APPARATUS FOR AUTOMATICALLY MANAGING BALLAST WATER OF SHIP, AND OPERATION METHOD THEREOF

TECHNICAL FIELD

The present invention relates to an apparatus for automatically managing the ballast water of a dual-hulled ship and, more specifically, to an apparatus for automatically managing the ballast water of a ship, the apparatus dividing the structure of an integrated ballast water tank into ballast water tanks of a multi-layered structure, and filling each ballast water tank with seawater, so as to perform the original function thereof of maintaining the water-line by means of the ballast water, and having a structure and a device so as to utilize the seawater, used as cooling water, residential water, water for miscellaneous use, and the like, as the seawater of the ballast water tanks, thereby integrally managing the usage of the seawater of the ship, and continuously and successively changing the seawater of the ballast water tanks while the ship is sailing.

RELATED ART

Since 1993, the shipbuilding industry has been booming in Korea as a requirement for the double hull of the new ship. Since 2005, ships without double hulls have been forcibly removed, but single hull oil tankers still operate in Korea. Because of this, there is a risk of oil spillage from the ship and the insurance premium of the ship is high. In this regard, the market for ballast water management systems also presents new opportunities.

The ballast water management system of the ship is regulated by BWM (ballast water management) Convention under the United Nations' International Maritime Organization (IMO). Korea is also stipulating the Marine Pollution Prevention Act since 2009. The Convention, which is ratified by nations equaling 35% of the world's fleet, is effective 12 months later and has been ratified by 44 nations, 32.86% as of Jan. 30, 2015. In other words, it will be possible that the effective date of the Convention within at least one year. Korea has a legal basis for the Ballast Water Management Act (Ministry of Maritime Affairs and Fisheries Notice No. 2015-37, Apr. 1, 2015) (ballast water line and load line—excerpt from Korean Rules for Classification of Steel Wire, see FIG. 8).

A ship such as a cargo ship cannot be navigated because the center of gravity of the ship is so high that the propeller is not submerged under water when the cargo is not loaded, and there is a high risk that it can be easily overturned by sea waves. Therefore, by lowering the center of gravity of the ship so that the propeller can be submerged under water, it can sail and remain stable. In order to perform this function, the seawater is stored in the ship hull, which is called a ballast water, and an empty space for storing the seawater should be provided. The point at which the ship is fully loaded with cargo is called the design load water line (DLWL) and the point where the propeller is barely submerged under water is called the ballast water line (BWL).

FIG. 9 shows a correlation table between the Deadweight tonnage (Dwt) and an amount of the ballast water of a general ship (Korean Register of Shipping data) and shows the ballast water load of the cargo ships. According to this, the ship should load seawater up to 50 wt % amount of cargo, and the amount of fuel used to load and discharge ballast water occupy about 3 to 5% of the fuel consumption of the ship (according to the data from US Coast Guard). This cost is similar to the net profits of all the shipping companies in Korea, according to the Korea Ship Owners ‘Association’ s annual report published in 2004.

In general, the structure of the ballast water tank used for the double hull cargo ship is shown in FIG. 10. FIG. 10 is a cross-sectional view of the ballast water tank, showing a bottom tank, a hopper side tank, a side tank, and a topside tank.

The devices for supplying ballast water in the ship are specified in detail in FIG. 11 in accordance with the legal regulations. FIG. 11 shows classification rules relating to general ballast equipment.

FIG. 12 is a schematic diagram of a typical ballast tank arrangement.

Commonly used ballast water management methods are classified into three types.

The isolation method is used when the ballast water is so polluted that it is difficult or impossible to purify.

The treatment method is a method in which the ballast water containing living organisms is subjected to various processes such as electrolysis, ultraviolet ray treatment, chemical treatment, plasma treatment, and the like, for killing the living organisms, after which the ballast water is filtered.

The exchange method is mainly used when the contamination of the ship ballast water is not severe or the amount of the water for treatment is small.

FIG. 13 shows the ship ballast water management method recommended by the United Nations Marine Environment Protection Committee (MEPC) under the International Maritime Organization (IMO).

