WO2020008884A1

WO2020008884A1 - Reverse osmosis treatment method and system

Info

Publication number: WO2020008884A1
Application number: PCT/JP2019/024317
Authority: WO
Inventors: 孝司青木; 小野　雄壱
Original assignee: 栗田工業株式会社
Priority date: 2018-07-06
Filing date: 2019-06-19
Publication date: 2020-01-09
Also published as: TWI781329B; JPWO2020008884A1; JP6777236B2; CN112384479B; KR102477968B1; CN112384479A; TW202005706A; KR20210024463A

Abstract

Raw water is heated by a condenser 13 of a heat pump 10 and then supplied to an RO device 6 through a heat exchanger 4 using steam as a heat source. A part of a warm medium which flows out from a heat exchanger 24 of a refrigeration system 20 is circulated through a heat transfer tube 11a of an evaporator 11 of the heat pump 10. The medium whose temperature has dropped by passing through the heat transfer tube 11a is circulated and supplied to the heat exchanger 24. The refrigeration system 20 circulates a refrigerant from a refrigerator main body 21 through the heat exchanger 24 such as an air conditioner.

Description

Reverse osmosis treatment method and system

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

In the case of a reverse osmosis membrane device (hereinafter, sometimes referred to as an RO device), the feed water temperature is adjusted to maintain the treated water volume (maintaining the flux by preventing a decrease in the viscosity of water and improving the recovery rate by increasing the saturation solubility of silica). It is heated to about 25 ° C. Steam, hot water, electric heaters, and the like are used to heat the supply water, and energy is consumed.

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

JP 2012-91118 A

The present invention aims to reduce the heating cost in a reverse osmosis treatment method and system in which water supplied to an RO device is heated by 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 subjected to membrane separation treatment by a reverse osmosis membrane device, wherein a warm medium flowing out of a heat exchanger of a refrigeration system as a heat source fluid of the heat pump Is used.

The reverse osmosis treatment system of the present invention is a reverse osmosis treatment device in which raw water is heated by a heat pump and then subjected to membrane separation treatment by a reverse osmosis membrane device, wherein a warm medium flowing out of a heat exchanger of a refrigeration system as a heat source fluid of the heat pump. Is used.

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 device.

In one embodiment 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 embodiment of the present invention, at least a part of the raw water heated by the heat pump is supplied to the boiler as boiler feed water.

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

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

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

In one aspect of the present invention, the refrigeration system includes a refrigerator main body, and the heat exchanger into which a refrigerant from the refrigerator main body is introduced and a warm medium flows out. A part of the warming medium to be returned is returned to the refrigerator main body, the remaining part is introduced into the evaporator of the heat pump, and the medium whose temperature has been lowered by the evaporator is returned to the refrigerator main body.

According to the present invention, it is possible to reduce the heating cost of the feed water by heating the feed water to the RO device with a heat pump using the heat medium flowing out of the heat exchanger of the refrigeration system as a heat source.

In one embodiment of the present invention, the temperature of the warming medium flowing out of the heat exchanger of the refrigeration system is decreased by the evaporator of the heat pump, so that the refrigeration load of the refrigerator can be reduced. As a result, the power consumption of the refrigerator main body can be reduced, and the total benefit generated by installing the heat pump can be increased.

It is a block diagram of a reverse osmosis treatment system concerning a 1st embodiment. It is a block diagram of the reverse osmosis treatment system concerning a 2nd embodiment. It is a block diagram of a reverse osmosis treatment system concerning a 3rd embodiment. It is a block diagram of the reverse osmosis treatment system concerning a 4th embodiment. It is a block diagram of the reverse osmosis treatment system concerning a 5th embodiment.

(1) The first embodiment will be described with reference to FIG.

The raw water to be subjected to the RO treatment is supplied from a pipe 1 to a condenser 13 of a heat pump 10 by a pump 2, heated, and then passes through a heat exchanger (second heat exchanger) 4 using steam as a heat source from a 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 of the pipe 7 as treated water, and the concentrated water flows out of the pipe 8.

形式 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 tube boiler, a round boiler, and a waste heat boiler. It should be noted that during normal operation, heating by steam is not necessary, but it is used for heating, for example, when the refrigerator body 21 is stopped or when the RO device 6 is started, which will be described later. However, if necessary, the RO feedwater may be heated by the heat exchanger 4 even during normal operation.

