EP2435678A1

EP2435678A1 - Intake air temperature control device and a method for operating an intake air temperature control device

Info

Publication number: EP2435678A1
Application number: EP10724002A
Authority: EP
Inventors: Erich Schmid; Daniel Hofmann; Michael SCHÖTTLER
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2009-05-28
Filing date: 2010-05-25
Publication date: 2012-04-04
Also published as: EP2256316A1; US20120067057A1; CN102449288B; WO2010136454A1; CN102449288A; KR20120026569A

Abstract

The invention relates to an intake air temperature control device (18) comprising a heat exchanger (12) which is connected at one side into an intake air line (6) and which is connected at the other side into a circuit (13) of an intake air preheating system (2), wherein a store (19) for a fluid for heat transfer can be thermally connected to the circuit (13). The invention also relates to a method for operating an intake air temperature control device (18).

Description

description

Ansauglufttemperiereinrichtung and a method for operating a Ansauglufttemperiereinrichtung

The invention relates to a Ansauglufttemperiereinrichtung, in particular for a gas and steam turbine plant, and a method for operating such a device and in particular relates to an improved peak load operation of a combined cycle power plant.

It is known that the performance of gas and steam turbine plants, etc. is dependent on the intake air temperature of the gas turbine and that at high ambient temperature, a lower power is generated. In hot countries, depending on the time of day, there are peaks in power consumption, which may include: caused by the increased power requirements for refrigeration units. This high consumption leads in electricity markets with price formation according to supply and demand, especially in the afternoon to high electricity prices. Although at night, a higher output of the gas and steam turbine plant would be possible, but both the electricity demand and the electricity price are usually low.

To counter this problem, for example, at peak load times, the intake air can be cooled by evaporative cooling in front of the gas turbine. The effectiveness of this method, however, depends on the humidity and only leads to a limited increase in performance. Also disadvantageous are the associated water requirements or water losses.

Alternatively, the power penalty due to high ambient temperatures in the gas turbine can be compensated by a heat recovery steam generator auxiliary firing. The disadvantages of this solution are the additional production costs, the reduction in efficiency and the oversizing of the water-steam cycle, the steam turbine and, if there is no single-shaft system, the steam turbine generator. Basically, performance losses can of course be compensated by the use of reserve power. Additional gas and steam turbine plant and aggregates, however, lead to high costs with a comparatively short service life.

Finally, the intake air of the gas turbine can be cooled by conventional refrigerators. However, the chillers themselves use a lot of electricity. The process does not lead to a noticeable increase in performance.

The object of the invention is to improve the peak load operation of a gas turbine plant, in particular a gas and steam turbine plant, so that a high performance is achieved with high efficiency.

According to the invention this object is achieved by the device according to claim 1 and the method according to claim 11. Advantageous developments of the invention are defined in the respective dependent claims.

In the case of an intake air temperature control device comprising a heat exchanger which is connected on the one hand into an intake air line and on the other hand is connected in a circuit of an intake air preheating system, a reservoir for a fluid for heat transfer can be thermally connected to the circuit, the following is achieved:

The intake air preheating system (Air Preheater System = APH) is already available in many systems in current and future gas and steam turbine systems because of the partial load reduction at night and at the weekend (CO problem). A fluid is now made available via the reservoir, with which the temperature of the intake air can be influenced via the already existing intake air preheating system. The intake air preheating system can also be used for cooling in the same way as the air is preheated. Advantageously, the memory is thermally connectable to the circuit by a first fluid line branches off from the memory and opens into the circuit and a second fluid line branches off the circuit and opens into the memory. The fluid is in this case added directly into the intake air preheating system and can influence the temperature of the intake air for a gas turbine via the heat exchanger of the intake air preheating system.

Alternatively, a heat exchanger is connected in the circuit and connected via a first and a second fluid line to the memory. In this case, the fluid forms a separate circuit with storage and heat exchanger and the circuit of the intake air preheating remains unchanged.

The heated by the heat exchange with the intake air fluid may conveniently be cooled again by an air-fluid heat exchanger on the one hand in a storage circuit and on the other hand connected to a branching off of a compressor air line, the storage circuit, the memory, one between the first and the second fluid line connected third fluid line, and portions of the first and second fluid line from the memory to the third fluid line comprises.

For this purpose, at least one further heat exchanger for cooling the air in the branching off of the compressor air duct in the flow direction of the air is preferably connected upstream of the air-fluid heat exchanger. The further heat exchanger can be connected, for example, in the water-steam cycle of a gas and steam turbine plant and used for warming feed water.

For further cooling of the compressor air, a pressure-reducing valve is advantageously connected between the further heat exchanger and the air-fluid heat exchanger in the air line. Alternatively, advantageously, an air expansion turbine can be connected between the further heat exchanger and the air-fluid heat exchanger in the air line.

