DE102011115057A1 - Water treatment plant comprises processing device used for treatment of water, which is supplied to the processing device with a pressure in a desired pressure range, and a pressure stabilizer comprising energy converter - Google Patents

Abstract

Water treatment plant (10) comprises: at least one processing device (11) used for treatment of water, which is supplied to the processing device with a pressure in a desired pressure range; and at least one pressure stabilizer (12) comprising at least one energy converter (13) adapted to hydraulic energy of the water, which is at least partially converted into mechanical energy, when the pressure of the water exceeds an upper limit of desired pressure region and/or to apply additional hydraulic energy when the pressure falls below lower limit of desired pressure range for supplying water. Water treatment plant (10) comprises: at least one processing device (11) used for treatment of water, which is supplied to the processing device with a pressure in a desired pressure range; and at least one pressure stabilizer (12) comprising at least one energy converter (13) adapted to hydraulic energy of the water, which is at least partially converted into mechanical energy, when the pressure of the water exceeds an upper limit of the desired pressure region and/or to apply additional hydraulic energy when the pressure falls below a lower limit of the desired pressure range for supplying the water with pressure in desired pressure range to processing device. Independent claims are also included for: (1) a device (100) comprising at least one water treatment plant, at least one power generation unit having at least one generator driven a turbine and at least one feeding device for supplying water, where the generator is operated by at least some of the feed water and the water treatment plant is adapted for processing at least a portion of the feed water. The energy converter is interconnected between the feeding device and processing device and is mechanically and/or electrically coupled to the generator; and (2) operating the water treatment plant preferably in the device, comprising supplying the processing device with a pressure in the target pressure range by the energy converter, which converts the hydraulic energy of the water at least partly into mechanical energy.

Description

The present invention relates to a water treatment plant, in particular a desalination plant, an arrangement with such a water treatment plant and a power generating device and a corresponding operating method.

State of the art

The process engineering treatment of water - for example, but not exclusively, seawater desalination by reverse osmosis - requires a substantially constant pressure of the water fed in. According to the current state of the art, for example, in reverse osmosis, a constant pressure is required because the membranes used here for desalination hold only very low pressure pulsations.

The desalination of seawater by reverse osmosis is basically known. In reverse osmosis seawater is pressed to overcome the osmotic pressure under high pressure through a suitable semi-permeable membrane, which, among other things, the retained salts are retained. The remaining concentrate (retentate) is continuously removed and replaced by fresh seawater.

Although the present invention will be described in the context of this application primarily with reference to seawater desalination by reverse osmosis, it should be noted that the proposed measures are not limited thereto, but rather can be used in a variety of corresponding methods in which a constant pressure of the Water is required.

Seawater desalination plants powered by wave energy converters and operated according to the principle of reverse osmosis are also known in principle.

Wave energy converters can be deployed on the high seas or near the coast and differ, among other things, in the way in which the energy of the wave motion is extracted. Thus, the use of floats is known in this context, the lifting and lowering movement is implemented accordingly. In another concept, a planar resistance element is attached to the seabed, which is tilted by the wave motion back and forth. It is also possible to use rotors with buoyant rotors in which a buoyancy torque generated on the buoyancy rotors is converted into a rotational movement. An overview of wave energy power plants is for example G. Boyle, "Renewable Energy," 2nd Ed., Oxford University Press, Oxford 2004 ,

The wave-powered seawater desalination is usually carried out in wave power plants with so-called central power generation. In such power plants several wave energy converters are connected to a common pressure line network. In each case, the wave energy converters do not generate electricity directly, but suck in seawater through wave-powered pumps and provide this with appropriate pressure via pressure lines. The pressurized seawater is supplied to a central power generating device and used there only for power generation.

In such wave power plants, a system pressure either - in so-called constant pressure systems - kept constant by means of a corresponding control over long periods or variably adapted to the volume flow provided by the wave energy converter. A disadvantage of a constant pressure system is that losses in the power output can occur in the case of short-term changes in the seaway occurring in practice.

