CN212030309U

CN212030309U - Heating furnace with variable-pitch finned tube

Info

Publication number: CN212030309U
Application number: CN202020208599.9U
Authority: CN
Inventors: 陈孙艺
Original assignee: Challenge Petrochemical Machinery Corp
Current assignee: Challenge Petrochemical Machinery Corp
Priority date: 2020-02-25
Filing date: 2020-02-25
Publication date: 2020-11-27
Anticipated expiration: 2030-02-25

Abstract

The utility model discloses a take heating furnace of variable pitch finned tube, including the brickwork that encloses into furnace, be equipped with tube sheet, support and finned tube in the furnace, the finned tube includes parent tube and the spiral winding fin outside the parent tube, along the length direction of parent tube, the pitch of fin is changeable, the fin pitch of the section winding of the higher middle part region of furnace chamber temperature is less, the fin is denser, the heat transfer can be higher; the pitch of the fins wound on four corners with lower temperature of the furnace chamber and pipe sections in the peripheral area is larger, the fins are more sparse, smoke dust and falling objects on the furnace wall can be conveniently removed, the fin tube not only has larger heat exchange area of the traditional fin tube, but also has strong baffling effect on airflow by a larger helical angle, and the larger pitch of the fins also enables the flue gas airflow to go deep into the roots of the fins, so that the boundary layer is thinned, the heat transfer coefficient of the membrane is improved, the flow path of the airflow in the heating furnace is also prolonged, and the fin tube is more suitable for the requirements of various high-efficiency energy-saving.

Description

Heating furnace with variable-pitch finned tube

Technical Field

The utility model relates to a petroleum refining, petrochemical, coal industry, electric power energy industry and other chemical industry process reinforce the novel bull winding finned tube heating furnace of heat transfer to fluid medium belongs to the design and the construction technical field in the mechanical engineering equipment, concretely relates to heating furnace of area variable pitch finned tube.

Background

The heating furnace using the finned tube as the heat exchange element comprises a shell and tube heating furnace, a sleeve heating furnace, a finned tube air cooler, a heat pipe heating furnace, an atmospheric pressure furnace, a decompression furnace, a hydrogen making furnace, a reforming furnace, a coking furnace, a reforming furnace, a cracking furnace and the like. The tubular furnace functions to heat the medium (crude oil, oil or gas) to the temperature required by the process for refining, decomposition or synthesis. The special equipment for finned tube heating furnace belongs to high-efficiency heat-exchange energy-saving equipment, and can be used for heat exchange requirements of petroleum refining and chemical industry, coal chemical industry, chemical fertilizer, air conditioner, air cooling, electric power facility equipment and the like, including application modes of heating or cooling medium and the like. The description only takes the heating furnace as an example to describe the multi-head composite finned tube heating furnace and the manufacturing process thereof, but the principle is also applicable to other heat exchange equipment.

The four sides of the furnace body are surrounded by high furnace walls to form a hearth, the furnace walls are formed by laying and welding steel plates on I-shaped steel frames and the like, heat-insulating nails are distributed and welded on the steel plates, and heat-insulating and wear-resisting materials are cast between the heat-insulating nails. A support arranged on a furnace wall supports a tube plate, a multi-head winding finned tube penetrates through the tube plate with holes and is supported by the tube plate, two ends of the multi-head winding finned tube are connected through elbows, oil to be heated flows through the multi-head winding finned tube, high-temperature smoke or hot air vertically flows from bottom to top (or horizontally from left to right or from right to left) outside the multi-head winding finned tube in a hearth, and heat is transferred to the oil in the tube through the tube wall. The multi-head winding finned tube is a key element of the heating furnace, the heat exchange performance of the multi-head winding finned tube fundamentally determines the heat exchange efficiency of the whole furnace, and the quality of the multi-head winding finned tube affects the safe operation of the heating furnace.

