CN210179670U

CN210179670U - Efficient heat transfer self-ash-removing needle-shaped finned tube and heat exchanger

Info

Publication number: CN210179670U
Application number: CN201920340405.8U
Authority: CN
Inventors: Yanmin Zhu; 朱言敏; Tianjun Tian; 田田畯
Original assignee: SHANDONG HENGTAO ENERGY-SAVING ENVIRONMENT PROTECTION Co Ltd
Current assignee: SHANDONG HENGTAO ENERGY-SAVING ENVIRONMENT PROTECTION Co Ltd
Priority date: 2019-03-18
Filing date: 2019-03-18
Publication date: 2020-03-24
Anticipated expiration: 2029-03-18

Abstract

The utility model discloses a high-efficient heat transfer is from deashing aciculiform finned tube and heat exchanger, it belongs to the heat transfer field, including a pipe body, the body has a plurality of aciculiform fin group, every group along the axial equipartition aciculiform fin group includes a plurality of aciculiform fins, and a plurality of aciculiform fin roots evenly set up at the body surface, and parallel arrangement again after one section distance is extended to one side to the aciculiform fin of half quantity, and parallel arrangement again after one section distance is extended to the opposite side to the aciculiform fin of second half quantity, the aciculiform fin of half quantity sets up with the aciculiform fin symmetry of second half quantity, and the aciculiform fin tip of two half quantities all is perpendicular.

Description

Efficient heat transfer self-ash-removing needle-shaped finned tube and heat exchanger

Technical Field

The utility model relates to a heat transfer field, concretely relates to high-efficient heat transfer is from clear grey aciculiform finned tube and heat exchanger.

Background

China's thermal power plant mainly uses coal as fuel. The flue gas generated after coal combustion contains a large amount of fly ash particles, when the flue gas flows through a heated surface at a certain speed, the ash particles collide with the heated surface to rub and strip off trace materials, so that the pipe wall of the heated surface becomes thinner gradually, which is a process that the fly ash particles wear the heated surface. The safe operation of the boiler is seriously threatened by the abrasion of the heating surface caused by the scouring of fly ash particles, the design service life is often not reached in the actual operation, even the phenomenon of tube explosion occurs, and the spiral finned tube and the H-shaped finned tube are widely applied to heat exchange equipment in various fields of the market in order to increase the heat exchange area and avoid the problem of ash accumulation and abrasion as heat exchange elements, particularly in the aspects of boiler economizers and low-temperature waste heat utilization.

However, the application of the H-type finned tube and the helical finned tube, whether the light pipe or the helical finned tube, has the following problems:

1. although the light pipe economizer is simple to manufacture and convenient to overhaul, the light pipe economizer is widely applied, but the light pipe heat exchanger has large arrangement space, high vapor-water resistance, low heat exchange efficiency and poor primary abrasion resistance;

2. the spiral finned tube heat exchange equipment is easy to accumulate dust, particularly, the phenomena of dust accumulation, blockage and the like are easily caused under the condition of burning inferior coal, the smoke resistance is high, and the heat exchange efficiency of the whole boiler is influenced after the heat exchange equipment is blocked by the dust accumulation;

the flue gas flow rate of the area, close to the base pipe, of the root of the small seam of the H-shaped finned pipe is low, a low-speed area exists at the position, close to the base pipe, of the windward side of the first row of finned pipes, flow lines on two sides of the low-speed area are symmetrically inclined downwards, the leeward side of the first row of finned pipes and the windward side and the leeward side of the second row of finned pipes also have low-speed areas, the low-speed area range is wider than that of the windward side of the first row of finned pipes, the fact that wider dust deposits are easily formed at the position in the actual operation process is found, especially wedge-shaped dust deposits of two peaks are easily formed on the front side of the second row of finned pipes, and the low-speed area of the H-shaped finned pipes is gradually enlarged along with the increase.

4. The heat transfer performance of the spiral finned tube and the heat transfer performance of the H-shaped finned tube are greatly different, wherein the heat contact resistance is taken as a main influence factor, the finned tube is welded between the fin and the main tube, and the heat contact resistance is generated no matter the melting and pressure welding of high-frequency resistance heating or the melting and diffusion welding of brazing filler metal, so that the heat transfer effect is influenced;

5. the welding rate of the finned tubes in the two forms is less than 100 percent, and the welding rate is not easy to check;

6. after welding the finned tube made of alloy steel materials, stress relief heat treatment is needed; because the two finned tubes are formed by welding, the root parts of the finned tubes are welded unevenly, and accumulation, slag bonding and blockage phenomena are easy to form during operation;

7. the tensile strength of the spiral finned tubes is slightly lower than the standard requirement, and the strength and the wear resistance have defects, such as severe scouring and abrasion of the finned tubes due to high flue gas flow velocity and large particle hardness on a heating surface in a fluidized bed boiler.