The heat pump 10 has a well-known configuration, and introduces a heat medium, such as chlorofluorocarbon alternative, from the evaporator 11 to the condenser 13 at a high temperature by adiabatic compression in the compressor 12, and transfers the heat medium from the condenser 13 to the expansion valve 14. Is introduced into the evaporator 11 through the, and is adiabatically expanded to lower the temperature. Raw water is passed through the heat transfer tube 13 a provided in the condenser 13 via the pump 2, and exchanges heat with a high-temperature heat medium to be heated.

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

The refrigeration system 20 is configured to transfer a refrigerant cooled by a refrigerator main body 21 such as a turbo refrigerator or an absorption refrigerator to a heat exchanger such as an air conditioner via a pipe 22 from a medium delivery unit 21a of the refrigerator main body 21. (First heat exchanger) 24 to absorb the heat of the surroundings and cool the surroundings. A part of the warming medium, which has been heated by absorbing the surrounding heat in the heat exchanger 24, is transferred from the heat exchanger 24 via the medium circulation pump 25, the pipe 26, and the valve 27 to the medium return portion 21 b of the refrigerator body 21. Return to

The remaining portion of the warm medium flowing out of the heat exchanger 24 flows through the heat transfer tube 11a of the evaporator 11 via the pipe 31 branched from the pipe 26 and the valve 32, exchanges heat with the heat pump heat medium, and cools down by cooling. It becomes a medium and flows out to the pipe 33. The pipe 33 is connected to the pipe 22, and the refrigerant from the pipe 33 joins with the refrigerant from the refrigerator main body 21 and flows into the heat exchanger 24.

As described above, in this embodiment, the heating medium flowing out of 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. In addition, the refrigerant whose temperature has been lowered by passing through the heat transfer tube 11 a of the evaporator 11 of the heat pump 10 is returned to the heat exchanger 24.

The refrigerator main body 21 of the refrigeration 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 water sprinkling 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 the pit 44 (cooling tower) (Lower tank). Air containing steam is exhausted to the atmosphere by a fan 48. The cold water in the pit 44 is supplied to the refrigerator main body 21 via a pump 45 and a pipe 46, and exchanges heat to raise the temperature. The warm return water from the refrigerator main body 21 is returned to the sprinkling pipe 41 via the pipe 47.

In the reverse osmosis treatment device of FIG. 1 configured as described above, the raw water is heated by the heat pump 10, then, if necessary, is heated by the heat exchanger 4, and is supplied to the RO device 6.

In this embodiment, a heating medium flowing out of a heat exchanger 24 such as an air conditioner installed in the refrigeration system 20 is used as a heat source of the heat pump 10, and the refrigeration load of the refrigerator main body 21 can be reduced. it can. In addition, since the power consumption of the refrigerator main body 21 can be reduced, the power consumed by the heat pump 10 is almost offset. For this reason, since the amount of reduction of the steam for heating can be directly recorded as a benefit, the investment in the heat pump can be quickly recovered.

A second embodiment will be described with reference to FIG.

In the refrigeration system 20 of FIG. 1, the refrigerant sent from the refrigerator main body 21 via the pipe 22 and the refrigerant sent from the evaporator 11 via the pipe 33 are combined to form an air conditioner or the like. Although the refrigerant flows into the heat exchanger 24, in the embodiment of FIG. 2, only the refrigerant sent from the medium delivery portion 21 a 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 a pipe 28 by a medium circulation pump 25. A part of the sent warm medium is circulated to the medium return part 21b of the refrigerator main body 21 via the valve 29 and the pipe 30.

The remaining portion of the heating medium sent to the pipe 28 flows through 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 cools down by cooling. And merges with the pipe 30 from the pipe 37 and returns to the medium return portion 21b of the refrigerator main body 21.

2 The other configuration of FIG. 2 is the same as that of FIG. 1, and the same reference numerals indicate the same parts.

