CN216245705U

CN216245705U - Large-scale high-pressure spiral coil pipe waste heat boiler

Info

Publication number: CN216245705U
Application number: CN202122790486.1U
Authority: CN
Inventors: 李勇; 金宇; 武国义; 吴雅玉; 韩锦伟; 王家玮; 鲁鹏涛
Original assignee: Lanzhou LS Heavy Equipment Co Ltd
Current assignee: Lanzhou LS Heavy Equipment Co Ltd
Priority date: 2021-11-15
Filing date: 2021-11-15
Publication date: 2022-04-08
Anticipated expiration: 2031-11-15

Abstract

The utility model relates to a large-scale high-pressure spiral coil pipe waste heat boiler, including establishing the cooling water circulation structure between pipe case and casing, the cooling water circulation structure includes flexible tube sheet and thick tube sheet, constitute the cooling water cavity between these two tube sheets, the flexible tube sheet is the integrated configuration of tube sheet toggle and tube face, can be through the size of adjustment toggle department R, solve flexible tube sheet R department and the great problem of heat exchange tube and flexible tube sheet junction temperature difference stress, make waste heat boiler more adapt to high temperature high pressure operating mode and satisfy the macro-scale demand. In addition, the air inlet pipe orifice of the heat exchange pipe is directly arranged on the pipe plate surface of the flexible pipe plate, and the corundum sleeve is arranged in the air inlet section, so that the temperature difference stress at the welding joint is effectively reduced, and the cracking of the welding position is avoided; the blowdown apparatus is additionally arranged at the bottom of the steam-water separation space, and part of saturated water with higher salt content can be discharged, so that the salt content of the saturated water in the shell is reduced, the scaling on the surface of the heat exchange tube is reduced, and the influence of excessive scaling on the heat transfer efficiency is avoided.

Description

Large-scale high-pressure spiral coil pipe waste heat boiler

Technical Field

The application relates to the technical field of waste heat boilers, in particular to a large-scale high-pressure spiral coil waste heat boiler.

Background

The vertical spiral coil waste heat boiler mainly utilizes high-temperature process gas from a reformer, and boiler water in a boiler shell is heated by the spiral coil to generate medium-pressure steam. Since the process gas temperature from the reformer is up to 1300 ℃, the most critical design of the spent pot is the process gas inlet section.

Shanghai International building Limited company discloses a high-temperature vertical coil waste heat boiler, which is a vertical fire tube type waste heat boiler and comprises a boiler shell part, a tube box part and a coil part. A tube plate cooling water circulation structure is arranged between the boiler shell part and the tube box. The water circulation structure comprises a thick tube plate for connecting the boiler shell part and the tube box, a flexible tube plate is welded on the bottom surface of the thick tube plate, and a cooling cavity is formed between the thick tube plate and the flexible tube plate; the process gas inlet elbow of each coil pipe in the coil pipe part penetrates through the through hole on the thick pipe plate from the boiler shell part, enters the cooling cavity and is welded with the flexible pipe plate, and the pipe orifice is communicated with the converter through the pipe box. The cooling water entering the cooling cavity is uniformly distributed in the cooling cavity under the action of the spoiler of the cooling water, and the cooling water entering the cooling cavity returns to the interior of the pot shell part through the annular gap between the outer wall of the process gas inlet end of the coil pipe and the hole wall of the coil pipe passing hole. However, the above structure has the following drawbacks: saturated steam formed in the cooling cavity can not be discharged in time, so that the pressure and the temperature in the cooling cavity are greatly increased, and the service lives of the process gas inlet bend section and the flexible tube plate are shortened.

In order to solve the problems, the utility model with the patent number ZL201520550402.9 discloses a vertical spiral coil waste heat boiler, which is additionally provided with a saturated steam discharge hole and a component thereof at the top of a thick tube plate, and is used for discharging the saturated steam inside a cooling cavity in time and improving the cooling effect. At present, the device is widely applied to the fields of preparing methanol from coke oven gas, preparing ethylene glycol from crude gas and the like, but the following problems are found in the practical application of the device:

since the structural limitation of the device makes it unable to withstand higher pressure conditions, such as failure, it is urgent to develop a waste heat boiler that can safely operate under the conditions. Specifically, under the above-described high-pressure conditions,

1. in the cooling water circulation structure, the coil pipe is connected with the flexible pipe plate through the horn pipe, the circumferential weld is more, the welding amount is larger, the welding position is easy to crack, and the transition round angle at the flanging part of the flexible pipe plate is smaller, so that the thermal stress caused by the thermal expansion of the heat exchange pipe and the flexible pipe plate can not be effectively absorbed. Due to the structural limitations, the device cannot be applied to working conditions with higher pressure requirements and larger specifications, such as a residual oil POX gas making hydrogen production device (the process gas temperature is about 1300 ℃, and the saturated steam pressure is 11.0 MPa).

