WO1999067518A1

WO1999067518A1 - Method and system for conditioning the inlet air of a gas turbine system

Info

Publication number: WO1999067518A1
Application number: PCT/EP1999/003781
Authority: WO
Inventors: Christian Appel; Wolfgang Urbanczyk
Original assignee: Steag Encotec Gmbh
Priority date: 1998-06-23
Filing date: 1999-06-01
Publication date: 1999-12-29
Also published as: DE19827961A1; AR018923A1

Abstract

According to the invention a spray nozzle system (5) is positioned in the inlet air duct (1) of a gas turbine in such a way that the spray nozzles are evenly distributed across the cross-section of the air inlet duct (1) according to a defined pattern. By means of the spray nozzle system a hygroscopic brine solution is admixed to the inlet air which in an exothermal reaction withdraws water from said inlet air. Fittings (8) for the recooling of the inlet air are provided for in the sorption chamber (4). The temperature of the dried and recooled air is lowered further in an evaporation humidifier (1) positioned downstream until the saturation temperature is reached. By combining the dehumidification stage with one or more cooling stages it is possible considerably to lower the inlet air temperature, which significantly raises gas turbine performance.

Description

Method and arrangement for conditioning the supply air to a gas turbine plant

The invention relates to a method and an arrangement for conditioning the supply air of a gas turbine system, the supply air being sucked in and cooled from the outside air before it is compressed in the compressor of the gas turbine system.

As is well known, the electrical power and the efficiency of a gas turbine system depend to a not inconsiderable extent on the density of the supply air. The density of the supply air decreases with increasing temperature and is therefore dependent on the outside temperature. Attempts have therefore been made to increase the density of the supply air and thus the electrical power and also the efficiency of the gas turbine system by cooling the intake air. There are limits to such a drop in temperature. In the event of strong fluctuations in outside air temperature, losses in performance and efficiency of the gas turbine system cannot generally be avoided by conventional means.

The invention has for its object to condition the gas turbine supply air in the supply air duct so that the performance and the efficiency of the gas turbine system can be improved.

In solving this problem, the invention is based on the knowledge that the lowering of the supply air temperature to the saturation temperature only with a low relative humidity of the outside air leads to a significant increase in performance and an improvement in the efficiency in the gas turbine could be implemented. At high relative outside air humidity, cooling the supply air has narrow economic limits.

Proceeding from an air conditioning process of the type mentioned at the outset, the solution to the above-mentioned object is characterized in that the supply air is extracted using a sorptive process before the cooling step has ended.

In an arrangement for conditioning the supply air of a gas turbine system, with coolants built into the supply air duct, the invention provides that a sorbent distributor is arranged in an inflow-side section of the supply air duct, which distributes a low-water, hygroscopic sorbent to the supply air in liquid, vaporous and / or provides solid form; and that the coolants are arranged downstream of the sorbent distributor.

Due to the supply air drying that precedes the cooling and / or is associated with the cooling, an extended temperature reduction is made possible, especially when the outside air is high. Air with a low relative moisture content can be cooled to lower temperatures without a condensation effect.

The method according to the invention and the associated arrangement lead to a considerable increase in the electrical power of the gas turbine installation even in the case of large relative outside air humidities.

A preferred further development of the invention consists in that a low-water, hygroscopic medium is distributed in the supply air flow and is acted on the supply air in such a way that the supply air is exothermic tion moisture is withdrawn, and that the supply air is then cooled. Particularly suitable as a hygroscopic medium is a hygroscopic brine solution which is injected into the supply air flow in a uniform distribution and is separated from the supply air downstream after being enriched with water.

The hygroscopic medium enriched with water can then be regenerated in a drying process.

In an alternative procedure, a water portion of the supply air in the supply air duct can be sorbed on a solid sorbent. The sorbent is then transported to a regeneration area and dried. Finally, the low-water sorbent is recirculated into the supply air duct. In an alternative procedure, only partial flows of the gas turbine inlet can be conditioned using the above-mentioned procedure.

