JPH02191586A - Device for desalting sea water - Google Patents

Abstract

PURPOSE:To obtain inexpensive and good-quality potable water by supplying the warm sea water on the sea surface to a water contact device, such as cooling column for air conditioning, to bring the sea water into contact with the air and to evaporate the same, and then condensing this air via an air fin cooler by the cold waste sea water or the like used for ocean temp. difference power generation. CONSTITUTION:The warm sea water on the sea surface is supplied to to cooling column for air conditioning or the packed column resembling thereto or other gas-water contact device 103 where the sea water is brought into contact with the air and is evaporated under the atm. pressure. This air is condensed by the cold waste sea water used for the ocean temp. difference power generation or in some cases by the particularly pumped up sea water, via the air tin cooler 20, by which the carbon dioxide, oxygen, etc., separated in an evaporator 1 are again absorbed and the inexpensive and goodquality potable water is obtd.

Description

[Detailed description of the invention] (Industrial application field) The present invention is mainly applied to an ocean temperature difference power generation device.

This is a seawater desalination device that condenses water vapor generated from warm seawater to obtain fresh water by making use of the sufficiently low temperature still remaining in the cold seawater used for the initial steaming.

C) Conventional technology and its problems) Conventionally, the mainstream method for seawater desalination plants has been the multistage flash method, but since this method burns fossil fuels in the boiler, there is a risk of increasing the carbon dioxide concentration in the atmosphere. This is unfavorable for the global environment. Further, the equipment for this purpose is a pressure vessel or a solid-walled vessel, and is made of expensive materials that are resistant to seawater corrosion, making it extremely expensive.

Furthermore, the cost of prepared fresh water is not very cheap.

- There are two types of ocean thermal power generation: the direct method, in which warm seawater is directly evaporated with true nitrogen to drive a turbine, and the exhaust gas is condensed with cold seawater, and the indirect method, which uses a refrigerant. In the direct method, fresh water is produced at the same time as electricity, but it has not been put to practical use because the turbine would be too large. The indirect method has almost every prospect of practical application, but it cannot produce fresh water.

(Purpose of the invention) In addition to obtaining inexpensive electricity, ocean thermal conversion power generation can also be used to reduce abnormally high temperatures at the sea surface (El Niño phenomenon). It has the great advantage of relaxing, nutrient-rich seawater from the deep seabed is pumped up and mixed with oxygen-rich coastal water, allowing plankton to form there and forming a rapid zone.

Moreover, the temperature of cold seawater after being used for power generation is still sufficiently lower than the seawater temperature at the sea surface, so the temperature difference can be used to create fresh water.

For example, if the temperature difference between warm seawater and expelled seawater is 16°C, a three- or four-stage multistage flash evaporation method can be applied. However, since the temperature is low, the device requires a high vacuum, making the equipment expensive.

The amount of seawater used for ocean thermal power generation is enormous, and the amount of energy that can be used even with discharged seawater is enormous. Even if the energy efficiency is low, it is possible to produce fresh water at low cost using a plant with low equipment costs. This is because energy sources can be considered free.

The present inventor was able to reach a goal of developing a high-performance heat exchanger suitable for the ocean temperature difference [1C], and in view of the recent public opinion regarding the deterioration of the global environment, desalination We considered creating freshwater from seawater at a much lower cost than before by installing a BRADT, and were able to come up with a plan.

(Structure of the Invention) That is, according to the present invention, warm seawater at the sea surface is supplied to an all-control cooling tower, a similar packed tower, or other air-water contact device, and brought into contact with air under two pressures to evaporate it. This air is then condensed via an air fin cooler with cold waste seawater used for ocean thermal power generation or, in some cases, pumped-up seawater, to re-adsorb carbon dioxide, oxygen, etc. separated in the evaporator. Thus, a seawater desalination device is obtained, which is characterized in that it can obtain inexpensive and high-quality drinking water.

