JPS6313116B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an immersion tube-type direct-fired high-temperature regenerator ( (hereinafter referred to as a regenerator).

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.
, solution pipes 12 and 13 built in the combustion gas downstream portion of the furnace tube, a high-temperature combustion gas guide baffle 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. and an overflow pipe 16 for discharging concentrated liquid. 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
After being heated and concentrated in the furnace tube 11 and the solution tubes 12 and 13, it is discharged from the overflow tube 16. In such a regenerator, the liquid temperature is generally heated to about 160℃,
Concentrate the LiBr solution so that the LiBr concentration is 60-65%. Figure 3 is a graph showing the relationship between the temperature of LiBr solution and the corrosion rate of metal, where a and b are
c indicates the case where the LiBr solution with the LiBr concentration of 65% and 62% is in the stopped state, and the case where the LiBr solution with the LiBr concentration of 65% is in the fluid state. From this figure, LiBr solution with LiBr concentration of 60 to 65% is especially in the stopped state.
It is clear that the corrosion rate of metal increases rapidly when the temperature reaches 165 to 175℃, and therefore, when the liquid temperature reaches 160℃
As described above, in a regenerator where the LiBr concentration is 60 to 65%, if the liquid flow in the vessel stagnates, significant corrosion will occur in the stagnation area.

In the past, corrosion caused by this LiBr solution occurred particularly at the rear of the solution tube group, and many accidents occurred when solution tubes were opened in this area. Therefore, in order to investigate the cause of this corrosion of the solution tube, the present inventors observed the liquid flow state, which is closely related to corrosion, using a three-dimensional gas bubble model.
As a result, in the longitudinal direction of the regenerator main body 1,
As shown in FIG. 1, the liquid level of the LiBr solution 21 is high on the furnace section 17 side of the furnace tube 11, and a gentle clockwise circulation flow occurs.
As shown in Figure 4, the liquid level is high on both sides and strong liquid circulation occurs in the clockwise direction, and at the solution tube groups 12 and 13, the liquid level is at the center as shown in Figure 5. It was found that high and clockwise and counterclockwise liquid circulation occurs on the side. The difference ΔH between the high liquid level on the furnace section 17 side and the low liquid level at the rear of the solution tube group, shown in FIG. 1, is due to the fact that the amount of evaporation in the solution tube group is larger than that in the furnace section. and increases as the heat load increases. In this case, the liquid level on the side of the furnace section 17 is kept constant because the overflow pipe 16 for taking out the concentrated liquid is provided at a predetermined height position above the furnace section, but the liquid level on the side of the solution tube group is kept constant. The liquid level decreases as the heat load increases. Therefore, when the heat load increases and the liquid level difference ΔH increases, the upper surface of the furnace cylinder becomes exposed, as can be seen from the liquid level indicated by the dotted line in FIG. At that time, at the rear of the solution tube group,
As shown in FIG. 6, the liquid circulation is cut off on the left side. As a result, a liquid stagnation area 90 is generated at the lower left side. The liquid stagnation area 90 causes corrosion at the rear of the solution tube group in an actual machine.

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

An object of the present invention is to reduce the liquid level in the rear region of the solution tube group to a predetermined level in an immersion tube type direct-fired high-temperature regenerator equipped with a furnace tube and a group of solution tubes built in a downstream portion of the combustion gas tube group of the furnace tube. This has been achieved by the present invention, which is provided with a liquid level adjusting means for maintaining the liquid level.

An embodiment of the present invention will be described below with reference to FIG.

The immersion tube type direct-fired high-temperature regenerator according to this embodiment differs from the conventional one shown in FIG. 1 in the arrangement position of the overflow tube for discharging the concentrated LiBr solution. In this embodiment, as shown in FIG.
is the solution tube 1 in the rear area of the solution tube group, that is, on the side of the chimney 15.
3 or between the solution pipe 13 and the chimney 15, and its opening is located 0 to 100 mm higher than the upper surface of the furnace tube 11. Therefore,
The liquid level in the rear region of the solution tube group, that is, the lowest liquid level in the regenerator can always be maintained at a level above the upper surface of the furnace tube 11. Therefore, due to variations in heat load,
Even if the difference ΔH between the liquid level on the furnace section 17 side and the liquid level on the solution tube groups 12 and 13 side changes, the entire area of the furnace tube 11
Since it is immersed in the LiBr solution 21, a stagnation area of the LiBr solution due to insufficient liquid level does not occur. the result,
Corrosion due to LiBr solution stagnation does not occur.

In this embodiment, a very simple overflow pipe 23 was used as the liquid level adjusting means, but other means may be used as long as the liquid level can be maintained at a predetermined level as described above. .

As explained above, the present invention includes a liquid level adjusting means for maintaining the liquid level in the rear area of the solution tube group built in the downstream area of the combustion gas of the furnace cylinder at a predetermined level, so that the liquid level generated in the regenerator is It is now possible to eliminate the liquid stagnation area due to liquid shortage caused by the liquid level difference between the furnace part and the rear area of the solution tube group, and prevents not only corrosion at the rear of the solution tube group due to liquid stagnation but also corrosion throughout the solution tube group. It has the effect of preventing

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal cross-sectional views of conventional regenerators and -
A cross-sectional view along the line, Figure 3 shows the concentration of LiBr solution,
Figures 4, 5, and 6 are diagrams showing the relationship between temperature, flow state, and corrosion rate of metal, respectively.
FIG. 7 is a diagram cut along the line, - line, - line, showing the regenerator according to the embodiment of the present invention.
FIG. 3 is a diagram showing the flow state of a LiBr solution. 11... Furnace tube, 12, 13... Solution tube group, 23
...Overflow pipe.

Claims (1)

[Scope of Claims] 1. In an immersion tube type direct-fired high-temperature regenerator equipped with a furnace cylinder and a group of solution tubes built in a downstream part of the combustion gas tube, the liquid level in the area behind the group of solution tubes is maintained at a predetermined level. An immersion tube type direct-fired high-temperature regenerator characterized by being provided with a liquid level adjustment means for maintaining the liquid level. 2. The immersion tube type direct-fired high-temperature regenerator according to claim 1, wherein the liquid level adjusting means is a liquid overflow pipe provided in the rear region of the solution tube group.