral direction, and another layer has a counterclockwise spiral direction. The medium (e.g., demineralized water) in the cavity 115 flows through the gaps between the first heat exchange tubes 218 and exchanges heat with the medium-sized gas in the first heat exchange tubes 218. When multiple layers of first heat exchange tubes 218 are provided, the gaps formed by adjacent layers are staggered due to the different spiral directions, which not only increases the flow path of the demineralized water but also reduces the laminar flow effect of the demineralized water, allowing the medium-sized gas and demineralized water to exchange heat fully.

[0068] The second heat exchange tube 228 includes a second straight tube segment 228a and a second spiral tube segment 228b, the second spiral tube segment 228b being spirally wound around the outer periphery of the composite tube 240. In some embodiments, the second inner cavity is provided with several layers of second heat exchange tubes 228 distributed radially, such as one layer, four layers, etc., and the multiple second spiral tube segments 228b in each layer have the same spiral direction and are combined to form a spiral column shape. See also Figure 7 In some embodiments, the cavity 125 of the second heat exchange section 220 is provided with two layers of spaced-apart second heat exchange tubes 228. The centerlines of the second heat exchange tubes 228 are located on two cylindrical surfaces, such as circular surfaces, with the radii of the two cylinders increasing from the inside to the outside and having different spiral directions. Compared with the baffle 129 provided in the second heat exchange section 120, the second spiral tube section 228b of the second heat exchange section 220 can form a structure with alternating spiral directions, which can avoid the formation of flow dead zones, enhance heat transfer, and simplify the overall structure.

[0069] See also Figure 7The second heat exchange section 220 includes a composite pipe 240, the upper end of which extends to the upper part of the cavity 125, and the lower end extends out of the bottom of the inner shell 15. The composite pipe 240 includes a pipe body 142 and an inner pipe 143, with the inner pipe 143 located in the lower middle part of the pipe body 142. A baffle 242 is provided inside the pipe body 142, dividing the pipe body 142 into a second parallel section 142b and a connecting section 142c. The baffle 242 is fixed to the inner wall of the pipe body 142, and has an opening in its middle. The upper end of the inner pipe 143 is connected to the baffle 242, and the inner cavity of the inner pipe 143 communicates with the opening, so that the inner pipe 143 communicates with the connecting section 142c. The upper part of the connecting section 142c can be fixedly connected to the lower side of the tube sheet 104. The side wall of the upper end of the connecting section 142c is provided with a plurality of side outlets 144 communicating with the cavity 125. The side outlets 144 are distributed circumferentially along the connecting section 142c. Optionally, multiple turns of side outlets 144 distributed axially along the composite pipe 240 are provided on the side wall of the connecting section 142c. The upper part of the second parallel section 142b is located at the bottom of the cavity 125. The side wall of the upper end of the second parallel section 142b is provided with a plurality of side inlets 145 communicating with the cavity 125. The side outlets 144 are distributed circumferentially along the connecting section 142c, and can be provided in one or more turns. In some embodiments, the inner tube 143 extends out of the composite pipe 240. The extended inner tube 143 can be regarded as a natural gas pipe 148, which facilitates pipeline connection.

[0070] In some embodiments, the second heat exchange tube 228 is staggered from the side outlet 144 and side inlet 145 to prevent the second heat exchange tube 228 from blocking the side outlet 144 and side inlet 145, thus affecting the flow of natural gas out or into the composite pipe 240. The second heat exchange tube 228 is arranged in one or more turns around the composite pipe 240, with the turn of the second heat exchange tube 228 adjacent to the composite pipe 240 arranged to be staggered from the side outlet 144. See also Figure 8 The side outlets 144 are distributed around the body 142 of the composite tube 240. The second straight tube segment 228a of the second heat exchange tube 228, near the tube sheet 103, is located between two adjacent side outlets 144; for example, one or more second straight tube segments 228a may be arranged between two side outlets 144. In some embodiments, the number of side outlets 144 is equal to the number of adjacent second heat exchange tubes 228, i.e., one second straight tube segment 228a is arranged between each pair of adjacent side outlets 144. Similarly, the side inlets 145 are distributed around the body 142 of the composite tube 240, and the second straight tube segment 228a of the second heat exchange tube 228, away from the tube sheet 103, is located between two adjacent side inlets 145.

