DE102011102599A1 - Method for operating a small gas turbine arrangement, and small gas turbine arrangement itself - Google Patents

Abstract

The invention relates to methods for operating a small gas turbine arrangement, and small gas turbine arrangement itself, with at least one compressor / stage and at least one turbine or turbine stage, in which the compressor and turbine / turbine stages act on a generator axis for power generation. In order to achieve a significant increase in efficiency, it is proposed according to the invention that a combustion chamber is arranged in front of each turbine or turbine stage in the case of a number of N turbines or turbine stages, and that the gas outlet of each turbine or turbine stage first enters the combustion chamber of the next turbine or turbine stage is initiated, and that the gas outlet of the last turbine or turbine stage in turn leads via recuperation thermal energy back into the gas stream before entering the first combustion chamber of the first turbine stage.

Description

The invention relates to a method for operating a small gas turbine arrangement, as well as a small gas turbine itself, according to the preamble of patent claims 1 and 11.

Micro or small gas turbines are becoming increasingly important in connection with the use of renewable energy sources or renewable raw materials. Meanwhile, techniques are known in which high process temperatures are achieved with the help of dust firing of dry biomass. With regard to the overall concept, small gas turbines are therefore important for the generation of electricity from renewable raw materials. It is also known that gas turbines currently achieve a maximum efficiency of less than 40% with the cycle processes carried out.

The invention is therefore based on the object to further develop a method of the generic type to the effect that significantly higher efficiencies, and in particular a particularly applicable to the use of renewable raw materials Applicable technique arises.

The stated object is achieved in a method of the generic type by the characterizing features of claim 1.

Further advantageous embodiments of the method are specified in the dependent claims 2 to 8.

With regard to a small gas turbine itself, the stated object is achieved by the characterizing features of claim 11.

Further relevant embodiments are specified in the remaining dependent claims.

This is followed in claims 9 and 10, a use according to the invention.

Core of the inventive method is that in a number of N turbines, before each turbine or turbine stage, a combustion chamber is arranged, and the gas outlet of each turbine or turbine stage is first introduced into the combustion chamber of the next turbine or turbine stage, and that the gas outlet the last turbine or turbine stage in turn via a recuperation thermal energy back into the gas stream before entering the first combustion chamber of the first turbine stage leads.

The resulting benefits is that this leads to a significant increase in efficiency.

In addition, such small gas turbine arrangements can be built extremely compact. Furthermore, a high speed is created, with means that will be described in more detail below.

In a further advantageous embodiment, it is stated that in the mechanical rotational engagement of the turbines or turbine stages, a compressor arrangement with M stages is provided, in which the compressor stages (1 to M) are connected in series (pressure medium-locking), and that between each two successive compressor stages, d. H. behind each compressor stage, a liquid evaporator medium is injected, such that also behind the last compressor is also a final injection. This concept results in the already mentioned efficiency increases in the process.

One of the essential aspects of the invention is that the small gas turbine arrangement is configured with a plurality of compressor stages and a plurality of turbine stages, in the manner of a turbine circuit process.

• – Als Getriebeaufbau mit einem zentralen Sonnen-Zahnrad mit dem der Generator verbunden ist, und auf den Sternrädern angeordnete Verdichter- und Turbinen-Stufen mechanisch gekoppelt sind.
• – Jeweils eine bzw. max. zwei Verdichter- oder Turbinen-Stufen auf den beiden Seiten einer Sternradwelle.
• – Die Möglichkeit, dass unterschiedliche Geschwindigkeiten von Verdichter-Stufen und Turbinen-Stufen gegeben sind, ergibt sich aufgrund der Anordnung bzw. Verwendung mehrerer Wellen.

In summary, the following aspects are revealed in detail in this concept.

• - As a gear assembly with a central sun gear to which the generator is connected, and arranged on the star wheels compressor and turbine stages are mechanically coupled.
• - One or max. two compressor or turbine stages on both sides of a starwheel shaft.
• - The possibility that different speeds of compressor stages and turbine stages are given, results from the arrangement or use of multiple waves.

