Radiant pipe system structure and natural gas converter comprising same

Abstract

The utility model discloses a radiant tube system structure and a natural gas converter comprising the radiant tube system structure. The radiant tube system structure comprises an inlet gas collection header pipe, a gas transmission header pipe and a plurality of groups of parallel radiant tube arrays, wherein each group of parallel radiant tube array comprises an inlet distribution tube, an outlet collecting tube and a plurality of paths of parallel radiant tubes; each parallel radiant tube comprises an inlet pigtail tube, a conversion tube and an outlet connecting tube which are sequentially connected from top to bottom, the two parallel radiant tubes are symmetrically distributed on the two sides of the inlet distribution tube, the inlet pigtail tubes are horizontally and vertically connected with the axis of the inlet distribution tube, and the outlet connecting tubes at the outlets of the parallel radiant tubes are connected with an outlet collecting tube. And a group of connected radiant tube arrangement is formed. According to the utility model, the high-temperature expansion thermal stress of the whole pipe system during operation can be effectively reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of natural gas conversion, and mainly relates to a furnace pipe system structure of a radiation section of a natural gas conversion furnace. Background Art

[0002] The natural gas reformer is the main equipment of petrochemical plants (hydrogen production, synthetic ammonia, methanol, etc.). It mainly uses natural gas, oilfield gas and other raw materials to undergo a conversion reaction under high temperature and a certain pressure (such as 4Mpa) through the action of a catalyst to produce a conversion gas with H2 and CO as the main components, which serves as the raw gas for downstream products.

[0003] The furnace pipe system of the radiation section of the reformer is mainly composed of the inlet gas collecting main pipe, inlet distribution pipe, inlet pigtail pipe, reformer pipe, outlet connecting pipe and outlet manifold. The pipe system is in a high temperature state during operation. The inlet raw gas temperature of the pipe system is usually between 475-650℃. The reformer tube is directly heated by the flame in the furnace. The wall temperature of the reformer tube can reach up to 1000℃. The reforming reaction is carried out in the reformer tube. The outlet reforming gas temperature is usually between 750-930℃. The pipe system is under high temperature and pressure during operation, and the expansion displacement of each component that needs to be coordinated is large, and the stress of the pipe system is complex. The overall structural characteristics of the currently popular pipe system are that the inlet distribution pipe and the reformer use flexible pigtail pipes to coordinate the thermal expansion of the reformer tubes. The outlet connecting pipe uses flexible pigtail pipes + hot wall manifolds to connect to the outlet cold wall manifold, and also uses hot and cold wall connecting pipes to directly connect to the outlet cold wall manifold.

[0004] The investment in the converter is large, and its long-term operation requires continuous improvement of the design and use of optimizable content. Measures such as more coordinated deformation, smaller temperature differences, and more uniform force should be taken to avoid the impact of additional deformation and stress on high-temperature components. Utility Model Content

[0005] The purpose of the utility model is to provide an improved radiation pipe system structure of a natural gas reformer in view of the defects of the prior art, which can effectively reduce the thermal stress caused by thermal expansion of the radiation pipe system during actual operation, ensure the reliability and safety of the overall pipe system, and provide a natural gas reformer including the above-mentioned radiation pipe system structure.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a natural gas reformer radiation pipe system structure, including: an inlet gas collecting main pipe, a gas transmission main pipe and an array of parallel radiation tubes;

[0007] Each group of parallel radiation tubes includes an inlet distribution tube, an outlet collection tube and multiple parallel radiation tubes; each parallel radiation tube includes an inlet pigtail tube, a conversion tube and an outlet connecting tube connected in sequence from top to bottom, and two parallel radiation tubes are symmetrically distributed on both sides of the inlet distribution tube, the inlet pigtail tube is horizontally connected to the axis of the inlet distribution tube vertically, and the outlet connecting tube of the parallel radiation tube outlet is connected to the outlet collection tube to form a group of parallel radiation tubes;

[0008] The plurality of parallel radiant tubes are arranged and connected in parallel, the plurality of inlet distribution pipes at the inlet are connected to the inlet gas collecting main pipe, and the outlet collecting pipe at the outlet is connected to the gas transmission main pipe, thus forming a parallel radiant tube array.

[0009] Furthermore, the outlet manifold is a hot wall manifold or a cold wall manifold.

[0010] Furthermore, when the outlet collecting pipe is a hot wall collecting pipe, the outlet connecting pipe is an outlet pigtail pipe, the number of inlet distribution pipes and hot wall collecting pipes in each group of parallel radiation tubes is the same, and the outlet pigtail pipes at the outlets of the two parallel radiation tubes are symmetrically distributed on both sides of the hot wall collecting pipe, and the outlet pigtail pipes are horizontally connected to the axis of the hot wall collecting pipe vertically.