[0071] In some embodiments, see Figure 9The intermediate gas pipe 117, the conversion gas pipe 121, the demineralized water pipe 111, and the demineralized water pipe 113 are located in four circumferential directions of the heat exchange assembly 200. In some embodiments, the intermediate gas pipe 117 and the conversion gas pipe 121 extend in the same direction and are located on both sides of the heat exchange assembly 200. The demineralized water pipes 111 and 113 extend in the same direction and are located on both sides of the heat exchange assembly 200, specifically, they are arranged opposite each other radially along the heat exchange assembly 200. For ease of pipe arrangement, the angle between the conversion gas pipe 121 and the demineralized water pipe 111 is 90°. In some embodiments, at least a portion of the natural gas pipe 148 extends parallel to the natural gas pipe 149, wherein the natural gas pipe 149 is parallel to the conversion gas pipe 121.

[0072] In some embodiments, see Figure 6 The heat exchange assembly 200 may further include a porous support plate 13 disposed on the upper side of the tube sheet 103. The porous support plate 13 is a flat plate and is disposed parallel to the tube sheet 103. The porous support plate 13 is used to support the catalyst bed 14 and has a plurality of through holes running vertically through it. A cavity 24 is formed between the porous support plate 13 and the tube sheet 103. The intermediate gas located in the catalyst bed enters the cavity 24 through the through holes of the porous support plate 13 and then flows into the heat exchange tubes 218 through the through holes of the tube sheet 103. The intermediate gas is buffered in the cavity 24, which can both equalize the pressure and reduce the temperature difference of the intermediate gas before entering each heat exchange tube 218, so that the intermediate gas can be evenly distributed to each heat exchange tube 218, which is conducive to the full heat exchange between the intermediate gas and the demineralized water. In some embodiments, a filter screen may be disposed on the upper side of the porous support plate 13 to prevent the catalyst from entering the cavity 24 through the through holes of the porous support plate 13.

[0073] The heat exchange components 100 and 200 of the present invention are provided with a first heat exchange section 110 and a second heat exchange section 120. The first heat exchange section 110 is used for heat exchange between the medium-term shift gas and the demineralized water, and the second heat exchange section 120 is used for heat exchange between the converted gas and the natural gas. The medium-term shift gas can flow in from the upper end of the first heat exchange tubes 118 and 218, and the converted gas can flow out from the upper end of the second heat exchange tubes 128 and 228. That is, the outlet of the converted gas heat exchange channel and the inlet of the medium-term shift gas heat exchange channel are located at the same end of the heat exchange components 100 and 200. This end is suitable for integration with the medium-term shift reactor for easy integration.

[0074] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content of the application documents without departing from the spirit and scope of the present invention.

Claims

1. A heat exchange assembly for steam reforming to produce hydrogen, characterized in that, The heat exchange assembly has two opposing ends, and the heat exchange assembly includes: A first heat exchange section, comprising an independent intermediate gas heat exchange channel and a demineralized water heat exchange channel; and A second heat exchange section is provided inside the first heat exchange section, and the second heat exchange section has a conversion gas heat exchange channel and a natural gas heat exchange channel that are independent of each other. The outlet of the conversion gas heat exchange channel and the inlet of the medium-voltage gas heat exchange channel are located at the same end of the heat exchange assembly, which is the end near the cavity containing the catalyst in the medium-voltage conversion device.

