Electric heating device

Abstract

The invention provides an electric heating device (1) comprising at least: - an electric heating oven (2) having a top (2A) and walls defining a space (3); - at least one tube (10) passing through the space (3), wherein the at least one tube (10) has an inlet (11) and an outlet (12) outside the space (3); - an electric radiant heating element (20) located in the space (3), the heating element (20) being capable of heating the at least one tube (10); wherein the heating element (20) is suspended from the top (2A) of the space (3); and wherein the top (2A) of the space (3) has a shape configured to suspend a heating element (20) at different heights.

Description

[0001] This invention relates to an electric heating device, specifically an electric heating device for performing gas conversion reactions or heating fluids at high temperatures and high heat intensity.

[0002] Various electrically heated reactors are known in the art.

[0003] For example, WO2020 / 002326A1 discloses a reactor configuration comprising at least one electrically heated furnace defining a space, wherein at least one reaction tube is placed within the furnace space. The reaction tube is heated using at least one electrically radiant heating element.

[0004] A problem associated with the aforementioned or other known electric reactors is that, in the event of premature failure or aging of the radiant heating elements, it is often necessary to shut down the furnace space or (by personnel) enter the furnace space. This can lead to prolonged interruptions of the furnace and related processes, as well as associated production disruptions. This can result in very high costs, particularly for the large-scale plants (>50MW) specifically considered in this invention, due to production losses.

[0005] Another issue is that when brittle ceramic materials are used in heating elements, the breakage of a broken heating element can potentially cause a domino effect (i.e., impacting other heating elements) when it falls onto a lower-positioned heating element. A similar effect can occur when certain metal heating elements are used, although this involves molten metal falling onto a lower-positioned heating element, potentially causing an electrical malfunction.

[0006] The purpose of this invention is to overcome or minimize one or more of the problems mentioned above or others.

[0007] Another object of the present invention is to provide an alternative electric heating device, specifically suitable for high-temperature reactions (such as above 400°C), heating fluids at high temperatures, and for large-scale (>50MW) applications (using multiple tubes).

[0008] One or more of the above or other objectives can be achieved by providing an electric heating device, which includes at least:

[0009] - An electric heating furnace having a top and walls that define a space;

[0010] - At least one pipe passing through the space, wherein the at least one pipe has an inlet and an outlet outside the space;

[0011] - An electric radiant heating element located in the space, the heating element being capable of heating the at least one tube;

[0012] The heating element is suspended from the top of the space; and

[0013] The top of the space is configured to suspend heating elements at different heights.

[0014] It has been surprisingly discovered according to the invention that, in the event of premature failure or aging of the radiant heating element used in the device according to the invention, the radiant heating element can be easily replaced without shutting down the furnace space or (by a person) entering the furnace space.

[0015] Furthermore, the device according to the invention provides precise temperature control of the pipes and the fluid flowing through them in devices designed for large-scale (>50MW) applications (where multiple pipes are used). This reduces the generation of unwanted byproducts (such as coke formation) and extends the operating time of the device.

[0016] Another advantage of the device according to the invention is that, by placing the heating element at different heights, the heating element can heat the tube along its entire length. This is especially true considering that the length of the tube is typically longer than the length of the individual heating element.

[0017] Another advantage of the present invention is that, with appropriate adjustments, the principles of the present invention can also be applied to existing devices.

[0018] Those skilled in the art will readily understand that electric heating devices can vary widely and may include several additional components. Since those skilled in the art are familiar with how to design electric heating devices, they will not be discussed in detail here.

[0019] As described above, the apparatus includes an electrically heated furnace having a top and walls that, together with the bottom, define a (furnace) space. The walls, top, and bottom of the furnace typically include refractory materials and insulation to prevent excessive heat leakage to the outside of the furnace. The electrically heated furnace may provide some non-electric heating (not as a result of an exothermic reaction), but preferably at least 50%, preferably at least 80%, and most preferably all of the heating is provided by electric heating.

[0020] As described above, the top of the furnace space in the device according to the invention has a shape configured to suspend heating elements at different heights. For this purpose, the top can have a shape that forms an angle with the vertical direction, preferably a stepped shape. According to a preferred embodiment of the device according to the invention, the top has a shape selected from the group consisting of gable, stepped, and fishtail shapes, preferably a fishtail shape. This allows the heating elements to be suspended at different heights (and to provide heat to different portions of one or more tubes). In this regard, those skilled in the art will readily understand that not all heating elements need to be suspended at different heights; in the case of, for example, multiple rows of heating elements, the heating elements in the same row will generally be suspended at the same height.

