JPH05261202A - Thermocompression evaporator - Google Patents

Abstract

(57) [Summary] [Objective] The purpose is to facilitate the control at the time of starting the vapor compression type evaporator and to simplify the entire apparatus. [Composition] The vapor compressor of the vapor compression evaporator is driven by a motor controlled by an inverter to make the rotation speed of the vapor compressor itself variable, and when the vapor compression evaporator is started, it is synchronized with the increase in the amount of vapor generated. By increasing the rotation speed of the vapor compressor, facilitating the control at the start, and
This is a simplification of the entire device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor compression type evaporator, and more specifically, at the time of starting the vapor compression type evaporator, the number of revolutions of a vapor compressor is increased according to the amount of vaporized vapor generated. The present invention relates to such a vapor compression type evaporator.

[0002]

2. Description of the Related Art FIG. 2 shows a vapor compression evaporator (1) for concentrating a stock solution of an aqueous solution.

In the figure, (2) is an evaporator for heating and evaporating the stock solution supplied to the first flow path (A), and (3) is the first flow path of the evaporator (2). This is a separator for performing gas-liquid separation of the stock solution containing the evaporative vapor discharged from (A), and separating the stock solution into the evaporative vapor and the concentrated solution.

(4) preheats the stock solution supplied to the evaporator (2) and cools the evaporation vapor by the evaporation vapor discharged from the second flow path (B) of the evaporator (2). Vent condenser for (5) is the second flow path (B) of the evaporator (2)
And a drain pot for separating vaporized vapor and vapor drain discharged from the vent condenser (4).

Reference numerals (6) and (7) denote a vacuum device and a condensed water pump which communicate with the drain pot (5). The vacuum device (6)
As a result, the air generated in the drain pot (5) is discharged to the atmosphere, and the drain separated in the drain pot (5) is discharged to a predetermined location.

Reference numeral (8) is a circulation pump for returning the concentrated liquid separated in the separator (3) to the evaporator (2) and sending it to a concentrated liquid tank (not shown).

(9) sucks and compresses the evaporation vapor generated in the separator (3) to serve as a heat source for the evaporator (2).
The vapor compressor for supplying into the second flow path (B) of the, and (10) is the vapor compressor of the evaporative vapor.
Inlet vane for adjusting the inhalation volume to (9), (1
1) is an inlet vane operating device for operating the inlet vane (10).

(12) is a motor for driving the vapor compressor (9), and (13) is a gear type speed increasing ratio interposed between the motor (12) and the vapor compressor (9). It is a speed increaser.

Reference numeral (14) is a bypass valve interposed in a bypass flow passage (15) for returning the evaporation vapor discharged from the second flow passage (B) of the evaporator (2) into the separator (3). , (16) are bypass valve operating devices for operating the bypass valve (14).

In the above structure, in order to concentrate the stock solution, first, the stock solution is supplied into the apparatus and then the bypass valve is used.
(14) is fully opened and the inlet vane (10) is squeezed to the minimum, and then the condensed water pump (7), the circulation pump (8) and the vapor compressor (9) are driven.

Undiluted solution from the vent condenser (4) to the evaporator
When it flows through the first flow path (A) of (2) and into the separator (3), this undiluted solution is again caused by the action of the circulation pump (8) to the first flow path (A) of the evaporator (2). The cycle in which it is returned to is repeated.

On the other hand, the air in the separator (3) is sucked by the vapor compressor (9) and then the evaporator.
The cycle of (2) returning from the second flow path (B) to the separator (3) through the bypass flow path (15) is repeated.

Then, while the above two cycles proceed simultaneously, the stock solution in the separator (3) gradually begins to evaporate, and the evaporative vapor is suction-compressed by the vapor compressor (9) and then the evaporator ( The undiluted solution that is supplied to the second flow path (B) of 2) and is heated by the compressed evaporation vapor in the first flow path (A) of the evaporator (2) is heated in the separator (3). When the liquid separation is performed and the stock solution is concentrated, the bypass valve (14) is gradually closed first, and then the opening of the inlet vane (10) is gradually increased as the amount of evaporative vapor increases. The control to increase it is performed, and the operation shifts to steady operation.

Thus, the vapor compression type evaporator (1)
When the normal operation starts, the undiluted solution supplied to the first flow path (A) of the evaporator (2) is heated and evaporative vapor and concentrated solution are formed in the first flow path (A).

The evaporative vapor and the concentrated liquid are separated into gas and liquid in the separator (3), the concentrated liquid is sent to the concentrated liquid tank, and a part of the concentrated liquid is again supplied to the first flow path of the evaporator (2).
Supplied to (A).

The evaporative vapor separated in the separator (3) is sucked and compressed by the vapor compressor (9) and then supplied to the second flow path (B) of the evaporator (2) to evaporate the stock solution. Used as a heat source.

