Energy-saving system for pure water system of semiconductor factory

Abstract

The application discloses a kind of semiconductor factory pure water system energy-saving system, it is related to semiconductor cooling technical field, adopt outer ring inner bucket type double-bin structure, set up small bypass heat exchange pipeline, cooling water unit waste heat recovery system and ultrapure water system are integrated, through the 316L stainless steel single-layer storage tank outer wall in cooling water storage tank and the 316L stainless steel coil pipe heat exchanger in RO storage tank indirect heat exchange of cooling water unit cooling water and RO raw water is realized, cooperate with multi-point temperature measurement and PLC linkage control each electric valve opening degree and cooling tower start-stop timing.This scheme can control RO inlet water temperature in 20-25 ℃ optimal interval, without additional electric heating device, while reducing cooling tower running time and evaporation water consumption, realize waste heat resource utilization, solve the problem of existing technology heat source seasonal interruption, energy and water resource double waste, significantly reduce the comprehensive operation cost of semiconductor factory pure water system, improve energy utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor cooling technology, and more specifically to an energy-saving system for a pure water system in a semiconductor plant. Background Technology

[0002] Semiconductor manufacturing processes have stringent requirements for the quality, quantity, and temperature of ultrapure water. In ultrapure water production systems, the permeate flux of reverse osmosis membranes is significantly positively correlated with the feed water temperature. Within the range of 15-30℃, for every 1℃ increase in water temperature, the permeate flux of the reverse osmosis membrane increases by approximately 3%. To ensure stable permeate efficiency in ultrapure water systems, appropriate temperature control of the reverse osmosis feed water is commonly required in the industry. Meanwhile, semiconductor plants' process equipment and cleanroom air conditioning systems require numerous chillers to provide cooling. During chiller operation, a significant amount of low-temperature waste heat (30-37℃) is generated on the condenser side. Efficiently utilizing this waste heat while simultaneously addressing the heating needs of the ultrapure water system has become a pressing technological direction for optimization within the industry.

[0003] Currently, the mainstream heating methods for ultrapure water systems are mainly divided into two categories: boiler hot water heat exchange and electric heating. Boiler hot water heat exchange systems indirectly heat the reverse osmosis feed water using hot water generated by the plant's boilers via plate heat exchangers. However, this solution relies on the stable operation of the boiler system throughout the year. Most semiconductor plants' boilers only operate during the heating season, and cannot provide heat when shut down during the non-heating season, resulting in lower reverse osmosis feed water temperatures in spring, summer, and autumn, significantly reducing water production efficiency. Electric heating systems, on the other hand, use electric heaters in the reverse osmosis pretreatment section to directly heat the feed water. While this solution ensures stable water temperature, it consumes a huge amount of electricity, significantly increasing the annual electricity consumption for electric heating alone and thus increasing the cost of ultrapure water production. As for the waste heat generated by the chiller units, current technologies generally use open cooling towers to cool the cooling water through evaporative cooling.

[0004] Therefore, how to reduce resource consumption while meeting the heating requirements of ultrapure water systems is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides an energy-saving system for a semiconductor plant's pure water system to solve the problems existing in the background art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An energy-saving system for a semiconductor plant's pure water system includes: a chiller unit, a cooling water circulation main loop, an outer ring inner barrel-type dual-compartment heat exchange storage tank, a small bypass heat exchange loop, and a multi-point temperature measurement PLC linkage control system. The outer ring inner barrel type dual-compartment heat exchange storage tank includes an outer ring cooling water storage tank and an inner RO raw water tank. The cooling water storage tank is arranged around the outside of the RO raw water tank to form a dual-compartment structure. The main cooling water circulation loop includes a chiller unit, cooling water pipes, a first electric regulating valve, a cooling tower, a cooling water storage tank, a second electric regulating valve, and a cooling water pump connected in sequence, and then returns to the chiller unit. The small bypass heat exchange circuit includes a small bypass pipe, a coil heat exchanger installed inside the RO raw water tank, and a third electric regulating valve. The small bypass pipe branches off from below the first electric regulating valve of the cooling water circulation main circuit, passes through the coil heat exchanger and the third electric regulating valve, and then flows into the cooling water pump before returning to the chiller unit. The multi-point temperature measurement PLC linkage control system includes multiple temperature sensors and a PLC controller. The PLC controller is connected to each temperature sensor, each electric regulating valve, and the cooling tower fan, and controls the opening of each electric regulating valve and the start and stop of the cooling tower fan according to the temperature detection signal.

