JP6777236B2 - Reverse osmosis treatment method and system - Google Patents

Description

The present invention relates to a reverse osmosis treatment method and system for treating water using a reverse osmosis membrane device, and more particularly to a reverse osmosis treatment method and system for heating water supply to the reverse osmosis membrane device with a heat pump.

In the reverse osmosis membrane device (hereinafter, may be referred to as RO device), the water supply temperature is set in order to maintain the amount of treated water (maintain flux by preventing decrease in water viscosity and improve recovery rate by increasing silica saturation solubility). It is heated to about 25 ° C. Steam, hot water, electric heaters, etc. are used to heat this water supply, which consumes energy.

Claim 7 of Japanese Patent Application Laid-Open No. 2012-91118 describes that the water supply of the RO apparatus is heated to 23 to 25 ° C. by a heat pump, but the Japanese Patent Application Laid-Open No. 2012 describes a specific description of the heat source of the heat pump. Not done.

JP 2012-91118

An object of the present invention is to reduce heating costs in a reverse osmosis treatment method and system for heating water supply to an RO apparatus with a heat pump.

The reverse osmosis treatment method of the present invention is a reverse osmosis treatment method in which raw water is heated by a heat pump and then membrane separation treatment is performed by a reverse osmosis membrane device. It is characterized by using.

In the reverse osmosis treatment system of the present invention, in a reverse osmosis treatment apparatus in which raw water is heated by a heat pump and then membrane separation treatment is performed by the reverse osmosis membrane apparatus, a hot medium flowing out from a heat exchanger of a refrigeration system as a heat source fluid of the heat pump. It is characterized by using.

In one aspect of the present invention, the raw water heated by the heat pump is heated by the second heat exchanger and then supplied to the reverse osmosis apparatus.

In one aspect of the present invention, steam from the boiler is supplied to the second heat exchanger as a heat source fluid for heating raw water.

In one aspect of the present invention, at least a part of the raw water heated by the heat pump is sent to the boiler as boiler supply water.

In one aspect of the present invention, a water supply tank in which water is circulated with the heat transfer tube of the condenser of the heat pump is installed, raw water is supplied to the water supply tank, and between the heat transfer tube and the water supply tank. The raw water is circulated and heated, and the heated raw water is supplied from the water supply tank to the reverse osmosis apparatus.

In one aspect of the present invention, a water supply tank in which water is circulated with the heat transfer tube of the condenser of the heat pump is installed, raw water is supplied to the water supply tank, and between the heat transfer tube and the water supply tank. The raw water is circulated and heated, and at least a part of the heated raw water is sent to the boiler as boiler supply water.

In one aspect of the present invention, the refrigerating system includes a refrigerator main body and a heat exchanger into which a refrigerant body from the refrigerator main body is introduced and a hot medium flows out, and flows out from the heat exchanger. A part of the warm medium is returned to the main body of the refrigerator, the rest is introduced into the evaporator of the heat pump, and the medium cooled by the evaporator is returned to the refrigerant body inflow side of the heat exchanger.

In one aspect of the present invention, the refrigerating system includes a refrigerator main body and a heat exchanger into which a refrigerant body from the refrigerator main body is introduced and a hot medium flows out, and flows out from the heat exchanger. A part of the warm medium is returned to the refrigerator body, the rest is introduced into the evaporator of the heat pump, and the medium cooled by the evaporator is returned to the refrigerator body.

According to the present invention, the heating cost of the water supply can be reduced by heating the water supply to the RO apparatus with a heat pump using a heat medium flowing out from the heat exchanger of the refrigeration system as a heat source.

In one aspect of the present invention, the temperature of the hot medium flowing out of the heat exchanger of the refrigerating system is lowered by the evaporator of the heat pump, so that the refrigerating load of the refrigerating machine can be reduced. As a result, the power consumption of the refrigerator body can be reduced, and the total benefit generated by the installation of the heat pump can be increased.

