Seawater frequency conversion system suitable for iCER host

Abstract

A seawater frequency conversion system suitable for an iCER main machine is characterized in that a high-position sea chest and a low-position sea chest are respectively connected with an iCER system plate heat exchanger and a central plate heat exchanger through a seawater main pipe, and the high-position sea chest and the low-position sea chest are respectively provided with a seawater pump; and after sequentially entering an iCER system flue gas cooler and an iCER system fresh water circulating water cabinet through a pipeline, returning to the central plate heat exchanger through an iCER low-temperature fresh water lightering pump. A first temperature sensor is arranged at a smoke outlet of an iCER system smoke cooler and used for monitoring the actual temperature T2 of smoke exhaust gas of a host, a host iCER system control box collects the T2, the T2 is sent to a seawater pump frequency conversion control box after being collected, and the seawater pump frequency conversion control box compares the T2 with the required smoke exhaust temperature T1 and controls the conveying frequency of a seawater pump. According to the seawater frequency conversion system control method, normal operation of the low-temperature fresh water cooling system and the iCER system of the ship can be guaranteed at the same time, and the power of the seawater pump can be reduced to the maximum extent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of ship operation design, and particularly relates to a seawater frequency conversion system suitable for iCER main engine. BACKGROUND

[0002] The conventional seawater frequency conversion system control method mainly ensures that the fresh water temperature meets the premise of normal operation of the cooling water system of the ship main engine and auxiliary engine, and tries to reduce the power of the seawater pump to achieve the purpose of energy saving according to the fresh water outlet temperature of the central plate cooler and through certain judgment conditions. However, when the WinGD iCER main engine is used in the ship system, the seawater pump needs to provide seawater not only for the main engine and auxiliary engine, but also for the cooler of the iCER system. The cooling water system commonly used before with WinGD iCER adopts two processing methods. One is to provide a separate seawater pump for the plate cooler of the iCER system, and the seawater pump is in a fixed frequency mode, that is, the frequency of the seawater pump does not change according to the seawater quantity required by the iCER system, so that the iCER system needs to control the seawater flow through the flow regulating valve. This method wastes part of the energy of the iCER system seawater pump. The other method is to provide cooling seawater for the main engine, auxiliary engine and iCER system through the seawater pump, and the seawater pump is a variable frequency pump. The seawater frequency conversion system mainly controls the frequency of the seawater pump according to the fresh water outlet temperature of the central plate heat exchanger, and monitors the fresh water outlet temperature of the iCER cooler to assist in controlling the frequency of the seawater pump. This method is complex in logic, and does not consider the real key temperature setting of the iCER system, that is, the exhaust gas outlet temperature of the iCER flue gas cooler. This temperature is the key node for stable operation of the iCER system and energy saving.

[0003] Therefore, it is necessary to design a new seawater frequency conversion system control method for iCER main engine, which can perform frequency conversion control on the cooling system of the ship with WinGD iCER main engine. SUMMARY

[0004] For the complex cooling system with WinGD iCER main engine and seawater frequency conversion, a seawater frequency conversion system control method is designed, which can ensure the normal operation of the ship low-temperature fresh water cooling system and the iCER system, and can also reduce the power of the seawater pump to the greatest extent. The technical scheme adopted by the method is: A seawater frequency conversion system suitable for iCER host, including iCER system plate heat exchanger and central plate heat exchanger, high submarine valve box, low submarine valve box is connected with iCER system plate heat exchanger, central plate heat exchanger respectively through seawater main pipe, high submarine valve box, low submarine valve box is equipped with seawater pump, seawater is heated in plate heat exchanger, enters iCER system flue gas cooler, iCER system fresh water circulating water tank in turn through pipeline after that, returns to central plate heat exchanger by iCER low temperature fresh water barge pump.

[0005] Central plate heat exchanger is connected with low temperature fresh water cooling system user after passing through iCER low temperature fresh water barge pump, and returns to central plate heat exchanger, the passageway of low temperature fresh water cooling system user to central plate heat exchanger is provided with the fourth temperature sensor, and the passageway of central plate heat exchanger to low temperature fresh water cooling system user is provided with the fifth temperature sensor.

