AU604228B2

AU604228B2 - Improved method of disposal and recycling of scrap metal from sea and other vessels

Info

Publication number: AU604228B2
Application number: AU69211/87A
Authority: AU
Inventors: John Didea
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-02-24
Filing date: 1987-02-24
Publication date: 1990-12-13
Anticipated expiration: 2007-02-24
Also published as: WO1988007896A1; AU6921187A

Description

3929-PI JRW:JM AUSTRALIA ,60 2 PATENTS ACT 1952 CCMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Application Number: Lodged: 6Z11/ 87 Complete Specification Lodged: Accepted: Published: Priority: Related Art: This document cunt,1aiv. tile aRm:Umle:tsS

C,"

TO BE CCMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: JOHN DIDEA 23 Irrigation Road, Merrylands, New South Wales, 2160 AUSTRALIA JOHN DIDEA ARTHUR S. CAVE CO.

Patent Trade Mark Attorneys Goldfields House 1 Alfred Street SYDNEY N.S.W. 2000

AUSTRALIA

Complete Specification for the invention entitled "IMPROVED METHOD OF DISPOSAL AND RECYCLIN OF SCRAP METAL FRCM SEA AND OTHER VESSELS".

The following statement is a full description of this invention including the best method of performing it known to me:- 1 ASC 49 i

A

0- IMPROVED METHOD OF DISPOSAL AND RECYCLING OF SCRAP METAL FROM SEA AND OTHER VESSELS The present invention relates to an improved method for the recovery of scrap iron from disused vessels such as but not limited to ships which have been removed from service and discarded.

In the past a number of methods for disposal of ships have been employed most of which are time consuming and labour intensive. The principle method of dealing with disused ships has been to dry dock the ship and then to systematically 00 000 o 0 dismantle the superstructure using heat cutting equipment.

ooooo a 000 0 0 Due to the massive size of ships and the amount of scrap 00 metal from which they are fabricated it has been established oOO0 that it is well worthwhile attempting to recover usable aoo materials from condemned ships.

0O Owners of condemned ships have a number of courses of S 0 o action which they can adopt to dispose of their ships. The S condemned ship can be towed out to sea and sunk to create artificial reefs to attract fish. This is the least attractive method financially but more attractive environmentally.

Despite the latter, a further disadvantage is that the sea becomes a dumping ground.

Despite the disadvantages of this course of action it overcomes the problem of anchoring of condemned ships in harbours throughout the world while they await an ultimate fate.

Alternatively, an owner can sell a ship at the end of its life to a country which has the facility for dismantling the ship and also the need for the scrap material which can be 2 0193B

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salvaged from it. The disadvantage of this course of action is that the ship must be sailed to an often distant destination the cost of which must be borne by the vendor. Furthermore, the resale value of condemned ships is poor and much of the financial gain from a sale is offset by the costs of transportation of the ship to the scrap yard.

This problem is exacerbated by the fact that not all countries have facilities for the handling of condemned ships and those that have are generally in the northern hemisphere thus disadvantaging ship owners in the southern hemisphere.

00 0 oo Once the ships reach the scrapyards the ship is generally 0o 0000 0 0 cut systematically into pieces of a size which can be handled 00 0 o 00 0 00 0 0 by a crane. The work is highly labour intensive. The cranes oo load the cut pieces of the ship onto trucks or bogies for 9000 transportation to steel works where the pieces are melted down in blast furnaces.

The principle enemy of this process is cost and time taken. The wrecking of the ship could take anything up to twelve months depending upon the size of the ship and other considerations.

The contributing factors to the high costs being the cost of cutting due to the high consumption of either gas or electricity and the high cost of labour. Furthermore, the dry docks are occupied by uneconomical and unproductive ships for lengthy periods during dismantling.

An alternative to the outright sale of a condemned ship has been for owners to negotiate an agreement with a local steel industry whereby the steel plant contracts to dismantle 3 0193B _1_ the ship and recover the iron.

The returns from disposing of ships in these ways are generally low for the ship owners unless the ship is based in a country with local facility for optimising economic returns S 5 from scrap metal.

In many countries there is a clear need for utilisation of scrap metals for recycling purposes thus increasing the necessity in these countries to economically capitalise on the resource provided by disused vessels instead of importing iron from other countries.

