JP7435349B2 - distillation equipment - Google Patents

Description

The present invention relates to a distillation apparatus, and particularly to a distillation apparatus using a heat pump.

An example of a distillation apparatus using a heat pump is shown in FIG.

Raw water introduced into the distiller 1 via a supply line (not shown) is sent from the distiller 1 to a heat exchanger 4 via a pump 2 and piping 3, and is heated in the heat exchanger 4. After that, it is returned to the top of the distiller 1 via piping 5, and steam is generated. The upper part of the distiller 1 is sucked by a suction device 11, and the steam in the distiller 1 is introduced into a heat exchanger 7 via piping 6, cooled, and then transferred to condensed water via piping 8. The water is introduced into a tank 9 and separated into steam and water. The condensed water accumulates in the condensed water tank 9 and is taken out from the lower part of the condensed water tank 9 via a take-out line (not shown). The upper part of the condensed water tank 9 is connected to a suction device 11 via a pipe 10.

High temperature water from the heat pump system 12 is passed through the heat source fluid passage 4a of the heat exchanger 4, and low temperature water from the heat pump system 12 is passed through the heat source fluid passage 7a of the heat exchanger 7.

The heat pump 20 of the heat pump system 12 has a well-known configuration, in which a heat medium such as a fluorocarbon substitute from an evaporator 21 is adiabatically compressed by a compressor 22 to be heated to a high temperature and introduced into a condenser 23. is introduced into the evaporator 21 via the expansion valve 24, and is adiabatically expanded to lower the temperature.

Water in a hot water tank 30 is passed through a heat transfer tube 23a provided in a condenser 23 via a pump 31 and piping 32, and is heated by exchanging heat with a high-temperature heat medium. The heated water becomes high-temperature water and is returned to the hot water tank 30 via piping 33.

The high-temperature water in the hot water tank 30 is passed through the pump 34 and piping 35 to the heat source fluid flow path 4a of the heat exchanger 4, and heats it by exchanging heat with the raw water. The water whose temperature has been lowered by heat exchange with the raw water is returned to the hot water tank 30 via the piping 36.

Water in a cold water tank 40 is passed through a heat transfer tube 21a provided in an evaporator 21 via a pump 41 and a pipe 42, and is cooled by exchanging heat with a low-temperature heat medium. The water that has been cooled to become low-temperature water is returned to the cold water tank 40 via piping 43.

The low-temperature water in the tank 40 is passed through the pump 44 and piping 45 to the heat source fluid flow path 7a of the heat exchanger 7, and exchanges heat with the steam to cool it. The water whose temperature has increased by exchanging heat with the steam is returned to the cold water tank 40 via piping 46. This cold water tank 40 is provided with a heater 47.

Japanese Patent Application Publication No. 3-52627 JP 2019-158173 Publication

In a distillation apparatus that uses a heat pump for distillation operation as shown in FIG. 2, the thermal energy of the steam recovered by the heat exchanger 7 is used to heat the raw water by the heat pump 20, so that the thermal efficiency is improved. is good.

However, when starting the device when steam cannot be obtained from the distiller 1 or when the amount of steam is insufficient, the water in the cold water tank 40 loses heat unilaterally and eventually becomes supercooled. Heat pump system 12 stops.

In order to prevent such overcooling, it is common to install a heating device such as a heater 47 in the cold water tank 40.

An object of the present invention is to provide a distillation apparatus that can be stably operated by a heat pump alone without using a heat source such as a heater.

The gist of the present invention is as follows.

[1] A raw water circulation line that circulates the raw water in the distiller, a first heat exchanger provided in the raw water circulation line for heating the raw water, and a suction line that sucks steam from the distiller. a second heat exchanger provided in the suction line for cooling the steam; and a hot water circulation line that includes a hot water tank and circulates hot water in the hot water tank to the first heat exchanger. a cold water circulation line having a cold water tank, which circulates the cold water in the cold water tank to the second heat exchanger; and a cold water circulation line that circulates the cold water in the cold water tank to the second heat exchanger; A distillation apparatus having a heat pump that transfers heat from the low-temperature fluid to the high-temperature fluid; A distillation apparatus comprising a return line that causes cold water in a cold water tank to flow into the hot water tank.

[2] The distillation apparatus according to [1], wherein the return line causes overflow water that overflows from the cold water tank to flow into the hot water tank when hot water flows into the cold water tank from the introduction line.

[3] The distillation apparatus according to [1] or [2], wherein the introduction line is provided with a valve.

