JPS6248787B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an immersion tube type direct-fired high-temperature regenerator, and particularly to an immersion-tube type direct-fired high-temperature regenerator (hereinafter referred to as a regenerator) used in an absorption refrigeration cycle.

This type of regenerator heats and concentrates a dilute lithium bromide (hereinafter referred to as LiBr) solution that has absorbed refrigerant vapor generated in the evaporator of an absorption refrigeration cycle.
It is for obtaining a concentrated LiBr solution and refrigerant vapor, for example, as shown in FIGS. 1 and 2.
Mainly includes a main body 1, a burner 10 attached to one end of the main body, and a furnace cylinder 11 penetrating through the main body 1.
It consists of solution pipes 12 and 13 provided in the furnace tube, a high-temperature combustion gas guide buttful 14 attached to the side wall of the furnace tube 11, and a chimney 15 provided at the other end of the main body 1. . High-temperature combustion gas 20 obtained by burning gas, kerosene, etc. in the burner 10 travels straight horizontally within the furnace tube 11 and flows around the smooth solution tube 12 and the finned solution tube 13 for heat exchange. After that, it is discharged from the chimney 15. On the other hand, LiBr solution 21
is heated to boiling in the furnace tube 11 and solution tubes 12 and 13. In such a regenerator, the liquid temperature is generally heated to about 160° C., and the LiBr solution is concentrated to a LiBr concentration of 60 to 65%. Figure 3 is a graph showing the relationship between the concentration of LiBr solution and the corrosion rate of metal.
% LiBr solution is in a stationary state, and c indicates a case where a LiBr solution with a LiBr concentration of 65% is in a fluid state. From this figure, it is clear that the corrosion rate of LiBr solution with a LiBr concentration of 60 to 65% increases rapidly when the temperature reaches 165 to 175℃, especially when it is in a stopped state. Therefore, when the liquid temperature exceeds 160℃, , the LiBr concentration is
If the liquid flow in the regenerator becomes 60 to 65% stagnant, significant corrosion will occur in the stagnation area.

In the past, corrosion caused by this LiBr solution occurred particularly in groups of solution tubes, and many accidents occurred due to holes in the tubes. Therefore, in order to investigate the cause of corrosion of this solution tube, the present inventors observed the flow of combustion gas and LiBr solution using a two-dimensional water flow model and a two-dimensional gas bubble model, respectively. As a result, regarding the flow of combustion gas, as shown in Fig. 4, most of the combustion gas 20
The remaining gas 22 flows through the region 31 of the solution tube group and is gradually cooled, but the remaining gas 22 flows through the region 30 between the end tube 33 of the solution tube group, the buttful 14, and the furnace cylinder side wall 32.
It has been found that the gas 23 flows with almost no cooling, and is pushed toward the furnace cylinder side wall 32 by the gas 23 flowing out from the solution tube group, increasing the temperature of the furnace cylinder side wall 32. Therefore, the furnace cylinder side wall 32 and the main body 1
The LiBr solution in the side wall flow path 24 between the two is heated by the furnace cylinder side wall 32 and generates water vapor.

The generation of water vapor in this side flow path 24
In order to investigate the effect on the flow of LiBr solution,
As a result of conducting a secondary bubble model experiment, it was found that LiBr solution flow failure as shown in FIG. 5 occurred. That is, the LiBr solution 21 heated and concentrated in the solution tubes 12 and 13 is oriented by the rectifying plate 25 and reaches the side flow channels 24 on both sides, and attempts to flow down the flow channels. Since the water vapor 26 generated in the channel obstructs this flow of the LiBr solution, the supply of the LiBr solution to the lower part of the solution pipe becomes insufficient. Therefore, a stagnation area 27 of the LiBr solution is generated in the lower part of the solution tube, and the flow condition in this stagnation area deteriorates and at the same time the temperature rises, resulting in severe corrosion in the lower part of the solution tube.