[0006] The flue gas outlet of iCER system flue gas cooler is provided with the first temperature sensor, the actual temperature T2 of host exhaust gas after washing and cooling is monitored, the host iCER system control box collects T2, and sends to seawater pump frequency conversion control box after collection, and seawater pump frequency conversion control box compares T2 with required exhaust temperature T1.

[0007] When T2 is higher than T1, seawater pump frequency conversion control box sends instruction to seawater pump, increases seawater pump frequency, and increases seawater flow.

[0008] When T2 is lower than T1, seawater pump frequency conversion control box sends instruction to seawater pump, reduces seawater pump frequency, and reduces seawater flow.

[0009] The above-mentioned seawater frequency conversion system suitable for iCER host, further, the central plate heat exchanger has two, and the two central plate heat exchangers are connected with iCER low temperature fresh water barge pump through three-way temperature control valve.

[0010] The above-mentioned seawater frequency conversion system suitable for iCER host, further, the seawater outlet of central plate heat exchanger is provided with the second temperature sensor, and when seawater temperature exceeds 50 DEG C, the second temperature sensor sends alarm signal.

[0011] The above-mentioned seawater frequency conversion system suitable for iCER host, further, the third sensor is arranged at the low temperature seawater outlet of plate heat exchanger.

[0012] The above-mentioned seawater frequency conversion system suitable for iCER host, further, the seawater temperature sensor and seawater pressure difference sensor are arranged at the outlet of seawater pump.

[0013] The seawater frequency conversion system suitable for the iCER host further has a seawater temperature sensor and a pressure sensor arranged at the low-temperature seawater inlet of the plate heat exchanger.

[0014] The application considers the strict requirement of the iCER system on the exhaust gas temperature, takes the exhaust gas temperature as a key factor of control, and guarantees that the seawater frequency conversion under the control of the method can meet the requirement of the host, while taking into account the design requirements of the fresh water cooling system of the host and auxiliary machine and the iCER system, and under the condition that the central fresh water cooling system and the iCER system are normally operated, the power of the seawater pump is reduced as much as possible to achieve the purpose of energy saving, 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 operation of the ship is reduced, the level of automatic operation of the ship is provided, and the ship operation is more stable and safe. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a system schematic diagram of the application; Among them, 1-low seabed box, 2-high seabed box, 3-seawater main pipe, 4-seawater pump, 5-iCER system plate heat exchanger, 6-central plate heat exchanger, 7-three-way temperature control valve, 8-iCER low-temperature fresh water transfer pump, 9-fifth temperature sensor, 10-fourth temperature sensor, 11-first temperature sensor, 12-second temperature sensor, 13-third temperature sensor, 14-seawater temperature sensor, 15-pressure sensor, 16-pressure difference sensor, 17-seawater pump frequency conversion control box, 18-low-temperature fresh water cooling system user, 19-iCER low-temperature fresh water transfer pump, 20-host iCER system control box, 21-iCER system flue gas cooler, 22-iCER system fresh water circulating water tank. DETAILED DESCRIPTION

[0016] The application is further described in combination with the drawings.

[0017] A seawater frequency conversion system suitable for an iCER host, seawater enters a seawater main pipe 3 through high and low seabed boxes 1 and 2, and a seawater pump 4 transfers the seawater to an iCER system plate heat exchanger 5 and a central plate heat exchanger 6 to cool fresh water entering the plate heat exchangers.

[0018] The fresh water cooled by the iCER system plate heat exchanger 5 enters an iCER system flue gas cooler 21 to wash and cool the host exhaust gas entering the flue gas cooler, clean the flue gas while reducing the flue gas temperature, and the cooled host exhaust gas is discharged from the iCER system flue gas cooler through a flue gas outlet to return to a host booster to participate in combustion.

