CN103512412B - U-shaped heat pipe heat exchanging component and the U-shaped heat exchange of heat pipe integrated with electrostatic precipitator - Google Patents

Abstract

The U-shaped heat pipe heat exchange element and the U-shaped heat pipe heat exchanger integrated with the electrostatic precipitator, the U-shaped heat pipe heat exchange element is composed of an integrally bent 180° elbow and two continuously extending straight sections, The U-shaped heat pipe heat exchanger includes a cooling fluid inlet header, a thermal fluid outlet header, and a plurality of cooling fluid casings connecting the cooling fluid inlet header and the thermal fluid outlet header, and also includes the A plurality of U-shaped heat pipe heat exchange elements are used as heat pipes. The upper part of the heat pipe is inserted into the cooling medium inlet header and inserted into the cooling medium sleeve. The top ends of the two straight sections of the heat pipe are sealed and welded and inserted into the heat working medium outlet header; The part of the heat pipe not inserted into the cooling medium inlet header is the evaporation heat absorption section, and the part inserted into the cooling medium inlet header is the condensation heat release section; the evaporation heat absorption section is installed inside the middle section of the inlet expansion section of the electrostatic precipitator, The condensing and exothermic section is placed outside the upper part of the flue in the middle section of the inlet expansion section of the electrostatic precipitator; the invention is suitable for the heat exchanger structure of large-scale equipment such as thermal power plants and petrochemical industries.

Description

U-shaped heat pipe heat exchange element and U-shaped heat pipe heat exchanger integrated with electrostatic precipitator

technical field

The invention relates to the technical field of heat pipe heat exchangers, in particular to a U-shaped heat pipe heat exchange element and a U-shaped heat pipe heat exchanger integrated with an electrostatic precipitator.

Background technique

When flue gas from boilers and industrial processes flows through the heating surface, its heat distribution is limited to a certain extent, resulting in high flue gas temperatures at the outlet of the air preheater and the inlet of the dust collector. In order to make full use of the heat in the flue gas, It can be realized by setting a waste heat recovery device in the flue gas channel before the bell mouth of the inlet section of the dust collector. However, in some cases, due to the limited space, the arrangement of the flue is extremely compact, and there is no straight section of the flue between the air preheater and the bell mouth of the dust collector inlet section to arrange the waste heat recovery device; sometimes although the straight section of the flue is designed, However, due to the arrangement of the denitrification reactor above the straight section of the flue, the waste heat recovery device is greatly limited. In view of this, this patent proposes to arrange the waste heat recovery device in the middle of the bell mouth of the dust collector inlet section, and reduce the temperature of the flue gas by absorbing the heat of the flue gas, which can effectively reduce the specific resistance of the dust; at the same time, because the temperature of the flue gas decreases, the flue gas The volume flow rate of the electrostatic precipitator is also reduced, and the flow rate of the flue gas entering the electrostatic precipitator is also reduced. These two effects can significantly improve the dust removal efficiency of the electrostatic precipitator.

If the waste heat recovery device is arranged in the middle of the bell mouth of the flue gas inlet section of the electrostatic precipitator, the water tube heat exchanger is generally used traditionally, and the tube bundle of the water tube heat exchanger can also be designed as H-shaped, spiral, pin-shaped fins, or plate-shaped Extended heating surfaces such as fins or coupling fins have a compact structure and low steel consumption, but the tube bundle of the water tube heat exchanger is filled with liquid working medium. Once the water tube heat exchanger bursts and leaks due to wear and corrosion of the tube bundle, The leakage of liquid working medium in the whole system may cause the blockage of the fly ash discharge valve of the dust collector, resulting in the unplanned forced shutdown of the equipment; and even if the heat pipe heat exchanger bursts and leaks, the quality of the working liquid filled in the heat pipe is very small , and is heated by the flue gas to evaporate rapidly, which will not cause the phenomenon of clogging of the fly ash discharge valve of the electrostatic precipitator, and avoid the unplanned forced shutdown caused by it.

