Medium-pressure steam generator

Abstract

The utility model belongs to a medium-pressure steam generator. Comprising a tube box and a barrel, a tube bundle is arranged between one side of the tube box and one side of the barrel, a plurality of heat exchange tubes are arranged on the end face of the tube bundle, a waste heat source inlet and a waste heat source outlet are formed in the upper portion and the lower portion of the tube box respectively, and a partition plate is arranged between the inner wall of the tube box and the middle of the end face of the tube bundle. A condensate inlet is formed in the other side of the cylinder body, and a heating pipe unit for preheating and heating condensate is arranged in the cylinder body corresponding to the lower part of the condensate inlet; according to the mode, the temperature difference between the tube pass and the shell pass can be reduced, so that the service life of the medium-pressure steam generator is prolonged, and the replacement and maintenance period of the heat exchange tube is prolonged to about three years from about half a year in the prior art.

Description

TECHNICAL FIELD

[0001] The utility model belongs to petrochemical equipment technical field, concretely is a kind of medium-pressure steam generator. BACKGROUND

[0002] Medium-pressure steam generator is also called medium-pressure waste boiler, commonly used in chemical industry, steel, pharmaceutical, machinery, light industry, oil refining and many other fields. Domestic chemical enterprises generally use medium-pressure steam generator for waste heat recovery, which plays an important role in heat exchange and transfer in the whole production process, not only effectively reduces air pollution, but also efficiently utilizes waste heat, so as to achieve the purpose of reducing energy consumption cost and improving enterprise economic benefit. Medium-pressure waste boiler mainly adopts shell-and-tube structure, which is a typical type of heat exchanger, usually composed of tube bundle, tube plate, cylinder and end cover. This heat exchanger has the advantages of strong durability, wide material, strong adaptability and high reliability, and dominates in heat exchange equipment application. Further, the failure of medium-pressure waste boiler leading to shutdown is mainly caused by leakage, and many materials in heat exchanger have the characteristics of flammable, explosive and toxic. Once leakage occurs, it may affect product quality and yield, or even cause equipment damage and personnel casualties. Research shows that the leakage of shell-and-tube heat exchanger mainly includes heat exchange tube leakage and tube plate leakage, and excessive thermal stress is the main reason for medium-pressure waste boiler leakage, that is, the large temperature difference between tube and shell causes heat exchange tube cracking under the action of temperature difference stress, thereby causing medium-pressure waste boiler leakage. Based on the above reasons, medium-pressure steam generator generally leaks after running for about half a year, resulting in system shutdown for maintenance, and the heat exchange tube needs to be replaced and maintained, which has the defects of large maintenance engineering quantity and high maintenance cost. CONTENT OF THE UTILITY MODEL

[0003] In order to make up for the above shortcomings, the utility model provides a medium-pressure steam generator to solve the technical problems existing in the prior art.

[0004] The utility model solves the technical problems by adopting the following technical scheme:

[0005] A medium-pressure steam generator, the medium-pressure steam generator includes a pipe box, a cylinder, a tube bundle between one side of the pipe box and the cylinder, a plurality of heat exchange tubes on the end face of the tube bundle, a waste heat source inlet and a waste heat source outlet respectively arranged on the upper part and the lower part of the pipe box, a partition plate arranged on the inner wall of the pipe box and the end face of the tube bundle, a steam outlet arranged on the top of the cylinder, a condensate inlet arranged on the other side of the cylinder, and a warm pipe unit for preheating and heating the condensate arranged in the cylinder corresponding to the condensate inlet.

[0006] The beneficial effects of this utility model are as follows: by setting a warming tube unit, the condensate inside the shell can be heated, and the heat exchange tubes can be warmed at the same time as the condensate is heated; the above method can reduce the temperature difference between the tube side and the shell side, thereby extending the service life of the medium-pressure steam generator and extending the heat exchange tube replacement and maintenance cycle from the traditional six months to about three years.

[0007] Preferably, the heating pipe unit includes at least a heat source inlet pipe disposed at the lower part of the cylinder, and the heat source inlet pipe is connected to a heating pipe disposed inside the cylinder and disposed parallel to the heat exchange pipe.

[0008] Preferably, the heating tube is located in the lower middle part of the cylinder, and there are three heating tubes, one of which is located in the middle of the cylinder, and the other two heating tubes are located on both sides of the cylinder.