Generally, in order to sufficiently balance and utilize various heat sources, a heating furnace is formed by stacking seven sets of modules having the same structure as shown in fig. 1. In order to improve the heat exchange area, people invent finned tubes, namely, steel strips are spirally wound on the outer surface of a common steel tube to extend and enlarge the area of the outer surface of the tube to improve the heat exchange effect, so that the finned tubes have higher use value, but engineering actual measurement shows that when high-temperature flue gas provided by a plurality of dispersedly-arranged burners with limited quantity flows through a furnace chamber with a rectangular cross section, the flow state is uneven, the temperature of the cross section at the same height in the furnace chamber is uneven, generally, the middle temperature is high, and the temperature of four corners is low, so that for the finned tubes with regular and uniform specification and size, the temperature of some tube sections in the furnace chamber is high, the heat exchange capacity is insufficient, the temperature of some tube sections in the furnace chamber is low, and the heat exchange capacity is.

With the large-scale development of petrochemical equipment, the capacity of a heating furnace is also improved, a heating furnace body designed according to the traditional concept is huge, even one module in the heating furnace of 15 ten thousand tons per year is 150 tons, the length is 26000mm, the width is 4200mm, and the height is 4000mm, so that the corresponding difficulties are brought to the pre-manufacturing, long-distance transportation and high-altitude precise hoisting of a product workshop, and the total construction period and the cost are also higher.

In conclusion, the traditional winding finned tube has obvious defects, and a new technical idea must be searched for the large-scale development of the heating furnace using the finned tube as the heat exchange tube. Therefore, the petrochemical heating furnace is improved in design and construction technology, the heat efficiency and the economic benefit of the heating furnace can be improved, and the method has strong engineering and social and economic significance.

Disclosure of Invention

There is above-mentioned technical problem to prior art, the utility model provides a take heating furnace of variable pitch finned tube can enough improve heat exchange efficiency, is convenient for again to unload the junk on smoke and dust and the furnace wall.

In order to achieve the above object, the utility model provides a following technical scheme:

the heating furnace with the variable-pitch finned tubes comprises a furnace wall enclosing a hearth, wherein the furnace wall comprises a section steel frame and a steel plate, the steel plate is welded on the section steel frame, a plurality of heat-preservation nails are distributed and welded on the steel plate, and a heat-insulation wear-resistant layer is cast among the heat-preservation nails; a tube plate, a support and finned tubes are arranged in the hearth, the support is fixed on the furnace wall and used for supporting the tube plate, a plurality of supporting holes are formed in the tube plate, and the finned tubes penetrate through the supporting holes, so that the finned tubes are supported by the tube plate; the finned tube comprises a base tube and fins spirally wound outside the base tube, and the screw pitches of the fins are changed along the length direction of the base tube, so that the finned tube forms a fin dense section and a fin sparse section, the fin dense section is located in the middle of the hearth, and the fin sparse section is located in a region, close to a furnace wall, of the hearth.

Preferably, the pitch of the fins is gradual or abrupt along the length of the base pipe.

Preferably, the top of the fin is smooth, or the top of the fin is toothed or provided with a plurality of U-shaped notches.

Preferably, the central line of the base pipe is a straight line, a spiral line, a circular ring line or a bent tubular line.

Preferably, the fins are screwed and fixed on the base pipe, or the fins and the base pipe are welded and fixed with each other.

Preferably, the cross section of the fin is flat or corrugated.

Preferably, the height of the fins varies along the length of the base pipe.

Preferably, the base tube material and the fin material may be the same or different.

Preferably, adjacent finned tubes in the furnace are in various combinations, for example, adjacent variable pitch wound fins are of the same material and have the same outside dimensions, or adjacent variable pitch wound fins are of the same material and have different outside dimensions, or adjacent variable pitch wound fins are of different material and have the same outside dimensions, or adjacent variable pitch wound fins are of different material and have different outside dimensions.