It is a block diagram of the reverse osmosis treatment system which concerns on 1st Embodiment. It is a block diagram of the reverse osmosis treatment system which concerns on 2nd Embodiment. It is a block diagram of the reverse osmosis treatment system which concerns on 3rd Embodiment. It is a block diagram of the reverse osmosis treatment system which concerns on 4th Embodiment. It is a block diagram of the reverse osmosis treatment system which concerns on 5th Embodiment.

The first embodiment will be described with reference to FIG.

The raw water to be RO-treated is supplied from the pipe 1 to the condenser 13 of the heat pump 10 by the pump 2, and after being heated, passes through the heat exchanger (second heat exchanger) 4 using steam as a heat source from the pipe 3. It is supplied to the RO device 6 via the pipe 5. The permeated water of the RO device 6 is taken out from the pipe 7 as treated water, and the concentrated water flows out to the pipe 8.

The type of boiler for supplying steam to the heat exchanger 4 is not particularly limited, and may be any of a small once-through boiler, a water pipe boiler, a round boiler, an exhaust heat boiler, and the like. Although heating by steam is not required during normal operation, it is used for heating when the refrigerator main body 21 described later is stopped or when the RO device 6 is started. However, if necessary, the RO water supply may be heated by the heat exchanger 4 even during normal operation.

The heat pump 10 has a well-known configuration, and a heat medium such as CFC substitutes from the evaporator 11 is introduced into the condenser 13 at a high temperature by adiabatic compression by the compressor 12, and the heat medium from the condenser 13 is introduced into the expansion valve 14. It is configured to be introduced into the evaporator 11 via an adiabatic expansion to lower the temperature. Raw water is passed through a heat transfer tube 13a provided in the condenser 13 via a pump 2, and is heated by exchanging heat with a high-temperature heat medium.

A part of the heat medium flowing out of the heat exchanger 24 of the refrigeration system 20 is introduced into the heat transfer tube 11a provided in the evaporator 11 via the pipe 31 and the valve 32. The refrigerant body whose temperature has been lowered by heat exchange with the low temperature heat medium in the evaporator 11 is introduced again into the heat exchanger 24 via the pipe 33.

The refrigerating system 20 heats a refrigerant body cooled by the refrigerator main body 21 such as a turbo refrigerator or an absorption chiller from a medium delivery unit 21a of the refrigerator main body 21 via a pipe 22 to a heat exchanger such as an air conditioner. It is supplied to (first heat exchanger) 24 to absorb ambient heat and cool the ambient. A part of the warm medium that has been heated by absorbing the ambient heat in the heat exchanger 24 is transferred from the heat exchanger 24 through the medium circulation pump 25, the pipe 26, and the valve 27 to the medium return portion 21b of the refrigerator main body 21. Return to.

The rest of the heat medium flowing out of the heat exchanger 24 is circulated to the heat transfer tube 11a of the evaporator 11 via the pipe 31 and the valve 32 branched from the pipe 26, exchanges heat with the heat pump heat medium, lowers the temperature, and cools. It becomes a medium and flows out to the pipe 33. The pipe 33 is connected to the pipe 22, and the refrigerant body from the pipe 33 merges with the refrigerant body from the refrigerator main body 21 and flows into the heat exchanger 24.

As described above, in this embodiment, the hot medium flowing out from the heat exchanger 24 is used as the heat source fluid flowing through the heat transfer tube 11a of the evaporator 11 of the heat pump 10. Further, the cooled refrigerant body is returned to the heat exchanger 24 by passing through the heat transfer tube 11a of the evaporator 11 of the heat pump 10.

The refrigerator main body 21 of the refrigerating system 20 uses cold water from the cooling tower 40 as a low-temperature fluid for cooling.

In the cooling tower 40, the cooling water sprinkled from the sprinkler pipe 41 comes into contact with the air introduced from the louver 43 while flowing down the filler layer 42, and is cooled by the latent heat of evaporation to become cold water, and becomes pit 44 (cooling tower). It is stored in the lower water tank). The air containing steam is exhausted into the atmosphere by the fan 48. The cold water in the pit 44 is supplied to the refrigerator main body 21 via the pump 45 and the pipe 46, and heats are exchanged to raise the temperature. The warming water from the refrigerator main body 21 is returned to the sprinkler pipe 41 via the pipe 47.