Since, as explained, reverse osmosis devices must be operated at constant pressure, they have not been directly coupled to wave power plants with variable pressure.

Seawater with constant pressure can be provided for example via a seawater hydraulic storage, which is filled by means of suitable pumps. The water taken from the tank under the appropriate pressure is fed directly into the reverse osmosis unit (so-called directly fed reverse osmosis). The pressure must reach at least the membrane pressure required for the reverse osmosis (namely the osmotic pressure of the seawater). Only from a certain wave power can therefore proceed a corresponding reverse osmosis process. Constant pressure systems also have, as mentioned, disadvantages in the degree of absorption, ie the power output from the waves on.

Furthermore, wave power plants with so-called mechanically coupled reverse osmosis devices are known in which the required high pressure is generated by means of a high-pressure pump. The high-pressure pump is mechanically coupled to the shaft of a turbine, which is operated with seawater and drives a generator for generating electricity. In the mechanical coupling, however, arise on the one hand losses to the shaft connected to the engine and the generator and on the other hand in the conversion of mechanical energy into hydraulic energy in the high-pressure pump.

There is therefore a need for an improved use of wave energy for reverse osmosis in corresponding plants.

Disclosure of the invention

Against this background, the present invention proposes a water treatment plant, an arrangement with such a water treatment plant and a power generating device and an associated operating method with the features of the independent claims. Preferred embodiments are the subject of the dependent claims and the following description.

Advantages of the invention

The measures proposed according to the invention are used in a water treatment plant, in particular in a seawater desalination plant which operates by means of reverse osmosis. Such a system may be formed as part of a wave energy power plant with a corresponding power generation device having a turbine and a generator. Such a wave power plant has, as mentioned, in addition to a working by reverse osmosis treatment device via at least one wave energy converter for feeding seawater under pressure, in the context of the present application also more generally referred to as "feeding device". As explained above, wave energy converters in such systems provide variable volume flows depending on the sea state, ie. H. each exploitable energy of the waves. Since a corresponding treatment device opposes a defined resistance to the flow of the water fed in, different pressures result from different volume flows. However, these may fluctuate only to a small extent, especially in reverse osmosis due to the membranes used there. Reverse osmosis systems can offer the possibility, for. B. several membranes as needed in parallel, as explained below. As a result, pressure and flow rate remain constant, but the flow rate changes. The performance of the system changes accordingly.

Therefore, it is proposed to provide at least one pressure stabilizing device to stabilize a pressure of the water provided by the feeding unit.

By "stabilizing" a pressure is meant any adjustment in which the pressure is reduced when it exceeds a setpoint and / or the pressure is increased when it falls below a setpoint. The permissible range of corresponding pressures ranges, for example, from 30 bar to 160 bar at a target pressure of 80 bar (referred to in this application as "target pressure range"). The pressures depend on the salinity of the used seawater. The pressure must always be above the osmotic pressure. The upper pressure limit is due to the component.

Therefore, a corresponding pressure stabilizing means will reduce the pressure before the conditioner when it exceeds said upper limit and increase the pressure when it falls below said lower limit.

For this purpose, such a stabilization device according to the invention an energy converter, which is adapted either to reduce the pressure hydraulic energy of the injected water partially convert into mechanical energy, or to pressurize the injected water to increase the pressure with additional hydraulic energy. Advantageously, the energy converter is designed as a hydraulic pump-motor unit. The energy converter can mechanically, d. H. For example, be coupled by means of a shaft with a generator for generating electricity. The pump-motor unit acts either as an additional resistance in the flow path of the water before the treatment device or builds there a corresponding additional pressure. When coupled to the generator, an additional generator torque can be generated from the hydraulic energy of the water fed in via the pump-motor unit, or - in the case of motor operation of the generator - a motor torque can be converted into hydraulic energy for acting on the supplied water.

