Ship cold end system with ballast water and self-flowing water running alternately and regulation and control method

Abstract

The invention relates to a ship cold end system with ballast water and self-flowing water running alternately and a regulation and control method, and belongs to the field of ship cooling and ballast water heat treatment, the ship cold end system with ballast water and self-flowing water running alternately comprises a steam-condensed water circulation, an environmental water circulation for cooling steam turbine dead steam and a ballast water circulation, the ballast water and the environmental water flow together on the pipe side of the shell-and-tube condenser; ballast water and environmental water alternately flow into the circulating water pump through two three-way valves, and the ballast water circulation is externally connected with a ballast water treatment controller. When a ballast water treatment instruction is received, self-flowing water is cut off, ballast water is communicated to a condenser, and primary heating of the ballast water is achieved while dead steam is condensed; the ballast water is further heated through steam extraction of a steam turbine, and the temperature of the ballast water is automatically controlled to be kept between the upper limit and the lower limit; the ballast water heat treatment energy consumption can be effectively reduced, and automatic switching between ballast water and self-flowing water is achieved through control over the pressure of the condenser, the rotating speed of the circulating water pump and the three-way valve.

Description

Technical Field

[0001] This invention belongs to the field of ship cooling and ballast water heat treatment, and relates to a ship cold end system and control method with alternating operation of ballast water and gravity flow water. Background Technology

[0002] With the continuous development of society and the economy, global attention to energy conservation, emission reduction, and green development is increasing, and the shipbuilding industry is no exception. Under this major trend, "green shipping" has become a key direction for the development of the shipbuilding industry. For modern ships, they should develop towards environmentally friendly green ships, which requires ships to minimize the consumption of various resources during operation in order to achieve sustainable development goals.

[0003] Against this backdrop, on the one hand, modern ship propulsion systems widely employ gravity-fed water (i.e., ambient water) cooling systems to shut down ambient water circulation pumps or reduce their power consumption. On the other hand, to avoid the potential hazards of direct discharge of ballast water, modern ships generally treat ballast water mechanically, physically, or chemically before discharge. Among these methods, heating is a physical treatment approach, which involves heating the ballast water to a certain temperature, typically 40-50 degrees Celsius, and maintaining it for 2-4 hours. This can kill most organisms, but it suffers from problems such as long treatment time and excessive energy consumption. Summary of the Invention

[0004] In view of this, in order to solve the problems of high energy consumption in ballast water heat treatment and insufficient synergy between gravity flow and ballast water treatment, which leads to the inability to effectively utilize the waste heat of the ship's power system and resulting in energy waste, the present invention provides a ship cold end system and control method that alternates between ballast water and gravity flow.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A ship cold-end system with alternating ballast water and gravity-flow water includes a steam-condensate circulation, an ambient water circulation for cooling turbine exhaust steam, and a ballast water circulation. The steam-condensate circulation condenses the gas into water through a shell-and-tube condenser, and then sends it back to the boiler via a condensate pump. Ballast water and ambient water flow together on the tube side of the shell-and-tube condenser. Ballast water and ambient water flow alternately into the circulating water pump through two three-way valves. The ballast water circulation is externally connected to a ballast water treatment controller.

[0007] Furthermore, in the initial state, the ambient water condenses the exhaust steam in the condenser. When the ballast water treatment signal S=1 is issued by the ballast water treatment controller, the two three-way valves close to their minimum position, cutting off the ambient water circulation and connecting the ballast water circulation. At the same time, the circulating water pump is started to realize ballast water circulation, and the ballast water is sent to the condenser, condensing the exhaust steam while simultaneously achieving preliminary heating of the ballast water. When the circulating water pump speed n equals the maximum speed n... maxAt this time, the ballast water treatment signal S=0, and the two three-way valves open to the maximum, cutting off the ballast water circulation and connecting the ambient water circulation, thus ending the initial heating of the ballast water.

[0008] Furthermore, when the ballast water treatment signal S=1 is sent by the ballast water treatment controller, the circulating water pump is started, and when the pressure P inside the condenser... 凝 Greater than the set value P 凝设 At that time, the speed n of the ambient water circulating pump is adjusted by the PID controller. 环水 This, in turn, regulates the ballast water flow rate.

[0009] Furthermore, the ballast water circulation includes extraction valves for controlling the low-pressure extraction of steam from the turbine, a shell-and-tube heat exchanger, and a ballast water pump. The latent heat of the extracted steam condensation is transferred to the ballast water through the heat exchanger. The ballast water temperature is raised to the upper limit T1 and then stopped. At the same time, the condensate from the extracted steam condensation is discharged to the condenser.

