PatentDe  


Dokumentenidentifikation EP1481947 27.09.2007
EP-Veröffentlichungsnummer 0001481947
Titel Vorrichtung zur kombinierten Energieerzeugung und Entsalzung sowie dazugehöriges Verfahren
Anmelder General Electric Co., Schenectady, N.Y., US
Erfinder Mangin, Etienne Marie Luc, 90000 Belfort, FR
Vertreter derzeit kein Vertreter bestellt
DE-Aktenzeichen 602004008147
Vertragsstaaten DE, FR, GB, IT
Sprache des Dokument EN
EP-Anmeldetag 27.05.2004
EP-Aktenzeichen 042531228
EP-Offenlegungsdatum 01.12.2004
EP date of grant 15.08.2007
Veröffentlichungstag im Patentblatt 27.09.2007
IPC-Hauptklasse C02F 1/16(2006.01)A, F, I, 20051017, B, H, EP
IPC-Nebenklasse

Beschreibung[en]

This invention relates generally to power generation and simultaneous desalinization of seawater. Specifically, the invention relates to improving thermal efficiency by using the heat of exhaust gases of a gas turbine to heat water used in the distillation of seawater.

Commercially available desalinization techniques can be classified generally into two categories. The first includes distillation processes that require mainly heat plus some electricity for ancillary equipment. The second includes reverse osmosis processes. In the distillation processes, vapor is produced by heating the seawater close to its boiling temperature and passing it through a series of stages under successively decreasing pressures to induce flashing. The vapor produced is then condensed and cooled as distillate.

In reverse osmosis processes, pure water is forced to pass under pressure through special semi-permeable membranes, while salt is rejected. The pressure differential must be high enough to overcome the natural tendency of water to move from the low salt concentration side of a membrane to the high concentration side, as determined by osmotic pressure.

DE 2 520 936 discloses a process for evaporation and heating using exhaust gas.

This invention is particularly adapted for distillation processes that typically use low pressure steam to heat the seawater as a first step in the distillation process.

When desalinization plants are integrated into gas turbine power plants, they are invariably incorporated as combined cycle power plants that utilize both gas and steam turbines. In combined cycle plants, electricity is produced with high-pressure steam, generated by heat exchange with gas turbine exhaust gases, to run turbines that in turn power electric generators. In a typical case, boilers produce high-pressure steam at about 540°C (1,000°F). As this steam expands in the turbine, its temperature and energy level is reduced. Distillation plants need steam having a temperature of about 120°C (248°F) or below, and this steam can be obtained by extracting lower temperature steam at the low pressure end of the turbine after much of its energy has been used to generate electricity. This low pressure steam is then run through the distillation plant's brine heater, thereby increasing the temperature of the incoming seawater. The condensate from the extracted steam is then returned to the boiler to be reheated.

This invention uses the calories of the gas turbine exhaust gases without having to resort to a complex and expensive installation as in the case of a combined cycle power generation plant. More specifically, a thermal transfer fluid (such as demineralized water) is heated by the gas turbine exhaust gases and used in place of low pressure steam to heat the seawater in the initial step of the distillation process.

In the exemplary embodiment, a boiler is placed in the gas turbine exhaust gas flowpath. A damper upstream of an open cycle exhaust stack permits diversion of the gas turbine exhaust gases into the boiler in a cogeneration mode. The heat of the exhaust gases is transferred via a heat exchanger in the boiler to the thermal transfer liquid (demineralized water) and this liquid is supplied to the desalinization plant where it is passed in heat exchange relationship with the seawater to heat the latter in an otherwise conventional distillation process. After heat exchange, the exhaust gases are released to atmosphere.

The advantages of using hot water as the thermal transfer fluid for the desalinization by distillation include:

  1. a) Simplicity of the boiler and its installation;
  2. b) Low cost compared to an installation that uses steam to heat the seawater;
  3. c) Low pressure of the circulating pump; and
  4. d) No consumption of the thermal transfer fluid.

One disadvantage of using hot water as the thermal transfer fluid for desalinization by distillation is the significant flow of water required in the circuit (for the same transfer of calories), in comparison with the amount of low pressure steam required. However, this disadvantage is outweighed by the advantages noted above.

