Sea water pump frequency conversion control system suitable for iCER system

By designing a variable frequency control system for seawater pumps suitable for the iCER system, and optimizing the operation of the seawater pumps using sensors and logic control, the problems of cooling water temperature requirements and wasted power of seawater pumps in the iCER system were solved, achieving energy saving and improved system stability.

CN223634871UActive Publication Date: 2025-12-05DALIAN SHIPBUILDING INDUSTRY CO LTD
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Patent Information

Application Number
CN202423019331.8
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-12-09
Publication Date
2025-12-05
Estimated Expiration
2034-12-09

AI Technical Summary

Technical Problem

Existing technologies cannot meet the new requirements of iCER systems for cooling water temperature, and the power consumption of seawater pumps is seriously wasted at low temperatures. Therefore, it is necessary to design a variable frequency control system for seawater pumps suitable for iCER systems to optimize energy use.

Method used

A variable frequency control system for seawater pumps was designed. The system monitors seawater temperature and pressure through sensors and controls the speed and flow rate of the seawater pumps using logic. This ensures the normal operation of the cooling system and reduces the power consumption of the seawater pumps. The system includes the connection of high-level and low-level seabed tanks, seawater main pipe, seawater pumps, and central and iCER system plate heat exchangers. It also sets minimum speed and standby pumps to achieve automated monitoring and alarm functions.

Benefits of technology

This approach minimizes seawater pump power consumption while ensuring the normal operation of the iCER and cryogenic freshwater cooling system, thereby improving the automation and stability of ship operation and reducing operating costs.

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Abstract

The utility model discloses a seawater pump frequency conversion control system suitable for an iCER system. A high-position seabed box and a low-position seabed box are respectively connected with an iCER system plate heat exchanger and a central plate heat exchanger through a seawater header pipe via a seawater pump; and the iCER system plate heat exchanger is connected with an iCER low-temperature fresh water cooling system user, and returns to the iCER system plate heat exchanger after connection. And the central plate heat exchanger is connected with a low-temperature fresh water cooling system user through a three-way temperature control valve and a low-temperature fresh water lightering pump, and then returns to the central plate heat exchanger and the three-way temperature control valve. Under the condition of ensuring normal operation of the central fresh water cooling system and the iCER system, the power of the sea water pump can be reduced to the greatest extent, the purpose of saving energy is achieved, automatic operation and comprehensive monitoring of the low-temperature fresh water cooling system are realized to the greatest extent through design and logic control of the sensors, and the system is suitable for popularization and application. And the working intensity in the ship operation is reduced, the automatic operation level of the ship is provided, and the ship operation is more stable and safer.
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Description

TECHNICAL FIELD

[0001] The application belongs to the field of offshore ship design and construction, and particularly relates to a seawater pump variable frequency control system suitable for an iCER system. BACKGROUND

[0002] A conventional ship low-temperature fresh water cooling system is to transport external seawater through a seawater pump, enter a central plate heat exchanger, and then cool the low-temperature fresh water system, and the low-temperature fresh water system provides 36 DEG C cooling fresh water to the equipment needing cooling in the ship through a three-way temperature control valve mixed water mode.

[0003] However, with the technical update of the main engine patent merchant, the current main engine requires that the cooling water temperature provided to the main engine is as low as possible, the MAN B&W main engine requires that the set temperature of the three-way temperature control valve is 10 DEG C, and the WinGD main engine requires that the set temperature of the three-way temperature control valve is 25 DEG C.

[0004] In addition, when the external seawater temperature is low, the cooling efficiency of the seawater is greatly improved, and the seawater pump designed according to the set temperature of 32 DEG C can provide too much seawater, causing waste of the seawater pump electric power, therefore, considering the operation cost of the ship, more and more ship owners choose to design the seawater pump to be variable frequency, that is, in the case that the seawater temperature is low, the power of the seawater pump is reduced, the seawater flow is reduced, under the premise of meeting the cooling system requirements, the consumption of the seawater pump electric power is minimized, and energy is saved.

[0005] The iCER is a system using a dual-fuel main engine newly launched by WinGD, and the cooling system thereof also needs to be provided with cooling seawater by the seawater pump.

[0006] Therefore, while meeting the normal operation of the low-temperature fresh water cooling system, the cooling water system of the iCER also needs to be considered to be normally operated. A simple variable frequency control logic cannot meet the requirements, and a seawater pump variable frequency control system suitable for the iCER system needs to be designed. SUMMARY

[0007] To solve the above problems, the application provides a seawater pump variable frequency control system suitable for an iCER system, which aims to simultaneously ensure the normal operation of a ship low-temperature fresh water cooling system and an iCER cooling water system, and to minimize the power of the seawater pump, and to save energy to the maximum extent under the premise of ensuring the normal operation of the ship system, and the technical scheme adopted by the application is that:

[0008] A seawater pump frequency conversion control system suitable for an iCER system, a high-position subsea tank and a low-position subsea tank are connected with a plate heat exchanger of the iCER system and a central plate heat exchanger through a seawater main pipe via a seawater pump respectively; the plate heat exchanger of the iCER system is connected with a user of an iCER low-temperature fresh water cooling system, and returns to the plate heat exchanger of the iCER system after the connection; the central plate heat exchanger is connected with the user of the low-temperature fresh water cooling system via a low-temperature fresh water transfer pump through a three-way temperature control valve, and returns to the central plate heat exchanger and the three-way temperature control valve after the connection.

