DE2419688A1 - STEAM TURBINE PROCESS WITH ORGANIC MEDIA - Google Patents

Description

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Gebr. Bö hler & Co., Aktiengesellschaft, Vienna

Steam turbine process with organic media

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509832/0255

Organic media have been proposed several times for steam turbine processes and on a trial basis on a small scale also already used. A major difficulty in using suitable organic media, e.g. diphenyl, for this purpose represents the large ratio of specific heat of the liquid phase to the heat of vaporization. It it follows that a Carnotization must be carried out by preheating the liquid in order to obtain acceptable efficiencies. As can be seen from the unusual shape of the T-s diagram, When such organic saturated steam is expanded, superheated steam is produced. The one resulting from this relaxation The temperature is therefore always significantly above the condensation temperature corresponding to the final pressure, i.e. that that for the temperature gradient available to a work process is used relatively poorly. The overheating can, as is known, in a recuperative heat exchanger can be partially used to preheat the liquid organic medium, which leads to * an improvement in the thermal efficiency leads, but are relatively very large heat exchanger surfaces to cool the superheated steam necessary.

The problem is solved according to the invention in that wet steam with such a liquid content is fed to each turbine stage that it reaches at least approximately the saturated steam state after its expansion. Duroh the use of turbine stages with a low degree of reaction, ie with extensive expansion in the diffuser, the steam "* already enters the impeller as saturated steam or with only little moisture, so that the moisture, despite its high initial values, does not cause any problems .

The desired steam humidity in front of the diffuser at the entry of each stage can be achieved, for example

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that in the saturated steam exiting from the previous stage - possibly preheated - feed liquid is injected mechanically. The injection can take place by means of its own nozzle system, with fluidic Reasons this can preferably be accommodated in hollow guide vanes. There are however, there are also other ways of mixing steam and feed liquid to achieve the desired moisture, E.g. atomizing the feed liquid by means of rotating components of the turbine is conceivable. The one in the Wet steam entering the first turbine stage can either be done in an analogous manner or directly through appropriate design generated by the evaporator «

To achieve high levels of efficiency, the temperature gradient available should be in small steps, i.e. processed in many turbine stages. Such an approach is also beneficial for the low speed of sound in the medium, e.g. in diphenyl vapor. By means of individual turbine stages extracted steam can Feed liquid preheated in a manner known per se and thus the thermal efficiency, especially when used organic working medium with high specific heat of the liquid can be increased significantly. Unfortunately for this relatively large heat exchanger surfaces are required due to the low heat transfer coefficients in organic media, albeit much smaller than with the above-mentioned »- preheating by means of superheated steam.

This difficulty with "the Wärmeauötauschflächen. Can be avoided if the preheater are condensers, the Turbinenanzapfdampf is respectively blown into the preheated Speisefiüssigkeit, the former condensed and at the same time the latter heated · As

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the "heat exchanger surface" of mixing condensers is much cheaper to manufacture than of surface condensers, this solution results in significant cost advantages. The multi-stage preheating by means of mixing condensers Pump stages necessary for gradually increasing the pressure of the feed liquid can also to generate the excess liquid pressure required to inject liquid into the saturated steam of the turbine serve, preferably a part of the liquid preheated by means of bleed steam of a turbine stage after passing through the subsequent pump stage for injection into the turbine stage immediately following the tap is used.

In the drawing, the method according to the invention is represented by a schematic sketch and a T-s diagram for Illustrates diphenyl.

In a heat exchanger 11, the working medium of an upstream alkali metal energy conversion process, e.g. potassium vapor, condenses and an organic medium, e.g. diphenyl, evaporates. The heat exchanger is adjusted so that it delivers diphenyl wet steam, that of the first stage 1 of a turbine generally designated 12 is fed. At the end of the first turbine stage 1, the diphenyl vapor reaches the saturated steam state and is liquid diphenyl, which through the line 13 of the inlet side of the diffuser of the second turbine stage is supplied, turned back into wet steam, d '& r am " The end of the second turbine stage is saturated. By renewed supply through line 14- of preheated, liquid diphenyl at the beginning of the third turbine stage 3 is converted into wet steam, which is saturated from this Step exits. This process is repeated with every further turbine stage. · »

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The liquid diphenyl is taken from the feed line 15. At the end of the first turbine stage there is a part of the saturated steam is fed through the line 16 to a mixing condenser 17, where the steam "under further preheating the feed liquid condenses. Line 13 goes behind a pressure pump 18 from the feed line. An analogous arrangement is provided for each turbine stage /.

The exhaust steam is fed to a heat exchanger 19 in which the diphenyl vapor condenses and preheated water from a downstream steam process, preferably an energy conversion process, is evaporated. The condensate is fed to the feed line 15 via a step pump 20 and is gradually heated and brought to a higher pressure.

The energy supplied by the turbine 12 is fed to a consumer 21.

The evaporation of the organic medium can also take place in a boiler. Furthermore, liquids and steam that do not belong to an energy conversion cycle can be used as heating medium. The same applies to the heat exchanger 19

In Fig. 2 part of the Ts diagram for diphenyl is shown. By mixing condensers in heat exchanger 19, the condensed diphenyl using extraction steam and the mixing of capacitors 17 is A'bis B-preheated and vaporized in heat exchanger 11 up to point C. The moisture content is approximately 25% * '"* Then the wet steam is processed in the first turbine stage and reaches the saturated steam state at D. When entering the second turbine stage , the steam is converted into wet steam by mixing with liquid diphenyl ^ which corresponds to point E This process is repeated

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in the remaining of the eight turbine stages, so that finally point F is reached. The exhaust steam is condensed in the heat exchanger 19, so that point A in the diagram is reached again.

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Claims (12)

Claims Steam turbine process with organic media, characterized in that each turbine stage wet steam is supplied with such a liquid content that it after its relaxation at least, approximately reached the saturated steam state. 2. Process according to claim 1, characterized in that the wet steam by supplying liquid medium to Each turbine stage is formed. 3. Process according to claim 2, characterized in that the liquid is injected or atomized. 4 ·. Process according to claim 2 or 3 * characterized in that that the liquid is introduced into the saturated steam of the preceding turbine stage in front of or in the distributor will. 5. Process according to one of claims 1 to 4, characterized in that the turbine stages supplied. liquid medium is preheated. 6. Process according to claim 5 »characterized in that the preheating of the liquid medium by means of a tap * - steam is made. 7. Process according to claim 6, characterized in that the heating of the liquid is carried out in mixing condensers. ' ^{rt /> i} ". *",. * " 8. Process according to claim 6 or 7 * thereby marked .. * <·. ■ · ' ■ · --- · »indicates that the for the introduction of the liquid..in the. Saturated steam, the liquid overpressure required to gradually increase the pressure of the feed liquid necessary pump stages is taken. 509832/0256 9 ". Process according to claim 8, characterized in that a part of the one by means of bleed steam Turbine stage preheated liquid after passing through the subsequent pump stage for introduction into the Tapping is used immediately following turbine stage. 10. Process according to one of claims 1 to 9 »
characterized in that the expansion of the steam in each turbine stage is largely carried out in the diffuser. 11. Process according to one of claims 1 to 10,
characterized in that the heat generated by condensation of the medium of an upstream alkali metal energy conversion process is used to generate the wet steam supplied to the first turbine stage. 12. Process according to one of claims 1 to 11,
characterized in that the organic medium is condensed in an evaporator of a downstream water vapor process. G ebr. ß ö h 1 ε r & Oo \ I Patent Office S 509832 / 025S Empty soap