A petrochemical electric heating furnace with uniform heating

Abstract

The utility model relates to petrochemical equipment technical field, concretely relates to a petrochemical electric heating furnace that is heated evenly, including the furnace wall that encloses furnace chamber, the inner wall of furnace wall is equipped with heat insulating lining, and the furnace chamber is equipped with multiple heat exchange pipes, and multiple heat exchange pipes are arranged in multiple rows, and the electric heating rod arranged in an array is arranged between every two adjacent rows of heat exchange pipes, and the two wiring ends of electric heating rod are worn out furnace wall outside, and electric heating rod and heat exchange pipe are parallelly distributed, and the thermocouple is arranged between every two adjacent rows of heat exchange pipes, and the control module outside furnace chamber is connected to thermocouple and electric heating rod, and control module controls the heating power of each row of electric heating rod according to the temperature signal of multiple thermocouple feedbacks, compared with prior art, multiple heat exchange pipes and multiple electric heating rods are spaced distribution, and each row of heat exchange pipe both sides has electric heating rod heat radiation, makes heat exchange pipe heat more evenly, and heat exchange pipe both sides heat more close, fully utilizes the space in the furnace, improves heat exchange efficiency.

Description

Technical Field

[0001] This utility model relates to the field of petrochemical equipment technology, specifically to a petrochemical electric furnace with uniform heating. Background Technology

[0002] The cracking furnace is the core equipment of an ethylene plant, mainly composed of a radiant section and a convection section. The convection section is the main component of the cracking furnace, and its function is to recover heat from the high-temperature flue gas to heat the cracking feedstock, boiler feedwater, and steam, thereby reducing the exhaust gas temperature and improving the thermal efficiency of the cracking furnace.

[0003] The convection section module consists of a furnace wall steel structure, furnace tubes, tube sheets, a lining, and an elbow box. The furnace wall steel structure mainly comprises two vertically opposite steel walls fixed together. The lining is laid on the inner surface of the two steel walls. The tube sheets are vertically arranged, connected to the two steel walls on both sides. Multiple tube sheets are arranged along the width of the steel walls, and each tube sheet has multiple tube holes. The furnace tubes pass through the tube holes on the tube sheets and are installed horizontally between the two steel walls. The elbow box is installed on the side of the furnace wall steel structure and contains elbows. One end of the elbow connects to the furnace tube of one convection section module, and the other end connects to the furnace tubes in other convection section modules, so that the furnace tubes in different layers of convection section modules are connected to form a complete heat exchange channel. The upper and lower layers of convection section modules are internally connected, forming a high-temperature flue gas channel from bottom to top. The high-temperature flue gas generated by the pyrolysis furnace radiation section is introduced into the high-temperature flue gas channel of the pyrolysis furnace convection section above it to exchange heat with the heat exchange channel in the pyrolysis furnace convection section, thereby heating the materials in the furnace tubes, such as pyrolysis feedstock, steam, and boiler feedwater.

[0004] The radiant combustion section produces high-temperature flue gas from fuels such as gas, coal, and gasoline, which suffers from high fuel consumption and environmental pollution. Later, resistance heating technology emerged, where spiral electric heating wires are arranged on the inner wall of the furnace. The heat generated diffuses from the inner wall into the furnace body, heating the heat exchange tubes inside. As the hot gas flows inward through layers of heat exchange, its heat gradually diminishes within the furnace, with the temperature decreasing closer to the center of the heat exchange tubes. This results in uneven heat exchange between the inner and outer heat exchange tubes. Utility Model Content

[0005] In view of the above-mentioned technical problems, the present invention provides a petrochemical electric furnace with uniform heating.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A petrochemical electric furnace with uniform heating is provided, comprising a furnace wall surrounding a furnace chamber, the inner wall of the furnace wall being provided with a heat-insulating lining, and the furnace chamber being provided with multiple heat exchange tubes, characterized in that: Multiple heat exchange tubes are arranged in multiple rows, and electric heating rods are arranged between each two adjacent rows of heat exchange tubes. The two terminals of the electric heating rods extend out of the furnace wall, and the electric heating rods are distributed side by side with the heat exchange tubes. A thermocouple is arranged between each pair of adjacent rows of heat exchange tubes. The thermocouples and electric heating rods are connected to a control module located outside the furnace chamber. The control module controls the heating power of each row of electric heating rods based on the temperature signals fed back by multiple thermocouples.

[0007] As a further optional technical solution, each row of heat exchange tubes and each row of electric heating rods are arranged along a straight or curved trajectory, and the arrangement trajectory of each row of electric heating rods is parallel to that of each row of heat exchange tubes.

