AU2007231797A1

AU2007231797A1 - Desalination and power generation plant

Info

Publication number: AU2007231797A1
Application number: AU2007231797A
Authority: AU
Inventors: Jolyon Emmanuel Nove
Original assignee: JOLYON NOVE
Current assignee: JOLYON NOVE
Priority date: 2006-11-08
Filing date: 2007-11-08
Publication date: 2008-05-29

Description

203266199_2 0 0 a p.0

AUSTRALIA

Patents Act 1990 (Cth) Complete Specification Jolyon Emmanuel Nove Invention Title Desalination and Power Generation Plant The invention is described in the following statement: Blake Dawson Patent Attorneys Level 37, Grosvenor Place 225 George Street Sydney NSW 2000 Telephone: 61 2 9258 6000 Fax: +612 9258 6999 Ref: DGC JMOK 02-1425-1144 203266199_2 2 DESALINATION AND POWER GENERATION PLANT O FIELD OF THE INVENTION The present invention relates broadly to a desalination unit and a desalination plant for producing desalinated water. The invention also relates generally to a method of producing desalinated water from seawater.

_BACKGROUND OF THE INVENTION It is recognised that desalination technology at least in part provides a solution to water shortages across the globe. However, the construction and operation of a traditional desalination plant brings with it associated environmental problems. The desalination plant itself should ideally be located close to heavily populated urban areas whilst being near a source of saltwater. This is inherently difficult as land space is scarce close to cities and other densely populated areas. The plant will consume relative large amounts of electricity which in many instances are from thermal power stations which produce excessive greenhouse gas emissions. The infrastructure, such as seawater intake, brine discharge and desalinated water supply lines are destructive to the landscape and generally invasive and unattractive. The desalination plant also requires power transmission lines for connection to the grid or often remotely located thermal power stations. These factors together present serious issues which not only delay and complicate construction approval but also adversely threaten and impact on the environment.

SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a desalination unit being adapted to operatively couple to a wind turbine for driving the desalination unit to produce desalinated seawater.

According to another aspect of the invention there is provided a desalination plant comprising: a floating structure being adapted to be positioned in a body of seawater; a wind turbine mounted to the floating structure; and a desalination unit located at the floating structure and being operatively coupled to the wind turbine for driving the desalination unit which is adapted to produce desalinated water from seawater of the body of seawater.

203266199_2 3 Preferably the floating structure includes a floating vessel or barge which is adapted to be moored offshore in the body of seawater. Generally the desalination plant in its entirety or O in part is arranged to be readily relocated. The vessel or barge may include a rudder Z together with self-steering equipment to promote alignment of the vessel or barge with the wind to increase the efficiency of the wind turbine.

Preferably the desalination plant also comprises one or more floating reservoirs adapted Sto locate alongside the floating structure and being operatively coupled to the desalination unit for the storage of desalinated water produced by said unit. More preferably the (i floating reservoir is of a collapsible construction which is designed to contain desalinated water and be towed in its expanded state whereas in a collapsed state it is designed for compact transportation to the floating structure. The collapsible reservoir is preferably fabricated from a flexible material, such as a polymer or plastics material.

Preferably the wind turbine is one of a plurality of wind turbines mounted to the floating structure. Alternately, the wind turbine may include a pair of contra-rotating turbine blades dedicated to a common mast of the corresponding wind turbine.

Preferably the desalination unit includes primary treatment means in the form of a reverse-osmosis (RO) filter arrangement being operatively coupled to secondary treatment means in the form of an ultraviolet (UV) steriliser. Alternatively the secondary treatment means is in the form of a charcoal filter or equivalent. The desalination unit may also include preconditioning units such as filters and oil/water separators, located upstream of the primary treatment means.

Preferably the desalination plant also comprises a wave power device operatively coupled to the floating structure for additionally driving the desalination unit.

Preferably the desalination plant further comprises one or more seawater pumps operatively coupled to and powered by the wind turbine for pressurisation of the seawater upstream of the desalination unit. The seawater pumps may be: directly driven by the wind turbine and/or the wave power device; (ii) electrically powered by an alternator or equivalent electrical generator which is directly driven by the wind turbine and/or the wave power device; or (iii) of a hybrid design being either mechanically or electrically powered.

Preferably or alternately the electrical generator driven by the wind turbine is adapted to provide power for transmission remotely, for example onshore.

203266199_2 4 According to a further aspect of the invention there is provided a method of producing ri desalinated water from seawater, said method comprising the steps of: O providing a desalination plant including a floating structure at which a desalination Z unit is located, the desalination unit being operatively coupled to a wind turbine; locating the desalination plant in a body of seawater; driving the desalination unit utilising energy generated by the wind turbine and thereby producing desalinated water from seawater of the body of seawater.

