JPH0389901A - Multistage flash evaporator - Google Patents

Abstract

PURPOSE:To increase fresh water production capacities by providing a flow means for a pervaporation membrane module installed in a brine retention section of a vaporization chamber to feed the vapor having passed through said membrane to the vicinity of a subsequent condenser to be condensed. CONSTITUTION:Vaporization chambers 4, wherein heated brine is vaporized while the generated vapor condenses at a condenser 13 to obtain fresh water, are arranged in multistage relationship so that heated brine is passed therethrough. A pervaporation membrane module 26 is provided in each brine retention section 8 of the vaporization chamber 4, whereby a flow means 27 is provided for the module 26 to feed the vapor having passed through the pervaporation membrane to the vicinity of the subsequent condenser 13 to be condensed thereby. As a result, fresh water production capacity can be increased.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a multi-stage flash evaporator that evaporates heated brine and condenses it to obtain fresh water, and in particular makes it possible to increase the amount of water used. This invention relates to a multi-stage flash evaporator.

[Prior Art] Multi-stage flash evaporation devices are generally known as devices for obtaining fresh water from seawater (brine).

This multi-stage flash evaporator, as shown in Figure 2,
The brine in the brine reservoir C in the evaporation chamber downstream of the ripening rejection section a is transferred to
Brine is made to flow sequentially from the condenser f to the condenser f and the brine heater g in the previous stage, and is heated by the brine heater g. This heated brine is passed sequentially from the evaporation chamber in the front stage of the heat recovery section e to the evaporation chamber in the rear stage of the heat rejection section a, and the vapor evaporated from the brine reservoir C in each evaporation chamber passes through the gas-liquid separator. The condensed WJ liquid, that is, fresh water, which is condensed in a condenser f, is received by a saucer i, and the fresh water is taken out by an extraction bomb j.

[Problems to be solved by the invention] By the way, in the conventional multi-stage flash evaporator,
To increase the amount of water supplied, increase the flow rate of the circulating brine that flows into the evaporation chamber before the heat recovery section and/or raise the temperature of the heated brine or lower the temperature of the brine that flows into the evaporation chamber before the ripening and rejection section. However, there is a limit to how much the brine can be heated with the brine heater, and the area of the brine reservoir in the evaporation chamber would need to be increased, so no further increase in the amount of water could be expected.

Therefore, the present invention was made to solve the above problems, and an object of the present invention is to provide a multi-stage flash evaporation device that makes it possible to increase the amount of water supplied.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention evaporates heated brine and condenses it in a condenser to obtain fresh water through an evaporation chamber in which heated brine flows in multiple stages. In the formed multi-stage flash evaporator, a pervaporation membrane module is provided in the brine thin wall of the evaporation chamber, and the vapor that has permeated through the pervaporation membrane is supplied to the pervaporation membrane module near the condenser in the subsequent stage for condensation. It provides a means of distribution.

[Function] According to ``23 Jizu Sei, because a pervaporation membrane module is installed (suspended) in the brine stream of each stage of evaporation chamber, the vapor that permeates through the pervaporation membrane is transferred through the flow means. Since fresh water is obtained by being supplied near the condenser in the latter stage and condensed, the amount of water supplied will be increased by 11 compared to the conventional amount of fresh water obtained from the steam of the pervaporation membrane module.

[Example] A preferred example of the present invention will be described based on the accompanying drawings.

In FIG. 1, J is a multistage flash evaporator for obtaining fresh water from seawater (brine), and is equipped with an evaporator 2.

The interior of the evaporator 2 is partitioned by partition walls 3 to form multistage evaporation chambers 4. These evaporation chambers 1 are communicated with each other via orifices 5 provided at the lower part of the partition wall 3.
During operation, heated brine flows from the evaporation chamber 4 in the first stage to the evaporation chamber 4 in the second stage F& through the group of orifices 5. In these evaporation chambers 4, a large number of evaporation chambers 4 between the front stages are constituted by a heat recovery section 6, and a small number of evaporation chambers 4 at a rear stage are constituted by a heat rejection section 7.

Each evaporation chamber 4 is formed with the same +1/l structure, and has a brine tank 8 at the bottom, and a gas-liquid separator at the top through which the vapor evaporated from the brine tank 8 passes and which receives the condensate dripping. A saucer 10 is provided, and the upper part is configured as a condensing part 11 and the lower part is configured as an evaporating part 12. A condenser 13 is provided above the saucer 10 of the condensing section 11, and
The drain of the saucer 10 communicates with an extraction pump 14 which extracts the condensate or fresh water.

A seawater supply pipe 15 for supplying seawater as cooling water is connected to the inlet of the condenser 13 at the last stage of the heat rejection section 7,
The seawater from the seawater supply pipe 15 is configured to sequentially flow from the last-stage condenser 13 of the heat rejection section 7 to the first-stage condenser 13. A discharge pipe 16 for discharging seawater is connected to the outlet of the compression vessel 13 at the frontmost stage of the heat rejection section 7. A reservoir piping 17 is connected to the brine stream 8.