Further, the drain of the evaporation vapor discharged from the second flow path (B) of the evaporator (2) is directed to the drain pot (5), and the remaining evaporation vapor is used for preheating as a vent condenser.
After being sent to (4), it flows into the drain pot (5), gas-liquid separation is performed, the non-condensable gas is the vacuum generator (6), and the drain is the condensed water pump (7). Will be drained to a specified location.

[0018]

[PROBLEMS TO BE SOLVED BY THE INVENTION] Vapor compression type evaporator
If (1) is configured as described above, the vapor compressor (9) can be used until the vapor compression evaporator (1) enters steady operation.
Since the rotation speed of the evaporator cannot be changed, the second flow path (B) of the evaporator (2)
And an inlet vane (10) provided immediately before the vapor compressor (9) while adjusting the opening degree of the bypass valve (14) interposed in the bypass flow passage (15) provided between the separator and the separator (3). By Vapor Compressor (9)

It is necessary to control the intake amount of the evaporation vapor to the separator (3) so that the evaporation vapor is efficiently generated in the separator (3).

However, there is a problem that it is a very difficult work to reliably control the above-mentioned two in accordance with the amount of evaporative vapor generated in the separator (3).

When the above control is performed, the bypass valve (14)
Also, a control mechanism for operating the inlet vane (10) and a bypass flow path (15) are required.
There was also a problem that the structure of (1) becomes complicated.

Furthermore, when the vapor compressor (9) is driven by the motor (12) through the speed increaser (13), the motor (12) is driven even if an appropriate starting device, for example, a starting device adopting the reactor starting method is used. ), A large current flows at the time of starting, so there was also a problem that it was necessary to enlarge the power receiving equipment.

[0023]

[Means for Solving the Problems] A vapor of a type in which vaporized vapor generated in a separator arranged on the downstream side of an evaporator is suction-compressed by a vapor compressor, and the vaporized vapor sucked and compressed is used as a heat source of the evaporator. In the compression type evaporator,

As a drive source of the vapor compressor, a motor composed of a high-speed rotating induction motor is used,
An inverter device is used as the rotation speed control means of the motor, and the rotation speed of the motor is increased in accordance with the increase amount of the evaporation vapor generated in the separator when the vapor compression evaporation device is started.

[0025]

As described above, by driving the vapor compressor by the motor controlled by the inverter, the rotation speed of the vapor compressor itself can be made variable to simplify the entire apparatus and facilitate the control at the time of starting. Is.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a vapor compression type evaporator (2
FIG. 3 is a block diagram showing the overall configuration of 1).

In the figure, (22) is an evaporator for heating and evaporating the stock solution supplied to the first flow path (A), and (23) is
This is a separator for performing gas-liquid separation of a stock solution containing evaporative vapor discharged from the first channel (A) of the evaporator (22) to separate it into an evaporative vapor and a concentrated solution.

The reference numeral (24) preheats the stock solution supplied to the evaporator (22) by the evaporation vapor discharged from the second flow path (B) of the evaporator (22) and cools the evaporation vapor. The vent condenser for (25) is the second flow path of the evaporator (22).
It is a drain pot for separating drain from the evaporation vapor discharged from (B).

Reference numerals (26) and (27) denote a vacuum device and a condensed water pump communicating with the drain pot (25).
By 6), the air separated in the drain pot (25) is discharged to the atmosphere, and the drain separated in the drain pot (25) is discharged to a predetermined place by the condensed water pump (27). ..

Reference numeral (28) is a circulation pump for returning the concentrated liquid separated in the separator (23) to the evaporator (22) and sending it to a concentrated liquid tank (not shown). The members are the same as conventional ones.

The numeral (29) sucks and compresses the evaporation vapor generated in the separator (23) to serve as a heat source for the evaporator (22).
It is a vapor compressor for supplying to the second flow path (B) of (22).

This vapor compressor (29) is configured so that the rotation speed of the compressor itself can be changed by the action of a motor (30) and an inverter device (31) which will be described later. It is not necessary to dispose an inlet vane immediately before and to provide a bypass passage or a control valve between the evaporator and the separator.

(30) is the vapor compressor (29)
It is a motor for driving, and this motor (30)
An induction motor capable of high speed rotation of 20,000 rpm or more is used.

(31) is an inverter device for controlling the rotation speed of the motor (30). In this embodiment, the inverter device (31) changes the rotation speed of the motor (30) to 3 ,.
600 rpm to 24,000 rpm (0 to 400 Hz)
I am trying to speed up.

