GB2513174A

GB2513174A - Pumping apparatus

Info

Publication number: GB2513174A
Application number: GB1307063.6A
Authority: GB
Inventors: Boris Liberman
Original assignee: IDE Technologies Ltd
Current assignee: IDE Technologies Ltd
Priority date: 2013-04-18
Filing date: 2013-04-18
Publication date: 2014-10-22
Also published as: GB201307063D0

Abstract

A pumping apparatus 10 for a water treatment plant comprises a gas supply 15 and at least one gas turbine 11 connected to the gas supply, the gas turbine(s) being connected to drive at least one primary pump 12. A waste heat boiler 26, with a feed water input, has an exhaust gas input 26a which receives exhaust gas from the gas turbine(s) and generates steam from the feed water. The waste heat boiler also has a steam output 25 which is connected to at least one steam turbine 20. The steam turbine(s) is/are connected to drive at least one secondary pump 21 and further have an exhaust steam output 28A. The apparatus further comprises a distillation apparatus 28 which receives the exhaust steam and untreated water 30, wherein the distillation apparatus operates to provide feed water 29 to the waste heat boiler. A method of discharging exhaust gas 35 containing carbon dioxide is also claimed which comprises the steps of receiving a wastewater stream 37 from a water treatment apparatus and combining the wastewater stream with the exhaust gas such that at least a proportion of the carbon dioxide is dissolved in the wastewater stream.

Description

Pumping Apparatus

Technical Field

[0001] The present invention relates to a pumping apparatus for a water treatment system, particularly but not exclusively for a desalination plant, a water treatment system, a method of operating a pumping apparatus, and a method of discharging a waste gas stream.

Background of the Invention

[0002] In an environment in which electricity is temporarily or chronically a scarce resource, for example by virtue of remoteness, vulnerability to natural events or disasters, or otherwise due do an unreliable supply, and where gas is available, gas turbines are known to be effective for the operation of low-pressure pumps. It is known in such circumstances to use a gas turbine to drive a generator to provide electricity to run pumps. It is desirable to maximise the efficiency of such process.

Summary of the Invention

[0003] According to a first aspect of the invention there is provided a pumping apparatus for a water treatment plant, the pumping apparatus comprising a gas supply, at least one gas turbine connected to the gas supply, the at least one gas turbine connected to drive at least one primary pump, a waste heat boiler having a feed water input, the waste heat boiler having an exhaust gas input to receive exhaust gas from the at least one gas turbine and generate steam from the feed water, the waste heat boiler having an steam output, the apparatus further comprising at least one steam turbine, the at least one steam turbine connected to drive at least one secondary pump, the at least one steam turbine being connected to the steam output of the waste heat boiler, the at least one steam turbine further having an exhaust steam output, the apparatus further comprising a distillation apparatus having an exhaust steam connection to receive an exhaust steam stream from the exhaust steam output and an untreated water input to receive an untreated water stream to be treated, the distillation apparatus being operable to generate a feed water stream at a feed water output, the feed water outlet being connected to the feed water input of the waste heat boiler.

[0004] The distillation apparatus may be a multi-effect distillation apparatus.

[0005] The distillation apparatus may be operable to condense the exhaust steam stream to generate at least part of the feed water stream.

[0006] The distillation apparatus may be operable to treat at least part of the untreated water stream to generate at least part of the feed water stream.

[0007] The distillation apparatus may have an untreated water input to receive water to be treated, and an untreated water output.

[0008] The distillation apparatus maybe arranged such that the untreated water is heated by the exhaust steam.

[0009] The waste heat boiler may have an exhaust gas outlet, the exhaust gas outlet being connected to a post-treatment unit, wherein at least a proportion of carbon dioxide in the exhaust gas may be dissolved in water.

[0010] The treatment apparatus may have a waste water inlet to receive waste water from the water treatment plant.

[0011] The untreated water may comprise sea water and the waste water may comprise brine.

[0012] The treatment apparatus may have a discharge outlet to discharge waste water and dissolved carbon dioxide.

[0013] The at least one gas turbine may drive two or more primary pumps.

[0014] The at least one gas turbine may be connected to at least one pump through at least one of a gear train and a clutch.

[0015] The at least one steam turbine may be connected to a secondary pump by at least one of a gear train and a clutch.

[0016] The primary pump may be more powerful than the secondary pump.

[0017] The apparatus may comprise a plurality of gas turbines.

[0018] The apparatus may comprise a plurality of steam turbines.

[0019] According to a second aspect of the invention is provided a water treatment plant comprising at least one water treatment unit and a pump apparatus according to the first aspect of the invention.

[0020] The water treatment plant may comprise a reverse osmosis plant.