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

In addition, according to the system of FIG. 1, raw water (20 ° C.) is heated to 25 ° C., subjected to RO treatment at 100 m ³ / h, and a centrifugal chiller (500 RT) is operated as a refrigerator main body 21 at a COP (coefficient of performance) of 5, The medium of the refrigerator main body 21 is water, and the inflow water (warm medium) temperature of the refrigerator main body return portion 21b is 12 ° C., and the outflow water (refrigerant) temperature of the refrigerator main body delivery portion 21a is 7 ° C. When a heat pump (470 kW) is operated with a COP (coefficient of performance) 6 without supplying steam, the raw water is heated from 20 ° C. to 25 ° C. by the steam heat exchanger 4 alone, and the steam is supplied 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 with three small once-through boilers (equivalent evaporation 2000 kg / h, fuel LNG, steam pressure 0.7 MPa).

The energy cost of the system in Fig. 1 was estimated to be 90% or less compared to the case where raw water is heated from 20 ° C to 25 ° C using only a heat pump.

A third embodiment will be described with reference to FIG.

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

pipes

50 and 60.

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

加熱 The heated raw water flowing into the pipe 60 is sent to the water supply tank 64 via the valve 61, the first water softener 62 and the pipe 63. The boiler water that has passed through the second water softener 65 is also introduced into the water supply tank 64 via the pipe 66. Each of the

water softeners

62 and 65 has a container and an ion-exchange resin filled in the container, and uses 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.

水 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. 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 the steam in the heat exchanger 4 may be sent to the water supply tank 64.

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

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

According to the 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.

供給 Further, the supply destination of the heating raw water can be switched or the supply amount can be adjusted by the valve 51 and the valve 61. Then, the raw water supplied by the heat pump 10 is preferentially supplied to the RO device 6 using the valve 51 and the valve 61, and the surplus of the heated raw water is supplied to the boiler 70, whereby the raw water supplied to the RO device 6 is supplied. It is possible to effectively reduce the amount of steam for heating, and to effectively use the raw water heated by the heat pump 10.

For example, when the raw water to be heated is lower than the set temperature (for example, 25 ° C.) of the water supplied to the RO device 6, the

valves

51 and 61 are adjusted so that the entire amount of the supplied water to the RO device 6 is used as the raw water to be heated. When the total amount of the heating raw water exceeds the amount of water supplied to the RO device 6, the surplus heating water is sent to the water supply tank 64 and used as boiler water. When the raw water to be heated exceeds the set temperature (for example, 25 ° C.) of the feed water of the RO device 6 in summer or the like, the valve 51, the valve 61, and the valve 85 are adjusted to adjust the feed water of the RO device 6 to the set temperature. In addition to adjusting the supply amounts of the heated raw water and the non-heated raw water supplied to the water supply tank 64 so as to satisfy the condition, the surplus amount of the heated raw water is supplied to the water supply tank 64. In this way, the raw water heated by the heat pump can be effectively used throughout the year.

Note that the supply destination of the heating raw water may be switched depending on the temperature of the non-heating raw water or the season. For example, when the temperature of the non-heated raw water exceeds a predetermined temperature, or in summer, the entire amount of the supply water of the RO device 6 is the non-heated raw water, and the

valves

51, 61 and 85 may be adjusted. Further, when the temperature of the non-heated raw water is equal to or lower than a predetermined temperature, or in a season other than summer, the entire amount of the supply water of the RO device 6 is used as the raw water for heating, and the surplus of the raw water for heating is used as the boiler water supply. The

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 directly sent to the pipe 3, but in the system of FIG. 4, the raw water from the pipe 1 is introduced into the water supply tank 80, The internal raw water is sent to the heat transfer tube 13 a 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. Thus, the temperature of the raw water in the water supply tank 80 increases. The high temperature raw water in the water supply tank 80 is sent to the pipe 3 via the pump 84.

4 The other configurations in FIG. 4 are the same as those in FIG. 3, and the same reference numerals indicate the same parts. The same effects as those of the system of FIG. 3 can be obtained by the system of FIG. In FIG. 4, the raw water is circulated through the water supply tank 80 and the condenser 13, so that the raw water heated to a higher temperature than in the case of FIG.

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

Table 1 shows the results of a trial calculation of the steam cost when the apparatus shown in Fig. 3 was operated under the following conditions.

