JPH05111601A - Concentrator - Google Patents

Abstract

PURPOSE:To efficiently concentrate liquid from low viscosity to high viscosity. CONSTITUTION:A concentrator is constituted by an evaporator 1 communicating with a vacuum device, the 1st indirect heater 3 formed by e.g. a plate heat exchanger, and the 2nd indirect heater 4 equipped with a fixed agitator for stirring liquid to be treated and an indirect heating means inside and out respectively. They are connected as shown on the figure. At first the liquid to be treated is low in viscosity and concentrated by the 1st indirect heater 3 with good heat exchangeability. Then, when the liquid to be treated increases in viscosity, it is concentrated by the 2nd indirect heater without scorching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for efficiently concentrating a liquid having a low viscosity to a high viscosity.

[0002]

2. Description of the Related Art The applicant of the present invention has previously referred to a "concentrator" (Japanese Patent Laid-Open No. 63-63119).
-229101). This method aims at concentrating a high-viscosity liquid, and in order to prevent kogation due to an indirect heating device during circulation of the liquid, a fixed stirrer is installed in the indirect heating device to uniformly heat the concentrated liquid, It is a concentrating device configured to concentrate the liquid by both means of vacuum evaporation.

[0003]

However, in the above-mentioned conventional example, the purpose is to concentrate a liquid having a high viscosity, and in the case of concentrating a low-viscosity liquid to a high viscosity, it is an effective means. I could not say. As a result of intensive research to solve the problems of the prior art, the inventor of the present application has shown that when the liquid to be treated has a low viscosity, it is heated by a plate heat exchanger with good heat exchange efficiency because the liquid itself has good fluidity. However, when the viscosity increases to a certain degree, in order to prevent kogation, it was found that the liquid can be efficiently concentrated from a low viscosity to a high viscosity by heating with an indirect heating device having a fixed stirrer in its flow path. Was completed.

That is, according to the present invention, there is provided a first indirect heating device comprising a flow path for circulating a liquid to be treated and a heating means defined by the flow passage, and a fixed stirrer for stirring the liquid to be treated therein. A second indirect heating device comprising a flow path provided and an outer heating means defined by the flow path, and an evaporation device for evaporating the water content of the liquid to be treated under reduced pressure. And an evaporator are connected to each other via a forced circulation means.

[0005]

The present invention will be specifically described below with reference to the accompanying drawings. First, in FIG. 1, reference numeral 1 is an evaporation can equipped with a vacuum device 2 for evaporating the water content of a liquid to be treated under reduced pressure. Reference numerals 3 and 4 are a low-viscosity liquid circulation device and a high-viscosity liquid circulation device which are respectively installed in communication with the evaporator 1. The low-viscosity liquid circulation device 3 is a device that circulates a relatively low-viscosity liquid to be treated in the initial stage, and includes a low-viscosity circulation pump 5 and an indirect heating device 6. In particular, as the indirect heating device 6, it is preferable to form the indirect heating device 6 by a normal plate heat exchanger formed by sandwiching a large number of flat plates because the thermal efficiency is good.

The suction port 7 of the low-viscosity circulation pump 5 is an evaporator 1
Of the low temperature liquid circulation circuit, and its outlet 7A is in communication with the inlet 8 of the liquid to be treated in the indirect heating device 6, and the outlet 9 of the liquid to be treated is in communication with the evaporation can 1. Form 10. A stock solution tank 11 for supplying the liquid to be processed into the system is connected to the low-viscosity liquid circulation circuit 10 via a supply pump 12. 8
A and 9A are the inlet and outlet of the heating medium in the indirect heating device. Reference numeral 13 is a level control device for keeping the level of the liquid to be treated in the evaporator 1 at a certain fixed position.

Next, the high-viscosity liquid circulation device 4 has the function of further concentrating the liquid to be processed, which has increased in viscosity and becomes highly viscous, and has a high-viscosity circulation pump 14.
And a fixed stirrer 15 inside, and a pipe-shaped indirect heating device 16 provided with a heating jacket, that is, an outer cylinder 24 on the outer peripheral portion. The suction port 17 of the high-viscosity circulation pump 14 is connected to a three-way valve 19 provided in a pipe 18 that connects the evaporator 1 and the low-viscosity circulation pump 5. As shown in the figure, the other constitution of the high-viscosity liquid circulation device 4 is connected in the same manner as the low-viscosity liquid circulation device 3, and forms a high-viscosity liquid circulation circuit 20. In particular, in the high-viscosity liquid circulation circuit 20, a three-way valve 22 is provided in the pipe 21 that connects the indirect heating device 16 and the high-viscosity circulation pump 14 so that the concentrated liquid can be appropriately discharged. A viscometer 23 measures the viscosity of the liquid to be processed flowing through the pipe 18, controls the three-way valve 19, and directs the flow of the liquid to be processed from the low viscosity liquid circulation circuit 10 to the high viscosity liquid circulation circuit 20. Acts to switch. A Brix meter may be used instead of the viscometer. As this switching means, the differential pressure between the inlet 8 and the outlet 9 of the liquid to be treated in the indirect heating device 6 may be measured and the operation may be performed according to the value.

