JP2021120988A - Control method of heating means of thermal pure water supply device - Google Patents

Abstract

To provide a control method of heating means of a thermal pure water supply device, capable of improving an energy efficiency by appropriately controlling the heating means.SOLUTION: Time series data of a utilization situation of a facility such as a washing machine of a use point 2 and a use amount of a thermal ultra-pure water W3 is acquired in advance. Then, time series prediction data of the use amount of a future thermal ultra-pure water W3 is created from a future utilization situation (demand) of the facility such as the washing machine of the use point 2 on the basis of above. The number of operations of a heat pump, which is appropriate in the point of a heating COP of the heat pump and the number of starting/stopping frequencies is determined from the time series prediction data of the use amount of this thermal ultra-pure water W3, and is controlled. The number of heat pumps, of which the heating COP of the heat pump becomes a predetermined value or more is set from the use amount of the thermal ultra-pure water W3 by the number of operations.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for controlling a heating means of a warm pure water supply device, and more particularly to a method for controlling a heating means of a hot pure water supply device capable of improving energy efficiency by appropriately controlling the number of operating units of a plurality of heating means.

The ultrapure water used as water for cleaning semiconductors is, for example, ultrapure water composed of a pretreatment system 50, a primary pure water production device 60, and a secondary pure water production device (subsystem) 70 as shown in FIG. It is produced by treating raw water (industrial water, city water, well water, etc.) W with a water production device.

In the pretreatment system 50 including agglomeration, pressure flotation (precipitation), filtration (membrane filtration) and the like (coagulation filtration device in this conventional example), suspended solids and colloidal substances in the raw water W are removed. Further, in this process, it is possible to remove high molecular weight organic substances and hydrophobic organic substances.

A primary equipped with a pretreated water tank 61, a heat exchanger 62, a reverse osmosis membrane treatment device (RO device) 63, an ion exchange device (mixed bed type or 4-bed 5-tower type, etc.) 64, and a degassing device 65. The pure water production apparatus 60 removes ions and organic components in the raw water. Steam is supplied to the primary side of the heat exchanger 62 as a heat source fluid. The reverse osmosis membrane treatment apparatus 63 removes salts and also removes ionic and colloidal TOCs. The ion exchange device 64 removes salts and inorganic carbon (IC), and also removes TOC components that are adsorbed or ion-exchanged by the ion exchange resin. The degassing device 65 removes inorganic carbon (IC) and dissolved oxygen.

The primary pure water W1 produced by the primary pure water production apparatus 60 is sent to the secondary pure water production apparatus 70 via the pipe 66. The secondary pure water production device 70 includes a sub tank 71, a pump 72, a heat exchanger 73, a degassing membrane 74, a low pressure ultraviolet oxidizing device (UV device) 75, a water supply pump 76, a non-regenerative ion exchange device 77, and an ultrafiltration device. The filtration membrane (UF membrane) separation device 78 is provided.

In the low-pressure ultraviolet oxidizing device 75, the TOC is decomposed into _{organic acids and even CO 2} by the ultraviolet rays of 185 nm emitted from the low-pressure ultraviolet lamp. The organic matter and CO ₂ produced by the decomposition are removed by the non-regenerative ion exchange device 77 in the subsequent stage. In the ultrafiltration membrane 78, fine particles are removed, and outflow particles from the ion exchange resin are also removed.

Such ultrapure water W2 may be used by heating depending on the application. In this case, the treated water of the ion exchange device 77 is heated by the heat exchanger 81 and the heat pump 82 as the heating means, and then sent from the pipe 79 to the use point 80 as warm ultrapure water via the ultrafiltration membrane 78. Be done.

In the hot ultrapure water supply device as described above, the ultrapure water from the secondary pure water production device 70 is heated to about 55 to 80 ° C. by the heat exchanger 81 and the heat pump 82 and supplied to the use point 90. .. The return water from the use point 90 is circulated to the heat source side of the heat exchanger 81 via the return pipe 91. The return water that has passed through the heat source side of the heat exchanger 81 is returned to the sub tank 71 via the pipe 92 in a state where the temperature has dropped.

The hot ultra-pure water supply device as shown in FIG. 3 supplies a certain amount of warm ultra-pure water W3 to the use point 90, and returns the unused portion to the sub tank 71 via the return pipe 91, but at the use point 90. The amount of hot pure water used varies greatly depending on the operating conditions of the hot water using equipment (for example, a washing machine) at use point 90. Along with this, the amount of water in the return temperature ultrapure water W3 from the return pipe 91 also fluctuates greatly, and the energy on the heat source side of the heat exchanger 81 fluctuates, so that the heating requirement for the heat pump 82 changes. The heat pump 82 has a problem that when the heating load factor decreases, the coefficient of performance (heating COP), which is an index of the operating efficiency of the heat pump, decreases, resulting in inefficient operation.

