JPH0641605Y2 - Thin film evaporator - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention removes residual volatile components such as monomers and solvents from a high-viscosity liquid polymer resin obtained by a polymerization reaction to obtain a purified product. The present invention relates to an improvement of a forced thin film evaporation device that is advantageously used for such purposes.

(Prior Art) FIG. 4 shows a prior art thin film evaporation apparatus which is to be compared with the present invention.

The heat medium is passed through the heat medium nozzles (4) and (5) to a jacket (3) provided with the inner surface (2) of the cylindrical hermetic evaporator body (1) around the central longitudinal axis (X) on the outer periphery. It is formed on the heating / evaporating surface by passing it through, and the vapor outlet nozzle (6) of the volatile component vapor in the upper part is connected to the vacuum source via the condenser outside the device, thereby making it possible to reduce the pressure and vacuum inside the device. ,
The dispersion unit (10) is attached to the upper side of the rotary shaft (9) supported by the upper and lower bearings (7) and (8) at the central vertical axis (X) position, and the thinning unit (11) is attached to the lower side of the rotary shaft (9), and the liquid material inlet nozzle ( A liquid material containing a volatile component supplied from the (12) toward the dispersion unit (10) in the vessel is primarily dispersed all around the inner surface of the vessel by the dispersion unit (10) and transferred downward to form a thin film. The thinning blades (13) arranged in a row on the outer periphery of the unit (11) forcibly develop a thin film on the heating / evaporating surface and forcibly scrape it, thus removing volatile components from the liquid material thin film on the heating / evaporating surface. The heating temperature is made as low as possible under reduced pressure to rapidly evaporate and remove from a wide evaporation area under a short heat influence time to purify the liquid material. The product purified in this way is extracted from the product outlet (14) at the lower end of the evaporator body, while the vapor of volatile components generated in the thinning evaporation section (A) in the area of the thinning unit (11) is in the upper dispersion unit. After passing through the steam passage (15) provided in the above, the steam is discharged from the steam outlet nozzle (6) to the outside and condensed and liquefied by the condenser.

(Problems to be Solved by the Invention) Although the above-mentioned prior art thin-film evaporator can make the purification purity of the product much higher than that of other kinds of evaporators, it is nevertheless practical. Theoretically, it was difficult to stably obtain a homogeneous product with an ultra-high purity that should be attainable.

As a result of investigating the cause, the following reason was found. That is, in this type of thin film evaporator, particularly when the liquid material has high viscosity and the degree of vacuum inside the chamber is increased, the volatile component evaporates and foams in the thin film liquid material on the heating evaporation surface in the thin film evaporation section. When the bubbles leave the thin film surface and exit into the gas phase, the liquid material is scattered due to the bubble breakage. The agitation action by the thinning blade promotes this. This droplet is entrained in the vapor of the volatile component.

The temperature of the vapor of the volatile component is the vaporization temperature of the heating evaporation surface, and this temperature is also the condensation temperature.Therefore, if this vapor comes into contact with parts below the condensation temperature inside the container before it goes out of the container, the surface of these parts And the entrained liquid material droplets adhere and accumulate. The condensate of volatile components adhering to the rotary member in the area of the thin film evaporation section (A) returns to the thin film liquid material on the heating evaporation surface by the action of centrifugal force and is recycled to repeat the above liquid material splashing phenomenon. The deposited and deposited liquid material is affected by heat during the deposition time and deteriorates to that extent, and then mixes into the purified liquid material, which causes non-uniformity of the product. as a result,
It is difficult to carry out high-purity and homogeneous purification of the liquid material as planned within a short time of one pass of forcedly scraping the liquid material thin film.

Further, the adhered deposits on the rotating member may cause mechanical imbalance, which may make it impossible to perform continuous operation smoothly.

(Means for Solving Problems) Based on the findings of the above-mentioned search results, the present invention proposes an improvement to cut off the separation and united recycling of volatile components and liquid materials occurring in the thin film evaporation section of the thin film evaporator. The purpose of the addition is to realize a thin film evaporation device with more advanced functions.

As a means for this, the supporting part of the thinning blade, which is a rotating member in the thinning evaporation part, and the rotating shaft are made hollow, and a heating medium is circulated in the hollow to heat the surface, and the surface temperature of these is condensed to condense volatile component vapors. The temperature is set to be equal to or higher than the temperature so that the evaporation and separation component does not condense on the rotating member and the liquid component droplet does not adhere and accumulate. The part of the dispersion unit in the middle of the heat medium circulation path will also be heated.

Circulation of the heat medium for this heating may be performed from the rotary joint above the rotary shaft via the double pipe supply / discharge pipe line in the rotary shaft, and it can be easily performed by sharing the jacket heat medium. It is possible and does not cause inconvenience of temperature-related control.

