CN102815757B - Seawater desalination apparatus - Google Patents

Abstract

The invention relates to a seawater desalination device, comprising an air humidification tower and an air dehumidification tower, the upper parts of the air humidification tower and the air dehumidification tower communicate with each other; The air blowing device, the water inlet, the water distribution pipe connected with the water inlet and the seawater discharge outlet for the seawater in the air humidification tower are discharged, and the two ends of the heating tube are respectively provided with heat source inlets for inputting the exhaust steam of the thermal power plant And the heat source outlet for outputting exhausted steam; the air dehumidification tower is equipped with cooling tubes and fresh water outlets, and the two ends of the cooling tubes are respectively equipped with water inlets and water outlets. The above seawater desalination device can effectively use the waste heat of the thermal power plant to produce fresh water, so that the cost of seawater desalination is greatly reduced.

Description

Seawater desalination device

technical field

The invention belongs to the technical field of water treatment, in particular to a seawater desalination device.

Background technique

Due to the lack of fresh water resources, seawater desalination technology has received extensive attention. Since salt water becomes fresh water, it is an entropy reduction process, which cannot be carried out spontaneously. Existing seawater desalination methods such as distillation, reverse osmosis, electrodialysis, etc., all need to consume a lot of energy, which makes seawater desalination economical. The cost is too high, which is not conducive to wide application.

As shown in Figure 1, it is the working principle diagram of the existing thermal power plant. When the thermal power plant generates electricity, according to the second law of thermodynamics, only part of the heat generated by the combustion of fuel in the boiler is converted into electricity, and the exhausted steam is condensed When burning, the heat released accounts for more than 50% of the heat of combustion and discharge, which is a huge waste heat. At present, the evaporation capacity of the boiler matched with the 600MW generating set is 2008t/h. Generally, the latent heat of vaporization released when each kilogram of steam is condensed in the steamer is 2383-2424kj/kg, so the heat released by the condenser when condensed is about 1.145* 109kcal/h (1cal=4.1840J), it can raise the temperature of about 110,000 tons of cooling water by 10°C per hour. This huge heat source can raise the temperature of cooling water discharged from thermal power plants by at least 8°C. Therefore, if the waste heat of the thermal power plant can be used for seawater desalination and the waste heat can be effectively utilized, the cost of desalination can be greatly reduced.

Contents of the invention

The technical problem to be solved by the present invention is to provide a device for desalination of seawater by using the waste heat of exhausted steam in a power plant.

The present invention is achieved by providing a seawater desalination device, including an air humidification tower and an air dehumidification tower, and the upper parts of the air humidification tower and the air dehumidification tower communicate with each other; the air humidification tower includes a heating column pipe, a blower device that provides air to the air humidification tower, a water inlet, a water distribution pipe communicated with the water inlet, and a seawater discharge outlet for the seawater in the air humidification tower to discharge, and the two heating tubes The heat source inlet for inputting the exhausted steam of the thermal power plant and the heat source outlet for outputting the exhausted steam are respectively provided at the ends; cooling tubes and fresh water outlets are arranged in the air dehumidification tower, and the two ends of the cooling tubes are respectively set There is a water inlet and a water outlet; the outlet of the heat source is connected with a steam-water separation device, and the steam-water separation device is connected with the condenser of the power plant; the lower part of the air dehumidification tower is also provided with an exhaust hole; the The exhaust hole on the air dehumidification tower is connected with the air inlet of the blowing device; the water inlet is input with deep sea water, and the water outlet is connected with the water inlet on the air humidification tower, or discharged .

Further, the water inlet and the seawater outlet in the air humidification tower are respectively located at the upper part and the lower part of the air humidification tower.

Further, the air humidification tower further includes a spray head installed on the water distribution pipe, and the water distribution pipe is located at an upper part inside the air humidification tower.

Further, the heating tube of the air humidification tower includes a conduit and heating fins installed on the conduit.