2. The heat exchange assembly according to claim 1, characterized in that, The first heat exchange section has a first inner cavity. The first heat exchange section includes an outer portion of a first tube sheet, an outer shell, and a first heat exchange tube, which is disposed in the first inner cavity. The second heat exchange section has a second inner cavity. The second heat exchange section includes an inner portion of a first tube sheet, an inner shell, and a second heat exchange tube, which is disposed in the second inner cavity. Wherein, the inner shell is located inside the outer shell, and at least a portion of the inner shell is disposed in the first inner cavity; the outer shell, the inner shell, and the outer portion of the first tube sheet define the first inner cavity, the medium-temperature gas heat exchange channel is defined by the first heat exchange tube, and the demineralized water heat exchange channel is defined by the first inner cavity; the inner shell and the inner portion of the first tube sheet define the second inner cavity, the converted gas heat exchange channel is defined by the second heat exchange tube, and the natural gas heat exchange channel is defined by the second inner cavity.

3. A heat exchange assembly for steam reforming to produce hydrogen, characterized in that, The heat exchange assembly has two opposing ends, and the heat exchange assembly includes: A first heat exchange section, comprising independent heat exchange channels for medium-temperature gas and demineralized water, and a first inner cavity, including an outer portion of a first tube sheet, an outer shell, and a first heat exchange tube disposed within the first inner cavity; and The second heat exchange section is disposed inside the first heat exchange section. The second heat exchange section has independent heat exchange channels for converted gas and natural gas. The second heat exchange section has a second inner cavity. The second heat exchange section includes an inner portion of the first tube sheet, an inner shell, and a second heat exchange tube, which is disposed in the second inner cavity. Wherein, the inner shell is located inside the outer shell, and at least a portion of the inner shell is disposed in the first inner cavity; the outer shell, the inner shell, and the outer portion of the first tube sheet define the first inner cavity; the medium-temperature gas heat exchange channel is defined by the first heat exchange tube, and the demineralized water heat exchange channel is defined by the first inner cavity; the inner shell and the inner portion of the first tube sheet define the second inner cavity; the converted gas heat exchange channel is defined by the second heat exchange tube, and the natural gas heat exchange channel is defined by the second inner cavity; The outlet of the converted gas heat exchange channel and the inlet of the intermediate gas heat exchange channel are located at the same end of the heat exchange assembly. The second heat exchange section further includes a composite tube, which is in communication with the second inner cavity; The composite pipe includes independent natural gas inflow channels and natural gas outflow channels; The natural gas inflow channel is configured to guide natural gas into the second inner cavity, and the natural gas inflow channel has an inlet in the direction of natural gas inflow and an outlet in the direction of natural gas inflow. The natural gas outflow channel is configured to guide natural gas out of the second inner cavity, and the natural gas outflow channel has an inlet in the direction of natural gas outflow and an outlet in the direction of natural gas outflow. The flow direction of the converted gas in the second heat exchange tube is consistent with the flow direction of the natural gas in the natural gas inflow channel, and the outlet of the natural gas inflow channel is located downstream of the inlet of the natural gas outflow channel along the flow direction of the converted gas.

4. The heat exchange assembly according to claim 3, characterized in that, The composite pipe includes an inlet pipe and an outlet pipe, wherein the inner cavity of the inlet pipe defines the natural gas inlet passage, and the cavity between the outlet pipe and the inlet pipe defines the natural gas outlet passage; The inflow pipe includes a first parallel section and a connecting section connected to the first parallel section. Along the flow direction of the converted gas, the connecting section is located downstream of the first parallel section, and the outlet of the natural gas inflow channel is located at the end of the connecting section away from the first parallel section. The outflow pipe includes a second parallel section, the first parallel section is embedded in the second parallel section, and the inlet of the natural gas outflow channel is located at one end of the second parallel section near the connecting section.

5. The heat exchange assembly according to any one of claims 3 and 4, characterized in that, The heat exchange assembly includes a second tube sheet disposed in the outer casing; The outer portion of the second tube sheet divides the first inner cavity into a first sub-cavity and a second sub-cavity. The demineralized water heat exchange channel is defined by the first sub-cavity. The first heat exchange tube is disposed in the first sub-cavity. The second sub-cavity is connected to the first heat exchange tube. The outer shell defining the second sub-cavity is provided with a medium-temperature gas outlet. The inner portion of the second tube sheet divides the second inner cavity into a third sub-cavity and a fourth sub-cavity. The natural gas heat exchange channel is defined by the third sub-cavity. The second heat exchange tube is disposed in the third sub-cavity. The fourth sub-cavity is connected to the second heat exchange tube. The upper end of the composite tube is disposed in the third sub-cavity and is connected to the third sub-cavity. The inner shell defining the fourth sub-cavity is provided with a conversion gas inlet.