Therefore, a large number of heat pumps 82 are provided in a large-scale hot and ultra-pure water supply device, and a large number of small-output heat pumps 82 are provided in a normal hot and cold water supply device to reduce the number of heat pumps 82 that operate when the heating load is low. Therefore, the heating COP of the heat pump 82 is maintained high even when the heating load is reduced.

However, since the control of the heat pump 82 determines the number of operating units according to the heating load at that time, the time lag from the heat pump 82 to the use point 90 to the heat exchanger 81 and the ever-changing use point 90 There is a problem that it is not always optimized in consideration of the fluctuation of the amount of hot pure water used in. Further, as the number of times of starting and stopping of the heat pump 82 increases, the risk of failure of the heat pump 82 increases, but as the number of heat pumps 82 increases, not only the possibility of failure increases, but also the maintenance cost for preventing this increases. There is a problem that the number increases.

The present invention has been made in view of the above-mentioned problems, and provides a method for controlling a heating means of a warm pure water supply device capable of improving energy efficiency by appropriately controlling the heating means. The purpose.

In view of the above object, the present invention has a pure water production apparatus and a plurality of heating means for heating the pure water from the pure water production apparatus, and supplies the heated warm pure water to a use point. It has a supply pipe and a return pipe from the use point to the pure water production apparatus, and uses water from the return pipe from the use point for preliminarily heating the pure water as a heat source in front of the heating means. It is a control method of the heating means of the warm pure water supply device having the first heat exchanger, and the operation of the heating means capable of improving the operation efficiency of the heating means based on the usage prediction data of the warm pure water of the use point. Provided is a method for controlling a heating means of a warm pure water supply device, which determines the number of units and controls the heating means based on the determined number of operating units (Invention 1).

According to the present invention (Invention 1), the amount of hot ultra-pure water used at the use point and the amount of water in the return pipe from the use point are in a contradictory relationship, and if the amount of hot ultra-pure water used at the use point is small, it returns. Since the amount of water in the pipe increases, the amount of heat of the first heat exchanger increases and the heating energy of the heating means is small, while the heating energy of the heating means is large if the amount of warm ultrapure water used at the point of use is large. You will need it. Therefore, by estimating the amount of warm pure water used at the use point from the operation demand of the use point, the energy required for the heating means is predicted with high accuracy. Then, the heating means can be suitably controlled in terms of energy efficiency by estimating the heating request to the warm pure water supply device from this prediction data and determining the stopping or operating number of the heating means. At this time, the number of operating units is determined so that the COP of the heating means can be maintained at a high level. As a result, the maintenance cost of the heating means and the energy consumption of the heating means can be optimized, so that the total lifetime cost at the point of use can be controlled to be optimized.

In the above invention (Invention 1), the heating means is a heat pump, and it is preferable to determine the number of operating units of the heating means so as to improve the operating efficiency of the heat pump (Invention 2). In particular, in the above invention (Invention 2), it is preferable that the heat pump has a heat medium circulation path, a liquid feeding means provided in the circulation path, and a heat medium heater (Invention 3).

According to such inventions (Inventions 2 and 3), the number of heat pumps in operation can be determined so that the COP of the heat pump can be maintained at a high level. As a result, the number of starts and stops of the heat pump can be optimized to optimize the maintenance cost of the heat pump and the energy consumption of the heat pump.

In the above inventions (Inventions 1 to 3), it is preferable to have a second heat exchanger using a part of the warm pure water as a heat source for preliminarily heating the pure water in front of the heating means (Invention 4). ).

According to the above invention (Invention 4), the pure water is further preliminarily heated before being heated by the heating means with concentrated water of the ultrafiltration membrane immediately before the point of use, thereby thermally heating the heating means. The load can be reduced and pure water can be heated more efficiently. Further, since the second heat exchanger uses a part of warm pure water as a heat source, the energy of excess warm pure water can be reused to improve energy efficiency.

In the above inventions (Inventions 1 to 4), it is preferable that the usage prediction data of the warm pure water at the use point is the prediction data of the change with time of the usage amount of the warm pure water (Invention 5).

According to the above invention (Invention 5), the accuracy of estimating the heating request to the warm pure water supply device is improved by using the predicted value of the change over time in the amount of hot pure water used. By determining, the heating means can be optimally controlled in terms of energy efficiency.