Further, the heat source inlet and the heat source outlet are respectively located at the upper part and the lower part of the air humidification tower; the heat source inlet is input into the exhaust steam of the thermal power plant.

Further, the cooling tubes of the air dehumidification tower include conduits and cooling fins installed on the conduits.

Further, the water inlet and the water outlet are respectively located at the lower part and the upper part of the air dehumidification tower.

Further, the fresh water outlet is located at the lower part or bottom of the air dehumidification tower.

Further, the surface of the air humidification tower and the surface of the air dehumidification tower are both provided with insulation layers.

Compared with the prior art, the seawater desalination device of the present invention can effectively utilize the waste heat of a thermal power plant to produce fresh water, thereby greatly reducing the cost of seawater desalination.

Description of drawings

Fig. 1 is the working principle diagram of existing thermal power plant;

Fig. 2 is a working principle diagram of a preferred embodiment of the present invention;

Fig. 3 is a structural principle diagram of a preferred embodiment of the present invention.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The present invention is transformed on the basis of the existing thermal power plant, as shown in Figure 2, which is the working principle diagram of the present invention, under the premise of not affecting the normal operation of the thermal power plant, the waste steam discharged from the steam turbine is separated One is used for seawater desalination of the seawater desalination device of the present invention. In Fig. 2, the left part is the equipment and working principle of the existing thermal power plant, and the humidifying tower and the dehumidifying tower part are the seawater desalination device of the present invention.

Specifically, as shown in Figure 2 and Figure 3, it is a preferred embodiment of the present invention, the seawater desalination device includes an air humidification tower 100 and an air dehumidification tower 200, and the air humidification tower 100 and the air dehumidification tower 200 The upper part is connected with each other.

The air humidification tower 100 includes a water inlet 101 , a water distribution pipe 102 , a spray head 103 , an air blast device 104 , a seawater outlet 105 and a heating tube 106 . The water distribution pipe 102 and the nozzle 103 are located at the upper part inside the air humidification tower 100, and communicate with the water inlet 101. In this embodiment, the seawater input into the water inlet 101 can be sea surface seawater or the cooling tube of the air dehumidification tower. Cooled seawater discharged from the nozzle. The air blowing device 104 is located at the lower portion of the air humidification tower 100 , and the seawater outlet 105 is provided at the bottom or lower portion of the air humidification tower 100 . The heating tube 106 is located inside the air humidification tower 100. The heating tube 106 includes a conduit and heat dissipation fins (not shown in the figure) installed on the conduit. The upper end of the heating tube 106 is provided with a heat source inlet 1061, and the lower end is provided with a heat source. Outlet 1062, the heat source of the heating tube 106 is the exhausted steam from the steam turbine of the power plant, and the exhausted steam flows through the heating tube 106 from top to bottom, so that the temperature of the seawater and air outside the heating tube 106 rises, and the seawater evaporates. The humidity of the air increases, forming saturated hot and humid air with a higher temperature (for example, about 70°C). In addition, an insulation layer 107 is provided on the surface of the air humidification tower 100 to prevent the temperature inside the air humidification tower from dropping.

The inside of the air dehumidification tower 200 is provided with cooling tubes 201 and a fresh water outlet 202 . The cooling tube 201 includes a conduit and cooling fins (not shown in the figure) installed on the conduit. The cooling tube 201 is provided with a water inlet 2011 below and a water outlet 2012 above. In this embodiment, the cooling in the cooling tube The medium can be sea surface seawater or deep cold seawater (preferably deep cold seawater, because of its low temperature, large temperature difference, and high freshwater yield), and deep cold seawater can be obtained by means of pumps or other existing technologies obtain. Seawater enters from the water inlet 2011 and flows through the cooling tubes 201 from bottom to top, so that the saturated hot and humid air from the air humidification tower outside the cooling tubes is cooled, and the water vapor in the saturated hot and humid air is condensed into dew and collected into fresh water , discharged from the fresh water outlet. The fresh water outlet 202 is located at the lower part or the bottom of the air dehumidification tower 200 . The surface of the air dehumidification tower 200 is provided with an insulation layer 203 for preventing the temperature inside the air dehumidification tower from rising. In addition, an exhaust hole 204 is provided below the air dehumidification tower 200 .