Due to the supply air drying and recooling provided according to the invention, use can subsequently be made of the proven spray humidification of the supply air with water to lower the supply air temperature. Spray humidification is a highly effective and technologically reliable option for supply air cooling, but this can only be used if the relative air humidity in the supply air is low. In combination with the sorptive drying and recooling of the supply air, spray humidification of the supply air with water can achieve a relatively large drop in temperature, even if the outside air has a high level of humidity. Therefore, in tropical climates but also in Central European regions with summer outside temperatures and high relative air humidities, a significant increase in the electrical power and also the electrical efficiency of the gas turbine can be achieved compared to gas turbine systems without supply air drying and cooling. Developments of the invention are characterized in the subclaims.

Details and advantages of the invention are explained in more detail below on the basis of exemplary embodiments shown in the drawing. The drawing shows:

1 shows a schematic illustration of a section of the supply air duct of a gas turbine system with the internals provided for supply air conditioning according to an exemplary embodiment of the invention; FIG. 2 shows a schematic view of a desorption chamber which is used for the regeneration of water-rich brine solution and is connected to built-in components from FIG. 1 to form a brine solution circuit; 3 shows a schematic state diagram in the case of sorptive gas turbine supply air cooling using the exemplary embodiment according to FIG. 1; 4 shows another exemplary embodiment of the sorptive gas turbine supply air cooling according to the invention using a solid sorbent and a heat re-cooling rotor in combination with a regeneration chamber; and FIG. 5 shows a schematic, state-of-the-art state change diagram in the sorptive gas turbine supply air cooling according to the exemplary embodiment according to FIG. .

1 schematically shows a section of a supply air duct 1 in which the internals for supply air conditioning are shown schematically according to a first embodiment of the invention.

At the inflow end of the supply air duct 1, outside air passes through a filter 3 into a sorption and recooling chamber. mer 4 one. The filter 3 cleans the incoming outside air. A spray nozzle arrangement 5 is arranged at a distance from the filter 3 in such a way that the individual spray nozzles 50 are distributed as evenly as possible over the cross-section of the duct, so that the jet cones sweep over the entire cross-section of the supply air duct 1. The arrow 51 indicates a nozzle through which the low-water hygroscopic brine solution is supplied to the spray nozzle arrangement 5. The hygroscopic brine solution distributed through the cross section of the feed channel 1 through the spray nozzles 50 extracts moisture, ie water molecules, from the outside air flowing through the chamber 4. This reduces the proportion of vaporous water molecules in the supply air within the chamber 4.

At the downstream end of the sorption chamber 4 is a

Droplet separator 6 is arranged, which separates the water-rich brine solution entrained by the supply air flow and prevents it from escaping from the sorption chamber 4. The brine solution separated on the droplet separator 6 is also drawn off from the sorption chamber 4 by a discharge 7 and fed into the regeneration circuit.

In the exemplary embodiment shown in FIG. 1, a recooling device 8 is arranged in the section between the spray nozzle arrangement 5 and droplet separator 6 and is fed with cooling water via a connection (arrow 81). Heat exchange surfaces are distributed over the cross section of the channel 1, which form a recooling device 8 and recool the supply air stream containing finely divided brine solution. Alternatively, or in addition, the brine solution supplied to the spray nozzles 50 can be cooled. This usually happens outside the supply air duct. When the brine solution is cooled, the recooling device 8 installed in the sorption chamber can be omitted. A section 10 of the supply air duct 1 adjoins the sorption and recooling chamber 4, in which the components of an evaporation fan are installed. This includes a spray humidification distributor 11 which, similar to the spray nozzle arrangement 5, consists of a plurality of spray nozzles 110 distributed over the channel cross section and a water supply connection indicated by arrow 111. In the evaporation humidifier 10, the previously dried and cooled gas turbine inlet t is reduced to near the saturation temperature. At the end of Verdunstungsbef dichterababschnitt 10, a further droplet separator 12 is arranged, which prevents water droplets from the Sprühbefeuc device in the subsequent and not shown in the drawing compressor of the gas turbine.