[0021] According to a third aspect of the invention there is provided a method of operating a pumping apparatus for a water treatment plant, comprising the steps of supplying gas to at least one gas turbine such that each gas turbine drives at least one primary pump, directing exhaust gas from the gas turbines to a waste heat boiler, supplying feed water to the waste heat boiler, supplying steam from the waste heat boiler to a plurality of steam turbines such that each steam turbine drives at least one secondary pump, and supplying exhaust steam from the steam turbine and untreated water to a distillation apparatus, to provide feed water for the waste heat boiler.

[0022] The method may comprise supplying untreated water to the distillation apparatus and subsequently supplying the warmed untreated water to the water treatment plant.

[0023] The method may comprise the steps of receiving exhaust gas from the waste heat boiler and dissolving at least a portion of the carbon dioxide of the waste gas in a waste water stream.

[0024] The method may comprise the step of supplying waste water from the water treatment plant to provide the waste water stream.

[0025] The untreated water may comprise sea water and the waste water may comprise brine.

[0026] According to a fourth aspect of the invention there is provided a method of discharging an exhaust gas containing carbon dioxide comprising the steps of operating a water treatment apparatus and receiving a waste stream from the water treatment apparatus, combining the waste water stream and the exhaust gas stream such that at least a proportion of the carbon dioxide is dissolved in the waste gas stream, and discharging the waste water stream.

[0027] The waste water stream may comprise brine and the combined waste stream may be discharged at sea.

Brief Description of the Drawings

[0028] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings wherein; [0029] Eig. 1 is a schematic diagram illustrating a pumping apparatus embodying the present invention, and [0030] Fig. 2 is a diagrammatic illustration of an alternative gas turbine and pump for use in the apparatus of Fig. 1.

Detailed Description

[0031] With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

[0032] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated n the drawings. The invention is applicable to other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0033] Referring now to Fig. 1, a pumping apparatus embodying the present invention is generally shown at 10. The apparatus comprises a plurality of gas turbines 11, in the present example six gas turbines. In each gas turbine drives a corresponding primary pump 12 through a reduction gear train 13 and a clutch 14. A gas feed is shown at 15 providing liquid gas, for example liquefied natural gas, liquefied petroleum gas or other suitable fuel, which is supplied to the gas turbines 11. The liquid gas is passed through a temperature control unit 16 which may either heat or cool the supplied liquid gas to a desired temperature. Each of the gas turbines 11 has a gas input 17 which is connected to the gas temperature controller 16. Each gas turbine further has an exhaust gas outlet generally shown at 18.

[0034] The pumping apparatus further comprises a plurality of steam turbines generally shown at 20. Each steam turbine 20 drives at least one secondary pump 21 through a gear train 22 and a clutch 23. Each steam turbine has a steam input 24 which is connected to a steam outlet 25 of a waste heat boiler 26.

[0035] The gear apparatus 13 is necessary as the gas turbines 11 rotate at high speed to efficiently drive the primary pumps 12. Providing a number of smaller turbines with reduction gearing allows for efficient use of the energy supplied in the form of liquid gas and allows relatively more powerful pumps 12 to be used. Similar considerations apply to the secondary pumps 21. Although six gas turbines and eight steam turbines are shown, it will be apparent that the plant may use one or any desired number of gas turbines and steam turbines.

[0036] Waste heat boiler 26 has an exhaust gas input 26a which is connected to the exhaust gas output 18, and comprises a suitable heat exchange system such that heat from the exhaust gases from the gas turbines 11 is used to generate steam from feed water. The generated steam is passed to the steam turbines 20.

[0037] An exhaust steam stream from each steam turbine is supplied through an exhaust steam outlet 27 to a steam connection 28a of a distillation apparatus 28. In the present example, the distillation apparatus 28 preferably comprises a multi-effect distillation apparatus (MED), although any other distillation apparatus may be used as desired. The distillation apparatus 28 further receives water to be treated from an untreated water supply 30. By untreated water is meant water intended to be subsequently supplied to a water treatment plant, for example a desalination plant.

[0038] The distillation apparatus 28 in the present example performs a distillation process in known manner using the heat from the exhaust steam. The exhaust steam from the steam turbines is condensed, to provide a feed water stream. The feed water stream from the distillation apparatus 28 is passed through feed water connection 29 to a feed water input of the waste heat boiler 26.

Pump 29a pumps water through the feed water connection 29.

[0039] Additionally, heat from the exhaust steam is used to at least partially treat the untreated water stream, to provide a treated water stream illustrated at 28b. Some or all of the treated water stream is supplied to the feed water connection 29 as illustrated at 28c, to compensate for losses in the steam cycle of the apparatus. In the alternative, the distillation apparatus may have a single feed water output which receives water from both condensed steam and treated water, and some or all of the single feed may be passed to the waste heat boiler.