The present invention makes it possible in a particularly advantageous manner, a desalination of seawater even in plants that do not provide constant pressure. As a result, an improved yield of wave energy can be achieved in corresponding plants. In particular, the proposed energy converter can supply or remove mechanical power as a function of the hydraulic power provided by the wave energy converter. In contrast to mechanically coupled reverse osmosis, as explained above, the system proposed according to the invention requires only one mechanical transducer to provide a constant pressure. The system already has the pressure of the wave energy converter so that only one differential pressure has to be bridged. So it is only supplied or removed hydraulic power. The hydraulic power does not have to be as in the prior art (see below 1 ), first into mechanical power and then back into hydraulic power.

A processing device is advantageously followed by a further energy converter, which is provided for converting remaining hydraulic power into mechanical energy, and, when coupled with a generator, into electrical power. When using a reverse osmosis device, such a further energy converter is arranged in the retentate stream. Further, in a corresponding water treatment plant, a buffer memory may be provided, for example in the form of a hydraulic pressure accumulator, which ensures a compensation of at least short-term pressure fluctuations. Such can z. B. a continuous seawater desalination even during brief lulls done. Power generation by means of an energy converter downstream of the processing device is also possible when a buffer store is provided during brief lulls.

Particularly advantageous in the proposed measures according to the invention is when they are used in a wave power plant with associated reverse osmosis device. As a result, the disadvantages of constant pressure systems can be avoided in the wave power plant, which leads to a significantly improved degree of absorption of the wave energy converter. Load peaks can each be intercepted and buffered in the buffer memory of a reverse osmosis device. Operation of the reverse osmosis process and / or power generation from the stored pressure energy of the seawater are possible.

The invention is illustrated schematically with reference to an embodiment in the drawing and will be described in detail below with reference to the drawing.

figure description

1 shows a wave power plant with seawater desalination device according to the prior art in a highly schematic representation.

2 shows a wave power plant with seawater desalination device according to an embodiment of the invention in a highly schematic representation.

In 1 a wave power plant with seawater desalination device according to the prior art with its essential components is shown very schematically.

The wave power plant includes a water treatment facility 11 , z. B. in the form of a reverse osmosis device with a likewise highly schematically illustrated semipermeable membrane 11 , Reverse osmosis devices commonly used in such systems include, as known to those skilled in the art, cartridge-type assemblies in the form of membrane stacks. By means of the water treatment device 11 Freshwater S is produced. Concentrated retentate is removed (not shown).

The water treatment device 11 is by means of a high pressure pump 26 over a line 97 sucked seawater A supplied under high pressure. The pressure is adjusted by means of a pump control, not shown. The high pressure pump 26 is from a motor 25 driven. The motor in turn is by means of a shaft 24 with a turbine 21 , For example, a Pelton turbine coupled. The turbine 21 charged next to the engine 25 also a generator 22 with a corresponding moment that generates electricity accordingly.

The turbine 21 is operated by means of water A ', via at least one feed device 30 , in the present case at least one wave energy converter, via a line 98 under pressure of the turbine 21 supplied and discharged as wastewater W.

It is known (but not shown) to use a pressure exchanger which uses the pressure of the retentate to assist the high-pressure pump.

As from the representation of 1 For the skilled person immediately apparent, must to generate the high pressure by means of the high-pressure pump 26 , and thus for desalination by means of the water treatment device 11 , always a turbine moment first in a mechanical moment of the shaft 24 be converted, regardless of whether possibly already water A 'on the at least one feed device 30 provided with appropriate pressure. The moment of the wave 24 must then again by means of the high-pressure pump 26 be implemented in hydraulic power. Corresponding losses of the respective components are unavoidable.

In 2 a wave power plant with seawater desalination device according to an embodiment of the invention is shown in a highly schematic and total with 100 designated.

