A tube row structure of a U-shaped furnace tube heating furnace

Abstract

This invention discloses a tube array structure for a U-shaped furnace tube heater. The U-shaped furnace tubes are divided into a first U-shaped furnace tube (1) and a second U-shaped furnace tube (2), which are alternately arranged along the axial direction of the inlet manifold (7) and the outlet manifold (8). The inlet (3) of the first U-shaped furnace tube and the inlet (5) of the second U-shaped furnace tube are connected to the lower part of the inlet manifold, and the outlet (4) of the first U-shaped furnace tube and the outlet (6) of the second U-shaped furnace tube are connected to the lower part of the outlet manifold. Between the inlet of the first U-shaped furnace tube and the inlet of the second U-shaped furnace tube, the inlet of the second U-shaped furnace tube is adjacent to the outlet manifold; between the outlet of the first U-shaped furnace tube and the outlet of the second U-shaped furnace tube, the outlet of the second U-shaped furnace tube or the outlet of the first U-shaped furnace tube is adjacent to the inlet manifold. This invention can be used in U-shaped furnace tube heaters for reforming, disproportionation, and isomerization units in the petroleum refining industry.

Description

Technical Field

[0001] This invention belongs to the technical field of tubular heating furnaces in petroleum refining, and relates to a tube bank structure for a U-shaped tube heating furnace. Background Technology

[0002] In recent years, due to stringent environmental protection requirements and the trend towards larger-scale oil refining plants, heating furnaces need higher heat loads to process large quantities of materials, necessitating larger furnaces to meet increasingly demanding operational requirements. Currently, the main method for increasing the heat load of heating furnaces is to increase the heat transfer area, which can be achieved by increasing the length and number of furnace tubes. However, considering investment constraints and the need to meet overall plant planning requirements, there is often insufficient land and funds to construct large-scale heating furnaces. Existing U-tube heating furnaces using U-shaped furnace tubes employ a single row of U-shaped tubes. The inlets of multiple U-shaped furnace tubes are connected to an inlet manifold, arranged in a straight line along the axial direction of the inlet manifold; the outlets of multiple U-shaped furnace tubes are connected to an outlet manifold, also arranged in a straight line along the axial direction of the outlet manifold. When the heat load requirement is high and the overall size of the heating furnace is limited, this arrangement of U-shaped furnace tubes is restricted by the structure of the welded joints at the inlet and outlet of the U-shaped furnace tubes and the manufacturing process of the manifold. A certain distance must be maintained between adjacent furnace tube inlets and between adjacent furnace tube outlets. Therefore, it is impossible to add furnace tubes, and the furnace chamber space of the heating furnace cannot be fully utilized, the heat transfer area cannot be increased, and the heat load of the heating furnace cannot be improved. Summary of the Invention

[0003] The purpose of this invention is to provide a tube bank structure for a U-shaped tube heating furnace, so as to solve the problems of existing tube bank structures that cannot add new furnace tubes, cannot make full use of the furnace space, increase the heat transfer area, and increase the heat load of the heating furnace.

[0004] To solve the above problems, the technical solution adopted by the present invention is: a tube bank structure for a U-shaped furnace tube heating furnace, comprising U-shaped furnace tubes, characterized in that: the U-shaped furnace tubes are divided into first U-shaped furnace tubes and second U-shaped furnace tubes, each having several first U-shaped furnace tubes and second U-shaped furnace tubes, alternately arranged along the axial direction of the inlet manifold and the outlet manifold; the inlet of the first U-shaped furnace tube and the inlet of the second U-shaped furnace tube are connected to the lower part of the inlet manifold; the outlet of the first U-shaped furnace tube and the outlet of the second U-shaped furnace tube are connected to the lower part of the outlet manifold; between the inlet of the first U-shaped furnace tube and the inlet of the second U-shaped furnace tube, the inlet of the second U-shaped furnace tube is adjacent to the outlet manifold; between the outlet of the first U-shaped furnace tube and the outlet of the second U-shaped furnace tube, the outlet of the second U-shaped furnace tube is adjacent to the inlet manifold; the inlet of the first U-shaped furnace tube and the inlet of the second U-shaped furnace tube are arranged in an isosceles triangle on the horizontal projection plane; the outlet of the first U-shaped furnace tube and the outlet of the second U-shaped furnace tube are arranged in an isosceles triangle on the horizontal projection plane; the minimum value of the leg length 'a' of the isosceles triangle is 1.8 times the outer diameter of the furnace tube, and the minimum value of the base length 'b' is 2 times the outer diameter of the furnace tube.

