JPS6232386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direct-fired high-temperature regenerator, and more particularly to a direct-fired high-temperature regenerator (hereinafter sometimes simply referred to as a regenerator) used in an absorption refrigerator cycle.

The regenerator is a device that heats and concentrates a dilute lithium bromide (hereinafter referred to as LiBr) solution that has absorbed refrigerant vapor generated in the evaporator in an absorption refrigerator cycle to obtain a concentrated LiBr solution and refrigerant vapor. In the regenerator of an absorption refrigerator cycle that uses LiBr solution as the absorption liquid, the liquid temperature is 160°C or higher, and the LiBr concentration of the liquid is 60°C or higher.
It is concentrated to 65%, but as shown in Figure 1, LiBr
It has been confirmed that when the LiBr concentration of the solution is at the above concentration level (examples with LiBr concentrations of 62% and 65% are shown in the figure), the corrosion rate of metal increases rapidly when the temperature rises to 175°C or higher. ing.

Therefore, when designing and manufacturing a regenerator, it is necessary to improve the heat exchange performance, uniform the amount of heat exchange inside the regenerator, and maintain the liquid temperature uniformly at a low temperature (below 175℃). In order to prevent local concentration due to the occurrence of stagnation areas, it is necessary to flow the liquid uniformly.

A conventional direct-fired high-temperature regenerator consisting of a furnace cylinder section and a solution tube group section will be explained with reference to FIGS. 2, 3, and 4. The regenerator 1 includes a burner 10, a furnace tube 11, a solution tube 12 following the furnace tube 11, an outer tube 13, and a chimney 14. Furnace tube 1 determined by the dimensions of flame 21
1 has a flat upper part and a round lower part as shown in FIG. This is because boiling occurs from all around the furnace cylinder, but due to the bubbles 31 generated at the bottom.
This is to uniformize the liquid temperature by smoothly moving the LiBr solution 30 to the top, and to prevent local concentration. On the other hand, multiple solution tubes 1
As shown in FIG. 4, the solution tube group section constituted by 2 has a flat top and bottom, so that boiling mainly occurs within the solution tube 12, so there are relatively few problems in liquid flow.

Although a regenerator with such a structure is desirable from the viewpoint of preventing corrosion caused by LiBr,
1 and the outer cylinder 13 are round, there is a limit in terms of manufacturing cost reduction and VA, and there is also a drawback that the occupied area becomes large when it is incorporated into a refrigerator cycle. Furthermore, since it is difficult to reduce the amount of LiBr solution 30 present in the vessel, there is a drawback that the start-up time at startup and the operation time for diluting the LiBr solution at shutdown are relatively long.

Attempts have been made to develop a rectangular regenerator in order to overcome the above-mentioned drawbacks of the round regenerator. FIG. 5 shows the structure of a solution tube group of a conventional rectangular regenerator. According to this figure, the internal solution tube 12b and the end solution tube 12a are protruded and connected to the upper tube plate 15, and the lower tube It is retractably connected to the plate 16. As a result of studying the liquid flow in such a case using a bubble model, we found that, unlike the solution tube group section of the round regenerator shown in Figure 4, in the square type, the liquid 30 flowing down both ends of the solution tube group section is at the bottom. It has become clear that due to the abrupt change in the flow path, the main stream is disturbed as shown in the figure, and the supply of liquid to the end solution tube 12a is obstructed. Moreover, the combustion gas flowing outside the tube is connected to the inner tube 17 and the end solution tube 12a.
The amount of heat exchanged in the cross-sectional direction is also larger in the end solution tube 12a than in the internal solution tube 12b, and the amount of bubbles generated in the end solution tube 12a increases accordingly. It was found that the liquid also spouted out from the upper part of the solution tube 12a. As a result of this, the supply of liquid is obstructed in the lower part and the splashing of liquid is activated in the upper part, the liquid flow in the end solution pipe 12a fluctuates significantly temporally and locally. Temperature and concentration increase will occur, inducing local corrosion.

An object of the present invention is to provide a new direct-fired rectangular regenerator that eliminates the local corrosion caused by poor liquid flow that occurs in the solution tube group of the conventional direct-fired rectangular regenerator described above.

The gist of the present invention is to provide a direct-fired high-temperature regenerator consisting of a furnace cylinder section and a solution tube group section, in which the inner tube and the outer tube of the solution tube group section are made square, and the solution tube consists of an inner solution tube and an end solution tube. This direct-fired high-temperature regenerator is characterized in that liquid flow resistance increasing means is provided at the lower part of the former internal solution tube of the tube group.

Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 6 shows an example of the solution tube group of the regenerator of the present invention, and the solution tube group includes the internal solution tube 12.
b, end solution tube 12a, outer cylinder 13, upper tube plate 1
5. It is mainly composed of a lower tube plate 16 and an inner cylinder 17. In this figure, internal solution tube 12b
is protrudingly connected to the lower tube plate 16, thereby inhibiting the liquid from flowing into the internal solution tube 12b,
On the contrary, the inflow of liquid into the end solution tube 12a is promoted, and a balanced liquid flow state can be achieved as a whole in the solution tube group, so local corrosion in the end solution tube 12a is prevented. .

FIG. 7 shows another embodiment of the regenerator of the present invention, in which the internal solution tube 12b is protruded and connected to the lower tube plate 16 as in FIG. 6. Furthermore,
Since the regenerator main body has an inclined structure and the flat rectifying plate 18 is installed in the gas-liquid boundary area in the outer cylinder 13, the liquid flow in the solution tube group is further improved.

As described above, according to the rectangular regenerator of the present invention, temporal and local fluctuations in liquid flow in the end solution tube, which are inherent disadvantages of the rectangular regenerator, can be prevented, and local corrosion can be significantly reduced. I can do it.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between the concentration and temperature of LiBr solution and the corrosion rate of metal, Figure 2 is a vertical cross-sectional view of a conventional round regenerator, and Figure 3 is a cross-section along the - line in Figure 2. 4 is a sectional view taken along the line - in FIG. 2, FIG. 5 is a sectional view of the solution tube group of a conventional prismatic regenerator, and FIGS. 6 and 7 are sectional views of the prismatic regenerator of the present invention. FIG. 3 is a sectional view of the solution tube group portion of the container. 1... Regenerator main body, 10... Burner, 11... Furnace cylinder,
12... Solution tube, 12a... End solution tube, 12b... Internal solution tube, 13... Outer tube, 14... Chimney, 15... Upper tube plate, 16... Lower tube plate, 17... Inner tube, 18... Straightening plate.

Claims (1)

[Scope of Claims] 1. A square inner tube in which an inner solution tube and an end solution tube are erected and fixed between a furnace cylinder section, an upper tube sheet and a lower tube sheet, and a square outer tube that houses the inner tube. 1. A direct-fired high-temperature regenerator comprising a solution tube group formed by a cylinder and a solution tube group, the direct-fired high-temperature regenerator having a structure in which a lower end of the internal solution tube protrudes from the lower tube plate and is coupled to the lower end. 2. The direct-fired high-temperature regenerator according to claim 1, wherein the regenerator main body has an inclined structure, and a rectifying plate is provided in a gas-liquid boundary region at the center of the outer cylinder.