• – Freie Auswahl als Axial- oder Radial-Ausführung der Verdichter oder der Turbinen-Stufen.
• – Eine fest wählbare Drehzahl für Generator (Sonnenzahnrad) ist möglich, vorgegeben durch die jeweilig vorhandene, oder gewünschte Netzfrequenz (üblich 50 oder 60 Hz).
• – Leistungsregelung der Klein-Gasturbine bei konstanter Drehzahl mittels Verstellung der Leitschaufeln in der ersten Verdichterstufe.
• – Jeweils eine Kühlung nach jeder Verdichterstufe.
• – Kühlung durch Verdampfung von Verdampfermedium, bspw. Wasser, vorzugsweise aber nicht ausschließlich bis zum Sättigungspunkt.
• – Kühlungsenergie bleibt dem bzw. im System erhalten, und stellt auch diesbezüglich den Kreisprozess dar.
• – Nutzung der Abwärme als Wärmeauskoppelung: Heiz-Kraft-Gasturbine (HKGT), oder weitere Nutzung der Abwärme mittels ORC Anlage.
• – Für Insel- oder Netzparalell-Betrieb geeignet.
• – Mehrstufiger Verdichter.
• – Mehrstufige Turbine mit Zwischenverbrennung.
• – Verdichterkühlung nach der Verdichtung.
• – Rekuperation und Verdichterkühlung zusammen eingesetzt.

A single-wave arrangement is nevertheless not excluded.

• - Free choice as axial or radial version of the compressors or turbine stages.
• - A fixed selectable speed for generator (sun gear) is possible, given by the respective existing, or desired network frequency (usually 50 or 60 Hz).
• - Constant speed control of the small gas turbine by means of adjusting the guide vanes in the first compressor stage.
• - One cooling after each compressor stage.
• - Cooling by evaporation of evaporator medium, for example. Water, but preferably not exclusively to the saturation point.
• - Cooling energy is retained to or in the system, and also represents in this regard the cycle.
• - Utilization of the waste heat as heat decoupling: heating / power gas turbine (HKGT), or further use of the waste heat by means of ORC plant.
• - Suitable for island or grid parallel operation.
• - Multi-stage compressor.
• - Multi-stage turbine with intermediate combustion.
• - Compressor cooling after compression.
• - Used recuperation and compressor cooling together.

Although the recooling in series circuits of compressors per se state of the art. However, the difference according to the invention in this case consists in the fact that in the evaporator media injection according to the invention or designed according to the invention, the energy absorbed by the cooling system (i.e., energy removal by reducing the air temperature) is not dissipated beyond the system boundary but remains in the system (in the manner of a cyclic process).

With the evaporator medium water, the system is easy and effective to operate. Especially at the resulting process temperatures of several hundred degrees Celsius.

Nevertheless, other evaporation media than water are possible.

Accordingly, it is further configured that also liquid fuel is used as the evaporator medium, and thus injected at those injection sites at which the evaporator medium is injected.

The liquid fuel initially serves as evaporator media.

From the use of flux fuels at the same time as the evaporator medium and fuel there are a number of advantages. Due to the multi-stage injection of the fuel, initially as the evaporator medium, there is a subsequent optimal air mixing of the fuel, and then ensures in the combustion chamber for optimal subsequent combustion. It is important in the case of the use of evaporable liquid fuels, first as the evaporator medium, that the process is controlled so that there is no ignition of the evaporated fuel outside of the combustion chambers.

Since the often very volatile liquid fuels have a high evaporation enthalpy, their use is also highly suitable as the evaporator medium.

In the low-temperature range, for example in the area of cooling, it is also possible to use ORC medium (Organic Rankine Cycle) for the postcurrent treatment of this low calorific waste heat. However, this takes place in a separate cyclic process separated from the above-mentioned cyclic process.

Furthermore, it is advantageously designed so that even before entering the turbines or in the turbine stages evaporator medium, preferably water is temporarily injected for the purpose of turbine cleaning.

With regard to the fuel for such an arrangement, in principle for this process, any energy carriers in liquid and / or gaseous and / or powdered form can be injected into the combustion chambers.

Furthermore, it is advantageously configured that a power control of the small gas turbine or the small gas turbine arrangement takes place by an adjustment of the angle of attack of the guide vanes in at least the first compressor stage.

Furthermore, it is advantageously configured that the turbines and the compressors mechanically engage with a shaft coupled to a generator / motor arrangement, and that in a starting mode the generator is operated in the drive or motor mode and subsequently in the generator mode. So it requires only one relevant aggregate with the said dual function. The execution of this dual function lies in the unit-external electrical switching between motor and generator operation.