The present invention further provides a hollow shaft that passes through end plates at both ends of the cylindrical evaporator, and a plurality of disk packings made of a porous material with a rough surface such as open-cell foamed glass, foamed resin, or sintered granules. is sandwiched and fixed in the middle of each, and seawater is supplied from one end of the hollow shaft through a rotary joint, and is press-fitted into the disc through a small hole drilled around the hollow shaft. The other end of the evaporator is connected to a motor with a speed reducer to slowly rotate it, and the bottom of the evaporator is filled with seawater to an appropriate level so that a part of the disc is immersed in the seawater. The method is characterized by being provided with an evaporator that supplies water from both the hollow shaft and the periphery of the disc, and circulates air to promote evaporation from the rough surface of the disc and prevent scale from forming. The present invention provides a seawater desalination device.

Rainfall phenomena in the natural world are mostly nothing but desalination of seawater, but their essence is evaporation and condensation in the air. Therefore, these phenomena take place under atmospheric pressure.

As mentioned above, the present invention focuses on the fact that the cold seawater used for ocean temperature difference is still at a considerably low temperature, and uses a cooling tower for cooling the warm seawater at the sea surface, or a similar packed tower, or Furthermore, most of the This is a seawater desalination device that can produce fresh water at low cost using free energy.

Next, the apparatus of the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a longitudinal cross-sectional view of an embodiment of the apparatus of the present invention, in which 1 is an evaporator, 2 is a condenser, and 3 is a blower. In the evaporator 1, 101 is a seawater inlet, 102 is a sprinkler, and 103 is a kind of packed tower corresponding to the inside of a cooling tower. There are many known devices designed to provide as large an evaporation area as possible with as little pressure loss as possible, but among these, one should choose one that entrains as few droplets as possible, and if possible, one that does not entrain droplets at all. Since it is desirable and τ, such an example will be explained below.

Reference numeral 104 is an air inlet, and this air comes into contact with seawater falling from the sublime/clarifier in the packed tower 103 and becomes saturated with moisture. ios is a demister 106 is a blowdown outlet.

In the condenser 2, 201 is a group of fins that cause condensation, and these are penetrated by a group of tubes 202, and the cold seawater in the group of tubes 202 flows from the evaporator l to the blower 3.
The moist air introduced by &C cools and causes moisture to condense.

The condensed water accumulates at the bottom of the condenser 2 and is taken out from the outlet 203 as fresh water. 204 is an air outlet. This air is cooled by the cold seawater and is very cold, so it is sometimes used for air conditioning, but the amount of cold air is large, and it is said to be effective in cooling the surrounding area. considered,
Even if it is limited to areas with dry, hot desert climates, it is thought that it will improve and become part of desert greening.

FIG. 2 is a longitudinal cross-sectional view of a different 5N embodiment of the present invention, showing a cross-section f in the longitudinal direction of an evaporator without the risk of entrainment of droplets, and FIG. 3 shows a cross-section in a direction perpendicular thereto.

In the evaporator l in Figure 2, the seawater inlets are 101A and l.
It is divided into two parts: 0IB. The main body of the evaporator 1 consists of a horizontal cylinder, and sealed bearings 107 are provided on the head plates at both ends, thereby supporting a shaft 108 of the inner nitrogen. The left end of the inner shaft 108 is connected to one seawater inlet 101A via a sealed joint 109, and the right end is connected to a motor 1010 with a speed reducer, which rotates the shaft at a slow rate of τ. .

The 10g shaft is made of open-cell foamed glass and foamed resin.