Preferably the method also comprises the step of storing the desalinated water produced in one or more floating reservoirs located alongside the floating structure. More preferably the method involves towing the floating reservoirs onshore for discharge of their desalinated water contents. Even more preferably the method subsequently involves collapsing of the floating reservoirs for shipping and/or other compact transportation to the floating structure for redeployment.

For the purpose of this specification, seawater is to be understood as including salt water as well as brackish water or saline water of varied concentrations.

BRIEF DESCRIPTION OF THE DRAWINGS In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a desalination plant together with a method of producing desalinated water from seawater will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic of a desalination plant according to one embodiment of the invention; Figure 2 is a schematic of the desalination plant of figure 1 together with an associated floating reservoir; Figure 3 is a schematic of another desalination plant showing a variant of the wind turbine; and Figure 4 is a schematic of one or more of the reservoirs such as that shown in figure 2 being transported onshore.

203266199_2 0 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in figure 1, there is a desalination plant designated generally as 10 comprising a Z floating structure 12 to which a wind turbine 14 is mounted. The wind turbine 14 is operatively coupled to a desalination unit 16 for the production of desalinated water from sea water of the body of sea water 18. In this embodiment the desalination plant 10 is located offshore in an ocean or other body of sea water.

The desalination plant 10 preferably includes more than one of the wind turbines 14 to provide redundancy for the periodic servicing and/or maintenance of turbines whilst still being able to produce desalinated water from the remaining operative turbine(s), the wind turbine(s) such as 14 may include a pair of contra-rotating turbine blades coupled to a common shaft/mast structure 19 (see figure The wind turbine 14 may be fixed to its corresponding mast or arranged to swivel about the mast such as 19 for alignment with the wind direction. In a typical installation there may be two wind turbines with associated power generators each capable of producing 5MW for a total power supply to the desalination unit of 10 MW. The mast structure 19 is of a reduced height to provide increased stability and this is possible because of location of the wind turbine(s) such as 12 offshore where they are exposed to relatively unobstructed wind flow.

The floating structure of this example is in the form of a barge 12 which is swing-moored or otherwise anchored to the sea bed via ground tackle or other mooring equipment The floating barge 12 is thus able to self-align with the direction of wind so as to the increase the efficiency of the wind turbine 14. In order to promote this alignment, or adjust for current or tidal flow, the barge 12 may also include a rudder 22 together with selfsteering equipment. The floating structure such as the barge 12 is preferably beamy to provide the necessary windage to swing off the mooring/ground tackle 20 and align with the wind direction. Although not illustrated, the barge 12 may include a pair of propellers mounted on the transom or aft section of the barge 12. The propellers are driven by a hybrid engine (not shown) which is electrically (batteries charged by the wind turbine) or combustion fuel powered. One of the propellers is driven in preference to the other propeller so as to align the barge 12 with the wind direction, particularly under circumstances when the wind and current (or tidal flow) oppose one another. If the relative wind speed is not sufficient to drive the desalination plant, for example below knots, then the production of desalinated water is merely terminated.

The barge 12 can be readily relocated depending on climate change where for example the desalination plant 10 is no longer required in an area which experiences unseasonal rainfall and thus an abundance of fresh or potable water. Conversely, the plant 10 would 203266199_2 6 be located in areas experiencing water shortage as a result of drought. The plant 10 may be of a demountable construction which allows it to be disassembled and shipped or O otherwise transported to another location, for example between countries.

z In this example the desalination unit 16 includes primary treatment means in the form of a reverse-osmosis (RO) filter arrangement 24 operatively coupled to secondary treatment means in the form of an ultraviolet (UV) steriliser 26. The desalination plant 10 also includes a seawater intake line 28 for the provision of seawater from the ocean 18 to the RO filter 24 for the production of desalinated water. A seawater outlet or brine line 30 is provided at a discharge of the RO filter for returning brine to the ocean 18. The seawater intake and the brine outlet lines 28 and 30 are mounted to the barge 12 at its forward and Oaft sections, respectively. In the presence of current or tidal flow this orientation of the seawater intake and brine outlet lines 28 and 30 promotes seawater flow through the desalination unit 16. The desalination plant 10 (see figure 3) may also include a seawater/brine dilution line 31 connected to the brine outlet line 30. This dilution line 31 is effective in reducing the relative salinity of the brine discharge before it is deposited in the ocean 18.

The desalination plant 10 of this embodiment also comprises one or more seawater pumps such as 32 for the pressurisation of seawater to the RO filter 24. The seawater pump 32 is of a hybrid design being either mechanically (or utilising a combustion fuel) or electrically powered by the wind turbine 14. Alternately, the wind turbine 14 may be directly coupled to the seawater pump 32. In a further variant the seawater pump 32 is electrically powered by an alternator or equivalent electrical generator (not shown) which is directly driven by the wind turbine 14.