2. After the high-temperature process gas exchanges heat with saturated water in the shell through the heat exchange tube, a part of the saturated water is vaporized and then is led out through the steam-water separation element and the steam outlet to enter the next process, the salt concentration of the saturated water which is not vaporized and deposited is higher and higher, and the device is not provided with a pollution discharge device, so that salt accumulated on an evaporation surface cannot be discharged, and the heat transfer is easily affected by scaling on the surface of the heat exchange tube.

Disclosure of Invention

The technical problem that this application will be solved provides a large-scale high pressure spiral coil pipe waste heat boiler to adapt to high temperature high pressure operating mode and satisfy the maximization demand.

In order to solve the problems, the application provides a large-scale high-pressure spiral coil waste heat boiler, which comprises a cooling water circulation structure arranged between a tube box and a shell, wherein the cooling water circulation structure comprises a flexible tube plate and a thick tube plate, a cooling water cavity is formed between the two tube plates, the flexible tube plate comprises a tube plate surface and a tube plate toggle joint arranged at the edge of the tube plate surface, and the radian radius R of the tube plate toggle joint is adjusted according to the thermal stress required to be coped with.

Preferably, the tube sheet toggle has two interfaces that interface with the tube sheet face edge and the inner wall of the tube box cylinder, respectively.

Preferably, the tube sheet toggle has three interfaces that interface with the tube sheet face edge, the tube box end, and the thick tube sheet end, respectively.

Preferably, the waste heat boiler also comprises a heat exchange tube, the gas inlet section of which penetrates through the thick tube plate, the cooling water cavity and the flexible tube plate, the gas inlet pipe orifice of the heat exchange tube is directly arranged on the tube plate surface of the flexible tube plate and is communicated with the hearth, and a corundum sleeve is arranged inside the gas inlet section of the heat exchange tube.

Preferably, the corundum sleeve comprises a large section and a small section, the inner diameter of the large section is larger than that of the small section, the small section is far away from the hearth and embedded into the air inlet section of the heat exchange tube, and the large section is close to the hearth and is arranged outside the air inlet section of the heat exchange tube.

Preferably, the gas inlet pipe orifice of the heat exchange pipe and the pipe plate surface of the flexible pipe plate are welded completely.

Preferably, this waste heat boiler still includes the steam-water separation space that is located its top and establishes the waste fitting discharging of steam-water separation space bottom, waste fitting discharging includes the set ring canal, establishes the horn pipe that the set ring canal upper shed was gone up, establishes the drain on the casing, and the intercommunication the drain with the connecting pipe of pipeline is traded in the set.

Compared with the prior art, the method has the following advantages:

1. the flexible tube plate is designed into a combined structure of the toggle joints of the tube plate and the surface of the tube plate, so that the sizes of the tube box cylinder and the thick tube plate can be reduced, the cost is saved, and meanwhile, the problem of large temperature difference stress at the R position of the flexible tube plate and the joint of the heat exchange tube and the flexible tube plate can be solved by adjusting the size of the R position of the toggle joints of the tube plate, so that the waste heat boiler can be more suitable for high-temperature and high-pressure working conditions and meet the large-scale requirement.

2. The corundum sleeve is additionally arranged at the gas inlet section of the heat exchange tube, so that the heat exchange tube and the welding joint of the heat exchange tube and the flexible tube plate are protected when process gas at about 1300 ℃ enters the tube box, the temperature difference stress at the welding joint is effectively reduced, the cracking of the welding position is avoided, and the capacity of the heat exchange tube for adapting to high-temperature and high-pressure working conditions and meeting large-scale requirements is further enhanced.

3. The blowdown device is additionally arranged at the bottom of the steam-water separation space, and part of saturated water with higher salt content can be discharged, so that the salt content of the saturated water in the shell is reduced, the surface scaling of the heat exchange tube is further reduced, the influence of excessive scaling on the heat transfer efficiency is avoided, and the service life of equipment is prolonged.

Drawings

The following describes embodiments of the present application in further detail with reference to the accompanying drawings.

Fig. 1 is a schematic view of the overall structure of a large-sized high-pressure spiral coil waste heat boiler provided in the embodiment of the present application.