That is, the thin film evaporator of the present invention has a jacket formed on the outer circumference of the inner surface of a cylindrical decompressible closed evaporator main body formed around the central longitudinal axis, and the heating medium nozzle disposed in the jacket. A heating medium is circulated to heat the inner surface of the vessel to form a heating and evaporating surface, and a dispersion unit that rotates above the rotation axis at the central longitudinal axis position is disposed inside the heating and evaporating surface. Downwardly inclined spiral fins are arranged on the outer periphery of the dispersion unit, and a rotating forced thinning unit is disposed below the rotation shaft, and the forced thinning unit is the dispersion unit. A plurality of supporting portions extending downward from the outer peripheral portion of the lower end of the rotating shaft to the lower end of the rotary shaft are provided, and spirally thinned blades with a downward inclination are formed in a row on the outer side thereof, whereby, Outside the dispersion unit The liquid material to be supplied is primarily dispersed over the entire circumference of the inner surface of the vessel by the rotating dispersion unit, and then the liquid material is provided by the rotating forced thinning unit disposed below the rotation shaft. In a thin film evaporation device configured to be secondarily expanded in a thin film on the heating and evaporation surface, the dispersion unit, the supporting portion supporting the thinning blade of the thinning unit and the rotating shaft are communicated as a hollow, It is characterized in that a heat medium circulation passage is formed in the dispersion unit, the support portion, and the rotation shaft.

Further, the present invention is characterized in that, in the above-mentioned thin film evaporation apparatus, a vapor passage is provided in the upper dispersion unit.

Furthermore, the present invention is characterized in that, in the above-mentioned thin film evaporation apparatus, the rotating shaft is a double tube and forms an outer flow path and a central flow path.

(Operation) In the present invention, the vapor of the volatile component evaporated from the liquid material thinned on the heating and evaporating surface in the area of the thin film evaporating portion of the thin film evaporator does not condense on the rotating member and is recycled. , Due to this, scattering of liquid material, adhesion,
This has the effect of reducing the chances of accumulation, alteration, and contamination, which leads to a further improvement in the degree of purification of the product and a further homogenization of the product.

(Embodiment) Hereinafter, the present invention will be specifically described with reference to FIGS.

FIG. 1 is a vertical sectional side view showing the whole thin film evaporation apparatus of one embodiment of the present invention, FIG. 2 is a plan view of its rotating member, and FIG. 3 is a vertical sectional side view taken along the line III-III in FIG. Is.

The basic structure of this thin film evaporator is almost the same as that of the prior art, and the inner surface (2) of the cylindrical closed evaporator main body (1) is attached to the outer periphery around the central longitudinal axis (X). The heating medium is passed through the heating medium nozzles (4) and (5) through the jacket (3) to form a heating evaporation surface, and the vapor outlet nozzle (6) for the volatile component vapor in the upper portion is connected to the outside condenser. After that, by connecting to a vacuum source (not shown), it is possible to reduce the pressure and evacuate the inside of the vessel, and the rotary shaft (9A) supported by the upper and lower bearings (7) and (8) at the central vertical axis (X) position. ) Upper part of the dispersion unit (10A), lower part of the thinning unit (11A)
The liquid material supplied from the liquid material inlet nozzle (12) into the vessel is dispersed by the dispersing unit (10A) over the entire circumference of the inner surface of the vessel, and then the thinning blade (1A) of the thinning unit (11A) is
By 3), a volatile component contained in the liquid material is vaporized by spreading it in a thin film on the heating evaporation surface.

In this embodiment, as shown in FIGS. 2 and 3, the dispersion unit (10A) is provided with a downward sloping portion on the outer circumference of the base cylindrical portion (16) for the entire circumference dispersion and descending of the liquid feeding material in the container. The fins (17) composed of spirals are arranged in a row, and the upper and lower plate parts (18) and (19) whose outer edges are spaced apart from the inner surface (2) of the vessel by the upper and lower edges are integrally connected to each other to form a rotary shaft at the inner edges. In this example, four steam passages (15A) are provided, which are connected to (9A) and are formed into a hollow closed plate shape, and vertically penetrate through and open inside.
In the present invention, the hollow space inside the dispersion unit (10A) is used for the heat medium passage as described later.

In this example, the thinning unit (11A) has four symmetrically arranged L-shaped arms extending downward from the outer peripheral portion of the lower plate portion (19) of the dispersion unit and reaching the manifold (20) at the lower end of the rotating shaft. The support portion (21) is provided and the thinning blades (13) are arranged in a row outside the support portion (21). In the present invention, the support part (21) is hollow and communicates with the internal space of the dispersion unit (10A).

Thus, in the thinning evaporation section (A) in the area of the thinning unit (11A), the vapor of the volatile component evaporated from the liquid material spread in a thin film on the heating evaporation surface is the vapor passage (15A).
Through the steam outlet nozzle (6) to the outside of the device. On the other hand, the thin film of the refined product is scratched down by the thinning blade (13) and taken out from the product through the product outlet (14) at the lower end.