[0010] Furthermore, the ballast water circulation specifically involves: ballast water temperature T 压载水 When the ballast water temperature is below the lower limit T2, the ballast water pump starts and the steam extraction valve opens; when the ballast water temperature T... 压载水 When the ballast water temperature reaches the upper limit T1, the ballast water pump is shut off and the steam extraction valve is closed; this process is repeated to control the ballast water temperature within the range of T2 to T1.

[0011] A method for regulating a ship's cold-end system that alternates between ballast water and gravity-flow water, specifically including:

[0012] Gravity flow and ballast water mode switching control: In the initial state, exhaust steam is condensed in the condenser using ambient water. When the ballast water treatment signal S=1 is issued by the ballast water treatment controller, both three-way valves close to their minimum position, cutting off the ambient water circulation and connecting the ballast water circulation, allowing ballast water to flow to the condenser; when the circulating water pump speed n equals the maximum speed n... max When the ballast water treatment signal S=0, the two three-way valves open upwards to their maximum, cutting off the ballast water circulation and connecting the ambient water circulation;

[0013] Primary heating control: When the ballast water treatment signal S=1 is sent by the ballast water treatment controller, the ballast water circulation is activated, and the ballast water is sent to the condenser, simultaneously condensing the exhaust steam and achieving preliminary heating of the ballast water; when the pressure P inside the condenser... 凝 Greater than the set value P 凝设 At that time, the speed n of the ambient water circulating pump is adjusted by the PID controller. When the speed n of the circulating pump is equal to the maximum speed n... max At that time, the initial heating of the ballast water was completed;

[0014] Secondary heating control: When the ballast water temperature T 压载水When the temperature is below the lower limit of the ballast water temperature T2, the ballast water pump is turned on and the extraction steam valve is opened. The latent heat of the extraction steam condensation is transferred to the ballast water through the heat exchanger. The ballast water temperature is raised to the upper limit of the ballast water temperature T1 and then stopped. At the same time, the condensate from the extraction steam condensation is discharged to the condenser.

[0015] Temperature control: When the ballast water temperature T 压载水 When the ballast water temperature reaches the upper limit T1, the ballast water pump is shut off and the steam extraction valve is closed; this process is repeated to control the ballast water temperature within the range of T2 to T1, forming a periodic temperature control cycle, so that the ballast water temperature is within the range of 40~50 degrees Celsius, ensuring the biological inactivation effect.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. The ship cold end system disclosed in this invention, which alternates between ballast water and gravity flow, operates alternately. During normal operation, gravity flow condenses exhaust steam in the condenser. Upon receiving a ballast water treatment command, the gravity flow is cut off, and ballast water is connected to the condenser, simultaneously condensing exhaust steam and achieving initial heating of the ballast water. After initial heating, the ballast water is cut off again, and gravity flow is connected to the condenser. Following this initial heating, steam is extracted from a steam turbine to further heat the ballast water, and the ballast water temperature is automatically controlled to remain between upper and lower limits. This effectively reduces the energy consumption for ballast water heat treatment.

[0018] 2. The ship cold end system with alternating operation of ballast water and gravity flow disclosed in this invention achieves automatic switching between ballast water and gravity flow through condenser pressure, circulating water pump speed control, and three-way valve control, solving the problem of insufficient synergy between gravity flow and ballast water treatment, and effectively utilizing the waste heat of the ship's power system.

[0019] 3. The ship cold end system with alternating operation of ballast water and gravity flow disclosed in this invention controls the ballast water temperature within the range of T2 to T1 through ballast water pumps and steam extraction valves, thereby maintaining the ballast water temperature within the upper and lower limits and effectively killing organisms in the ballast water.

[0020] 4. The ship cold end system with alternating operation of ballast water and gravity flow disclosed in this invention issues a ballast water treatment command when the ship is at high speed. Because the exhaust steam volume is large at high speed, the cooling capacity is insufficient, the condenser vacuum is low, and the exhaust steam pressure is high, it is beneficial to obtain a higher ballast water temperature rise.

[0021] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0022] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram of the structure of a ship cold-end system that alternates between ballast water and gravity-flow water according to the present invention;

[0024] Figure 2 This is a schematic diagram of the alternating operation control of ballast water and gravity-flow water in the present invention;

[0025] Figure 3 This is a schematic diagram showing the control of the circulating water pump speed and flow rate when ballast water is introduced in this invention;

[0026] Figure 4 This is a schematic diagram of the ballast water further heat exchange and temperature rise structure in this invention;

[0027] Figure 5 This is a schematic diagram of the staged heat exchange and temperature rise control of ballast water in this invention. Detailed Implementation

[0028] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] like Figure 1 The illustrated cold-end system of a ship, in which ballast water and gravity-flow water alternate, includes a steam-condensate circulation, an ambient water circulation for cooling turbine exhaust steam, and a ballast water circulation. The steam-condensate circulation condenses the gas into water through a shell-and-tube condenser, and then sends it back to the boiler via a condensate pump. Ballast water and ambient water flow together on the tube side of the shell-and-tube condenser. Ballast water and ambient water flow alternately into the circulating water pump through two three-way valves.