Corrosion due to poor flow of the LiBr solution occurs particularly in the boundary area between the smooth solution tube 12 and the finned solution tube 13. This is because when the combustion gas 20 flows into the finned solution tube group 13, the flow resistance suddenly increases, so a large amount of gas 23 flows from the solution tube group 13.
flows out toward the furnace cylinder side wall 12 and presses the high-temperature gas 22 flowing through the region 30 against the furnace cylinder side wall 32, so that the furnace cylinder side wall 32 is strongly heated, and at the same time, the LiBr solution is in this boundary area. Even if there is a shortage, LiBr will be received from the surrounding area.
This is because no solution is supplied.

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

The gist of the present invention is that a furnace cylinder and a group of solution tubes are arranged inside the main body, a high-temperature combustion gas guide baffle is attached to the side wall of the furnace cylinder, and a small common part of the side wall of the furnace cylinder is made to have an insulating structure. This is an immersion tube type direct-fired high-temperature regenerator.

Another aspect of the present invention is that a furnace cylinder and a group of solution tubes are arranged inside the main body, a high-temperature combustion gas guide baffle is attached to the side wall of the furnace cylinder, and a baffle for guiding high-temperature combustion gas is installed in the side flow path between the main body and the side wall of the furnace cylinder. , an immersion tube type direct-fired high-temperature regenerator characterized by being provided with a guide plate that divides the flow path.

Embodiments of the present invention will be described below with reference to FIGS. 6 to 9.

In the first embodiment shown in FIG. 6, a furnace cylinder side wall 32 is placed between the buffles 14 in the boundary area between the smooth solution tube 12 and the finned solution tube 13, which are strongly heated by the combustion gas 22. Partition plate 3 almost parallel to
5 is provided. The heat insulating chamber 36 formed by the partition plate 35 and the furnace cylinder side wall 32 is constructed by taking into consideration the thermal expansion of the partition plate 35 and the gas expansion in the heat insulating chamber 36, and as shown in FIG. By providing a flow passage space 37 between the two, it communicates with the gas chamber inside the furnace cylinder. Between this flow path chamber 37
has a width that does not adversely affect the flow of combustion gas 22.

In the case of a regenerator having such a structure, the high-temperature combustion gas 22 flows along the partition plate 35 without contacting the furnace cylinder side wall 32. A heat insulating chamber 36 is formed between the furnace cylinder side wall 32 and the partition plate 35 due to the stagnant gas. Therefore, the conduction of heat by the high-temperature combustion gas 22 to the furnace cylinder side wall 32 is reduced, and the temperature of the furnace cylinder side wall 32 does not rise much. Therefore, water vapor flows through the side flow path 2 between the furnace cylinder side wall 32 and the main body 1.
4, the LiBr solution circulates smoothly, and corrosion of the solution tubes 12 and 13 due to LiBr solution stagnation is significantly reduced.

In the second embodiment shown in FIG. 7, a heat insulating material 39 is attached to the side wall 32 of the furnace cylinder between the buttholes 14. This heat insulating material is, for example, firebrick, but it is necessary to select the material or the mounting method in consideration of thermal expansion.

In the above embodiment, the heat insulating layer is provided only in the boundary area between the smooth solution tube 12 and the finned solution tube 13, but the heat insulating layer can also be formed in other locations on the side wall 32 of the furnace cylinder. Further, the heat insulating material 39 can also be attached to the furnace cylinder side wall 32 on the side flow path 24 side.

The third embodiment of the inclined structure regenerator whose cross section is shown in FIG. 8 is different from the conventional regenerator shown in FIGS. It is different from the regenerator. This guide plate 34 divides the side passage 24 into two passages: one on the furnace cylinder side wall 32 side and the other on the main body 1 side.