FIG. 2 schematically illustrates a desorption chamber 9, in which water-rich brine solution drawn off from the hood 7 of FIG. 1 is regenerated and separated as a water-poor solution.

The desorption chamber 9 has a box-shaped or tubular cross section and has a filter 90 at the inflow end. In the exemplary embodiment described, gas turbine exhaust gas serves as the expulsion medium. Alternatively, heated outside air can also be used. The water-rich

Solution (from the brine solution fume cupboard 7) is distributed over the desorption chamber cross section via a distributor 91. In the example described, the desorption chamber is operated at temperatures above 60 ° C., the moisture content of the water-rich brine solution serving as a hygroscopic fluid being reduced. A droplet separator 92 is arranged at the exit of the desorption chamber 9. The brine solution which is also separated off at the droplet separator 92 has a reduced moisture content and is drawn off via a discharge 93 and recirculated to the connection 51 (in FIG. 1) of the spray nozzle arrangement 5. Optionally, can also in the desorption chamber 9 between the components 91 and 92, a heat exchange assembly 94 in the form of a heating coil disposed ^s', can be passed through for example heating water for heating the desorption chamber.

FIG. 3 shows qualitative state diagrams for sorptive gas turbine supply air cooling using the exemplary embodiment according to FIG. 1. In the examples shown in FIG. 3, the outside air has a temperature of approx. 26 ° C. and a humidity of approx. 60%. The spray nozzle arrangement 5 sprays low-water hygroscopic brine solution, which extracts water from the air flow within the sorption chamber 4 under an exothermic reaction. The heat generated by the exothermic reaction during the supply air drying can be dissipated by suitable means, in particular by cooling via the heat exchanger 8 and / or by suitable pre-cooling of the injected brine solution. 3 shows in curve section A a reduction in the supply air water content x [g / kg] from 12 to 9.1 with the supply air temperature remaining the same. At point S, the temperature of the supply air is reduced by spray humidification in the evaporative humidifier to approximately saturation temperature (curve section B), and then the relatively cool supply air is fed to the subsequent gas turbine compressor. After conditioning (curve A-B), the supply air temperature is reduced by almost 10 ° C compared to the outside air temperature.

An increase in the temperature drop can be achieved in that. a stronger recooling is made effective within the sorption and recooling chamber 4. As curve A 'in FIG. 3 shows, practically parallel to the drying step in the sorption and recooling chamber 4, recooling with cold water of 6 ° C. takes place. At point S ', the supply air is reduced on the one hand to a water content of 9.1 g / kg, and on the other hand the supply air temperature is reduced to approx.

Lowered 14 ° C. By subsequent spray humidification (curve B ') the supply air temperature can be reduced to approx. 13 ° C until the saturation temperature is reached with a relatively low water content.

If there is sufficient waste heat available at the gas turbine location at a temperature level higher than 80 ° C, this waste heat can be used to operate a thermal refrigeration machine (e.g. absorption refrigeration system), the cold of which enters the sorption and recooling chamber according to the example in FIG. 3, curve A ', can be involved. As a result, the gas turbine supply air temperature can be further reduced with relatively little effort.

Fig. 4 shows another embodiment of an arrangement for conditioning the gas turbine air, wherein the supply air flow is successively subjected to a sorption step using a solid sorbent and two cooling steps in order to significantly lower the supply air temperature, increase the gas turbine performance accordingly and improve the gas turbine efficiency .

