Tubular heating furnace

Abstract

The invention 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] The present application relates to the field of petrochemical technology, and in particular to a tubular heating furnace. Background Art

[0002] Tubular heating furnace is an open flame heating equipment used to heat process media or cracking reactions in industries such as petroleum, chemical industry, coal chemical industry, oil fields and long-distance pipelines. Tubular heating furnace generates heat source by burning fuel gas or fuel oil, and is generally composed of radiation chamber, convection chamber, burner, waste heat recovery system and smoke and air duct system.

[0003] For such tubular heating furnaces, due to the process characteristics and system composition of the device, the control of the heating furnace is relatively complex (for example, there are technical difficulties such as multi-variable, nonlinear, pure lag, multi-constraint and multi-objective regulation), making it difficult to ensure the "safe, stable, long-term, full and optimal" operation of the heating furnace.

[0004] Therefore, improvements are needed to at least partially solve the above problems. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention, which will be further described in detail in the Detailed Description of the Invention. The Summary of the Invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] In order to at least partially solve the above problems, the present invention provides a tubular heating furnace, which comprises:

[0007] A radiation chamber, the 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 a receiving space;

[0008] A furnace tube, the furnace tube is located in the accommodating space, and the furnace tube is used for allowing a process medium to be heated to pass through;

[0009] a burner, the burner being arranged on the bottom wall;

[0010] An electric heating element is arranged 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] Exemplarily, the electric heating element includes a plurality of resistance wires or resistance belts spaced apart in the vertical direction;

[0012] The tubular heating furnace further comprises a plurality of power regulators, each of which is connected to one of the resistance wires or the resistance belts.

[0013] Exemplarily, the tubular heating furnace further comprises:

[0014] A temperature sensor, wherein there are a plurality of the temperature sensors, the plurality of the temperature sensors are arranged at intervals in the vertical direction, and the plurality of the temperature sensors are respectively used to detect the temperature of the process medium to be heated at different heights or the temperature of the furnace tube at different heights;

[0015] A controller is connected to the burner, the multiple power regulators and the multiple temperature sensors, and 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 according to the detection results of the multiple temperature sensors, so that the detection results of the multiple temperature sensors are simultaneously in a preset temperature range, or the detection results of each temperature sensor are in a different preset temperature range.

[0016] Exemplarily, the controller is a programmable logic controller or a single chip microcomputer.

[0017] Exemplarily, the temperature sensor is a thermocouple.

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

[0019] Exemplarily, the radiation chamber is cylindrical or square box-shaped.

[0020] Exemplarily, the bottom wall, the top wall and the inner sides of the side walls are all provided with refractory linings.

[0021] Exemplarily, the tubular heating furnace further comprises a convection chamber, wherein the convection chamber is disposed on the top of the radiation chamber.

[0022] According to the tubular heating furnace of the present application, the burner and the electric heating element can heat the furnace tube and the process medium therein on both sides of the furnace tube. On the one hand, when a large amount of heat is required during the start-up stage of the tubular heating furnace, the burner can be used as the main and the electric heating element can be used as the auxiliary to heat the furnace tube and the process medium therein. When the tubular heating furnace is in a stable operation stage, the electric heating element can be used as the main burner as the auxiliary to heat the furnace tube and the process medium therein. Compared with the burner, the electric heating element is easier to control, thereby effectively reducing the complexity of the heating furnace control. On the other hand, the burner and the electric heating element can heat the furnace tube and the process medium therein on both sides of the furnace tube, so that the furnace tube can be heated more evenly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following drawings of the present application are hereby used as part of the present application for understanding the present application. The drawings show the embodiments of the present application and their descriptions, and are used to explain the device and principle of the present application. In the drawings,

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

[0025] Description of reference numerals:

[0026] 10- radiation chamber 11- bottom wall, 12- side wall, 13- top wall, 20- furnace tube, 30- burner, 40- electric heating element, 50- convection chamber. DETAILED DESCRIPTION

[0027] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0028] It should be understood that the present application can be implemented in different forms and should not be construed as being limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

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

[0030] Spatially relative terms such as "under", "beneath", "below", "under", "above", "above", etc., may be used herein for convenience of description to describe the relationship of one element or feature to other elements or features shown in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation shown in the figures.