Furthermore, a significant advantageous use of biomass dust-finely ground, with ash melting points above 1000 ° C, for injection into the combustion chambers by the method according to one of claims 1 to 9 given. The reason for this is not trivial. At temperatures in this range, there is a high degree of efficiency per se. However, in order to reach these temperatures, it is necessary to also have available a biomass which, for example, has a high lignin content. This is far from being achieved by every renewable resource. Slowly growing woods such as poplar and willow but rather achieve this than short-rotation plants.

A special exception here is the biomass IGNISCUM (CPVO 2007/0149). Although this is also a short rotation plant with at least one harvest per year, its lignin content is surprisingly high and above all, the ash melting point is well above 1,000 ° C.

As a result, the combustion is effective, without sooting etc., and protects the turbines by avoiding or significantly reducing deposits.

For this reason, said biomass is so advantageous in connection with the method and the device according to the invention.

Furthermore, this biomass Igniscum has the advantage that it is both solid or dust-fine fuel, as biogas can be obtained. The mixed fuel supply of simultaneously gas and dust from the same energy plant achieves extremely high combustion temperatures with almost completely residue-free combustion.

With regard to a small gas turbine arrangement itself, the core of the invention consists in that a combustion chamber is arranged in front of each turbine or turbine stage in a number of N turbines or turbine stages, and the gas outlet of each turbine or turbine stage first into the combustion chamber of the next turbine or turbine Turbine stage is initiated, and that the gas outlet of the last turbine or turbine stage in turn leads via a recuperation thermal energy back into the gas stream before entering the first combustion chamber of the first turbine stage.

Furthermore, a combination of recuperation, unconventional compressor cooling and multi-stage combustion, as the essence of the invention. This causes the following:
The recuperation ensures that a significantly higher efficiency is achieved with a lower compression ratio.

The cooled outlet air from the last compressor stage ensures that recuperation becomes significantly more effective.

Multi-stage combustion increases the average working temperature of the heat supply, thus increasing thermal efficiency. Multi-stage steam turbines with reheat are known, but small gas turbines with intermediate combustion are not common. Due to the combination of recooling and recuperation not previously used with small gas turbines and a multi-stage (at least two-stage) turbine with intermediate combustion, a mechanical efficiency of equal to or greater than 50% can be achieved.

Another potential of the increase in efficiency lies in the still possible turbine blade cooling.

Type of cooling:

Cooling at the outlet behind each compressor stage: A maximum of so much evaporator medium is introduced into the air stream that the saturation point of the air is reached according to their state variables behind the compressor stage.

The evaporator medium, for example. Water is finely injected so that it evaporates, in each case at a defined point in the process. This requires small droplets. The small size of the droplets favors the ratio of drop surface to drop volume. This means that the drop surface becomes large in relation to the drop volume.

Multi-stage compressors are known per se. With each compressor stage, the air is supplied with additional energy, or the pressure of the compression process is increased. When cooling multistage compressors, the compression is kept almost isothermal and thus requires less compressor work.

The peculiarity, however, lies in the fact that with small gas turbines the cooling is used on the one hand behind the compressor stage and on the other so targeted that after the last compressor stage recuperation is extremely effective and still the energy that is absorbed by the evaporative cooling, the system is not leaves.

Also, multi-stage transmission compressors are generally known per se. In contrast, the invention provides an arrangement for small gas turbines in which the simultaneous placement of the turbine stages is brought together on a common transmission with the multi-stage compression. On the one hand, this results in a very considerable compactability of the arrangement, but on the other hand also leads to the total heat balance or the overall heat conduction of the process being considerably optimized.

In a further advantageous embodiment, it is therefore stated that in the connecting line between the (n-1) -th and the n-th compressor stage, as well as directly after the nth compressor stage, the injection of the evaporator medium takes place through an injection opening arranged there, such in that the evaporation takes place shortly before reaching the subsequent compressor stage, unless it is the injection opening behind the last compressor stage, so that at the same time a drop erosion of the compressor is avoided.

Further, it is advantageously designed that the central shaft of the generator is provided with a sun gear or connected, and that the individual shafts of both the turbine or turbine stages, and the compressor or Compressor stages are provided with gear elements and engage the central sun gear element of the generator shaft. This causes the very significant, already described above compactness of the arrangement with all the advantages already mentioned.