In the reverse osmosis treatment apparatus of FIG. 1 configured in this way, the raw water is heated by the heat pump 10 and then heated by the heat exchanger 4 as needed and supplied to the RO apparatus 6.

In this embodiment, as the heat source of the heat pump 10, a hot medium flowing out from the heat exchanger 24 such as an air conditioner installed in the refrigerating system 20 is used, and the refrigerating load of the refrigerating machine main body 21 can be reduced. it can. Further, since the power consumption of the refrigerator main body 21 can be reduced by this, the power consumption of the heat pump 10 is substantially offset. Therefore, the reduction amount of steam for heating can be recorded as a benefit as it is, so that the investment can be quickly recovered by installing the heat pump.

A second embodiment will be described with reference to FIG.

In the refrigeration system 20 of FIG. 1, the refrigerant body sent from the refrigerator main body 21 via the pipe 22 and the refrigerant body sent from the evaporator 11 via the pipe 33 are merged to form an air conditioner or the like. Although it flows into the heat exchanger 24, in the embodiment of FIG. 2, only the refrigerant body sent from the medium delivery portion 21a of the refrigerator main body 21 via the pipe 22 flows into the heat exchanger 24.

The warm medium flowing out of the heat exchanger 24 is sent out to the pipe 28 by the medium circulation pump 25. A part of the sent hot medium is circulated to the medium return portion 21b of the refrigerator main body 21 via the valve 29 and the pipe 30.

The rest of the hot medium sent out to the pipe 28 is circulated to the heat transfer tube 11a of the evaporator 11 via the pipe 35 and the valve 36 branched from the pipe 28, exchanges heat with the heat pump heat medium, and lowers the temperature to lower the refrigerant body. Then, the pipe 37 joins the pipe 30 and returns to the medium return portion 21b of the refrigerating machine main body 21.

The other configurations of FIG. 2 are the same as those of FIG. 1, and the same reference numerals indicate the same parts.

Also in this embodiment, as in the embodiment of FIG. 1, as the heat source of the heat pump 10, a warm medium flowing out from the heat exchanger 24 such as an air conditioner installed in the refrigeration system 20 is used for freezing. The refrigerating load of the machine body 21 can be reduced.

In addition, according to the system of FIG. 1, raw water (20 ° C.) was heated to 25 ° C. and RO-treated at 100 m ³ / h, and a turbo refrigerator (500RT) was operated as a refrigerator main body 21 at COP (performance coefficient) 5. The medium of the refrigerator main body 21 is water, the inflow water (warm medium) temperature of the refrigerator main body return portion 21b is 12 ° C., and the outflow water (refrigerator body) temperature of the refrigerator main body delivery portion 21a is 7 ° C. When the heat pump (470 kW) is operated at COP (performance coefficient) 6 without supplying steam, the raw water is heated from 20 ° C. to 25 ° C. only by the steam heat exchanger 4, and steam is sent to the steam heat exchanger 4. It is estimated that the energy cost will be 80% or less as compared with the case of supplying the above with three small once-through boilers (converted evaporation amount 2000 kg / h, fuel LNG, steam pressure 0.7 MPa).

Further, it is estimated that the energy cost of the system of FIG. 1 is 90% or less as compared with the case where the raw water is heated from 20 ° C. to 25 ° C. only by a heat pump.

A third embodiment will be described with reference to FIG.

In FIG. 1, the total amount of raw water heated through the heat transfer tube 13a of the condenser 13 of the heat pump 10 is sent from the pipe 3 to the heat exchanger 4, and is used as a heat source fluid for the heat exchanger 4. Steam is supplied from the boiler. In FIG. 3, the pipe 3 is branched into two systems of pipes 50 and 60.

