EP4008958A1 - Gas turbine combustion chamber system and method for operating same - Google Patents

Abstract

The invention relates to a gas turbine combustion chamber system (1), in particular a micro gas turbine combustion chamber system, having a combustion chamber (30) which has a longitudinally extending flame tube (34) surrounding a flame zone, which is provided with a burner (31) on its inlet side and is coupled or can be coupled to a turbine arrangement on its outlet side facing away from it and is provided with mixed air openings (320) in an outlet section, - with a pressure housing (2) surrounding the combustion chamber (30), between its inside and the outside of the flame tube (34) for supplying an air mass flow, an inflow channel (330) leading from its output side to the input side is formed, via which a mixed air portion via the mixed air openings (320) into the interior of the flame tube (34) and a burner air portion to the burner (31) for combustion with the fuel that has flowed in is guided, and with a control device via which the burner (31 ) supplied proportion of burner air can be regulated by varying the proportion of mixed air depending on the load point of the turbine arrangement by adjusting the clear flow width of the mixed air openings (320). Reliable, low-emission combustion over the entire load range is achieved in that the control device is based on a pressure difference (Δp ) between the inflow duct (330) for the air and the area surrounding the combustion chamber system (1) has an responsive adjusting device (4), by means of which the clear flow width of the mixed air openings (320) can be reduced as a function of the load point, in particular continuously, with an increasing load point and with a decreasing Load point can be increased

Description

The invention relates to a gas turbine combustion chamber system, in particular a micro gas turbine combustion chamber system, with a combustion chamber which has a flame tube which extends longitudinally and surrounds a flame zone, which is provided with a burner on its input side and is coupled or can be coupled to a turbine arrangement on its output side remote from this and is provided with mixed air openings in an outlet section, with a pressure housing surrounding the combustion chamber, between the inside of which and the outside of the flame tube for supplying an air mass flow is formed an inflow channel leading from its outlet side to the inlet side, via which a proportion of mixed air via the mixed air openings into the interior of the Flame tube and a burner air portion is led to the burner for combustion with inflowing fuel, and with a control device via which the burner air portion supplied to the burner can be regulated by the mixed air portion l is varied depending on the load point of the turbine arrangement by adjusting the clear flow width of the mixed air openings. The invention also relates to a method for operating a gas turbine combustion chamber system, in particular a micro gas turbine combustion chamber system, according to one of the preceding claims, in which an air mass flow is supplied via an inflow channel between the inside of a surrounding pressure housing and the outside of a flame tube from its outlet side and by means of mixed air openings arranged in an outlet section of the flame tube into a mixed air portion , which is directed into the interior of the flame tube behind a flame zone, and a proportion of burner air is divided, which is fed to a burner arranged on the inlet side of the flame tube for combustion with fuel, the fuel/air ratio being varied by varying the clear flow width of the mixed air openings by means of a Control device is regulated.

the GB 1 601 218 A shows a gas turbine combustion chamber system with mixed air openings on a flame tube, which are arranged in an inflow duct and whose flow width can be controlled mechanically by means of a valve via a pressure difference between the inflow duct and outside air. For this purpose, the pressure in the supply channel acts via an opening on a piston arranged in a cylinder chamber and the external pressure via an opening in a valve arrangement. A primary air intake is controlled by another valve. This combustion chamber system thus contains a number of coordinated, interacting valves with a relatively large number of individual system components, which necessitate the associated expense in terms of construction and maintenance and can cause malfunctions.

Also the print DE 19 45 921 A shows a gas turbine combustion chamber system in which mixed air openings on a flame tube in an inflow duct for the air are controlled in terms of their flow width as a function of a pressure difference between the pressure in the inflow duct and the external environment. In this case, a jacket-shaped panel can be displaced by an actuator by means of a spring-loaded piston.