[0005] Alternatively, between the first U-shaped furnace tube inlet and the second U-shaped furnace tube inlet, the second U-shaped furnace tube inlet is adjacent to the outlet manifold, and between the first U-shaped furnace tube outlet and the second U-shaped furnace tube outlet, the first U-shaped furnace tube outlet is adjacent to the inlet manifold. The first U-shaped furnace tube inlet and the second U-shaped furnace tube inlet are arranged in an equilateral triangle on the horizontal projection plane, and the first U-shaped furnace tube outlet and the second U-shaped furnace tube outlet are arranged in an equilateral triangle on the horizontal projection plane. The minimum value of the side length c of the equilateral triangle is 2.2 times the outer diameter of the furnace tube.

[0006] The present invention offers the following advantages: Using a first U-shaped furnace tube and a second U-shaped furnace tube, and employing the aforementioned arrangement, it allows for the formation of first U-shaped furnace tube rows and second U-shaped furnace tube rows within the furnace chamber while maintaining the welded joint structures at the inlet and outlet of the first and second U-shaped furnace tubes, and ensuring a certain distance between adjacent inlets and outlets. This significantly increases the number of furnace tubes within a given furnace chamber volume, fully utilizing the furnace space, effectively increasing the heat transfer area, and enhancing the furnace's heat load. The lengths of the inlet and outlet manifolds can also be effectively controlled, eliminating the need for extension. The invention features a simple structure and convenient construction, enabling it to meet the higher heat load requirements of the process while controlling the overall size and volume of the furnace and without increasing the floor space.

[0007] This invention relates to U-tube heaters used in reforming, disproportionation, and isomerization units in the petroleum refining industry, where the U-tube heater is used to heat the feed material. This invention can be used for building new heaters or for upgrading existing ones. When upgrading existing heaters, only the U-tubes, inlet manifold, outlet manifold, and burner need to be replaced (with a higher-power burner), thus requiring minimal investment.

[0008] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The accompanying drawings and specific embodiments do not limit the scope of protection claimed by the present invention. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the first embodiment of the tube bank structure of the U-shaped furnace tube heating furnace of the present invention.

[0010] Figure 2 This is a schematic diagram of the second embodiment of the tube bank structure of the U-shaped furnace tube heating furnace of the present invention.

[0011] Figure 3 yes Figure 1 Sectional view (partial) of section A-A.

[0012] Figure 4 yes Figure 2 Partial B-B sectional view.

[0013] Figures 1 to 4 In this drawing, the same reference numerals indicate the same technical features. Reference numerals indicate: 1—first U-shaped furnace tube; 2—second U-shaped furnace tube; 3—inlet of first U-shaped furnace tube; 4—outlet of first U-shaped furnace tube; 5—inlet of second U-shaped furnace tube; 6—outlet of second U-shaped furnace tube; 7—inlet manifold; 8—outlet manifold; 9—flame injected by the burner. Detailed Implementation

[0014] Figure 1 and Figure 3 The diagram shows the first embodiment of the tube bank structure of the U-shaped furnace tube heating furnace (referred to as the heating furnace) of the present invention. This tube bank structure includes U-shaped furnace tubes, which are divided into a first U-shaped furnace tube 1 and a second U-shaped furnace tube 2. The first U-shaped furnace tube 1 consists of two vertical tubes and one bent tube, with the area enclosed by these three tubes forming the inner side of the first U-shaped furnace tube 1. The second U-shaped furnace tube 2 consists of two vertical tubes and one bent tube, with the area enclosed by these three tubes forming the inner side of the second U-shaped furnace tube 1. A number of first U-shaped furnace tubes 1 and second U-shaped furnace tubes 2 are arranged (generally 20 to 70 each), alternating along the axial direction (i.e., the length direction) of the inlet manifold 7 and the outlet manifold 8. The inlet manifold 7 and the outlet manifold 8 are parallel straight tubes, horizontally positioned at the top of the heating furnace's radiation chamber. The cross-sectional shape of the first U-shaped furnace tube 1 and the second U-shaped furnace tube 2 is circular, with an outer diameter generally between 60 and 160 mm. The inlet manifold 7 and the outlet manifold 8 have circular cross-sectional shapes, and their outer diameters are generally 500 to 1600 mm.