When the above-mentioned seawater desalination device prepares fresh water, seawater enters the water distribution pipe 102 in the air humidification tower 100 from the water inlet 101, is sprayed in the air humidification tower 100 by the nozzle 103, and contacts with the air blown in by the blower device 104, The air humidity in the air humidification tower 100 is increased to reach saturation, and the seawater is evaporated through the heating of the heating tubes to form saturated hot and humid air at a higher temperature. The saturated hot and humid air in the tower is driven by the blower device 104 Next, from the air humidification tower 100 into the air dehumidification tower 200, the saturated hot humid air is cooled by the cooling tube 201 in the air dehumidification tower 200, and then turns into dew, which is collected into fresh water and flows out from the fresh water outlet 202.

The unevaporated seawater in the humidification tower 100 is discharged from the seawater discharge port 105 .

In order to better realize resource recycling, the above-mentioned heat source outlet 1062 can be connected with a steam-water separation device 300, and the steam-water separation device 300 is also connected with the condenser of the power plant. In this way, after the exhaust steam discharged from the heat source outlet 1062 of the heating tube 106 passes through the steam-water separation device for steam-water separation, air and condensed water are obtained, and the obtained air can be circulated to the condenser of the thermal power plant, and the obtained condensed water can be recovered. Reuse.

In addition, the exhaust hole 204 on the dehumidification tower 200 can communicate with the air inlet of the air blowing device 104 . In this way, the air in the air dehumidification tower 200 can be circulated to the air inlet of the air blowing device 104 after being exhausted from the exhaust hole 204 , so as to be circulated and blown into the humidification tower 100 . The water outlet 2012 on the dehumidification tower 200 can communicate with the water inlet 101 on the humidification tower 100 . In this way, the seawater discharged from the water outlet 2012 of the cooling tube 201 can enter the water inlet 101 of the air humidification tower 100 for reuse, which is conducive to improving the temperature of seawater entering the air humidification tower, increasing the temperature of saturated hot and humid air, and improving Freshwater production.

Next, according to the above-mentioned seawater desalination device, a few practical application examples are given to illustrate. The absolute humidity and enthalpy of the air under the conditions of multiple temperatures and relative humidity listed in the table below are all from the [air humidity enthalpy diagram] :

Example 1: Route A→B1. Assume that the sea surface air temperature is 30°C and the relative air humidity is 60%. At this time, the state point is at point A in Table 1, the absolute humidity is 16 grams/KG dry air, and the enthalpy is 71KJ/KG dry air. At this time, if the air is cooled to point B1 with deep sea water, that is, assuming that it is cooled to 15°C, (absolute humidity is 10.5 grams/KG dry air), 16-10.5=5.5 grams of dew will be produced, i.e. fresh water. That is to say, by utilizing the cold source of deep seawater, fresh water can be obtained without consuming energy (except for lifting, transporting seawater, and air energy).

Example 2: Route A→B2→B1. Assume that the air is humidified and saturated with 30°C seawater. But heat, the state will move along the isenthalpy line to the intersection point B2 of the saturation line (relative humidity 100% line), and the temperature will drop to 24°C (absolute humidity is 18.5 grams/KG dry air). At this time, if it is cooled to point B1 with deep sea water, that is, assuming that it is cooled to 15° C., 18.5-10.5=8 grams of fresh water will be produced. That is to say, by utilizing the cold source of deep seawater and adding humidified air process, without consuming energy, more fresh water than the above example 1 can be obtained.