The appropriate arrangement 100 includes a water treatment plant 10 and one of these associated power generating device 20 , Furthermore, at least one feed device 30 provided by means of which water A in the water treatment plant 10 can be fed. The at least one feed device 30 may in particular comprise at least one wave energy converter, as explained above. As already explained above, by the at least one feed device 30 Water with variable pressure in the water treatment plant 10 fed.

Again, one, z. B. formed as a reverse osmosis device processing device 11 provided that a corresponding membrane 11 ' has and is set up for processing fed water A. In this case, an interconnection of the modules within the processing device 11 respectively. By controlling the parallel connection of several modules, eg. As the activated carbon filter used, ultrafiltration equipment and reverse osmosis membranes, pressure and flow rate can be kept equal, while the flow rate, due to external influences fluctuates. To provide a constant pressure for the treatment device 11 Here is an energy converter in the form of a pump-motor unit 13 having stabilizing device 12 provided, which is adapted to a pressure of the fed water A to the required input pressure of the treatment device 11 adjust.

Water A is for this purpose by means of at least one feed device 30 via a pressure line 1 fed in under pressure. Part of the water A is over another line 2 the pump-motor unit 13 fed. The pump-motor unit 13 works according to the pressure of the over the further line 2 supplied water A. The coupling of the pump-motor unit 13 can also be done electrically. With this type of interconnection, the power loss may be slightly higher, but the power distribution is much more variable.

In the event that the pressure of the at least one feed device 30 fed water A is greater than that for the treatment device 11 required pressure, excess hydraulic power is converted into mechanical power and can be transmitted through a generator shaft 24 into a generator 22 be initiated. In this way, hydraulic power peaks, as through the at least one feed device 30 be deployed, intercepted and used for power production. Is the pressure of the at least one feed device 30 fed water A less than that for the treatment device 11 required pressure, it is possible to take additional power from the electrical network, the generator 22 To operate motor, and in this way to maintain a reverse osmosis process.

Regardless of whether by means of the pump-motor unit 13 Power is removed or supplied, the water A passes through a pipe 3 to the processing device 11 and is processed there accordingly. Treated fresh water S can be taken from the plant, concentrated retentate can be sent via a pipe 4 be dissipated.

A downstream of the treatment device 11 in the pipe 4 present retentate pressure, more generally, a pressure of the waste water of a corresponding treatment device 11 , can be used to, by means of another energy converter 23 , For example, a corresponding hydraulic motor to recover energy. Also the other energy converter 23 can with the generator shaft 24 be coupled.

One too with the generator 22 coupled turbine 21 , z. B. a Pelton turbine, is in a so-called primary circuit by means of a line 6 from the at least one feed device 30 also fed and operated with water A.

One or more buffers 14 . 40 may be provided and serve as capacity (s) within the network (s). A first buffer memory 14 is in this case as capacity within the constant pressure network, that is to supply the processing device 11 provided network. This allows, in the case of a short-term sinking of the hydraulic power, z. B. a wave energy converter in the at least one feed device 30 , A corresponding turbine further by a retentate of the treatment device 11 to operate power generation. The cache 14 thus serves as a capacity for occurring pressure fluctuations. The energy converter 13 uses the in the pressure line 1 upcoming, z. B. generated by a wave energy converter pressure, if any, and transforms it to that for the processing device 11 required pressure or pressure range.

Another buffer 40 serves to buffer fluctuations in the turbine 21 supplying piping system.

The hydraulic units used in each case can be adjustment units and / or designed as constant units. A rotational speed of a turbine designed as an adjusting unit 21 , z. As a free-jet turbine, it can be changed, for example, via a downstream frequency converter. Between the stabilizer 12 and one or more energy converters 13 . 23 For example, flywheels in the form of flywheels may be provided for smoothing torque peaks. Between the energy converter 23 for converting the hydraulic energy of the retentate from the treatment device 11 is used, and the turbine 21 a coupling can be provided. A cache 40 can be provided as a pulsation damper to reduce short-term pressure peaks. The processing device 11 can also be bridged and an energy converter 21 . 23 operated directly with a buffer storage water, whereby a power generation is ensured even in short-term lulls.

