WO2008013505A1

WO2008013505A1 - A bulk cargo transportation system

Info

Publication number: WO2008013505A1
Application number: PCT/SG2006/000215
Authority: WO
Inventors: Chee Kit Chung
Original assignee: Imc Solution Shipping Management Pte Ltd
Priority date: 2006-07-28
Filing date: 2006-07-28
Publication date: 2008-01-31

Abstract

The present invention relates to a transportation system for transporting bulk cargo from a very large bulk carrier (VLBC) (10) to an onshore bulk terminal and stockyard. The transportation system includes an offshore receiving hopper (14), an offshore conveyor (16), piles (18) and a positioning sensor system (20) for VLBC loader and offshore receiving hopper.

Description

A BULK CARGO TRANSPORTATION SYSTEM

FIELD OF INVENTION

The present invention relates to a transportation system for transporting bulk cargo from a very large bulk carrier (VLBC) to an onshore bulk terminal and stockyard.

BACKGROUND OF INVENTION

The rapid growth of developing countries such as China and India has created a surge in the demand for industrial bulk cargoes. The industrial bulk cargoes include commodities such as coal, iron ore, minerals, building material and grains. The demand for ocean transportation for these cargoes has resulted in an unprecedented rise in freight rates. The inability of discharge ports to catch up with the rapidly rising throughput has resulted in severe port congestion at many ports.

The conventional solution to the problem of high freight rates has always been the use of larger vessels. The current level of demand for industrial bulk cargoes, particularly in China and India fully justifies the employment of VLBCs. These are vessels are commonly known as Capesize vessels and they are above the 150,000 dwt range. Currently, smaller vessels which are commonly known as Panamax vessels are used where the current upper limit is around the 65,000 dwt range. The Panamax vessels are usually not fitted with cranes for unloading, and therefore needs to be unloaded by shore facilities at the discharge ports. The employment of VLBCs to solve the rising bulk cargo demand is hampered by a number of technical issues. For example, VLBCs require ports and terminals with deeper drafts and require approach channels with the corresponding depths. VLBCs also require investment in very large shore discharging facilities such as unloaders and shore cranes. With the increase in size and weight, such equipment is reaching the limit of their capacity, and rates of discharge using such equipment are approaching the point of diminishing returns.

Furthermore, large cargo volume requires larger stockyard. It is difficult to find inexpensive land with large area and the right soil condition next to deep water channel.

Offshore loading operation using floating cranes or ship's gears, with lighters and barges, are not an option because of the huge beam and freeboard of VLBCs. Also, the dynamic motion of the VLBCs in wind and wave condition creates difficulties in the accurate discharge of cargo into hoppers or other receptacle.

Developing countries such as India and China are rather poor in terms of availability of deep water coastlines, especially near centres of industry. With competing use of such deep coastlines for other shipping requirements, such as container ports, land costs are high. In many cases, they are simply unavailable.

The costs of dredging to maintain the required channel depth, as well as the alongside terminal depth, are prohibitive. Furthermore, the civil engineering costs for the building of terminals with massive shore crane facilities to take VLBCs are excessive. Currently, port equipment manufacturers do not have sufficient experience to build unloading equipment suited to these larger bulk carriers.

Another important consideration is that for VLBCs, the correct positioning for the unloading is critical as any of the accidental clash between the loader and the receiving hopper will cause substantial damage to the ship discharge boom or VLBC loader and hopper.

SUMMARY OF INVENTION

Accordingly, there is provided a transportation system for transporting bulk cargo from a VLBC with an onboard self unloading system to an onshore bulk terminal and stockyard, the transportation system includes at least one offshore receiving hopper, at least one offshore conveyor, at least one pile and at least one positioning sensor system for VLBC loader and offshore receiving hopper.

The present invention consists of several novel features and a combination of parts hereinafter fully described and illustrated in the accompanying drawing, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantage of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of facilitating and understanding of the present invention, there is illustrated in the accompanying drawings, from an inspection of which, when considered in connection with the following description, the invention, its construction and operation and many of its advantages would be readily understood and appreciated.

FIG. 1 shows the perspective view of the transportation system according to the preferred embodiment of the present invention;

FIG. 2 shows the side view of the transportation system;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a transportation system for transporting bulk cargo from a VLBC to an onshore bulk terminal and stockyard. Hereinafter, this specification will describe the system according to the preferred embodiments of the present invention. However, it is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the scope of the appended claims.