<Operating conditions>
Boiler: once-through boiler, reduced evaporation 6000 kg / h × 10 units, fuel LNG, steam pressure 0.7 MPa
RO device: raw water supply amount 100m ³ / h
Heat pump: 470 kW, COP (coefficient of performance) 6
Steam consumption other than RO feed water heating: 240,000 t / year Average heating temperature of raw water by 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 feed water, and RO feed water is heated from 20 ° C. to 25 ° C. by steam (1,228 t / year) from the boiler.

[Test Example 2]
In the seasons other than summer, the entire amount of raw water heated by the heat pump is used as RO water supply. In summer, raw water is used without heating, assuming that the temperature is 25 ° C. For boiler feed water, raw water was used without heating the whole amount.

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

As shown in Table 1, by switching the supply destination of heated raw water by the heat pump according to 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 used effectively. By doing so, it became possible to suppress the steam cost.

(5) A fifth embodiment will be described with reference to FIG.

In this embodiment, the water supply tank 80, the pump 81, the

pipes

82 and 83, and the pump 84 are installed in the system of FIG. As in the case of FIG. 4, the raw water is heated by circulating between the heat transfer tube 13a and the water supply tank 80. 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 device.

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

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

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

Reference Signs List 4 steam heat exchanger 6 RO device 10 heat pump 11 evaporator 12 compressor 13 condenser 14 expansion valve 20 refrigeration system 21 refrigerator main body 24 heat exchanger 40

cooling tower

52, 64, 80 water supply tank 70 boiler

Claims

In a reverse osmosis treatment method in which raw water is heated by a heat pump and then subjected to a membrane separation treatment in a reverse osmosis membrane device,
A reverse osmosis treatment method comprising using a heating medium flowing out of a heat exchanger of a refrigeration system as a heat source fluid of the heat pump.
The reverse osmosis treatment method according to claim 1, wherein the raw water heated by the heat pump is supplied to the reverse osmosis device after being heated by the second heat exchanger.
3. The reverse osmosis treatment method according to claim 2, wherein steam from the 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 3, wherein at least a part of the raw water heated by the heat pump is supplied to the boiler as boiler feedwater.
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. 4. The reverse osmosis treatment method according to claim 1, wherein heated raw water is supplied from the water supply tank to the reverse osmosis device.
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 claim 4, wherein at least a part of the heated raw water is supplied to the boiler as boiler feedwater.
The refrigeration system includes a refrigerator main body, the heat exchanger into which a refrigerant from the refrigerator main body is introduced, and a heating medium flows out,
A part of the warm medium flowing out of the heat exchanger is returned to the refrigerator main body, and the remaining part is introduced into the evaporator of the heat pump, and the medium cooled by the evaporator is returned to the refrigerant inlet side of the heat exchanger. The reverse osmosis treatment method according to any one of claims 1 to 6, wherein:
The refrigeration system includes a refrigerator main body, the heat exchanger into which a refrigerant from the refrigerator main body is introduced, and a heating medium flows out,
A part of the warm medium flowing out of the heat exchanger is returned to the refrigerator main body, the remaining part is introduced into an evaporator of the heat pump, and the medium cooled by the evaporator is returned to the refrigerator main body. The reverse osmosis treatment method according to any one of claims 1 to 6.
In a reverse osmosis treatment system where raw water is heated by a heat pump and then subjected to membrane separation by a reverse osmosis membrane device,
A reverse osmosis treatment system, wherein a heating medium flowing out of a heat exchanger of a refrigeration system is used as a heat source fluid of the heat pump.
10. The reverse osmosis treatment system according to claim 9, further comprising a second heat exchanger that further heats the raw water heated by the heat pump and supplies the raw water to the reverse osmosis device.
11. The reverse osmosis treatment system according to claim 10, further comprising a boiler that supplies steam to the second heat exchanger as a heat source fluid for heating raw water.
12. The reverse osmosis treatment system according to claim 11, further comprising means for feeding at least a part of the raw water heated by the heat pump to the boiler as boiler feed water.
The water pump has a water supply tank through which water is circulated between a heat transfer tube of a 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 raw water. The reverse osmosis treatment system according to any one of claims 9 to 11, wherein heated raw water is supplied from the water supply tank to the reverse osmosis device.
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 system according to claim 12, wherein at least a part of the heated raw water is supplied to the boiler as boiler feedwater.