KR100904308B1 - Apparatus for taking fresh water from sea water using solar heat - Google Patents

Abstract

A low energy apparatus for desalination by using solar heat is provided to improve desalination efficiency and to decrease installation and maintenance costs by evaporating seawater naturally in an evaporator by using solar heat. A low energy apparatus(10) for desalination by using solar heat includes an evaporation unit(20) having a plurality of evaporators(41,42) and a heating unit having a storage tank, a first heat exchanger(67), a second heat exchanger(87), a solar panel(60), and a pump(85). A plurality of evaporators are connected by a connecting pipe(56) and arranged to multi-stage. The seawater is flowed in a first evaporator(30) through a seawater intake pipe(15). A recycle pipe(61,63) having a valve(62,64) connects the solar panel and the first heat exchanger. An inlet of the second heat exchanger is connected on a seawater tank(81). The pump and the valve are installed on the seawater tank. An expansion tank(73) is installed on the top of the storage tank. A water supply pipe(75) is connected on the top of the expansion tank.

Description

Low energy desalination device using solar heat {Apparatus for taking fresh water from sea water using solar heat}

The present invention relates to a low-energy desalination apparatus using solar heat, and more particularly, in a desalination apparatus using a natural evaporation method of naturally evaporating seawater to obtain fresh water, energy is reduced by preheating seawater using solar heat before natural evaporation. The present invention relates to a desalination apparatus having high desalination efficiency.

In general, in areas with low rainfall, areas where water supply is difficult to supply, or areas where water resources such as dam facilities are lacking by rivers, desalination systems have been introduced to supply various types of living or industrial water by desalination of seawater. It is used.

In such desalination apparatus, the reverse osmosis membrane method extracts fresh water by applying a reverse osmosis pressure higher than the osmotic pressure with a semi-permeable membrane in between, or by flowing sea water through a cation exchange membrane and an anion exchange membrane disposed alternately between two electrodes. Electrolysis methods for separating and removing ions in water have been mainly used.

However, the desalination system using the reverse osmosis membrane system is not only complicated in its facilities, but also requires a high level of skill in the treatment of seawater. There was a problem in that the cost burden is large, and despite such an expensive facility, the desalination efficiency is very low, so there is a problem that is not suitable for mass production of fresh water.

In the case of the desalination system using the electrolysis method as well as the reverse osmosis membrane method, the use of energy and maintenance of the facility is not only excessive cost, but also had a problem that requires a very large site when installing the desalination apparatus.

In addition, unlike the reverse osmosis membrane method or the electrolysis method as described above, desalination systems using a multistage flash (MSF) evaporation method are known to obtain fresh water by evaporating seawater. By injecting superheated seawater (approximately 90 to 110 ° C) into a series of pipes, the superheated seawater evaporates itself along a series of pipes to generate water vapor. At the same time, the condensed water vapor used to heat the seawater can produce fresh water.

However, the desalination system using the conventional multi-stage flash evaporation method also consumes a large amount of fuel to overheat the seawater flowing into the pipe at about 90 to 110 ° C., which requires a lot of expenses for the operation of the desalination system, thereby producing fresh water. Since the unit price increases, there is a problem that the economic efficiency is lowered.

The present invention has been made to improve the above problems, and an object thereof is to provide an energy-saving desalination apparatus that can obtain fresh water by evaporating seawater using solar heat as a heating source so that installation cost and maintenance cost are low. .

Another object of the present invention is to provide a desalination apparatus using a natural evaporation method, by using sea-friendly natural energy to heat the seawater in advance to enter the evaporator to greatly improve the desalination treatment efficiency.

Low energy desalination apparatus using solar heat of the present invention for achieving the above object in the desalination apparatus to remove salt by naturally evaporating sea water by solar heat, seawater flow path flowing through the seawater introduced from the seawater inlet pipe is formed therein A body having an upper portion open to expose the seawater flow passage upward, a roof of a translucent material formed to be inclined on the upper portion of the main body to cover the seawater flow passage, and seawater flowing through the seawater flow passage by the solar heat to be evaporated from the roof; An evaporation unit including at least one evaporator having a fresh water collection pipe installed inside the main body so that condensed fresh water flows down and is collected; heating means for heating sea water flowing into the sea water inlet pipe using natural energy; It is characterized by including.

