JPS6359066B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a degassing method in a geothermal water heat exchanger.

When river water or the like is heated using geothermal water as a heat source and the heated water is transported to a heating facility or the like, transportation piping and the like are often corroded by oxygen dissolved in the river water. Therefore, in the past, for example, patent application No. 55-28260
As shown in this issue, there is a system that uses steam generated from geothermal water as a heat source to degas heated water. However, in such cases, the steam generated from geothermal water may contain hydrogen sulfide, etc.
It is often unsuitable as steam for degassing.

Therefore, an object of the present invention is to prevent hydrogen sulfide from geothermal water from being contained in heated water after deaeration.

In order to achieve this object, the present invention provides a multi-stage flash heat exchanger that flash-evaporates geothermal water and uses the flash vapor to heat clean water such as river water. The heated clean water and a part of the created hot water from the final stage are led to a deaerator, where the heated clean water is flash-evaporated, and the created hot water is used as a heating source. The created hot water is obtained by degassing and guiding the degassing drain water to the final stage and heating it.

Therefore, since a part of the created hot water after heating is used as a heating source for deaeration, there is no risk that the drain water after deaeration will contain hydrogen sulfide, etc. from geothermal water, and it is clean. It is possible to obtain created hot water.

Embodiments of the present invention will be described below based on the drawings. In FIG. 1, 1 is a multi-stage flash heat exchanger, and adjacent multi-stage flash chambers 2A to 2
A flash section 3 having E and each flash chamber 2
The heat exchange section 5 has heat exchange chambers 4A to 4E communicating with A to 2E. Reference numeral 6 denotes a high-temperature geothermal water supply pipe to the flash section 3, which is connected to the flash chamber 2A, and a geothermal water storage tank 7 is provided along the way. On the other hand, 8 is a low-temperature geothermal water discharge pipe from the flash section 3 to a ring well (not shown), and is connected to the flash chamber 2E.

In the heat exchange section 5, the heat exchange chamber 4A at the last stage on the exit side is an indirect heating stage, and a heat exchange tube 9A is provided inside the heat exchange chamber 4A. Moreover, the heat exchange chambers 4B to 4E other than the final stage are used as direct heating stages, and injection nozzles 10B to 10E are provided therein. A supply pipe line 14 of clean water (river water) 13 from a water intake tank 12 attached to a river 11 etc. is connected to the injection nozzle 10E of the heat exchange chamber 4E.
5. Also, heat exchange room 4B~
The injection nozzles 10B to 10D of 4D are heated water 16C to 16C from the heat exchange chambers 4C to 4E in the previous stage, respectively.
Transfer pipes 17a to 17c of 16E are connected.

18 is a deaerator, which connects the transfer pipe 19 from the heat exchange chamber 4B in the previous stage of the final stage and the heat exchange chamber 4 in the final stage.
A pipe line 20 to the heat exchange tube 9A of A is connected. 21 is an exhaust pipe from the deaerator 18.
A created hot water storage tank 22 is connected to the exit side of the heat exchange tube 9A, and the created hot water storage tank 22 is further provided with a supply pipe 23 that supplies a portion of the created hot water to the deaerator 18. A take-out pipe line 24 for taking out and utilizing the remainder of the created hot water is connected.

The heat exchange chamber 4A serving as an indirect heating stage has a discharge pipe 26 for condensed water 25A in the heat exchange chamber 4A.
A is connected, and this discharge pipe 26A reaches the drain tank 27. The drain tank 27 is configured so that the condensed water 25A flashes into steam therein, and the flash steam is sent via the condenser 15 to the final stage flush chamber 2E through the steam transfer pipe 28 and the drain water 29. Water intake tank 12
A drain water transfer pipe 30 is connected thereto.

In addition, in FIG. 1, 31 is a valve and 32 is a pump.

In the above configuration, high-temperature geothermal water is temporarily stored in the geothermal water storage tank 7 and then sent to the flash section 3, where it evaporates while gradually becoming lower in temperature and pressure as it goes from the flash chamber 2A to the flash chamber 2E. The resulting flash steam is sent to each heat exchange chamber 4A to 4E. In addition, the low-temperature geothermal water that remains without being evaporated is returned to the ring source well through the discharge pipe 8. Assuming that the geothermal water contains hydrogen sulfide, most of this hydrogen sulfide evaporates together with the flash steam in the first stage flash chamber 2A and is sent to the heat exchange chamber 4A, and is therefore sent to the second stage flash chamber 2A. Subsequent flash steam in the flash chambers 2B to 2E contains almost no hydrogen sulfide, and is sent to the heat exchange chambers 4B to 4E.

Clean water 13 from the water intake tank 12 is supplied to the condenser 1
After being heated through the flash chamber 5, it is injected from the injection nozzle 10E into the first stage heat exchange chamber 4E, where it is mixed and heated with flash steam from the flash chamber 2E. As a result, the heated water 1 is heated by the condensed water of the flash steam and the clean water 13.
6E will be generated. This heated water 16E
is injected into the heat exchange chamber 4D from the injection nozzle 10D via the transfer pipe 17c, and thereafter heated water 16D to 16B is generated in the same manner as above. As mentioned above, the flash steam from the flash chambers 2B to 2E contains almost no hydrogen sulfide, and therefore the heated water 16B to 16E is generated in a clean state.