With such a structure, the liquid to be treated contained in the undiluted liquid tank 11 first has the low-viscosity liquid circulation circuit 10.
Is circulated in the circuit 10 by the action of the low-viscosity liquid circulation device 3. During the circulation, the liquid to be treated is concentrated by the heating by the indirect heating device 6 and the evaporation action by the evaporator 1.
Then, the viscosity of the liquid to be treated increases to some extent, and the viscometer 23 detects a state where it becomes difficult to flow through the indirect heating device 6, and the flow of the liquid to be treated is switched to the high viscosity liquid circulation circuit 20. Similarly, the liquid to be treated introduced into the high-viscosity liquid circulation circuit 20 is concentrated while circulating through the circuit 20, and when it reaches a specified value, the high-viscosity liquid circulation device 4 is stopped and the concentrated liquid is passed through the three-way valve 22. Collect.

In the concentrating device described above, the indirect heating device 16 is formed by connecting units 30A, 30B, 30C described later in series with a connecting pipe 31, and the units 30A, 30
The concrete shapes of B and 30C are as shown in FIGS.

The above unit will now be described with reference to FIGS. FIG. 2 is a diagram showing an example of a unit of the indirect heating device 16, and the unit 30 is composed of an inner cylinder 32 through which liquid flows and an outer cylinder 24 covering the outer circumference of the inner cylinder 32. Units are provided at both ends of the inner cylinder 32. Mounting flanges 34 and 35 for a connecting pipe 31 that connect 30 to each other are provided, and the outer cylinder 24
Of the inner cylinder 32 are formed so as to extend radially outward from the outer periphery in the vicinity of both ends of the inner cylinder 32, and an indirect heating medium inlet 38 is provided on the upper wall of one end of the outer cylinder 24. An indirect heating medium outlet 39 is formed in the lower end wall, and the space between the inner and outer cylinders serves as a heating medium passage 40.

A fixed stirrer 15 is provided in the liquid passage 41 in the inner cylinder 32. In the fixed stirrer 15, the plate stirrer as shown in FIG. 3 is twisted by 90 degrees about the center in the axial direction in the embodiment. It is composed of a spiral wing body 42, and a plurality of them are arranged in the axial direction with their phases shifted by 90 degrees in the axial direction.
FIG. 4 is a plan view of the blade body 42 of FIG. 3 seen from above. In FIG. 2, the blade body 42 is sequentially arranged axially in the passage 41 with a 90 ° phase shift. It is arranged over substantially the entire length.

A plurality of units 30 (30A, 30
B, 30C) are prepared and connected to each other so that the indirect heating medium inlet 38 and the indirect heating medium outlet 39 in front are connected to each other, and the indirect heating medium outlet 39 is connected to the indirect heating medium inlet 38 of the next stage unit.
Connected to the indirect heating medium inlet 38 of the final stage unit 30C to the indirect heating medium supply line 43, and the indirect heating medium outlet 39 of the first stage unit 30A to the discharge line 4.
Connect to 4. And the individual units 30A, 30B,
The end of the inner cylinder 32 of 30C is connected to the U-shaped connecting pipe 31,
The inner cylinder 32 of each unit 30A, 30B, 30C is connected for communication. The downstream end of the inner cylinder 32 of the first-stage unit 30A is connected to the high-viscosity circulation pump 14, and the downstream end of the final-stage unit 30C is connected to the evaporator 1 respectively.

The indirect heating medium used in the indirect heating device 16 is, for example, hot water or steam, and is made to flow from the supply line 43 to the indirect heating medium inlet 38 of the final stage 30C, and the heating medium is passed through the passages 40 of the respective units. Since it is connected at the outlet, it flows through each passage and is discharged from the indirect heating medium outlet 39 of the first-stage unit 30A to the discharge line 44, whereby the liquid in the inner cylinder 32 is indirectly heated. On the other hand, the liquid pumped from the high-viscosity circulation pump 14 flows from the upstream side to the downstream side in the passage 41 in the inner cylinder 32, and the fixed blade body 4 in the passage 41.
The liquid flow is twisted by 2 and is divided and twisted because the phase of the next stage is shifted by 90 degrees, for example, and this is repeated sequentially and efficiently stirred and sent to the downstream. Therefore, the liquid flow does not become a laminar flow, and the outer layer, the intermediate layer, and the inner layer move uniformly while being in contact with the inner wall of the inner cylinder 32, and are efficiently heat-exchanged and heated. ..