A gas turbine combustor system and a method of operating a gas turbine combustor system are also in US Pat DE 41 20 831 A1 specified. In this known gas turbine combustor system and method for its operation in different operating conditions, such. B. load point of a turbine at partial load to full load, hot gases are generated from the combustion of a compressed air flow. In order to prevent an excess of air in the flame zone, means are activated which respond to a pressure difference between the combustion chamber itself and the compressed air. The funds consist z. B. in spring components with a check valve and cause a bypass flow of part of the compressed air into a mixing zone on the outlet side of the flame zone or combustion zone, for which purpose the resilient element of the means, depending on the pressure difference, covers a distance which opens the relevant valve for a bypass flow of part of the compressed air into the mixing zone. The means of the control device, which are made up of several individual parts and are individually assigned to the mixed air openings, for controlling the proportion of mixed air through the mixed air nozzles and thus also the proportion of the burner air supplied to the burner, results in a relatively high design effort, especially in micro gas turbine combustion chamber systems, which also means that the fuel can be adjusted as reliably as possible -/air ratio in the burner or the combustion air ratio (air ratio A) is difficult for consistently low-emission and efficient combustion. This structure also involves a relatively high commissioning effort and maintenance effort and also an increased risk of failure.

A gas turbine combustor system and method of operating same is also disclosed in US Pat DE 43 04 201 A1 specified. In this case, a flame tube is spaced apart, forming an annular air duct, concentrically surrounded by an outer jacket and in turn encloses a combustion chamber. Compressed air is supplied via the air duct to a burner that protrudes through the outer shell and the flame tube into the combustion chamber, and mixed air nozzles are arranged on the circumference of the flame tube, which connect the air duct with the combustion chamber in order to introduce secondary air (mixed air) through the mixed air nozzles into the hot gas stream in the flame tube. The mixed air nozzles can be individually regulated to vary the proportion of mixed air, since a tried and tested solution with an adjusting ring common to all mixed air openings was considered disadvantageous there. However, the disadvantages mentioned above also arise with the individual control components of the individual mixed air nozzles.

the AT 6 537 E shows a displacement of an inner liner in a combustor system according to the balance of the pneumatic force of a fuel pressure on the left side of a floor and a force acting on the right side of the floor, turbine side, by a pressure built up there. A bellows-like structure is also shown.

Various other proposed solutions for controlling the burner air supplied to a burner in a gas turbine combustion chamber system are shown in FIG GB 1257610A , the EP 2778531 A1 , the FR2133832A1 , the GB 2277582A , the US 3952501A and the DE 19545311 B4 , where various actuators, mostly addressed by active control, are arranged in the inflow channel of the air mass flow and adjustment paths, forces, temperatures or pressures are manipulated. With such actively controlled devices, it is true that the system can be directly adapted to the specific circumstances of each individual gas turbine. A disadvantage is, however, that this is associated with an increased commissioning effort and the various components and actuators result in a relatively high maintenance effort and an increased risk of failure, which creates disadvantages in the goal of low-emission, reliable combustion, especially in connection with micro gas turbine combustion chamber systems can be achieved over the entire load range.

In micro gas turbine combustor systems, the air mass flow through the turbo components varies greatly with the load point of the connected turbine arrangement over its load range or the required electrical power. Likewise, there is a strongly varying demand for fuel output and thus for fuel mass flow between minimum and full load. The respective ratio between air mass flow and fuel mass flow over the load range is not constant, but is shifted in the direction of larger air mass flows at part load. In the prior art, combustion chambers with fixed predetermined geometries are used in micro gas turbines. Therefore, over the entire load range, there is an approximately constant distribution between the air that is routed through the burner and the mixed air that is mixed in after the combustion zone in the flame tube.

Due to this constant air distribution, there is a shift in the ratio between air and fuel in the reaction space of the combustion chamber, which leads to a significant change in the combustion air ratio A, as in figure 5 shown in which the air ratio λ (abscissa 5) emissions e (ordinate 6) of CO (reference number 60) and NO _x (reference number 61) are shown at full load and part load. This means that the conditions in the combustion chamber are significantly leaner at part load than at full load. This means that with burners that are optimized for NO _x at full load, the CO emissions leave the equilibrium path at part load and are determined by non-equilibrium effects due to insufficient residence times at the high air ratios λ. As a result, the CO emissions sometimes increase sharply at part load.

