METHOD FOR PROCESSING A LIQUID MEDIUM AND PROCESSING PLANT

Abstract

A method for processing a liquid medium, wherein the medium to be processed is conducted through a liquid circuit and the medium to be processed is heated up in the liquid circuit with the aid of a heat exchanger. A liquid-vapor separation process is carried out in a separating device, and a liquid obtained in the liquid-vapor separation process is conducted into the heat exchanger as a heating medium.

Claims

1.-15. (canceled)

16. A method for processing a liquid medium, the method comprising: conducting the medium to be processed through a liquid circuit, heating the medium to be processed in the liquid circuit with the aid of a heat exchanger, carrying out a liquid-steam separation in a separation device, introducing a liquid which is produced during the liquid-steam separation into the heat exchanger as heating medium, conducting a gaseous carrier medium through an evaporator and a condenser in a cooling circuit, dispersing the medium to be processed in the evaporator by an atomizing device, wherein at least some of the dispersed medium to be processed is evaporated and picked up by the gaseous carrier medium, and condensing at least some of the evaporated medium to be processed, which is picked up by the carrier medium, in the condenser.

17. The method as claimed in claim 16, further comprising: introducing a contaminated liquid from a steam drum in which a first pressure prevails into the separation device, wherein steam is separated from the contaminated liquid during the liquid-steam separation, and introducing the separated steam from the separation device into an element of a steam generator, wherein a second pressure, which is lower than the first pressure, prevails in the element, and the liquid which is produced during the liquid-steam separation is produced from the contaminated liquid.

18. The method as claimed in claim 17, wherein the element of the steam generator, into which the separated steam from the separation device is introduced, is an additional steam drum or an element of the steam generator which is connected downstream to the additional steam drum.

19. The method as claimed in claim 16, wherein the liquid which is produced during the liquid-steam separation is conducted through the heat exchanger and from the heat exchanger is introduced into the liquid circuit, wherein the liquid which is produced during the liquid-steam separation forms at least one part of the medium to be processed.

20. The method as claimed in claim 16, wherein a condensate is produced in a condenser, which condensate is degassed with the aid of a degassing device, and the degassed condensate is introduced into a steam turbine cycle and/or is deionized with the aid of an electro-deionization module.

21. The method as claimed in claim 16, wherein the medium to be processed is heated in the liquid circuit with the aid of an additional heat exchanger, wherein at least some of a process liquid, which flows through a condensate preheater, is directed from the condensate preheater into the additional heat exchanger as heating medium.

22. The method as claimed in claim 16, wherein that part of the medium to be processed which discharges from an evaporator in liquid form is cooled by an additional heat exchanger and is introduced into a buffer tank.

23. A processing plant for processing a liquid medium, comprising: a liquid circuit with a heat exchanger for heating the medium to be processed, a separation device, connected to the heat exchanger, adapted to carry out a liquid-steam separation, wherein a liquid which is produced during the liquid-steam separation is introduced into the heat exchanger as heating medium, a cooling circuit, which is designed with a condenser and an evaporator, the cooling circuit adapted to feed a gaseous carrier medium from the condenser to the evaporator and from the evaporator back again to the condenser, and an atomizing device, wherein the medium to be processed is dispersed in the evaporator by the atomizing device so that at least some of the dispersed medium to be processed evaporates and is picked up by the gaseous carrier medium and at least some of the evaporated medium to be processed, which is picked up by the carrier medium, is condensed in the condenser.

24. The processing plant as claimed in claim 23, wherein the liquid circuit comprises an additional heat exchanger which is adapted to cool a liquid.

25. The processing plant as claimed claim 23, further comprising: a degassing device and an electro-deionization module which is connected to the degassing device.

26. A steam turbine plant, comprising: a processing plant as claimed in claim 23, a steam generator with a first steam drum in which a first pressure prevails, and a second steam drum in which a second, lower pressure prevails, wherein the separation device is connected to the first steam drum and to the second steam drum.

27. The steam turbine plant as claimed in claim 26, further comprising: a condensate preheater, wherein the liquid circuit comprises an additional heat exchanger for heating the medium to be processed and which is connected to the condensate preheater.

28. A method for processing a liquid medium, the method comprising: producing a process liquid for a steam turbine cycle and/or producing a demineralized liquid using the processing plant of claim 23.

29. The method as claimed in claim 16, wherein the gaseous carrier medium comprises air.

30. The method as claimed in claim 17, wherein the contaminated liquid comprises blowdown water.

31. The method as claimed in claim 19, wherein the liquid which is produced during the liquid-steam separation is conducted through the heat exchanger and from the heat exchanger is introduced into a buffer tank.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In the drawing:

[0073] FIG. 1 shows a steam turbine plant having a processing plant for processing a liquid medium; and

[0074] FIG. 2 shows a further steam turbine plant having a processing plant for processing a liquid medium.