[0030] Reference Figure 2 As shown, in the initial state, ambient water condenses exhaust steam in the condenser. When the ballast water treatment signal S=1 is sent by the ballast water treatment controller, the two three-way valves close to their minimum position, cutting off the ambient water circulation and connecting the ballast water circulation. At the same time, the circulating water pump is turned on to realize ballast water circulation, and the ballast water is sent to the condenser, condensing exhaust steam while simultaneously achieving preliminary heating of the ballast water; when the circulating water pump speed n equals the maximum speed n... maxAt this time, the ballast water treatment signal S=0, and the two three-way valves open to the maximum, cutting off the ballast water circulation and connecting the ambient water circulation, thus ending the initial heating of the ballast water.

[0031] Reference Figure 3 As shown, when ballast water is introduced (i.e., ballast water treatment signal S=1), the circulating water pump is started, and when the pressure P in the condenser... 凝 Greater than the set value P 凝设 At that time, the speed n of the ambient water circulating pump is adjusted by the PID controller. 环水 This allows for the adjustment of ballast water flow to maintain the condenser pressure at P. 凝设 In actual operation, the circulating water pump speed n and flow rate gradually increase. The circulating water pump speed n is used to trigger the opening of the three-way valve for the alternating operation control of ballast water and gravity flow (e.g., Figure 2 As shown in the figure, when the circulating water pump speed n=n max The ballast water circulation is cut off at the appropriate time, and the initial heating of the ballast water ends.

[0032] Reference Figure 4 Ballast water circulation includes extraction valves for controlling low-pressure extraction of steam from the turbine, shell-and-tube heat exchangers, and ballast water pumps. The latent heat of the extracted steam condensation is transferred to the ballast water through the heat exchanger. The ballast water temperature is raised to the upper limit T1 and then stopped. At the same time, the condensate from the extracted steam condensation is discharged to the condenser.

[0033] Reference Figure 5 During ballast water heating treatment, the ballast water temperature needs to be maintained within a certain range, such as 40-50 degrees Celsius, for an extended period to effectively kill organisms in the ballast water. When the ballast water temperature T... 压载水 When the ballast water temperature is below the lower limit T2, the ballast water pump starts and the steam extraction valve opens; when the ballast water temperature T... 压载水 When the ballast water temperature reaches the upper limit T1, the ballast water pump is shut off and the steam extraction valve is closed; this process is repeated to control the ballast water temperature within the range of T2 to T1.

[0034] A method for regulating a ship's cold-end system that alternates between ballast water and gravity-flow water, specifically including:

[0035] Gravity flow and ballast water mode switching control: In the initial state, exhaust steam is condensed in the condenser using ambient water. When the ballast water treatment signal S=1 is issued by the ballast water treatment controller, both three-way valves close to their minimum position, cutting off the ambient water circulation and connecting the ballast water circulation, allowing ballast water to flow to the condenser; when the circulating water pump speed n equals the maximum speed n... max When the ballast water treatment signal S=0, the two three-way valves open upwards to their maximum, cutting off the ballast water circulation and connecting the ambient water circulation;

[0036] Primary heating control: When the ballast water treatment signal S=1 is sent by the ballast water treatment controller, the ballast water circulation is activated, and the ballast water is sent to the condenser, simultaneously condensing the exhaust steam and achieving preliminary heating of the ballast water; when the pressure P inside the condenser... 凝 Greater than the set value P 凝设 At that time, the speed n of the ambient water circulating pump is adjusted by the PID controller. When the speed n of the circulating pump is equal to the maximum speed n... max At that time, the initial heating of the ballast water was completed;

[0037] Secondary heating control: When the ballast water temperature T 压载水 When the temperature is below the lower limit of the ballast water temperature T2, the ballast water pump is turned on and the extraction steam valve is opened. The latent heat of the extraction steam condensation is transferred to the ballast water through the heat exchanger. The ballast water temperature is raised to the upper limit of the ballast water temperature T1 and then stopped. At the same time, the condensate from the extraction steam condensation is discharged to the condenser.