Example 3: Route A→B3→B2→B1. It is also assumed that 30°C seawater is used to humidify the air to saturate the air; at the same time, seawater has relatively large heat, so that the air basically does not cool down, forming saturated air at 30°C, that is, reaching point B3 in Table 1 (absolute humidity is 27 g/KG dry air). It is cooled again, cross B2 to B1, will obtain 27-10.5=16.5 gram of fresh water, increase than the output of above-mentioned example 2. That is to say, more fresh water than above-mentioned example 2 can be obtained by heating the humidified air with sea water as a heat source.

Example 4: Route A→B4→B3→B2→B1. The above three routes are not the case of the heating source. Now assume that there are other heat sources, such as exhaust steam in power plants, solar energy or other heat sources, so that the air temperature increases at the same time. At this time, assume that the air temperature reaches 35 ° C, that is, the surface Point B4 in 1 (absolute humidity 36 grams/KG dry air). If at this moment, cool with 30 ℃ of seawater, assume that it is cooled to 30 ℃, B3 point, obtain fresh water 36-27=9 grams. But, if be to cool it with deep seawater, cross B3 point, B2 point to B1 point, will produce fresh water 36-10.5=25.2 grams, be 2.8 times of 9 grams.

To sum up, the seawater desalination device of the present invention can effectively utilize the waste heat of a thermal power plant to produce fresh water, thereby greatly reducing the cost of seawater desalination.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (9)

1. a sea water desalinating plant, comprises air humidification tower and air dehumidification tower, it is characterized in that, the top of described air humidification tower and air dehumidification tower is interconnected; Described air humidification tower comprises heating tubulation, provides air-blast device, water-in, the water distributor being communicated with described water-in of air and the seawater relief outlet of discharging for the seawater in described air humidification tower to air humidification tower, and the two ends of described heating tubulation are respectively equipped with the thermal source entrance of the weary steam of input thermal power plant and export the thermal source outlet of described weary steam; In described air dehumidification tower, be provided with cooling tubulation and fresh water relief outlet, the two ends of described cooling tubulation are respectively equipped with water inlet and water outlet; Described thermal source outlet is connected with a water separator, and described water separator is connected with the condenser in power station; The lower portion of described air dehumidification tower is also provided with venting hole; Venting hole on described air dehumidification tower is connected with the inlet mouth of described air-blast device; Described water inlet input depths seawater, described water outlet is connected with the water-in on air humidification tower, or discharge.

2. sea water desalinating plant as claimed in claim 1, is characterized in that, the water-in in described air humidification tower and seawater relief outlet lay respectively at position, top and the lower portion of described air humidification tower.

3. sea water desalinating plant as claimed in claim 1, is characterized in that, described air humidification tower also comprises the shower nozzle being arranged on described water distributor, and described water distributor is positioned at the position, top of described air humidification tower inside.

4. sea water desalinating plant as claimed in claim 1, is characterized in that, the heating tubulation of described air humidification tower comprises conduit and is arranged on described supravasal heating fin.

5. sea water desalinating plant as claimed in claim 1, is characterized in that, described thermal source entrance and thermal source outlet lay respectively at position, top and the lower portion of described air humidification tower; The weary steam of described thermal source entrance input thermal power plant.

6. sea water desalinating plant as claimed in claim 1, is characterized in that, the cooling tubulation of described air dehumidification tower comprises conduit and is arranged on described supravasal radiating fin.

7. sea water desalinating plant as claimed in claim 1, is characterized in that, described water inlet and water outlet lay respectively at lower portion and the position, top of described air dehumidification tower.

8. sea water desalinating plant as claimed in claim 1, is characterized in that, described fresh water relief outlet is positioned at lower portion or the bottom of described air dehumidification tower.

9. sea water desalinating plant as claimed in claim 1, is characterized in that, described air humidification tower surface and air dehumidification tower surface are equipped with thermal insulation layer.