[0009] Preferably, the heating tube has a cap at its end and steam holes are evenly distributed on its surface.

[0010] Preferably, the end of the heat source inlet pipe is provided with a flange for easy connection to the steam network.

[0011] Preferably, the corresponding heat source inlet pipe inside the cylinder is provided with several support rods for fixing the heat source inlet pipe. One end of the support rod is connected to the outer wall of the heat source inlet pipe, and the other end of the support rod is connected to the inner wall of the cylinder.

[0012] Preferably, side support platforms are respectively provided on the inner wall of the cylinder at the lower part of the heating tubes on both sides of the cylinder. The top of the side support platform is fixedly connected to the outer circumference of the heating tube by U-bolts; the bottom of the side support platform is provided with reinforcing ribs connected to the inner wall of the cylinder.

[0013] Preferably, the overlap ratio between the heating tube and the heat exchange tube is 1 to 2:3.

[0014] Preferably, the tube bundle and the heat exchange tube are connected by hydraulic expansion joint.

[0015] The medium-pressure steam generator prepared according to the technical scheme can realize the reduction of the temperature difference between the tube and shell by arranging the warm pipe unit, thereby avoiding the defect that the medium-pressure waste boiler leaks due to the cracking of the heat exchange pipe, the warm pipe unit can heat the condensate to realize the purpose of warming the heat exchange pipe, the warm pipe unit can adopt the forms of electric heating, steam heating or heat conducting oil heating, and the purpose is to reduce the temperature difference between the tube and shell; the multiple evenly arranged heating pipes can uniformly heat the shell, thereby reducing the temperature difference between the tube and shell; further, the overlapping ratio between the heating pipe and the heat exchange pipe is 1-2:3, the arrangement can realize the purpose of fully heating the condensate between the heat exchange pipes; the preferred steam directly enters the shell to heat, the arrangement can directly heat the condensate to improve the heat efficiency; the heating pipe is prone to vibration when directly heated by steam, therefore, the utility model arranges the supporting rod and the side support platform to firmly fix the warm pipe unit, so that the device can be operated for a long time; the utility model has the advantages of reasonable structure, energy saving and consumption reduction, avoiding the cracking of the heat exchange pipe due to the temperature difference stress, thereby avoiding the defect that the medium-pressure waste boiler leaks, and reducing the maintenance workload and cost. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creating labor.

[0017] Fig. 1 It is the structural schematic diagram of the utility model.

[0018] Fig. 2 It is the structural schematic diagram of the warm pipe unit inside the cylinder of the utility model.

[0019] Fig. 3 It is the structural schematic diagram of the heating pipe of the utility model.

[0020] In the drawing: 1, pipe box;2, cylinder;3, tube bundle;4, heat exchange pipe;5, waste heat source inlet;6, waste heat source outlet;7, partition;8, steam outlet;9, condensate inlet;10, heat source inlet pipeline;11, heating pipe;12, pipe cap;13, steam hole;14, flange;15, supporting rod;16, side support platform;17, U-shaped bolt;18, reinforcing rib. DETAILED DESCRIPTION

[0021] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Figs. 1-3 Further detailed description is made to the present application, and the present application is a medium-pressure steam generator. The medium-pressure steam generator comprises a tube box 1, a cylinder 2, a tube bundle 3 arranged between one side of the tube box 1 and the cylinder 2, a plurality of heat exchange tubes 4 arranged on an end face of the tube bundle 3, a waste heat source inlet 5 and a waste heat source outlet 6 arranged at upper and lower portions of the tube box 1 respectively, a partition plate 7 arranged at a middle portion of an inner wall of the tube box 1 and an end face of the tube bundle 3, a steam outlet 8 arranged at a top portion of the cylinder 2, a condensate inlet 9 arranged at another side of the cylinder 2, and a warm tube unit arranged in an inner portion of the cylinder 2 corresponding to a lower portion of the condensate inlet 9 and used for preheating and heating the condensate. The warm tube unit in the present application is used for heating the condensate in the shell side of the present application, so as to reduce the temperature difference between the condensate in the cylinder 2 and the heat source in the heat exchange tube 4, thereby achieving the purpose of protecting the heat exchange tube 4. The warm tube unit in the present application is used for preheating and heating the condensate, and based on this, conventional forms such as electric heating, steam heating or heat conducting oil heating can be adopted.