According to the method for controlling the heating means of the hot water supply device of the present invention, a method for controlling the number of operating units of the heating means so as to be able to improve the operating efficiency of the heating means based on the usage prediction data of the hot water at the point of use. Therefore, the heating means can be suitably controlled in terms of energy efficiency. At this time, the number of operating units can be determined so that the COP of the heating means can be maintained at a high level, so that the maintenance cost of the heating means and the energy consumption of the heating means can be optimized. It is possible to control the total lifetime cost in.

It is a block diagram which shows the warm pure water supply apparatus to which the control method of the heating means of the warm ultra-pure water supply apparatus by one Embodiment of this invention can be applied. It is a graph which shows an example of the method of determining the operating number of the heating means in the control method of the heating means of a warm ultra-pure water supply device. It is a schematic diagram which shows the conventional warm pure water supply device.

Hereinafter, an embodiment of a method for controlling the heating means of the warm pure water supply device of the present invention will be described with reference to the accompanying drawings.

(Hot ultra-pure water supply device)
The overall configuration of the warm ultra-pure water supply device of the present embodiment may be the same as that of the warm pure water supply device shown in FIG. 3 on the upstream side of the secondary pure water production device. explain.

In FIG. 1, the warm ultra-pure water supply device 1 supplies the warm ultra-pure water heated by the heating device 3 as a heating means to the use point 2. In this warm ultra-pure water supply device 1, the secondary pure water device 11 includes a sub tank 12 for storing the primary pure water W1, a pump 13, a cooler (heat exchanger) 14, a degassing film 15, and an ultraviolet oxidizing device. A liquid feed pump 17 and a non-regenerative ion exchange device 18 are provided. Then, the secondary pure water W2 produced by the secondary pure water device 11 can be supplied to the use point 2 via the supply pipe 21, and the warm pure water not used at the use point 2 returns. It is returned to the sub tank 12 via the pipe 23. A first heat exchanger 24 is provided in the middle of the return pipe 23 as a preheater for exchanging heat with the ultrapure water W2 flowing in the supply pipe 21. Reference numeral 22 denotes an ultrafiltration membrane provided at the end of the supply pipe 21, and the concentrated water of the ultrafiltration membrane 22 is returned to the sub tank 12 via the concentrated water return pipe 25. A second heat exchanger 26 as a preheater for exchanging heat with the ultrapure water W2 circulating in the supply pipe 21 is provided in the middle of the concentrated water return pipe 25. In the present embodiment, for convenience of explanation, the water before the treatment with the ultrafiltration membrane 22, that is, after the treatment with the non-regenerative ion exchange device 18, is referred to as ultrapure water W2.

In the hot ultra-pure water supply device 1 as described above, the heating device 3 includes a water circulation path 31 as a heat medium, a tank 32 of the water, and a liquid supply pump 33 as a liquid supply means, and the circulation path 31. Is provided with a heat recovery chiller 34 as a heater for recovering the heat of the production cooling water circulation device 35. A heat pump as a heating means is configured by the circulation path 31, the liquid feed pump 33, and the heat recovery chiller 34. In the present embodiment, a plurality of heat pumps, for example, about 2 to 10 units, for example, 4 units are provided, and the number of heat pumps can be controlled according to the temperature of the water flowing through the circulation path 31. On the downstream side of the heat recovery chiller 34, a hot water heater 36 using water vapor as a heat source is provided in the circulation path 31, and heat is generated between the heat recovery chiller 34 and the ultrapure water W2 circulating in the supply pipe 21 on the downstream side thereof. A warm pure water heater 37 for replacement is provided.

(Manufacturing method of warm pure water)
Next, a method for producing warm pure water using the warm ultra-pure water supply device 1 as described above will be described below.

The primary pure water W1 is introduced from the sub tank 12 into the secondary pure water device 11, and is treated by the degassing film 15, the ultraviolet oxidizing device 16 and the non-regenerative ion exchange device 18, so that the ultrapure water W2 at about 23 ° C. is obtained. Manufactured. The produced ultrapure water W2 is heated to about 25 ° C. in the second heat exchanger 26, and then to about 33 to 35 ° C. in the first heat exchanger 24.

On the other hand, the water circulating in the circulation path 31 reaches about 53 to 59 ° C. in the tank 32 by circulating, and is heated to about 60 ° C. by recovering the heat of the production cooling water, and further from the boiler or the like. It is heated to about 70 ° C. by a hot water heater 36 using steam (steam) as a heat source, and reaches a hot pure water heater 37.