[0007] Preferably, the cooling water storage tank is made of concrete and lined with a fiberglass resin layer for leak-proof, corrosion-proof and heat-insulating treatment, and the exterior of the cooling water storage tank is provided with a polyurethane insulation layer.

[0008] Preferably, the RO raw water tank is made of a single-layer 316L stainless steel tank, and the coil heat exchanger is made of 316L stainless steel coil heat exchanger, which is immersed in the raw water inside the RO raw water tank.

[0009] Preferably, the cooling water storage tank adopts a top-inlet and bottom-outlet water flow structure, with cooling water entering from the top of the cooling water storage tank and flowing out from the bottom back to the chiller unit, ensuring that the lower part of the cooling water flows back to the chiller unit.

[0010] Preferably, the water supply pipeline is divided into two pipelines, each equipped with a fourth electric regulating valve and a fifth electric regulating valve. The fourth electric regulating valve is located on the pipeline connecting the cooling water storage tank and the RO raw water tank, and the fifth electric regulating valve is located on the pipeline connecting the cooling water storage tank. The RO raw water tank is equipped with an RO raw water pipeline, through which tap water is supplied from the bottom and output from the upper middle section via the RO raw water pipeline.

[0011] Preferably, the top of the cooling water storage tank is provided with a cooling water tank overflow port.

[0012] As can be seen from the above technical solution, compared with the prior art, the present invention discloses an energy-saving system for a semiconductor plant's pure water system. By integrating and optimizing the waste heat recovery of the chiller unit with the heating of the ultrapure water system's inlet water, and adopting an inner tank-type dual-compartment structure and a small bypass heat exchange design, the system achieves the resource utilization of low-temperature waste heat. This not only completely eliminates the RO front-end electric heater, significantly reducing heating energy consumption, but also reduces cooling tower operating time and evaporation water consumption, and lowers the dosage of scale inhibitor and the maintenance cost of packing material. Through multi-point temperature measurement and PLC linkage control, stable control can be achieved throughout the year. The RO feed water temperature is optimally set between 20-25℃, effectively ensuring the water production efficiency of the reverse osmosis membrane and solving the problem of heat source interruption during the non-heating season. The dual-compartment structure achieves complete isolation between the cooling water and the RO feed water, allowing the use of softened water or scale inhibitors on the outer ring cooling water side without affecting the RO feed water quality. The small bypass heat exchange design can prevent the chiller unit condenser from being protected from excessively low temperatures when the cooling load is low in winter, while also achieving energy storage and heat storage, peak shaving and valley filling. Overall, it significantly reduces the comprehensive operating costs of the semiconductor plant's pure water system and chiller unit system, and improves the efficiency of energy and water resource utilization. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure provided by the present invention; In the diagram: 1 Chiller unit; 2 Cooling water pipeline; 3 First electric regulating valve; 4 Cooling tower; 5 Cooling water storage tank; 6 Cooling water tank overflow port; 7 Second electric regulating valve; 8 Cooling water pump; 9 Small bypass pipeline; 10 Coil heat exchanger; 11 Third electric regulating valve; 12 RO raw water tank; 13 Makeup water pipeline; 14 Fourth electric regulating valve; 15 Fifth electric regulating valve; 16 RO raw water pipeline. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] This invention discloses an energy-saving system for a semiconductor plant's pure water system, such as... Figure 1As shown, it includes: chiller unit 1, cooling water circulation main circuit, outer ring inner barrel type double-compartment heat exchange storage tank, small bypass heat exchange circuit and multi-point temperature measurement PLC linkage control system; The outer ring inner barrel type dual-compartment heat exchange storage tank includes an outer ring cooling water storage tank 5 and an inner RO raw water tank 12. The cooling water storage tank 5 is arranged around the outside of the RO raw water tank 12 to form a dual-compartment structure. The main cooling water circulation loop includes a chiller unit 1, a cooling water pipe 2, a first electric regulating valve 3, a cooling tower 4, a cooling water storage tank 5, a second electric regulating valve 7, and a cooling water pump 8 connected in sequence, and then returns to the chiller unit 1. The small bypass heat exchange circuit includes a small bypass pipe 9, a coil heat exchanger 10 installed inside the RO raw water tank 12, and a third electric regulating valve 11. The small bypass pipe 9 branches off from below the first electric regulating valve 3 of the main cooling water circulation circuit, passes through the coil heat exchanger 10 and the third electric regulating valve 11, and then flows into the cooling water pump 8, and then returns to the chiller unit 1. The multi-point temperature measurement PLC linkage control system includes multiple temperature sensors and a PLC controller. The PLC controller is connected to each temperature sensor, each electric regulating valve, and the cooling tower fan 4, and controls the opening of each electric regulating valve and the start and stop of the cooling tower fan 4 according to the temperature detection signal.