[0023] Further, the warm tube unit at least comprises a heat source inlet pipeline 10 arranged at a lower portion of the cylinder 2, and the heat source inlet pipeline 10 is in communication with a heating tube 11 arranged in an inner portion of the cylinder 2 and parallel to the heat exchange tube 4. Through the above arrangement, the installation of the heating tube 11 can be facilitated, and effective heating around the heat exchange tube 4 can be realized, so as to warm the heat exchange tube 4 and reduce the temperature difference between the condensate and the heat source in the heat exchange tube 4.

[0024] Further, the heating tube 11 is arranged at a middle lower portion of the cylinder 2, and the heating tube 11 is three in number. One of the heating tubes 11 is arranged at a middle position of the cylinder 2, and the other two heating tubes 11 are arranged at two sides of the cylinder 2. Through the above arrangement, the three heating tubes 11 can be uniformly arranged in the inner portion of the cylinder 2. This arrangement not only can uniformly heat the condensate to provide the efficiency of generating steam, but also can uniformly heat the condensate, so as to keep the temperature difference between the condensate in the cylinder 2 and the heat source in the heat exchange tube 4 substantially consistent, thereby achieving the purpose of protecting the heat exchange tube 4.

[0025] Further, the end of the heating pipe 11 is provided with a pipe cap 12, and the surface of the heating pipe 11 is uniformly provided with steam holes 13. The utility model adopts the steam to heat the condensate, and more preferably adopts the steam directly into the condensate to heat, which can effectively improve the heating efficiency; meanwhile, the utility model is mainly used for producing steam, and through the above-mentioned heating mode, the characteristics of convenient pipe arrangement and energy saving can be achieved.

[0026] Further, the end of the heat source inlet pipeline 10 is provided with a flange plate 14 connected with the steam pipe network. The flange plate 14 can realize convenient connection.

[0027] Further, a plurality of supporting rods 15 for fixing the heat source inlet pipeline 10 are arranged on the corresponding heat source inlet pipeline 10 in the cylinder body 2, one end of the supporting rod 15 is connected with the outer wall of the heat source inlet pipeline 10, and the other end of the supporting rod 15 is connected with the inner wall of the cylinder body 2. The above-mentioned arrangement can firmly fix the heat source inlet pipeline 10.

[0028] Further, the lower part of the heating pipe 11 on both sides of the cylinder body 2 is respectively provided with a side bracket platform 16 on the corresponding inner wall of the cylinder body 2, the top of the side bracket platform 16 is fixedly connected with the outer circumference of the heating pipe 11 through a U-shaped bolt 17, and the bottom of the side bracket platform 16 is provided with a reinforcing rib 18 connected with the inner wall of the cylinder body 2. The above-mentioned arrangement can firmly fix the heating pipe 11 on both sides of the cylinder body 2, especially in the start-up stage of the steam and the process of the steam entering the cylinder body 2, vibration will inevitably occur, and the above-mentioned fixing arrangement can effectively improve the firmness between the warm pipe unit and the cylinder body 2, thereby prolonging the service life of the utility model.

[0029] Further, the overlapping ratio between the heating pipe 11 and the heat exchange pipe 4 is 1-2:3. By limiting the overlapping ratio between the heating pipe 11 and the heat exchange pipe 4, the heating pipe 11 can better heat the condensate around the heat exchange pipe 4, so as to improve the warm pipe effect.

[0030] Further, the pipe bundle 3 and the heat exchange pipe 4 are connected through hydraulic expansion. The utility model adopts the hydraulic expansion connection mode between the pipe bundle 3 and the heat exchange pipe 4 when arranging the warm pipe unit, which can improve the firmness between the pipe bundle 3 and the heat exchange pipe 4, thereby further improving the service life of the heat exchange pipe 4.