Fig. 2 is two schematic structural views of a flexible tube sheet provided in an embodiment of the present application.

Fig. 3 is a view of two application scenarios of the flexible tube sheet shown in fig. 2.

Fig. 4 is a detailed view of the connection between the flexible tube plate and the heat exchange tube provided in the embodiment of the present application.

Fig. 5 is a schematic structural diagram of a sewage draining device according to an embodiment of the present application.

In the figure: 1-tube box, 11-corundum sleeve, 12-flexible tube plate, 13-thick tube plate, 14-water supply tube, 121-tube plate surface and 122-tube plate toggle joint; 2, a shell; 3, heat exchange tube; 4-sewage draining device, 41-horn pipe, 42-collecting ring pipe, 43-connecting pipe; 5-a steam-water separation element; 6-steam outlet; 7-central cylinder.

Detailed Description

Referring to fig. 1, the embodiment of the present application provides a large-scale high-pressure spiral coil waste heat boiler, which mainly includes a tube box 1, a shell 2, a cooling water circulation structure disposed between the tube box 1 and the shell 2, a heat exchange tube bundle disposed inside the shell 2, a steam-water separation space disposed at the top of the shell 2, and a steam-water separation element 5 disposed in the space. The heat exchange tubes 3 in the heat exchange tube bundle penetrate through the tube plates, are spirally wound on the central barrel 7 in multiple layers, are spirally wound from the outer layer, are wound from the inner layer to the lower layer through the top connecting tube after being wound from the upper layer, and are finally led out from the steam outlet 6. The cooling water circulation structure comprises a flexible tube plate 12 and a thick tube plate 13, a cooling water cavity is formed between the two tube plates, and a water supply tube 14 supplies cooling water to the cooling water cavity.

Referring to fig. 2 and 3, in the present application, the flexible tube sheet 12 is a combination structure of toggle joints and tube sheet faces, including the tube sheet face 121 and the toggle joints 122 arranged at the edge of the tube sheet face 121, and the arc radius R of the toggle joints 122 is adjusted according to the magnitude of thermal stress to be handled, so that the thermal stress of the flexible tube sheet 12 caused by the thermal expansion of the gas inlet section of the heat exchange tube 3 and the heat of the flexible tube sheet 12 can be effectively reduced, and the risk of cracking of the flexible tube sheet 12 is reduced.

In practical applications, the tube sheet face 121 is formed by machining a plate, and the tube sheet toggle 122 may be a forged piece or a stamped plate. The tubesheet wrist 122 may be of two configurations:

the first method comprises the following steps: the tube sheet toggle 122 is generally bowl-shaped and has two interfaces that interface (weld) with the edge of the tube sheet face 121 and the inner wall of the tube box body 15. In this way, the toggle joint 122 of the tube plate can be a forge piece or can be formed by punching a plate; the flexible tube plate 12 is directly welded with the inner wall of the tube box body 15, and the welding is simple and convenient.

And the second method comprises the following steps: the tube sheet toggle 122 has three interfaces that interface (weld) with equal thickness at the edge of the tube sheet face 121, the end of the tube box body 15, and the end of the thick tube sheet 13, respectively. Specifically, the tube plate toggle 122 includes a cylinder connecting section (in butt joint with the tube box cylinder 15), a thick tube plate connecting section (in butt joint with the thick tube plate 13), a transition section and a tube plate surface connecting section (in butt joint with the tube plate surface 121), and the cylinder connecting section and the tube plate surface connecting section are connected into an integrated structure (a forged piece) through a transition section arc transition.

Referring to fig. 3, the gas inlet section of the heat exchange tube 3 passes through the thick tube plate 13, the cooling water cavity and the flexible tube plate 12, and the gas inlet pipe orifice of the heat exchange tube 3 is directly arranged on the tube plate surface 121 of the flexible tube plate 12 and is communicated with the furnace. Referring to fig. 4, a full penetration welding joint is adopted between the gas inlet pipe opening of the heat exchange pipe 3 and the pipe plate surface 121 of the flexible pipe plate 12, single-side welding and double-side forming are carried out, so that the heat exchange pipe 2 and the flexible pipe plate 12 are welded completely, and the back surface of the pipe plate is formed well.

The corundum sleeve 11 is arranged in the gas inlet section of the heat exchange tube 3, so that the temperature difference stress at the welding joint is effectively reduced. Specifically, the corundum sleeve 11 can be arranged in a segmented manner, and comprises a large section and a small section, wherein the inner diameter of the large section is larger than that of the small section, the small section is far away from the hearth and is embedded into the air inlet section of the heat exchange tube 3, and the large section is close to the hearth and is arranged outside the air inlet section of the heat exchange tube 3.