[0031] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0032] Embodiments of the invention are described herein with reference to cross-sectional views as schematic diagrams of ideal embodiments (and intermediate structures) of the present application. Thus, variations in the shapes shown due to, for example, manufacturing techniques and / or tolerances can be expected. Therefore, embodiments of the present application should not be limited to the specific shapes shown herein, but include shape deviations due to, for example, manufacturing. Therefore, what is shown in the figures is schematic in nature, and their shapes are not intended to display the actual shape of the device and are not intended to limit the scope of the present application.

[0033] See attached Figure 1 A tubular heating furnace according to an embodiment of the present application is exemplarily described. The tubular heating furnace includes a radiation chamber 10 , a burner 30 , a furnace tube 20 and an electric heating element 40 .

[0034] The radiation chamber 10 includes a bottom wall 11, a side wall 12 and a top wall 13, which together form a receiving space. The furnace pipe 20 is located in the receiving space. The furnace pipe 20 can be a vertical pipe, a horizontal pipe, a spiral pipe or a U-shaped pipe. The furnace pipe 20 is used for passing the process medium to be heated. The furnace pipe 20 support and hanger is provided in the receiving space to support and fix the furnace pipe 20. The furnace pipe 20 support and hanger can be fixed to the bottom wall 11 and / or the top wall 13. The radiation chamber 10 can be cylindrical or square box-shaped, that is, the tubular heating furnace can be a cylindrical furnace or a square box furnace.

[0035] The burner 30 is arranged on the bottom wall 11, and the electric heating element 40 is arranged on the side wall 12, wherein the projection of the furnace tube 20 on the bottom wall 11 is located between the projection of the electric heating element 40 on the bottom wall 11 and the burner 30. Thus, the burner 30 and the electric heating element 40 can heat the furnace tube 20 and the process medium therein on both sides of the furnace tube 20. Exemplarily, when the radiation chamber 10 is cylindrical, the burner 30 can be arranged at the center of the bottom wall 11, 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 in the circumferential direction, and the projection of the electric heating element 40 on the bottom wall 11 surrounds the projection of the furnace tube 20 on the bottom wall 11 in the circumferential direction. Exemplarily, when the radiation chamber 10 is in a square box shape, there may be multiple burners 30, which are arranged at intervals on the bottom wall 11 along a first direction, and 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, the second direction is perpendicular to the first direction, and the projection of the electric heating element 40 on the bottom wall 11 is located on the side of the projection of the furnace tube 20 on the bottom wall 11 away from the burner 30.

[0036] According to the tubular heating furnace of the embodiment of the present application, on the one hand, when a large amount of heat is required during the start-up phase of the tubular heating furnace, the furnace tube 20 and the process medium therein can be heated with the burner 30 as the main and the electric heating element 40 as the auxiliary. 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 heating furnace is in a stable operation phase, the furnace tube 20 and the process medium therein can be heated with the electric heating element 40 as the main burner 30 as the auxiliary. 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 with a fixed amount of heat, and 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 the heating 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 therein on both sides of the furnace tube 20, so that the furnace tube 20 can be heated more evenly. In addition, the tubular heating furnace of the embodiment of the present application adopts the burner 30 and the electric heating element 40 to jointly provide heat, which can effectively reduce the emission of carbon and atmospheric pollutants compared with simply using the burner 30 for heating.

[0037] Exemplarily, the bottom wall 11, the side wall 12 and the top wall 13 are all steel structures, and a refractory lining is arranged on the inner side thereof. 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 electric heating element 40 may be fixedly connected to the side wall 12 by an anchor or other suitable fixing member, and is located on the side of the refractory lining away from the side wall 12.

[0038] In this embodiment, the electric heating element 40 includes a plurality of resistance wires or resistance belts spaced apart in the vertical direction. The tubular heating furnace also includes a plurality of power regulators (not shown in the figure), each of which is connected to a resistance wire or resistance belt, and the power regulator is used to adjust the heating power of the resistance wire or resistance belt, thereby adjusting the heating amount thereof. Exemplarily, each resistance wire or resistance belt can be arranged horizontally along the side wall 12. Since the burner 30 is arranged on the bottom wall 11, usually, the furnace tube 20 close to the bottom wall 11 is closer to the burner 30 and has a relatively high temperature, and the furnace tube 20 close to the top wall 13 is farther from the burner 30 and has a relatively low temperature, and the furnace tube 20 has a certain degree of uneven heating in the vertical direction. In this embodiment, for the multiple resistance wires or resistance belts spaced apart in the vertical direction, their heating power can be adjusted by a power regulator, so that the resistance wire or resistance belt close to the top wall 13 (with a higher height in the vertical direction) can provide heat with a higher power, and the resistance wire or resistance belt close to the bottom wall 11 (with a lower height in the vertical direction) can provide heat with a lower power, that is, the heating power of the multiple resistance wires or resistance belts 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, so that the furnace tube 20 can be heated evenly in the vertical direction.

