JPS5811084A - Desalting device for sea water - Google Patents

Abstract

PURPOSE:To make the reduction in water making costs possible by constituting a heating section of a regenerating section for absorbing liquid having a concentrator and a condenser contg. heat exchangers, and a diluting section for absorbing liquid having an evaporator and an absorber contg. heat exchangers. CONSTITUTION:Since a regenerating section 10 for absorbing liquid is held under the satd. pressure of heated absorbing liquid, the water of the absorbing liquid evaporates and steam migrates from a concentrator 11 to a condenser 12. Sea water 7 is kept flowed in the tubes of a heat exchanger 14 in the condenser 12, and the sea water 7 in the tubes is heated by receiving the heat of condensation of the steam in the tubes. The heated sea water is supplied to a sea water desalting device. Since a diluting section 20 for absorbing liquid is maintained at the satd. vapor pressure of the heated water, steam is generated and is absorbed in the absorbing liquid flowing from an evaporator 201 down into an absorber 22. Therefore, the absorbing liquid is heated by absorbing the enthalpy component that the condensed steam possesses and the sea water 7 in the heat transmitting tubes of a heat exchanger 24 is heated by such heated liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seawater desalination apparatus, particularly a multistage flash evaporation type seawater desalination apparatus.

Fig. 1 is a system diagram of a conventional multi-stage flash evaporation type seawater desalination equipment, in which 1 is a brine heater, 2 is a heat recovery section evaporation stage, 3 is a heat release section evaporation stage, 4 is a seawater pretreatment device, and 5 indicates a pump, and usually heating steam is supplied from a steam generator (hereinafter referred to as a boiler) to a 6-keb line heater,
Seawater 7 is heated by the latent heat of this steam 6. At this time, the seawater temperature at the outlet of the brine heater is generally 100
It is being driven around C.

In particular, multi-stage flash evaporative seawater desalination equipment is suitable for large-scale seawater desalination, but because it uses high-quality steam as a heating source for seawater, the cost of fresh water is rising year by year, and the energy Countries that rely on imported water sources tend to be reluctant to install multi-stage flash evaporation desalination systems, and as a result, they are still not at a stage where they can be useful in resolving water shortages during dry periods.

On the other hand, the recent energy crisis has promoted energy conservation in all areas, and seawater desalination is no exception. There are many problems that need to be solved in order to put them into practical use, such as the large heat transfer area for the heat exchange or the large amount of power required for extraction.

The present invention eliminates these problems and makes it possible to provide a seawater desalination device that can effectively use normal waste heat in the form of hot water (hereinafter referred to as drain) down to low temperatures and can reduce the cost of water production. In a multi-stage flattened evaporation type seawater desalination equipment that has a heating section, an evaporation section, and a condensation section as its main groove components, the heating section is replaced by a condenser with a built-in heat exchanger and a condenser, respectively. The first feature is that the absorption type heat exchanger is composed of an absorption liquid regeneration section having a heat exchanger and an absorption liquid dilution section having an evaporator and an absorber, each having a built-in heat exchanger. An absorbent liquid that has an absorbent regeneration unit, an evaporator and an absorber each with a built-in heat exchanger, which is similar to a concentrator with a built-in exchanger and a direct contact condenser that distributes and flows down the circulating seawater through a seawater desalination device. The second feature is that it is constituted by an absorption heat exchanger that is similar to the dilution section.

In other words, if we consider the case where a drain is used as the heat source in the conventional multi-stage flash evaporation seawater desalination equipment shown in Figure 1, the brine heater causes a drop in the negative heat flow rate due to liquid-liquid heat transfer. OE is the heat transfer surface of the brine heater.
), and either the minimum operating temperature of the drain is limited to 100C or higher, or the maximum temperature needs to be lowered. In this way, conventional multi-stage flash evaporation seawater desalination equipment can effectively dissipate water when driven by heating steam from a boiler as a heat source, but there are many problems when using exhaust heat sources such as drains. It became clear that The present invention solves the problem of using condensate as a heat source in a multi-stage flash evaporation type seawater desalination equipment by using an absorption type heat exchanger in the heating section. This made it possible to achieve the objectives of

Examples will be described below.

FIG. 2 is a system diagram of an embodiment, showing the basic configuration of the present invention. In this figure, the same parts as in Figure 1 are given the same symbols, and the difference from Figure 1 is that an absorption heat exchanger is installed in the heating section instead of a brine heater. be.