The desalination plant of this example provides primary treatment in the RO filter 24 and thereafter the filtrate closed to the UV steriliser 26 for the treatment of bacteria and other contaminant micro organisms.

As shown in figure 2, the desalination plant 10 of this embodiment also includes one or more floating reservoirs such as 34 located alongside the floating structure such as the barge 12. The floating reservoir 34 is operatively couple to the desalination unit 16 via desalinated water discharge line 36. The floating reservoirs such as 34 are in this example of a collapsible construction which in an expanded state are designed to contain desalinated water pumped from the desalination unit 16. The collapsible reservoir 34 is fabricated from a flexible material, such as a polymer or plastics material, and is designed to float on the surface or to be slightly submerged alongside the barge 12. The collapsible 203266199_2 7 reservoir 34 of this example is tethered or otherwise rafted alongside the barge 12 via forward and aft lines such as 38 and 40, respectively.

Z As shown in figure 4, the floating reservoirs such as 34A and 34B are designed to be filled with desalinated water and towed onshore via a tug 42 or the like. The reservoirs 34A/B are generally towed in-line with one another. The desalination plant 10 may also be located offshore to take advantage of favourable currents for delivery of the towed reservoirs such as 34A/B to their required onshore destination. For example, the desalination plant would for New South Wales, Australia be located north of Sydney to Stake advantage of the southerly current/set. Although not illustrated, the collapsible reservoirs such as 34 are designed to be emptied of their desalinated water contents and Scollapsed for compact transportation to the floating structure 12.

The wind turbines 14 may also be designed to generate power to be transmitted onshore.

This power generation may partly supplement or wholly substitute for the power generated to drive the seawater pump 32. The power is transmitted onshore via a sub-sea cable or the like (not shown). The plant 10, may be configured to function in three modes, namely: combined desalination and power generation; (ii) desalination only, for example during periods of drought; and (iii) power generation only, for example during periods of peak demand for electricity.

In order to achieve a better understanding of this preferred embodiment of the desalination plant 10, its operation according to another aspect of the invention will now be outlined.

The general steps involved in the production and delivery of desalinated water using the described desalination plant 10 are as follows: 1. The floating structure 12 together with the remainder of the relocatable desalination plant 10 is located offshore in a body of seawater and ideally in an area having favourable wind strengths; 2. The floating reservoir such as 34 is deployed alongside the floating structure or barge 12 and connected to the desalination unit 16 via the discharge line 36; 3. Seawater from the body of water or ocean 18 is provided at an intake of the RO filter 24 via the intake line 28; 203266199_2 8

O

4. The wind turbine 14 drives the hybrid pump 32 for pressurisation of the seawater passing through the RO filter 24 for primary treatment of the seawater; Z 5. The predominantly desalinated seawater is then subjected to secondary treatment at the UV steriliser 26 and discharged into the floating reservoir 34 in its expanded state; 6. Waste brine is discharged from the filtration unit 16 via the brine outlet line and may be diluted in salinity by seawater from a seawater/brine line 31; (N 7. The floating reservoir is filled with desalinated water and then released from the Ofloating structure or barge 12; 8. The floating structure 34 together with its desalinated water contents is towed or otherwise transported onshore for discharge of its contents; and 9. The emptied reservoir is collapsed into a compact state for transporting back to the desalination plant 10 and the preceding steps are repeated.

In some embodiments, the wind turbine may operate with a wave power device for the purpose of power generation and/or driving the hybrid pump 32. The wave power device is adapted to extract energy from the vertical movement of water waves. For example, the wave movement may drive a hydraulic pump which in turn drives the power generator.

Wave movement may also cause the air in a tube immersed vertically and partially in water to flow in and out of the tube, and thereby driving a turbine.

Now that a preferred embodiment of the present invention has been described it will be apparent to those skilled in the art that the desalination plant and method of producing desalinated water from seawater has the following advantages: 1. The desalination plant is driven by the wind and/or wave power which are renewable energy sources and does not produce environmentally destructive greenhouse gas emissions; 2. The desalination plant can be constructed and positioned offshore without the inherent infrastructure requirements of a traditional land-based desalination plant; 3. The desalination plant can be relocated depending on environmental factors including but not limited to levels of rainfall and the associated supply of fresh or potable water, predominant wind speeds and current flows which may be 203266199_2 9 seasonal, wave heights, and the need to reduce brine or salt concentrations in one location; 0 Z 4. The desalination plant together with its floating reservoirs eliminates the need for the usual fixed-plant infrastructure such as power transmission lines and a physical pipeline or similar conduit for transportation of the desalinated water; and The floating structure and desalination plant is designed to provide for selfalignment with the wind to maximise efficiency of the wind turbine.

OThose skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. For example, the desalination plant may include pre-conditioning of the seawater upstream of the RO unit, such as relatively course filters and oil/water separators. Furthermore, the secondary UV treatment may be replaced with other forms of ultra-fine filtration such as a charcoal filter.