The utility model has the advantages that:

the utility model discloses a take heating furnace of variable pitch finned tube, including enclosing into the furnace wall of furnace, the furnace wall includes shaped steel steelframe and steel sheet, and the steel sheet welds in shaped steel steelframe, and it welds a plurality of heat preservation nails to distribute on the steel sheet, and the casting has thermal-insulated wearing layer between a plurality of heat preservation nails; the furnace wall is provided with a furnace wall, a furnace wall is arranged in the furnace wall, the furnace wall is provided with a plurality of furnace walls, and the furnace wall is provided with a plurality of furnace walls; the finned tube comprises a base tube and fins spirally wound outside the base tube, the pitch of the fins is changed along the length direction of the base tube, the pitch of the fins wound on the tube section in the middle area with higher temperature of the furnace chamber is smaller, the fins are denser, and the heat exchange energy is higher; the pitch of the fins wound on the four corners and the peripheral area of the furnace chamber with lower temperature is larger, and the fins are more sparse, so that smoke dust and falling objects on the furnace wall can be conveniently removed. The heating furnace composed of the multiple functions has larger heat exchange area of the traditional finned tube, larger helical angle also has strong baffling effect on airflow, and larger pitch of the fin also enables the flue gas airflow to go deep into the root of the fin, thereby thinning the boundary layer, improving the film heat transfer coefficient, prolonging the flow path of the airflow in the heating furnace, and being more suitable for the requirements of various high-efficiency energy-saving devices.

Drawings

FIG. 1 is a schematic view of a prior art furnace.

Fig. 2 is a perspective view of one module of the heating furnace in the embodiment.

FIG. 3 is a schematic view of a section of variable pitch wound finned tube having an outside diameter of phi and a left winding pitch of T₁The height of the fins is h₁The helix angle between the fin and the base tube is beta₁The right winding pitch is T₂The height of the fins is h₂The helix angle between the fin and the base tube is beta₂。

Reference numerals:

the furnace comprises a furnace wall 1, a tube plate 2, a bracket 3 and a finned tube 4.

Detailed Description

The present invention will be described in detail with reference to the following embodiments and accompanying drawings.

The heating furnace of a take variable pitch finned tube of this embodiment, as shown in fig. 2 and 3, including enclosing into furnace wall 1 of furnace, furnace wall 1 includes shaped steel steelframe and steel sheet, and the steel sheet welds in the shaped steel steelframe, and it has a plurality of heat preservation nails to distribute on the steel sheet to weld, and the casting has thermal-insulated wearing layer between a plurality of heat preservation nails. The furnace is internally provided with a tube plate 2, a bracket 3 and a finned tube 4, the bracket 3 is fixed on the furnace wall 1 and is used for supporting the tube plate 2, the tube plate 2 is provided with a plurality of supporting holes, and the finned tube 4 passes through the supporting holes, so that the finned tube 4 is supported by the tube plate 2. The finned tube 4 comprises a base tube and fins spirally wound outside the base tube, and the screw pitches of the fins are changed along the length direction of the base tube, so that the finned tube forms a fin dense section and a fin sparse section, the fin dense section is located in the middle of a hearth, and the fin sparse section is located in the area, close to a furnace wall, of the hearth. The pitch of the fins wound on the pipe section in the middle area with higher temperature of the furnace chamber is smaller, the fins are denser, and the heat exchange energy is higher; the pitch of the fins wound on the four corners and the peripheral area of the furnace chamber with lower temperature is larger, and the fins are more sparse, so that smoke dust and falling objects on the furnace wall can be conveniently removed. The height of the fins is increased so as to keep the heat exchange area and the heat exchange capacity not to be reduced, the heating furnace formed by the multiple functions not only has larger heat exchange area of the traditional finned tube, larger helical angle also has strong baffling effect on airflow, and larger pitch of the fins also enables the flue gas airflow to go deep into the roots of the fins, thereby thinning a boundary layer, improving the film heat transfer coefficient, prolonging the flow path of the airflow in the heating furnace, and being more suitable for the requirements of various high-efficiency energy-saving devices.