[0017] In one specific embodiment, the cooling water storage tank 5 is made of concrete and lined with a fiberglass resin layer for leak-proof, corrosion-proof and heat-insulating treatment. The exterior of the cooling water storage tank 5 is provided with a polyurethane insulation layer.

[0018] In one specific embodiment, the RO raw water tank 12 is made of a single-layer 316L stainless steel tank, and the coil heat exchanger 10 is made of 316L stainless steel coil heat exchanger. The coil heat exchanger 10 is immersed in the raw water inside the RO raw water tank 12.

[0019] In one specific embodiment, the cooling water storage tank 5 adopts a top-inlet and bottom-outlet water flow structure, with cooling water entering from the top of the cooling water storage tank 5 and flowing out from the bottom back to the chiller unit 1, ensuring that the lower part of the cooling water flows back to the chiller unit 1.

[0020] In one specific embodiment, the water supply pipeline is divided into two pipelines, each equipped with a fourth electric regulating valve 14 and a fifth electric regulating valve 15. The fourth electric regulating valve 14 is located on the pipeline connecting the cooling water storage tank 5 and the RO raw water tank 12, and the fifth electric regulating valve 15 is located on the pipeline connected to the cooling water storage tank 5. The RO raw water tank 12 is equipped with an RO raw water pipeline 16, through which tap water is supplied from the bottom and output via the upper section of the RO raw water pipeline 16. The fifth electric regulating valve 15 is used for regulating the supply of cooling water to the outer ring chamber.

[0021] In one specific embodiment, a cooling water tank overflow port 6 is provided on the top of the cooling water storage tank 5.

[0022] The process flow 1 is as follows: Under normal operating conditions, the cooling water from the chiller unit 1 flows through the cooling water pipe 2, through the first electric regulating valve 3 (fully open), through the cooling tower 4 (the fan is set to start at 37°C and stop at 32°C), through the cooling water storage tank 5 (which adopts an upper inlet and lower outlet method to ensure that the lower cooling water returns to the chiller unit 1), through the second electric regulating valve 7 (fully open), through the cooling water pump 8, and back to the chiller unit 1.

[0023] Process 2: Tap water is supplied to the RO water tank via the fourth electric regulating valve 14 through the water supply pipe 13. After the tank wall is heated by heat exchange (20-25℃), the water is sent to the RO device of the ultrapure water system via the RO raw water pipe 16.

[0024] Process 3: During the transitional season or in some areas where winter temperatures are low, to avoid excessively low cooling water temperatures or RO raw water tank 12 water temperatures failing to meet standards, the opening of the first electric regulating valve 3 and the second electric regulating valve 7 is reduced by PLC automatic control, while the opening of the third electric regulating valve 11 is increased. This allows the cooling water to bypass heat exchange through the small bypass pipe 9, the coil heat exchanger 10, the third electric regulating valve 11, the cooling water pump 8, and the chiller unit 1, reducing heat consumption and ensuring that the cooling water does not fall below the lower limit of the temperature range. This ensures the normal operation of the chiller and also keeps the RO raw water tank 12 water temperature within the normal range.

[0025] Features of this invention: 1. Both storage tanks utilize a double-compartment structure with an outer ring and an inner cylinder. The cooling water tank is constructed of concrete, lined with fiberglass resin for leak-proofing, corrosion protection, and heat insulation, and externally insulated with polyurethane. The RO water tank is made of a single layer of 316L stainless steel, enabling rapid heat exchange and providing corrosion resistance. The double-compartment structure allows for the use of softened water or scale inhibitors in the outer compartment without affecting the water quality inside the RO feed tank.

[0026] 2. The system employs a small bypass heat exchanger, which can reduce heat loss without opening the main circulation loop in areas with lower winter cooling loads, preventing the chiller condenser temperature from becoming too low and triggering protection. Simultaneously, it effectively transfers heat to the coil heat exchanger in the RO raw water tank, ensuring the RO raw water temperature meets the required standards.

[0027] 3. The system adopts multi-point temperature measurement and PLC linkage control, which can accurately control the opening degree of electric valves and the opening and closing timing of cooling tower fans, effectively ensuring the stable operation of the entire system.