[0021] Furthermore, preferably, the heating element is removably connected to the top of the space in a manner that allows it to be replaced via the top, preferably by means of a closable opening in the top. This allows easy access to the heating element and provides the possibility of replacing it even in the event of premature failure or aging during operation of the device. In the case of replacing the heating element during furnace operation, the replacement is preferably performed in a pressure chamber to maintain the pressure in the furnace at an appropriate level (and to prevent excessive heat loss from the furnace).

[0022] The at least one tube (but usually several tubes) passing through the space can vary widely, provided that the tube has an inlet and an outlet outside the space. By way of example only, the tube does not have to be straight (though straight is preferred), but can be, for example, S-shaped or U-shaped. When using a U-shaped tube, the inlet and outlet can both be located on one side (e.g., at the top). If several tubes are present, they preferably extend substantially parallel to each other. In the case where the device is in the form of a reactor (and therefore not merely for heating), these tubes can be referred to as "reaction tubes." The tubes can be in the form of coils, i.e., spiral shapes.

[0023] There are no particular limitations on the radiant heating elements (located in the furnace space). Typically, resistance heating (utilizing the Joule effect) is used for heating these elements. Generally, the radiant heating elements are suitable for temperatures above 300°C. Preferably, they are suitable for temperatures in the range of 400°C to 1600°C. Preferably, the radiant heating elements comprise resistance heating elements based on NiCr, SiC, MoSi2, or FeCrAl.

[0024] Those skilled in the art will readily understand that electric radiant heating elements can take many different shapes, such as rods, plates, sheets, grids, and rods (e.g., ceramic) with heating wires wound around them.

[0025] Typically, the length of the heating element is less than the length of one or more tubes. Therefore, several separate heating elements are usually used to heat one or more tubes along their entire length.

[0026] According to a preferred embodiment, the device includes at least ten tubes passing through the space. Preferably, these tubes extend substantially parallel to each other.

[0027] Furthermore, it is preferable that one or more pipes extend in a substantially vertical manner. In such a vertical arrangement of these pipes, it is preferable that the fluid flowing through these pipes flows downwards. Thus, in this case, the inlet of the pipe is located at the top and the outlet is located at the bottom.

[0028] To avoid overheating of the tube, it is preferable that the radiant heating element does not come into direct contact with the tube. In other words, the heating element and the tube do not come into contact with each other, or at least are not located in the furnace space.

[0029] Although heating elements can take many forms, tubular heating elements, i.e., rod-shaped heating elements, are particularly preferred. A suitable example of a suitable tubular heating element is a commercially available silicon carbide (SiC) rod.

[0030] This tubular SiC heating element allows for a compact design of the furnace space.

[0031] On the other hand, the present invention provides a method for performing a fluid conversion reaction or heating using an electric heating device according to the present invention, wherein the method includes at least the following steps:

[0032] a) Supplying a raw material flow via the inlet of the pipe;

[0033] b) Using the heating generated by the electric radiation heating element, the raw material flow flowing through the tube is subjected to a fluid conversion reaction or heated in the space of the device, thereby obtaining one or more reaction products or a heated raw material flow;

[0034] c) Remove one or more reaction products or heated feed streams from the apparatus via the outlet of the tube.

[0035] Although not limited thereto, the method according to the invention is particularly intended for use in heating or fluid conversion reactions in large-scale applications (>50MW).

[0036] Those skilled in the art will readily understand that there are no particular limitations on the nature of this fluid conversion reaction. Non-limiting but preferred examples are SMR (steam methane reforming), steam cracking, etc.

[0037] The invention will be further described below with reference to the following non-limiting drawings. Wherein:

[0038] Figure 1 A schematic cross-sectional side view of the device according to the invention, having a fishtail gable shape, is shown;

[0039] Figure 2 schematically shown Figure 1 A front cross-sectional view of the device; and

[0040] Figure 3 A schematic cross-sectional top view of the device according to the invention is shown.

[0041] For descriptive purposes, the same reference numerals denote the same or similar parts.