The utility model discloses combine many years's of design and experience in use of relevant field, assisted by too strong professional knowledge, the design has made a high-efficient heat transfer from deashing acircular tube and heat exchanger, overcomes above-mentioned defect.

SUMMERY OF THE UTILITY MODEL

To the problem that exists among the prior art, the utility model provides a pair of high-efficient heat transfer is from deashing aciculiform finned tube and heat exchanger can improve the heat exchange efficiency of flue gas, improves the outer flue gas flow characteristic of heat exchanger pipeline, and the reinforcing is stand wear and tear, corrosion resisting capability.

In order to realize the purpose, the utility model discloses a technical scheme as follows: the high-efficiency heat transfer self-dust-cleaning needle-shaped finned tube comprises a tube body, wherein a plurality of needle-shaped fin groups are uniformly distributed on the tube body along the axial direction, each needle-shaped fin group comprises a plurality of needle-shaped fins, the roots of the plurality of needle-shaped fins are uniformly arranged on the outer surface of the tube body, one half of the needle-shaped fins extend to one side for a certain distance and then are arranged in parallel, the other half of the needle-shaped fins extend to the opposite side for a certain distance and then are arranged in parallel, the one half of the needle-shaped fins are symmetrically arranged with the other half of the needle-shaped fins, and the end parts of the two half of the.

As a preferable technical solution, the number of the pin fins is set to at least 6.

As a preferable technical scheme, the end parts of the pin fins of the two halves are flush.

A high-efficiency heat transfer self-deashing heat exchanger comprises the high-efficiency heat transfer self-deashing needle-shaped finned tube.

The utility model discloses an useful part lies in:

(1) the utility model discloses no matter the flue gas is horizontal or vertically erodees the pipe, and all aciculiform extension faces all can receive the transverse turbulence of flue gas to erode, and the air current forms the steady state swirl and the backward flow district of symmetry at the cylinder back of needle class, and thermal boundary layer is constantly destroyed and reforms formation to make whole heat transfer boundary layer attenuate, reduced the thermal resistance, improve heat transfer coefficient greatly.

(2) The utility model discloses aciculiform finned tube heat transfer coefficient is 3 ~ 5 times of fluorescent tube, and the nuschell number Nu of aciculiform finned tube is about 4 times of fluorescent tube, and heat transfer coefficient is greater than the heat transfer coefficient of fluorescent tube, and heat transfer performance obviously strengthens.

(3) The pin-shaped finned tube is of a cantilever beam structure, and can generate slight vibration under the impact of airflow in a high smoke velocity and vortex backflow area, so that the ash is difficult to accumulate continuously, and the heat transfer unit structure of the pin-shaped finned tube heat exchanger has strong self-cleaning capability due to strong turbulent flow scouring of smoke, so that even a small amount of accumulated ash is easily blown off, effective heat transfer is ensured, and the running economy is improved.

(4) The utility model discloses under same heat transfer volume, its weight, overall dimension can have by a relatively large margin decline, can effectively solve the not enough problem in space under certain circumstances.

Drawings

FIG. 1 is an axial view of a high efficiency heat transfer self-cleaning pin fin tube;

FIG. 2 is a schematic structural view of a high-efficiency heat transfer self-cleaning pin-shaped finned tube;

FIG. 3 is a schematic diagram of an installed high efficiency heat transfer self-cleaning ash heat exchanger;

FIG. 4 is an enlarged partial schematic view of an installed high efficiency heat transfer self-cleaning ash heat exchanger.

In the figure: 1-tube body and 2-needle-shaped fin.

Detailed Description

In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1, the high-efficiency heat transfer self-cleaning gray pin fin tube comprises a tube body 1, wherein a plurality of pin fin groups are uniformly distributed on the tube body 1 along the axial direction, each pin fin group comprises a plurality of pin fins 2, the roots of the plurality of pin fins 2 are uniformly arranged on the outer surface of the tube body 1, one half of the pin fins 2 extend to one side for a certain distance and then are arranged in parallel, the other half of the pin fins 2 extend to the opposite side for a certain distance and then are arranged in parallel, one half of the pin fins 2 and the other half of the pin fins 2 are symmetrically arranged, and the end parts of the two half of the pin fins 2 are perpendicular to the symmetrical plane between the two half of the pin fins 2.

The number of the needle fins 2 of the utility model is at least 6, and the end parts of the needle fins 2 of the two preferable halves are all parallel and level.