The heat pipe is a high-efficiency heat transfer element. Its heat transfer process utilizes the two most intense processes of evaporation heat absorption and condensation heat release of phase change latent heat in heat transfer. It has extremely high thermal conductivity and good isothermal properties. , The heat transfer area on both sides of the cold and hot sides can be changed arbitrarily, long-distance heat transfer, temperature controllable and a series of advantages. The working principle of the heat pipe: the heat pipe absorbs the heat of the flue gas at the heat-absorbing end of the evaporation, and transfers the heat to the working medium in the tube. After absorbing heat, the working medium boils or evaporates and turns into steam. At the hot end, the steam condenses into a liquid state at the exothermic end of the heat pipe to release heat, heating the cold fluid outside the exothermic end, and the condensed liquid after the heat release of the steam in the tube flows back to the endothermic end of the evaporation by gravity, because the interior has been evacuated Or set it to a certain pressure, so the working medium is easy to evaporate and boil, and the start of the heat pipe is very fast.

However, in long-term use, the heat pipe is generally a straight pipe structure, and the working liquid is filled in the straight pipe, which requires sealing and welding at both ends; the heat pipe with the straight pipe structure has a fixed heat transfer limit of the working fluid in the pipe, and cannot adapt to the temperature change condition; The structure of the heat pipe is in the state of a cantilever beam in the heat exchanger, and its rigidity is small. It is only suitable for small heat exchangers and is not suitable for the heat exchanger structure of large-scale equipment such as thermal power plants and petrochemical industries; at the same time, the heat pipe with a single straight pipe structure , both ends of the heat exchanger need to be sealed and welded. When the heat exchanger tube bundle is dense, the welding workload will increase exponentially, and the production cycle will be long, which limits the design and manufacture of large heat pipe heat exchangers. For a long time, straight heat pipes can only be used for small The size of the heat exchanger and the enlargement of the heat pipe heat exchanger are greatly limited.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the object of the present invention is to provide a U-shaped heat pipe heat exchange element and a U-shaped heat pipe heat exchanger integrated with an electrostatic precipitator, which are suitable for large-scale equipment such as thermal power plants and petrochemical industries. heater structure.

To achieve the above object, the present invention adopts the following technical solutions:

A U-shaped heat pipe heat exchange element is composed of an integrally bent 180° elbow and two continuously extending straight sections. Its extended heating surface adopts H-shaped, spiral, needle-shaped fins, plate-shaped fins or coupling fins.

The U-shaped heat pipe heat exchanger integrated with the electrostatic precipitator, including the cooling working medium inlet header 4, the thermal working medium outlet header 1, and a plurality of connecting cooling working medium inlet header 4 and the thermal working medium outlet header 1 The cooling medium sleeve 3 also includes the above-mentioned multiple U-shaped heat pipe heat exchange elements as heat pipes 2, the upper part of the heat pipe 2 is inserted into the cooling medium inlet header 4, and inserted into the cooling medium sleeve 3 The tops of the two straight sections 2-2 of the heat pipe 2 are sealed and welded and inserted into the thermal fluid outlet header 1; the part of the heat pipe 2 that is not inserted into the cooling fluid inlet header 4 is an evaporative heat-absorbing section, which is inserted into the cooling medium The part inside the inlet header 4 is the condensation heat release section; the evaporation heat absorption section is installed inside the flue in the middle section of the inlet extension section of the electrostatic precipitator, and the condensation heat release section is placed in the middle section of the inlet extension section of the electrostatic precipitator The outer upper part of the flue.

The heat pipe 2 is fixed inside the flue in the middle section of the inlet expansion section of the electrostatic precipitator through the middle partition plate 5 .

The plane of the 180° elbow of the heat pipe 2 is arranged perpendicular to or parallel to the flow direction of the flue gas.

The outer side of the evaporating heat-absorbing section of the heat pipe 2 adopts H-shaped, spiral, needle-shaped fins, plate-shaped fins or coupling fins to expand the heating surface.