This absorption heat exchanger consists of an absorption liquid regeneration section 10 and an absorption liquid dilution section 20.
, the condenser 12, the absorption liquid dilution section 20 is connected to the evaporator 21. It consists of an absorber 22, and heat exchangers 13, 14, 23゜24 are built into each vessel, and the drain 8 is flowed into the pipes of the heat exchangers 13 and 23 to remove the absorbed liquid outside the pipes. heat up.

At this time, since the absorption liquid regeneration unit 10 is maintained at the saturation pressure of the heated absorption liquid, the moisture in the absorption liquid evaporates and steam moves from the condenser 11 to the condenser 12. Seawater 7 is flowing inside the tubes of the heat exchanger 14 in the condenser 12, and the seawater 7 inside the tubes is heated by the heat of condensation of the steam outside the tubes, and is supplied to the seawater desalination apparatus.

On the other hand, the absorbed liquid is transferred to the absorber 22 and flows down outside the tube of the heat exchanger 24. At this time, the inside of the tube of the heat exchanger 23 of the evaporator 21 is used in the heat exchanger 13 and once The condensate that has dropped is reintroduced and heats the water outside the tube. At this time, since the absorption liquid diluting section 20 is maintained at the saturated vapor pressure of the heated water, water vapor is generated and flows from the evaporator 21 to the absorber 2.
2, and is absorbed by the absorption liquid flowing from above. Therefore, the absorption liquid absorbs the enthalpy of the condensed vapor and increases its temperature. The seawater 7 flowing through the heat exchanger tubes of the heat exchanger 24 is heated by this heated liquid and is supplied to the seawater desalination apparatus.

A specific example of a multi-stage flash evaporation seawater desalination apparatus using an absorption heat exchanger operating in this manner as a heating section will be described. Of the various types of food waste at thermal power plants, etc.
For example, the operating temperature when using a 194C drain 1]
In the I situation, the temperature is up to 145C in the heat exchanger 13, and 145C to 75C in the heat exchanger 23. At this time, the temperature of the seawater supplied to the seawater desalination equipment is always 9
50 constant, and can supply seawater at a temperature higher than the drain discharge temperature. Therefore, effective use of hot water can be achieved.

In addition, when an absorption liquid storage tank 30 is provided between the concentrator 13 and the absorber 22, as in the case of the example shown in FIG.
Even when the storage tank 30 causes a decrease in the performance of the sydren, or even when the flow rate changes, the amount of seawater heating in the absorption liquid regeneration unit 10 is reduced and the seawater is heated in the absorption liquid dilution unit 20. , it is possible to perform stable operation by keeping the amount of heat input to the seawater desalination equipment constant.

Figure 3 is a system diagram of another embodiment, in which the same parts as in Figure 2 are given the same reference numerals. An ordinary multi-tubular heat exchanger (hereinafter referred to as an intermediate heater) 40 is installed between the liquid diluting section 20 and the liquid diluting section 20. In this embodiment, the temperature of the drain used in the absorption liquid regeneration unit 10 and the absorption liquid dilution unit 20 can be optimized. That is, in the specific example shown in the explanation of the above-mentioned embodiment, the operating temperature of the condensate in the absorption liquid regeneration section is 194C to 145C1, while the same flow rate of condensate can be processed by setting it to 99C to 75C in the absorption liquid dilution section. , in this case 145C~
Although up to 75 CIl was not necessary, in this example, since the intermediate heater 40 is installed in this part, this temperature can be used to heat the seawater. In other words, it is possible to heat seawater to a temperature that was not necessary in the specific example shown in the explanation of the above-mentioned embodiment, and the effective use of drain can be further promoted, and the amount of fresh water produced per hot water needle is increased. can.

FIG. 4 is a systematic diagram of an embodiment of the music, in which the same parts as in FIGS. 2 and 3 are given the same reference numerals. This embodiment differs from the embodiment of FIG.
In addition, since a direct contact condenser 15 using seawater is used, the seawater circulating in the seawater desalination equipment is dispersed and flowed down from the dispersion nozzle 16 and directly interacts with the steam moving from the first and second vessels 11. It is heated upon contact and supplied to the seawater desalination equipment. (9) To replenish water to the evaporator 21, a part of the blowdown seawater 9 of the seawater desalination apparatus is used. Since the blowdown seawater 9 in the seawater desalination apparatus is almost completely deaerated, it is suitable as makeup water to the evaporator 21. Note that the make-up water to the evaporator 21 may be other than blown-down seawater as long as it is deaerated in a vacuum.

