JPH04358502A - Low boiling point separation method and device - Google Patents

Abstract

PURPOSE:To separate and recover a low boiling material such as a monomer or the like simply and efficiently out of stock solution containing solids of fine particle shape such as slurry or foamable stock solution. CONSTITUTION:Stock solution containing a low boiling material is diffusion sprayed in an upper chamber 2 of a sealed container 1 in which a porous plate 20 is inclinedly arranged and an upper chamber 20 and a lower chamber 22 are dividedly formed through a flash nozzle 3 and flash evaporated. Steam is fed into treatment liquid 23 remaining in the lower chamber 22 of the sealed container 1 and diffused over in the sealed container 1 by bubbling, and the diffused steam and the stock solution diffusion sprayed on the porous plate 20 are vapor-liquid contacted and the low boiling material such as a monomer group contained in the stock solution is thermally evaporated and separated.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a method and apparatus for separating low-boiling substances, and more particularly, to extracting synthetic resin monomers from a stock solution containing fine particulate solids such as slurry, or a foaming stock solution. The present invention relates to a method and apparatus for separating low-boiling substances, which are used to separate and recover low-boiling substances.

0002

2. Description of the Related Art Generally, in order to separate and recover low-boiling substances such as synthetic resin monomers from a stock solution containing particulate solids such as slurry, a low-boiling substance separation and recovery apparatus, for example, is used.
A distillation column is used. This distillation column includes a tray column and a packed column.

As shown in FIG. 5, a tray tower is a cylindrical sealed container (a) in which a plurality of perforated plates (c) with a large number of small holes (b) are spaced at predetermined intervals. Arranged horizontally in multiple stages, the stock solution flowing on the perforated plate (c) flows down to the perforated plate (c) below via overflow pipes (d) arranged vertically between each perforated plate (c). At the same time, the steam rising from below is passed through the small holes (b) of the perforated plate (c) to the perforated plate (c).
) A gas-liquid contact is made with the raw liquid flowing above, and this gas-liquid contact evaporates low-boiling substances such as monomers contained in the raw liquid, and the gas-liquid is separated into the treated liquid and low-boiling vapor. This is what I did. In addition, instead of a perforated plate, the above-mentioned tray tower has
There is a type of foam bell board in which foam bells are arranged at predetermined intervals in a plurality of stages in a horizontal position.

[0004] In addition, a packed tower is a cylindrical sealed container filled with an appropriate filler, and a stock solution containing low-boiling substances flows down inside the sealed container, and steam is blown up from below to separate the stock solution and steam. By bringing the liquid into gas-liquid contact, the low-boiling substances contained in the stock solution are evaporated and separated and recovered.

[0005]

[Problems to be Solved by the Invention] According to the conventional tray tower, the perforated plate (c) or the bubble bell plate is arranged in a horizontal position, and the overflow pipe (d) is arranged in a horizontal position. (c) Since it has an overflow weir (e) so that when the above-mentioned stock solution exceeds a certain height, water overflows and flows down, the stock solution contains particulate solids such as slurry. When the solids are treated on the perforated plate (c), etc., the solids are dammed up by the overflow weir (e), and as a result, the solids are precipitated on the perforated plate (c) and the small pores (
b) became clogged and gradually accumulated, resulting in a problem that it became unusable. A similar problem existed with packed columns.

[0006] Furthermore, when a stock solution having foaming properties is processed using the plate column or the like, bubbles are generated and the upper part of the sealed container is filled with foam, so that the stock solution does not flow. In order to process the raw solution smoothly, it is necessary to continuously inject antifoaming agents etc. into the sealed container, which increases the cost very much, and as a result, the tray column is not used for foaming. There was a problem in that it could not be used to treat undiluted solutions with

The present invention has been proposed in view of the above-mentioned problems, and it is possible to easily and efficiently extract low-boiling substances such as monomers from a stock solution containing fine particulate solids such as slurry, or a foaming stock solution. It is an object of the present invention to provide a method and apparatus for separating low-boiling substances that can be well separated and recovered.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the first invention provides an upper part of a sealed container in which an upper chamber and a lower chamber are partitioned by arranging a perforated plate at an angle inside the container. A stock solution containing low-boiling substances is diffused into the chamber through a flash nozzle to cause flash evaporation, and steam is supplied to the processing solution staying in the lower chamber to diffuse it into the sealed container by bubbling. The steam is brought into gas-liquid contact with the stock solution that has been diffused and sprayed onto a perforated plate to separate low-boiling substances.

[0009] A second invention provides a sealed container in which a perforated plate is arranged at an angle to form an upper chamber and a lower chamber, and a processing liquid is retained in the lower chamber so that it can be taken out from below; A flash nozzle is placed in the upper chamber above the perforated plate in the sealed container and diffusely sprays and flash-evaporates the stock solution containing low-boiling substances, and is placed immersed in the processing liquid in the lower chamber of the sealed container. and a steam supply pipe that blows out steam constitutes a low boiling point separation device.

0010

[Operation] The stock solution is diffused and sprayed downward from a flash nozzle located in the upper chamber of the sealed container, and low-boiling substances are instantly flash-evaporated. In addition, when steam is supplied into the processing liquid that has accumulated in the lower chamber of the sealed container, the processing liquid bubbles and the steam diffuses upward into the sealed container and rises. The stock solution on the perforated plate is heated and brought into gas-liquid contact, whereby low-boiling monomers contained in the stock solution are evaporated and separated and removed.

Furthermore, since the stock solution is blown out from the flash nozzle and the foaming foam is crushed by the showering action, foaming can be prevented even when the stock solution has foaming properties.

0012

EXAMPLES Examples of the low boiling point separation method and apparatus according to the present invention will be described below with reference to FIGS. 1 to 4.

In FIG. 1, (1) is a sealed container for separating and recovering low-boiling substances such as monomers from a stock solution containing fine particulate solids such as slurry. The introduction pipe (2) and the flush nozzle (3) are arranged, and the stock solution introduction pump (4) is installed in the middle of the introduction pipe (2).
), first flow rate control means (5), waste heat recovery heat exchanger (
6), stock solution heating means (7), and temperature control means (8)
A cyclone type mist separator (9) is arranged on the upstream side of the sealed container (1).
An outlet pipe (10) is provided at the lower end. The raw solution is passed through the waste heat recovery heat exchanger (
6) and the liquid heating means (7), the liquid is poured into a sealed container (1) by a flash nozzle (3).
) and then separated into a processing liquid and low boiling point vapor inside the sealed container (1), and the low boiling point vapor flows out to the mist separator (9).

The first flow rate control means (5) is provided between the stock solution introduction pump (4) and the waste heat recovery heat exchanger (6), and is configured to control the flow rate detected by the detector (11). Based on the value, the controller (12) controls the valve (13) to adjust the flow rate of the stock solution. In addition, the raw solution heating means (7) located downstream of the waste heat recovery heat exchanger (6) has a first steam supply means (15) connected to the small diameter part of the Venturi tube (14), and the raw solution heating means (7) is connected to the small diameter part of the Venturi tube (14). Steam is sucked out from the first steam supply means (15) by passing through the Venturi tube (14) to heat the stock solution. The heating temperature of the stock solution by the stock solution heating means (7) is controlled by the temperature control means (
8). This temperature control means (8) includes a detector (16) downstream of the stock solution heating means (7) and a first
The valves (17) are arranged at appropriate positions of the steam supply means (15), and the valves (17) are controlled by the controller (18) based on the detected temperature detected by the detector (16). ) to adjust the amount of steam supplied.

The sealed container (1) has a cylindrical shape with the lower end tapering downward, and has a perforated plate (20) with a large number of small holes (19) formed approximately in the center of the container.
are arranged at an angle to form an upper chamber (21) and a lower chamber (22).
), and the tapered end of the lower chamber (22) contains the processing liquid (2
3) An outlet (24) is provided for taking out the sample. The flash nozzle (3) is for diffusing and spraying the stock solution inside the sealed container (1), and is disposed through the upper chamber (21) of the sealed container (1), and is connected to the introduction pipe (2). It is connected to the stock solution heating means (7) via the straight pipe section (
A curved pipe portion (26) provided at the tip of the tube (25) is opened so as to face the perforated plate (20) tilted downward.

[0016] The curved pipe part (
The vertical length a of the straight pipe part (26) is as shown in FIG.
) is approximately equal to the inner diameter d of the curved pipe portion (26
) has an opening that will not be clogged with particulate solids such as slurry, and is eccentrically positioned within the sealed container (1) depending on the liquid quality. This amount of eccentricity is
As shown in FIG. 3, if the inner diameter of the sealed container (1) is D, then D:e=3:1 to 3:15. However, e is the shortest distance from the inner surface of the sealed container (1) to the curved pipe portion (26). By making the flash nozzle (3) eccentric in this way, the defoaming effect can be improved. Further, as shown in FIG. 4, a downstream pipe part (28) is formed between the hanging part (27) of the perforated plate (20) and the peripheral wall part of the sealed container (1). Perforated plate (20) through part (28)
The processing liquid flowing above is made to flow downward and stay in the lower chamber (22).