In an advantageous embodiment of the invention, the heat transfer fluid is a mixture of water and cryoprotectant (eg, glycol or ethanol). By a large heat transfer coefficient and the lowering of the freezing point of the water by the antifreeze a mixture of water and antifreeze is particularly suitable for such application.

Advantageously, the Ansauglufttemperiereinrichtung is part of a gas turbine plant or a gas and steam turbine nenanlage.

In the inventive method for operating an Ansauglufttemperiereinrichtung with an intake air preheating system, a fluid for heat transfer from a memory is emptied and fed to the intake air preheating system for changing the temperature of an intake air.

To regenerate the fluid, compressor air is advantageously used, which itself must first be cooled. It is advantageous if compressed compressor air is cooled in heat exchange with water, for example medium pressure or low pressure feed water of a water-steam cycle of a gas and steam turbine plant.

Furthermore, it is advantageous if, for further cooling, a throttle relaxes the cooled compressor air.

Alternatively, it may also be expedient to relax the compressor air in an expansion turbine.

For the device according to the invention or the method according to the invention, only low modalities are present at a gas and steam turbine installation with an intake air preheating system which is present anyway. Depending on whether the heat transfer fluid is integrated directly into the intake air preheating system or via a heat exchanger, this requires additional heat exchanger.

Furthermore, in the nighttime usually the Stormbedarf and also the Stromerlös least. For utilization of the gas and steam turbine plant, part of the energy generated can now be converted into cold fluid, for example, and stored, which provides additional power output during the day with high electricity revenue. Thus, the gas and steam turbine plant is similar to a storage power plant, which consumes electricity at low electricity prices and can generate additional electricity at high electricity revenue, without changing the nominal power. Depending on the design of the systems, the cooling of the intake air, eg from approx. +40 ⁰ C to +10 ⁰ C, increases the output by 15-20%.

The technical equipment effort is less than with a solution with conventional refrigeration machines and also the efficiency of the system (in particular with expansion turbine) is significantly higher. In addition to the previous tasks (CO avoidance at partial load, low load), the intake air preheating system, which is usually required in any case, is also used for cooling at high outside temperatures and can therefore be used much more economically.

The device can significantly reduce the need for auxiliary steam for the so-called anti-icing operation of the gas turbine even in winter or generally at low ambient temperatures by hot water storage, wherein the memory is also discharged via the intake air preheating system. A combination of low outside temperatures and high relative humidity values results in a greatly increased risk of icing up the intake system and the entire gas turbine. The risks include icing of the filters and the consequent reduction or blocking of the air supply. The former leads to reduced performance, the latter indicates standstill of the plant. Far more problematic, however, are ice crystals or drops that penetrate into the turbine and come into contact with the blades of the turbine. This means in the best case increased wear, in the worst case, the premature destruction of the system. Therefore, it is technically and economically of utmost importance to effectively prevent icing. The addition of antifreeze prevents freezing of the water during heat exchange with cold intake air. The required for heating the mixture of water and antifreeze

Heat is taken, for example, from the steam systems of the water-steam circuit of a gas and steam turbine plant.

In addition to being used in anti-icing operation, the stored hot water can also significantly increase plant efficiency during part-load operation.

The heating and cooling of buildings and room units can be done with the help of cold or hot water storage in a simple manner. Depending on the design and operation of the memory can also be cooled and heated in parallel if necessary.

The invention will be explained in more detail by way of example with reference to the drawings. Shown schematically and not to scale:

FIG. 1 shows a gas turbine plant and a current gas turbine intake air preheating system,

FIG. 2 shows an intake air tempering device with direct thermal coupling by feeding the fluid from the reservoir into the intake air preheating system,

FIG. 3 shows an intake air tempering device with indirect thermal coupling via a heat exchanger, FIG. 4 shows the production of cold fluid with throttle valve in the compressor air line,

FIG. 5 shows the generation of cold fluid with a relaxation turbine in the compressor air line,

Figure 6, the integration of the production of cold fluid in the water-steam cycle of a gas and steam turbine plant and

Figure 7 shows the use of the memory of Ansauglufttemperier- device as a heat storage.

1 shows schematically and by way of example a gas turbine plant 1 and a current gas turbine intake air preheating system 2 of a gas and steam turbine plant. The gas turbine plant 1 is equipped with a gas turbine 3, a compressor 4 and at least one combustion chamber 5 connected between the compressor 4 and the gas turbine 3. By means of the compressor 4, fresh air is sucked in via the intake air line 6, compressed and fed via the fresh air line 7 to one or more burners 8 of the combustion chamber 5. The supplied air is mixed with supplied via a fuel line 9 liquid or gaseous fuel and ignited the mixture. The resulting combustion exhaust gases form the working medium of the gas turbine plant 1, which is supplied to the gas turbine 3, where it performs work under relaxation and drives a coupled to the gas turbine 3 shaft 10. The shaft 10 is coupled with the gas turbine 3 and with the air compressor 4 and a generator 11 to drive them.