[0028] 4. Tap water is supplied from the bottom of the water tank, with the low-temperature water sinking. The cooling water tank returns water from the bottom, ensuring the low-temperature water returns to the chiller unit and maintains the cooling effect. Tap water is supplied from the bottom of the RO raw water tank, without disturbing the upper layer of warm water. The raw water going to the RO is taken from the upper part of the storage tank to ensure uniform heat exchange before output.

[0029] Related Explanation: Due to its large volume, the outer ring and inner tank-type dual-compartment structure also serves as an energy storage and heat storage system. Waste heat recovery from chiller cooling water – energy storage – utilizes waste heat in the energy storage tank to raise the temperature of the RO pretreatment inlet water, optimizing water production efficiency. When the RO inlet water temperature is between 15-30℃, for every 1℃ increase in temperature, the RO water production increases by approximately 3%. If the temperature is too low, the water production decreases sharply. The optimal RO inlet water temperature is 20-25℃, and the temperature is controlled within this range after heat exchange. This design utilizes the waste heat from the chiller unit to preheat the RO raw water, eliminating the need for an electric preheater at the RO front end and significantly reducing heating energy consumption. The water storage tank smooths out peak and valley loads, storing excess heat from the unit at night and using it for RO heating during the day, reducing cooling tower operating time, cooling tower energy consumption, and evaporation losses.

[0030] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The methods disclosed in the embodiments are described simply because they correspond to the methods disclosed in the embodiments; relevant parts can be found in the method section.

[0031] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An energy-saving system for a semiconductor plant's pure water system, characterized in that, include: Chiller unit, cooling water circulation main circuit, outer ring inner barrel type dual-compartment heat exchange storage tank, small bypass heat exchange circuit and multi-point temperature measurement PLC linkage control system. The outer ring inner barrel type dual-compartment heat exchange storage tank includes an outer ring cooling water storage tank and an inner RO raw water tank. The cooling water storage tank is arranged around the outside of the RO raw water tank to form a dual-compartment structure. The main cooling water circulation loop includes a chiller unit, cooling water pipes, a first electric regulating valve, a cooling tower, a cooling water storage tank, a second electric regulating valve, and a cooling water pump connected in sequence, and then returns to the chiller unit. The small bypass heat exchange circuit includes a small bypass pipe, a coil heat exchanger installed inside the RO raw water tank, and a third electric regulating valve. The small bypass pipe branches off from below the first electric regulating valve of the cooling water circulation main circuit, passes through the coil heat exchanger and the third electric regulating valve, and then flows into the cooling water pump before returning to the chiller unit. The multi-point temperature measurement PLC linkage control system includes multiple temperature sensors and a PLC controller. The PLC controller is connected to each temperature sensor, each electric regulating valve, and the cooling tower fan, and controls the opening of each electric regulating valve and the start and stop of the cooling tower fan according to the temperature detection signal.

2. The energy-saving system for a semiconductor plant pure water system according to claim 1, characterized in that, The cooling water storage tank is made of concrete and lined with a fiberglass resin layer for leak-proof, corrosion-proof and heat-insulating treatment. The exterior of the cooling water storage tank is provided with a polyurethane insulation layer.

3. The energy-saving system for a semiconductor plant pure water system according to claim 1, characterized in that, The RO raw water tank is made of a single-layer 316L stainless steel tank, and the coil heat exchanger is made of 316L stainless steel coil heat exchanger. The coil heat exchanger is immersed in the raw water inside the RO raw water tank.

4. The energy-saving system for a semiconductor plant pure water system according to claim 1, characterized in that, The cooling water storage tank adopts a top-inlet and bottom-outlet water flow structure. Cooling water enters from the top of the cooling water storage tank and flows out from the bottom back to the chiller unit, ensuring that the lower cooling water flows back to the chiller unit.

5. The energy-saving system for a semiconductor plant pure water system according to claim 1, characterized in that, It also includes a water supply pipeline, which is divided into two pipelines. A fourth electric regulating valve and a fifth electric regulating valve are respectively installed on the two pipelines. The fourth electric regulating valve is installed on the pipeline that passes through the cooling water storage tank and connects to the RO raw water tank, and the fifth electric regulating valve is installed on the pipeline that connects to the cooling water storage tank. The RO raw water tank is equipped with an RO raw water pipeline. Tap water is supplied from the bottom of the RO raw water tank and output through the middle and upper sections of the RO raw water pipeline.

6. The energy-saving system for a semiconductor plant pure water system according to claim 1, characterized in that, The top of the cooling water storage tank is equipped with a cooling water tank overflow port.

Images