An electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas

Abstract

The present invention discloses an electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas, comprising a reforming furnace body, a metal heating wire is arranged at the upper position of the inner cavity of the reforming furnace body, a centralizing box is mounted on the outer ring of the metal heating wire, a through opening is opened at the top of the centralizing box, and a nozzle is installed in the inner cavity of the through opening. The electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas, through the design of the centralizing box and the nozzle, when the steam and natural gas mixed gas is input, the mixed gas is sprayed in the form of a jet and directly contacts the metal heating wire, and the entry path of the mixed gas and the state of the mixed gas with the metal heating wire are redesigned, which effectively solves the problem of low heat utilization rate and heating efficiency of the mixed gas in the prior art that the mixed gas is directly poured into the reforming furnace.

Description

Technical Field

[0001] The invention relates to the technical field of reforming hydrogen production, and in particular to an electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas. Background Art

[0002] Natural gas steam reforming is a common method of industrial hydrogen production, which is widely used in the preparation of hydrogenation gas in oil refineries and the preparation of bulk chemical raw materials such as methanol, synthetic ammonia, ethylene glycol, butyl alcohol and octanol. The reaction in the reforming furnace is the core processing step of reforming hydrogen production. Usually, a mixture of natural gas and steam is preheated and enters the reforming furnace, where it undergoes a strong endothermic catalytic reaction with the catalyst to produce hydrogen, carbon monoxide and carbon dioxide.

[0003] The reformer plays a vital role in the process of hydrogen production by steam reforming of natural gas. There are many technical solutions for the current reformer, such as the existing technology:

[0004] CN217535472U, a high-pressure three-phase electric heating natural gas steam reforming furnace, the technical solution adopts an upper and lower multi-layer electric heating structure to heat the steam and natural gas flowing through the heating structure, not to mention that the upper and lower multi-layer electric heating structure has relatively large energy consumption, the steam and natural gas flowing through the heating structure area are in contact with the heating structure for a very short time, the heat of the heating structure is mainly used to heat the reforming furnace, and then the high temperature of the entire reforming furnace is used to heat the steam and natural gas, the energy loss is relatively large, and the heat utilization rate of the steam and natural gas when heating is low; similar to the above technical solution, there is another prior art: CN115196595A, a natural gas to hydrogen-rich synthesis gas electric heating steam reforming furnace, also has the same problems and defects;

[0005] CN116239084A, an electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas. Although this technical solution still heats the input steam and natural gas by heating the inner cavity of the reforming furnace, in order to save energy consumption and improve heat utilization, the excess heat is output and transferred to preheat the input steam and natural gas. This can make up for the defects and problems in the technical solution of multi-stage and multi-layer heating structure to a certain extent. However, this technical solution still has defects. That is, in the process of heat transfer, although a thermal insulation structure is used to reduce heat loss as much as possible, as the transfer path increases, heat loss is inevitable. It is very likely that the heat transferred to the input steam and natural gas position is less than the heat carried by the steam and natural gas themselves. That is, after a large amount of heat in the reforming furnace is absorbed, the heat that can be transferred and transported is relatively low, resulting in the problem of heat absorption.

[0006] Therefore, we propose a reforming furnace, which is mainly used for steam and natural gas reforming to produce hydrogen, in order to solve the above technical problems. Summary of the invention

[0007] The object of the present invention is to provide an electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A natural gas to hydrogen-rich synthesis gas electric steam reforming furnace comprises a reforming furnace body, wherein a metal heating wire is arranged at the upper position of the inner cavity of the reforming furnace body, a centralizing box is sleeved on the outer ring of the metal heating wire, a through opening is opened on the top of the centralizing box, and a nozzle is installed in the inner cavity of the through opening.

[0010] Preferably, the bottom nozzle of the nozzle pipe is located directly above the metal heating wire, and an input pipe is butt-connected to the top of the nozzle pipe.

[0011] Preferably, the inner cavity of the reforming furnace body is divided into two upper and lower cavities by a central box, and an output pipe is installed at the bottom of the reforming furnace body.

[0012] Preferably, the inner cavity of the concentration box is spiral-shaped, and a guide plate is fixedly welded on the inner wall of the concentration box.

[0013] Preferably, the guide plates are designed to be staggered in upper and lower positions, and the guide plates are made into structured catalysts through an impregnation and attachment process.

[0014] Preferably, the guide piece is a metal piece with a certain elastic force, and one end of the guide piece is in contact with the inner wall of the concentration box in the initial state, and there is an angle of 30° between the guide piece and the concentration box.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas is designed with a centralizing box and a nozzle. When the steam and natural gas mixed gas is input, the mixed gas is sprayed in a jet shape and directly contacts the metal heating wire. The entry path of the mixed gas and the state of the mixed gas with the metal heating wire are redesigned, which effectively solves the problem of low heat utilization rate and heating efficiency of the mixed gas in the prior art of directly injecting the mixed gas into the reforming furnace.