In practical application, the working process of the waste heat boiler is as follows: the water supply pipe 14 provides cooling water for the cooling water cavity, cools the flexible tube plate 12, and then flows into the shell 2 through a gap between the heat exchange pipe 3 and the thick tube plate 13 in a unidirectional flow manner; heat exchange is carried out with the heat exchange tubes 3 in the shell 2, and after heat exchange, a part of saturated water forms a steam-water mixture and flows upwards through gaps among the heat exchange tubes 3. The generated steam-water mixture is subjected to steam-water separation through the steam-water separation element 5, the separated saturated steam is discharged from the steam outlet 6, and the separated saturated water flows into the shell 2 and exchanges heat with the heat exchange tube 3 again. Part of the saturated water which is not vaporized after heat exchange enters the bottom of the shell 2 through the central cylinder 7 to circularly exchange heat with the heat exchange tubes 3.

In the working process, after the high-temperature process gas exchanges heat with the saturated water in the shell 2 through the heat exchange tube 3, a part of the saturated water is vaporized and enters the next process through the steam outlet 6, the salt concentration of the saturated water which is not vaporized and deposited is higher and higher, especially the concentration of the bottom of the steam-water separation space is highest, and in order to not influence the heat transfer efficiency, a pollution discharge device 4 is arranged at the position (the bottom of the steam-water separation space) with the highest salt concentration in the shell 2.

Referring to fig. 5, the sewage draining device 4 of the present application specifically includes a collecting loop pipe 42, a flared pipe 41 uniformly distributed on the collecting loop pipe 42 and having an opening, a sewage draining outlet disposed on the housing 2, and a connecting pipe 43 for connecting the sewage draining outlet and the collecting loop pipe 42. Part of the saturated water with higher salt content can be discharged through the sewage discharging device 4, so that the salt content of the saturated water in the shell is reduced.

The technical solutions provided by the present application are described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the structure and the core concept of the present application. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.

Claims

1. The large-scale high-pressure spiral coil waste heat boiler comprises a cooling water circulation structure arranged between a tube box (1) and a shell (2), wherein the cooling water circulation structure comprises a flexible tube plate (12) and a thick tube plate (13), and a cooling water cavity is formed between the two tube plates, and is characterized in that the flexible tube plate (12) comprises a tube plate surface (121) and a tube plate toggle joint (122) arranged at the edge of the tube plate surface (121), and the radian radius R of the tube plate toggle joint (122) is adjusted according to the magnitude of thermal stress to be dealt with.

2. Waste heat boiler according to claim 1, characterized in that the tube sheet toggle (122) has two interfaces, which interface with the edge of the tube sheet face (121) and the inner wall of the tube box cylinder (15), respectively.

3. Waste heat boiler according to claim 1, characterized in that the tube sheet toggle (122) has three interfaces, respectively interfacing with the edge of the tube sheet face (121), the end of the tube box cylinder (15) and the end of the thick tube sheet (13).

4. The waste heat boiler of claim 1, further comprising a heat exchange tube (3) having an air inlet section penetrating through the thick tube plate (13), the cooling water chamber and the flexible tube plate (12), wherein an air inlet pipe opening of the heat exchange tube (3) is directly formed on a tube plate surface (121) of the flexible tube plate (12) and is communicated with the furnace, and a corundum sleeve (11) is arranged inside the air inlet section of the heat exchange tube (3).

5. Waste heat boiler according to claim 4, characterized in that the corundum sleeve (11) comprises a large section and a small section, the inner diameter of the large section is larger than that of the small section, the small section is far away from the furnace and embedded in the gas inlet section of the heat exchange tube (3), and the large section is close to the furnace and arranged outside the gas inlet section of the heat exchange tube (3).

6. Waste heat boiler according to claim 4, wherein the inlet nozzle of the heat exchange tube (3) is welded through to the tube plate surface (121) of the flexible tube plate (12).

7. Waste heat boiler according to claim 1, further comprising a steam-water separation space at the top of the waste heat boiler and a drain (4) arranged at the bottom of the steam-water separation space, wherein the drain comprises a collecting loop (42), a flared tube (41) arranged on the collecting loop (42) and having an opening, a drain outlet arranged on the housing (2), and a connecting tube (43) connecting the drain outlet and the collecting loop (42).