The heated raw water flowing through the pipe 50 is sent to the heat exchanger 4 via the valve 51, the water supply tank 52, and the pipe 53. Further, a pipe 86 provided with a valve 85 is connected to the water supply tank 52 in order to supply the raw water that is not heated by the heat pump 10 (hereinafter, may be referred to as “unheated raw water”) to the water supply tank 52.

The heated raw water flowing through the pipe 60 is sent to the water supply tank 64 via the valve 61, the first water softener 62, and the pipe 63. Boiler water that has passed through the second water softener 65 is also introduced into the water supply tank 64 via the pipe 66. The water softeners 62 and 65 have a container and an ion exchange resin filled in the container, and use raw water or boiler water as soft water. The boiler water may be water from the same water source as the raw water, or may be water from another water source.

The water in the water supply tank 64 is supplied to the boiler 70 via the pipe 67. The steam generated in the boiler 70 is supplied to the heat exchanger 4 via the pipe 71. The raw water from the pipe 53 is heated by the heat exchanger 4 and supplied to the RO device 6. The condensed water generated by the condensation of steam in the heat exchanger 4 may be sent to the water supply tank 64.

The other configurations of FIG. 3 are the same as those of FIG. 1, and the same reference numerals indicate the same parts.

In FIG. 3, the heat exchanger 24, the refrigerator 20, and the cooling tower 40 connected to the heat pump 10 are configured as shown in FIG. 1, but may be configured as shown in FIG.

According to this third embodiment, not only the water supply to the RO device 6 but also a part of the water supply to the boiler 70 can be heated by one heat pump 10.

Further, the valve 51 and the valve 61 can switch the supply destination of the heated raw water and adjust the supply amount. Then, the raw water heated by the heat pump 10 is preferentially supplied to the RO device 6 by using the valve 51 and the valve 61, and the surplus of the heated raw water is supplied to the boiler 70, so that the raw water supplied to the RO device 6 is supplied. It is possible to effectively reduce the heating steam of the above and to effectively use the raw water heated by the heat pump 10.

For example, when the heated raw water is lower than the set temperature (for example, 25 ° C.) of the water supply of the RO device 6, the valves 51 and 61 are adjusted so that the entire amount of the supplied water of the RO device 6 is used as the heated raw water. When the total amount of the heated raw water exceeds the water supply amount of the RO device 6, the surplus of the heated raw water is sent to the water supply tank 64 and used as boiler water supply. When the heated raw water exceeds the set temperature of the water supply of the RO device 6 (for example, 25 ° C.) in summer or the like, the water supply of the RO device 6 can be set to the set temperature by adjusting the valve 51, the valve 61, and the valve 85. The supply amounts of the heated raw water and the unheated raw water supplied to the water supply tank 64 are adjusted so as to be the same, and the surplus of the heated raw water is sent to the water supply tank 64. By doing so, the raw water heated by the heat pump can be effectively used throughout the year.

The supply destination of the heated raw water may be switched depending on the temperature of the unheated raw water or the season. For example, when the temperature of the unheated raw water exceeds a predetermined temperature, or in the summer, the entire amount of the supplied water of the RO device 6 is used as the unheated raw water, and all the heated raw water is used as the boiler supply water. 85 may be adjusted. Further, when the temperature of the unheated raw water is below a predetermined temperature, or in a season other than summer, the entire amount of the supplied water of the RO device 6 is used as the heated raw water, and the surplus of the heated raw water is used as the boiler supply water. Valves 51, 61 and 85 may be adjusted.

A fourth embodiment will be described with reference to FIG.

In the system of FIG. 3, the raw water heated by the condenser 13 of the heat pump 10 is sent to the pipe 3 as it is, but in the system of FIG. 4, the raw water from the pipe 1 is introduced into the water supply tank 80 and the water supply tank 80 is used. The raw water in the water is sent to the heat transfer tube 13a of the condenser 13 via the pump 81 and the pipe 82. The heated raw water flowing out of the heat transfer tube 13a is returned to the water supply tank 80 via the pipe 83. In this way, the temperature of the raw water in the water supply tank 80 rises. The hot raw water in the water supply tank 80 is sent to the pipe 3 via the pump 84.