[0008] As a further optional technical solution, each row of heat exchange tubes and each row of electric heating rods are arranged along a circular trajectory, with each ring of heat exchange tubes and each ring of electric heating rods arranged sequentially at intervals along a concentric circular trajectory.

[0009] As a further optional technical solution, multiple electric heating rods arranged between each pair of adjacent rows of heat exchange tubes: Each electric heating rod is a single, continuous structure; or: multiple electric heating rods are provided along the length of the heat exchange tube.

[0010] As a further optional technical solution, if the electric heating rod is a single structure, then the thermocouple is arranged near the middle of the electric heating rod; Alternatively: The electric heating rod has a segmented structure, and multiple electric heating rods at the same height of the heat exchange tube are connected to form a group of electric heating rods, with thermocouples installed on the side of each group of electric heating rods.

[0011] As a further optional technical solution, it includes multiple heat exchange modules, each heat exchange module including the furnace wall, the heat exchange tube and the electric heating rod, and the multiple heat exchange modules are stacked longitudinally or laterally.

[0012] As a further optional technical solution, in each row of heat exchange tubes, the ends of two adjacent heat exchange tubes are connected by an elbow, so that each row of heat exchange tubes is connected in series, and the ends of the first and last heat exchange tubes in each row are sealed and pass through the furnace wall.

[0013] As a further optional technical solution, the furnace wall is provided with a positioning hook to hook the elbow.

[0014] As a further optional technical solution, the electric heating rod is a graphite carbon rod.

[0015] As a further optional technical solution, the electric heating rod is of equal diameter; or: the electric heating rod is of non-equal diameter with its diameter varying in stages or gradually upwards.

[0016] As a further optional technical solution, metal fins are provided between two adjacent heat exchange tubes, so that each row of heat exchange tubes is connected to form a whole screen structure; and / or: the furnace chamber is a sealed cavity, and the furnace wall is provided with an inert gas input pipe that connects to the furnace chamber.

[0017] The beneficial effects of this utility model are: This utility model discloses a petrochemical electric furnace with uniform heating. Compared with existing technologies, it features multiple rows of heat exchange tubes and multiple rows of electric heating rods spaced apart, with electric heating rods radiating heat from both sides of each row of heat exchange tubes. This results in more uniform heating of the heat exchange tubes and closer heating on both sides, improving heat exchange efficiency. It also makes full use of the furnace space, achieving high thermal efficiency, and allows for a smaller volume while meeting the same heat exchange requirements.

[0018] Furthermore, thermocouples facilitate temperature monitoring in different zones and control the heating power of different electric heating rods, thereby achieving zoned temperature control and making the heat exchange tubes in each zone of the furnace heat up more evenly.

[0019] Furthermore, electric heating eliminates the need for air convection required by traditional combustion, allowing the furnace body to be sealed, reducing air corrosion of the furnace tubes, and even enabling the use of inert protective gas. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings. However, the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the petrochemical electric furnace in Example 1.

[0022] Figure 2 for Figure 1 A sectional view of the longitudinal section.

[0023] Figure 3 for Figure 2 A partial schematic diagram.

[0024] Figure 4 for Figure 1 A cross-sectional view of the transverse section, relative to Figure 1 The perspective has been adjusted.

[0025] Figure 5 This is a schematic diagram of the structure of the petrochemical electric furnace in Example 2.

[0026] Figure 6 for Figure 5 A sectional view of the longitudinal section.

[0027] Figure 7 for Figure 5 A cross-sectional view of the transverse section, relative to Figure 5 The perspective has been adjusted.

[0028] Figure 8 This is a schematic diagram of a modular structure for the petrochemical electric furnace in the embodiment.

[0029] Figure 9 This is a schematic diagram of a horizontally positioned petrochemical electric furnace in an embodiment.

[0030] Figure label: 1. Furnace wall; 2. Insulation lining; 3. Heat exchange tube; 4. Electric heating rod; 5. Elbow; 6. Positioning hook; 7. Flange. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] The petrochemical electric furnace of Example 1, such as Figures 1 to 7 As shown, it includes a furnace wall 1 that surrounds the furnace chamber, the inner wall of the furnace wall 1 is covered with a heat insulation lining 2, and the furnace chamber is equipped with multiple heat exchange tubes 3.

[0033] Multiple heat exchange tubes 3 are arranged in multiple rows. Between each pair of adjacent rows of heat exchange tubes 3, there are arranged electric heating rods 4. The two terminals of the electric heating rods 4 extend out of the furnace wall 1. The electric heating rods 4 are distributed side by side with the heat exchange tubes 3. The electric heating rods 4 can be made of graphite carbon rods.