Then, the ultrapure water W2 is heated to about 60 ° C. by the warm pure water heater 37. Since the ultrafiltration membrane 22 is installed immediately before the use point 2 in the supply pipe 21, fine particles in the warm ultrapure water W3 are removed and supplied to the use point 2 at 57 to 60 ° C. The supply amount of the warm ultrapure water W3 is a quantification set to be larger than the maximum usage amount of the use point 2. The concentrated water of the ultrafiltration membrane 22 is returned from the concentrated water return pipe 25 to the sub tank 12, and at this time, becomes a heat source of the second heat exchanger 26 provided in the middle of the concentrated water return pipe 25. Then, the hot ultra-pure water W3 unused at use point 2 becomes a heat source of the first heat exchanger 24 provided in the middle of the return pipe 23 from the return pipe 23, and after the temperature is lowered to about 40 ° C., it is returned to the sub tank 12. Will be done.

(Control method of heating device 3)
In the present embodiment, the heating device 3 is controlled as follows.

First, time-series data of the past operating status of equipment such as the washing machine at use point 2 and the amount of hot ultra-pure water W3 used are obtained in advance. Then, based on this past time-series data, time-series prediction data of the future usage of warm ultra-pure water W3 is created from the future operation status (demand) of equipment such as a washing machine at use point 2. If the amount of warm pure water used can be easily predicted from the operation plan of use point 2 even if there is no past time series data, it is not necessary to obtain the past time series data of the equipment of use point 2 in advance. good.

At this time, the optimum control of the number of operating heat pumps is determined from the viewpoint of the heating COP of the heat pump and the number of starts and stops from the series data. This is because if all the heat pumps are operated in a state where the heat load is low, the heating COP is lowered and the energy efficiency is deteriorated. Therefore, for example, the number of heat pumps whose heating COP is equal to or higher than a predetermined value may be set based on the amount of hot ultra-pure water W3 used. That is, if the amount of use point 2 used is small, the flow rate of the return pipe 23 increases, so that the heat source of the first heat exchanger 24 increases, and the ultrapure water W2 after heat exchange in the first heat exchanger 24 As the temperature rises, the heating load for heating to about 60 ° C. with the warm pure water heater 37 becomes smaller. Therefore, if the number of operating heat pumps is the same, the heating COP of the heat pump decreases. Therefore, the number of operating heat pumps may be reduced so that the heating COP becomes a predetermined value or more. It is desirable that this heating COP is high in terms of energy efficiency, but it may be set in an appropriate range according to the capacity of the heat pump. For example, it is set in the range of heating COPs 4 to 6, and the heating COP becomes as high as possible in this range. The number of operating heat pumps may be set as described above.

Although the heat pump can be made more efficient in terms of heating COP by such control, the amount of hot ultra-pure water W3 used may drop sharply in a short time and recover depending on the operating condition of the equipment at use point 2. be. Even in such a case, it is possible to follow up by controlling the number of operating heat pumps, but since it is a short time, the number of times the heat pump is started and stopped is large in order to improve the operating efficiency of the heat pump. It will increase. As a result, the risk of heat pump failure increases. Therefore, if it is predicted from the time-series data of the future usage of warm ultrapure water W3 that the usage will recover in a short time, for example, about 10 minutes or less, In anticipation of this, it is preferable not to control the number of heat pumps.

By controlling the number of heat pumps in the heating device 3 based on the demand prediction of use point 2 as described above, compared with the case where all the heat pumps are always operated or one large heat pump is operated. Since the heating COP of the heat pump can be maintained large, the operating energy (operating cost) of the heat pump can be reduced. At this time, it is preferable to control each heat pump to start and stop in order so that the number of times of starting and stopping of each heat pump is leveled.

Since the operation number control of this heat pump is based on the prediction, a time lag may occur with respect to the actual amount of hot pure water used at use point 2. Therefore, it is preferable to control while operating the actual machine while making corrections so as to match the amount of warm pure water used in the actual use point 2. The above-mentioned control is preferably performed by a CPU (Central Processing Unit), a computer having a storage unit including a flash memory, a ROM, a RAM, a hard disk, or the like. In addition, it is possible to make the prediction of the amount of warm pure water more accurate by accumulating the relationship between the operating status of use point 2 and the amount of hot pure water used over a long period of time, analyzing the tendency by machine learning, and making corrections. can.

Although the control method of the heating means of the warm pure water supply device of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the temperature setting of the warm pure water is not limited to the above-described embodiment, and further, the hot pure water at a high temperature or a low temperature can be applied. Further, the configurations of the primary pure water device and the secondary pure water device 11 are not particularly limited, and can be applied to various configurations. Further, as the heat source of the heat pump, not only the production cooling water but also various waste heat such as chiller drainage can be used. Furthermore, although the case of the warm ultra-pure water supply device has been described in this embodiment, the same can be applied to a warm pure water supply device that does not have a secondary pure water supply device.