A large number of disks 1011 made of a porous material such as V8 granules are fixed coaxially with the shaft 108 through gaskets 1012 and rotated together with the shaft 108. This disk 1011 is partially immersed in the seawater that has accumulated at a constant level at the bottom of the evaporator 1 body, and rotates while sucking up the seawater by its capillary action. New seawater is replenished to the bottom of the evaporator 1 body from the seawater inlet 101B, and some of it is gradually discharged from the outlet 106 to prevent concentration due to evaporation. This corresponds to boiler blowdown. Seawater entering the shaft 108 from the inlet 101A flows through the shaft 108.
It is pushed into the circle [1011] through a hole 1013 made around the disk, oozes out onto the surface of the disk 10110, spreads around it, and evaporates. The area around the center of the disk 1011 is constantly washed with fresh seawater, so no scale is attached. Disk 1011
As the area around the evaporator 1 is rotated, it is immersed in the seawater at the bottom of the evaporator 1 and washed successively, so that scale adhesion is also prevented. 104.1014 are air inlets and outlets.

Although this structure is more expensive than existing cooling towers, it does not cause droplet agitation, the Demi-105 can be omitted, the pressure loss of the blower is reduced, and
Very pure fresh water can be obtained. The main body of the evaporator I is naturally cylindrical to prevent air from bypassing other than the disk surface, and the gap between the disks is appropriately small to increase the air flow rate and promote evaporation. In addition, in the device of the present invention, non-condensable gases such as oxygen and carbon dioxide generated in the evaporator 1 are also transported along with the water vapor and are absorbed again after condensation, making it suitable for drinking. This is preferable.

The main purpose of the device of the present invention is to reuse the cold seawater used for ocean temperature difference power generation, but if cold seawater can be obtained easily and inexpensively, it is of course possible to pump it up from @Nakkai using power. It is. For example, if wind power, wave power, or another type of cheap or lean energy other than ocean thermal power generation becomes available, it is of course possible to use that energy to directly pump up seawater.

(Effects of the Invention) The present invention has the following effects (1) by adopting the above 41m configuration.
) High purity freshwater can be obtained at low cost.

(2) The obtained fresh water contains oxygen that has evaporated from seawater,
Since carbon dioxide gas etc. are reabsorbed, this water is suitable for drinking water.

(3) A large amount of cold air can be obtained.

[Brief explanation of the drawing]

1 is a longitudinal cross-sectional view of one embodiment of the apparatus of the present invention, FIG. 2 is a longitudinal cross-sectional view of a different embodiment of the apparatus of the present invention, and FIG. 3 is a cross-sectional view of FIG. 2. In the figure: 1-111 evaporator 2-111 condenser 3-111 blower 101, 101 people, l0IB----1 seawater inlet 10
2---Sprinkler 103---1 Packed column 104---1 Air inlet 105---Demister 106---Blowdown outlet 202---1- Sealed bearing hollow shaft sealed type Joint fin group Fresh water groove outlet Air outlet Motor circle with reducer Plate seal hole Air outlet

Claims (2)

[Claims] (1) Warm seawater at the sea surface is supplied to an air conditioning cooling tower, similar packed tower, or other air-water contact device, and is brought into contact with air under atmospheric pressure to evaporate, and this air is used for ocean thermal power generation. The carbon dioxide, oxygen, etc. separated in the evaporator are reabsorbed by condensing the cooled discharged seawater or, in some cases, pumped-up cold seawater through an air fin cooler, thereby producing inexpensive, high-quality drinking water. A seawater desalination device characterized by: (2) A large number of disks made of porous materials with rough surfaces such as open-cell foamed glass, foamed resin, and sintered granules are packed on one hollow shaft that passes through the head plates at both ends of the cylindrical evaporator. Seawater is supplied from one end of the hollow shaft via a rotary joint, and is press-fitted into the disc through a small hole drilled around the hollow shaft to coat the surface of the disc. The other end of the evaporator is connected to a motor with a speed reducer to slowly rotate it, and seawater is collected at an appropriate level at the bottom of the evaporator so that a part of the disk is immersed in the seawater. Seawater is provided with an evaporator that supplies air from both the hollow shaft and the periphery of the disk, circulates air to promote evaporation from the rough surface of the disk, and prevents scale from forming. desalination equipment.