DETAILED DESCRIPTION OF INVENTION

[0075] FIG. 1 shows a schematic, simplified view of a steam turbine plant 2. The steam turbine plant 2 has a steam turbine cycle 4. The steam turbine cycle 4 in turn comprises inter alia a three-stage steam turbine 6, a condenser unit 8 and also a steam generator 10.

[0076] The steam generator 10 comprises a condensate preheater 12, wherein the condensate preheater 12, for the sake of better illustration, is shown spatially separated from the other elements of the steam generator 10. The steam generator 10 also comprises a first steam drum 14, a second steam drum 16 and also a third steam drum 18. During operation of the steam turbine plant 2, a higher pressure prevails in the first steam drum 14 (high-pressure drum) than in the second steam drum 16 (intermediate-pressure drum), wherein in the second steam drum 16 higher pressure prevails in turn than in the third steam drum 18 (low-pressure drum).

[0077] The steam generator 10 also has a high-pressure superheater 20, an intermediate-pressure superheater 22 and a low-pressure superheater 24. The high-pressure superheater 20 is associated with the first steam drum 14. The intermediate-pressure superheater 22 is associated with the second steam drum 16 and the low-pressure superheater 24 is associated with the third steam drum 18 accordingly. The respective superheater 20, 22, 24 is connected to the steam drum 14, 16, 18 associated with it. Moreover, the superheaters 20, 22, 24 are connected in each case via a live steam pipe 26 to the steam turbine 6.

[0078] Furthermore, the steam turbine 6 is connected to the condenser unit 8. The condenser unit 8 is connected in turn to the condensate preheater 12. The condensate preheater 12 is also connected via a piping system 27 to the steam drums 14, 16, 18, wherein this piping system 27, for the sake of better clarity, is not shown in its entirety in FIG. 1.

[0079] Moreover, the steam generator 10 has three return pipes 28 which each comprise a temporary liquid storage tank 29 and a pump 30. Each of the three return pipes 28 is connected to one of the three superheaters 20, 22, 24 and also to the steam drum 14, 16, 18 which is associated with the respective superheater 20, 22, 24. The return pipes 28 are used for feeding a (process) liquid, which during operation of the steam turbine plant 2 makes its way out of the respective steam drum 14, 16, 18 into the associated superheater 20, 22, 24, back again into the corresponding steam drum 14, 16, 18.

[0080] Furthermore, the steam turbine plant 2 has a first separation device 32 which is designed as a separation tank and in which a liquid-steam separation can be carried out. The first separation device 32 is connected to the first and to the second steam drum 14, 16 respectively via a connecting pipe 34. The first separation device 32 is also connected via a further connecting pipe 35 to the third steam drum 18. Optionally, the first separation device 32 is connected to a connecting pipe 36 which connects the third steam drum 18 to the low-pressure superheater 24. For the sake of better clarity, the last-mentioned (optional) connection is not shown by way of a figure.

[0081] The steam turbine plant 2 also has a second separation device 38 which is designed as a separation tank and in which a liquid-steam separation can be carried out. The second separation device 38 comprises a cooling trap 40. Connected to the second separation device 38, especially to its cooling trap 40, is a steam discharge pipe 42 via which steam can be exhausted from the second separation device 38 into the atmosphere. Moreover, the second separation device 38 is connected via a connecting pipe 41 to the third steam drum 18.

[0082] The first separation device 32 is also connected to the second separation device 38 via a branch pipe 43 which branches from the additional connecting pipe 35. The first separation device 32 is also connected to the steam discharge pipe 42 via an additional connecting pipe 44 which features a safety valve 45. If a pressure in the first separation device 32 exceeds a predetermined maximum pressure, steam can be released via the additional connecting pipe 44 from the first separation device 32 into the atmosphere.

[0083] Furthermore, the steam turbine plant 2 is equipped with a processing plant 46 for processing a liquid medium. The processing plant 46 comprises a liquid circuit 48 with an evaporator 50, a condenser 52, a feed pump 54 and a buffer tank 56. Furthermore, the liquid circuit 48 comprises a first 3-way valve 58 which is arranged between the evaporator 50 and the buffer tank 56. Connected to this 3-way valve 58 is a disposal pipe 60.

