Tubular heating furnace

Abstract

The utility model discloses a tubular heating furnace, which comprises a radiation chamber, a heating chamber, a heating chamber, a heating chamber, a heating chamber and a heating chamber, the radiation chamber comprises a bottom wall, a top wall and a side wall, and the bottom wall, the top wall and the side wall jointly form an accommodating space; the furnace tube is located in the containing space, and the furnace tube is used for allowing a to-be-heated process medium to pass through; the combustor is arranged on the bottom wall; and the electric heating element is arranged on the side wall, and the projection of the furnace tube on the bottom wall is located between the projection of the electric heating element on the bottom wall and the combustor. According to the tubular heating furnace, the furnace tube can be heated more uniformly.

Description

Technical Field

[0001] This application relates to the field of petrochemical technology, and more specifically to a tubular heating furnace. Background Technology

[0002] Tubular furnaces are open-flame heating devices used in industries such as petroleum, chemical, coal chemical, oil fields, and long-distance pipelines to heat process media or for pyrolysis reactions. Tubular furnaces generate heat by burning fuel gas or fuel oil and typically consist of a radiant chamber, a convection chamber, a burner, a waste heat recovery system, and a flue gas duct system.

[0003] For tubular furnaces like these, the control of the furnace is relatively complex due to the process characteristics and system composition of the equipment (for example, there are technical challenges such as multivariable, nonlinear, pure time delay, multi-constraint and multi-objective control), making it difficult to ensure the safe, stable, long-term, full-capacity and high-quality operation of the furnace.

[0004] Therefore, improvements are needed to at least partially address the aforementioned issues. Utility Model Content

[0005] The utility model description section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This utility model description section is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To at least partially solve the above problems, this utility model provides a tubular heating furnace, comprising:

[0007] A radiation chamber, comprising a bottom wall, a top wall, and side walls, wherein the bottom wall, the top wall, and the side walls together form an accommodating space;

[0008] A furnace tube, located in the accommodating space, is used to supply the process medium to be heated;

[0009] The burner is disposed on the bottom wall;

[0010] An electric heating element is disposed on the side wall, wherein the projection of the furnace tube on the bottom wall is located between the projection of the electric heating element on the bottom wall and the burner.

[0011] For example, the heating element includes a plurality of resistance wires or resistance strips spaced apart in a vertical direction:

[0012] The tubular furnace also includes multiple power regulators, each of which is connected to a resistance wire or a resistance band.

[0013] For example, the tubular furnace further includes:

[0014] The temperature sensor is provided in multiple locations, which are arranged at intervals in the vertical direction. Each temperature sensor is used to detect the temperature of the process medium to be heated or the temperature of the furnace tube at different heights.

[0015] A controller, connected to the burner, a plurality of power regulators and a plurality of temperature sensors, is used to adjust at least one of the heating power of the electric heating element, the fuel gas flow rate of the burner and the combustion air flow rate of the burner based on the detection results of the plurality of temperature sensors.

[0016] For example, the controller is a programmable logic controller or a microcontroller.

[0017] For example, the temperature sensor is a thermocouple.

[0018] For example, the furnace tube is a vertical tube, a horizontal tube, a spiral tube, or a U-shaped tube.

[0019] For example, the radiation chamber is cylindrical or box-shaped.

[0020] For example, the bottom wall, the top wall and the inner side of the side wall are all provided with fire-resistant linings.

[0021] For example, the tubular furnace further includes a convection chamber disposed at the top of the radiation chamber.