0 for obtaining the optimum economic benefit from the metal 0 o 0-.0 resources in old ships and other vessels and at the same time 0 0 0 00 0 So°°o utilising the void spaces in the hulls of ships for filling 00oooo with additional scrap metals for melting.

fo In some countries previously, there have been profits made 0" 0 from contractural relationships which have been instituted between shipping companies and steel industry companies for 0' importation of minerals, however, the present systems and methodology utilised in the capitalisation of these agreements do not optimise the economic benefits which are necessary for It i these countries.

It is therefore desirable in many countries whose mineral wealth is poor to obtain an improved source of iron thereby reducing the dependancy on imported iron and associated minerals and to improve the local steel industry in these countries.

MIany countries such as but not limited to Japan, America, 4 0193B t

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Germany, Holland, Greece and Norway have many ships which are now out of service but which possess large amounts of useable steel in their superstructures. These ships lay idol and useless in their present state. Many ships having tens of thousands of tons of scrap steel could be recycled by utilisation of the proposed method of the present invention.

New ships could conceivably be built from the reprocessed scrap metal thus creating a new industry in these countries.

The present invention seeks to overcome the problems previously experienced in the disposal of condemned maritime 0 000 00a and smaller maritime and/or land vessels by providing an Sefficient method for melting down these vessels without the o, disadvantages which have hitherto previously been referred to 0 oo in relation to the prior art methods.

In its broadest form the present invention comprises a system for the disposal of vessels and the recovery of the 0 0 0C scrap materials obtained therefrom, said system comprising: a furnace adjacent to or near a sea-land interphase; 0 0t an access from the sea to said furnace via a means comprising a dry or wet dock having guide means for vessel 4 support wherein the central longitudinal axis of the said dry S or wet dock approximately aligns with the centre of an opening, to said furnace; a means for transferring a vessel from the said dry or wet dock to said furnace via said opening; whereby, when scrap materials are to be recovered from a vessel, said vessel is transferred from the sea onto the said dry or wet dock, urged into said furnace by said transferring 5 0193B means via said opening and acted on by a heating means to thereby convert the vessel into molten metal for subsequent recovery.

In the preferred embodiment the said furnace has, a central heating chamber means and an air supply and air exit means; a sealable exit for allowing the passage of molten metal produced in the said furnace to be transferred to a transportation means whereby when a vessel is to be melted down, the vessel is moved from the ocean onto the said dry or 0o wet dock, urged into the said blast furnace, acted upon by the oooo Sheating means in the blast furnace, and thereby converted into o molten metal; wherein the said molten meta. is transferred to a *0 transportation means via the said exit in the said furnace.

000oooo Also, in the preferred embodiment the system's blast Po furnace is constructed in a coastal location utilising the geographic conditions most suitable for the construction of the furnace such as a rocky cliff. Preferably, the furnace chamber Swould be constructed by hollowing out the cliff face to the desired depth of penetration and diametrical size such that the S natural rock material would form the walls of the furnace. The o; walls would preferably be sealed and insulated to ameliorate the problems manifested by porosity of the rock material and also to minimise heat dissipation.

Ideally the dock structure abuts the entry to the furrnace such that its guide rails align with and adjoin guide rails within the furnace chamber.

The dock can be arranged in various attitudes according to 6 0193B kL the manner in which the ship is to be introduced into the furnace. To this end the dock is either sloped downwardly or upwardly towards the opening of the furnace.

The optimum positioning for the dock would be in a geographical location which is an optimum compromise between water depth and sea bed slope such that the dock can be built at a suitably shallow angle either upwardly or downwardly and also such that a vessel can be easily aligned with the dock.

The constructed attitude of the dock also dictates by particular tides at the geographic locality of the furnace.

Where tides are too small to enable gravitational access to the o bottom of the furnace opening the dock can be extended until it o o 0 0 0 00o0 reaches beneath the sea so the vessel can be floated onto the 0 00 dock at high tide. In addition a series of winches drag the 0 15% vessel along the dock via rails provided thereon and into the 0000 furnace chamber.

0°0 Preferably, the adjustable doors to the furnace chamber q* are either slideably or pivotally mounted such that the cross sectional area of the entrance to the furnace can be varied 0 4! according to need.

The invention will now be described in detail according to a preferred but non-limiting embodiment wherein: 0 00 Fig. 1 shows a longitudinal elevation layout of the system according to one embodiment of the present invention; Fig. 2 shows a front elevational view of the opening to the furnace chamber; and Fig. 3 shows a closer longitudinal view of the interelationship between the furnace and the transportation 7 0193B means.