[0015] The first U-shaped furnace tube inlet 3 and the second U-shaped furnace tube inlet 5 are connected to the lower part of the inlet manifold 7, and the first U-shaped furnace tube outlet 4 and the second U-shaped furnace tube outlet 6 are connected to the lower part of the outlet manifold 8. All connections are welded. Between the first U-shaped furnace tube inlet 3 and the second U-shaped furnace tube inlet 5, the second U-shaped furnace tube inlet 5 is adjacent to the outlet manifold 8; between the first U-shaped furnace tube outlet 4 and the second U-shaped furnace tube outlet 6, the second U-shaped furnace tube outlet 6 is adjacent to the inlet manifold 7. The first U-shaped furnace tube inlet 3 and the second U-shaped furnace tube inlet 5 are arranged in an isosceles triangle on the horizontal projection plane, and the first U-shaped furnace tube outlet 4 and the second U-shaped furnace tube outlet 6 are also arranged in an isosceles triangle on the horizontal projection plane. The minimum value of the leg length 'a' of the isosceles triangle is 1.8 times the outer diameter of the furnace tube, and the minimum value of the base length 'b' is 2 times the outer diameter of the furnace tube (see [reference]). Figure 3The furnace tubes referred to are the first U-shaped furnace tube 1 and the second U-shaped furnace tube 2, which have the same outer diameter. The leg length 'a' of the isosceles triangle refers to the center distance between adjacent first U-shaped furnace tube inlets 3 and 5, and between adjacent first U-shaped furnace tube outlets 4 and 6. The base length 'b' of the isosceles triangle refers to the center distance between adjacent first U-shaped furnace tube inlets 3, adjacent second U-shaped furnace tube inlets 5, adjacent first U-shaped furnace tube outlets 4, and adjacent second U-shaped furnace tube outlets 6. The value of b is generally less than the value of c as described below, which also results in smaller spacing between adjacent first U-shaped furnace tubes 1, second U-shaped furnace tubes 2, and between first U-shaped furnace tubes 1 and second U-shaped furnace tubes 2 along the axial direction of the inlet manifold 7 and outlet manifold 8; when the lengths of the inlet manifold 7 and outlet manifold 8 and the outer diameters of the first U-shaped furnace tubes 1 and second U-shaped furnace tubes 2 are constant, the number of first U-shaped furnace tubes 1 and second U-shaped furnace tubes 2 is greater than that in the second embodiment of the present invention. See also Figure 1 and Figure 3 In the first embodiment of the present invention, on a vertical projection plane perpendicular to the inlet manifold 7 and the outlet manifold 8, the second U-shaped furnace 2 is located inside the first U-shaped furnace tube 1.

[0016] Figure 2 and Figure 4 The second embodiment of the tube bank structure of the U-shaped furnace heating furnace of the present invention is shown. Between the first U-shaped furnace tube inlet 3 and the second U-shaped furnace tube inlet 5, the second U-shaped furnace tube inlet 5 is adjacent to the outlet manifold 8; between the first U-shaped furnace tube outlet 4 and the second U-shaped furnace tube outlet 6, the first U-shaped furnace tube outlet 4 is adjacent to the inlet manifold 7. The first U-shaped furnace tube inlet 3 and the second U-shaped furnace tube inlet 5 are arranged in an equilateral triangle on the horizontal projection plane, and the first U-shaped furnace tube outlet 4 and the second U-shaped furnace tube outlet 6 are also arranged in an equilateral triangle on the horizontal projection plane. The minimum value of the side length c of the equilateral triangle is 2.2 times the outer diameter of the furnace tube (see [reference]). Figure 4The side length *c* of the equilateral triangle refers to the center-to-center distance between adjacent first U-shaped furnace tube inlets 3, adjacent second U-shaped furnace tube inlets 5, adjacent first U-shaped furnace tube inlets 3 and 5, adjacent first U-shaped furnace tube outlets 4, adjacent second U-shaped furnace tube outlets 6, and adjacent first U-shaped furnace tube outlets 4 and 6. The value of *c* is generally greater than the value of *b* mentioned above, resulting in larger spacing between adjacent first U-shaped furnace tubes 1, second U-shaped furnace tubes 2, and between first U-shaped furnace tubes 1 and second U-shaped furnace tubes 2 along the axial direction of the inlet manifold 7 and outlet manifold 8. When the lengths of the inlet manifold 7 and outlet manifold 8 and the outer diameters of the first U-shaped furnace tubes 1 and 2 are constant, the number of first U-shaped furnace tubes 1 and 2 is less than in the first embodiment of this invention. See also... Figure 2 and Figure 4 In the second embodiment of the present invention, the first U-shaped furnace tube 1 and the second U-shaped furnace tube 2 are staggered on a vertical projection plane perpendicular to the inlet manifold 7 and the outlet manifold 8. All other structures and arrangements not mentioned in the second embodiment are the same as those in the first embodiment, and will be omitted from the description.

