JPH057637B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a heat exchange device, and more particularly, to a heat exchange device having a structure that facilitates corrosion countermeasures and easy maintenance and inspection when the heat exchange fluid is corrosive.

[Background of the invention]

Conventionally, heat exchange equipment has been used in cases where the heating fluid and the fluid to be heated are corrosive, such as when coke oven gas (hereinafter abbreviated as COG) in steel plants is cooled with seawater, as shown in Figures 1 and 2. The type shown is often used. FIG. 1 is a sectional view showing a schematic structure of a conventional heat exchange device, and FIG. 2 is a sectional view taken along line AA in FIG.

COG flows through a high-temperature gas duct 1 at about 900°C, and a large number of finned heat exchange tubes 2 are installed in this high-temperature gas duct 1, and each finned heat exchange tube is connected to a low-temperature fluid flow path 3. After being bundled and cooled with seawater to condense and remove the moisture in the COG, it is reused as fuel.

However, the problem in this case is that seawater is highly corrosive, so the welded connection between the low-temperature fluid flow path 3, which is the seawater flow path, and the finned heat exchange tube 2 is severely corroded, and the finned heat exchange tube 2 is severely corroded. The replacement tube 2 is a consumable item and needs to be replaced frequently.

In addition, if a hole develops in the finned heat exchange tube due to corrosion, seawater, which is the cooling fluid, may
It mixes into COG and causes a major problem of deterioration in the quality of COG used as fuel.

[Purpose of the invention]

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, provide corrosion countermeasures and easy maintenance and inspection, and eliminate the risk of mixing of heating fluid and heated fluid even if leakage occurs due to corrosion. To provide heat exchange equipment.

[Summary of the invention]

In short, in the present invention, a corrosive low-temperature fluid is passed through a group of heat transfer tubes provided with communication portions that allow the heat transfer medium to freely flow so that the heat transfer medium can repeatedly evaporate and condense to transfer heat. This heat exchange device has a compact structure, and includes an upper heat exchange section that allows the high-temperature fluid to pass through, and a lower heat exchange section that passes the high-temperature fluid adjacent to the low-temperature fluid, and transfers heat via the heat transfer medium.

More specifically, the upper heat exchange section is a group of horizontal multi-tube heat transfer tubes in which a corrosive low-temperature fluid passes through the tubes and a heat transfer medium is circulated outside the tubes, and the lower heat exchange section is configured as The above-mentioned heat transfer medium is used as a group of vertical multi-tube heat transfer tubes that allow high temperature fluid to pass outside the tubes adjacent to the fluid and circulate the heat transfer medium inside the tubes.
Corrosion countermeasures and maintenance and inspection of the structure in which heat is exchanged by flowing between the upper heat exchange section and the lower heat exchange section are easy, and even if leakage occurs due to corrosion, the heating fluid and the heated This is a heat exchange device with no risk of mixing with fluids.

[Embodiments of the invention]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing a schematic structure of a heat exchange device according to an embodiment of the present invention. FIG. 4 is a sectional view taken along the line AA in FIG. 3. As is clear from the figure, a plurality of finned heat exchange tubes 4 are arranged in the high temperature gas duct 1, and the lower end of each finned heat exchange tube 4 is communicated with each finned heat exchange tube 4 through a communication pipe 5. has been done. On the other hand, the upper end of the finned heat exchange tube 4 communicates with each finned heat exchange tube through a header 6. Inside the header 6, a plurality of heat exchange tubes 7 are arranged by tube plates 8 at both ends of the header 6. Here, a heat transfer medium such as water, Freon, Dowsum, etc. is vacuum sealed in the heat exchange tube 4 with fins.

While the high-temperature gas flows through the outer surface of the finned heat exchange tube 4 disposed in the high-temperature gas duct 1,
Heat is applied to the heat transfer medium sealed inside the tube to evaporate the heat transfer medium. The evaporated heat transfer medium flows into the header 6 installed at the top. On the other hand, the low-temperature fluid flows from the low-temperature fluid passage 3 into the heat exchange tube 7 disposed in the header 6, where it receives heat from the steam of the heat transfer medium in the header 6 and is heated. . The steam of the heat transfer medium in the header 6 condenses and liquefies on the outer surface of the heat exchange tube 7, flows down into the finned exchange tube 4 disposed at the bottom, and transfers heat from the high-temperature gas outside the tube again. The heat exchange process described above is repeated.

Incidentally, by connecting a plurality of heat exchangers having the structure shown in FIG. 3, it is possible to increase or decrease the amount of heat exchanged.

Here, if the low-temperature fluid is corrosive, it is only necessary to consider corrosion protection for the inner surface of the low-temperature fluid flow path 3, one side of the tube plate 8, and the inner surface of the heat exchange tube 7. The structure allows for easy selection of anti-corrosion coatings and replacement of component parts.

Furthermore, even if the heat exchange tube 7 etc. is corroded due to the corrosive nature of the low temperature fluid and a hole is formed and the low temperature fluid leaks, the low temperature fluid will flow into the header 6 and the finned heat exchange tube 4. Only with
There is no risk of hot gas flowing into the duct 1.

Furthermore, the low-temperature fluid flow path 3 is attached using a flange structure 9, making daily maintenance and inspection, and replacement and repair of the heat exchange tube easy.

Furthermore, although the heat exchanger tube 4 with fins is used in the heat exchanger shown in FIG. It goes without saying that bare tubes can be used instead of heat exchange tubes.

Note that when the heat source is radiant heat from a high-temperature solid or fluid, a longitudinal fin shape is preferable.

〔Effect of the invention〕

As explained in detail above, the heat exchanger according to the present invention has a compact structure, and corrosion countermeasures are easy.Even if the heat exchange fluid leaks due to corrosion, the heating fluid and the heated fluid can be directly mixed. There is no risk of damage, maintenance and inspection are easy, and the heat exchange tube can be easily replaced and repaired, which has great practical merits.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the schematic structure of a conventional heat exchange device, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is a schematic structure of a heat exchange device according to an embodiment of the present invention. The sectional view shown in FIG. 4 is a sectional view taken along the line BB in FIG. 3. 1... High temperature gas duct, 2... Heat exchange tube with fins, 3... Low temperature fluid flow path, 4... Heat exchange tube with fins, 5... Communication pipe, 6... Header,
7... Heat exchange tube, 8... Tube plate, 9... Flange structure, a... Upper heat exchange section, b... Lower heat exchange section.

Claims (1)

[Claims] 1 A group of heat transfer tubes is provided with a communication section that allows the heat transfer medium to freely flow so that the heat transfer medium can undergo repeated heat transfer through evaporation and condensation, and the group of heat transfer tubes has corrosive properties. An upper heat exchange section through which a low-temperature fluid passes, and a lower heat exchange section through which a high-temperature fluid passes adjacent to the low-temperature fluid are provided, and the heat transfer medium is passed between the upper heat exchange section and the lower heat exchange section. A heat exchange device that exchanges heat by making it flow, and the upper heat exchange part is a horizontal multi-tube heat exchanger tube that allows a corrosive low-temperature fluid to pass through the tube and allows a heat transfer medium to flow outside the tube. group, and the lower heat exchange section,
A heat exchange device characterized by a group of vertical multi-tube heat transfer tubes that allows a high temperature fluid to pass outside the tubes and a heat transfer medium to flow inside the tubes.