Fig. 4 shows a longitudinal elevational view of the system whereby the vessel is gravity fed into the furnace chamber.

Referring to Fig. 1 there is shown a cross sectional view of the essential features of the vessel disposal and material recovery system accoraing to the preferred embodiment of the present invention. A vessel 1 is shown in a first position anchored at sea in close proximity to a blast furnace 2 preferably formed in a rock headland in readiness for furnace treatment. The system will he described with reference to a ship, however, the system can be used for non-maritime vessels 0o 0 0 as well.

0 0 0 oThe furnace 2 comprises a large chamber 3 which is hewn o o 0.o from natural coastal rock formation 4 or constructed 0 oo ol °o artificially (not shown) when geographic conditions are not suitable. It is intended that the chamber 3 be of such a size as to accommodate ships of large proportions. The walls of the furnace chamber 2 are insulated by known methods such as with bricks or silica blocks which provide a continuous lining to minimise heat loss through the rock or existing geological structure. Porosity must also be eliminated and this can be achieved by sealing the surface material prior to insulating the surface. It is envisaged that the furnace is designed according to known furnace technology and comprises at least five air/oxygen feed systems 5 to fire the furnace. Each of the air feed systems 5 comprises a suction/delivery fan being supplied with air from an air intake shaft 6. Each of the air feed systems is adjoined to the furnace chamber by means of a 8 0193B typical air supply line 7. The furnace also has an exhaust means 8 which can be adjusted according to exhaust requirements.

The number of exhaust ports vary according to the expected gas volume to be evacuated from the furnace chamber. Each exhaust port is sealable and has a draft creating means such as an axial flow fan.

It is envisaged that preheating of the vessel will take place in the divided smaller chambers of the furnace utilising the heated gases generated by the heat source in the core of the furnace. Each of the divided chambers are provided with adjustable exhaust systems to control heat build up. The heat 0o 0 S in the divided chambers is transferred from the main fire 0 0 source by conduction or convection. Each divided chamber can 0 00 be individually sealed to retain and control the heat in that o00 o 130 particular chamber.

000o To minimise heat loss, the furnace chamber must be of a 0 size which allows the full size of the vessel to be enclosed without unoccupied space being left. Where a furnace is constructed to large specifications and a smaller ship is to be melted, it is proposed that closures such as gates or doors be constructed within the chamber 2 such that unfilled sections of 00. the chamber can be isolated from the section containing the ship so the heat losses and heat required to carry out the melting operation is minimised.

Where a vessel is of excessive size such that it cannot fit wholly within the chamber the vessel is melted in segments with heat being retained in the furnace by the closure of the doors to the divided smaller chambers over the vessel. This 0193B L IP-- illlli- IC -i~iil~minimises heat loss. The doors to the smaller chambers must be adjusted according to the particular profile of the vessel. In order to minimise heat loss it is essential that any void spaces in the chambers be filled with material to be melted.

The furnace is equipped with a heat source 9. The heat required can be provided by a coal fired oven or an electric or gas fired oven according to conventional means; where coal is used the quantity required is calculated according to the amount of heat required in line with conventional methods.

When the furnace is ready for reception of the vessel to be melted and the tidal conditions are favourable, the ship can 0 be guided or towed onto the dock 0 0 0 00 Preferably, the ship can be floated into position at high 0 0 0 .i tide and then secured in position, with the following ebb tide 0 0 4 allowing gentle seating of the ship onto the dock.

0000oooo Alternatively, the ship can be winched into position by 0j winches positioned abreast of the dock on either side (see Fig.

.0"0 Despite the size of the ship, it is anticipated that the load on the winches will be relLtively small in comparison to the overall weight of the ship as the dock will have rollers and the winch will only be pulling the horizontal component of I the resultant weight of the ship.

Fig. 4 shows an alternative embodiment of the dock whereby Ij its attitude is such that the ship is gravitationally fed into the furnace. To facilitate this, the seaward end of the dock must be above the bottom of the furnace opening. The vessel is floated over the dock at high tide. As the tide drops the vessel seats on the dock and is temporarily restrained from 10 0193B

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-1 gravitational movement by a biasing means (not shown) which prevents it moving on the guide rails. When the bias is released the vessel is free to gravitate into the furnace chamber.

Once the ship is placed on the dock it is then transferred into position inside the furnace chamber 3. The entry to the furnace is adapted with adjustable external doors as shown in Fig. 2. The external doors are constructed in such a manner as to enable sealable retention of heat within the furnace when closed.