[0084] The liquid circuit 48 also comprises a first heat exchanger 62, a second heat exchanger 64 and also a third heat exchanger 66. All three heat exchangers 62, 64, 66 are designed as liquid-to-liquid heat exchangers. The first heat exchanger 62 is connected on the inlet side to the first separation device 32 and on the outlet side connected to the buffer tank 56. The second heat exchanger 64 on the other hand is connected on the inlet side to an outlet of the condensate preheater 12 and on the outlet side connected to an inlet of the condensate preheater 12. The third heat exchanger 66 is also a component part of a closed cooling system 68.

[0085] Moreover, the previously mentioned elements of the liquid circuit 48 are interconnected via a system of pipes.

[0086] The processing plant 46 also comprises a cooling circuit 70 in which a gaseous carrier medium can circulate. The previously mentioned evaporator 50 and the condenser 52 are not only component parts of the liquid circuit 48 but also component parts of the cooling circuit 70. Moreover, the cooling circuit 70 comprises a fan 72 which is adapted to feed the gaseous carrier medium from the condenser 52 to the evaporator 50 and from the evaporator 50 back again to the condenser 52.

[0087] The evaporator 50 comprises a tank 74 and also an atomizing device 76 which is adapted to disperse or to atomize the medium to be processed in the tank 74. The evaporator 50 also has a carrier-medium admission device 78 which is adapted to admit the gaseous carrier medium into the tank 74 and to disperse it there. The evaporator 50 also has an inlet, not shown by way of a figure, which is provided for introducing an acid into the tank 74.

[0088] Moreover, the processing plant 46 has a degassing device 80, especially a membrane degasser. The degassing device 80 is connected on the inlet side to the condenser 52. On the outlet side, the degassing device 80 is connected via a second 3-way valve 82 to an electro-deionization module 84 which in its turn is connected on the outlet side to a first liquid tank 86. The second 3-way valve 82 is also connected to the condenser unit 8.

[0089] The processing plant 46 also comprises a second liquid tank 88 which contains a liquid to be demineralized, for example drinking water, and is connected to the buffer tank 56.

[0090] During operation of steam turbine plant 2, steam is generated in the steam generator 10 from a process liquid, in the present example from process water. The steam is directed via the live steam pipes 26 into the steam turbine 6 which is driven by the steam.

[0091] The steam from the steam turbine 6 is also directed into the condenser unit 8 in which the steam condenses. The condensate which is formed thereby is fed again to the steam generator 10 and the described process is cyclically repeated.

[0092] Furthermore, during operation of the steam turbine plant 2 contaminants are concentrated in the process liquid so that the steam drums 14, 16, 18 have to be blown down from time to time. For this purpose, the contaminated process liquid, in the present case therefore blowdown water, from the first and the second steam drum 14, 16 is introduced into the first separation device 32. From the third steam drum 18, the contaminated process liquid is introduced into the second separation device 38.

[0093] In the first separation device 32, a liquid-steam separation is carried out. During this, steam is separated from the contaminated process liquid by the contaminated process liquid being expanded in the first separation device 32. Some of the steam from the first separation device 32 is introduced via the additional connecting pipe 35 into the third steam drum. Optionally, some of the steam from the first separation device 32 is introduced into the connecting pipe 36 which connects the low-pressure superheater 24 to the third steam drum 18. From the third steam drum 18 or from the connecting pipe 36 the steam is further directed into the steam turbine 6. In this way, steam is recovered/produced from the contaminated process liquid for driving the steam turbine 6.

[0094] Furthermore, during the liquid-steam separation a liquid is produced. In the case of this liquid it is liquid which remains behind during the liquid-steam separation and which is produced from the contaminated process liquid. The liquid which is produced during the liquid-steam separation is introduced into the first heat exchanger 62 as heating medium and is conducted through said first heat exchanger 62. From the first heat exchanger 62, the liquid is introduced into the buffer tank 56, wherein it forms a part of a liquid medium which is to be processed.

[0095] In the second separation device 38, a liquid-steam separation is also carried out. During this, a liquid is produced in a similar manner. This liquid from the second separation device 38 is introduced directly into the buffer tank 56, wherein it forms another part of the medium to be processed. Steam which is produced during the liquid-steam separation in the second separation device 38 is released via the steam discharge pipe 42 into the atmosphere.

[0096] Also, a lower pressure prevails in the second separation device 38 than in the first separation device 32. Therefore, for example a pressure of several bar can prevail in the first separation device 32, whereas in the second separation device 38 for example atmospheric pressure, or approximately atmospheric pressure, can prevail.

[0097] The medium to be processed is heated in the liquid circuit 48 on the one hand with the aid of the first heat exchanger 62 and on the other hand with the aid of the second heat exchanger 64, wherein some of the process liquid, which flows through the condensate preheater 12, is introduced into the second heat exchanger 64 as heating medium. From the second heat exchanger 64, the process liquid is fed back again into the condensate preheater 12.