In order to implement the present invention, when steam is used as a heat medium, the rotating shaft (9A) is a double tube and has an outer flow path (9a) and a central flow path (9b).
And a rotary joint (22) connected to these flow paths is provided on the outside of the device. In the inner diameter passage, steam introduced from the outer heat medium passage (23) enters the outer passage (9a) of the double pipe through the rotary joint (22), and part of it flows down to the lower end as it is from the inside. The temperature of the outer surface of the rotating shaft (9A) in the thin film evaporation section (A) is maintained above the condensation temperature of the volatile component vapor by heating the other part, and the other part is branched from the middle and dispersed from the through hole (24). The outer surface of the unit (10A) enters the hollow space that functions as an inlet manifold, branches from the hollow space, flows down through the hollow passages of the four thin film blade support portions (21), and is heated from the inside to the outer surfaces thereof. Is also maintained above the condensation temperature. Waste steam and drain generated by heating pass through the holes (25) (26) and the central flow path (9b) of the double pipe.
Rise through the rotor joint (22) and the heat transfer path (2
It is connected so as to lead out from 7).

By the circulation of the heat medium, the outer surface temperature of the rotating member such as the blade support portion (21) and the rotating shaft (9A) in the thin film evaporation portion (A) is maintained above the condensation temperature of the volatile component vapor. Condensation does not occur, the deposition of entrained liquid component droplets is prevented, the recycling of these in the thin-film evaporation section (A) is prevented, and the degree of purification of the product is high so that inhomogeneity is not caused. The dispersion unit (10A), which plays the role of the inlet manifold, is also heated and its lower surface and the steam passage (15A) reach the condensation temperature or higher. Therefore, the tendency of the steam passage to be blocked by deposits is prevented, and the vacuuming effect is reduced The problem of imbalance is also solved.

The present invention is not limited to the above embodiment, but can be implemented with various modifications. For example, when hot water is used as the heat medium, the flow passage direction may be opposite to that of the steam direction.

(Effect of the Invention) As described above, according to the present invention, by keeping the surface temperature of the rotating member in the thin-film evaporation section at the condensation temperature of the volatile component or more, the condensation and the entrained liquid component splash accumulation are prevented, It has the effect of blocking their recycling, increasing the degree of purification of the product and maintaining it homogeneous.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing the overall construction of a thin film evaporation apparatus according to one embodiment of the present invention, FIG. 2 is a plan view of its rotating member, and FIG. 3 is its sectional view taken along line III-III in FIG. FIG. 4 is a vertical side view of a prior art thin film evaporation apparatus which is to be compared with the present invention. (1) …… Evaporator body, (2) …… Inner surface, heating / evaporating surface, (3) …… Jacket, (4) (5) …… Heating medium nozzle, (6) …… Steam outlet nozzle, ( 7) (8) …… Bearing, (9) (9A) …… Rotary shaft, (9a) …… Outside flow path,
(9b) ... central flow channel, (10) (10A) ... dispersion unit, (11) (11A) ... thinning unit, (12) ... liquid material inlet nozzle, (13) ... thinning blade , (14) …… Product outlet, (15) (15A) …… Steam path, (16) …… Base cylinder part, (17) …… Fin, (18) …… Upper plate part, (19)…
… Lower plate, (20) …… Manifold, (21) …… Support, (23) (27) …… Heat carrier path, (24) (25) (26)…
... through hole, (X) ... central vertical axis, (A) ... thin film evaporation portion.

Claims (3)

[Scope of utility model registration request] 1. A jacket is formed on the outer periphery of the inner surface of a cylindrical type decompressible closed evaporator main body formed around a central longitudinal axis, and a heat medium is discharged from a heat medium nozzle arranged in the jacket. A circulation unit is circulated to heat the inside surface of the vessel to form a heating evaporation surface, and a dispersion unit that rotates above the rotation axis at the central vertical axis position is disposed inside the heating evaporation surface. A spiral fin having a downward inclination is arranged in a row, a rotating forced thinning unit is disposed below the rotation shaft, and the forced thinning unit is arranged at the outer periphery of the lower end of the dispersion unit. A plurality of supporting portions extending downward from the lower portion to the lower end of the rotating shaft are provided, and spirally thinned blades with a downward inclination are formed in a row outside the supporting portions, whereby the dispersion unit is provided. Liquid material supplied from outside the device After being dispersed by the rotating dispersion unit over the entire circumference of the inner surface of the vessel, the liquid material is spread on the heating evaporation surface by the rotating forced thinning unit disposed below the rotation shaft. In a thin film evaporation device configured to be subsequently developed into a thin film, the dispersion unit, a supporting unit that supports the thinning blade of the thinning unit and a rotating shaft communicate with each other as a hollow, and the dispersing unit, the supporting unit, and A thin-film evaporation device, characterized in that a heat medium circulation passage is formed in the rotating shaft. 2. The thin film evaporation apparatus according to claim 1, wherein a vapor passage is provided in the upper dispersion unit. 3. The thin film evaporation apparatus according to claim 1, wherein the rotary shaft is a double tube and forms an outer flow path and a central flow path.