To this end it is important that the whole ship be within 0 Sthe chamber before the furnace is fired and the melting process S oo begins.

o o oOOO Alternatively, the ship can be partially within the 0 1 o. chamber so that the doors are adapted to close onto the ship superstructure. The latter alternative is considered to be the least desirable due to the potential for excessive heat loss, however, it can be utilised when a vessel is to be melted in S00 S sections.

In operation, due to the downward slope of the floor within the furnace chamber the ship can be fed by gravity into 0 il the central furnace area. The ship is melted down either in or 1 00 0 as a whole. As the ship melts, which normally will be bow j first, the molten metal 11 gravitates into a hopper 12 thence into a bogie 13 which has moulds within it (not shown) so that the molten metal sets as ingots which can be readily transported.

Ideally, when the bow of the ship is presented to the 11 0193B furnaces central heat core it is envisaged that a series of doors within chamber 3 designated as 14, 15, 16 and 17 can be closed over the ship superstructure thus compartmentalising the bow portion of the ship and also the heat. In an alternative embodiment, the chambers defined by doors 14, 15 and 16 are adapted with auxiliary exhaust means to share the load of hexhaust means 5. The aforesaid doors can be slideably and/or pivotally fixed and their surface areas adjustable to accommodate the expected variety of ship profiles. As the bow portion is melted the remainder of the ship can then be gravitationally control fed into the furnace.

C The hoppers 13 once filled then transport the ingots to their designated destination for later use in manufacture of steel goods.

In countries where a dock would not be feasible due to inhospitable coastal geography, it is envisaged that a floating dock be available such that it could be brought into horizontal and axial alignment with the face of the blast furnace opening 44tfor ease of entry therein. This would be suitable in regions there are shear cliffs at the coast vertically penetrating into deep water. The floating dock would be 0* 0 S00 be melted can be properly and accurately aligned with the dock and entry to the furnace.

in the alternative a lock can be constructed 'at the mo..uth of the furnace. A vessel can be floated or urged Into the lock. The look is then pumped out resulting in tt being seated on the dock in the look at the oir 0193al-2 furnace.

Ships by their very nature carry valuable steel in a very diffuse state such that the void spaces within the ship clearly constitute a waste of space. These voids must be heated before the melt down takes place at considerable expenditure of heat energy.

In order to solve this problem it is envisaged that the Si void spaces of condemned and discussed ships be loaded with other metal articles to be melted down so that the heat losses in the void spaces be minimised.

Fig. 3 shows a closer view of the furnace heart. Once inside the furnace chamber ship 1 penetrates into the furnace heart under gravity. Gate 17 can be closed onto the superstructure of the ship to minimise the size of the compartment which is to be heated.

Ideally the inner compartment 18 has its walls lined with bricks to help insulate the furnace.

It is intended that the heat energy generated by the blast furnace from the melting down process be used for operation of alternative sources of energy such as power generation.

Alternatively the energy can be utilised in the heating of water.

The orientation of the tunnel or chamber previously described is by no means the only possible workable orientation. For instance the opening to the furnace may not be able to be placed close to the shore line. Geographic conditions may require that the chamber be disposed metres or kms further inland so that a vessel to be melted would have to 13 0193B i. r L i i be railed from the dry dock overland to the furnace chamber.

The furnace chamber can initially be graded upwards then sharply downwards so that when a vessel is winched up the grade it has more energy to assist its gravitational fall down the incline and into the furnace chamber. The technology exists to drag a laden vessel up such an incline. A series of winches can be disposed either side of .he guide tracks.

Due to the size of this pro)ect and the consequent size of the blast furnace needed the system is intended to be in use 24 hours a day every day for economic efficiently and due to the dificulties in producing the requisite heat levels.

000o0 S° High energy consumption with consequent inefficiency in 0 o oo, production would result from using this system on a part time basis as it would be inefficient to allow the furnace to cool.

i Ships, car bodies, and all manner of waste metals could be I melted down utilising this new system. Due to high energy consumption, it is envisaged that a recycling of excess heat 0 energy be used to assist in heat generation within furnace.

It will be recognised by persons skilled in the at that t numerous variations and modifications can be made to the present invention as broadly described herein without departing from the overall spirit and scope of the invention.