[0017] In this invention, each first U-shaped furnace tube inlet 3 is located on a straight line parallel to the axis of the inlet manifold 7, and each second U-shaped furnace tube inlet 5 is located on another straight line parallel to the axis of the inlet manifold 7. These two lines are generally symmetrical about left and right with respect to a vertical plane passing through the axis of the inlet manifold 7. Each first U-shaped furnace tube outlet 4 is located on a straight line parallel to the axis of the outlet manifold 8, and each second U-shaped furnace tube outlet 6 is located on another straight line parallel to the axis of the outlet manifold 8. These two lines are generally symmetrical about left and right with respect to a vertical plane passing through the axis of the outlet manifold 8. For any first U-shaped furnace tube 1 and second U-shaped furnace tube 2, the two vertical tubes and one bent tube are located on a plane perpendicular to the inlet manifold 7 and the outlet manifold 8.

[0018] The burner in the heating furnace injects flame 9 into the inner side of the first U-shaped furnace tube 1 and the second U-shaped furnace tube 2, such as... Figure 3 and Figure 4 As shown. By employing the arrangement of the first U-shaped furnace tube 1 and the second U-shaped furnace tube 2 and the defined parameters of the present invention, both the first U-shaped furnace tube 1 and the second U-shaped furnace tube 2 can be subjected to flame radiant heat, and the tube closer to the flame does not block the tube farther from the flame.

Claims

1. A tube bank structure for a U-shaped furnace tube heating furnace, comprising U-shaped furnace tubes, characterized in that: The U-shaped furnace tube is divided into a first U-shaped furnace tube (1) and a second U-shaped furnace tube (2). Several first U-shaped furnace tubes (1) and several second U-shaped furnace tubes (2) are arranged alternately along the axial direction of the inlet manifold (7) and the outlet manifold (8). The inlet (3) of the first U-shaped furnace tube and the inlet (5) of the second U-shaped furnace tube are connected to the lower part of the inlet manifold (7). The outlet (4) of the first U-shaped furnace tube and the outlet (6) of the second U-shaped furnace tube are connected to the lower part of the outlet manifold (8). Between the inlet (3) of the first U-shaped furnace tube and the inlet (5) of the second U-shaped furnace tube... The furnace tube inlet (5) is adjacent to the outlet manifold (8), between the first U-shaped furnace tube outlet (4) and the second U-shaped furnace tube outlet (6). The second U-shaped furnace tube outlet (6) is adjacent to the inlet manifold (7). The first U-shaped furnace tube inlet (3) and the second U-shaped furnace tube inlet (5) are arranged in an isosceles triangle on the horizontal projection plane. The first U-shaped furnace tube outlet (4) and the second U-shaped furnace tube outlet (6) are arranged in an isosceles triangle on the horizontal projection plane. The minimum value of the leg length a of the isosceles triangle is 1.8 times the outer diameter of the furnace tube, and the minimum value of the base length b is 2 times the outer diameter of the furnace tube.

2. The pipe bank structure according to claim 1, characterized in that: Alternatively, between the first U-shaped furnace tube inlet (3) and the second U-shaped furnace tube inlet (5), the second U-shaped furnace tube inlet (5) is adjacent to the outlet manifold (8), between the first U-shaped furnace tube outlet (4) and the second U-shaped furnace tube outlet (6), the first U-shaped furnace tube outlet (4) is adjacent to the inlet manifold (7), the first U-shaped furnace tube inlet (3) and the second U-shaped furnace tube inlet (5) are generally arranged in an equilateral triangle on the horizontal projection plane, the first U-shaped furnace tube outlet (4) and the second U-shaped furnace tube outlet (6) are arranged in an equilateral triangle on the horizontal projection plane, and the minimum value of the side length c of the equilateral triangle is 2.2 times the outer diameter of the furnace tube.

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