Connected to the last stage of the heat rejection section 7 is one brine amount adjusting pipe G equipped with a brine 41F output pump 18 for adjusting the overall brine amount. Further, at least a part of the brine in the brine reservoir 8 at the last stage is the brine IJ6
The heat is sequentially distributed from the ring pump 20 and the condenser 13 at the last stage of the heat recovery section 6 to the condenser 13 at the front stage. The output [1] of the condenser 13 at the front stage of the heat recovery section 6 is connected to the brine heater [1] of the brine heater 21, and the brine output [1] at the front stage of the heat recovery section 6 is connected to the brine heater 21. brine circulation path 2.
2 is formed. The brine heater 21 is communicated with a heat supply channel 23 for supplying heated steam, and a drainage channel 25 equipped with a content sensor 1 to a pump 24 for discharging liquefied steam from the brine heater 21. It is communicated.

Further, in the brine reservoir 8 of each evaporation chamber 4 from the frontmost stage of the heat recovery section 6 to the last stage of the heat rejection section 7, a pervaporation membrane module 1-26 is provided, respectively. Although not shown, these pervaporation membrane modules 26 mainly consist of a pervaporation membrane that allows only vaporized vapor to pass therethrough and a permeation vapor chamber into which the vapor flows. 27 is connected to a flow passage 28 forming a 4'/mouth.

The outlet of the flow path 28 is the module 2 of the flow path 28.
A condenser 13 near the condenser 13 of the evaporation chamber 4 provided with six or more condensers 13 one stage downstream (relative to the flow of heated brine)
It is connected to a nearby condensing section 11, and the vapor that has passed through the pervaporation membrane is supplied to either condensing section 11 by means of two valves. The condensing section that communicates the outlet of the flow path may be the condensing section of the subsequent evaporation chamber as long as the temperature is lower than that of the thin-walled brine of the pervaporation membrane module in the flow path.

Next, the operation of this embodiment will be explained.

The seawater supplied to the condenser 13 of the ripening section 7 through the seawater supply pipe 15 is used to condense the steam that evaporated in the evaporation chamber 4 and passed through the gas-liquid separator 9, and a portion of the warmed seawater is is discharged H14 via the discharge pipe 16, and the remainder is supplied via the pipe 17 to the prine reservoir 8 at the last stage of the ripening rejection section 7, where it is mixed with the circulating brine. The amount of brine is regulated by a brine amount adjustment pipe 19 equipped with a brine discharge pump 18 of 6 Mi.

The mixed brine is sent to the brine circulation brine.

20, the water is sequentially distributed from the condenser 13 at the rear stage of the heat recovery section 6 to the condenser 13 at the front stage, the brine heater 2], and from the evaporation chamber 4 at the front stage of the heat recovery section 6 to the evaporation chamber 4 at the rear stage of the heat recovery section 7. is circulated.

At this time, the brine heated by the brine heater 21 undergoes flash evaporation while the temperature and pressure of the brine are sequentially lowered starting from the previous evaporation chamber 4. The vapor thus evaporated passes through the gas-liquid separator 9 and into the condenser 13.
The condensed liquid, that is, the fresh water that drips is received in the saucer 10 (the fresh water is taken out via the extraction pump 14). will be done.

In addition, since the pervaporation membrane module 26 is provided in the brine reservoir 8 of the evaporation chamber 4 of each stage, the temperature at the outlet of the flow path 28 of the module 26 is lower than that of the brine in the brine reservoir 8. , a temperature difference occurs between the brine on both sides of the pervaporation membrane and the pervaporation chamber, and due to a vapor pressure difference corresponding to this temperature difference, the vapor of the brine passes through the pervaporation membrane and flows into the pervaporation chamber. . The vapor that has flowed into the pervaporation chamber is supplied to the vicinity of the condenser 13 via the flow path 28 and is then vaporized in the condenser 13? a, and fresh water will be obtained.

7 Therefore, the multi-stage flash evaporation device 1 according to the present invention
In addition to the fresh water obtained by condensing the flash-evaporated vapor, fresh water can also be obtained from the vapor that has passed through the pervaporation membrane of the pervaporation membrane module 26. The amount of water supplied will increase by the amount of fresh water.

[Effects of the Invention] In summary, according to the present invention, a pervaporation membrane module is provided in the heated brine reservoir of the evaporation chamber of each stage, and the vapor that permeates through the pervaporation membrane is condensed in the t & stage through the flow means. Fresh water is supplied near the vessel and condensed to obtain fresh water, which has the excellent effect of increasing the amount of water used.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram not showing a conventional example. In the figure, 4 is an evaporation chamber, 8 is a brine reservoir, ], 3 G,,
1 is a condenser, 26 is a pervaporation membrane module, and 27 is a flow means.

Claims (1)

[Claims] 1. In a multi-stage flash evaporation device in which heated brine is evaporated and fresh water is obtained by condensing it in a condenser, the evaporation chamber is formed in multiple stages so that the heated brine flows, and a pervaporation membrane module is installed in the brine reservoir of the evaporation chamber. established,
A multi-stage flash evaporation device, characterized in that the pervaporation membrane module is provided with a flow means for supplying the vapor that has permeated through the pervaporation membrane to the vicinity of a subsequent condenser and condensing it.