According to the currently used ballast water management system BWMS, the ship generally sails to the destination port with sea water loaded in the ballast water tank and discharges the ballast water for cargo loading. In this process, A large amount of active substance is generated, including transport-prohibited living organisms.

FIG. 14 shows the transport-prohibited life species (extracted from KBS 1TV on Nov. 24, 2004).

The ballast water contains pollutants generated due to the various methods used to kill the 10 transport-prohibited living organisms regulated by UN. The ballast water, the bilge water, the toilet water, the cleaning water, etc. containing contaminants are collectively referred to as the active substance. The MARPOL 73/78 Protocol is an agreement to prevent marine pollution caused by the active substance in marine pollution.

The worldwide harbors are suffering by not only disturbance of the marine ecosystem but also propagation of pathogens, caused by the fact that more than 13 billion tons of ballast water are transported each year and about 7,000 kinds of forbidden marine living organisms are transported across ocean every day between harbors.

For example, the ecosystem disturbance that occurred near Chesapeake Bay in the US seriously damaged the sturgeon shark farm around the bay, causing a damage recovery cost of over US $1 billion per year. It also adversely affected inside the Great Lakes, causing a serious ecosystem disturbance such as the extinction of some native species in the Great Lakes. These events also played an ironic role in bringing about the United Nations Convention on Biological Diversity (UNCCD).

The active substance in a ship must be discharged by exchanging the ballast water at a distance of more than 20 mph from the coast before entry into the destination port, wherein on the open sea of the water depth of 500 m or more, three times of the amount of existing ballast water must be exchanged, through which more than 95% of the prohibited species must be removed.

FIG. 15 shows the Open Sea Emission Regulations (extract from KBS TV).

As described above, the conventionally used ballast water management system BWMS of the ship causes disturbance of the global marine ecosystem due to the transportation of prohibited life species. The energy consumption for ballast water exchange is 3 to 5% of the annual consumption of the ship, which is very costly. The installation and maintenance cost of the processing apparatus for treating the active substances is high. There is a danger that the ship sinks during the ballast water exchange and there is a large economic loss such as a decrease in the number of times of sailings due to the time spent on the open sea for the ballast water exchange.

In addition, due to the structure of the ballast water tank, the structure of the ship is twisted. In order to prevent this problem, the structure of the ballast water tank is strengthened by steel structure, which increases the installation amount of the steel structural member, and this increases the weight of the ship hull structure. For these and other reasons, there were structural and mechanical problems in ship structure.

DETAILED DESCRIPTION OF THE INVENTION
Technical Problem to be Solved

The present invention is devised for improving the drawbacks of the prior art. The conventional ballast water management system is composed as follows.

In ships, seawater is used for various purposes during sailing. In order to use seawater, there is an inlet device (which is called Seachest) for introducing seawater on the bottom or side of the engine room. It is equipped with an open-close unit (valve). When the open-close unit is closed, the watertight structure is formed to prevent the seawater from entering the room. When the open-close unit at the bottom is opened, seawater is introduced by natural pressure, and seawater flows into the ballast water line by the weight of the ship.

Pumps are installed in the machine room or the pump room to cause the flow of seawater. Generally, electrically operated pumps are used. Through the piping (piping and piping accessories) connected to these pumps and the seawater inlet open-close unit, the seawater is sent to the desired locations. Depending on the application of seawater, various pumps such as ballast water pumps, cooling water pumps, fire water pumps, mechanical unit water pumps, residential water pumps, and bilge water pumps, etc. are used.

Depending on the purpose of the seawater, the ballast water management system and the general-purpose seawater management system have been operated in separately.

A ballast water storage tank is provided to store the seawater in the structure of the double hull so as to make gravity force forcing some of the ship to be submerged under water. The ballast water storage tank comprises a bottom tank, a side tank, a hopper side tank, a top side tank, or a wing tank etc. to fill the ballast water. These terms are used to distinguish between top and bottom of the ship when viewed vertically. The terms “bow tanks”, “central tanks” and “stern tanks” are used to distinguish the front and rear of the ship. In ships with double hull structure, most of ballast tanks except for bottom tanks are installed as one single integral tank. When the water of the ballast water tank is discharged, the uppermost space of the ballast water tank becomes empty. When the check valve installed on the upper deck is operated to control the water level of the ballast water tank, ballast water is supplied to fill empty part of the ballast water tank.