In the above, by selecting the number of blades 42 constituting the fixed stirrer 15, it is possible to set the heating under optimum conditions according to the physical properties of the liquid to be treated. Here, a modified example of the fixed agitator 15 of the indirect heating device in which the units are arranged in series will be described with reference to FIG. As is clear from FIG. 5, in this embodiment, a small-diameter shaft portion 48 having a sharp end in the direction opposite to the liquid flow is axially separated from the liquid passage 47 of the inner cylinder 46 of the unit 50. The blades 49 were provided radially on the outer periphery of the blades, were joined to the inner wall of the inner cylinder 46, and the blades 49 were twisted to form the fixed stirring mechanism 50. The liquid is agitated by the mechanism 50, the heating medium is circulated in the passage between the outer cylinder 51 and the inner cylinder 46, and the liquid is indirectly heated.

Next, a second embodiment of the concentrating device will be described with reference to FIG. FIG. 6 is a schematic diagram showing a second embodiment of the concentrating device. That is, in the concentrating device of the present embodiment, a plurality of units 30A, 30B, 30C shown in FIGS. 2 to 4 are prepared, and they are mutually inverted to connect the indirect heating medium inlet 38 and the indirect heating medium outlet 39 on the front side. One end of each of the integrated units 30A, 30B and 30C is connected to the connecting member 5
2 to the upstream pipe 18 and the other end to the downstream pipe 54 via the connecting member 53,
This is the same as the embodiment of FIG. 1 except that the units 30A, 30B and 30C are arranged in parallel to form the indirect heating device 16A.

Also in the above indirect heating device 16A, the liquid flowing through the inner tubes of the units 30A, 30B and 30C is
It will be agitated, and the units 30A, 30B,
By arranging 30C in parallel, the indirect heating device 16
The cross-sectional area of the liquid flow passage at A can be increased.

A third embodiment of the concentrating device will be described with reference to FIG. FIG. 7 is a schematic diagram showing an example using a multi-tube cylindrical heat exchanger. That is, the concentrating device of the present embodiment,
As the indirect heating device 16C, a plurality of small-diameter inner pipes 58 for circulating the liquid to be treated are provided in a large-diameter cylindrical outer pipe 57 whose both ends are closed by closing lids 55 and 56 and which penetrate the pipe 57 in parallel with its axis. Using the multi-tube cylindrical heat exchanger provided with the predetermined intervals, the fixed stirrer 15 similar to that of the second embodiment is provided in the inner tube 58, and one end of each inner tube 58 is provided. Connecting part 5
The concentrator of FIG. 1 is the same as that of FIG. 1 except that the high-viscosity circulation pump 14 is communicated with the evaporator 1 via the connecting member 60 and the other end is communicated with the evaporator 1 via the connecting member 60.

In the above indirect heating device 16C, the indirect heating medium flowing from the supply line 43 into the outer pipe inlet portion 61 passes through the space between the inner pipes 58 and is discharged from the outer pipe outlet portion 62 to the discharge line 44. It Such indirect heating device 16
According to C, since the inner tubes 57 can be arranged in parallel and arranged in a large number, it is possible to obtain a larger liquid flow channel area than the indirect heating device 16B in the second embodiment.

[0019]

As described above, according to the present invention,
Both a plate type indirect heating device with good heat exchange efficiency and an indirect heating device with a fixed stirrer are installed, the former process liquid to be treated at a relatively low viscosity, and the latter process liquid with high viscosity. Since it is configured to process, the concentration operation can be performed efficiently, and kogation does not occur in each indirect heating device.

[0020]

[Brief description of drawings]

FIG. 1 is a schematic diagram of a concentrating device of the present invention.

FIG. 2 is a front sectional view of a unit of an indirect heating device.

FIG. 3 is a front view of a blade of a fixed stirring device.

FIG. 4 is a plan view of an impeller of a fixed stirring device.

FIG. 5 is a front sectional view of a unit of an indirect heating device.

FIG. 6 is a schematic diagram of another embodiment.

FIG. 7 is a schematic diagram of another embodiment.

[0021]

[Explanation of Codes] 1 Evaporator 2 Vacuum device 3 Low viscosity liquid circulation device 4 High viscosity liquid circulation device 5 Low viscosity circulation pump 6 Indirect heating device 10 Low viscosity liquid circulation circuit 11 Stock solution tank 13 Level control device 14 High viscosity circulation pump 15 Fixed Stirrer 16 Indirect Heating Device 20 High Viscosity Liquid Circulation Circuit 23 Viscometer 30 Unit 38 Indirect Heating Medium Inlet 39 Indirect Heating Medium Outlet

Claims (1)

[Claims] 1. A first indirect heating device comprising a flow path for circulating a liquid to be treated and a heating means defined by the flow passage, and a flow having a fixed stirrer therein for stirring the liquid to be treated. A second indirect heating device comprising a channel and an outer heating means defined by the flow channel, and an evaporation device for evaporating the water content of the liquid to be treated under reduced pressure, and each of the indirect heating device and the evaporation device. A concentrating device characterized in that the fluid is communicated via a forced circulation means.