[0034] like Figures 1 to 4 As shown, each row of heat exchange tubes 3 and each row of electric heating rods 4 are arranged along a straight trajectory, and the arrangement trajectory of each row of electric heating rods 4 is parallel to that of each row of heat exchange tubes 3. As for the outermost heat exchange tube 3, an electric heating rod 4 can be further installed inside the heat insulation lining 2 to heat the outermost heat exchange tube 3.

[0035] Of course, in practice, each row of heat exchange tubes 3 and each row of electric heating rods 4 can be arranged along a curved trajectory.

[0036] like Figures 5 to 7 As shown, in the petrochemical electric furnace of Embodiment 2, each row of heat exchange tubes 3 and each row of electric heating rods 4 are arranged along a circular trajectory, with each ring of heat exchange tubes 3 and each ring of electric heating rods 4 arranged in concentric circles at intervals. It can be seen that the innermost ring is a ring of electric heating rods 4, the second ring is a ring of heat exchange tubes 3, the third ring is a ring of electric heating rods 4, and so on.

[0037] In both embodiments described above, the ends of two adjacent heat exchange tubes 3 are connected via elbows 5, thus connecting each row of heat exchange tubes 3 in series. The ends of the first and last heat exchange tubes 3 in each row are sealed outside the furnace wall 1. In practical applications, the tube-side medium can flow independently in each row of heat exchange tubes 3, or the rows of heat exchange tubes 3 can be connected together. The furnace wall 1 is equipped with positioning hooks 6 to engage the elbows, improving structural stability.

[0038] In this petrochemical electric furnace, a thermocouple (not shown in the figure, which is a commonly used temperature measuring element in temperature measuring instruments) is arranged between each two adjacent rows of heat exchange tubes 3. It directly measures the temperature and converts the temperature signal into a thermoelectric potential signal. The thermocouples and electric heating rods 4 are connected to a control module located outside the furnace chamber through cables. The control module controls the heating power of each row of electric heating rods 4 according to the temperature signals fed back by multiple thermocouples.

[0039] In the two embodiments above, each electric heating rod 4 is a single, continuous structure. Each electric heating rod 4 extends from the top and bottom of the furnace wall 1, sealed at both ends. In practice, the electric heating rods 4 in the same row are connected in series / parallel, arranged in rows. The control module controls the heating power of each row of electric heating rods 4 by changing the current / voltage value. Thermocouples are preferably arranged near the middle of the heat exchange tube 3. When the temperature is below a preset range, the heating power of the corresponding row of electric heating rods 4 is increased; when the temperature is above the preset range, the heating power of the corresponding row of electric heating rods 4 is decreased, thereby achieving temperature uniformity throughout the electric furnace. Here, temperature control refers to controlling the temperature within a range, not a specific numerical value.

[0040] Metal fins 7 are provided between two adjacent heat exchange tubes 3, so that each row of heat exchange tubes 3 is connected into a whole screen structure, reducing heat flow between each row of heat exchange tubes 3 and making it easier to control the temperature field in different areas.

[0041] In practice, this can be modified as follows: Within each row of electric heating rods 4, along the length of the heat exchange tube 3, each electric heating rod 4 is segmented. Multiple segments of electric heating rods 4 at the same height of the heat exchange tube 3 are interconnected to form a heating group. Thus, adjacent rows of heat exchange tubes 3 are surrounded by multiple heating groups along the length of the heat exchange tube 3. Thermocouples are installed on the side of each heating group. The control module controls the heating power of each heating group (by adjusting the current / voltage). The segmented structure is more suitable for scenarios where the heat exchange tube 3 is relatively long.

[0042] In practice, it is possible to have the electric heating rod 4 with a uniform diameter structure, so that the heat output of the same electric heating rod 4 is basically the same, and the heat output of the vertically arranged electric heating rod 4 is similar throughout the longitudinal direction.

[0043] Considering the property that hot air always rises and heat accumulates upwards, the electric heating rod 4 has a non-uniform diameter structure with a graded or gradually changing diameter upwards. Under the same current / voltage, the electric heating rod 4 generates less heat upwards by varying its thickness, resulting in a greater degree of heating at the bottom and a smaller degree of heating at the top, but with the superposition of heat accumulation, achieving a more uniform heating effect from top to bottom.

[0044] In this embodiment, the furnace chamber is a sealed chamber, and the furnace wall 1 is provided with an inert gas input pipe that connects to the furnace chamber. Inert gas is introduced to reduce the corrosion of the heat exchange tube 3 surface by air.