In the table below are other ways to generate the required pressure for the treatment device ("generating feed pressure"), the use of a pressure in the retentate ("use retentate"), so the above-mentioned line 4 downstream of the treatment device, the connection and the use of a power in the primary circuit ("primary circuit use"), ie the line 6 , stated. With "supply and discharge P _mech " or "discharge P _mech " is the type of supply and / or removal of the hydraulic power, ie the implementation in the mechanical performance or from this, indicated, with n denotes a speed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• G. Boyle, "Renewable Energy", 2nd ed., Oxford University Press, Oxford 2004 [0006]

Claims (11)

Water treatment plant ( 10 ) with at least one processing device ( 11 ) for the treatment of water (A), that of the treatment facility ( 11 ) is supplied with a pressure in a desired pressure range is set up, characterized in that the water treatment plant ( 10 ) at least one pressure stabilization device ( 12 ) with at least one energy converter ( 13 ), which is adapted to at least partially convert hydraulic energy of the water (A) into mechanical energy when the pressure of the water (A) exceeds an upper limit of the target pressure range and / or to pressurize it with additional hydraulic energy when the pressure Lower limit of the target pressure range falls below the processing unit ( 11 ) to supply the water (A) with a pressure in the target pressure range. Water treatment plant ( 10 ) according to claim 1, wherein the at least one energy converter ( 13 ) is designed as a hydraulic pump-motor unit. Water treatment plant ( 10 ) according to claim 1 or 2, wherein the at least one processing device ( 11 ) is designed as a reverse osmosis device. Water treatment plant ( 10 ) according to one of the preceding claims, which is adapted for the treatment of water (A) with a pressure in a desired pressure range of 30 to 160 bar. Arrangement ( 100 ) with at least one water treatment plant ( 10 ) according to one of the preceding claims, at least one power generating device ( 20 ) with at least one with a turbine ( 21 ) operated generator ( 22 ) and at least one feed device ( 30 ) for feeding water (A), wherein the generator ( 22 ) by means of at least a portion of the injected water (A) operable and the water treatment plant ( 10 ) is arranged for the treatment of at least part of the supplied water (A), wherein the energy converter ( 13 ) between the feeding device ( 30 ) and the processing device ( 11 ) and mechanically and / or electrically connected to the generator ( 22 ) can be coupled. Arrangement ( 100 ) according to claim 5, wherein at least one feed device ( 30 ) has at least one wave energy converter. Arrangement ( 100 ) according to one of claims 5 or 6, wherein at least one further, the processing device ( 11 ) downstream energy converter ( 23 ) is provided for converting hydraulic energy of the water (A) into mechanical energy. Arrangement ( 100 ) according to one of claims 5 to 7, comprising at least one buffer memory ( 14 . 40 ) for fed water (A). Arrangement ( 100 ) according to one of claims 5 to 8, which is designed as a wave energy power plant with seawater desalination plant. Procedure ( 100 ) for operating a water treatment plant ( 10 ) according to one of claims 1 to 5, in particular in an arrangement according to one of claims 6 to 9, in which water (A) of the treatment device ( 11 ) is supplied with a pressure in a desired pressure range by means of the energy converter ( 13 ) Hydraulic energy of the water (A) is at least partially converted into mechanical energy when a pressure of the water (A) exceeds an upper limit of the target pressure range, and / or this is acted upon by hydraulic energy, when the pressure falls below a lower limit of the target pressure range. Procedure ( 100 ), in particular according to claim 10, for stabilizing a fluid pressure by means of an energy converter ( 13 ) in the form of a pump-motor unit, in which hydraulic energy of the fluid is at least partially converted into mechanical power when a desired pressure is exceeded, and when the hydraulic pressure drops below a desired pressure, the fluid is subjected to hydraulic power.

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