[0031] The specific working process of the utility model is as follows: when the utility model is used, the condensate enters the cylinder 2, the steam in the steam pipe network enters the heating pipe 11 through the heat source inlet pipeline 10, and realizes mixing and temperature rise by entering the condensate through the uniformly distributed steam holes 13, the condensate is heated at a rate of not more than 30 DEG C per hour, so that the condensate temperature in the cylinder 2 rises to about 254 DEG C when the heat source enters the heat exchange pipe 4; at this time, the heat source (process gas) enters the heat exchange pipe 4 and exchanges heat with the condensate in the cylinder 2, the above process greatly shortens the temperature difference between the tube and the shell when the initial driving is started, effectively prevents the heat exchange pipe cracking problem caused by the temperature difference stress; further, by adopting the hydraulic expansion connection mode between the tube bundle 3 and the heat exchange pipe 4, the plastic deformation zone cracking caused by hole machining deviation and mechanical expansion at the tube plate can be effectively reduced, the possibility of chlorine ion aggregation and deposition is reduced, and the tube plate and heat exchange pipe material are changed to corrosion-resistant 15CrMOR, thereby effectively reducing the occurrence of heat exchange pipe stress corrosion cracking. Through the above setting, the operation time of the heat exchange pipe can be greatly improved, and the service life is effectively prolonged; thereby the advantages of reducing the maintenance engineering quantity and the maintenance cost are achieved.

[0032] The basic principle, main features and advantages of the utility model are shown and described above. It should be understood by the person skilled in the art that the utility model is not limited by the above examples, the above examples and the description in the specification are only to illustrate the principle of the utility model, various changes and improvements can be made to the utility model without departing from the spirit and scope of the utility model, and these changes and improvements all fall within the scope of the utility model claimed.

Claims

1. A medium pressure steam generator, characterized by: The medium-pressure steam generator comprises a tube box (1), a cylinder (2), a tube bundle (3) arranged between one side of the tube box (1) and the cylinder (2), a plurality of heat exchange tubes (4) arranged on the end face of the tube bundle (3), a waste heat source inlet (5) and a waste heat source outlet (6) arranged at the upper part and the lower part of the tube box (1) respectively, a partition plate (7) arranged at the middle part of the inner wall of the tube box (1) and the end face of the tube bundle (3), a steam outlet (8) arranged at the top of the cylinder (2), and a condensate inlet (9) arranged at the other side of the cylinder (2), wherein the lower part of the condensate inlet (9) is correspondingly provided with a warm tube unit for preheating and heating condensate in the cylinder (2).

2. A medium pressure steam generator according to claim 1, characterized in that: The warm tube unit comprises at least a heat source inlet pipeline (10) arranged at the lower part of the cylinder (2), and the heat source inlet pipeline (10) is in communication with a heating tube (11) arranged in the cylinder (2) and parallel to the heat exchange tube (4).

3. A medium pressure steam generator according to claim 2, characterised in that: The heating tube (11) is arranged at the middle lower part of the cylinder (2), and the heating tube (11) comprises three heating tubes, one of which is arranged at the middle position of the cylinder (2), and the other two are arranged at the two sides of the cylinder (2) respectively.

4. A medium pressure steam generator according to claim 2 or 3, characterised in that: The end of the heating tube (11) is provided with a pipe cap (12), and the surface of the heating tube (11) is uniformly provided with steam holes (13).

5. A medium pressure steam generator according to claim 2, characterized in that: The end of the heat source inlet pipeline (10) is provided with a flange (14) for connecting with a steam pipe network.

6. A medium pressure steam generator according to claim 2 or 5, characterised in that: A plurality of supporting rods (15) for fixing the heat source inlet pipeline (10) are arranged on the heat source inlet pipeline (10) in the cylinder (2), one end of the supporting rod (15) is connected with the outer wall of the heat source inlet pipeline (10), and the other end of the supporting rod (15) is connected with the inner wall of the cylinder (2).

7. A medium pressure steam generator according to claim 3, characterized in that: The lower part of the heating tube (11) on the two sides of the cylinder (2) is correspondingly provided with a side bracket platform (16) on the inner wall of the cylinder (2), the top of the side bracket platform (16) is fixedly connected with the outer circumference of the heating tube (11) through a U-shaped bolt (17), and the bottom of the side bracket platform (16) is provided with a reinforcing rib (18) connected with the inner wall of the cylinder (2).

8. A medium pressure steam generator according to claim 2, characterized in that: The overlapping ratio between the heating tube (11) and the heat exchange tube (4) is 1-2:

3.

9. A medium pressure steam generator according to claim 1, characterized in that: The tube bundle (3) and the heat exchange tube (4) are connected through hydraulic expansion.

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