[0045] like Figure 1 and Figure 5 The image shows a vertically arranged petrochemical electric heating furnace with a single, integral furnace wall. The heat exchange tubes are vertically arranged, extending from the bottom to the top of the furnace chamber, and the electric heating rods run vertically through the furnace wall. In practice, it could be modified as follows: Figure 9 The horizontally arranged petrochemical electric heating furnace shown has its furnace walls arranged horizontally, heat exchange tubes arranged on the left and right sides of the furnace chamber, and electric heating rods penetrating the furnace walls on the left and right sides.

[0046] In practice, the electric heating furnace can also have a modular structure. The entire electric heating furnace includes multiple heat exchange modules 8, and each heat exchange module 8 includes the furnace wall, the heat exchange tube, and the electric heating rod, such as... Figure 8 As shown, multiple heat exchange modules 8 are arranged horizontally stacked, and the furnace walls of different heat exchange modules 8 are sealed and fixed together by flanges. Of course, in practice, multiple heat exchange modules can be arranged vertically stacked. The heat exchange tubes in different heat exchange modules can extend out of the corresponding furnace walls and be connected to each other through pipes. The electric heating rods of different heat exchange modules can be independent of each other, or they can be connected in series / parallel to each other for easy centralized control.

[0047] In the description of this utility model, it is obvious that the described embodiments are only a part of the embodiments of this utility model, and not all of them. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0048] Therefore, the above detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0049] In the description of this utility model, it should be noted that the terms "middle," "upper," "lower," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0050] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

Claims

1. A petrochemical electric furnace with uniform heating, comprising a furnace wall surrounding a furnace chamber, the inner wall of the furnace wall being lined with a heat-insulating lining, and the furnace chamber being provided with multiple heat exchange tubes, characterized in that: Multiple heat exchange tubes are arranged in multiple rows, and electric heating rods are arranged between each two adjacent rows of heat exchange tubes. The two terminals of the electric heating rods extend out of the furnace wall, and the electric heating rods are distributed side by side with the heat exchange tubes. A thermocouple is arranged between each pair of adjacent rows of heat exchange tubes. The thermocouples and electric heating rods are connected to a control module located outside the furnace chamber. The control module controls the heating power of each row of electric heating rods based on the temperature signals fed back by multiple thermocouples.

2. The petrochemical electric furnace with uniform heating according to claim 1, characterized in that: Each row of heat exchange tubes and each row of electric heating rods are arranged along a straight or curved trajectory, and the arrangement trajectory of each row of electric heating rods is parallel to that of each row of heat exchange tubes.

3. The petrochemical electric furnace with uniform heating according to claim 1, characterized in that: Each row of heat exchange tubes and each row of electric heating rods are arranged along a circular trajectory, and each ring of heat exchange tubes and each ring of electric heating rods are arranged sequentially at intervals along a concentric circular trajectory.

4. A petrochemical electric furnace with uniform heating according to claim 2 or 3, characterized in that: Among the multiple electric heating rods arranged between each pair of adjacent rows of heat exchange tubes: Each electric heating rod is a single, continuous structure; or: multiple electric heating rods are provided along the length of the heat exchange tube.

5. A petrochemical electric furnace with uniform heating according to claim 4, characterized in that: If the electric heating rod is a single piece, the thermocouple is placed near the middle of the electric heating rod; Alternatively: The electric heating rod has a segmented structure, and multiple electric heating rods at the same height of the heat exchange tube are connected to form a group of electric heating rods, with thermocouples installed on the side of each group of electric heating rods.

6. A petrochemical electric furnace with uniform heating according to claim 5, characterized in that: It includes multiple heat exchange modules, each of which includes the furnace wall, the heat exchange tube and the electric heating rod, and the multiple heat exchange modules are stacked longitudinally or laterally.

7. A petrochemical electric furnace with uniform heating according to claim 2 or 3, characterized in that: In each row of heat exchange tubes, the ends of two adjacent heat exchange tubes are connected by an elbow, so that each row of heat exchange tubes is connected in series, and the ends of the first and last heat exchange tubes in each row are sealed and pass through the furnace wall.

8. A petrochemical electric furnace with uniform heating according to claim 1, characterized in that: The electric heating rod is a graphite carbon rod.

9. A petrochemical electric furnace with uniform heating according to claim 1 or 8, characterized in that: The electric heating rod has a constant diameter structure; or: the electric heating rod has a non-constant diameter structure with the diameter varying in stages or gradually upwards.

10. A petrochemical electric furnace with uniform heating according to claim 1, characterized in that: Metal fins are provided between two adjacent heat exchange tubes, so that each row of heat exchange tubes is connected to form a whole screen structure; and / or: the furnace chamber is a sealed chamber, and the furnace wall is provided with an inert gas input pipe that connects to the furnace chamber.

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