[0017] The outlet (24) of the sealed container (1) is
It is connected to the second medium passage of the waste heat recovery heat exchanger (6) via the outlet pipe (10). A recovery pump (29) is installed in the middle of the outlet pipe (10), and a sealed container (
The processing liquid (23) retained in the lower chamber (22) of 1) is transferred to the heat exchanger for waste heat recovery (
6). Lower chamber (22) of the above sealed container (1)
The level of the processing liquid (23) retained in the chamber is controlled by a liquid level control means (30). The liquid level control means (30)
The detector (31) is installed at the outlet (24) of the sealed container (1).
Further, a valve (32) is provided on the downstream side of the recovery pump (29), and the valve (32) is controlled by a controller (33) based on the detection result detected by the detector (31). The processing liquid (
23) Adjust the liquid level.

The mist separator (9) takes out the low boiling point vapor separated in the sealed container (1) through the take-out pipe (34) and further separates it into the processing liquid and the low boiling point vapor. The extraction pipe (34) connected to the mist separator (9) is passed through the sealed container (1), and the straight pipe part (3
The curved tube part (36) formed at the tip of the container (5) faces upward and faces the top wall of the sealed container (1). The outlet (37) at the lower end of the mist separator (9) is connected to the collection pipe (
The processing liquid (23) separated by the mist separator (9) passes through the inside of the recovery pipe (38). It is sent to the lower chamber (22) of the sealed container (1). In addition, the upper discharge port (39) of the mist separator (9) is connected to the discharge pipe (4).
0) to the first medium passage of the condenser (41), and the vapor containing low boilers separated by the mist separator (9) is transferred to the condenser (41) via the discharge pipe (40). to the first media path of the media. A cooling water pipe (42) is connected to the outlet and inlet of the second medium passage of the condenser (41).

A second steam supply pipe (43) is connected through the lower chamber (22) of the sealed container (1). The muffling nozzle (44) attached to the tip of the second steam supply pipe (43) faces downward and faces the lower outlet (24) of the sealed container (1), and is always connected to the processing liquid (44).
23). Sintered metal may be used for the muffling nozzle (44). The amount of steam supplied to the sealed container (1) is adjusted by the second flow rate control means (45). Second flow rate control means (4
5), a detector (46) and a valve (47) are arranged in the middle of the second steam supply pipe (43), and the detector (46)
The valve (47) is controlled by the controller (48) based on the detection result of the steam supply amount detected by the controller (48), and the processing liquid (
23) Supply a predetermined amount of steam into the chamber.

Next, the procedure for separating and recovering low-boiling substances, such as monomers, from a stock solution containing particulate solids such as slurry according to the present invention will be explained with reference to FIG. still,
Before monomer separation and recovery, the amount of liquid sent was 10 m3/
It is assumed that the stock solution of H contains 2000 ppm of monomer. Furthermore, the inside of the sealed container (1) is kept under a vacuum of, for example, about 290 mmHg in order to actively evaporate low-boiling substances such as monomers from the stock solution.

When the stock solution introduction pump (4) is driven, the stock solution is pumped to the waste heat recovery heat exchanger (6) while its flow rate is controlled by the first flow rate control means (5). The temperature of the stock solution is 10° C. before passing through the waste heat recovery heat exchanger (6), and is heated to 63° C. after passing through the waste heat recovery heat exchanger (6). This heated stock solution is passed through the Venturi tube (14) of the stock solution heating means (7).
It is assumed that the temperature is heated to 82° C. by the steam sucked out from the first steam supply means (15) while passing through. The Venturi tube (14) has a weight of 3 kg/cm.
It is assumed that steam with a pressure of 2G is sent at a rate of 340kg/H.

The temperature of the stock solution heated by the stock solution heating means (7) is controlled to a constant temperature by adjusting the amount of steam supplied from the first steam supply pipe (15) by the temperature control means (8). be done. The pre-heated stock solution is diffused and sprayed from the flash nozzle (3) into the sealed container (1), and as a result, the low-boiling monomers are instantaneously flash-evaporated and separated, and the remaining ones are left behind through the porous pores. Sprinkle in a shower over the entire area of the board (20).

On the other hand, it is assumed that steam at a pressure of 3 kg/cm2G is fed from the second steam supply pipe (43) at a rate of 160 kg/H to the lower chamber (22) of the sealed container (1). Then, the processing liquid (23) remaining in the lower chamber (22) of the sealed container (1) is bubbled, and 170 kg/H of steam rises upward while diffusing.
) is heated and brought into gas-liquid contact, and this heating and gas-liquid contact form the perforated plate (20).
Low-boiling substances in the above stock solution are evaporated and separated.

[0024] The monomer vapor separated from the stock solution is taken out to the mist separator (9) through the takeout pipe (34) disposed at the upper part of the sealed container (1). This monomer vapor is further separated into a processing liquid and monomer vapor by a mist separator (9), and 300 kg/h of monomer vapor is sent to a condenser (41) while passing through the first medium passage. It is cooled by cooling water and collected as condensate.