[0019] The seawater frequency conversion system control method of the main engine cooling system is a conventional WinGD main engine seawater frequency conversion system control method. The fresh water cooled by the central plate heat exchanger 6 is first mixed with the high-temperature fresh water returned after passing through the low-temperature fresh water cooling system user 18 after passing through the low-temperature fresh water cooling system three-way temperature control valve 7, and then is transported to the low-temperature fresh water cooling system user 18 by the low-temperature fresh water transport pump 8 to cool the related systems and equipment.

[0020] The system is provided with a seawater pump inlet and outlet pressure difference sensor 16 for monitoring the inlet and outlet pressure difference of the seawater pump, a temperature sensor 14 and a pressure sensor 15 are installed at the low-temperature seawater inlet of the central plate heat exchanger for monitoring the seawater temperature and pressure. A temperature sensor 13 is installed at the low-temperature seawater outlet of the central plate heat exchanger for monitoring the seawater outlet temperature of the central plate heat exchanger. A temperature sensor 20 is installed after the low-temperature fresh water cooling system three-way temperature control valve 7 for monitoring the temperature of the mixed water after being cooled by the central plate heat exchanger and returned with the high-temperature fresh water, and the three-way temperature control valve is set to 25°C. The low-temperature fresh water inlet of the central plate heat exchanger is provided with a temperature sensor 10 for displaying the return water temperature.

[0021] The seawater pump frequency conversion control box 17 collects signals from various sensors and three-way temperature control valves arranged in the system to output instructions to reduce or increase the pump frequency of the seawater pump 4.

[0022] The seawater frequency conversion control method of the iCER system is as follows: The seawater pump 4 transports seawater to the iCER system plate heat exchanger 5 for cooling the fresh water of the iCER system, and the cooled fresh water is transported to the iCER system flue gas cooler 21 for washing and cooling the exhaust gas of the main engine, and the washed and cooled exhaust gas of the main engine is discharged through the flue gas outlet. The temperature of the cooled water increases by gravity and enters the iCER system fresh water circulating tank 22, and then is transported to the iCER system plate heat exchanger by the iCER low-temperature fresh water transport pump 19 for cooling, which is used for the next flue gas washing and cooling.

[0023] A temperature sensor 11 is installed at the seawater outlet of the iCER system plate heat exchanger for monitoring the temperature of the seawater at the side of the ship, and an alarm signal will be sent out when the seawater temperature exceeds 50°C to remind the crew to check the related equipment.

[0024] The temperature sensor 12 is installed at the flue gas outlet of the iCER system flue gas cooler to monitor the temperature of the main engine exhaust gas after washing and cooling. Since the main engine exhaust gas after washing and cooling needs to return to the main engine booster for further main engine combustion, the temperature is a key factor for the normal operation of the iCER system. If the flue gas temperature returning to the main engine is too high, the purpose of cooling the combustion air cannot be achieved, resulting in high combustion temperature, insufficient combustion of main engine fuel or gas, increased NOX content, and even stopping of the iCER system, which cannot meet the Tier III emission requirements, and increased main engine fuel consumption. Therefore, the main engine has strict requirements for the flue gas temperature, which is adjusted according to different operating conditions and emission conditions of the main engine, and is not a fixed set temperature. Therefore, the iCER system control box 20 needs to collect the iCER system flue gas cooler flue gas outlet temperature sensor signal, and output the main engine required flue gas temperature T1 and the actual flue gas temperature T2 to the seawater pump frequency control box 17. The seawater frequency conversion system compares T1 and T2: When the actual flue gas temperature T2 is higher than the main engine required flue gas temperature T1, the frequency conversion system needs to increase the frequency of the seawater pump 4 to increase the seawater flow and reduce the fresh water temperature, so as to finally achieve the purpose of reducing the actual flue gas temperature T2 to T1.

[0025] When the actual flue gas temperature T2 is lower than the main engine required flue gas temperature T1, the frequency conversion system needs to reduce the frequency of the seawater pump 4 to reduce the seawater flow until T2 equals T1, so as to achieve the purpose of saving energy of the seawater pump.