The heating means includes a first heat exchanger for storing water therein, a first heat exchanger installed at an inner lower portion of the heat storage tank, and discharging heat to the water while circulating a first heat exchange medium absorbing solar heat from a solar heat collecting plate, and the heat storage A second heat exchanger installed at an inner upper portion of the tank and connected to a seawater intake pipe extending from a seawater storage tank, and the other end connected to the seawater inflow pipe, and absorbing heat from the water while seawater flows inside the seawater intake pipe; It is characterized in that it is provided with a pump for transferring sea water.

The heating means includes a boiler, a third heat exchanger circulating and the water heated in the boiler and installed between the first and second heat exchangers and dissipating heat into the water, and a temperature sensor installed inside the heat storage tank. And a controller for operating the boiler when the temperature sensed by the temperature sensor is lower than or equal to a predetermined temperature. The evaporation unit is formed by supporting the evaporator in a frame and arranged in multiple stages, and the frame is supported on the ground. A rectangular base frame, a first horizontal frame spaced apart from the base frame, and a second horizontal frame spaced apart from the first horizontal frame; Each of which is vertically formed at and having a vertical frame for fixing the first and second horizontal frames; The evaporation unit is characterized in that it further comprises a connector interconnecting the respective evaporator is installed on the base frame and the first and second horizontal frame.

As described above, according to the desalination apparatus of the present invention, seawater is naturally evaporated in an evaporator to prepare fresh water, but by heating the seawater in advance by solar heat and introducing the evaporator into the evaporator, the installation cost and maintenance cost are low, and the desalination efficiency is high. High offers the advantage.

In addition, using natural energy such as solar heat as an energy source for heating seawater flowing into the evaporator, it is eco-friendly and does not cost energy generation separately.

In addition, when solar heat is not available or solar heat is insufficient, a stable desalination system can be constructed because the boiler heats seawater using an auxiliary heat source.

Hereinafter, a low energy desalination apparatus using solar heat according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

1 is a schematic view showing a desalination apparatus according to an embodiment of the present invention, Figure 2 is a perspective view showing a multi-stage connected evaporator applied to the desalination apparatus of Figure 1, Figure 3 is a desalination of Figure 1 Some cutaway perspective views showing the interior of the evaporator applied to the device.

1 to 3, the desalination apparatus 10 of the present invention greatly evaporates seawater, and an evaporation unit having a plurality of evaporators in which fresh water is generated and a seawater flowing into the evaporator are heated using natural energy. Heating means is provided.

In the illustrated example, the evaporator unit 20 is shown in which a plurality of evaporators are connected by connecting tubes 56 and arranged in multiple stages. On the contrary, it is a matter of course that a small capacity desalination apparatus using only one evaporator may be implemented without placing the evaporator in multiple stages.

The evaporation unit 20 shows a state in which nine evaporators 30 (41 to 48) are disposed in the frames 50, 51, 53 and 55 as shown in FIG. The frame is horizontally installed between the base frame 50 supported on the ground, the vertical frame 51 formed vertically at both edges of the base frame 50, and both vertical frames 51, and the base frame 50. It is composed of the first and second horizontal frame (53, 55) formed side by side spaced apart above. The frame may be of concrete or steel structure.

In the base frame 50 and the first and second frames 53 and 55, three evaporators are disposed transversely, so that a total of nine evaporators are installed in the frame. The evaporators disposed in the base frame and the first and second frames are connected by connecting tubes 56 in the longitudinal direction to form a continuous passage therein. That is, three branch pipes 16 branched from the seawater inlet pipe 15 are connected to the first, fourth, and seventh evaporators 30, 43, 46, respectively. The first evaporator 30 installed in the second frame 55 is connected to the second evaporator 41 installed in the first frame 53 at the rear side, and is connected to the second evaporator 41 and the base frame 50. The installed third evaporator 42 is connected at the front side. In addition, the fourth, fifth, sixth evaporators 43, 44, 45 are also connected in the same manner as above, and the seventh, eighth, ninth evaporators 46, 47, 48 are also connected in the same manner. . Although the third and sixth and ninth evaporators 42, 45 and 48 are not shown in Fig. 2, they are connected to each other by a connecting tube at the rear side so that the concentrated seawater is finally discharged through the seawater discharge pipe 23. Then, the fresh water is finally discharged through the fresh water discharge pipe (25).

Unlike the above description, three evaporators respectively installed on the second and first horizontal frames and the base frame are laterally connected to each other by a connecting tube, and the seventh evaporator 46 and the eighth evaporator 47 are connected to the rear tube. The second evaporator 41 and the third evaporator 42 are connected to the connecting pipe from the front to the rear of the ninth evaporator 48, the seawater discharge pipe 23 and the fresh water discharge pipe 25 is connected and concentrated It may have a batch structure in which seawater and fresh water are discharged. In addition, the number and connection structure of the evaporator may be changed in various ways.