FIGS. 1 and 2 show the system according to the preferred embodiments of the present invention. The VLBC 10, particularly the VLBC 10 in the size range of 150,000 to 300,000 dwt is provided with an onboard self unloading system 12. The VLBC 10 makes the ocean voyage at a substantially lower freight rate than smaller conventional vessels. The VLBC 10 is loaded at the loading port either using conventional shore facilities or using offshore floating equipment.

The key components and features of the system include an offshore receiving hopper 14, an offshore conveyor 16, piles 18 and a positioning sensor system 20 for VLBC loader and offshore receiving hopper.

The description of the operation of the transportation system of the present invention will now be described. As shown in the figures, the onboard self unloading system 12 includes a number of cargo cranes located on one side of the VLBC 10 together with a system of hoppers and conveyors on deck, arranged in such a way that the bulk material can be discharged over the ship side by way of a discharge boom and chute.

These cargo cranes are fitted with large grabs, and can reach all of the cargo holds of the VLBC 10. Next to the cargo cranes are a corresponding number of cargo hoppers. In operation, the cargo from the hold is grabbed and hoisted, and discharged into the deck hoppers. The deck hoppers are connected by means of a system of deck conveyor belts, at the end of which is a discharge boom. This discharge boom consists of a telescopic conveyor belt, supported on a light steel structure that enables it to be hoisted and slewed into position. At the end of the discharge boom is a discharge chute, directing the cargo into the offshore receiving hopper 14. During operation, the cranes work together with the hoppers and belts to give an almost continuous flow of cargo through the discharge boom.

The end of the discharge boom is fitted with an electronic positioning sensor system 20 to monitor the relative position between the end of the discharge chute and the offshore receiving hopper 14. The positioning sensor system 20 provides feedback to a control system by which the slewing and luffing angle of the boom can be continually adjusted.

Instead of a conventional berth, the VLBC 10 docks against a number of piles 18 called dolphins 18 arranged in a straight line in the middle of the sea. Except for a light deck to accommodate the mooring crew, the dolphins 18 are not decked, thus minimizing the structural strength requirements. The dolphins 18 are substantially tendered to take into account the mooring forces. Mooring bollards are fitted to the dolphins 18 to enable the ships' lines to be secured and they are piled structured suitably tendered to allow the VLBC 10 to be tied securely in an offshore location. The dolphins 18 serve the important function of keeping the VLBC 10 in position relative to the offshore receiving hopper 14. Because the location is offshore, it is easy to find sites of sufficient depths as well as other meteorological and hydrographic conditions for safe mooring.

After the VLBC 10 is tied up at the dolphins 18, the cargo onboard is discharged via the discharge boom, onto the offshore receiving hopper 14 mounted on piles located in a suitable position relative to the dolphins and the VLBC 10. The relative position of the boom and the offshore receiving hopper 14 is monitored electronically, as well as by sight, to facilitate adjustment of the boom position to take account of the change caused by wind, current and tide and reducing draft of the VLBC 10 as the cargo is discharged.

The offshore receiving hopper 14 is provided on the shore side direction of the dolphins 18. The offshore receiving hopper 14 can either be fixed, i.e. mounted directly on piles, or mobile, i.e. mounted on rails on top of a line of piles.

The offshore receiving hopper 14 and the shore terminal are connected by means of a very long conveyor 16 over water. The accompany drawings show the offshore conveyor as applied in the present invention. The conveyor 16 is supported by a light framed structure, which besides carrying the conveyor only carries a walkway. The conveyor 16 can, if required, be several kilometres in length. The conveyor 16 is supported by a relatively light steel structure, because only the weight of the conveyor 16 needs to be taken into account. Since it is very light, it can be held up by piled supports between very large spans. As a result a very long conveyor 16 can be constructed relatively inexpensively over the sea.

Upon reaching the end of the conveyor 16 at the onshore bulk terminal and stockyard, the cargo is stacked using conveyor stacking equipment in the stockyard. The onshore bulk terminal and stockyard is a conventional stockyard. However, being located in an area which is otherwise not suited for port construction, the land costs would be very much lower. It can also be located some distance from the shoreline.