The same applies to the unburned hydrocarbons (UHCs). This effect can be partially compensated by fuel staging by enriching a pilot stage at part load. However, this is bought at the cost of an increase in NO _x emissions at part load. Furthermore, the piloting can only compensate for the influence of the air ratio shift to a limited extent, so that also for this If there is always a trade-off between exhaust emissions at full load and at part load.

When fuel is staged, the fuel mass flow to be introduced is distributed unequally to different burner stages, so that locally richer and therefore hotter areas of premixed combustion result. As a result, combustion is stabilized and at the same time CO and UHC emissions are reduced at load points, which are globally associated with a very lean state. This is typically the case at part load. However, due to the locally higher combustion temperatures, the NO _x emissions increase at the same time. Furthermore, a reduction in CO emissions under globally extremely lean conditions, as sometimes occur in micro gas turbines close to the minimum load point, is only possible to a very limited extent by fuel staging, so that considerable CO and UHC emissions are still emitted at these load points.

In addition, obstructing the flow path to the burner leads to an increased pressure loss in the gas turbine combustion chamber system, in particular micro gas turbine combustion chamber system, as a result of which the efficiency of the gas turbine, in particular micro gas turbine, is negatively influenced by built-in components of the control device, such as throttles and valve components in the air path.

Based on these disadvantages of known gas turbine combustion chamber systems with air control devices and taking into account the above preliminary considerations and findings, the invention is based on the object of developing a gas turbine combustion chamber system, in particular a micro gas turbine combustion chamber system, in such a way that low-emission, reliable combustion is achieved over the entire load range of an associated turbine arrangement, and a corresponding one procedures to provide.

This object is achieved in a gas turbine combustor system with the features of claim 1 and in a method for operating such with the features of claim 14.

In the gas turbine combustion chamber system (hereinafter also referred to as combustion chamber system for short), it is provided according to the invention that the control device has an adjusting device that responds to a pressure difference (Δp) between the inflow channel of the air and the environment of the combustion chamber system (usually atmospheric pressure), by means of which the clear flow width (Flow cross-section) of the mixed air openings depending on the load point, in particular continuously, can be reduced with an increasing load point and increased with a decreasing load point.

In the method for operating a gas turbine combustion chamber system, it is provided in connection with the features of the preamble that the clear flow width of the mixed air openings is regulated as a function of the pressure difference (Δp) between the inflow duct and the external environment of the combustion chamber system by the clear flow width with an increase in the Load point of a coupled turbine assembly is reduced and increased with a reduction in load point.

With these measures, the pressure difference of the air in the inflow duct or an inflow pipe arranged there and the area around the combustion chamber system around the pressure housing is advantageously used to control the burner air flow and thus the fuel/air ratio present during combustion, whereby the air ratio at different load points exceeds the load range of a coupled turbine can be maintained in order to achieve optimum exhaust gas values. An optimized control is also favored by the fact that there are moderate temperatures at the installation point in the area of the actuating device and the detection of the pressure difference. The pressure drop between the air of the feed channel and of the environment correlates very well over the load range of the gas turbine with the mass flow behavior required for combustion.

If it is provided that the actuating device is constructed mechanically, and in particular passively working, with the pressure difference being used directly or indirectly as a drive source, the construction can be implemented with little effort with few components with high reliability and inexpensively. With direct use of the pressure difference as a drive source, only one pressure-utilizing unit is required, with the mechanism being separated from extremely hot components of the flame tube, which contributes to high reliability. In addition, due to the passively constructed control device, in particular for the passively controlled portion of the mixed air flow, industrially available components can advantageously be used and there is a low risk of failure as a result of low complexity and low maintenance costs. The flow channel can also be streamlined and designed as unobstructed as possible in order to keep the pressure loss over the flow path of the air mass flow with the burner air proportion small, which has a positive effect on the efficiency of the micro gas turbine combustion chamber in particular.