[0025] Furthermore, the processing liquid from which low-boiling substances have been separated inside the sealed container (1) flows over the inclined perforated plate (20) into the downflow pipe section (28), and then flows into the lower chamber (22). stay in. At this time, even if the processing liquid adhering to the surface of the perforated plate (20) contains fine particulate solid matter such as slurry, this solid matter is removed because the perforated plate (20) is tilted.
It flows down into the lower chamber (22) together with the processing liquid (23) along the surface of the perforated plate (20). Therefore, the perforated plate (20)
The small holes (19) are not clogged with particulate solid matter. Then, when the liquid level of the processing liquid (23) containing the fine particulate solids reaches a predetermined level and is detected by the liquid level control means (30), the processing liquid (23) is transferred to the recovery pump (29). ), the waste heat is pumped through the outlet pipe (10) to the waste heat recovery heat exchanger (6). The temperature of the treatment liquid (23) pumped at this time is 75°C, and the temperature of the treatment liquid (23) in the second medium passage of the waste heat recovery heat exchanger (6) is 75°C.
) and the stock solution, and the stock solution is heated to 63° C. as described above, and the temperature of the processing solution (23) becomes 23° C. before being recovered.

[0026] As mentioned above, the recovered processing liquid is
Since the monomer was removed by the sealed container (1) and the mist separator (9), the 2000 ppm of monomer contained in the stock solution with a flow rate of 10 m3/H was
It was 1 ppm.

In addition, when separating and recovering low-boiling substances such as monomers from a foaming stock solution, the stock solution is blown out from the flash nozzle (3) and the foaming foam is crushed by the showering action. Foaming can be reliably prevented. Therefore, even when processing a highly foaming stock solution, it can be applied without using an antifoaming agent.

[0028] In the above embodiment, the case where monomers are separated and recovered from the stock solution was explained, but the present invention is not limited to this, and the present invention is also applicable to the case where various low-boiling substances contained in the stock solution are separated and recovered. Can be widely applied.

[0029]

[Effects of the Invention] According to the present invention, the stock solution is diffused and sprayed into the upper part of the sealed container using a flash nozzle to evaporate and separate low-boiling substances, and furthermore, the perforated plate arranged at an angle in the lower part adds a heating distillation effect. The separation of low-boiling substances can be further improved. Since the perforated plate is arranged in an inclined manner inside the sealed container, the particulate solids contained in the stock solution flow down into the lower chamber along the inclined surface of the perforated plate. Therefore, clogging of the porous plate can be prevented. In addition, during gas-liquid separation, the steam supplied to the lower chamber of the sealed container is diffused and rises due to bubbling of the processing liquid, so that the stock solution on the perforated plate and the steam are definitely in gas-liquid contact, and the sealed container The stock solution introduced into the
Since gas-liquid separation is performed by both flash evaporation and gas-liquid contact with steam on a porous plate, low-boiling substances such as monomers can be efficiently separated and recovered from the stock solution. Furthermore, the structure is simple and the manufacturing cost is low. Further, since the flash nozzle has a defoaming effect, even if a stock solution having foaming properties is processed, foaming is prevented.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a flash nozzle.

FIG. 3 is an explanatory diagram of the amount of eccentricity of a flash nozzle.

FIG. 4 is a cross-sectional view of the sealed container.

FIG. 5 is an explanatory diagram of main parts showing a plate column which is a conventional low boiling point separation device.

[Explanation of symbols]

1 Sealed container 3 Flash nozzle 20 Porous plate 21 Upper chamber 22 Lower chamber 23 Processing liquid 43 Steam supply pipe

Claims (2)

[Claims] Claim 1: A stock solution containing a low-boiling substance is diffused and sprayed through a flash nozzle into the upper chamber of a sealed container in which an upper chamber and a lower chamber are partitioned by a perforated plate arranged at an angle.
At the same time as flash evaporation, steam is supplied to the processing solution staying in the lower chamber and diffused into the sealed container by bubbling, and the diffused steam and the stock solution diffused and sprayed on the perforated plate are brought into gas-liquid contact to reduce the A low boiling point separation method characterized by separating boiling points. Claim 2: A sealed container in which a perforated plate is disposed at an angle to form an upper chamber and a lower chamber, and a processing liquid is retained in the lower chamber so that it can be taken out from below; a flash nozzle disposed in an upper chamber above the perforated plate and configured to diffusely spray and flash evaporate a raw solution containing low-boiling substances; A low boiling point separation device consisting of a steam supply pipe that blows out steam.