[0011] Furthermore, when the outlet collecting pipe is a cold wall collecting pipe, the outlet connecting pipe is a rigid straight-connected pipe, the number of cold wall collecting pipes is twice the number of inlet distribution pipes, and in the two symmetrically distributed parallel radiation tubes, the rigid straight-connected pipe at the outlet of one side of the parallel radiation tubes is connected to a cold wall collecting pipe.

[0012] Furthermore, cooling fins are provided on the cold wall collecting pipe side close to the conversion pipe or on the rigid straight-connected pipe or the gas transmission main pipe. The cooling fins are arranged spirally, annularly or axially along the cold wall collecting pipe, and the cooling fins are comb-tooth or corrugated plate structures.

[0013] Furthermore, a conical diffuser or a basket-type gas distributor is provided at the end of the inner process gas conduit of the rigid straight-connecting pipe.

[0014] Furthermore, the length of the rigid straight-connecting pipe is 600 to 1000 mm.

[0015] Furthermore, a saddle support is provided at the bottom of the cold wall manifold, and a stress release groove is provided at the connection between the web of the saddle support and the manifold.

[0016] A natural gas reformer comprises the above-mentioned radiation pipe system structure.

[0017] Furthermore, expansion holes 50 to 80 mm larger than the outer diameter of the conversion tube are provided at the positions where the conversion tube passes through the furnace bottom plate and the furnace top plate of the conversion furnace; a positioning ring 2 to 8 mm larger than the outer diameter of the conversion tube is provided above the furnace top through hole; and an opening is provided at the top of the flue at the bottom of the radiation section of the conversion furnace.

[0018] The beneficial effect of the utility model is that the radiation pipe system structural solution can effectively reduce the high-temperature expansion thermal stress of the entire pipe system during operation.

[0019] (1) The structural symmetry of the inlet pigtail pipe and the inlet distribution pipe on both sides horizontally connects to balance the force of the conversion pipe during vertical expansion and displacement;

[0020] (2) An expansion hole 50 to 80 mm larger than the outer diameter of the conversion tube is opened at the position where the conversion tube passes through the furnace bottom, so that the conversion tube will not be hindered by the furnace bottom plate when it expands and moves with the cold wall manifold. On the basis of effectively ensuring the sealing of the furnace bottom plate, the thermal stress of the joint of the conversion tube and the cold wall manifold is reduced;

[0021] (3) Increase the heat dissipation of the upper part of the cold wall manifold by adding a heat dissipation fin structure on the upper part of the cold wall manifold. Adding a conical diffuser or a basket-type gas distributor at the process inlet of the cold wall manifold can not only prevent high-speed gas from directly scouring the castable, but also make the temperature of the upper and lower sides of the cold wall manifold close, reduce the temperature difference stress caused by the temperature difference between the upper and lower surfaces, avoid the "thermal arch" phenomenon of the cold wall manifold, and also reduce the impact of the deformation of the cold wall manifold on the uneven stress of the upper pipe system;

[0022] (4) On the saddle supports of the cold wall manifold and the gas main, a stress relief groove can be opened in the middle of the web, which can also effectively reduce the thermal stress of the cold wall pipe;

[0023] (5) If the rigid straight-connecting pipe is too short, it will lead to a large temperature gradient in the conversion tube, large temperature stress, and serious cold wall manifold arch phenomenon; if the rigid straight-connecting pipe is too long, it will lead to a high furnace bottom and increase the construction cost. According to the analysis of temperature field and stress field, the appropriate length of the cold and hot wall connecting pipe can be selected;

[0024] (6) The top of the converter tube is pre-biased during installation, so that the converter tube is in a slightly tilted state during installation, and can be restored to a vertical state under operating conditions, reducing the additional stress caused by the displacement difference between the converter tube and the cold wall manifold during operation; the converter tube is in a vertical state during operation (when the hanging point is in the normal position, the converter tube is pre-biased during installation, and when the converter tube is installed in the designed position, the hanging point is pre-biased). In order to make the converter tube temperature more uniform, a small number of openings are added to the top of the flue at the bottom of the radiation section to facilitate fine-tuning when necessary to make the flue gas flow field outside the converter tube more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the front view of the radiation tube system structure of Example 1.

[0026] Figure 2 It is a side view of the radiation tube system structure of Example 1.

[0027] Figure 3It is a schematic diagram of the structure of the cold wall collecting pipe, the heat dissipation fins of the gas transmission main pipe, the support stress release groove and the basket-type gas distributor of Example 1.