The other configurations of FIG. 4 are the same as those of FIG. 3, and the same reference numerals indicate the same parts. The system of FIG. 4 also has the same effect as the system of FIG. In FIG. 4, since the raw water is circulated between the water supply tank 80 and the condenser 13, the raw water heated to a temperature higher than that in the case of FIG. 3 can be sent out to the pipe 3.

In FIG. 4, the heat exchanger 24, the refrigerator 20, and the cooling tower 40 connected to the heat pump 10 are configured as shown in FIG. 1, but may be configured as shown in FIG.

Table 1 shows the results of trial calculation of the steam cost when the device of FIG. 3 is assumed and operated under the following conditions.

<Operating conditions>
Boiler: once-through boiler, equivalent evaporation amount 6000 kg / h x 10 units, fuel LNG, steam pressure 0.7 MPa
RO device: Raw water supply 100m ³ / h
Heat pump: 470 kW, COP (coefficient of performance) 6
The amount of steam used other than the heating of RO water supply: 240,000t / year Average heating temperature of raw water with a heat pump: 5 ° C
LNG unit price: 50 yen / Nm ³ = steam unit price 3963 yen / t, assuming that steam fuel is reduced by 0.8% (steam unit price 3931 yen) by heat recovery at 5 ° C.

[Test Example 1]
The entire amount of raw water heated by the heat pump is used as boiler water supply, and RO water supply heats the raw water from 20 ° C to 25 ° C with steam (1,228t / year) from the boiler.

[Test Example 2]
In seasons other than summer, the entire amount of raw water heated by the heat pump is used as RO water supply. In the summer, the raw water is used at 25 ° C without heating. For the boiler water supply, raw water that was not completely heated was used.

[Test Example 3]
In the summer, the entire amount of raw water heated by the heat pump was used as boiler water supply, and in other seasons, the entire amount of raw water heated by the heat pump was used as RO water supply.

As shown in Table 1, by switching the supply destination of the heated raw water by the heat pump depending on the season, the steam for heating the raw water supplied to the RO device is effectively reduced, and the raw water heated by the heat pump is effectively used. By doing so, it became possible to suppress the steam cost.

A fifth embodiment will be described with reference to FIG.

In this embodiment, the water supply tank 80, the pump 81, the pipes 82, 83, and the pump 84 are installed in the system of FIG. As in the case of FIG. 4, raw water is circulated between the heat transfer tube 13a and the water supply tank 80 to heat it. The heated raw water is sent from the pump 84 to only the RO device 6 via the pipe 3.

According to this embodiment, raw water heated to a higher temperature than in the case of FIG. 1 is sent to the RO apparatus.

The above embodiment is an example of the present invention, and the present invention may be a form other than the illustration.

For example, although the steam heat exchanger 4 is used in FIGS. 1, 2 and 5, a heat exchanger using a heat source other than steam may be installed instead of the steam heat exchanger 4.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the intent and scope of the invention.

This application is based on Japanese Patent Application No. 2018-129257 filed on July 6, 2018, which is incorporated by reference in its entirety.

4 Steam heat exchanger 6 RO device 10 Heat pump 11 Evaporator 12 Compressor 13 Condenser 14 Expansion valve 20 Refrigeration system 21 Refrigerator body 24 Heat exchanger 40 Cooling tower 52, 64, 80 Water supply tank 70 Boiler

Claims (14)