[0042] exist Figure 1In the implementation plan, Figure 1 The electric heating device (generally indicated by reference numeral 1) is shown as a reactor. However, those skilled in the art will readily understand that the device can also be used to heat the fluid (only), i.e., without a reaction.

[0043] Figure 1 The reactor 1 includes: an electric heating furnace 2 having a top 2A, a bottom 2B, and a wall 2C defining a furnace space 3 therein; and a plurality of reaction tubes 10 ( Figure 1 (Only one is shown in the image) and multiple electric radiant heating elements 20.

[0044] The radiant heating element 20 is located in the space 3 and suspended from the top 2A. Because the top 2A of the space 3 has a fishtail gable shape, the heating element is suspended at different heights (although heating elements in the same row are usually suspended at the same height). The heating element 20 is removably connected to the top 2A of the furnace space 3; Figure 1 In the implementation scheme, there is a closable opening 4 in the top 2A.

[0045] like Figure 1 As shown, the reaction tube 10 passes through the space 3 and has an inlet 11 and an outlet 12 outside the space 3. Furthermore, the reaction tube 10 extends in a substantially vertical manner.

[0046] As in Figure 1 As can be further seen, the electric radiation heating element 20 is not in direct contact with the reaction tube 10.

[0047] The top 2A, bottom 2B and walls 2C of the furnace space 2 are typically made of heat-resistant structural materials and may be insulated to prevent excessive heat leakage from the interior of the furnace 2 to its exterior.

[0048] In the event of premature failure or aging of the electric radiation heating elements 20 used in the reactor 1 according to the invention, these heating elements can be easily replaced (via the closable opening 4 in the top 2A) without shutting down the reactor 1 or allowing personnel to enter the reactor 1.

[0049] If the heating element 20 is replaced during reactor operation, the replacement is preferably carried out in a pressure chamber (not shown) to maintain the pressure in the furnace space 3 at an appropriate level (and to prevent excessive heat from leaving the reactor from the furnace space 3).

[0050] As in Figure 2 As can be seen in the front view, reactor 1 includes a row of four parallel tubes 10.

[0051] As from Figure 3As can be clearly seen in the top view, all of the heating elements 20 can be easily accessed from the top 2A of the reactor 1 (which has a fishtail gable shape).

[0052] exist Figures 1 to 3 During the operation of the reactor, a fluid flow (usually gas) is supplied through the inlet 11 of the reaction tube 10. Then, using heating generated by the electric radiation heating element 20, the fluid flow through the reaction tube 10 undergoes a fluid conversion reaction in the space 3 of the reactor 1 (within the reaction tube 10) to obtain one or more reaction products.

[0053] Subsequently, one or more reaction products are removed from reactor 1 via outlet 12 of reaction tube 10.

[0054] Those skilled in the art will readily understand that many modifications can be made without departing from the scope of the invention.

Claims

1. An electric heating device, said electric heating device comprising at least: - An electric heating furnace having a top and walls defining a space; - At least one pipe passing through the space, wherein the at least one pipe has an inlet and an outlet outside the space; - An electric radiant heating element located in the space, the heating element being capable of heating the at least one tube; The heating element is suspended from the top of the space, and the heating element is not in direct contact with the at least one tube; and The top of the space is configured to suspend heating elements at different heights, wherein the top has a shape selected from a group consisting of gable, stepped, and fishtail shapes.

2. The device according to claim 1, wherein the top is fishtail shaped.

3. The apparatus of claim 1, wherein the heating element is removably connected to the top of the space in such a manner that the heating element can be replaced via the top by means of a closable opening in the top.

4. The apparatus of claim 1, wherein the apparatus comprises at least ten tubes passing through the space.

5. The apparatus of claim 1, wherein the at least one tube extends substantially vertically.

6. A method for performing a fluid conversion reaction or heating using an electric heating device according to any one of claims 1-5, wherein the method comprises at least the following steps: a) Supplying a raw material flow via the inlet of the pipe; b) Using the heating generated by the electric radiation heating element, the raw material flow flowing through the tube is subjected to a fluid conversion reaction or heated in the space of the device, thereby obtaining one or more reaction products or a heated raw material flow; c) Remove one or more reaction products or heated feed streams from the apparatus via the outlet of the tube.

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