[0040] The distillation apparatus further has an output water supply 31. Where the pumping apparatus is provided as part of a water treatment or desalination plant, the output water supply passes untreated water to a suitable water treatment or desalination apparatus, such as a plurality of further distillation systems. The untreated water will be warmed by the distillation apparatus 28.

[0041] Optionally, a heating unit 32 may be provided before the distillation unit 38 to heat the untreated water stream 30. Treatment steps may be performed on the water stream before supplying the water stream to the pumping apparatus 10.

[0042] The waste heat boiler 26 has a cooled exhaust gas output generally shown at 35 which supplies cool exhaust gas to a post-treatment apparatus 36. The post-treatment apparatus 36 receives waste water through a waste water input 37. The exhaust gases from the gas turbines contain a substantial amount of carbon dioxide, and the pre-treatment apparatus is operable to dissolve at least a proportion of the carbon dioxide from the exhaust gas in the waste water stream 37. A discharge outlet 38 allows the combined waste water and carbon dioxide stream to be safely or appropriately disposed of. Depending on the pressure and temperature of the waste water stream 37, the exhaust gas pressure and temperature may be controlled to maximise the proportion of dissolved carbon dioxide and this is carried out at gas control unit 39.

[0043] In the present example, each of the primary pumps 12 are relatively high powered pumps, while the secondary pumps 21 are relatively low powered pumps. Accordingly, in one example 270 MW of energy are supplied as liquid gas at 15, and each of the primary pumps 12 is a 15MW pump.

Approximately 180 MW of power in the form of hot gases at about 400°C are supplied to the waste heat boiler 26. In this example, 160 MW of steam is generated by the waste heat boiler 26 and supplied to the steam turbines 20. The secondary pumps 21 in this example use about 35 MW in total, and relatively cool exhaust steam with about 125 MW is supplied to the distillation apparatus 28. The exhaust steam is condensed in the heat exchange apparatus 28 and the energy transferred to the untreated water stream 30.

[0044] In an alternative configuration shown in figure 2, a more powerful steam turbine is shown at 11' driving a pair of primary pumps 12' through suitable gearing 13' and clutch mechanism 14'. In this example, the gas turbine is a 30MW turbine driving a pair of 15MW pumps. The six turbines 11 of figure 1 could be replaced with three turbines 11', for example.

[0045] In one envisaged application of this invention, the apparatus 10 is used of part of a water treatment apparatus, and in particular a desalination plant, and more particularly a reverse osmosis desalination plant. The primary pumps 11 are used to pressurize the reverse osmosis system, while the secondary pumps 21 may for example comprise intake pumps, circulation pumps, booster pumps and other relatively low powered pumps as required. The untreated water stream in this example is sea water at an example rate 25 m3/s, and the effect of the distillation apparatus 28 is to warm the supply of sea water passed to the reverse osmosis system. The heating element 32 may be any suitable heat exchanger, for example a heat exchanger with brine received from the reverse osmosis plant. As an alternative, the feed water supplied to the waste heat boiler may be wholly or partly distillate from the water treatment apparatus. The distillation apparatus may comprise any part of the water treatment apparatus, and need not simply be limited to condensing the exhaust steam and heating the untreated water stream.

[0046] It will be apparent that any other suitable water treatment or desalination plant may be used in conjunction with this invention. In any case, the waste water stream from the water treatment plant will be a relatively concentrated brine suitable for receiving a relatively high concentration of carbon dioxide.

[0047] In an alternative, it will be apparent that the carbon dioxide dissolved in the waste brine stream need not necessarily come from the gas turbines or an apparatus 10 as shown herein, but from any other plant, such as a nearby power station or other source of exhaust gas.

Advantageously, the waste water stream with dissolved carbon dioxide may be discharged into the sea where the dissolved carbon dioxide is consumed in photosynthesis and converted into oxygen. In the present example, waste brine is at a pressure of about 70 bar at 250°C, and approximately 1300g/m3 of carbon dioxide can be dissolved in the brine after matching the carbon dioxide pressure and temperature to that of the brine.

[0048] In the above description, an embodiment is an example or implementation of the invention.

The various appearances of "one embodiment", "an embodiment" or "some embodiments" do not necessarily all refer to the same embodiments.

[0049] Although various features of the invention may be described in the context of a single embodiment, the features may also be provided separately or in any suitable combination.

Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be implemented in a single embodiment.

[0050] Furthermore, it is to be understood that the invention can be carried out or practiced in various ways and that the invention can be implemented in embodiments other than the ones

outlined in the description above.