It is advantageous here that a combined generator / motor arrangement is arranged on the central shaft. By appropriate simple electrical wiring from the outside, the generator assembly can also be temporarily switched to engine function to start the turbine and compressor assembly first. Later, d. H. after starting it is switched back to generator mode.

In order to design this accordingly, it is further proposed that the turbines or turbine stages, as well as the compressors or compressor stages themselves, are arranged planet-like around the central generator arrangement, thus forming a compact structural unit.

In a further advantageous embodiment, it is provided that all the transmission elements are arranged in an existing housing parts but ultimately in a coherent in the assembled state housing. The case may be jagged, but still connected. So also an effective heat management is possible. Mechanically, however, this compactness also has the advantage that the transmission elements are so compact that a friction-reduced gear engagement is possible.

As an alternative embodiment, the realization of the inventive concept but also in a serial compressor and turbine arrangement is possible. This design relates to a single-shaft configuration of the entire arrangement.

An embodiment of the invention is illustrated in the drawing and explained in more detail below.

It shows:

1 : Schematic representation of the entire process.

2 : Design of a compact arrangement with sun gear.

1 shows a schematic representation of the process with a multi-stage compression (here m = 4). In the first compressor stage 1 outside air is sucked in, and before it enters the second compressor stage 2 is, is between the first and second compressor stage, the first injection site 5 , which can also be designed as a conduit extension, that forms an injection space. Between the compressor stage 2 and 3 is another injection site 6 , and between the third and the fourth compressor stage is the further injection site 7 placed. Also at the output of the fourth and thus last compressor stage 4 is another injection site 8th placed. From there it goes then pressure-locked into the first combustion chamber 13 in which gaseous and / or liquid and / or pulverulent solid fuel, such as. Igniscum powder is sprayed for combustion. From there it goes into the first turbine 10 or the first turbine stage 10 , The output of the first turbine stage 10 then flows into the second combustion chamber 14 , in which also Igniscum powdery ground is sprayed. In both combustion chambers 13 and 14 can also be any other fuel, gaseous, liquid, or sprayed as pulverized solid fuel.

As stated above, is between the output of the last compressor stage 4 after the cooling injection site 8th a recuperator 12 arranged, wherein the resulting heat at the second turbine stage to the point before entering the first combustion chamber 13 , so recuperating in the process. The residual heat generated there is still remanufactured by a downstream ORC cycle. For this purpose, this heat through a heat exchanger 32 passed, which transfers the residual heat of the primary process in a low-temperature working fluid. From there it goes over a turbine 31 in the ORC process, which is coupled to a second generator. The output of the turbine 31 is about a recuperation 33 in the ORC process and then a capacitor 35 subsequently, the ORC medium in the ORC cycle is pumped 34 guided. This is therefore an arrangement of N = 2 turbines, and also N = 2 combustion chambers.

All compressors and turbines arranged in the primary process are in mechanical operative engagement with each other. This can be realized by a common shaft, or by a gear coupling. An example of a gear coupling is in 2 executed. 2 shows a very much advantageous design, through the use of a central arrangement of the generator 20 and arranged on the shaft sun gear has all other components such as turbines and compressors in mechanical engagement. The compressors 1 to 4 are located below, and the generator 20 is centrally located around the axis not shown here (central shaft).

The compressor 1 has the setting means for the compressor vanes. The turbines 10 and 11 are above the generator 20 placed and there is the first turbine 10 arranged in front and the second turbine behind. Between the individual compressor stages, the water or evaporator media injection sites are placed. The item numbers 13 and 14 show the also structural integration of the two combustion chambers.

The invention thus described is a specific gas turbine cycle process that uses continuous water injection to recirculate the compression process, uses the energy of the combustion gas to a very high degree in the context of recuperative heat transfer, and utilizes multiple combustion to further enhance efficiency.