In this embodiment, the pitch of the fins is gradual, increasing or decreasing along the length of the substrate tube. Or in practice, it may instead be abrupt, for example with one segment having the same pitch value and the other segment having another pitch value.

In practice, the top of the fin is smooth, or the top of the fin is toothed or provided with a plurality of U-shaped notches, so that the heat exchange area can be increased. The central line of the base tube is a straight line, a spiral line, a circular line or a bent tubular line, and the base tube and the corresponding fins in corresponding shapes can be selected according to the shape structure of the heat exchanger. The fins are screwed and clamped on the base pipe, or the fins and the base pipe are welded and fixed with each other. The cross section of the fin is flat or corrugated. The height of the fins varies along the length of the substrate tube, e.g. the fins of the same substrate tube vary in height from this end of the substrate tube to the other end, including from high to low and then from low to high.

The manufacturers of the equal-pitch spiral finned tubes are many, the manufacturers for manufacturing finned tube production equipment are few, and the conditions for producing the variable-pitch finned tubes can be met only by modifying a finned tube welding device on the traditional finned tube production equipment when the variable-pitch finned tubes are manufactured. The synchronous matching of the moving mechanism and the welding mechanism is realized by transforming the constant speed operation of a motor for dragging the base tube of the finned tube into dynamic speed regulation operation, dragging out the variable pitch through the variable speed and interlocking the variable speed and the welding parameters.

Inspection is an important means of ensuring new finned tubes. And manufacturing a special pitch detection template according to a standard or design drawing, and performing quality detection on the variable pitch finned tube on the structural appearance, the geometric dimension, the welding rate, the pressure resistance and the like.

And assembling the heating furnace. And (4) discharging pipes according to the pipe discharging mode required by the design drawing strictly. The other construction modes of the heating furnace are the same as the traditional process.

It should be finally noted that the above embodiments are only intended to illustrate the technical solutions of the present invention, and not to limit the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention can be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A heating furnace with variable-pitch finned tubes comprises a furnace wall enclosing a hearth, wherein the furnace wall comprises a section steel frame and a steel plate, the steel plate is welded on the section steel frame, a plurality of heat-preservation nails are distributed and welded on the steel plate, and heat-insulation wear-resistant layers are cast among the heat-preservation nails; a tube plate, a support and finned tubes are arranged in the hearth, the support is fixed on the furnace wall and used for supporting the tube plate, a plurality of supporting holes are formed in the tube plate, and the finned tubes penetrate through the supporting holes, so that the finned tubes are supported by the tube plate; the method is characterized in that: the finned tube comprises a base tube and fins spirally wound outside the base tube, and the screw pitches of the fins are changed along the length direction of the base tube, so that the finned tube forms a fin dense section and a fin sparse section, the fin dense section is located in the middle of the hearth, and the fin sparse section is located in a region, close to a furnace wall, of the hearth.

2. A heating furnace with variable pitch finned tubes in accordance with claim 1, wherein: the pitch of the fins is gradual or abrupt along the length of the base pipe.

3. A heating furnace with variable pitch finned tubes in accordance with claim 1, wherein: the top of the fin is smooth, or the top of the fin is toothed or provided with a plurality of U-shaped notches.

4. A heating furnace with variable pitch finned tubes in accordance with claim 1, wherein: the central line of the base pipe is a straight line, a spiral line, a circular line or a bent tubular line.

5. A heating furnace with variable pitch finned tubes in accordance with claim 1, wherein: the fins are fixed on the base pipe in a screwing mode, or the fins and the base pipe are fixed in a welding mode.

6. A heating furnace with variable pitch finned tubes in accordance with claim 1, wherein: the cross section of the fin is flat or corrugated.

7. A heating furnace with variable pitch finned tubes in accordance with claim 1, wherein: the height of the fins varies along the length of the base pipe.