Compared with the prior art, the present invention has the following advantages:

1. The present invention uses U-shaped heat pipes for heat exchange. U-shaped heat pipes are structurally equivalent to two straight heat pipes, but the rigidity of the system is increased. It is suitable for the heat exchanger structure of large-scale equipment such as thermal power plants and petrochemical industries. The heat exchanger is in the state of a cantilever beam with low rigidity and is only suitable for small heat exchangers.

2. The present invention uses U-shaped heat pipes for heat exchange. Compared with the use of a single straight heat pipe, each U-shaped heat pipe is structurally equivalent to two straight heat pipes, and only two pipe ends need to be sealed and welded. Two straight heat pipes need 4 pipe ends are sealed and welded, so the workload of sealing and welding the pipe ends is reduced by half.

3. In the present invention, the U-shaped heat pipe is placed in the flue, and the evaporation heat transfer limit in the two straight sections of the U-shaped heat pipe can be adjusted according to the uneven temperature distribution of the flow section, making it a U-shaped heat pipe with a variable heat transfer limit. A single straight heat pipe has obvious heat transfer safety.

4. The U-shaped heat pipe heat exchanger of the present invention is arranged in the middle section of the inlet expansion section of the electrostatic precipitator. Once the wall thickness is thinned due to wear or corrosion and the pipe bursts, the leakage of a single U-shaped pipe will not affect the overall heat exchanger. At the same time, even if a leak occurs, because the quality of the working liquid filled in the U-shaped tube is very small, and it is heated by the flue gas and evaporates rapidly, it will not cause a large amount of water leakage after a water pipe heat exchanger leaks. The phenomenon of clogging the fly ash discharge valve of the dust collector is caused, and the unplanned forced shutdown of the equipment caused by it is avoided.

5. The heat exchanger of the present invention is arranged in the middle section of the inlet expansion section of the dust collector, which can make full use of the flue space at the inlet of the electrostatic precipitator without adding additional floor space.

6. The U-shaped heat pipe heat exchanger of the present invention replaces the function of the equalizing plate in the bell mouth of the inlet section of the electrostatic precipitator, and plays the role of equalizing current, expanding heat exchange, and rapidly cooling and cooling, and can effectively reduce the exhaust gas temperature while completing the process. Waste heat recovery has the dual functions of cooling, saving energy and increasing efficiency through dust removal, and can realize long-term safe and efficient operation.

7. The present invention adopts modular design, compact structure, and is convenient for installation and disassembly.

Description of drawings

Figure 1 is a single U-shaped heat pipe heat exchange element.

Fig. 2 is a schematic diagram of the appearance of the present invention when it is installed and arranged.

Fig. 3 is a structural schematic diagram of the heat exchanger in the present invention.

Fig. 4 is a structural schematic diagram of the integrated installation of the heat exchanger and the electrostatic precipitator of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in FIG. 1 , a U-shaped heat pipe heat exchange element of the present invention is composed of an integrally bent 180° elbow 2-1 and two continuously extending straight sections 2-2. Its extended heating surface adopts H-shaped, spiral, needle-shaped fins, plate-shaped fins or coupling fins.

As shown in Figure 2 and Figure 3, the U-shaped heat pipe heat exchanger integrated with the electrostatic precipitator of the present invention includes a cooling working medium inlet header 4, a thermal working medium outlet header 1 and a cooling working medium inlet header 4 connected and a plurality of cooling medium casing pipes 3 of the thermal medium outlet header 1, and also include the above-mentioned multiple U-shaped heat pipe heat exchange elements as heat pipes 2, and the upper part of the heat pipe 2 is inserted into the cooling medium inlet header 4, and inserted into the cooling fluid casing 3, the top ends of the two straight sections 2-2 of the heat pipe 2 are sealed and welded and inserted into the thermal fluid outlet header 1; the heat pipe 2 is not inserted into the cooling fluid inlet header 4 The part of the evaporation heat absorption section is the evaporation heat absorption section, and the part inserted into the cooling working medium inlet header 4 is the condensation heat release section; the evaporation heat absorption section is installed inside the flue of the middle section of the inlet expansion section of the electrostatic precipitator, and the condensation heat release section The section is placed outside the upper part of the flue in the middle section of the inlet expansion section of the electrostatic precipitator.