[0017] 2. The electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas adopts the design and use of an internal spiral concentrating box. On the one hand, it is to allow the entire concentrating box to deform adaptively, that is, to adapt to the internal temperature and pressure changes of the reforming furnace and the concentrating box itself. On the other hand, it utilizes the steam and natural gas after and during the reaction to continuously heat the nozzle on its moving path, that is, to preheat the steam and natural gas entering the reforming furnace. Compared with the method of external heat transfer in the prior art, it is very easy for the transferred heat to be lower than the heat of the steam and natural gas themselves, thereby absorbing the heat of the mixed gas.

[0018] 3. The electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas has an internal spiral concentrating box that cooperates with guide plates to obtain a structured catalyst through an impregnation and attachment process. The heated mixed gas moves in a wave-like manner in the concentrating box. During the movement, it can ensure that all steam and natural gas mixed gases can contact the catalyst to react, effectively solving the problem in the prior art that steam and natural gas fill the entire reforming furnace and it is impossible to ensure that all mixed gases can contact the catalyst.

[0019] 4. In the electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas, the guide plates in the state of elastic plates are designed to be staggered up and down. When the mixed gas flows, they have a certain angle. On the one hand, the flow rate of the mixed gas can be adaptively controlled as the internal pressure changes when the mixed gas flows. On the other hand, it is mainly to control and maintain the residence time of the mixed gas between the two guide plates, that is, to further ensure that the mixed gas can contact the catalyst for subsequent reactions.

[0020] 5. In the electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas, since the concentrator box is always in a heated state, the pressure in the inner cavity and middle position of the concentrator box during the entire operation of the reforming furnace is greater than the pressure in the inner cavity of the reforming furnace body. Then, the inner cavity of the reforming furnace can be divided into two parts, that is, all steam and natural gas mixed gas, as well as the gas generated by the reaction, need to pass through the concentrator box before they can be discharged and collected. Due to the pressure difference between the inside and outside of the concentrator box, all gases are ejected from the concentrator box in a jet state, that is, flow to the output pipe, which can avoid the problem of mixed gas backflow upward. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the present invention;

[0022] Figure 2 It is a cross-sectional view of the structure of the present invention;

[0023] Figure 3 This is an exploded view of the centralized box structure of the present invention;

[0024] Figure 4 It is a cross-sectional view of the concentrated box of the present invention.

[0025] In the figure: 1. reforming furnace body; 2. metal heating wire; 3. centralizing box; 4. opening; 5. nozzle; 6. inlet pipe; 7. outlet pipe; 8. guide plate. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1:

[0028] A natural gas to hydrogen-rich synthesis gas electric steam reforming furnace, such as Figure 1 As shown, it includes a reforming furnace body 1, and the overall frame of the reforming furnace body 1 is as disclosed in the prior art CN115196595A, mainly including an outer shell, a heat-insulating layer and a pressure-bearing inner shell;

[0029] like Figure 1 , Figure 2 and Figure 3 As shown, the inner cavity of the reforming furnace body 1 is provided with a metal heating wire 2, the wires at both ends of the metal heating wire 2 are installed through the reforming furnace body 1, and are electrically connected to an external power supply and a controller, and the outer ring of the metal heating wire 2 is sheathed with a centralizing box 3;

[0030] like Figure 3 and Figure 4 As shown, the concentration box 3 is a spiral box, and a through hole 4 is opened in the middle of the top of the concentration box 3. A nozzle 5 is inserted into the inner cavity of the through hole 4. The nozzle 5 is a stepped hollow tube, and the bottom nozzle of the nozzle 5 is located directly above the metal heating wire 2.

[0031] The four sides of the concentrating box 3 are mounted on the inner wall of the reforming furnace body 1 through high temperature resistant fasteners, the top of the nozzle 5 is butt-jointed with an input pipe 6 , and the bottom of the reforming furnace body 1 is mounted with an output pipe 7 .

[0032] In this embodiment, when the device is actually used, the upper end of the input pipe 6 is connected to the steam and natural gas transmission pipelines for installation;

[0033] Then, the metal heating wire 2 is connected through the power controller, and the metal heating wire 2 is powered on to start heating, so as to preheat the entire reforming furnace body 1. In particular, an instrument needs to be installed on the reforming furnace body 1 to monitor the temperature inside the reforming furnace body 1 in real time.

[0034] When the reaction temperature is reached, the control valve on the input pipe 6 is opened to allow steam and natural gas to be quickly sprayed into the nozzle 5. The quickly sprayed mixed gas is directly sprayed out from the bottom of the nozzle 5 and hits the metal heating wire 2 in a heated state. On the one hand, the innermost cavity space of the concentration box 3 is limited, and on the other hand, the mixed gas directly hits the metal heating wire 2, so that the mixed gas can be heated quickly and accurately. The mixed gas in the high temperature state is extremely active and can be more fully contacted and heated with the metal heating wire 2 in the concentration box 3. Compared with the flow-type contact heating method in the prior art, the heat utilization rate is higher and the heating time is shorter.