LIST OF REFERENCE NUMBERS

1, 2, 3, 4

compressor

5, 6, 7, 8

Injection sites / injecting rooms

10

first turbine

11

second turbine

12

Recuperator in the main process

13

first combustion chamber

14

second combustion chamber

20

Generator / motor in the main process

30

Generator in the ORC process

31

Turbine in the ORC process

32

heat exchangers

33

recuperator

34

pump

35

capacitor

Claims (17)

Method for operating a small gas turbine arrangement having at least one compressor / stage and at least one turbine or turbine stage, in which compressor and turbine / turbine stages act on a generator axis for generating electricity, characterized in that with a number N turbines, before each turbine ( 10 . 11 ) or turbine stage a combustion chamber ( 13 . 14 is arranged, and the gas outlet of each turbine or turbine stage is first introduced into the combustion chamber of the next turbine or turbine stage, and that the gas outlet of the last turbine or turbine stage in turn via a recuperation thermal energy back into the gas stream before entering the first combustion chamber of the first turbine stage leads. A method according to claim 1, characterized in that in mechanical rotary engagement of the turbine or turbine stages, a compressor arrangement with M stages is provided, in which the compressor stages (1 to M) (pressure medium-locking) are connected in series, and that between each two successive compressor stages , d. H. behind each compressor stage, a liquid evaporator medium is injected, such that also behind the last compressor is also a final injection. A method according to claim 2, characterized in that the evaporator medium is water. A method according to claim 2, characterized in that the evaporator medium is liquid fuel. Method according to one of claims 1 to 4, characterized in that even before entering the turbine or turbine stages evaporator medium, preferably water is temporarily injected for the purpose of turbine cleaning. Method according to one of the preceding claims, characterized in that as energy carriers liquid and / or gaseous and / or dust-like energy carriers are injected into the combustion chambers. Method according to one of the preceding claims, characterized in that a power control of the small gas turbine or the small gas turbine arrangement is effected by an adjustment of the angle of attack of the guide vanes in at least the first compressor stage. Method according to one of the preceding claims, characterized in that the turbines and the compressors mechanically engage a coupled to a generator / motor assembly shaft, and that in a starting mode, the generator in the drive or motor mode and subsequently in the operating mode of the generator in the generator mode is operated. Use of biomass pulverized dusty, with ash melting points above 1000 ° C, for injection into the combustion chambers by the method according to one of claims 1 to 8. Use according to claim 9, characterized in that the biomass is IGNISCUM (CPVO 2007/0149), or wood, in particular poplar and / or willow. A small turbine arrangement having at least one compressor / stage and at least one turbine or turbine stage, in which compressors and turbine / turbine stages mechanically act on a common generator axle / generator shaft for power generation, or are coupled with this gearbox, characterized in that with a number N turbines ( 10 . 11 ) or turbine stages, before each turbine or turbine stage, a combustion chamber ( 13 . 14 ) is arranged, and the gas outlet of each turbine or turbine stage is first introduced into the combustion chamber of the next turbine or turbine stage, and that the Gas outlet of the last turbine or turbine stage in turn via a recuperation thermal energy back into the gas stream before entering the first combustion chamber of the first turbine stage leads. Small gas turbine arrangement according to claim 11, characterized in that in the connecting line between the (n-1) -th and the n-th compressor stage, as well as after the nth compressor stage, the injection of the evaporator medium by a respective injection port arranged there ( 5 . 6 . 7 . 8th ) takes place, such that the evaporation already takes place shortly before reaching the compressor stage, so that at the same time a drop erosion of the compressor is avoided. A small gas turbine arrangement having at least one compressor / stage and at least one turbine or turbine stage, in which compressors and turbine / turbine stages mechanically act on a common generator axis / generator shaft for power generation, or are coupled with this transmission technology, according to claim 11, characterized in that the central Wave of the generator / motor is provided with a sun gear or connected, and that individual shafts of both the turbines, or turbine stages, and the compressor or compressor stages are provided with gear elements and engage the central sun gear element of the generator shaft. Small gas turbine arrangement according to one of the preceding claims 11 to 13, characterized in that a combined generator / motor arrangement is arranged on the central shaft. Small gas turbine arrangement according to claim 12, characterized in that the turbines or turbine stages, and the compressor or compressor stages themselves are arranged like a planet around the central generator assembly around, and thus form a compact unit. Small gas turbine arrangement according to one of claims 11 to 15, characterized in that all the transmission elements are arranged in a housing parts consisting of but ultimately in a connected state in the assembled housing. Small gas turbine arrangement according to one of claims 11 to 16, characterized in that the recuperator ( 12 ) of the primary process at the exit of the turbine ( 11 ) is thermally associated with an ORC (Organic Rankine Cycle) cycle for the postcurrent of low temperature waste heat.

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