[0039] In this embodiment, the tubular heating furnace further includes a temperature sensor and a controller. There are multiple temperature sensors, which are arranged at intervals in the vertical direction, and the multiple temperature sensors are respectively 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 the heating power of the electric heating element 40 (adjusted by the power regulator), the fuel gas flow rate of the burner 30, and the combustion air flow rate of the burner 30 according to the detection results of the multiple temperature sensors. Exemplarily, the burner 30 has a fuel gas pipeline, a combustion air pipeline, a fuel gas flow control valve arranged on the fuel gas pipeline, and a combustion air flow control valve arranged on the combustion air pipeline. The controller can be connected to the fuel gas flow control valve and the combustion air flow control valve for control, and the fuel gas flow rate of the burner 30 and / or the combustion air flow rate of the burner 30 are adjusted by controlling the opening of the fuel gas flow control valve and the combustion air flow control valve to adjust the heat supply of the burner 30.

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

[0041] In some embodiments, the controller can adjust at least one of the heating power of the electric heating element 40 (adjusted by the 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 result of each temperature sensor is in a different preset temperature range (that is, each temperature sensor corresponds to a preset temperature range), that is, the temperature of the process medium to be heated or the temperature of the furnace tube 20 at different heights in the vertical direction forms a specific temperature gradient, thereby meeting the heating requirements of the 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 electric heating element 40 at the corresponding height or adjacent to the height can be adjusted so that the detection result of the temperature sensor falls back into and remains in the preset temperature range.

[0042] Exemplarily, the temperature sensor can be a thermocouple or other suitable temperature sensor, and the controller can be a programmable logic controller (PLC) or a single chip microcomputer or other suitable control device. The controller has a PID parameter self-tuning function, can perform PID algorithm processing on the temperature feedback of the temperature sensor, input the control parameters of at least one of the heating power of the electric heating element 40, the fuel gas flow of the burner 30 and the combustion air flow of the burner 30, and perform corresponding control so that the detection result of the temperature sensor is within a specific range. In an embodiment of the present application, the controller is connected to the electric heating element 40 through a power regulator, and the controller is used to adjust the heating power of the electric heating element 40 through the power regulator, for example, by adjusting the voltage or current provided to the electric heating element 40 through the power regulator to adjust its heating power. In some embodiments, the electric heating element 40 itself has an element for power regulation, and the controller is connected to the electric heating element 40 to directly control the electric heating element 40 to adjust its heating power.

[0043] Exemplarily, the tubular heating furnace further includes a convection chamber 50 , which is disposed on the top of the radiation chamber 10 .

[0044] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0045] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0046] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0047] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0048] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0049] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims.

Claims

1. A tubular heating furnace, characterized in that: include: A radiation chamber, the 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 a receiving space; A furnace tube, the furnace tube is located in the accommodating space, and the furnace tube is used for allowing a process medium to be heated to pass through; a burner, the burner being arranged on the bottom wall; An electric heating element is arranged 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 electric heating element comprises a plurality of resistance wires or resistance belts arranged at intervals in the vertical direction; The tubular heating furnace further comprises a plurality of power regulators, each of which is connected to one of the resistance wires or the resistance belts.

3. The tubular heating furnace according to claim 2, characterized in that: The tubular heating furnace also includes: A temperature sensor, wherein there are a plurality of the temperature sensors, and the plurality of the temperature sensors are arranged at intervals in the vertical direction, and the plurality of the temperature sensors are respectively used to detect the temperature of the process medium to be heated at different heights or the temperature of the furnace tube at different heights; A controller is connected to the burner, the multiple power regulators and the multiple temperature sensors, and 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 according to the detection results of the multiple temperature sensors, so that the detection results of the multiple temperature sensors are simultaneously in a preset temperature range, or the detection results of each temperature sensor are in a different preset temperature range.

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

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 in a cylindrical or square box shape.

8. The tubular heating furnace according to claim 1, characterized in that: The bottom wall, the top wall and the inner sides of the side walls are all provided with refractory linings.

9. The tubular heating furnace according to claim 1, characterized in that: The tubular heating furnace further comprises a convection chamber, which is arranged on the top of the radiation chamber.

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