In this embodiment, the heat exchanger 14, which has the largest heat transfer area in the embodiment of FIG. 3, can be omitted, so that the device cost can be further reduced.

FIG. 5 is a system diagram of the main parts of still another embodiment, in which the same parts as in FIG. The intermediate heater 40 of the embodiment shown in FIG.
1, and a nozzle 42 is provided for injecting a portion of the seawater from the seawater desalination apparatus into the heat transfer tube of the intermediate heater 41. In this embodiment, the absorbent regenerating section 10 and the absorbent diluting section 2o are connected without a storage tank.

(10) In this example, the shell of the intermediate heater can be omitted, and a portion of the seawater is injected into the heat transfer tube, which promotes agitation of the flow flowing down the tube surface and increases the heat transfer rate. It is now possible to improve the heat transfer area, which has the effect of reducing the heat transfer area.

As described above, the seawater desalination apparatus of the embodiment has the following advantages: (1) The drain can be effectively used down to low temperatures;
The amount of water produced per unit will increase compared to the case with conventional equipment.

(2) Since the heat transfer area, which accounts for most of the device cost, can be reduced, it is possible to provide an inexpensive device.

(3) By providing an absorption liquid storage tank, changes in the temperature and flow rate of the drain can be absorbed, and stable operating conditions for the seawater freshwater apparatus can be obtained.

As described above, the seawater desalination apparatus of the present invention can effectively use normal waste heat in the form of hot water down to low temperatures, and can reduce the cost of water production, making it an industrially effective device. It is.

[Brief explanation of the drawing]

(11) FIG. 1 is a system diagram of a conventional seawater desalination device, FIGS. 2, 3, and 4 are system diagrams of different embodiments of the seawater desalination device of the present invention, and FIG. 5 is a system diagram of a conventional seawater desalination device. is a system diagram of the main parts of the same embodiment. 7... Seawater, 8... Drain, 9... Blowdown seawater, 10... Absorbent regeneration section, 11... Concentrator, 1
2... Condenser, 13.14... Heat exchanger, 15...
・Direct contact condenser, 20... Absorption liquid dilution section, 21.
...Evaporator, 22...Absorber, 23.24...Heat exchanger, 30...Storage tank, 40.41...Multiple tube heat exchanger. Agent Patent attorney Hiroo Nagasaki (and 1 other person) (12) \0 1 \\”1 ■

Claims (1)

[Claims] 1. A multi-stage flash evaporation type -N water desalination apparatus having 141 main parts including a heating part, an evaporation part and a condensation part, each of which has a built-in heat exchanger. Seawater characterized by being constituted by an absorption type heat exchanger consisting of an absorption liquid internal part having an enigma condenser and a condenser, and an absorption liquid dilution part having an evaporator and an absorber each having a built-in heat exchanger. Desalination equipment. 2. The seawater desalination apparatus according to claim 1, wherein a shell-and-tube heat exchanger is provided between the absorption liquid regeneration section and the absorption liquid dilution section. 3. The method according to claim 1 or 2, wherein a storage tank for condensate from the absorbent regenerating section is provided between the absorbent regenerating section and the absorbent diluting section. Seawater desalination equipment. 4. In a multi-stage flash evaporation type seawater desalination device whose main constituent parts are a heating section, an evaporation section and a condensation section,
The heating section is divided into an absorption liquid regeneration section consisting of a concentrator with a built-in heat exchanger and a direct contact condenser that distributes and flows down the seawater circulating through the seawater desalination device, and an evaporator and absorber each with a built-in heat exchanger. 1. A seawater desalination apparatus comprising an absorption heat exchanger comprising an absorption liquid diluting section having the following features: 5. The river water desalination apparatus according to claim 4, wherein a multi-tubular heat exchanger is provided between the absorbent liquid phase, raw part and the absorbent diluted part. 6. The multi-tubular heat exchanger is provided in the direct contact condenser and has a nozzle for injecting a part of the seawater circulating through the seawater desalination device into the heat transfer tubes. The seawater desalination device according to scope item 5. 7゜A storage tank for the concentrated liquid from the absorption liquid regeneration unit is provided between the absorption liquid regeneration unit and the absorption liquid dilution unit, claim 4 or claim 5 or 6. The sewage drinking water system described above.