[0022] According to the tubular heating furnace of this application, the burner and electric heating elements can heat the furnace tube and the process medium inside it from both sides of the furnace tube. On the one hand, when a large amount of heat is required during the start-up phase of the tubular heating furnace, the burner can be used as the main heat source and the electric heating elements as auxiliary heat sources to heat the furnace tube and the process medium inside it. When the tubular heating furnace is in a stable operation phase, the electric heating elements can be used as the main heat source and the burner as auxiliary heat sources to heat the furnace tube and the process medium inside it. The electric heating elements are easier to control than the burner, thereby effectively reducing the complexity of furnace control. On the other hand, the fact that the burner and electric heating elements can heat the furnace tube and the process medium inside it from both sides of the furnace tube can make the furnace tube heated more evenly. Attached Figure Description

[0023] The following drawings, which are incorporated herein by reference and are used to understand this application, illustrate embodiments of the invention and their descriptions, thereby explaining the apparatus and principles of the invention. In the drawings,

[0024] Figure 1 This is a schematic diagram of the structure of a tubular heating furnace according to an embodiment of this application;

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

[0026] 10-Radiation chamber; 11-Bottom wall; 12-Side wall; 13-Top wall; 20-Furnace tube; 30-Burner; 40-Heating element; 50-Convection section. Detailed Implementation

[0027] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0028] It should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0029] It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or parts, these elements, components, areas, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or part from another element, component, area, layer, or part. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or part discussed below may be referred to as the second element, component, area, layer, or part.

[0030] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used here for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of devices in use and operation.

[0031] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0032] Embodiments of the utility model are described herein with reference to cross-sectional views that serve as schematic diagrams of preferred embodiments (and intermediate structures) of this application. Thus, variations in the shown shape can be anticipated due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of this application should not be limited to the specific shapes shown herein, but include shape deviations due to, for example, manufacturing processes. Consequently, the figures are substantially schematic, and their shapes are not intended to show the actual shape of the device and are not intended to limit the scope of this application.

[0033] See attached document Figure 1 An exemplary description of a tubular heating furnace according to an embodiment of this application is provided. The tubular heating furnace includes a radiant chamber 10, a burner 30, a furnace tube 20, and an electric heating element 40.

[0034] The radiant chamber 10 includes a bottom wall 11, side walls 12, and a top wall 13, which together form a receiving space. The furnace tube 20 is located within this receiving space. The furnace tube 20 can be a vertical tube, horizontal tube, spiral tube, or U-shaped tube, and is used to supply the process medium to be heated. Supports and hangers for the furnace tube 20 are provided within the receiving space to support and fix the furnace tube 20. These supports and hangers can be fixed to the bottom wall 11 and / or the top wall 13. The radiant chamber 10 can be cylindrical or box-shaped; that is, the tubular furnace can be a cylindrical furnace or a box-shaped furnace.

[0035] The burner 30 is disposed on the bottom wall 11, and the heating element 40 is disposed on the side wall 12. The projection of the furnace tube 20 on the bottom wall 11 is located between the projection of the heating element 40 on the bottom wall 11 and the burner 30. Thus, the burner 30 and the heating element 40 can heat the furnace tube 20 and the process medium therein from both sides of the furnace tube 20. For example, when the radiation chamber 10 is cylindrical, the burner 30 can be disposed at the center of the bottom wall 11, and the furnace tube 20 can be a spiral tube. The projection of the furnace tube 20 on the bottom wall 11 surrounds the burner 30 circumferentially, and the projection of the heating element 40 on the bottom wall 11 surrounds the projection of the furnace tube 20 on the bottom wall 11 circumferentially. For example, when the radiant chamber 10 is box-shaped, there can be multiple burners 30, which are spaced apart on the bottom wall 11 along a first direction. The projection of the furnace tube 20 on the bottom wall 11 is located on both sides of the burner 30 in a second direction, which is perpendicular to the first direction. The projection of the electric heating element 40 on the bottom wall 11 is located on the side of the furnace tube 20 on the bottom wall 11 away from the burner 30.