In discharging the ballast water for loading cargo, the open-close unit connected to the ballast water tank is opened and the pump is operated to discharge it out of ship, and the discharge pipe is installed on the side of the ship.

Conventional ship ballast water management apparatus includes ballast water contaminated with transport-prohibited living species. This has caused problems, such as marine ecosystem disturbance.

In addition, the ship draws in seawater and uses it for various purposes besides ballast water. Seawater mainly used for machinery is used for engine coolant, generator coolant, main air compressor coolant, stern tube lubricant coolant, boiler coolant, etc. In order to use domestic or residential water such as fire water, cleaning water, kitchen water, shower water etc., seawater is changed to fresh water by using a fresh water generator, and a storage tank for this purpose is also provided. For this reason, seawater continues to flow in and out while the ship is sailing.

Korean Patent No. 10-1206025 “a fresh water treatment system of a ship” discloses a device for desalination process of seawater.

Energy for drawing in seawater for ballast, machinery, and desalination equipment (water purifier) for domestic water consumes about 10% or more of the total energy consumed by the ship.

In general, in order to solve the problem, we must analyze the interaction between the related factors. FIG. 16 is an association chart analyzing the cause of the ecosystem disturbance problem caused by the ballast water.

Through the association analysis of the problem, it was found that the causes are as follows.

One cause is that the inflow of seawater containing transport-prohibited living species.

Another cause is that the transport-prohibited species contained in the inflowed seawater are mutated, grow, or generate other toxic substances during the sailing of the ship, resulting in increased contamination.

Yet another cause is that the ballast water with increased contamination by the transport-prohibited life species during ship sailing is discharged out of ship.

If the solution is derived based on only by eliminating each cause separately, it is difficult to find out the potential cause that is not easy to see, and it is difficult to obtain a fundamental solution. The cause of the interaction between the elements must also be derived.

In the integrated type ballast tank, ballast water is kept isolated during ship sailing. This is yet another cause of the increase of contamination of the ballast water due to mutations of the transfer-prohibited life species or generating of toxic substances, etc.

The best solution deduction method for solving the problem is shown in FIG. 17.

Look for any way that minimize modifications in the existing ship ballast water management system such that no materials that cause marine ecosystem disturbances are discharged.

The best solution and the same proposition are summarized below.

Minimal modifications are made to the existing ballast water management system such as to discharge seawater with equal conditions to those of the ballast water discharged area.

In order to solve the problem, we have to redefine the solution of the problem as follows.

Regardless of the ballast water discharged area, seawater should always be discharged in the same condition as those of the discharged area. In order to achieve this, a plan is to be implemented in which the ballast water of the ship is continuously discharged and inflowed.

Technical Solution of the Invention

In order to accomplish the above object, the present invention includes a plurality of ballast tanks having a multilayered watertight bulkhead structure by modifying the existing integrated ballast tanks. In the present invention, each of the ballast tanks is provided with a water level sensor and a water level control open-closed device (valve). The present invention has piping and connectors for connecting to pumps for supplying and discharging ballast water. The present invention includes bypass valves for connecting adjacent ballast tanks to each other in order to rapidly transmit ballast water to the ballast tank located at the bottom of the tank. The present invention includes an electronic control unit ECU that smoothly controls inflow and discharge of ballast water. The present invention has a seawater regulating device for regulating the water level while discharging or inflowing water such as ballast water and cooling water in accordance with the sailing conditions of the ship.

Also, the volume of the existing ballast tanks should be increased. That is, when setting Tbal-n (m) (normal ballast water load line) after setting Tbal (m) (minimum planned ballast water line), a part of the tanks that is not used as ballast tank is set as to be used as a ballast tank. Thus, even if the ballast water is discharged, space and devices are provided to maintain Tbal-n (m) (normal ballast water load line). According to the present invention, since the total volume of the ballast water tanks is increased, the ship is more deeply submerged under water than the conventional Tbal-n (m) (normal ballast water load line).