Since each evaporator constituting the evaporation unit 20 has the same configuration and function, only the first evaporator 30 will be described by way of example.

As shown in FIG. 3, the first evaporator 30 includes a main body 31, a roof 35, and a fresh water collection pipe 37.

The main body 31 has a bottom 32 and a wall 33 formed vertically at all four edges of the bottom 32. Therefore, the main body 31 has a tubular structure with an open top, and an empty space inside the main body 31 is used as the seawater channel 34. That is, in the illustrated example, the seawater flowing through the seawater inlet pipe 15 flows along the bottom of the main body 31.

And the roof 35 is installed in the open upper part of the main body 31. The roof 35 extends upward from the upper end of the left / right walls 33 of the main body 31, but is formed to be inclined to be in contact with each other. The material of the roof 35 uses a light-transmitting material so that external sunlight can be introduced into the body 31. For example, transparent glass, acrylic resin, vinyl, or the like may be used. If vinyl is used, the skeleton can be formed from pipes to maintain the shape of the roof.

The fresh water collection pipe 37 in which the water evaporated from the sea water is condensed and collected is installed inside the main body. Freshwater collection pipes 37 are respectively provided on the inner side surfaces of the left and right walls 33 of the main body and are continuously formed along the longitudinal direction of the main body 31. In this case, the freshwater collection pipe 37 is installed to be spaced upwardly from the bottom 32 of the main body so as not to interfere with the flow of seawater. The freshwater collection pipe 37 forms a freshwater flow path 38 through which fresh water is circulated by fixing a metal plate bent in a b shape to a wall 33 of the main body by welding or bonding. Of course, it is possible to use a rectangular or circular pipe having a hollow inside and an open top thereof by fixing it to the wall 33.

Since the evaporation area of the seawater is reduced when the freshwater flow path 38 formed by the freshwater collecting pipe 37 is large, it is preferable to form the freshwater collecting pipe 37 to have a minimum cross-sectional area within the desalination capacity limit. .

And the outer side of the main body 31 to surround the conventional heat insulating member 39 to prevent the cooling of the inside of the main body 31. As the heat insulating member 39, urethane foamed resin, nonwoven fabric, styrofoam may be used, and in addition, a typical heat insulating member may be used.

When the seawater is introduced into the first evaporator 30 configured as described above through the seawater inlet pipe 15, seawater flows along the bottom of the main body 31. And the inside of the main body 31 rises in temperature by solar heat, and the moisture in seawater will evaporate. The evaporated water is brought into contact with the inner surface of the roof 35 to be condensed, and the fresh water condensed in the form of a water droplet flows down the inclined surface of the roof 35 and is collected into the fresh water collection pipe 37. The fresh water thus generated flows along the freshwater flow path 38 and is finally discharged through the freshwater discharge pipe 25.

Although not shown, a sprinkler is installed on the upper part of the roof 35 to spray cold seawater on the upper part of the roof 35 to lower the temperature of the roof 35 so that the evaporated water can be easily condensed. In addition, a thin plate-like flow path may be formed in the roof 35 so that seawater having a low temperature flows. In this case, the seawater introduced into the roof 35 takes heat away from the roof while heat-exchanging with the roof 35, and the temperature is increased. In this way, the temperature of the seawater is increased by the inflow of the seawater into the body 31 through the seawater inlet pipe 15 to improve the freshwater treatment efficiency.

In addition, a heater (not shown) is installed between the outer circumferential surface of the main body 31 and the heat insulating member 39 at a predetermined interval so that the seawater flowing through the main body 31 can be maintained while maintaining a constant temperature. In addition, a pipe (not shown) is provided along the seawater passage 34 of the main body 31, and fine holes are formed in the pipe. In addition, the pipe heated by an external boiler may be introduced into the pipe to facilitate evaporation while the seawater is vibrated and heated by the steam discharged into the seawater through the hole of the pipe.

On the other hand, when multiple evaporators are connected in multiple stages, the connection pipe is a seawater connecting pipe 57 interconnecting the seawater flow paths of each evaporator as shown in FIG. It consists of a fresh water connecting pipe (59) to connect.

As described above, the seawater is introduced into the evaporator through the seawater inlet pipe, and the present invention heats the seawater introduced through the seawater inlet pipe to a predetermined temperature to increase the amount of evaporation by introducing the evaporator into the evaporator to increase the freshwater treatment efficiency. Have the means.