As a result of the preheating of the intake air, the total mass flow of fuel-air mixture which can be supplied to the gas turbine 3 per unit time is reduced so that the maximum output achievable by the gas turbine plant 1 is less than when the intake air is not preheated. However, when preheating the intake air decreases by supplying the heat, the fuel consumption stronger than the maximum achievable power output, so that the overall efficiency increases.

The intake air preheating system 2 consists of a heat exchanger 12 which is connected on the one hand to the intake air line 6 and, on the other hand, is connected to a circuit 13 of the intake air preheating system 2 in which a fluid is circulated by a circulating pump 14. Another heat exchanger 15, which is connected to the circuit 13 on the secondary side, is connected on the primary side to a water-steam circuit 16 with a pump 17. A steam flowing through the further heat exchanger 15 heats the circulating fluid and condenses in the process. The resulting condensate is removed via the pump 17. The heated fluid in turn discharges the absorbed heat in the heat exchanger 12 to the intake air in the intake air line 6.

Figure 2 shows a Ansauglufttemperiereinrichtung 18 according to a first embodiment of the invention with direct feed of a cold fluid in the intake air preheating system 2. The fluid may be, for example, water, an antifreeze or a mixture of water and antifreeze. In this case, the cold fluid is fed directly into the intake air preheating system 2 from a reservoir 19 via a first fluid line 20. The cold fluid passes through a bypass 21 on the heat exchanger 15, which usually heats the fluid of the intake air preheating system 2, and passes to the heat exchanger 12, which is connected in the intake air line 6. There, the cold fluid absorbs heat from the intake air, cools it and is then pumped back into the reservoir 19 via a second fluid line 22. With the valves 24 and 25, the memory 19 can be decoupled from the intake air preheating system 2 as needed.

FIG. 3 shows an intake air tempering device 18 according to a second embodiment of the invention with indirect cooling of the fluid circulating in the intake air preheating system 2. In this case, a heat exchanger 23 is connected on the one hand in the circuit 13 of the intake air preheating system 2 and on the other hand between the first 20 and second fluid line 22.

For loading the accumulator 19, the valves 24, 25 in the first 20 and the second fluid line 22 are closed. A third fluid line 26 connects the first fluid line 20 to the second fluid line 22 and leads via a heat exchanger 27, through which cold air flows on the secondary side. A pump 28 ensures a continuous circulation and further cooling of the fluid in the circuit 66. The cooled fluid with eg up to -40 ⁰ C is stored in the memory 19. Depending on the design, this day container can hold up to 1000m3, for example.

Figures 4 and 5 show how the cold air is generated for the cooling of the fluid. Hot compressed air 29 from the gas turbine compressor 4 is cooled in heat exchange with water from the water-steam cycle, at the same time increasing the production of steam in the waste heat steam generator. In FIGS. 4 and 5, a heat exchanger 30 for medium-pressure feedwater 31 and a heat exchanger 32 for condensate 33 are connected in the compressor air line 34 for this purpose.

A throttle 35, as shown in Figure 4, or an expansion turbine 36, as shown in Figure 5, relax the cooled air to ambient pressure, the air temperature continues to drop. Accumulating water or ice is separated from the cooled air in a water-ice separator 37.

This cold air cools the fluid via the heat exchanger 27 known from FIGS. 2 and 3 and is subsequently fed to a chimney 41 (see FIG. 6) 65. Alternatively, the chilled air can also be used in a cooling circuit for generator cooling or in the condenser become. In another solution, the refrigeration could also be done with conventional chillers.

FIG. 6 shows a gas and steam turbine plant 38. Following the description of FIG. 1, the hot exhaust gases of the gas turbine plant 1 are supplied to the waste heat steam generator 40 through the exhaust gas line 39 and flow through them until they reach the environment through a chimney 41. On their way through the heat recovery steam generator 40, they pass their heat to a high pressure superheater 42, then a high pressure reheater 43, a high pressure evaporator 44, a high pressure preheater 45, then a medium pressure superheater 46, a medium pressure evaporator 47, a medium pressure preheater 48, then a low pressure superheater 49, a low pressure evaporator 50 and finally a condensate preheater 51.

In the high pressure superheater 42 superheated steam is supplied through a steam discharge 52 of a high-pressure stage 53 of the steam turbine 54 and there relaxed under the power of work. Work becomes analogous to what is done in the gas turbine

Work, the shaft 10 and thus the generator 11 moves to generate electrical energy. The partially relaxed in the high-pressure stage 53 hot steam is then fed to the high-pressure reheater 43, reheated there and fed via a derivative 55 and a steam supply to a medium-pressure stage 56 of the steam turbine 54 and relaxed there under the power of mechanical work. The partially relaxed steam there is fed via a supply line 57 together with the low-pressure steam from the low-pressure superheater 49 to a low-pressure stage 58 of the steam turbine 54, where it is further expanded while releasing mechanical energy.