The gas turbine supply air duct section 14 shown schematically in FIG. 4 has a filter 3 that cleans the incoming outside air. The axis of rotation of an adsorption rotor 15 is arranged parallel to the direction of flow of the gas turbine supply air and engages in the interior of the supply air duct 14 in proportion to the area. The adsorption rotor 15 is coated with a hygroscopic medium, for example silica gel, and extracts water from the supply air in an exothermic reaction. In the immediate vicinity of the supply air duct 14 there is a box-shaped or tubular regeneration chamber 19 into which the rotor part saturated with water is rotated and regenerated. This regeneration takes place in that heated air heated in a heating register 20 reduces the moisture content of the hygroscopic medium. The dried air heated in the chamber section 14 behind the adsorption rotor 15 is subsequently recooled by means of a heat recooling rotor 18. The heat recooling rotor 18 has essentially the same dimensions as the adsorption rotor 15 and likewise engages with the area of the supply air duct. The heat extracted from the gas turbine inlet air (via the recooling rotor 18) is used in the exemplary embodiment shown for preheating the outside air in the regeneration duct 19. Spray cooling in an evaporative humidifier 10 follows the recooling in the area of the recooling rotor 18; In this respect, the exemplary embodiment according to FIG. 4 corresponds to that according to FIG. 1.

The qualitative change in state of the gas turbine inlet during conditioning in the exemplary embodiment according to FIG. 4 is shown schematically in the diagram according to FIG. 5.

The outside air is conditioned in three concrete and successive phases.

During a first phase, water is extracted from the outside air in an exothermic reaction, the temperature of the air rising by about 8 ° C. in the example described. In a subsequent cooling step in the heat recooling rotor 18, the supply air in the example described is recooled to approximately the outside temperature, the relatively low water content being maintained. Finally, in the evaporative humidifier 10, the supply air temperature is significantly reduced by spray humidification, namely again by 10 ° C. The supply air conditioning described with the aid of the arrangement according to FIG. 4 results in a supply air temperature reduction of approximately 10 ° C. compared to the outside air temperature. This has a significant increase in performance and Improved efficiency of the downstream gas turbine system.

In a modification of the exemplary embodiment described with reference to FIG. 4, fabric belts which are introduced over a large area into the supply air duct 14 can also be used for the sorptive drying instead of the adsorption rotor. Furthermore, a fluidized bed made of hygroscopic spheres (e.g. silica gel) can be used, which is arranged in the gas turbine supply air duct. As soon as the balls are saturated, the water-loaded balls are regenerated in a separate desorption chamber. Such regeneration can also be carried out continuously in a suitable manner. Both in the course of cooling and recooling the supply air and in the course of regeneration of the sorption medium, heating and cooling energy and gas turbine exhaust gas can be made available as required process energy for the sorptive gas turbine supply air conditioning, to the extent that such energy sources are available cheaply and to the named ones Are usable for purposes.

If the liquid sorption medium is strongly pre-cooled, it may all coolant internals can be dispensed with, which means that the outlay on equipment can be considerably reduced.

Claims

claims

1. A method for conditioning the supply air of a gas turbine system, wherein the supply air is sucked in from the outside air and cooled before it is compressed in the compressor of the gas turbine system, characterized in that the supply air is extracted using a sorptive process before the cooling step is finished.

2. The method according to claim 1, characterized in that a low-water, hygroscopic medium is distributed in the supply air flow and is brought into action in such a way that moisture is removed from the supply air in an exothermic reaction, and that the supply air is then cooled .

3. The method according to claim 2, characterized in that a low-water, hygroscopic liquid, in particular a hygroscopic brine or salt solution, is injected into the supply air stream and is separated downstream of the supply air after water enrichment.

4. The method according to claim 3, characterized in that the water-rich hygroscopic liquid separated from the supply air stream is heat-treated in a desorption chamber, water being expelled, and in that the low-water hygroscopic liquid is then separated from the desorption chamber and circulated into the supply air flow is returned.

5. The method according to claim 4, characterized in that the hygroscopic liquid is treated in the desorption chamber at a temperature above 60 ° C.