Preferably, the heating means uses natural energy that is eco-friendly and does not cost energy. In the illustrated example, solar energy is used as energy for heating seawater. In addition, the seawater can be heated by the generated electric energy using tidal or wind power.

Solar heating means applied to an embodiment of the present invention is the heat storage tank 70, the first heat exchanger 67, the second heat exchanger 87, the heat collecting plate 60, the pump 85 It is provided.

The heat storage tank 80 is formed in a cylindrical shape and filled with water therein. Of course, other heat exchange medium may be filled in addition to water. Although not shown, the outer surface of the heat storage tank 70 may be surrounded by a heat insulating material for insulation, and a cover may surround the heat insulating material.

The water stored in the heat storage tank 70 is heated by receiving heat from the first exchanger (67). The first heat exchanger 67 is installed below the heat storage tank 70 to exchange heat with water stored in the heat storage tank 70. The first heat exchanger 67 may be attached to a plurality of fins on the outer peripheral surface in order to increase the heat exchange efficiency.

The first heat exchanger 67 is connected to the circulation pipes 61 and 63 connected to the heat collecting plate 60, so that the first heat transfer medium that absorbs or releases solar heat through the heat collecting plate 60 is the circulation pipe 61 ( Through 63) to the first heat exchanger (67). In this case, the high temperature first heat transfer medium absorbing solar heat exchanges heat with water filled in the heat storage tank 70 while passing through the first heat exchanger 67. The low temperature first heat transfer medium is circulated to the heat collecting plate 60 through the circulation pipes 61 and 63. Water received from the first heat exchanger 67 is heated to convection to the upper side of the heat storage tank (70). The heated water exchanges heat with seawater flowing inside the second heat exchanger 87 through the second heat exchanger 87 installed on the heat storage tank 70.

In the circulation pipes 61 and 63 connecting the heat collecting plate 60 and the first heat exchanger 67, valves 62 and 64 for opening and closing the flow path are provided at the inlet side and the outlet side of the first heat exchanger 50. Can be installed on each. Although not shown, a heat medium expansion tank connected to the circulation pipes 61 and 63 may be installed to prepare for expansion of the first heat transfer medium.

The inlet side of the second heat exchanger 87 is connected to the seawater collection pipe 81 extending from the seawater tank 80. And the outlet side is connected to the sea water inlet pipe (15). The seawater intake pipe 81 is provided with a pump 85 for transporting seawater and a valve 83 for opening and closing the flow path.

As described above, the solar heat transmitted from the heat collecting plate 60 to the first heat transfer medium is transferred to the water filled in the side tank 70, and the heat transferred to the water is transferred to the seawater through the second heat exchanger 87.

In the present invention, it is preferable that the expansion tank 73 is provided to correspond to the expansion of the water filled in the heat storage tank 70 by heating. The expansion tank 73 installed on the upper portion of the heat storage tank 70 has a supplementary water supply pipe 75 extending from the outside and into which water is introduced, connected to the upper portion, and the supplementary water supply pipe 75 according to the water level inside the expansion tank 73. Of the water stored in the heat storage tank 70 by interconnecting a buckle (not shown) for operating a valve (not shown) installed at an end of the heat storage tank 70 and the inside of the expansion tank 73. It may be provided with a connection pipe (not shown) to move the water according to expansion and contraction.

Therefore, when the water filled in the heat storage tank 70 is heated or boiled, the volume is expanded while expanding. In this case, a part of the water filled in the heat storage tank 70 is introduced into the expansion tank 73 through the connection pipe. The expansion tank 73 has a space that can accommodate the expanded water when inflated so that the water level is maintained only up to a certain height in normal. When the water is cooled and contracted or lacks of water, water is replenished from the expansion tank 73 to the inside of the heat storage tank 70 through the connection pipe. In this case, when the water level of the expansion tank 73 is lowered, the mouth is lowered and the valve provided at the end of the supplementary water supply pipe 75 opens the flow path of the supplemental water supply pipe 75 so that water is replenished. When the water rises to a certain level, the float floats and the valve closes the supplementary water supply pipe 75 so that the water supply is stopped.

And unlike the above-described heating means as another example of the present invention as a heating means seawater collection pipe 81 and seawater inlet pipe 15 is connected to each of the heat collecting plate 60 is connected to the seawater tank 80 The seawater supplied from the heat absorbing solar heat from the heat collecting plate 60 may be introduced into the evaporator through the seawater inlet pipe 15 immediately after being heated.