[0028] Figure 4 This is a diagram of the spiral arrangement of the cooling fins of the cold wall manifold and the gas main pipe in Example 1.

[0029] Figure 5 The spiral grooved structure of the cooling fins of the cold wall collecting pipe and the gas main pipe in the first embodiment.

[0030] Figure 6 This is the front view of the conversion tube in the pre-biased state of Example 2.

[0031] Figure 7 This is a top view of the conversion tube of Example 2 passing through the furnace bottom plate.

[0032] Figure 8 It is a schematic diagram of the connection between the outlet pigtail pipe and the hot wall manifold in Example 3.

[0033] Reference numerals:

[0034] 1-inlet gas collecting main pipe; 2-inlet distribution pipe; 3-inlet pigtail pipe; 4-conversion pipe; 5-cold wall collecting pipe; 6-gas transmission main pipe; 7-exit pigtail pipe; 8-hot wall collecting pipe; 9-furnace top plate; 10-furnace bottom plate; 11-annular heat dissipation fins (on rigid direct connection pipe); 12-annular heat dissipation fins (on cold wall collecting pipe or gas transmission main pipe); 13-spiral heat dissipation fins; 14-stress relief groove; 15-basket type gas distributor; 16-rigid direct connection pipe; 17-positioning ring DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0036] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0037] Example 1

[0038] like Figure 1 and 2 As shown, a reformer radiation pipe system structure includes: an inlet gas collecting main pipe 1, a gas transmission main pipe 6 and a plurality of parallel radiation tubes. Each parallel radiation tube arrangement includes an inlet distribution pipe 2, a cold wall collecting pipe 5 and multiple parallel radiation tubes.

[0039] Each parallel radiation tube includes an inlet pigtail tube 3, a conversion tube 4 and a rigid straight-connected tube 16 which are connected in sequence from top to bottom. The two parallel radiation tubes are symmetrically distributed on both sides of the inlet distribution tube. The inlet pigtail tube is horizontally connected to the axis of the inlet distribution tube vertically. The rigid straight-connected tubes at the outlets of the parallel radiation tubes are connected to the cold wall collecting tubes to form a group of parallel radiation tubes. The number of cold wall collecting tubes is twice that of the inlet distribution tubes. In the two symmetrically distributed parallel radiation tubes, the rigid straight-connected tube at the outlet of one side of the parallel radiation tubes is connected to a cold wall collecting tube.

[0040] The plurality of parallel radiant tubes are arranged in parallel and connected, the plurality of inlet distribution pipes at the inlet are connected to the inlet gas collecting main pipe, and the outlet cold wall collecting pipe at the outlet is connected to the gas transmission main pipe, forming a parallel radiant tube array.

[0041] like Figure 3 and 4 As shown, a basket-type gas distributor 15 can be provided at the end of the process gas conduit on the inner side of the rigid straight-connected pipe. The cooling fins are arranged on the side of the cold wall manifold close to the conversion tube; the cooling fins can be arranged spirally, circumferentially or axially along the cold manifold, and the cooling fins are comb-tooth or corrugated plate structures. The cooling fins can be made of the same material as the cold manifold, or other materials with good thermal conductivity. Reference numeral 11 is an annular cooling fin on the rigid straight-connected pipe, 12 is an annular cooling fin on the cold wall manifold or the gas main, and 13 is a spiral cooling fin.

[0042] like Figure 3 As shown, on the saddle support at the bottom of the cold wall manifold, a stress relief groove 14 can be opened at the connection between the web and the manifold. Figure 5 It is a spiral groove structure of the cooling fins of the cold wall manifold and the gas main pipe. The heat sink is a comb-tooth or corrugated plate structure, and the groove spacing and depth are determined according to the heat dissipation requirements.

[0043] The rigid straight-connecting pipe is preferably 600 to 1000 mm long.

[0044] Example 2

[0045] A natural gas reformer comprising the radiation pipe system structure of Example 1. Figure 6 As shown, when the conversion tube and the cold wall manifold are connected by a rigid straight pipe, a hole larger than the outer diameter of the conversion tube by 50 to 80 mm is provided at the position where the conversion tube passes through the furnace bottom plate 9 and the furnace top plate 10. Figure 7As shown, the conversion tube is eccentric to the side of the furnace bottom or furnace top through hole away from the operation displacement direction. A positioning ring 17 is set on the furnace top through hole, which is only 2 to 8 mm larger than the outer diameter of the conversion tube. After the conversion tube is welded to the upper and lower parts, the positioning ring is used to offset and position the conversion tube according to the displacement direction and expansion amount during the operation of the cold wall manifold. The expansion amount of each point of the conversion tube is different, and the far end is the largest. The aperture and hole spacing can be considered to be changed one by one or step by step to minimize the opening area.