[0035] The mixed gas after the heating reaction flows into the middle layer of the concentrated box 3 through the gap at the bottom of the innermost circle of the concentrated box 3, and the mixed gas after the reaction also carries a large amount of heat. It turns in the middle layer of the concentrated box 3 and directly hits the outer wall of the nozzle 5 when flowing upward. The mixed gas carrying high heat can directly heat the nozzle 5 in the middle layer of the concentrated box 3. Combined with the high temperature of the inner cavity of the concentrated box 3 and the high temperature of the inner cavity of the reforming furnace body 1, the nozzle 5 and the input pipe 6 can be heated, that is, the steam and natural gas flowing in are directly preheated in the inner cavity of the reforming furnace body 1. Compared with the existing technology, the preheating utilization rate and preheating effect are better, and there will be no cooling due to the preheating transfer, and then the problem of absorbing heat from the mixed gas of natural gas and steam will occur.

[0036] Embodiment 2:

[0037] like Figure 3 and Figure 4 As shown, a guide piece 8 is fixedly welded on the surface of the concentrating box 3, and a catalyst is impregnated and attached to the surface of the guide piece 8. For the specific impregnation and attachment process, reference may be made to the prior art CN217535472U (a high-pressure three-phase electric heating natural gas steam reforming furnace): 1. Surface pretreatment of the guide piece 8: the guide piece 8 is sequentially washed with ethanol, dilute sulfuric acid, and deionized water under ultrasonic conditions and then dried; 2. Catalyst loading: the guide piece 8 after surface pretreatment is repeatedly immersed in a Ni-γAl2O3 salt solution and dried, and finally the guide piece 8 is calcined to obtain a structured catalyst through an impregnation and attachment process.

[0038] Among them, the guide piece 8 is a metal spring sheet and is arranged alternately up and down. The guide piece 8 is designed to be inclined, and the angle between the guide piece 8 and the side wall of the concentration box 3 is at least 30°, and the initial state of one end of the guide piece 8 is in contact with the side wall of the concentration box 3.

[0039] In this embodiment, based on the embodiment 1, that is, after the heated steam and natural gas mixed gas enters the middle layer of the concentration box 3, especially after turning to a horizontal state, the flowing mixed gas directly hits the surface of the guide plate 8, and then contacts with the catalyst for reaction. The previous guide plate 8 on the movement path of the mixed gas will guide the mixed gas obliquely and hit the surface of the next guide plate 8, thereby ensuring that the mixed gas can contact with the guide plate 8, i.e., the catalyst, for more sufficient and complete reaction. At the same time, the spacing between the guide plate 8 and the side wall of the concentration box 3 can change with the change of the mixed gas and the internal pressure, that is, the flow rate of the mixed gas in the catalytic reaction process can be adaptively adjusted. On the basis that the mixed gas can contact with the catalyst, the gas residence time can be increased between the two guide plates 8 for sufficient reaction. Of course, the spiral design of the concentration box 3, combined with the use of the guide plate 8, further improves the reaction efficiency, that is, the steam and natural gas can be fully utilized, avoiding the unreacted steam and natural gas in the subsequent discharge process.

[0040] Embodiment 3:

[0041] The area between the bottom of the concentrating box 3 and the bottom of the reforming furnace body 1 is used to buffer the reaction generated gas, which is then discharged from this space through the output pipe 7 for gas collection. Since the concentrating box 3 is designed with a spiral structure, the pressure in its own inner cavity and the middle space is greater than that in the inner cavity of the reforming furnace body 1. All gases can only flow from top to bottom along the reforming furnace body 1, and there will be no upward reflux, and they move in a downward spraying state. Compared with the prior art, the mixed gases are mixed in the reforming furnace. Whether it is the gas generated by the reaction or the mixed gas of steam and natural gas, there are problems of reflux and discharge of unreacted mixed gases.

[0042] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A natural gas to hydrogen-rich synthesis gas electric steam reforming furnace, comprising a reforming furnace body (1), characterized in that: A metal heating wire (2) is arranged at the upper position of the inner cavity of the reforming furnace body (1); a centralizing box (3) is sleeved on the outer ring of the metal heating wire (2); a through opening (4) is opened at the top of the centralizing box (3); a nozzle (5) is installed in the inner cavity of the through opening (4); a guide piece (8) is fixedly welded on the inner wall of the centralizing box (3); the guide piece (8) is a metal piece with a certain elastic force, and one end of the guide piece (8) is in contact with the inner wall of the centralizing box (3) in the initial state; there is an angle of 30° between the guide piece (8) and the centralizing box (3); and the guide piece (8) is designed to be staggered in upper and lower positions.

2. The electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas according to claim 1, characterized in that: The bottom nozzle of the nozzle pipe (5) is located directly above the metal heating wire (2), and an input pipe (6) is butt-connected to the top of the nozzle pipe (5).

3. The electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas according to claim 1, characterized in that: The inner cavity of the reforming furnace body (1) is divided into two upper and lower cavities by a centralizing box (3), and an output pipe (7) is installed at the bottom of the reforming furnace body (1).

4. The electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas according to claim 1, characterized in that: The inner cavity of the concentration box (3) is spiral-shaped.

5. The electric steam reforming furnace for producing hydrogen-rich synthesis gas from natural gas according to claim 1, characterized in that: Furthermore, the guide plate (8) is manufactured into a structured catalyst through an impregnation attachment process.

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