In its broader aspects, therefore, the invention relates to a method of generating electrical power while simultaneously converting salt water to fresh water comprising: a) supplying exhaust gases from a gas turbine used to generate electrical power to a boiler located downstream of the gas turbine and upstream of a gas turbine exhaust gas stack; b) employing a closed thermal transfer fluid circuit between the boiler and a desalinization plant for recirculating the thermal transfer fluid between a first heat exchange in the boiler and a second heat exchanger in the desalinization plant where the thermal transfer fluid passes in heat exchange relationship with the seawater to thereby heat the seawater as a first step in a distillation process.

In another aspect, the invention relates to a combined gas turbine power generating plant and seawater desalinization plant comprising a gas turbine for generating electrical power and producing exhaust gases to be released to atmosphere; a desalinization plant for removing salt from water; and a closed thermal fluid circuit arranged between an exhaust gas duct of the gas turbine and the desalinization plant, the circuit including a first heat exchanger arranged to heat a thermal transfer fluid with heat from the gas turbine exhaust gases and to supply heated thermal transfer fluid to the desalinization plant for heat exchange with the seawater.

The invention will now be described in connection with the accompanying drawing, which is a schematic flow diagram of a combined gas turbine power generation/desalinization plant in accordance with the exemplary embodiment of the invention.

With reference to the sole Figure, the plant 10 includes a gas turbine 12 of conventional construction, used to produce electrical power. The gas turbine is provided with an exhaust duct 14 leading to a first exhaust stack 16 used when the turbine is operated in an open cycle mode. A damper 18, operated by control 20, is arranged to open or close the inlet to the stack 16. When stack 16 is closed by the damper, the gas turbine will operate in a cogeneration mode, and the exhaust gases will flow into a boiler 22 provided with a heat exchanger 24. The exhaust gases will flow across the heat exchanger and be released to atmosphere via a second exhaust stack 26. Heat from the exhaust gases is transferred to a thermal transfer fluid flowing in the heat exchanger 24, and the heated thermal transfer fluid is then supplied to a desalinization plant 28 via stream 30. One satisfactory thermal transfer fluid is demineralized water, but other suitable liquids may be employed. An accumulator 31 is employed in the stream 30 upstream of the desalinization plant 28 to compensate for the dilatation of the thermal transfer fluid. The plant 28 is an otherwise conventional unit that desalts seawater by a commercially available distillation process. Stream 30 feeds the thermal transfer fluid to heat exchanger 34 in the plant 28. Seawater flows into the desalinization plant 28 via inlet 36 and flows across the heat exchanger 34 to thereby increase the temperature of the seawater to the level required for distillation. After the distillation process is complete, brine is returned to the sea and removed via outlet 32, and fresh water produced by the distillation process is taken from the plant 28 via outlet stream 38.

The thermal transfer fluid, cooled via heat exchange with the seawater, is returned to the boiler 22 via stream 40 and a circulation pump 42. Thus, a closed circuit thermal transfer fluid circuit is formed that includes insulated piping (for streams 30, 40), heat exchangers 24 and 34, the accumulator 31 and pump 42.

The simple and effective installation makes efficient use of the gas turbine exhaust gases for heating seawater in a distillation process.