6. The method according to claim 5, characterized in that outside air and / or gas turbine exhaust gas flows through the desorption chamber and is heated.

7. The method according to claim 5 or 6, characterized in that the desorption chamber is heated by heat exchange surfaces.

8. The method according to claim 2, characterized in that a water portion of the supply air in the supply air duct is sorbed on a solid sorbent; that the sorbent is then transported to a regeneration area and dried; and that the low-water sorbent is then recirculated into the supply air duct.

9. The method according to claim 8, characterized in that a fabric belt coated with silica gel, a rotor coated with silica gel or a silica gel ball fluidized bed is used as the sorbent.

10. The method according to any one of claims 1 to 9, characterized in that the supply air is cooled by spray moistening up to the vicinity of the saturation temperature.

11. The method according to claim 10, characterized in that the supply air is recooled by heat exchange with a cooling medium.

12. The method according to any one of claims 1 to 11, characterized in that the sorbent is cooled before it is introduced into the supply air duct.

13. The method according to any one of claims 1 to 12, characterized in that the supply air is divided into at least two partial flows and only one of the partial flows is conditioned and that the partial flows are brought together again downstream.

14. Arrangement for conditioning the supply air to a gas turbine system, coolants (8, 11; 18, 11) being installed in the supply air duct (1; 14), characterized in that a sorbent distributor (5; 15) is arranged in an upstream section of the supply air duct , which provides the supply air with a low-water, hygroscopic sorbent in liquid, vaporous and / or solid form; and that the coolants (8, 11; 18, 11) are arranged downstream of the sorbent distributor (5; 15).

15. The arrangement according to claim 14, characterized in that the sorbent distributor is designed as a spray nozzle arrangement (5), the spray nozzles (50) being distributed in a predetermined pattern over the cross section of the supply air duct (1).

16. The arrangement according to claim 15, characterized in that a droplet separator (6) is arranged at a distance downstream of the spray nozzle arrangement (5), which delimits a sorption chamber (4); and that a drain (7) for water-rich sorbent is provided in the sorption chamber.

17. The arrangement according to claim 16, characterized in that coolant (8) are arranged in the sorption chamber (4).

18. The arrangement according to claim 16 or 17, characterized in that a desorption chamber (9) with the sorption central drain (7) of the sorption chamber (4) connected and having means (91, 94) for removing water from the sorbent; and that the desorption chamber is provided with a droplet separator (92) and a drain (93) which is connected to the spray nozzle arrangement (5) of the sorption chamber (4).

19. The arrangement according to claim 14, characterized in that the sorbent distributor is designed as an adsorption rotor (15) which engages on the one hand in the upstream section of the supply air duct (14) and on the other hand in a regeneration area (19), water being removed from the water-rich sorbent in the regeneration area can be .

20. The arrangement according to claim 19, characterized in that the adsorption rotor (15) is coated with a hygroscopic medium.

21. The arrangement according to claim 19 or 20, characterized in that a heat recooling rotor (18) is provided as a coolant downstream of the adsorption rotor (15), which engages on the one hand in the supply air duct (14) and on the other hand in the regeneration area (19).

22. The arrangement according to claim 21, characterized in that a heating register (20) is arranged in the regeneration region (19) between the adsorption rotor (15) and the heat recooling rotor (18).

23. Arrangement according to one of claims 14 to 22, characterized in that the sorbent distributor (5; 15) a recooling device (8; 18) for recooling the dried supply air, an evaporative humidifier (11) are arranged one behind the other in the supply air flow direction.

24. The arrangement according to claim 23, characterized in that the recooling device (8) is a heat exchanger working with cooling water.

25. Arrangement according to one of claims 14 to 24, characterized in that the evaporator of an absorption refrigerator, which is driven by the waste heat of the gas turbine system, is arranged in the supply air duct (1) and serves as a coolant.