[0036] According to the tubular furnace of the present application embodiment, on the one hand, when a large amount of heat is required during the start-up phase of the tubular furnace, the furnace tube 20 and the process medium inside it can be heated by the burner 30 as the main heat source and the electric heating element 40 as the auxiliary heat source. At this time, the heat supplied by the burner 30 is greater than the heat supplied by the electric heating element 40. When the tubular furnace is in a stable operation phase, the electric heating element 40 can be used as the main heat source and the burner 30 as the auxiliary heat source to heat the furnace tube 20 and the process medium inside it. At this time, the heat supplied by the electric heating element 40 is greater than the heat supplied by the burner 30. The burner 30 can be controlled to supply heat at a fixed amount. The temperature of the radiation chamber 10 or the temperature of the process medium can be adjusted by adjusting the heat supply of the electric heating element 40. The electric heating element 40 is easier to control than the burner 30, thereby effectively reducing the complexity of furnace control. On the other hand, the burner 30 and the electric heating element 40 can heat the furnace tube 20 and the process medium inside it from both sides of the furnace tube 20, which can make the furnace tube 20 more evenly heated. Furthermore, the tubular heating furnace in this embodiment uses both burner 30 and electric heating element 40 for heating, which can effectively reduce carbon and air pollutant emissions compared to using burner 30 alone for heating.

[0037] For example, the bottom wall 11, side walls 12, and top wall 13 are all steel structures, each with a refractory lining on its inner side. The refractory lining on the inner side of the bottom wall 11 may include refractory bricks and / or refractory castables, the refractory lining on the inner side of the side wall 12 may include refractory bricks and / or refractory fibers, and the refractory lining on the inner side of the top wall 13 may include refractory fibers. The heating element 40 can be fixedly connected to the side wall 12 by anchors or other suitable fasteners, located on the side of the refractory lining away from the side wall 12.

[0038] In this embodiment, the heating element 40 includes a plurality of resistance wires or resistance strips spaced vertically. The tubular furnace also includes a plurality of power regulators (not shown in the figure), each connected to a resistance wire or resistance strip. The power regulators are used to adjust the heating power of the resistance wire or resistance strip, thereby adjusting its heat supply. Exemplarily, each resistance wire or resistance strip can be arranged horizontally along the side wall 12. Since the burner 30 is located on the bottom wall 11, generally, the furnace tubes 20 near the bottom wall 11 have a relatively higher temperature because they are closer to the burner 30, while the furnace tubes 20 near the top wall 13 have a relatively lower temperature because they are farther from the burner 30. Therefore, there is a certain degree of uneven heating in the vertical direction of the furnace tubes 20. In this embodiment, for multiple resistance wires or resistance strips spaced vertically, their heating power can be adjusted by a power regulator, so that the resistance wires or resistance strips near the top wall 13 (higher in the vertical direction) are heated with greater power, and the resistance wires or resistance strips near the bottom wall 11 (lower in the vertical direction) are heated with lower power. That is, the heating power of multiple resistance wires or resistance strips gradually increases from low to high in the vertical direction, thereby compensating for the uneven heating of the furnace tube 20 caused by the burner 30, and making the furnace tube 20 heated evenly in the vertical direction.

[0039] In this embodiment, the tubular furnace further includes temperature sensors and a controller. Multiple temperature sensors are arranged vertically at intervals, each used to detect the temperature of the process medium to be heated at different heights or the temperature of the furnace tube 20 at different heights. The controller is connected to the burner 30, multiple power regulators, and multiple temperature sensors, and is used to adjust at least one of the following based on the detection results of the multiple temperature sensors: the heating power of the electric heating element 40 (adjusted via the power regulators), the fuel gas flow rate of the burner 30, and the combustion air flow rate of the burner 30. For example, the burner 30 has a fuel gas pipeline, a combustion air pipeline, a fuel gas flow control valve disposed on the fuel gas pipeline, and a combustion air flow control valve disposed on the combustion air pipeline. The controller can be connected to the fuel gas flow control valve and the combustion air flow control valve, and by controlling the opening degree of the fuel gas flow control valve and the combustion air flow control valve, adjust the fuel gas flow rate and / or the combustion air flow rate of the burner 30 to achieve adjustment of the heating supply of the burner 30.

[0040] In some embodiments, the controller can adjust at least one of the heating power of the heating element 40 (adjusted by a power regulator), the fuel gas flow rate of the burner 30, and the combustion air flow rate of the burner 30, so that the detection results of multiple temperature sensors are simultaneously within a preset temperature range, that is, so that the temperature of the process medium to be heated at different heights in the vertical direction or the temperature of the furnace tube 20 are the same or similar, so that the furnace tube 20 and the process medium therein are heated uniformly in the vertical direction.