In the above structure, in order to concentrate the stock solution by the vapor compression type evaporator (21) according to the present invention, the condensed water pump (27) and the circulation pump (28) are driven and the motor (30 ) Is started at a low speed by the action of the inverter device (31), so that the vapor compressor (29) whose drive source is the motor (30) is started at a low speed.

Undiluted solution from the vent condenser (24) to the evaporator
When it flows into the separator (23) through the first flow path (A) of (22), this stock solution is again acted by the circulation pump (28) to the first flow path (A) of the evaporator (22). The cycle in which it is returned to is repeated.

On the other hand, since no vaporized vapor is generated in the separator (23) at this time, the vapor compressor (29) sucks and compresses the air in the separator (23), and the sucked and compressed air is sucked and compressed. The second flow path of the evaporator (22)
It is supplied to (B), and the circulation flow is heated and heated.

When the evaporation vapor gradually starts to be generated from the stock solution in the separator (23) while the above two cycles proceed simultaneously, the motor (30) is synchronized with the generation of the evaporation vapor. The number of revolutions is increased to increase the number of revolutions of the vapor compressor (29), and the suction compression of the evaporation vapor by the vapor compressor (29) is gradually increased.
Supply to the second flow path (B) is increased.

Then, the stock solution flowing through the first flow path (A) of the evaporator (22) is heated by the heat of the evaporation vapor, gas-liquid separation is carried out in the separator (23), and the stock solution is concentrated. When the amount of evaporative vapor generated in the separator (23) increases, the rotational speed of the motor (30) is gradually increased as the amount of evaporative vapor increases, and the rotational speed of the vapor compressor (29) increases. Increase and finally shift to steady operation.

Thus, the vapor compression type evaporator (21)
When the normal operation starts, the undiluted solution supplied to the first channel (A) of the evaporator (22) is heated, and evaporative vapor and concentrated solution are formed in the first channel (A).

The evaporative vapor and the concentrated liquid are gas-liquid separated in the separator (23), the concentrated liquid is sent to the concentrated liquid tank, and a part of the concentrated liquid is again fed to the first flow path of the evaporator (22).
It is supplied to (A) and circulated.

The evaporative vapor separated in the separator (23) is sucked and compressed by the vapor compressor (29) and then supplied to the second flow path (B) of the evaporator (22) to evaporate the stock solution. Used as a heat source.

Further, the drain of the evaporation vapor discharged from the second flow path (B) of the evaporator (22) goes to the drain pot (25), and the remaining evaporation vapor goes to the vent condenser (24) for preheating. After being sent, it flows into the drain pot (25), gas-liquid separation is performed, and the non-condensable gas is transferred to the vacuum generator (26).
Further, the drain is drained to a predetermined place by the condensed water pump (27).

Incidentally, in the above embodiment, the vapor compressor (29) at the time of starting the vapor compression type evaporator (21).
The rate of increase in the number of revolutions may be set in advance by experiments or the like.

[0045]

As described above, in the vapor compression type evaporator according to the present invention, the vapor compressor for sucking and compressing the evaporation vapor generated in the separator and using it as the heat source of the evaporator is rotated by the inverter device. Since it is driven by a controlled motor, the number of revolutions of the vapor compressor can be increased in accordance with an increase in the amount of vaporized vapor that begins to be generated in the separator at the time of starting the vapor compression type evaporator.

Therefore, as in the conventional vapor compression type evaporator, an inlet vane is arranged immediately before the vapor compressor, and a bypass passage having a bypass valve is provided between the second passage of the evaporator and the separator. Since it is not necessary to control both the inlet vane and the bypass valve at the same time at the time of starting the vapor compression evaporation device, the control at the time of starting the vapor compression evaporation device becomes very easy and at the same time,
The structure of the entire device is also very simple.

Further, if the motor for driving the vapor compressor is controlled by an inverter, the motor is rotated at a low speed at the time of starting the motor, so that a large current does not flow at the time of starting the motor. Can be downsized, and as a result, the cost of the vapor compression evaporator can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a vapor compression evaporation device according to the present invention.

FIG. 2 is a block diagram showing a conventional example of a vapor compression evaporation device.

[Explanation of symbols]

 21 Vapor Compression Type Evaporator 22 Evaporator 23 Separator 29 Vapor Compressor 30 Motor 31 Inverter A First Channel B Second Channel

Claims (1)

[Claims] 1. A vapor compression evaporation apparatus of a type in which an evaporation vapor generated in a separator arranged on the downstream side of an evaporator is suction-compressed by a vapor compressor and the suction-compressed evaporation vapor is used as a heat source of the evaporator. In this case, a motor composed of a high-speed rotation type induction motor is used as a drive source of the vapor compressor, and an inverter device is used as a rotation speed control means of the motor. A vapor compression type evaporator characterized in that the number of rotations of a motor is increased according to the amount of evaporation vapor generated.