Effects of the Invention

As described above, the present invention relates to a ballast water management apparatus for a ship of double hull structure, and more particularly, to a ballast water management apparatus when a cargo ship of double hull structure is sailed with an empty storage state without loading cargo. The present invention manages and controls an automatic regulating device so that the ballast water is continuously and sequentially exchanged by using seawater stored in a plurality of multi-layered ballast tanks as cooling water and man-made water. In this way, it is possible to integrate the dualized method for using seawater within the ship, and to electronically and automatically manage and control the ballast water.

In addition, all of the seawater, that is inflowed waters at first, is discharged during ship sailing. Accordingly, seawater having the same conditions as those of the sea in the port of entry shall be discharged to the port of entry. As a result, there is an effect of preventing the ecosystem disturbance caused by the transport-prohibited life species in the ballast water.

Also, compared with that the conventional method in which the energy used for storing and discharging the ballast water corresponds to the net profit of the ship that is 3 to 5% of the fuel used by the ship, the present invention can replace a part of the energy for ballast water inflow and discharge with the energy for cooling water and other water, which has the effect of increasing the profit of the ship through energy saving.

Also, the ballast water is constantly exchanged during ship's sailing. It therefore provides the effect of satisfying the requirement that ballast water should be exchanged at a point 200 meters or more from the coast and at a depth of 500 meters or more. As a result, the ship can enter the port without being anchored in the outer port, thus increasing the number of ship sailings.

Further, since the present invention has ballast tanks having a multi-layered watertight bulkhead structure, the stability of the ship is improved, and as a result, the possibility of sinking due to damage to the ship can be minimized and the ship insurance cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating an operation process of a ballast water management method using an integrated seawater management feature according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a conventional management method of ballast water treatment.

FIG. 3 is a piping view showing seawater and fresh water pipes conventionally used for various purposes.

FIG. 4 is a sectional view showing structure of a conventional integrated type ballast water tank.

FIG. 5 is a cross-sectional view showing a multilayered ballast tank according to an embodiment of the present invention.

FIG. 6 is a block diagram showing a control element of an electronic control unit ECU according to an embodiment of the present invention.

FIG. 7 is a flowchart showing a method of managing and integrating seawater of a ship.

FIG. 8 is an extract from the Korea Register of Shipping Rules for the ballast water line and the load line in Korean ships.

FIG. 9 is a correlation table of Dwt and ballast water amount of a ship in general.

FIG. 10 is a sectional view of a general ballast water tank structure.

FIG. 11 is a classification rule for general ballast water load equipment.

FIG. 12 is a schematic diagram of a typical ballast water tank arrangement.

FIG. 13 is a schematic diagram showing the method of ship ballast water management recommended by MEPC (Marine Environment Protection Committee) under IMO (International Maritime Organization) of the United Nations.

FIG. 14 is a schematic view showing the transport-prohibited life species.

FIG. 15 is a schematic view showing the pollutant discharge regulations on the open sea.

FIG. 16 is an association chart analyzing the cause of the ecosystem disturbance problem caused by the ballast water.

FIG. 17 is the best solution for problem solving.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be described below with reference to the accompanying drawings.

First, the structure of the automatic ballast water regulating apparatus will be described below with reference to FIGS. 1, 5, and 6.

The present invention comprises a plurality of ballast water tanks having a multi-layered watertight bulkhead structure, provided by modification of a conventional integral ballast tank structurally modified,

additional ballast water tanks having watertight bulkhead structure,

water level sensors for sensing water level of each of the ballast water tanks,

open-close units (valves) for water level control,

piping and connectors for connecting to pumps,

bypass valves for transporting ballast water in a ballast water tank to an adjacent ballast water tank,

piping and connectors for connection to cooling water and water for other uses, and

an electronic control unit ECU that smoothly controls the above elements, etc.

It is advantageous that the volume of the additional ballast water tanks having the watertight bulkhead structure is the same as that of the tanks for storing the seawater used as the cooling water and the water for miscellaneous use.

The technique of the present invention has the effect of automatically controlling the seawater according to various uses, such as ballast water, cooling water, and miscellaneous use water depending on the application.