[0026] Since the main engine cooling system and the iCER system have their own seawater frequency control methods, but share the same seawater pump, it is necessary to ensure that the flow of the seawater pump can meet the needs of both cooling systems.

[0027] When the main engine cooling system needs to increase the frequency of the seawater pump, and the iCER system needs to reduce or maintain the frequency of the seawater pump, the seawater pump frequency control box 17 needs to increase the frequency of the seawater pump according to the requirements of the main engine cooling system until the requirements of the main engine cooling system are met.

[0028] When the main engine cooling system needs to reduce or maintain the frequency of the seawater pump, and the iCER system needs to increase the frequency of the seawater pump, the seawater pump frequency control box 17 needs to increase the frequency of the seawater pump according to the requirements of the iCER system until the requirements of the iCER system are met.

[0029] When the main engine cooling system needs to reduce the frequency of the seawater pump, and the iCER system also needs to reduce the frequency of the seawater pump, the seawater pump frequency control box 17 needs to reduce the frequency of the seawater pump until either the main engine cooling system or the iCER system meets the requirement of maintaining the frequency of the seawater pump.

Claims

1. A seawater frequency conversion system suitable for iCER mainframes, characterized in that, It includes the iCER system plate heat exchanger and the central plate heat exchanger. The high-level seabed valve box and the low-level seabed valve box are connected to the iCER system plate heat exchanger and the central plate heat exchanger respectively through the seawater main pipe. Both the high-level seabed valve box and the low-level seabed valve box are equipped with seawater pumps. After the seawater is heat-exchanged in the plate heat exchanger, it enters the iCER system flue gas cooler and the iCER system freshwater circulating tank through the pipeline in sequence, and then returns to the central plate heat exchanger through the iCER low temperature freshwater transfer pump. After the central plate heat exchanger is connected to the user of the low-temperature freshwater cooling system via the iCER low-temperature freshwater transfer pump, it returns to the central plate heat exchanger. A fourth temperature sensor is installed on the path from the user of the low-temperature freshwater cooling system to the central plate heat exchanger, and a fifth temperature sensor is installed on the path from the central plate heat exchanger to the user of the low-temperature freshwater cooling system. The flue gas outlet of the iCER system flue gas cooler is equipped with a first temperature sensor to monitor the actual temperature T2 of the exhaust gas from the main unit after washing and cooling. The main unit iCER system control box collects T2 and sends it to the seawater pump frequency converter control box. The seawater pump frequency converter control box compares T2 with the required exhaust gas temperature T1. When T2 is higher than T1, the seawater pump frequency converter control box sends a command to the seawater pump to increase the seawater pump frequency and increase the seawater flow rate. When T2 is lower than T1, the seawater pump frequency converter control box sends a command to the seawater pump to reduce the seawater pump frequency and reduce the seawater flow.

2. The seawater frequency conversion system suitable for iCER mainframes according to claim 1, characterized in that, There are two central plate heat exchangers, which are connected to the iCER cryogenic freshwater transfer pump via a three-way thermostatic valve.

3. A seawater frequency conversion system suitable for iCER mainframes according to claim 1, characterized in that, The seawater outlet of the central plate heat exchanger is equipped with a second temperature sensor. When the seawater temperature exceeds 50°C, the second temperature sensor will send an alarm signal.

4. A seawater frequency conversion system suitable for iCER mainframes according to claim 1, characterized in that, A third sensor is installed at the low-temperature seawater outlet of the plate heat exchanger.

5. A seawater frequency conversion system suitable for iCER mainframes according to claim 1, characterized in that, The seawater pump outlet is equipped with a seawater temperature sensor and a seawater differential pressure sensor.

6. A seawater frequency conversion system suitable for iCER mainframes according to claim 1, characterized in that, The plate heat exchanger is equipped with a seawater temperature sensor and a pressure sensor at the low-temperature seawater inlet.

Images