The positioning sensor system 20 for VLBC loader and offshore receiving hopper, by connecting to the motors that control the VLBC loading boom, will help the accurate positioning of the bulk loading process, i.e., to ensure that the loading process is targeted to the centre point of offshore receiving hopper 14, and avoid the possible severe clash of the loader and the offshore receiving hopper 14 during bad weather condition due to ship motion.

The positioning sensor system 20 can consist of any number of sensors and is utilised for the calibration of three dimension position, i.e. the vertical position sensing, the horizontal position sensing and height sensing.

In the vertical position sensing, the sensor attached to the VLBC loader calibrates the vertical space position of loader mouth is referred as X_b and the sensor attached to the offshore receiving hopper 14 calibrates the vertical space position of the Optimal Loading Point (OLP) for hopper is referred as X₀.

In the horizontal position sensing the sensor attached to the VLBC loader calibrates the horizontal space position of loader mouth is referred as Y_b and the sensor attached to the offshore receiving hopper 14 calibrates the horizontal space position of the OLP for the offshore receiving hopper is referred as Y₀.

In the height sensing, the sensor attached to the VLBC loader calibrates the horizontal space position of loader mouth is referred as Z_b and the sensor attached to the offshore receiving hopper 14 calibrates the horizontal space position of the OLP for the offshore receiving hopper 14 is referred as Z₀.

In such measurement, the OLP space position would be: (X₀, Y₀, Z₀), and the space position for VLBC loader mouth would be (X_b, Y_b, Z_b) whereas the off-position calibration between the VLBC loader mouth and OLP for receiving hopper is then: (X_b - X₀, Yo - Y_b>

This off-position calibration signal will be transmitted to the Central Motor Control Room of the VLBC 10 and the motor will adjust the loader mouth to the OLP for balanced and smooth bulk loading into the offshore receiving hopper 14.

The principle of sensing and positioning is to move the VLBC loader mouth across the relative space distance (X_b - X₀, Yo - Yb_> Z_b - Z₀) to OLP for the offshore receiving hopper 14. Thus the sensing feature is not confined to the measurement of (X₀, Y₀, Z₀) and (X_b1Y_b1Z_b), but also could be the measurement of the relative space distance.

The distance sensors could be installed at any points around the offshore receiving hopper 14 or on the rack around the VLBC loader mouth. There are many alternates on the number of sensors that are to be installed or the installation points of sensors.

The transportation system of the present invention does not require massive discharge port equipment and it is suited for a large range of bulk cargoes, including coal, iron ore, bauxite, fertilizers, mineral sands etc. Further, it provides a very important need of optimising the total supply chain costs of transportation of industrial bulk material, enabling cargoes to be transported in greater amounts over larger distances, in a more efficient and effective manner. It also provides the reduction of freight rate due to the use of VLBCs, the reduction of terminal handling costs because of the reduced capital requirement resulting from lower land costs as well as civil engineering costs for an alternative land based facility of similar throughput capacity, the increase in option for site selection in countries where suitable port locations are difficult to find and the reduced operating costs due to the removal of need for the dredging of channels and port basin. The stable and safe unloading process through the positioning sensor system 20 avoids any severe clash of loader and receiving hopper during bad weather condition with high tide waves. Furthermore, the short development and construction period enabling large unloading facilities to be constructed within a very short period of time.

Claims

1. A transportation system for transporting bulk cargo from a very large bulk carrier (VLBC) (10) with an onboard self unloading system (12) to an onshore bulk terminal and stockyard, the transportation system includes at least one offshore receiving hopper (14), at least one offshore conveyor (16), at least one pile (18) and at least one positioning sensor system 20 for VLBC loader and offshore receiving hopper.

2. The transportation system as claimed in claim 1, wherein the onboard self unloading system (12) includes a number of cargo cranes located on one side of the VLBC (10) together with a system of hoppers and conveyors on deck, arranged in such a way that the bulk cargo can be discharged over the ship side by way of a discharge boom and chute.

3. The transportation system as claimed in claim 2, wherein the cargo cranes are fitted with large grabs.

4. The transportation system as claimed in claim 1 , wherein the discharge boom is fitted with an electronic positioning sensor system (20) to monitor the relative position between the end of the discharge chute and the offshore receiving hopper (14).

5. The transportation system as claimed in claim 1, wherein the offshore conveyor (16) is mounted directly on piles (18) or mounted on rails on top of a line of piles (18).