The heated water 16B is sent from the transfer pipe 19 to the deaerator 18, and inside the deaerator 18, the heated water 16B is sent to the created hot water storage tank 2.
The generated hot water from 2 flashes and evaporates, and the heated water 16B is degassed using the steam as a heating source.
Oxygen dissolved in the clean water 13 in the river 11 is extracted from the heated water 16B and released into the atmosphere through the exhaust pipe 21. This makes it possible to prevent corrosion caused by oxygen in the transport pipeline when using the created hot water. The mixed water (drain water) 33 of the heated water 16B after deaeration and the created hot water is sent to the heat exchange tube 9A through the pipe line 20, heated by flash steam from the flash chamber 2A, and becomes created hot water. The hot water is sent to the created hot water storage tank 22. A portion of the produced hot water in the produced hot water storage tank 22 is sent to the deaerator 18 as described above, and the remainder is taken out from the extraction pipe 24 for use.

The flash steam sent from the flash chamber 2A to the heat exchange chamber 4A is condensed by heating the mixed water 33 via the heat exchange tube 9A, and condensed water 5A is generated. As mentioned above, when the geothermal water contains hydrogen sulfide, this hydrogen sulfide reaches the heat exchange chamber 4A together with flash steam and is dissolved in the condensed water 25A. The condensed water 25A in which the hydrogen sulfide content is dissolved is sent to the drain tank 27 from the discharge pipe 26A, and is flash-evaporated in the drain tank 27. At this time, most of the dissolved hydrogen sulfide evaporates together with the flash vapor, is sent to the condenser 15 via the vapor transfer line 28, and is dissolved in a high concentration in the flash vapor condensed in the condenser 15. It is sent to the flash chamber 2E, and then returned to the ring source well (not shown) through the discharge pipe 8. As a result of the above, the drain water 29 remaining in the drain tank 27 has a significantly reduced hydrogen sulfide concentration, and the drain water transfer pipe 3
0 is sent to the water intake tank 12 and used for reducing the amount of clean water 13 and water intake from rivers 11 and the like.

That is, from the drain tank 27 to the capacitor 1
5 is the amount of steam sent to each flash chamber 2A to 2E.
This amount is very small compared to the total amount of flash steam generated in the flash chambers 2A to 2E, and most of the hydrogen sulfide from the geothermal water is contained in this small amount of steam. Most of the flash steam generated is recovered in a clean state through the heat exchange chambers 2B to 2E or the drain tank 27, and is effectively utilized.

In the above embodiment, the method of the present invention is applied to only the heat exchange chamber 4A at the final stage on the exit side of the heat exchange section 5 as an indirect heating stage, and the other thermal heating chambers 4B to 4E as direct heating stages. However, the number of indirect heating stages can be increased or decreased as appropriate depending on the concentration of hydrogen sulfide contained in the geothermal water. Figure 2 shows all heat exchange rooms 4A.
-4E is shown as an example of a joint heating stage,
Heat exchange tubes 9A to 9E provided in heat exchange chambers 4A to 4E, respectively, are connected in series to each other,
The clean water 13 from the water intake tank 12 is heated in stages. It is similar to that shown in FIG. 1 in that the heated water from the heat exchange chamber 4B in the previous stage of the final stage is sent to the deaerator 18, and a part of the created hot water is used as a heat source to degas it.

A drain tank 27 is provided in each heat exchange chamber 4A to 4E.
Discharge pipes 26A-2 for condensed water 25A-25E to
6E is connected. That is, if the concentration of hydrogen sulfide contained in the geothermal water is high and even the condensed water 25E in the heat exchange chamber 4E has a large amount of dissolved hydrogen sulfide, all of the condensed water 25A to 25E should be drained. The hydrogen sulfide is collected in a tank 27, and hydrogen sulfide is evaporated and removed within this drain tank 27. Therefore, a large amount of drain water 29 is generated compared to that shown in FIG. Because it is supplied,
Similar to what is shown in FIG. 1, the retained heat amount is effectively utilized and the amount of water taken from the river 11 etc. is reduced.

As described above, according to the present invention, since a part of the created hot water after heating is used as a heating source for deaeration, the drain water after deaeration contains hydrogen sulfide etc. from the geothermal water. There is no risk of water leaking, and clean generated hot water can be obtained.

[Brief explanation of the drawing]

The drawings show embodiments of the method of the present invention, with FIG. 1 showing a first application example and FIG. 2 a second application example. 1...Multi-stage flash heat exchanger, 3...Flush section, 5...Heat exchange section, 16B-16E...Heated water (heated clean water), 18...Deaerator, 22...
...Created hot water storage tank, 33...Mixed water (drain water).

Claims (1)

[Claims] 1. In a multi-stage flash heat exchanger that flash-evaporates geothermal water and heats clean water such as river water using the flash steam, the heated clean water from the previous stage of the final stage of this multi-stage flash heat exchanger and the final stage A part of the generated hot water is introduced into a deaerator, and the heated clean water is evaporated in the deaerator, and the generated hot water is used as a heating source to degas the drain water. A deaeration method in a geothermal water heat exchanger, characterized in that the created hot water is obtained by guiding the generated hot water to the final stage and heating it.