[0041] In some embodiments, the controller can adjust at least one of the heating power of the heating element 40 (adjusted via a power regulator), the fuel gas flow rate of the burner 30, and the combustion air flow rate of the burner 30, so that the detection results of each temperature sensor are within different preset temperature ranges (i.e., each temperature sensor corresponds to a preset temperature range). This creates a specific temperature gradient between the temperature of the process medium to be heated or the temperature of the furnace tube 20 at different heights in the vertical direction, thereby meeting the heating requirements of a specific process medium. For example, when the detection result of a temperature sensor at a certain height exceeds its corresponding preset range, the heating power of the heating element 40 at or near that height can be adjusted so that the detection result of that temperature sensor falls back into and remains within the preset temperature range.

[0042] For example, the temperature sensor can be a thermocouple or other suitable temperature sensor, and the controller can be a programmable logic controller (PLC), a microcontroller, or other suitable control device. The controller has a PID parameter self-tuning function, capable of processing the temperature feedback from the temperature sensor using a PID algorithm, inputting at least one of the control parameters for the heating power of the heating element 40, the fuel gas flow rate of the burner 30, and the combustion air flow rate of the burner 30, and performing corresponding control to ensure that the temperature sensor's detection result is within a specific range. In this embodiment, the controller is connected to the heating element 40 via a power regulator. The controller is used to adjust the heating power of the heating element 40 via the power regulator, for example, by adjusting the voltage or current supplied to the heating element 40. In some embodiments, the heating element 40 itself has elements for power regulation, and the controller is connected to the heating element 40 to directly control the heating element 40 to adjust its heating power.

[0043] For example, the tubular furnace also includes a convection chamber 50 disposed at the top of the radiation chamber 10.

[0044] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0045] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0046] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0047] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or elements of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature serving the same, equivalent, or similar purpose.

[0048] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0049] It should be noted that the above embodiments are illustrative of this application and not restrictive of this application, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims.

Claims

1. A tubular heating furnace, characterized in that, include: A radiation chamber, comprising a bottom wall, a top wall, and side walls, wherein the bottom wall, the top wall, and the side walls together form an accommodating space; Furnace tube, located within the accommodating space, is used for supplying the process medium to be heated: The burner is disposed on the bottom wall; An electric heating element is disposed on the side wall, wherein the projection of the furnace tube on the bottom wall is located between the projection of the electric heating element on the bottom wall and the burner.

2. The tubular heating furnace according to claim 1, characterized in that, The heating element includes a plurality of resistance wires or resistance strips spaced apart in the vertical direction; The tubular furnace also includes multiple power regulators, each of which is connected to a resistance wire or a resistance band.

3. The tubular heating furnace according to claim 2, characterized in that, The tubular heating furnace also includes: The temperature sensor is provided in multiple locations, which are arranged at intervals in the vertical direction. Each of the multiple temperature sensors is used to detect the temperature of the process medium to be heated or the temperature of the furnace tube at different heights. A controller, connected to the burner, a plurality of power regulators and a plurality of temperature sensors, is used to adjust at least one of the heating power of the electric heating element, the fuel gas flow rate of the burner and the combustion air flow rate of the burner based on the detection results of the plurality of temperature sensors.

4. The tubular heating furnace according to claim 3, characterized in that, The controller is a programmable logic controller or a microcontroller.

5. The tubular heating furnace according to claim 3, characterized in that, The temperature sensor is a thermocouple.

6. The tubular heating furnace according to claim 1, characterized in that, The furnace tube is a vertical tube, a horizontal tube, a spiral tube, or a U-shaped tube.

7. The tubular heating furnace according to claim 1, characterized in that, The radiation chamber is cylindrical or box-shaped.

8. The tubular heating furnace according to claim 1, characterized in that, The bottom wall, the top wall, and the inner side of the side wall are all provided with fire-resistant linings.

9. The tubular heating furnace according to claim 1, characterized in that, The tubular furnace also includes a convection chamber, which is located at the top of the radiation chamber.

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