Further, through the above-described technique, there is an effect of fundamentally preventing the ecosystem disturbance problem caused by the transport-prohibited life species, which is not available in the conventional ship ballast water management apparatus. The details will be described with reference to the drawings.

When the cargo is not loaded, the inlet and outlet valves 11, 12, 13, and 14 of FIGS. 5 and 6 are opened and the pumps 22 and 24 are operated to save the ballast water up to the top tank of the side tanks 102, and then the ship starts sailing. The level detector 500 of FIG. 6 senses the water level and the controller 600 electronically controls various elements or devices.

Upon beginning of the sailing, a large amount of technical water is required to operate the engine and various machinery. In addition, and seawater for residential water and miscellaneous use water will be continuously inflowed. The inflowed seawater is either stored or used continuously by operations of pumps. The seawater of the bottom ballast water tank 121 of FIG. 1 is used as technical water such as cooling water and miscellaneous use water, and then is discharged out of the ship by a drainage unit 400's operation. When the seawater is discharged out of ship, the bottom ballast water tank 121 is emptied. The water level at which the ship is submerged under water reaches the original designed normal ballast water loading line. At this time, the control unit 600 controls the bypass valve 62 of the un-emptied bottom ballast water tank 121 to open, and the emptied ballast water tank is filled with the seawater of adjacent ballast tank through the bypass valve. In this way, the emptied tank is refilled by the seawater of the adjacent side tank 123. When the top tanks of the side tanks are sequentially emptied, the water level sensor 61 sends a signal to the control unit so as to open the seawater inlet valves 11, 12, 13, 14, to activate the pumps, and to fill the top tanks, and then to stop the pumps 22, 24, which are repeatedly performed. The time taken for the seawater of each of the ballast water tanks to be exchanged is designed to be from 30 minutes to about 90 minutes. Through such continuous and sequential use of seawater, all of the seawater is exchanged during ship's sailing.

In the method of using the ballast water treatment device in some cases to processing active substances in seawater before discharging, the discharged seawater is in a completely different state from that of the seawater of the discharge sea area, regardless of the method. Therefore, these method causes additional problems.

In addition, the present invention technology is designed to continuously and sequentially exchange the ballast water during the ship's sailing. In the case of cargo ships sailing the ocean, the ballast water is exchanged at open sea area of more than 20 miles from the coast and the water depth exceeds 500 meters, so that not only does it meet IMO regulations, but it also has the effect of satisfying all USCG US Coast Guard regulations.

Further, according to the present invention, it is not necessary to separately store seawater for various uses such as ballast water, cooling water, and miscellaneous use water, since the seawater stored in the ballast water tanks is used. As a result, there is no need to use energy for storing or discharging the ballast water, so there is fuel saving effect equivalent to 3˜5% of ship fuel. This is the amount corresponding to the net profit of ship sailing.

A ship equipped with a ballast water tank with multi-layered watertight bulkhead structure will inflow seawater only into the broken ballast tank even if the ship's shell is damaged by impact. Therefore, there is an effect that the ship restoration is remarkably superior to the restoring force at the time of breakage occurring in a ship having the conventional integral type ballast water tank.

In addition, those skilled in the art can understand that various changes and modifications can be made therein without departing from the subject matters of the disclosure. Thus, such changes and modifications fall within the spirit and scope of the disclosure.

REFERENCE NUMERALS

10: fresh water storage tank, 11,12,13,14,15,16: open-close unit (valve), 20: desalination device, 22,24: ballast water pump, 30: seawater treatment device, 50: integral type ballast water tank, 52: supply pipe for mechanical devices water, 54: supply pipe for residential water, 61: water level sensor of ballast water tank, 62: bypass valve, 100: Sectional side view of a double hull structural ship, 101: bottom, 102: hull outer wall, 104: sea surface, 120: integral ballast water tank group, 121: bottom ballast water tank, 122: integral side ballast water tank, 150: discharge pipe, 400: drainage unit, 500: water line sensor, 600: electronic control device.

APPARATUS FOR AUTOMATICALLY MANAGING BALLAST WATER OF SHIP, AND OPERATION METHOD THEREOF

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