[0009] A seawater pump inlet is provided with a seawater pump inlet differential pressure sensor, a low-temperature seawater inlet of the central plate heat exchanger is provided with a temperature sensor, a low-temperature seawater outlet of the central plate heat exchanger is provided with a temperature sensor, a low-temperature seawater inlet of the central plate heat exchanger is provided with a temperature sensor and a pressure sensor, a low-temperature fresh water outlet of the central plate heat exchanger is provided with a temperature sensor, a seawater inlet of the plate heat exchanger of the iCER system is provided with a temperature sensor, a seawater outlet of the plate heat exchanger of the iCER system is provided with a temperature sensor, and a seawater pump frequency conversion control system control box is connected with each temperature sensor and pressure sensor.

[0010] The seawater pump frequency conversion control system suitable for the iCER system according to the claim is characterized in that the minimum rotating speed of the seawater pump frequency conversion is set as the maximum rated rotating speed.

[0011] The seawater pump frequency conversion control system suitable for the iCER system is further characterized in that there are two seawater pumps, one of which is a standby seawater pump, and the seawater pump frequency conversion control system control box automatically starts the standby seawater pump when the differential pressure sensor of the seawater pump inlet detects that the seawater pressure is less than or equal to 0.5 MPa.

[0012] The seawater pump frequency conversion control system suitable for the iCER system is further characterized in that the maximum temperature of seawater entering the central plate heat exchanger is 32℃.

[0013] The seawater pump frequency conversion control system suitable for the iCER system is further characterized in that the temperature difference of the central plate heat exchanger is 12℃-16℃.

[0014] The seawater pump frequency conversion control system suitable for the iCER system is further characterized in that the set temperature of the three-way temperature control valve is 25℃.

[0015] The seawater pump frequency conversion control system suitable for the iCER system is further characterized in that the temperature difference between the low-temperature fresh water outlet of the central plate heat exchanger and the low-temperature seawater inlet of the central plate heat exchanger is set as 5℃.

[0016] The application meets the requirements of the host with the iCER system for the low-temperature fresh water cooling system at present, can reduce the power of the sea water pump as much as possible under the condition that the central fresh water cooling system and the iCER system are normally operated, achieves the purpose of saving energy, and through the design of the sensor and the logic control, the automatic operation and comprehensive monitoring of the low-temperature fresh water cooling system are realized as much as possible, the working strength in the ship operation is reduced, the level of the automatic operation of the ship is provided, and the ship operation is more stable and safe. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic diagram of the system of the application;

[0018] Among them, 1 is a low seabed tank, 2 is a high seabed tank, 3 is a sea water main, 4 is a sea water pump, 5 is an iCER system plate heat exchanger, 6 is a central plate heat exchanger, 7 is a low-temperature fresh water cooling system three-way temperature control valve, 8 is a low-temperature fresh water transfer pump, 9 is a central plate heat exchanger low-temperature fresh water outlet temperature sensor, 10 is a central plate heat exchanger low-temperature fresh water inlet temperature sensor, 11 is an iCER system plate heat exchanger sea water outlet temperature sensor, 12 is an iCER system plate heat exchanger sea water inlet temperature sensor, 13 is a central plate heat exchanger low-temperature sea water outlet temperature sensor, 14 is a central plate heat exchanger low-temperature sea water inlet temperature sensor, 15 is a central plate heat exchanger low-temperature sea water inlet pressure sensor, 16 is a sea water pump inlet and outlet pressure difference sensor, 17 is a sea water pump frequency conversion control system control box, 18 is a low-temperature fresh water cooling system user, and 19 is an iCER low-temperature fresh water cooling system user. DETAILED DESCRIPTION

[0019] The application is further described in combination with the drawings. EMBODIMENT

[0020] The sea water enters the sea water main 3 through the high seabed tank 2 and the low seabed tank 1, and the sea water pump 4 transfers the sea water to the iCER system plate heat exchanger 5 and the central plate heat exchanger 6 to cool the fresh water entering the heat exchanger.

[0021] The fresh water cooled by the iCER system plate heat exchanger 5 enters the iCER low-temperature fresh water cooling system user 19 to cool the related system and equipment.