[4] The device according to [3], characterized by comprising a temperature sensor that detects the temperature of the cold water tank, and a controller that opens the valve when the temperature detected by the temperature sensor is lower than a set temperature. Distillation equipment.

[5] A pump and an outgoing pipe that send high-temperature water in the hot water tank to an inflow part of a condenser of the heat pump, and a return pipe that returns high-temperature water flowing out from an outflow part of the condenser to the hot water tank. The distillation apparatus according to [3] or [4], wherein the introduction line is an introduction pipe branching from the return pipe, and the introduction pipe is provided with the valve.

Generally, heat pumps have a gap in cooling capacity and heating capacity, with the heating capacity being greater. The present invention utilizes this gap to stably operate a distillation apparatus using a heat pump alone without using a heat source such as a heater.

The distillation apparatus of one embodiment of the present invention has a means for mixing hot water and cold water, and by controlling the mixing by the temperature of the cold water, it is possible to stably operate the heat pump without using a heat source such as a heater. It becomes possible.

FIG. 1 is a configuration diagram of a distillation apparatus according to an embodiment. It is a block diagram of the distillation apparatus based on a conventional example. It is a graph showing the results of a comparative example. It is a graph showing the results of a comparative example. It is a graph showing the results of a comparative example. It is a graph showing the results of Examples.

An embodiment will be described below with reference to FIG.

In this embodiment, a pipe 50 branches from the pipe 33. A portion of the high temperature water in the pipe 33 can be sent to the cold water tank 40 via the pipe 50, a valve 51, and a pipe 52.

Further, a temperature sensor 53 is provided in the cold water tank 40, and a detected temperature signal is input to a controller 54. The opening/closing or opening degree of the valve 51 is controlled by the controller 54 .

Further, a pipe 55 is provided to guide overflow water from the cold water tank 40 to the hot water tank 30.

The rest of the structure of the distillation apparatus in FIG. 1 is the same as in FIG. 2, and the same reference numerals indicate the same parts.

In this distillation apparatus, when the temperature of the water in the cold water tank 40 detected by the temperature sensor 53 is higher than the predetermined temperature T1, the valve 51 is closed, and the operation of the distillation apparatus in this state is as shown in FIG. This is the same as in the case of .

When the temperature of the water in the cold water tank 40 detected by the temperature sensor 53 is below a predetermined temperature T1 (for example, 30° C.), the valve 51 is opened.

As a result, a portion of the high-temperature water heated by the heat pump 20 is diverted from the pipe 33 and flows into the cold water tank 40 via the pipes 50 and 52. With this inflow of high temperature water, a portion of the water in the cold water tank 40 overflows into the pipe 55 and flows into the tank 30 via the pipe 55.

In this way, a portion of the high temperature water from the heat pump 20 flows into the cold water tank 40 and increases the water temperature in the cold water tank 40, thereby preventing overcooling.

The controller 54 closes the valve 41 when the temperature detected by the temperature sensor 53 exceeds a predetermined temperature T2 (for example, 40° C.).

This stops hot water from flowing into the cold water tank 40 from the hot water tank 30. After this, the entire amount of high-temperature water from the heat pump 20 flows into the hot water tank 30, so the rate of increase in the water temperature in the hot water tank 30 increases.

When the temperature of the water in the tank 30 reaches the target temperature T3 (for example, 80° C.), it becomes possible to generate steam in the distiller 1, and the distiller 1 shifts to steady operation.

Note that when the valve 51 is open, part of the thermal energy given to the water in the condenser 23 is given to the water in the tank 40 in the form of high-temperature water, but even in this case, the water temperature in the tank 30 is does not decrease. That is, in a heat pump, the heating capacity is generally greater than the cooling capacity, so a portion of the high temperature water is sent from the pipes 50 and 52 to the cold water tank 40, and the same amount of low temperature water is sent from the cold water tank 40 to the hot water tank. Even when the water is flowing into the hot water tank 30, the temperature of the water in the hot water tank 30 does not decrease, but gradually increases.

Hereinafter, an example of operation of the heat pump system 12 (composed of a heat pump 20, a hot water tank 30, a cold water tank 40, piping 50, 52, and a valve 51) used in the distillation apparatus of FIG. 1 will be described.

<Heat pump>
Heating capacity: 32.3kW
Cooling capacity: 19.8kW
Power consumption: 10kW
When the temperature of the cold water tank drops below 5℃, the system will shut down to prevent overcooling.

The target temperature of the hot water tank is 80°C.

<Tank capacity>
Both hot water tank and cold water tank are 100L.