The expanded steam is condensed in the condenser 59, and the resulting condensate is a condensate pump 60 directly to a low pressure stage 61 of the heat recovery steam generator 40 or via a feed pump 62, and provided by this with a corresponding pressure, a medium-pressure stage 63 or a High-pressure stage 64 of the heat recovery steam generator 40 is supplied, where the condensate is evaporated. After a steam discharge and overheating of the steam via the corresponding derivatives of the heat recovery steam generator 40 is fed back to the steam turbine 54 for relaxation and performing mechanical work.

To integrate the cooling in the water-steam circuit of the gas and steam turbine plant 38, as already described in Figures 4 and 5, hot compressed air 29 diverted from the gas turbine compressor 4, in heat exchange with

Medium pressure feed water 31 and condensate 33 cooled and returned at the end of the process of cooling of the fluid in the chimney 41 65.

FIG. 7 shows the alternative use of the memory 19 as

Heat storage. The fluid stored in the reservoir 19 is pumped by a pump 28 into the intake air preheating system 2. The line 26 via the air-fluid heat exchanger 27 and the bypass line 21 are closed in this case. The heating of the fluid takes place in the heat exchanger 15 with steam from the water-steam cycle 16 of the gas and steam turbine plant 38. The heated fluid is then not passed through the heat exchanger 12, but directly via the line 67 back into the memory 19th directed.

For storing out the heat, i. for warming up the intake air, the fluid is pumped from the reservoir 19 into the intake air preheating system 2 and passed through the intake air heat exchanger 12 shown in Figs.

Claims

claims

1. A Ansauglufttemperiereinrichtung (18) comprising a one hand in an intake air line (6) connected heat exchanger (12), on the other hand in a circuit (13) of an intake air preheating system (2) is connected, characterized in that a memory (19) for a fluid for heat transfer to the circuit (13) is thermally connectable.

2. The Ansauglufttemperiereinrichtung (18) according to claim 1, wherein the memory (19) is thermally connected to the circuit (13), that a first fluid line (20) branches off from the memory (19) and in the circuit (13) opens and a second fluid line (22) branches off from the circuit (13) and opens into the reservoir (19).

3. The Ansauglufttemperiereinrichtung (18) according to claim 1, wherein a heat exchanger (23) switched into the circuit (13) and connected via a first and a second fluid line (20,22) to the memory (19).

4. The Ansauglufttemperiereinrichtung (18) according to any one of the preceding claims, comprising a storage circuit (66) comprising the memory (19), a between the first (20) and the second fluid line (22) connected to the third fluid line (26), and sections of the first (20) and second (22) fluid lines from the reservoir (19) to the third fluid line (26), wherein an air-fluid heat exchanger (27) on the one hand in the storage circuit (66) and on the other hand in a from a compressor (4) branching air line (34) is connected.

5. The Ansauglufttemperiereinrichtung (18) according to claim 4, wherein at least one further heat exchanger (30,32) for

Cooling of the air in the air line (34) in the flow direction of the air on the primary side in front of the air-fluid heat exchanger (27) is connected.

6. The Ansauglufttemperiereinrichtung (18) according to claim 5, wherein a pressure reducing valve (35) between the at least one further heat exchanger (30,32) and the air-fluid heat exchanger (27) in the air line (34) is connected.

7. The Ansauglufttemperiereinrichtung (18) according to claim 5, wherein an air expansion turbine (36) between the other heat exchanger (30,32) and the air-fluid

Heat exchanger (27) is connected in the air line (34).

8. The Ansauglufttemperiereinrichtung (18) according to any one of the preceding claims, wherein the fluid for heat transfer contains water and an antifreeze.

9. gas turbine plant (1) with a Ansauglufttemperiereinrichtung (18) according to any one of the preceding claims.

10. Gas and steam turbine plant (38) with a Ansaugluft- tempering device (18) according to one of claims 1 to

11. A method of operating a Ansauglufttemperiereinrichtung (18) with an intake air preheating system (2), characterized in that a fluid for heat transfer from a memory (19) and stored the intake air preheating system (2) supplied to change the temperature of an intake air becomes.

12. The method of claim 11, wherein compressed compressor air is cooled in heat exchange with water.

13. The method of claim 12, wherein a throttle (35) relaxes the cooled compressor air.

14. The method of claim 12, wherein an expansion turbine (36) relaxes the compressor air.

15. The method of claim 13, wherein relaxed compressor air cools the fluid in heat exchange.