Anspruch[de]
Verfahren zum Erzeugen elektrischer Energie unter gleichzeitiger Umwandlung von Salzwasser (36) in Süßwasser (38) mit den Schritten: a) Positionieren eines Schiebers (18), um Abgase aus einem ersten Abgaskamin (18) einer zum Erzeugen elektrischer verwendeten Gasturbine zu einem Kessel (22) umzuleiten, der stromab von der Gasturbine und stromauf vor einem zweiten Abgaskamin (26) angeordnet ist; b) Anwenden eines geschlossenen Wärmeübertragungsfluid-Kreislaufs zwischen dem Kessel (22) und einer Entsalzungsanlage (28), um ein Wärmeübertragungsfluid zwischen einem einzelnen Wärmetauscher (24) in dem Kessel (22) und einem weiteren Wärmetauscher (34) in der Entsalzungsanlage (28) zirkulieren zu lassen, wobei das Wärmeübertragungsfluid in eine Wärmetauschbeziehung mit Meerwasser tritt, um dadurch das Meerwasser als einen ersten Schritt in einem Destillationsprozess zu erwärmen; c) Bereitstellen eines Speichers (31) in dem Kreislauf, stromauf vor der Entsalzungsanlage (28); und Abgegeben der Abgase durch den zweiten Abgaskamin (26). Verfahren nach Anspruch 1, wobei die Zirkulation des Wärmeübertragungsfluids durch die Bereitstellung einer Pumpe (42) in dem Kreislauf erzielt wird. Verfahren nach Anspruch 1, wobei das Wärmeübertragungsfluid aus demineralisiertem Wasser besteht. Verfahren nach Anspruch 1, wobei während des Schrittes b) das in dem weiteren Wärmetauscher (34) abgekühlte Wärmeübertragungsfluid zu dem Kessel (22) zur Nacherwärmung durch die Abgase zurückgeführt wird. Kombinierte Gasturbinen-Energieerzeugungsanlage und Meerwasser-Entsalzungsanlage (10), aufweisend: eine Gasturbine (12) zum Erzeugen elektrischer Energie und zum Erzeugen von an die Atmosphäre abzugebenden Abgasen; eine Entsalzungsanlage (28) zum Entfernen von Salz aus dem Meerwasser; und einen geschlossenen Wärmefluidkreislauf, der zwischen einem Abgaskanal der Gasturbine (12) und der Entsalzungsanlage (28) angeordnet ist, wobei der Kreislauf einen Kessel (22) mit nur einem Wärmetauscher (24) enthält, der dafür eingerichtet ist, ein Wärmeübertragungsfluid mit Wärme aus den Abgasen zu erwärmen und das erwärmte Wärmeübertragungsfluid an die Entsalzungsanlage für einen Wärmeaustausch mit dem Meerwasser zu liefern, einen ersten Abgaskamin (16), der stromauf vor dem Kessel (22) angeordnet ist und einen zweiten Abgaskamin (26), der stromab von dem Kessel (22) angeordnet ist, wobei der zweite Abgaskamin (26) dafür eingerichtet ist die Abgase auszugeben, einen Schieber (18), der dafür eingerichtet ist, den Strom der Abgase zwischen dem ersten Abgaskamin (16) und dem Kessel (22) zu steuern; und einen Speicher (31), der in dem Wärmefluidkreislauf stromauf vor der Entsalzungsanlage (28) angeordnet ist. Kombinierte Gasturbinen-Energieerzeugungsanlage und Meerwasser-Entsalzungsanlage nach Anspruch 5, welche ferner eine Pumpe (42) in dem geschlossenen Kreislauf einer Auslassseite der Entsalzungsanlage (28) aufweist, um Wärmeübertragungsfluid zu dem einen Wärmetauscher (24) zurück zu führen.
Anspruch[en]
A method of generating electrical power while simultaneously converting salt water (36) to fresh water (38) comprising: a) positioning a damper (18) to divert exhaust gases from a first exhaust stack (16) of a gas turbine used to generate electrical power to a boiler (22) this is located downstream of the gas turbine and upstream of a second exhaust gas stack (26); b) employing a closed thermal transfer fluid circuit between said boiler (22) and a desalinization plant (28) for recirculating a thermal transfer fluid between a single heat exchanger (24) in said boiler (22) and another heat exchanger (34) in said desalinization plant (28) where said thermal transfer fluid passes in heat exchange relationship with seawater to thereby heat the seawater as a first step in a distillation process c) providing an accumulator (31) in said circuit, upstream of said desalinization plant (28); and releasing the exhaust gases through the second exhaust stack (26). The method of claim 1 wherein recirculating of said thermal transfer fluid is accomplished by providing a pump (42) in said circuit. The method of claim 1 wherein said thermal transfer fluid comprises demineralized water. The method of claim 1 wherein, during step b), thermal heat transfer fluid, cooled in said another heat exchanger (34), is returned to said boiler (22) for re-heating by the exhaust gases. A combined gas turbine power generating plant and seawater desalinization plant (10) comprising: a gas turbine (12) for generating electrical power and producing exhaust gases to be released to atmosphere; a desalinization plant (28) for removing salt from said seawater; and a closed thermal fluid circuit arranged between an exhaust gas duct of said gas turbine (12) and said desalinization plant (28), said circuit including a boiler (22) having a single heat exchanger (24) arranged to heat a thermal transfer fluid with heat from the exhaust gases and to supply heated thermal transfer fluid to said desalinization plant for heat exchange with the seawater, a first exhaust gas stack (16) located upstream of the boiler (22) and a second exhaust stack (26) located downstream of the boiler (22) the second exhaust gas stack (26) arranged to release the exhaust gases, a damper (18) arranged to control flow of the exhaust gases between said first exhaust gas stack (16) and said boiler (22); and an accumulator (31) provided in the thermal fluid circuit upstream of the desalinization plant (28). The combined gas turbine power generating plant and seawater desalinization plant (10) of claim 5, further comprising a pump (42) in said closed circuit on an outlet side of said desalinization plant (28) for returning thermal transfer fluid to said single heat exchanger (24).
Anspruch[fr]
Procédé pour produire de l'électricité tout en convertissant simultanément de l'eau salée (36) en eau douce (38), comprenant des étapes consistant à : a) disposer un registre (18) servant à détourner des gaz d'échappement d'une première cheminée d'échappement (16) d'une turbine à gaz servant à produire de l'électricité vers une chaudière (22) située en aval de la turbine à gaz et en amont d'une seconde cheminée (26) de gaz d'échappement ; b) employer un circuit fermé de fluide de transfert thermique entre ladite chaudière (22) et une installation de dessalement (28) pour faire recirculer un fluide de transfert thermique entre un échangeur de chaleur unique (24) présent dans ladite chaudière (22) et un autre échangeur de chaleur (34) présent dans ladite installation de dessalement (28) où ledit fluide de transfert thermique échange de la chaleur avec de l'eau de mer pour ainsi chauffer l'eau de mer dans le cadre d'une première étape d'un processus de distillation ; c) disposer un accumulateur (31) dans ledit circuit, en amont de ladite installation de dessalement (28) ; et libérer les gaz d'échappement via la seconde cheminée d'échappement (26). Procédé selon la revendication 1, dans lequel la recirculation dudit fluide de transfert thermique s'effectue grâce à la présence d'une pompe (42) dans ledit circuit. Procédé selon la revendication 1, dans lequel ledit fluide de transfert thermique est constitué par de l'eau déminéralisée. Procédé selon la revendication 1, dans lequel, pendant l'étape b), le fluide de transfert thermique, refroidi dans ledit autre échangeur de chaleur (34), est renvoyé dans ladite chaudière (22) pour être réchauffé par les gaz d'échappement. Combinaison (10) d'une centrale électrique à turbine à gaz et d'une installation de dessalement d'eau de mer, comprenant : une turbine à gaz (12) pour produire de l'électricité et produire des gaz d'échappement à libérer dans l'atmosphère ; une installation de dessalement (28) pour dessaler ladite eau de mer ; et un circuit fermé de fluide thermique aménagé entre un conduit de gaz d'échappement de ladite turbine à gaz (12) et ladite installation de dessalement (28), ledit circuit comprenant une chaudière (22) ayant un unique échangeur de chaleur (24) conçu pour chauffer un fluide de transfert thermique par la chaleur extraite des gaz d'échappement et pour fournir un fluide de transfert thermique chauffé à ladite installation de dessalement pour échanger de la chaleur avec l'eau de mer, une première cheminée (16) de gaz d'échappement située en amont de la chaudière (22) et une seconde cheminée d'échappement (26) située en aval de la chaudière (22), la seconde cheminée (26) de gaz d'échappement étant conçue pour libérer les gaz d'échappement, un registre (18) conçu pour réguler l'écoulement des gaz d'échappement entre ladite première cheminée de gaz d'échappement (16) et ladite chaudière (22) ; et un accumulateur (31) disposé dans le circuit de fluide thermique en amont de l'installation de dessalement (28). Combinaison (10) d'une centrale électrique à turbine à gaz et d'une installation de dessalement d'eau de mer selon la revendication 5, comprenant en outre une pompe (42) dans le circuit fermé sur un côté sortie de ladite installation de dessalement (28) pour renvoyer le fluide de transfert thermique dans ledit unique échangeur de chaleur (24).






IPC
A Täglicher Lebensbedarf
B Arbeitsverfahren; Transportieren
C Chemie; Hüttenwesen
D Textilien; Papier
E Bauwesen; Erdbohren; Bergbau
F Maschinenbau; Beleuchtung; Heizung; Waffen; Sprengen
G Physik
H Elektrotechnik

Anmelder
Datum

Patentrecherche

Patent Zeichnungen (PDF)

Copyright © 2008 Patent-De Alle Rechte vorbehalten. eMail: info@patent-de.com