[Comparative Example 1] (Valve 51 closed)
The valve 51 was closed and the operation of the heat pump system 12 was started with an initial temperature of hot water of 10°C and an initial temperature of cold water of 10°C.

Figure 3 shows the changes in temperature of hot water and cold water over time. This test assumes that city water in winter is recycled water. As shown in Figure 3, the temperature of the cold water tank reached 5°C in about 1.7 minutes and the heat pump stopped. At that time, the temperature reached by the hot water tank was approximately 18°C, which did not reach the target. From this test, it was recognized that when the initial temperature was 10° C., heating from an external heat source such as a heater was necessary.

[Comparative example 2]
The test was conducted under the same conditions as Comparative Example 1 except that the initial temperature of hot water was 30°C and the initial temperature of cold water was 30°C.

Figure 4 shows changes in the temperature of hot water and cold water over time. This test assumes that summer city water is circulating water. As shown in Figure 4, the temperature of the cold water tank reached 5°C in about 9 minutes and the heat pump stopped. At that time, the temperature reached by the hot water tank was approximately 70°C, which did not reach the target. From this test, it was recognized that even when the initial temperature was 30° C., heating from an external heat source such as a heater was necessary.

[Comparative example 3]
In Comparative Example 1, the test was conducted under the same conditions except that a 20 kW electric heater was installed and operated in the cold water tank.

Figure 5 shows changes in the temperature of hot water and cold water over time. In this test, since a heater with the same cooling capacity was used, the temperature of the cold water was constant at 10°C. The hot water reached 80° C. in about 15 minutes because the equipment did not stop due to supercooling. The total power consumption at this time was 7.6 kW.

[Example 1]
The operation of the heat pump system 12 was started at an initial temperature of hot water of 10°C and an initial temperature of cold water of 10°C.

The valve 51 was opened for 30 minutes from the start of operation, and the valve 51 was closed after 30 minutes.

Figure 6 shows changes in the temperature of hot water and cold water over time. Since the valve 51 is open for 30 minutes after the start of the test, the cold water and hot water are mixed and the temperature of both is rising. After that, the valve 51 is closed and mixing of hot water and cold water does not occur, so the hot water is heated and the cold water is cooled. Nine minutes after closing the valve 51, the hot water tank reached the target temperature of 80°C, and the cold water was cooled to the initial temperature of 10°C.

From the above, it has been confirmed that by applying the present invention, it is possible to start a heat pump without using a heat source such as a heater.

Moreover, the power consumption at this time is 6.6 kW. Compared to the case where the heater of Comparative Example 3 is used, the power consumption is about 13% lower. Therefore, it has been recognized that by using the present invention, it is also possible to reduce power consumption.

1 distiller 4,7 heat exchanger 12 heat pump system 20 heat pump 21 evaporator 22 compressor 23 condenser 24 expansion valve 30 hot water tank 40 cold water tank 47 heater 51 valve 53 temperature sensor 54 controller

Claims (5)

A raw water circulation line that circulates the raw water in the distiller,
a first heat exchanger for heating the raw water provided in the raw water circulation line;
a suction line for sucking vapor from the still;
a second heat exchanger provided in the suction line for cooling the steam;
a hot water circulation line having a hot water tank and circulating hot water in the hot water tank to the first heat exchanger;
a cold water circulation line having a cold water tank and circulating cold water in the cold water tank to the second heat exchanger;
A distillation apparatus having cold water in the cold water tank as a low temperature fluid, hot water in the hot water tank as a high temperature fluid, and a heat pump that transfers heat of the low temperature fluid to the high temperature fluid,
an introduction line that introduces a portion of the high-temperature water sent from the heat pump to the hot water tank into the cold water tank;
A distillation apparatus comprising: a return line for causing cold water in the cold water tank to flow into the hot water tank. 2. The distillation apparatus according to claim 1, wherein the return line causes overflow water that overflows from the cold water tank to flow into the hot water tank when hot water flows into the cold water tank from the introduction line. The distillation apparatus according to claim 1 or 2, wherein the introduction line is provided with a valve. a temperature sensor that detects the temperature of the cold water tank;
4. The distillation apparatus according to claim 3, further comprising a controller that opens the valve when the temperature detected by the temperature sensor is lower than a set temperature. a pump and an outgoing pipe that send high-temperature water in the hot water tank to an inlet of a condenser of the heat pump;
and a return pipe for returning high-temperature water flowing out from the outlet of the condenser to the hot water tank,
The introduction line is an introduction pipe that branches from the return pipe,
The distillation apparatus according to claim 3 or 4, wherein the introduction pipe is provided with the valve.

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