The desalination plant may include coarse filter(s) at an inlet/intake of the seawater intake line and/or the seawater/brine dilution line. This coarse filter may take the form of a "trash rack" which periodically can be lifted onto the floating structure for cleaning of retained aquatic species or debris. The specific construction of the desalination plant may vary from that of the preferred embodiment provided the general arrangement and principles are followed insofar as the wind turbine actuates or otherwise drives a desalination unit for the production of desalinated seawater.

All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.

Claims

2. A desalination plant comprising: a floating structure being adapted to be positioned in a body of seawater; a wind turbine mounted to the floating structure; and a desalination unit located at the floating structure and being operatively coupled N to the wind turbine for driving the desalination unit which is adapted to produce Odesalinated water from seawater of the body of seawater.
3. A desalination plant as claimed in claim 2 wherein the floating structure includes a floating vessel or barge which is adapted to be moored offshore in the body of seawater.
4. A desalination plant as claimed in either claim 2 or 3 wherein the desalination plant in its entirety or in part is arranged to be readily relocated. A desalination plant as claimed in any one of claims 3 to 4 wherein the vessel or barge includes a rudder together with self-steering equipment to promote alignment of the vessel or barge with the wind to increase the efficiency of the wind turbine.
6. A desalination plant as claimed in any one of claims 2 to 5 wherein the desalination plant comprises one or more floating reservoirs adapted to locate alongside the floating structure and being operatively coupled to the desalination unit for the storage of desalinated water produced by said unit.
7. A desalination plant as claimed in claim 6 wherein the floating reservoir is of a collapsible construction which is designed to contain desalinated water and be towed in its expanded state whereas in a collapsed state it is designed for compact transportation to the floating structure.
8. A desalination plant as claimed in claim 7 wherein the collapsible reservoir is fabricated from a flexible material.
9. A desalination plant as claimed in any one of claims 2 to 8 wherein the wind turbine is one of a plurality of wind turbines mounted to the floating structure. 203266199_2 11 A desalination plant as claimed in any one of claims 2 to 8 wherein the wind r turbine include a pair of contra-rotating turbine blades dedicated to a common mast of the corresponding wind turbine. z
11. A desalination plant as claimed in any one of claims 2 to 10 wherein the desalination unit includes primary treatment means in the form of a reverse-osmosis (RO) filter arrangement being operatively coupled to secondary treatment means
12. A desalination plant as claimed in claim 11 wherein the secondary treatment q means is in the form of an ultraviolet (UV) steriliser.
13. A desalination plant as claimed in claim 11 wherein the secondary treatment S 10 means is in the form of a charcoal filter or equivalent.
14. A desalination plant as claimed in any one of claims 11 to 13 wherein the desalination unit includes preconditioning units located upstream of the primary treatment means. A desalination plant as claimed in any one of the preceding claims wherein the desalination plant comprises a wave power device operatively coupled to the floating structure for additionally driving the desalination unit.
16. A desalination plant as claimed in either claim 14 or 15 wherein the desalination plant comprises one or more seawater pumps operatively coupled to and powered by the wind turbine for pressurisation of the seawater upstream of the desalination unit.
17. A desalination plant as claimed in claim 16 wherein the seawater pumps are: directly driven by the wind turbine and/or wave power device; (ii) electrically powered by an alternator or equivalent electrical generator which is directly driven by the wind turbine and/or wave power device; or (iii) of a hybrid design being either mechanically or electrically powered.
18. A desalination plant as claimed in claim 17 wherein the electrical generator driven by the wind turbine and/or wave power device is adapted to provide power for transmission remotely.
19. A method of producing desalinated water from seawater, said method comprising the steps of: 203266199_2 12 O providing a desalination plant including a floating structure at which a desalination ri unit is located, the desalination unit being operatively coupled to a wind turbine and/or wave power device; Z locating the desalination plant in a body of seawater; driving the desalination unit utilising energy generated by the wind turbine and/or a wave power device and thereby producing desalinated water from seawater of the body of seawater. A method as claimed in claim 19 wherein the method comprises the step of storing the desalinated water produced in one or more floating reservoirs located alongside the floating structure.
21. A method as claimed in claim 20 wherein the method involves towing the floating reservoirs onshore for discharge of their desalinated water contents.
22. A method as claimed in either claim 20 or 21 wherein the method involves collapsing of the floating reservoirs for shipping and/or other compact transportation to the floating structure for redeployment.
23. A desalination unit substantially as described with reference to and as illustrated in the accompanying figures.
24. A desalination plant substantially as described with reference to and as illustrated in the accompanying figures. Dated: 8 November 2007 Jolyon Emmanuel Nove Patent Attorneys for the Applicant: BLAKE DAWSON PATENT ATTORNEYS