6. The heat exchange assembly according to claim 5, characterized in that, The first heat exchange tube includes a first spiral tube segment, which is spirally wound around the outer periphery of the inner shell; the first inner cavity is provided with several layers of the first heat exchange tube distributed radially, and the spiral direction of the first spiral tube segment in each layer is the same and they are combined into a spiral column shape. The second heat exchange tube includes a second spiral tube segment, which is spirally wound around the outer periphery of the composite tube; the second inner cavity is provided with several layers of the second heat exchange tube distributed radially, and the spiral direction of the second spiral tube segment in each layer is the same and they are combined into a spiral column shape.

7. The heat exchange assembly according to claim 6, characterized in that, The first spiral tube segments of two adjacent layers have opposite spiral directions, and the second spiral tube segments of two adjacent layers have opposite spiral directions.

8. The heat exchange assembly according to claim 7, characterized in that, The outer and inner portions of the first tube sheet are set independently, and the outer and inner portions of the second tube sheet are set independently.

9. The heat exchange assembly according to claim 8, characterized in that, The first inner cavity is provided with several layers of the first heat exchange tubes distributed radially. The first heat exchange tube includes a first straight section and a first spiral section. The first straight section is formed at both ends of the first spiral section. The first spiral section is spirally coiled around the outer periphery of the inner shell. The spiral direction of each layer of the first spiral section is the same and they are combined into a spiral column. The second inner cavity is provided with several layers of the second heat exchange tubes distributed radially. The second heat exchange tube includes a second straight section and a second spiral section. The second straight section is formed at both ends of the second spiral section. The second spiral section is spirally coiled around the outer periphery of the composite tube. The spiral direction of each layer of the second spiral section is the same and they are combined into a spiral column shape. The second straight segment located in the innermost layer and close to the first tube sheet is staggered circumferentially from the outlet of the natural gas inflow channel, and the second straight segment located in the innermost layer and far from the first tube sheet is staggered circumferentially from the inlet of the natural gas outflow channel.

10. A medium-voltage converter, characterized in that, Includes a shell, a core tube, a catalyst bed, and a heat exchange assembly as described in any one of claims 2 to 9; The heat exchange assembly is disposed at the bottom of the intermediate-voltage conversion device; The catalyst bed is disposed within the cavity defined by the housing and is located above the heat exchange assembly, with the outer portion of the first tube sheet configured to provide support for the catalyst bed. The core tube is disposed in the catalyst bed and is used to guide the conversion gas to the catalyst bed to undergo a medium-scale reaction; The outer shell of the heat exchange assembly forms part of the housing, the second heat exchange tube of the second heat exchange section is connected to the core tube, and the first heat exchange tube of the first heat exchange section is connected to the cavity where the catalyst bed is located.

11. A medium-voltage converter, characterized in that, It includes a shell, a core tube, a catalyst bed, a porous support plate, and the heat exchange assembly according to any one of claims 2 to 9; The heat exchange assembly is disposed at the bottom of the intermediate-voltage conversion device; The porous support plate and the catalyst bed are disposed within the cavity defined by the housing. The porous support plate is configured to provide support for the catalyst bed. The porous support plate is located above the outer portion of the first tube sheet and is spaced apart from the upper portion of the first tube sheet. The core tube is disposed in the catalyst bed and is used to guide the conversion gas to the catalyst bed to undergo a medium-scale reaction; The outer shell of the heat exchange assembly forms part of the housing, the second heat exchange tube of the second heat exchange section is connected to the core tube, and the first heat exchange tube of the first heat exchange section is connected to the cavity where the catalyst bed is located.

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