To achieve these advantages, there are alternative design variants that, when using the pressure difference (Δp) as an indirect drive source, there is an actuating unit with a pressure sensor, a converter unit and at least one actuator driven by this, by means of which the clear flow width of the mixed air openings can be varied via a closing unit , and that when using the pressure difference (Δp) as a direct drive source, the at least one actuator itself is designed as a pressure sensor, by means of which the clear flow width of the mixed air openings can be varied via the closing unit. With the indirect use of the pressure difference as a drive source, the pressure difference can be supplied indirectly via the converter unit to control another mechanical or other physical energy source to the at least one actuator to change the clear throughflow width of the mixed air openings via the closing unit, with the pressure difference between the inflow channel and the environment being used. If the pressure difference is used as a direct drive source for the actuator, a particularly simple structure results.

One configuration that is advantageous for the design and function is that the adjusting device has a bellows, in particular made of metal, as at least one adjusting element, which is firmly connected to the pressure housing with its one end area and with its other end area spaced apart in the longitudinal direction is connected at a connecting section via at least one intermediate member to the closing unit comprising at least one closing element and that the interior of the bellows is connected to the air inflow channel via at least one pressure equalization channel. Such a bellows, in particular made of metal, is commercially available in various designs, with its deflection for adjusting the closing unit being caused on the one hand by the pressure change depending on the load point and on the other hand, counteracting the pressure, by the elastic restoring force inherent in it. The required effective force parameters can be well, z. B. by simulation and / or real tests, to the respective combustion chamber system, with further parameters to be taken into account, such as adjustment, size and shape of the mixed air openings can be determined in a suitable manner.

A further advantageous embodiment for a simple structure and reliable function is that the closing unit is designed as a screen which can be moved in a translatory manner by means of the actuator in the longitudinal direction of the flame tube, more or less closing the mixed air openings for varying the clear flow width or the flow cross section / or is rotationally adjustable in the circumferential direction. About the z. B. cuff-like diaphragm, the mixed air openings can be easily varied by a simple adjustment mechanism depending on the pressure difference. The material of the closing unit and their physical and mechanical properties can be used to achieve good functionality, e.g. B. in terms of good sliding properties at different temperatures of the flame tube.

The fact that the connecting section, the intermediate member and the closing unit are rigidly connected to one another also contributes to an advantageous construction.

Another embodiment of the combustion chamber system that is advantageous in terms of structure and function is that the pressure housing has a front wall section on its front side adjacent to the inlet side of the flame tube, on the outside of which, facing the area surrounding the combustion chamber system, several actuators are attached, and that several along the outside of the Flame tube, in particular through the inflow duct, intermediate members are designed as retaining struts or retaining rods, which are connected to the closing unit at their rear end region facing the outlet section of the flame tube and are connected to the actuators assigned to them via the connecting section at their front end region spaced from it. The front wall portion of the pressure housing is z. B. formed by a burner flange of the built-in burner.

In a further structural design, it is advantageously provided that the closing unit designed as a screen is designed as a ring screen, which runs around the flame tube in the area of the mixed air openings and extends axially over the flame tube with a constant inner cross-section adapted to the outer cross-section of the flame tube so that the clear The flow width of the mixed air openings can be varied at least to a large extent via the maximum change in the pressure difference (Δp) from completely open to partially (or not completely) closed for functional reasons, with the flame tube having a constant external cross section at least in the area of the mixed air openings and the displacement path of the ring diaphragm over an axial extension section owns. With these measures an advantageous tuning of the function to the control or regulation of the proportion of burner air over the entire load range of the turbine to achieve optimum exhaust gas values can be advantageously implemented.

A further contribution to reliable functionality is that the outer surface of the flame tube has a circular cylinder shape at least over the axial extension section in the area of the mixed air openings and the displacement path and the inner cross section of the ring diaphragm over its axial extension, which means that a simple structure and good adjustability are achieved.