The present invention will be further described based on the following specific examples.

(Comparative Example 1)
In FIG. 1, four heat pumps of the hot ultra-pure water supply device 1 having four heat pumps were constantly operated to supply a predetermined amount of hot ultra-pure water W3 at 57 to 60 ° C. to use point 2. The temperature of the ultrapure water W2 immediately after production is 23 ° C., and the temperature of the ultrapure water W2 is adjusted to 25 ° C. by the second heat exchanger 26, 33 to 52 ° C. by the first heat exchanger 24, and 60 ° C. by the warm pure water heater. It was warm. Further, in the heating device 3, the outlet temperature of the water pump 33, which is the heating medium, was 53 to 59 ° C., and the heat recovery chiller 34 heated the temperature to 60 ° C. and the hot water heater 36 heated the temperature to 70 ° C.

(Example 1)
As shown in FIG. 3, based on the time-series data of the operating status of the washing machine equipment at use point 2 and the amount of hot ultra-pure water used, the use of warm ultra-pure water at use point (POU) based on the operation plan of use point 2. We created time-series forecast data for quantities. Then, based on the predicted data of the usage amount, it is assumed that the number of heat pumps is 4 to supply the hot ultra-pure water W3 to the use point 2 by the hot ultra-pure water supply device 1, and the heating COP of the heat pump is 4.5 to 5. The number of heat pumps in operation was set so as to be within the range of 0. At this time, even if the amount of warm ultra-pure water used at the point of use decreases, if it is predicted that the decrease time is 10 minutes or less (the part indicated by the broken line in FIG. 3), the heat pump We decided to maintain the number of operating units.

The ultrapure water W2 immediately after production is heated under the same temperature conditions as in Comparative Example 1 except that the number of heat pumps in operation is controlled as shown in FIG. The same amount as in Example 1 was supplied.

As a result of the above operation, in Example 1, the operating power consumption was reduced as compared with Comparative Example 1, and the operating cost of the entire hot ultra-pure water supply device 1 could be reduced by about 15%. It is considered that this is because the heating COP of the heat pump can be maintained higher in the first embodiment.

1 Warm ultra-pure water supply device (warm pure water supply device)
2 Use point 3 Heating device 11 Secondary pure water device 12 Sub tank 13 Pump 14 Cooler (heat exchanger)
15 Degassing membrane 16 Ultraviolet oxidizing device 17 Liquid transfer pump 18 Non-regenerative ion exchange device 21 Supply pipe 22 Ultrafiltration membrane 23 Return pipe 24 First heat exchanger (preheater)
25 Concentrated water return pipe 26 Second heat exchanger (preheater)
31 Circulation path (heat pump)
32 Tank 33 Liquid transfer pump (heat pump)
34 Heat recovery chiller (heater, heat pump)
35 Production cooling water circulation device 36 Hot water heater 37 Hot pure water heater W1 Primary pure water W2 Secondary pure water (ultra pure water)
W3 warm ultra-pure water

Claims (5)

A supply pipe having a pure water production apparatus and a plurality of heating means for heating the pure water from the pure water production apparatus and supplying the heated warm pure water to the use point, and the above from the use point. It has a return pipe to a pure water production apparatus, and has a first heat exchanger using water from the return pipe from a use point for preliminarily heating the pure water as a heat source in front of the heating means. It is a control method of the heating means of the warm pure water supply device.
Based on the usage prediction data of warm pure water at the use point, the number of operating units of the heating means capable of improving the operating efficiency of the heating means is determined.
The heating means is controlled based on the determined number of operating units.
A method of controlling the heating means of the warm pure water supply device. The heating means is a heat pump.
The method for controlling a heating means of a warm pure water supply device according to claim 1, wherein the number of operating units of the heating means is determined so as to improve the operating efficiency of the heat pump. The method for controlling a heating means of a warm pure water supply device according to claim 2, wherein the heat pump has a heat medium circulation path, a liquid feeding means provided in the circulation path, and a heat medium heater. The warm pure water supply device according to any one of claims 1 to 3, further comprising a second heat exchanger using a part of the warm pure water as a heat source in front of the heating means. How to control the heating means. The method for controlling a heating means of a warm pure water supply device according to any one of claims 1 to 4, wherein the hot pure water usage prediction data of the use point is prediction data of a change over time in the amount of warm pure water used.

Images