[0051] Meanings of technical and scientific terms used herein are to be commonly understood as by one of ordinary skill in the art to which the invention belong, unless otherwise defined.

Claims

Claims: 1. A pumping apparatus for a water treatment plant, the pumping apparatus comprising; a gas supply, at least one gas turbine connected to the gas supply, the at least one gas turbine connected to drive at least one primary pump, a waste heat boiler having a feed water input, the waste heat boiler having an exhaust gas input to receive exhaust gas from the at least one gas turbine and generate steam from the feed water, the waste heat boiler having an steam output, the apparatus further comprising at least one steam turbine, the at least one steam turbine connected to drive at least one secondary pump, the at least one steam turbine being connected to the steam output of the waste heat boiler, the at least one steam turbine further having an exhaust steam output, the apparatus further comprising a distillation apparatus having an exhaust steam connection to receive an exhaust steam stream from the exhaust steam output and an untreated water input to receive an untreated water stream to be treated, the distillation apparatus being operable to generate a feed water stream at a feed water output, the feed water outlet being connected to the feed water input of the waste heat boiler.
2. An apparatus according to claim 1 wherein the distillation apparatus comprises a multi-effect distillation apparatus.
3. An apparatus according to claim 1 or claim 2 wherein the distillation apparatus is operable to condense the exhaust steam stream to generate at least part of the feed water stream.
4. An apparatus according to any one of the preceding claims wherein the distillation apparatus is operable to treat at least part of the untreated water stream to generate at least part of the feed water stream.
5. An apparatus according to any one of the preceding claims, wherein the distillation apparatus has an untreated water output.
6. An apparatus according to claimS wherein the distillation apparatus is arranged such that the untreated water is heated by the exhaust steam.
7. An apparatus according to any one of the preceding claims wherein the waste heat boiler has an exhaust gas outlet, the exhaust gas outlet being connected to a post-treatment unit, wherein at least a proportion of carbon dioxide in the exhaust gas is dissolved in water.
8. An apparatus according to claim 7 wherein the treatment apparatus has a waste water inlet to receive waste water from the water treatment plant.
9. An apparatus according to claim 8 wherein the untreated water comprises sea water and wherein the waste water comprises brine.
10. An apparatus according to any one of claims 7 to 9 wherein the treatment element has a discharge outlet to discharge waste water and dissolved carbon dioxide.
11. An apparatus according to any one of the preceding claims wherein the at least one gas turbines drives two or more primary pumps.
12. An apparatus according to any one of the preceding claims wherein the at least one gas turbine is connected to at least one pump through at least one of a gear train and a clutch.
13. An apparatus according to any one of the preceding claims wherein the at least one steam turbine is connected to a secondary pump by at least one of a gear train and a clutch.
14. An apparatus according to any one of the preceding claims wherein the primary pump is more powerful than the secondary pump.
15. An apparatus according to any one of the preceding claims comprising a plurality of gas turbines.
16. An apparatus according to any one of the preceding claims comprising a plurality of steam turbines.
17. A water treatment plant comprising at least one water treatment unit and a pumping apparatus according to any one of the preceding claims.
18. A water treatment plant according to claim 17 comprising a reverse osmosis plant.
19. A method of operating a pumping apparatus for a water treatment plant, comprising the steps of; supplying gas to at least one gas turbine such that each gas turbine drives at least one primary pump, directing exhaust gas from the gas turbines to a waste heat boiler, supplying feed water to the waste heat boiler, supplying steam from the waste heat boiler to a plurality of steam turbines such that each steam turbine drives at least one secondary pump, and supplying exhaust steam from the steam turbine and untreated water to a distillation apparatus, to provide feed water for the waste heat boiler.
20. A method according to claim 19 comprising supplying the warmed untreated water to the water treatment plant.
21. A method according to any one of claims 17 to 20 comprising the steps of receiving exhaust gas from the waste heat boiler and dissolving at least a portion of the carbon dioxide of the waste gas in a waste water stream.
22. A method according to claim 22 comprising the step of supplying waste water from the water treatment plant to provide the waste water stream.
23. A method according to any one of claims 20 to 22 wherein the untreated water comprises sea water and wherein the waste water comprises brine.
24. A method of discharging an exhaust gas containing carbon dioxide comprising the steps of operating a water treatment apparatus and receiving a waste stream from the water treatment apparatus, combining the waste water stream and the exhaust gas stream such that at least a proportion of the carbon dioxide is dissolved in the waste gas stream, and discharging the waste water stream.
25. A method according to claim 24 wherein the waste water stream comprises brine and wherein the combined waste stream is discharged at sea.