The utility model adopts the above structure flue gas no matter transversely or vertically erode body 1, all 2 expansion faces of pin fin can all receive the transverse turbulence of flue gas and erode, and the air current forms the steady-state swirl and the backward flow district of symmetry at 1 backs of body of pin fin 2, and the thermal boundary layer is constantly destroyed and reforms formation to make whole heat transfer boundary layer attenuate, reduced the thermal resistance, improve heat transfer coefficient greatly.

Taking the economizer as an example, the heat exchange at the flue gas side plays a leading role in the heat transfer process. The heat transfer can be enhanced by increasing the heat transfer area according to the flue gas side heat exchange quantity formula. And the heat exchange coefficient of the needle-shaped finned tube is 3-5 times of that of the light tube by testing a single tube heat transfer experiment. The thermal experiment detection of the needle-shaped finned tube bundle shows that the Nu of the needle-shaped finned tube bundle is about 4 times that of the light tube, the heat exchange coefficient is greatly higher than that of the light tube, and the heat transfer performance is obviously enhanced. The research literature related to the welded spiral finned tube indicates that the heat exchange coefficient of the welded spiral finned tube does not exceed 3 times of that of the light pipe generally.

The cleaning of the deposited dust, the deposited slag and the dirt on the heat transfer surface is an important work for maintaining heat exchange equipment such as an economizer and the like. Because the ash layer on the flue gas side of the economizer has a low heat conduction coefficient, the generated thermal resistance is high even if the dirt layer is thin. Each millimetre layer of slag corresponds to a 400 millimetre thick steel wall. The existence of dirt thermal resistance not only weakens heat transfer, but also causes the temperature of the pipe wall to be obviously raised, thereby easily overheating the pipe wall to burn out, and causing accidents. The heat exchanger heat transfer unit structure formed by the needle-shaped finned tubes has strong self-cleaning capability, even if a small amount of accumulated dust is blown off, effective heat transfer is ensured, and the running economy is improved.

The heat transfer element formed by the needle-shaped finned tubes has higher heat transfer efficiency, and is particularly suitable for the modification of the tail heating surface of a waste heat boiler, an oil-fired boiler, a gas-fired boiler, a fluidized bed/pulverized coal boiler and a flue gas deep cooler. Under the same heat exchange quantity, the weight and the external dimension of the heat exchanger can be greatly reduced.

The heat exchanger formed by the needle-shaped finned tubes has high enhanced heat exchange coefficient, the compactness and the economical efficiency of the boiler are improved, more importantly, the needle-shaped finned tubes can be applied to different temperature occasions by adjusting the lengths of the needle-shaped fins 2, for example, the lengths of the needle-shaped fins 2 can be changed between 25 mm and 60mm, the needle-shaped finned tubes can be used for high-temperature heat exchange at 1200 ℃, and when the needle-shaped finned tubes are used as condensers, the exhaust gas temperature can be reduced to below 75 ℃. At present, the power station boiler generally has overhigh exhaust gas temperature, the energy loss is 5 to 8 percent, the exhaust gas loss accounts for 80 percent of the total heat loss of the boiler, and the heat efficiency of the boiler can be obviously improved by using the device so as to improve the economical efficiency of the system. Analysis results show that after the heat exchange equipment is introduced, the coal consumption of the unit is reduced by 2.69 g/(kW h), and the efficiency is improved by 0.81-1%.

It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that various changes, modifications and/or alterations to the present invention may be made by those skilled in the art after reading the technical disclosure of the present invention, and all such equivalents may fall within the scope of the present invention as defined by the appended claims.

Claims

1. The utility model provides a high-efficient heat transfer is from deashing aciculiform finned tube which characterized in that: the tube body is uniformly provided with a plurality of needle fin groups along the axial direction, each needle fin group comprises a plurality of needle fins, the roots of the plurality of needle fins are uniformly arranged on the outer surface of the tube body, one half of the needle fins extend to one side for a certain distance and then are arranged in parallel, the other half of the needle fins extend to the opposite side for a certain distance and then are arranged in parallel, the one half of the needle fins and the other half of the needle fins are symmetrically arranged, and the end parts of the two half of the needle fins are perpendicular to the symmetrical plane between the two half of the needle fins.

2. A high efficiency heat transfer self-cleaning gray pin fin tube as set forth in claim 1, wherein: the number of the pin fins is at least set to 6.

3. A high efficiency heat transfer self-cleaning gray pin fin tube as set forth in claim 1, wherein: the end parts of the two halves of the pin fins are flush.

4. The utility model provides a high-efficient heat transfer is from deashing heat exchanger which characterized in that: the high-efficiency heat transfer self-cleaning gray pin fin tube comprises the high-efficiency heat transfer self-cleaning gray pin fin tube as claimed in any one of claims 1 to 3.