Meanwhile, in the present invention, the boiler 90, the third heat exchanger 97, and the temperature sensor (not shown) as auxiliary heating means for transferring heat to the seawater in case of lack of solar heat source, such as when the weather is cloudy or at night. C) and a controller (not shown).

Boiler 90 is a boiler that works by using gas, oil, briquettes, wood fire, etc. as a heat source. The third heat exchanger 97 is installed inside the heat storage tank 70 between the first and second heat exchangers 67 and 87. The third heat exchanger 97 is connected to the boiler 90 and the pipe 95 so that the water heated in the boiler 90 circulates and exchanges heat with the water stored in the heat storage tank 70.

And the inner upper side of the heat storage tank 70 is installed a conventional water temperature sensor for detecting the temperature of the water stored in the heat storage tank 70 is to output the detected temperature to the controller. The controller operates the boiler 90 when the temperature sensed by the temperature sensor is below the set temperature. When the boiler 90 is heated, heat is released through the third heat exchanger 97 to heat the temperature of the water stored in the heat storage tank 70 to a predetermined temperature. In the present invention, the seawater flowing into the evaporator through the seawater inlet pipe is preferably 50 to 60 ℃.

Therefore, in the present invention, unlike the conventional multi-stage flash evaporation method of superheating the seawater flowing into the evaporator at about 90 to 110 ° C, since the heating temperature of the seawater is low, the seawater scale adheres to the inside of the body where the seawater flows, so that the closing phenomenon of the pipe is almost eliminated. Does not occur. However, when the heating temperature is set higher, a conventional medicine may be added or a pretreatment process may be additionally performed to prevent the closing phenomenon.

When solar heat is not available as described above or solar heat is insufficient, the present invention is useful in constructing a stable desalination system because the boiler 90 heats seawater using an auxiliary heat source.

As described above, the present invention has been described with reference to one embodiment shown in the drawings, which is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. .

Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

1 is a schematic view showing a low energy desalination apparatus using solar heat according to an embodiment of the present invention,

Figure 2 is a perspective view showing a state in which the evaporator applied to the desalination apparatus of Figure 1 connected in multiple stages,

3 is a partially cutaway perspective view showing the inside of an evaporator applied to the desalination apparatus of FIG. 1.

<Description of the symbols for the main parts of the drawings>

20: evaporation unit 30: first evaporator

31: main body 35: roof

37: freshwater collection pipe 60: heat collecting plate

70: heat storage tank 80: seawater tank

90: boiler

Claims (3)

delete In the desalination apparatus which removes salt by naturally evaporating sea water by solar heat, A seawater flow path through which seawater flows from the seawater inlet pipe is formed, and a top of which is open so that the seawater flow path is exposed upward, and a roof of a light-transmitting material formed to be inclined on the top of the main body to cover the seawater flow path; An evaporation unit including at least one evaporator having a fresh water collection pipe installed inside the main body so that the seawater flowing through the seawater flow path is collected by the solar heat and is condensed from the roof; And heating means for heating the seawater flowing into the seawater inlet pipe using natural energy. The heating means includes a first heat exchanger for storing water therein, a first heat exchanger installed at an inner lower portion of the heat storage tank, and discharging heat to the water while circulating a first heat exchange medium absorbing solar heat from a solar heat collecting plate, and the heat storage A second heat exchanger installed at an inner upper portion of the tank and connected to a seawater intake pipe extending from a seawater storage tank, and the other end connected to the seawater inflow pipe, and absorbing heat from the water while seawater flows inside the seawater intake pipe; Low energy desalination apparatus using solar heat, characterized in that provided with a pump for transporting sea water. According to claim 2, wherein the heating means is a boiler, a third heat exchanger circulated in the water heated in the boiler and is installed between the first and second heat exchanger to discharge heat to the water, the interior of the heat storage tank And a temperature sensor installed at the controller and a controller for operating the boiler when the temperature detected by the temperature sensor is lower than or equal to a set temperature. The evaporation unit is formed by the evaporator is supported on the frame is arranged in a plurality of stages, The frame may include a rectangular base frame supported on the ground, a first horizontal frame spaced apart from the base frame, and a second horizontal frame spaced apart from the first horizontal frame. A vertical frame formed vertically at both left and right edges of the base frame to fix the first and second horizontal frames; The evaporation unit is a low-energy desalination device using solar heat, characterized in that further comprising a connection pipe interconnecting the evaporator installed in the base frame and the first and second horizontal frame, respectively.

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