In a reverse osmosis treatment method in which raw water is heated by a heat pump and then membrane separation is performed by a reverse osmosis membrane device.
As a heat source fluid of the heat pump, a reverse osmosis treatment method using the temperature medium flowing out of the refrigerator main body (21) and the first heat exchanger (24) the first heat exchanger of the refrigeration system with a (24) ,
A part of the warm medium flowing out of the heat exchanger (24) is returned to the refrigerator main body (21), the rest is introduced into the heat pump, and the medium cooled by the heat pump is returned to the heat exchanger (24). A reverse osmosis treatment method characterized by this. In a reverse osmosis treatment method in which raw water is heated by a heat pump and then membrane separation is performed by a reverse osmosis membrane device.
A reverse osmosis treatment method using a warm medium flowing out of the first heat exchanger (24) of a refrigeration system having a refrigerator main body (21) and a first heat exchanger (24) as the heat source fluid of the heat pump. ,
A part of the warm medium flowing out of the heat exchanger (24) is returned to the refrigerator main body (21), the rest is introduced into the heat pump, and the medium cooled by the heat pump is returned to the refrigerator main body (21). A reverse osmosis treatment method characterized by this. The reverse osmosis treatment method according to claim 1 or 2 , wherein the raw water heated by the heat pump is heated by the second heat exchanger (4) and then supplied to the reverse osmosis apparatus. The reverse osmosis treatment method according to claim 3 , wherein steam from a boiler is supplied to the second heat exchanger as a heat source fluid for heating raw water. The reverse osmosis treatment method according to claim 4 , wherein at least a part of the raw water heated by the heat pump is sent to the boiler as boiler supply water. A water supply tank in which water is circulated between the heat transfer tube of the condenser of the heat pump is installed, raw water is supplied to the water supply tank, and the raw water is circulated and heated between the heat transfer tube and the water supply tank. The reverse osmosis treatment method according to any one of claims 1 to 4 , wherein the heated raw water is supplied from the water supply tank to the reverse osmosis apparatus. A water supply tank in which water is circulated between the heat transfer tube of the condenser of the heat pump is installed, raw water is supplied to the water supply tank, and raw water is circulated and heated between the heat transfer tube and the water supply tank. The reverse osmosis treatment method according to claim 5 , wherein at least a part of the heated raw water is supplied to the boiler as boiler water supply. In a reverse osmosis treatment system in which raw water is heated by a heat pump and then membrane separation is performed by a reverse osmosis membrane device.
As a heat source fluid of the heat pump, a reverse osmosis treatment system using warm medium flowing out of the refrigerator main body (21) and the first heat exchanger (24) the first heat exchanger of the refrigeration system with a (24) ,
A part of the warm medium flowing out of the heat exchanger (24) is returned to the refrigerator main body (21), the rest is introduced into the heat pump, and the medium cooled by the heat pump is returned to the heat exchanger (24). A reverse osmosis treatment system characterized by this. In a reverse osmosis treatment system in which raw water is heated by a heat pump and then membrane separation is performed by a reverse osmosis membrane device.
A reverse osmosis treatment system using a warm medium flowing out of the first heat exchanger (24) of a refrigeration system having a refrigerator main body (21) and a first heat exchanger (24) as the heat source fluid of the heat pump. ,
A part of the warm medium flowing out of the heat exchanger (24) is returned to the refrigerator main body (21), the rest is introduced into the heat pump, and the medium cooled by the heat pump is returned to the refrigerator main body (21). A reverse osmosis treatment system characterized by this. The reverse osmosis treatment system according to claim 8 or 9, further comprising a second heat exchanger (4) that further heats the raw water heated by the heat pump and supplies it to the reverse osmosis apparatus. The reverse osmosis treatment system according to claim 10, wherein the second heat exchanger has a boiler that supplies steam as a heat source fluid for heating raw water. The reverse osmosis treatment system according to claim 11, further comprising means for supplying at least a part of the raw water heated by the heat pump to the boiler as boiler supply water. It has a water supply tank in which water is circulated between the heat transfer tube of the condenser of the heat pump, supplies raw water to the water supply tank, and circulates the raw water between the heat transfer tube and the water supply tank to heat the water. The reverse osmosis treatment system according to any one of claims 8 to 11, wherein the heated raw water is supplied from the water supply tank to the reverse osmosis apparatus. A water supply tank in which water is circulated between the heat transfer tube of the condenser of the heat pump is installed, raw water is supplied to the water supply tank, and raw water is circulated and heated between the heat transfer tube and the water supply tank. The reverse osmosis treatment system according to claim 12, wherein at least a part of the heated raw water is supplied to the boiler as boiler water supply.

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