It is also provided that the flame tube has several, preferably equidistant, spaced mixed air openings in the circumferential direction, for example arranged in the same plane or in several planes perpendicular to the axis of the flame tube, and that the annular baffle has several baffle openings located in the same or in several planes perpendicular to the axis of the flame tube, which spaced in the circumferential direction according to the mixed air openings and for the complete or at least extensive opening of the mixed air openings with these at a minimum pressure difference (Δp) can be brought largely or completely into alignment and for the complete or at least extensive closing of the mixed air openings at a maximum pressure difference (Δp) can be brought as far as possible or completely out of alignment are, more good tuning options are achieved in terms of precise control of the air mass flow and low-emission combustion, with z. B. the geometric shape of the mixed air openings and the baffle openings can be selected depending on the requirements for combustion at different load points of the turbine, such as size, shape and the resulting change in the clear flow width for the mixed air portion at the pressure differences that are present depending on the load point.

A further advantageous embodiment for a stable construction and a reliable function is that the support rods in their the burner to the front projecting section are guided through introduced into the front wall section of the pressure housing bores in the interior of their associated bellows and attached to these via the respective connection section. The bores can advantageously also serve as connection openings for a pressure equalization connection. Additional pressure compensation bores between the inside of the bellows and the combustion chamber are also conceivable.

A stable structure, which also promotes reliable function, is that the support rods are connected to a common, circumferential stabilizing ring, which forms a stop against the inside of the front wall section of the pressure housing when the diaphragm is adjusted in the direction of the minimum flow width or when the mixed air openings are closed .

The adjustment of the screen is also favored by the fact that the holding rods are guided by further guide elements along the flame tube in the direction of displacement.

An embodiment of the method that is advantageous for the function and reliable control is that the control device works passively, with a control mechanism responding to the pressure difference (Δp) in such a way that the pressure difference (Δp) drives an actuator and from this an orifice is moved, through which the clear flow width of the mixed air openings is varied depending on the load point over the load range in order to obtain optimum exhaust gas values.

Fig. 1

ein Gasturbinenbrennkammersystem im Längsschnitt mit einer schematisch dargestellten Regelvorrichtung für einen Luftmassenstrom,

Fig. 2

wesentliche erfindungsgemäße Komponenten eines Gasturbinenbrennkammersystems mit einem Flammrohr und einer Regelvorrichtung in perspektivischer seitlicher Ansicht,

Fig. 3

einen Ausschnitt des Gasturbinenbrennkammersystems in aufgeschnittener perspektivischer Ansicht teilweise von innen,

Fig. 4

einen vergrößerten Ausschnitt des Gasturbinenbrennkammersystems nach Fig. 3 mit einem Abschnitt einer Verstelleinheit im Bereich eines Stellglieds und

Fig. 5

ein Schaubild mit einem Verlauf von emittierten Schadstoffkomponenten über der Luftzahl λ bei verschiedenen Lastpunkten einer Turbine.

The invention is explained in more detail below using exemplary embodiments with reference to the drawings. Show it:

1

a gas turbine combustion chamber system in longitudinal section with a schematically illustrated control device for an air mass flow,

2

essential components according to the invention of a gas turbine combustion chamber system with a flame tube and a control device in a perspective side view,

3

a section of the gas turbine combustion chamber system in a cut-away perspective view, partially from the inside,

4

an enlarged section of the gas turbine combustion chamber system 3 with a section of an adjustment unit in the area of an actuator and

figure 5

a diagram with a course of emitted pollutant components over the air ratio λ at different load points of a turbine.

1 shows a combustion chamber system 1 (partially) in longitudinal section with an outer pressure housing 2, which is provided on the outside, towards the surroundings, on its front side with a front wall section which is formed by a burner flange 22, and on the peripheral side with an outer wall 20 (outer shell, preferably cast body ) and is surrounded on the inside by insulation 21. Inside the pressure housing 2, with its outside spaced apart from the inside of the insulation 21, a flame tube 34 is arranged, which is provided on its front side (input side) with a burner 31 and on its rear side facing away from the front side (outlet side) to a ( (not shown) turbine arrangement is connected or connectable via a coupling section designed for this purpose with coupling elements.