[0022] The fresh water cooled by the central plate heat exchanger 6 first passes through the low-temperature fresh water cooling system three-way temperature control valve 7, mixes with the high-temperature fresh water returned after passing through the low-temperature fresh water cooling system user 18, and is transferred to the low-temperature fresh water cooling system user 18 by the low-temperature fresh water transfer pump 8 to cool the related system and equipment.

[0023] The seawater pump frequency conversion control system control box 17 controls the motor rotating speed of the seawater pump 4 by collecting signals of various sensors arranged on the system and the three-way temperature control valve, so as to control the start and stop of the seawater pump and the seawater flow, and to reduce the motor power of the seawater pump and save energy under the premise of meeting the normal operation of the cooling system.

[0024] The seawater pump frequency conversion control system control box 17 has three control modes, i.e. automatic frequency conversion mode, manual frequency conversion mode and fixed frequency mode. The automatic frequency conversion mode is that the seawater pump frequency conversion control system operates autonomously and controls the operation of the seawater pump according to the set control logic. The manual frequency conversion mode needs the crew to manually control the motor rotating speed of the seawater pump. The fixed frequency mode is that when the seawater pump frequency conversion system fails, the seawater pump will automatically switch to fixed frequency and operate at the set maximum rated rotating speed, so as not to affect the operation of the cooling system, and the energy saving effect will not be considered at this time.

[0025] At the same time, since the seawater pump is prone to damage due to long-term operation in low rotating speed mode, the minimum rotating speed of the seawater pump frequency conversion is set, which is generally 60% of the maximum rated rotating speed.

[0026] The seawater pump inlet and outlet differential pressure sensor 16 is installed at the inlet and outlet of the seawater pump 4 to monitor the pressure difference between the inlet and outlet of the seawater pump. When the pressure difference is too small and less than or equal to 0.02 Mpa, it indicates that the seawater pump is faulty, and the seawater pump frequency conversion control system control box 17 will automatically start the standby seawater pump to ensure the normal operation of the cooling water system.

[0027] The temperature sensor 14 and the pressure sensor 15 are installed at the low-temperature seawater inlet of the central plate heat exchanger. When the seawater pressure is too low and less than or equal to 0.02 Mpa, it indicates that the seawater pump and the seawater system are faulty, and a low pressure alarm will be issued, and the crew needs to check the related equipment, valves, filters, etc.

[0028] In the design of the low-temperature fresh water cooling system, the maximum design temperature of seawater entering the central plate heat exchanger is 32℃, and the temperature sensor 14 installed at the low-temperature seawater inlet monitors the seawater temperature. When the temperature exceeds 32℃, a high temperature alarm will be issued, and the crew needs to check the related equipment, valves, filters, etc. and intervene manually.

[0029] The temperature sensor 13 is installed at the low-temperature seawater outlet of the central plate heat exchanger. By comparing the temperature difference between the inlet and outlet of the central plate heat exchanger, when the temperature difference is too large and exceeds the design temperature difference of the central plate heat exchanger, which is generally 12℃~16℃, it indicates that the seawater flow is insufficient, and the frequency conversion control system will increase the flow of the seawater pump, and if necessary, start the standby pump to run simultaneously to ensure the normal operation of the cooling water system, and an alarm will also be issued to prompt the crew to check the related system.

[0030] A temperature sensor 9 is installed at the low-temperature fresh water outlet of the central plate heat exchanger to monitor the temperature of the low-temperature fresh water after being cooled by the central plate heat exchanger and mixed with the returned high-temperature fresh water. According to the requirements of WinGD, the set temperature of the three-way temperature control valve of the low-temperature fresh water cooling system is 25°C. When the temperature of the low-temperature fresh water outlet of the central plate heat exchanger is higher than 25°C, the three-way temperature control valve will try to reduce the temperature by adjusting the mixing ratio. When the sea water temperature is higher than 20°C, the low-temperature fresh water cooled by the central plate heat exchanger is already higher than 25°C, and the three-way temperature control valve will be fully adjusted to the low-temperature fresh water outlet side of the central plate heat exchanger and no longer mix the returned high-temperature fresh water.

[0031] The sea water frequency conversion system will set the control logic. When the temperature of the low-temperature sea water inlet of the central plate heat exchanger is higher than 20°C, the temperature difference between the low-temperature fresh water outlet of the central plate heat exchanger and the low-temperature sea water inlet of the central plate heat exchanger is set to 5°C. When the temperature difference is greater than 5°C, the sea water frequency conversion system will increase the speed of the sea water pump to increase the amount of cooled sea water. If the requirement is still not met, the standby sea water pump will be further started, and an alarm will be sent.

[0032] When the temperature difference is less than 5°C, the sea water frequency conversion system will reduce the speed of the sea water pump to reduce the amount of cooled sea water until the temperature difference stabilizes at 5°C or reaches the minimum speed set for the sea water pump, thereby achieving the purpose of saving energy.