[0046] The top hanging point of the conversion tube is pre-shifted according to the displacement direction and expansion amount during the operation of the cold wall manifold.

[0047] Example 3

[0048] A reformer radiation tube system structure includes: an inlet gas collecting main pipe 1, a gas transmission main pipe 6 and a plurality of parallel radiation tubes. Each group of parallel radiation tubes includes an inlet distribution pipe 2, a hot wall collection pipe 8 and multiple parallel radiation tubes. Each parallel radiation tube includes an inlet pigtail pipe 3, a reformer pipe 4 and an outlet pigtail pipe 7 connected in sequence from top to bottom. The two parallel radiation tubes are symmetrically distributed on both sides of the inlet distribution pipe, and the inlet pigtail pipe is horizontally connected to the axis of the inlet distribution pipe vertically. The outlet pigtail pipes at the outlets of the two parallel radiation tubes are symmetrically distributed on both sides of the hot wall collection pipe, and the outlet pigtail pipe is horizontally connected to the axis of the hot wall collection pipe vertically (such as Figure 8 As shown), a group of radiant tubes are formed.

[0049] The plurality of parallel radiant tubes are arranged and connected in parallel, the plurality of inlet distribution pipes at the inlet are connected to the inlet gas collecting main pipe, and the outlet collecting pipe at the outlet is connected to the gas transmission main pipe, thus forming a parallel radiant tube array.

[0050] The above is a further detailed description of the utility model, which should not be regarded as a limitation on the specific implementation of the utility model. For ordinary technicians in the technical field to which the utility model belongs, simple deduction or replacement without departing from the concept of the utility model is within the protection scope of the utility model.

Claims

1. A natural gas reformer radiation pipe system structure, characterized in that include: Inlet gas collecting main pipe, gas transmission main pipe and array parallel radiant tube arrangement; Each group of parallel radiation tubes includes an inlet distribution tube, an outlet collection tube and multiple parallel radiation tubes; each parallel radiation tube includes an inlet pigtail tube, a conversion tube and an outlet connecting tube connected in sequence from top to bottom, and two parallel radiation tubes are symmetrically distributed on both sides of the inlet distribution tube, the inlet pigtail tube is horizontally connected to the axis of the inlet distribution tube vertically, and the outlet connecting tube of the parallel radiation tube outlet is connected to the outlet collection tube to form a group of parallel radiation tubes; The plurality of parallel radiant tubes are arranged in parallel and connected, the plurality of inlet distribution pipes at the inlet are connected to the inlet gas collecting main pipe, and the outlet collecting pipe at the outlet is connected to the gas transmission main pipe, forming a parallel radiant tube array; The outlet manifold is a cold wall manifold; When the outlet manifold is a cold wall manifold, the outlet connecting pipe is a rigid straight-connected pipe, the number of cold wall manifolds is twice that of the inlet distribution pipes, and in the two symmetrically distributed parallel radiant tubes, the rigid straight-connected pipe at the outlet of one side of the parallel radiant tubes is connected to a cold wall manifold; The cold wall manifold is provided with heat dissipation fins on the side of the conversion tube or the rigid straight-connected pipe or the gas main pipe. The heat dissipation fins are arranged spirally, annularly or axially along the cold wall manifold, and the heat dissipation fins are comb-tooth or corrugated plate structures.

2. The radiation pipe system structure of the natural gas reformer according to claim 1 is characterized in that: The inner process gas conduit end of the rigid straight-connected pipe is provided with a conical diffuser or a basket-type gas distributor.

3. The radiation pipe system structure of the natural gas reformer according to claim 1 is characterized in that: The length of the rigid straight-connecting pipe is 600-1000 mm.

4. The radiation pipe system structure of the natural gas reformer according to claim 1 is characterized in that: A saddle support is arranged at the bottom of the cold wall collecting pipe, and a stress release groove is arranged at the connection between the web of the saddle support and the collecting pipe.

5. A natural gas reformer, characterized in that: The invention comprises the radiation tube system structure as described in any one of claims 1 to 4.

6. The natural gas reformer according to claim 5, characterized in that: The furnace bottom plate and the furnace top plate of the converter are provided with expansion holes 50 to 80 mm larger than the outer diameter of the converter tube at the position where the converter tube passes through; a positioning ring 2 to 8 mm larger than the outer diameter of the converter tube is arranged above the furnace top through hole; and an opening is arranged at the top of the flue at the bottom of the radiation section of the converter.

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