As a preferred embodiment of the present invention, the heat pipe 2 is fixed inside the middle section of the inlet expansion section of the electrostatic precipitator through the middle partition 5 to realize the gas sealing.

As a preferred embodiment of the present invention, the plane of the 180° elbow of the heat pipe 2 is arranged perpendicular to or parallel to the flow direction of the flue gas.

As a preferred embodiment of the present invention, the outer side of the evaporative and heat-absorbing section of the heat pipe 2 adopts H-shaped, spiral, pin-shaped fins, plate-shaped fins or coupling fin-shaped extended heating surfaces.

As shown in Figure 4, it is a structural schematic diagram of the integrated installation of the heat exchanger and the electrostatic precipitator of the present invention, which can make full use of the flue space at the inlet of the electrostatic precipitator without adding additional floor space.

The working principle of the present invention is: the evaporative and heat-absorbing section of the heat pipe 2 is installed inside the flue of the middle section of the inlet extension section of the electrostatic precipitator to absorb the heat of the flue gas, and the heat is transferred to the internal working medium of the heat pipe through the U-shaped heat pipe wall, and the working medium After absorbing heat, the temperature rises and evaporates into steam. The steam rises to the condensing and exothermic section under the force generated by the pressure difference. The steam in the U-shaped heat pipe condenses and releases the latent heat of vaporization outward. The cooling medium sleeve 3 outside the heat pipe 2 The cooling medium is filled with cooling fluid, and convective heat exchange is performed on the upper part of the heat pipe 2, and the cooling fluid in the cooling fluid casing 3 is heated and cooled. After the steam condenses, it returns to the evaporation heat-absorbing section by gravity, and so on. The heat is continuously transferred to the cooling working medium, so that the cooling working medium is heated and the waste heat of the flue gas is effectively utilized.

Claims (5)

1. The U-shaped heat pipe heat exchanger integrated with the electrostatic precipitator, including the cooling fluid inlet header (4), the thermal fluid outlet header (1), and the cooling fluid inlet header (4) connected to the thermal fluid The plurality of cooling medium casings (3) of the mass outlet header (1) is characterized in that it also includes a plurality of heat pipes (2), and the heat pipes (2) are U-shaped heat pipe heat exchange elements, which are bent by a whole Formed 180° elbow (2-1) and two continuously extending straight sections (2-2); the upper part of the heat pipe (2) is inserted into the cooling working medium inlet header (4), and inserted into the cooling working medium In the heat pipe (3), the top ends of the two straight sections (2-2) of the heat pipe (2) are sealed and welded and inserted into the heat medium outlet header (1); the heat pipe (2) is not inserted into the cooling medium inlet The part inside the header (4) is the evaporating heat-absorbing section, and the part inserted into the inlet header (4) of the cooling working medium is the condensation heat-releasing section; Inside the duct, the condensing heat release section is placed outside the upper part of the flue duct in the middle section of the inlet extension section of the electrostatic precipitator. 2. The U-shaped heat pipe heat exchanger integrated with the electrostatic precipitator according to claim 1, characterized in that: the extended heating surface of the heat pipe (2) adopts H-shaped, spiral, needle-shaped fins, plate shaped fins or coupled fins. 3. The U-shaped heat pipe heat exchanger integrated with the electrostatic precipitator according to claim 1, characterized in that: the heat pipe (2) is fixed in the middle section of the inlet expansion section of the electrostatic precipitator through a middle partition (5) Inside the flue. 4. The U-shaped heat pipe heat exchanger integrated with the electrostatic precipitator according to claim 1, characterized in that: the plane of the 180° elbow of the heat pipe (2) is arranged perpendicular to the flow direction of the flue gas or parallel to the The direction of flue gas flow. 5. The U-shaped heat pipe heat exchanger integrated with the electrostatic precipitator according to claim 1, characterized in that: the outer side of the evaporation heat absorption section of the heat pipe (2) adopts H-shaped, spiral, needle-shaped fins Sheet, plate fin or coupling fin extended heating surface.