[0033] When the temperature of the low-temperature sea water inlet of the central plate heat exchanger is lower than 20°C, the sea water frequency conversion system will not consider the temperature difference between the low-temperature fresh water outlet of the central plate heat exchanger and the low-temperature sea water inlet of the central plate heat exchanger, but only focus on the temperature of the low-temperature fresh water outlet of the central plate heat exchanger. When the temperature is higher than 25°C, the sea water frequency conversion system will reduce the speed of the sea water pump to reduce the amount of cooled sea water until the temperature stabilizes at 25°C or reaches the minimum speed set for the sea water pump, thereby achieving the purpose of saving energy.

[0034] The low-temperature fresh water inlet temperature sensor 10 of the central plate heat exchanger does not participate in the control of the sea water frequency conversion system and only serves as an inlet temperature display function.

[0035] Since the cooling sea water needs to provide cooling sea water for the central plate heat exchanger, and also needs to provide cooling sea water for the iCER system plate heat exchanger. When the sea water temperature is low or the cooling water demand of the low-temperature fresh water system is low, it will cause the central plate heat exchanger to reduce the demand for sea water, and the sea water frequency conversion system will reduce the power of the sea water pump to the minimum value, thereby causing the amount of sea water entering the iCER system plate heat exchanger to decrease, and when the iCER system plate heat exchanger cannot meet the demand for sea water, it will affect the operation of the iCER system. Therefore, temperature sensors 11, 12 are added at the inlet and outlet of the iCER system plate heat exchanger, and when the temperature difference between the outlet and the inlet is too large, generally 12~16℃, the sea water pump frequency conversion system will increase the speed of the sea water pump until the temperature difference reaches a reasonable range.

Claims

1. A seawater pump variable frequency control system suitable for iCER system, characterized in that, The high-position subsea tank (2) and the low-position subsea tank (1) are connected with the iCER system plate heat exchanger (5) and the central plate heat exchanger (6) through the seawater pump (4) and the seawater main pipe (3); the iCER system plate heat exchanger is connected with the iCER low-temperature fresh water cooling system user (19), and returns to the iCER system plate heat exchanger after connection; the central plate heat exchanger is connected with the low-temperature fresh water cooling system user (18) through the low-temperature fresh water transfer pump (8) and the three-way temperature control valve (7), and returns to the central plate heat exchanger and the three-way temperature control valve after connection; The seawater pump inlet is provided with a seawater pump inlet differential pressure sensor (16), the low-temperature seawater inlet of the central plate heat exchanger is provided with a central plate heat exchanger low-temperature fresh water inlet temperature sensor (10), the low-temperature seawater outlet of the central plate heat exchanger is provided with a central plate heat exchanger low-temperature seawater outlet temperature sensor (13), the low-temperature seawater inlet of the central plate heat exchanger is provided with a central plate heat exchanger low-temperature seawater inlet temperature sensor (14) and a pressure sensor (15), the low-temperature fresh water outlet of the central plate heat exchanger is provided with a central plate heat exchanger low-temperature fresh water outlet temperature sensor (9), the seawater inlet of the iCER system plate heat exchanger is provided with an iCER system plate heat exchanger seawater inlet temperature sensor (12), the seawater outlet of the iCER system plate heat exchanger is provided with an iCER system plate heat exchanger seawater outlet temperature sensor (11), and the seawater pump frequency conversion control system control box (17) is signal-connected with each temperature sensor and pressure sensor.

2. The seawater pump variable frequency control system suitable for the iCER system according to claim 1, characterized in that, The minimum rotating speed of the seawater pump frequency conversion is set to 60% of the maximum rated rotating speed.

3. The sea water pump variable frequency control system suitable for iCER system according to claim 1, characterized in that, There are two seawater pumps, one of which is a standby seawater pump; when the seawater pressure detected by the differential pressure sensor of the seawater pump inlet is less than or equal to 0.02 Mpa, the seawater pump frequency conversion control system control box automatically starts the standby seawater pump.

4. The sea water pump variable frequency control system suitable for iCER system according to claim 1, characterized in that, The highest temperature of seawater entering the central plate heat exchanger is 32℃.

5. The sea water pump variable frequency control system suitable for iCER system according to claim 1, characterized in that, The temperature difference of the central plate heat exchanger is 12℃-16℃.

6. The sea water pump variable frequency control system suitable for iCER system according to claim 1, characterized in that, The set temperature of the three-way temperature control valve is 25℃.

7. The sea water pump variable frequency control system suitable for iCER system according to claim 1, characterized in that, The temperature difference between the central plate heat exchanger low-temperature fresh water outlet temperature and the central plate heat exchanger low-temperature seawater inlet temperature is set to 5℃.