14 0193B

Claims

1. A system for the disposal of vessels and the recovery of the scrap materials obtained therefrom, said system comprising: a furnace adjacent to or near a sea-land interphase; an access from the seF to said furnace via a means comprising a dry or wet dock having guide means for vessel support wherein the central longitudinal axis of the said dry or wet dock approximately aligns with the centre of an opening, to said furnace; a means for transferring a vessel from the said dry or wet dock to said furnace via said opening; whereby, when scrap materials are to be recovered from a vessel, said vessel is transferred from the sea onto the said dry or wet dock, urged into said furnace by said transferring means via said opening and acted on by a heating means to thereby convert the vessel into molten metal for subsequent recovery.

2. A system according to claim 1 wherein the said furnace also comprises: a central heating chamber; a means of supplying heat to said chamber; an air supply entry and exit means to and from said chamber respectively, sealable entry and exit means; said exit means allowing the passage of molten metal produced in said furnace to be transferred to a transportation means adjacent said exit means.

3. A system according to claim 2 wherein the chamber of the 15 00 t 8 t 4 I e i 0193B Ssaid furnace comprises a cavity formed within a geological stratum of the land forming said sea-land interphase according to the geophysical dictates of said geological stratum. 4, A system according to claim 3 wherein the walls, roof and floor of the said furnace chamber are formed by the material of Ssaid geological stratum. A system according to claim 3, wherein the walls and roof i of said furnace chamber are formed by a shoring structure located within said cavity.

6. A system according to any one of the foregoing claims wherein the elevation of the bottom of said furnace opening Sapproximate the sea level at either high or low tide.

7. A system according to any one of claims 1 to 5 wherein the elevation of the bottom of said furnace opening approximates the sea level at any position between high tide level and low tide level.

8. A system according to claim 7 wherein the said dry or wet dock comprises an elongated platform having one of its ends disposed seawardly and the other end terminating at the opening to said furnace chamber.

9. A system according to claim 8 wherein the said platform has guide rails which are adapted to receive and support the vessel. A system according to claim 9 wherein the said seaward end of said platform is disposed at a higher elevation than the end adjacent said furnace opening. 11ii. A system according to claim 10 wherein the means of transfer of said vessel from said dock to said furnace is by 0 02J 16 7K gravity feed.

12. A system according to claim 11 wherein the gravity feed is controlled against a means biased against the direction of said gravity feed.

13. A system according to claim 9 wherein the said seaward end of said platform is disposed at a lower elevation than the end i t i adjacent said furnace opening.

14. A system according to claim 13 wherein the means for i transfer of said vessel from said dock to said furnace comprises a motorised winch or winches and pulley arrangement. I 15. A system according to claim 14 wherein the floor of the furnace chamber has guide~ rails which align with the guide rails on said dock.

16. A system according to claim 15 wherein the guide rails within said chamber are sloped downwardly away from said furnace opening to facilitate passage of said vessel into said furnace. S17. A system according to claim 15 wherein the slope of the Sfurnace chamber guide rails is between 00 and 250.

18. A system according to claim 17 wherein the said furnace chamber is up to 200 metres long. til 4 S 19. A system according to claim 18 wherein the said sealable entry comprises a set of adjustable doors which, when closed, hermetically seal said furnace chamber against gas or liquid ingress or egress. A system according to claim 19 wherein said adjustable doors are adapted for pivotal or slidable motion such that the area of the opening to said furnace can be varied. 17 0193B dry or wet dock, urged into said furnace by said transferring 0193B Ld r7 33 S21. A system according to claim 20 wherein the furnace chamber is divided into a series of smaller chambers.

22. A system according to claim 21 wherein the source of heat to said heating means is provided by either gas, electricity or i solid fuel.

23. A system according to claim 22 wherein the furnace chamber has at least one exhaust means adapted for clearing the chamber of gases during and after heating.

24. A system according to claim 23 wherein the said exhaust means are each connected to a vent pipe to facilitate the escape of exhaust gases from said chamber. A system according to claim 24 wherein each of said smaller chambers are also adapted with exhaust means to evacuate gases from said smaller chambers.

26. A system according to claim 25 wherein the furnace chamber has a chute for external egress and recovery of molten material into or onto a transportation bogie.

27. A system according to claim 26 wherein the said vessel is preheated by gases in said smaller chambers prior to entry into that part of the furnace chamber closest to the heat source.

28. A system as hereinbefore described and with reference to the accompanying illustrations. DATED this 3rd day of September, 1990. JOHN DIDEA By His Patent Attorneys e ~ARTHUR S. CAVE CO. 0202j 18