[0098] The medium to be processed, upon entering the evaporator 50, is also dispersed or atomized by means of the atomizing device 76 in the tank 74 of the evaporator 50. With the aid of the fan 72, air is conducted through the evaporator 50 as carrier medium against a flow direction along which the medium to be processed flows in the evaporator. Some of the dispersed medium to be processed evaporates in the tank 74, is picked up by the air and conducted by the air into the condenser 52.

[0099] Another part of the medium to be processed, which discharges from the evaporator 50 in liquid formi.e. that part of the medium to be processed which is not evaporated and entrained by the airis cooled by means of the third heat exchanger 66 and then introduced into the buffer tank 56.

[0100] Furthermore, it is provided that in the evaporator 50 an acid is introduced into the liquid circuit 48 so that a forming of carbonates in the medium to be processed is prevented or reduced.

[0101] With the aid of the feed pump 54, the part of the medium to be processed which is introduced into the buffer tank 56 is fed from the buffer tank 56 to the condenser 52. When flow passes through the condenser 52, this part of the medium to be processed cools the evaporated part of the medium to be processed which is picked up by the carrier medium. Consequently, in the condenser 52 a condensate is produced from the medium to be processed.

[0102] The condensate is directed into the degassing device 80 and degassed with the aid of said degassing device 80. The condensate can also be introduced via the second 3-way valve 82 directly into the steam turbine cycle 4, for example into the condenser unit 8, and used as process liquid for the steam turbine cycle 4. Alternatively, the condensate can be deionized after its degassing initially with the aid of the electro-deionization module 84 in order to produce a demineralized liquid (demineralized water) from the condensate. The demineralized liquid can be stored in the first tank 86 and when required can be introduced into the steam turbine cycle 4 as additional liquid (make-up water).

[0103] A residual liquid, which remains behind in the liquid circuit 48 during or after the processing of the medium, can be discharged via the disposal pipe 60 from the liquid circuit 48, for example to a cooling tower or to an external disposal device.

[0104] The above-described method makes it possible to reduce a waste water or dirty water emergence of the steam turbine plant 2. The above-described method also enables an energy-efficient operation of the steam turbine plant 2, especially because thermal energy, which is contained in the contaminated process liquid, can be used to a great extent for processing said contaminated process liquid.

[0105] Furthermore, the processing plant 46 can also be used in another way, which does not have to be coupled to the blowdown of the steam drums 14, 16, 18, for producing a demineralized liquid. The liquid to be demineralized, which is contained in the second tank 88, can be introduced from the second tank 88 into the buffer tank 56. The liquid to be demineralized can then pass through the liquid circuit 48 corresponding to the above-described manner. With this, it is not necessary, however, that a heating medium is introduced into the first heat exchanger 62. That is to say, the first heat exchanger 62 can be used to conduct the liquid to be demineralized in the liquid circuit 48 but without heating it.

[0106] The following description is limited in the main to the differences to the preceding exemplary embodiment described in conjunction with FIG. 1, to which reference is made with regard to consistent features and functions. In the main, the same elements, or elements corresponding to each other, are basically identified by the same designations and mentioned features are not assumed in the following exemplary embodiment without them being described anew.

[0107] FIG. 2 shows a schematic, simplified view of a further steam turbine plant 90.

[0108] The further steam turbine plant 90 differs from the steam turbine plant 2 from FIG. 1 inter alia by the fact that it has no return pipes from the superheaters 20, 22, 24 to the steam drums 14, 14, 18. Instead, the further steam turbine plant 90 has two additional connecting pipes 92 via which the high-pressure superheater 20 and the intermediate-pressure superheater 22 are connected in each case to the first separation device 32. Moreover, the further steam turbine plant 90 has an additional connecting pipe 93 via which the low-pressure superheater 24 is connected to the second separation device 38.

[0109] In the case of the present exemplary embodiment, the contaminated process liquid from the first two steam drums 14, 16 and also from the high-pressure superheater 20 and the intermediate-pressure superheater 22 is introduced into the first separation device 32. The contaminated process liquid from the third steam drum 18 and from the low-pressure superheater 24 is also introduced into the first separation device 32.

[0110] As in the preceding exemplary embodiment, the liquid medium to be processed also consists in this exemplary embodiment of the liquids which are produced during a liquid-steam separation in the first separation device 32 and also during a liquid-steam separation in the second separation device 38 and which are introduced into the liquid circuit 48. In the liquid circuit 48, the medium to be processed is processed corresponding to the manner described further above in conjunction with FIG. 1.

[0111] Although the invention has been fully illustrated and described in detail by means of the preferred exemplary embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention.