JPS632203B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a return device for low-quality produced water in a multi-stage flash evaporation type seawater desalination water production system.

Conventionally, in this type of fresh water generating apparatus, when the quality of produced water deteriorates in one of the many stages, it has been necessary to stop the operation of the entire fresh water generating apparatus in order to remove the low quality water. Therefore, there is a significant loss in operating costs due to stopping and restarting the freshwater generating equipment, and countermeasures have been desired.

This invention was made in response to the above-mentioned needs, and it is possible to extract low-quality water and return it to the circulating brine without stopping the operation of the fresh water production equipment, allowing for continued production of fresh water. The purpose is to provide a return device for

The low water quality produced water return device according to the present invention has a collection channel connected to the precipitation port provided at each stage on the bottom surface of the condensed water receiving tray having a precipitation port, and a weir is provided in the collection channel in the direction of the path length. The collection channel is constructed by a weir, with a water receiving section that receives the runoff from the rain outlet and collects it at each stage, and a water inlet in the partition wall of each stage that allows water to flow over the weir from the water receiving section. In each stage, a low-quality water return pipe with a valve is installed from the water receiving part to the brine evaporation zone, and at each stage, the water generated by passing the produced water through the water inlet is divided into two parts. A steam duct is provided to convey steam from the collection channel to the condensation zone.

Examples of the present invention will be described in detail below.

In FIGS. 1 to 3, a brine circulation type freshwater generator 1 is divided into multiple stages in the length direction by a large number of vertical partition walls 2. As shown in FIGS. An orifice 3 for flushing is provided at the lower end of each partition wall 2. Each stage is divided into a lower evaporation zone 5 and an upper condensation zone 6 by a tray 4 for receiving condensed water, and both zones 5, 6 are separated by a steam riser 8 having a mist removal member 7. It is communicated. At one end of the freshwater generating apparatus 1, that is, at the left end of the apparatus 1 in FIG.
A brine supply port 9 leading to the evaporation zone 5b is provided at the other end, and an evaporation residual brine discharge port 10 leading to the final stage evaporation zone 5b is provided at the other end. The evaporation residual brine is then returned to the supply port 9 from the discharge port 10 via the outside of the apparatus, and is again circulated to the evaporation zone 5. The required amount of concentrated brine is withdrawn from the circuit. A seawater replenishment port 11 is provided at the discharge port 10. As shown in FIG. 3, each condensation zone 6 is provided with a condensing heat transfer tube bundle 13 bound by a plurality of support plates 12. Each support plate 12 has a small gap 14 between it and the tray 4 for water passage.

At one side of the freshwater generating device 1, that is, at the left end of the device 1 in FIG.
A collection channel 16 is provided in the lower surface of the tray 4 in the length direction thereof, leading to a rain outlet 15 at each stage. A weir 17 is provided in the collection waterway 16 in the length direction, and the weir 17 allows the collection waterway 16 to
is divided into a water receiving section 18 and a water guiding section 19. A rain outlet 15 faces the water receiving part 18 from above in each stage, and the water receiving part 18 receives the flowing water from the rain mouth 15 and stores it in each stage. A water passage port 20 is provided in each of the partition walls 2 at the water guide portion 19 . Further, a produced water outlet 21 communicating with the water guide section 19 is provided at one side of the other end of the fresh water generator 1 . The water guide section 19 guides water from the water receiving section 18 over the weir to the produced water outlet 21. A low-quality water return pipe 22 is disposed on one side of the fresh water generator 1 and extends from the water receiving portion 18 to the evaporation zone 5 via the outside of the device. A valve 23 is provided on the outer part of the tube 22.

On one side of the fresh water generator 1, the steam rising path 8 of each stage is connected from a collection channel 16 to a condensation zone 6.
A steam duct 24 is provided for sending steam to.
The steam duct 24 has both side walls 25 formed by extending both sides of the collection waterway 16 into the steam ascending passage 8, an inclined top wall 26, and a side wall on one end side of the steam ascending passage 8 between the pair of side walls 25. It consists of a vent hole 28 opened in 27.