[0038] Temperature control: When the ballast water temperature T 压载水 When the ballast water temperature reaches the upper limit T1, the ballast water pump is shut off and the steam extraction valve is closed; this process is repeated to control the ballast water temperature within the range of T2 to T1, forming a periodic temperature control cycle, so that the ballast water temperature is within the range of 40~50 degrees Celsius, ensuring the biological inactivation effect.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A ship cold-end system with alternating operation of ballast water and gravity-flow water, characterized in that, It includes a steam-condensate circulation, an ambient water circulation for cooling turbine exhaust steam, and a ballast water circulation. The steam-condensate circulation condenses the overflow gas into water through a shell-and-tube condenser, and then sends it back to the boiler via a condensate pump. The ballast water and ambient water flow together on the tube side of the shell-and-tube condenser. The ballast water and ambient water flow alternately into the circulating water pump through two three-way valves. The ballast water circulation is externally connected to a ballast water treatment controller.

2. The ship cold end system as described in claim 1, characterized in that, Initially, ambient water condenses exhaust steam in the condenser. When the ballast water treatment controller sends a ballast water treatment signal S=1, both three-way valves close to their minimum position, cutting off the ambient water circulation and connecting the ballast water circulation. Simultaneously, the circulating water pump starts to circulate the ballast water, which then flows to the condenser, condensing the exhaust steam while simultaneously providing initial heating to the ballast water. When the circulating water pump speed n equals the maximum speed n... max At this time, the ballast water treatment signal S=0, and the two three-way valves open to the maximum, cutting off the ballast water circulation and connecting the ambient water circulation, thus ending the initial heating of the ballast water.

3. The ship cold end system as described in claim 2, characterized in that, When the ballast water treatment signal S=1 is sent by the ballast water treatment controller, the circulating water pump is started, and when the pressure P inside the condenser... 凝 Greater than the set value P 凝设 At that time, the speed n of the ambient water circulating pump is adjusted by the PID controller. 环水 This, in turn, regulates the ballast water flow rate.

4. The ship cold end system as described in claim 1, characterized in that, The ballast water circulation includes extraction valves for controlling the low-pressure extraction of steam from the turbine, a shell-and-tube heat exchanger, and a ballast water pump. The latent heat of the extracted steam condensation is transferred to the ballast water through the heat exchanger. The ballast water temperature is raised to the upper limit T1 and then stopped. At the same time, the condensate from the extracted steam condensation is discharged to the condenser.

5. The ship cold end system as described in claim 4, characterized in that, The ballast water circulation specifically involves: ballast water temperature T 压载水 When the ballast water temperature is below the lower limit T2, the ballast water pump starts and the steam extraction valve opens; when the ballast water temperature T... 压载水 When the ballast water temperature reaches the upper limit T1, the ballast water pump is shut off and the steam extraction valve is closed; this process is repeated to control the ballast water temperature within the range of T2 to T1.

6. A method for regulating a ship's cold-end system that alternates between ballast water and gravity-flow water, characterized in that, Specifically, it includes: Gravity flow and ballast water mode switching control: In the initial state, exhaust steam is condensed in the condenser using ambient water. When the ballast water treatment signal S=1 is issued by the ballast water treatment controller, both three-way valves close to their minimum position, cutting off the ambient water circulation and connecting the ballast water circulation, allowing ballast water to flow to the condenser; when the circulating water pump speed n equals the maximum speed n... max When the ballast water treatment signal S=0, the two three-way valves open upwards to their maximum, cutting off the ballast water circulation and connecting the ambient water circulation; Primary heating control: When the ballast water treatment signal S=1 is sent by the ballast water treatment controller, the ballast water circulation is activated, and the ballast water is sent to the condenser, simultaneously condensing the exhaust steam and achieving preliminary heating of the ballast water; when the pressure P inside the condenser... 凝 Greater than the set value P 凝设 At that time, the speed n of the ambient water circulating pump is adjusted by the PID controller. When the speed n of the circulating pump is equal to the maximum speed n... max At that time, the initial heating of the ballast water was completed; Secondary heating control: When the ballast water temperature T 压载水 When the temperature is below the lower limit of the ballast water temperature T2, the ballast water pump is turned on and the extraction steam valve is opened. The latent heat of the extraction steam condensation is transferred to the ballast water through the heat exchanger. The ballast water temperature is raised to the upper limit of the ballast water temperature T1 and then stopped. At the same time, the condensate from the extraction steam condensation is discharged to the condenser. Temperature control: When the ballast water temperature T 压载水 When the ballast water temperature reaches the upper limit T1, the ballast water pump is shut off and the steam extraction valve is closed; this process is repeated to control the ballast water temperature within the range of T2 to T1. A periodic temperature-controlled circulation is formed to keep the ballast water temperature within the range of 40~50 degrees Celsius, ensuring the effectiveness of biological inactivation.

Images