Due to this guide plate arrangement structure, the LiBr solution flows as follows. Outflowed from solution tubes 12 and 13
The LiBr solution 21 is divided into left and right by a rectifying plate 25. LiBr solution 2 reaching the left side channel 24
1 flows down between the main body 1 and the guide plate 34 and flows back into the solution tubes 12 and 13 from below. The LiBr solution that has reached the right side flow path 24 flows down along the main body 1 due to the action of gravity, and similarly flows into the solution tubes 12 and 13.
flow inside. On the other hand, the water vapor 26 generated by the high-temperature furnace cylinder side wall 32 flows between the guide plate 34 and the furnace cylinder side wall 32 in the left side flow path 24.
4 due to buoyancy, it does not impede the flow of the LiBr solution. Since the water vapor 26 generated in the right side flow path 24 rises along the furnace cylinder side wall 32, it does not similarly impede the flow of the LiBr solution. Although the water vapor 26 crosses the flow of the LiBr solution 21 above the side channel 24, since this crossing point is an open system, the flow of the LiBr solution is not obstructed.

Therefore, the water vapor 26 generated within the side flow path 24
The LiBr solution 21 descending in the side wall channel flows smoothly into each other, and the LiBr solution circulates well without stagnation.

FIG. 9 shows a cross-section of a vertical regenerator according to a fourth embodiment of the invention. In this regenerator, vertically rising water vapor 26
In order not to obstruct the flow of the LiBr solution 21, guide plates 34 are provided in the left and right side channels 24, so that the flow of the LiBr solution 21 is improved, similar to the regenerator shown in FIG. Ru.

It is particularly advantageous to provide the guide plate 34 in the boundary region between the smooth tube 12 and the finned tube 13, where a large amount of water vapor 24 is generated.

As explained above, according to the present invention, poor flow of LiBr solution due to water vapor can be prevented, and local corrosion can be significantly reduced.

[Brief explanation of the drawing]

Figures 1 and 2 show a longitudinal cross-sectional view of a conventional direct-fired high-temperature regenerator and a cross-sectional view taken along the line, and Figure 3 shows the relationship between the concentration, temperature, and flow state of the LiBr solution and the corrosion rate of metal. Figures 4 and 5 are diagrams showing the flow state of combustion gas and LiBr solution in a conventional regenerator;
7, 8, and 9 are diagrams showing regenerators according to embodiments of the present invention. 1... Main body, 11... Furnace tube, 12... Smooth solution tube, 1
3... Solution tube with fins, 14... Bat full, 32... Furnace tube side wall, 34... Guide plate, 35... Partition plate, 36... Heat insulation chamber, 38... Gas chamber, 39... Heat insulation material.

Claims (1)

[Claims] 1. A furnace cylinder and a group of solution tubes are arranged inside the main body, a high-temperature combustion gas guiding baffle is attached to the side wall of the furnace cylinder, and a small common part of the side wall of the furnace cylinder has a heat-insulating structure. An immersion tube type direct firing high temperature regenerator. 2. Claim 1, in which a partition plate is provided approximately parallel to the side wall of the furnace cylinder between the bulges, and a heat insulating chamber formed by the partition plate and the side wall of the furnace cylinder is communicated with a gas chamber inside the furnace cylinder. The immersion tube type direct-fired high-temperature regenerator described. 3. The immersion tube type direct-fired high-temperature regenerator according to claim 1, wherein the side wall of the furnace cylinder is covered with a heat insulating material. 4 A furnace cylinder and a group of solution tubes are arranged inside the main body, a high-temperature gas guide baffle is attached to the side wall of the furnace cylinder, and a guide for dividing the flow path is installed in the side flow path between the main body and the side wall of the furnace cylinder. An immersion tube type direct-fired high-temperature regenerator characterized by the provision of a plate. 5. The immersion tube type direct-fired high-temperature regenerator according to claim 4, wherein the guide plate is provided at least in the side flow path of the boundary area between the co-smooth solution tube and the finned solution tube.