In the freshwater generator 1 having the above configuration, the pressure at each stage is gradually reduced from the brine supply end to the discharge end, and all valves 23 at each stage are closed. Thermal brine heated by the steam heater is supplied to the evaporation zone 5 from the supply port 9, and flash-evaporated each time it passes sequentially through the orifices 3 of each stage under reduced pressure. The generated water vapor enters the condensation zone 6 via the mist removal member 7 of the steam ascending path 8 and is condensed. The condensed water drips onto the tray 4, flows on the tray 10 in the direction of the rain outlet 15, and is collected, and the collected water flows down from the rain outlet 15 at each stage to the water receiving part 18 of the collection channel 16 and accumulates therein.
At each stage, the produced water that has filled the water receiving section 18 overflows over the weir 17 into the water guiding section 19 and flows to the produced water outlet 21 through the water inlet 20. In this way, produced fresh water is taken out from the take-out port 21.

If the quality of the produced water deteriorates in a certain stage among the many stages, the valve 23 of that stage is opened and the low quality water is returned to the evaporation zone 5 through the return pipe 22.
and join the circulating brine. In the other stages, the valve 23 remains closed.

The produced water flowing through the water guide section 19 is passed through the water passage ports 2 of each stage.
Each time it passes through zero, it self-evaporates due to the vacuum flush and generates steam. The resulting steam is sent to the condensation zone 6 through the steam duct 24. Therefore, this vapor does not mix with unrefined brine vapor that has not passed through the mist removal member 7.

As described above, according to the present invention, the tray 4
Collection waterway 16 leading to rain outlet 15 of each stage on the bottom surface of
is provided in the collection waterway 16 and the water receiving part 18
A weir 17 is provided to divide the water into the water conveyance section 19, and a low quality water return pipe 22 with a valve 23 is arranged from the water receiving section 18 to the evaporation zone 5. In this case, only the valve 23 of that stage can be opened to allow the low quality water to flow down to the evaporation zone 5 via the return pipe 22 and join the circulating brine. Therefore, in other stages where the quality of the produced water has not deteriorated, fresh water production can be continued without closing the valve 23.
Therefore, there is no need to stop the entire freshwater generating apparatus 1, and it is possible to eliminate operating cost losses due to stopping and restarting the apparatus. In addition, since a steam duct 24 is provided at each stage to send steam from the collection waterway 16 to the condensation zone 6, the produced water is transferred to the water conduit 1.
The purified steam produced by self-evaporation when passing through the water inlet 20 of 9 is sent to the condensation zone 6 without mixing with the unpurified brine vapor produced in the evaporation zone 5. Therefore, there is no risk of degrading the quality of the produced water.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan view of a freshwater generator, and FIG.
3 is an enlarged cross-sectional view along the - line in FIG. 2, FIG. 4 is an enlarged view of the main part of FIG. 2, and FIG. 6 is a sectional view taken along the line - in FIG. 4. FIG. 1... Water generator, 2... Partition wall, 3... Orifice, 4... Tray, 5... Evaporation zone, 6...
Condensation zone, 7...Mist removal member, 8...Steam rising path, 9...Supply port, 10...Drain port, 11...
... Seawater supply port, 12 ... Support plate, 13 ... Heat exchanger tube bundle, 14 ... Small gap, 15 ... Downfall port, 16 ...
Collection channel, 17... Weir, 18... Water receiving part, 19...
...Water conduction section, 20...Water inlet, 21...Produced water outlet, 22...Low water quality water return pipe, 23...Valve,
24...Steam duct, 25...Side wall, 26...Top wall, 27...Side wall, 8...Vent.

Claims (1)

[Claims] 1. A collection waterway 16 is provided at each level on the lower surface of the condensed water receiving tray 4 having a rainwater outlet 15 and is connected to the rainwater outlet 15. A weir 17 is provided in the collection waterway 16 in the direction of the road length, and a weir 17 is provided in the weir 17. Yotsute collection waterway 16
There is a water receiving part 18 which receives the flowing water from the rain outlet 15 and collects it in each stage, and the water flowing over the weir from the water receiving part 18 is passed through the water inlet 20 made in the partition wall 2 of each stage to produce water. A low water quality water return pipe 22 with a valve 23 is connected from the water receiving part 18 to the brine evaporation zone 5 at each stage.
A return device for low water quality produced water in a fresh water production device, in which a steam duct 24 is provided at each stage to send steam generated when the produced water passes through a water inlet 20 from a collection waterway 16 to a condensation zone 6.