The space between the inside of the pressure housing 2 or the insulation 21 and the outside of the wall of the flame tube 34 is designed as an inflow channel 330 with a ring-shaped, in particular circular-cylindrical cross section, through which air compressed from the rear (outlet side) of the combustion chamber system 1 is fed to the Burner 31 can be fed in order to burn this introduced fuel in a combustion chamber 30 inside the flame tube 34 . In order to achieve the best possible flow conditions in the inflow channel 330, this is provided with an inflow tube 33, between the inside of which and the outside of the flame tube 34 the air is routed to the burner 31, as shown in 1 shown flow arrows.

Mixed air openings 320 are arranged in the flame tube 34 , preferably in an outlet section located on the outlet side behind the combustion chamber 30 , in particular behind a flame zone 32 (combustion zone) on the outlet side. These can e.g. B. equidistant from each other in the direction of rotation and z. B. in one or more to the longitudinal extent of the flame tube 34 perpendicular cross-sectional planes. Air from the compressed air mass flow introduced from the rear of the combustion chamber system 1 can be admixed to the combustion gases flowing inside the flame tube 34 from the inlet side to the outlet side via the mixed air openings 320 .

The combustion processes can be stabilized and optimized with regard to the emitted exhaust gas values via the mixed air component branched off from the supplied air mass flow, with the burner air component supplied to the burner over the load range of the associated gas turbine depending on the load point for specifying a suitable fuel/air ratio or the combustion air ratio (air ratio A) is set, as explained in more detail at the outset. For this purpose, the clear flow width through the mixed air openings 320 depends on the load point of the gas turbine by means of a control device via an actuating device 4 depending on the pressure difference Δp between the air pressure prevailing in the inflow duct 330 and the air pressure present in the area surrounding the combustion chamber system 1 .

In the present gas turbine combustion chamber system 1, in particular in the form of a micro gas turbine combustion chamber system (such a system is usually designed for burner power ranges from 10 kW to 1.5 MW and occasionally up to 2 MW), the control device has an actuating device 4 with a displaceable closing unit 40, which , as in the Figures 1 to 4 shown, is designed as an annular screen 400, similar to a cuff, and is provided with screen openings 401, the position and size of which are designed in such a way that they can be brought into alignment with the mixed air openings 320 as completely as possible, so that their clear flow width is as completely as possible or is at least largely available for the mixed air portion to pass through.

An advantageous detailed design of the control device with the closing unit 40 and a control unit with a control element that responds to the pressure difference Δp between the pressure in the inflow channel 330, in particular in its path for the branched-off portion of the burner air, and the ambient pressure on the outside of the pressure housing 2 is described in the 2 , 3 and 4 shown in more detail using an exemplary embodiment. In the embodiment shown, the mixed air openings 320 are designed as round mixed air bores; however, it is also conceivable to provide mixed air openings 320 with different geometric shapes, such as rectangular or non-symmetrical shapes, in order to suitably increase the clear flow width for achieving an optimal fuel/air ratio or air ratio λ for combustion and optimal exhaust gas values at the respective load point of the gas turbine vary.

The panel is moved by means of the actuator 43 by means of the outside along the flame tube 34 arranged support struts in the form of support rods 41, which directly responds to the pressure difference Δp and in the present case is designed as, in particular metallic, bellows 430 as a component that utilizes pressure. The closing unit thus consists of the displaceable panel 400, several retaining rods 41 and several metal bellows 430, the retaining struts being held in their relative position to one another in their front section facing away from the panel 400 by a circumferential stabilizing ring 42. The front end section of the retaining struts or retaining rods 41 protrudes through feed-through openings in the front wall section or the burner flange 22 into the interior of the associated bellows 430, which are aligned on the outside of the burner flange 22 with their longitudinal axis parallel or concentric to the retaining rods 41 and are attached. The holding rods 41 are slidably guided in the feed-through openings and can also be guided by further guide elements on the outside of the flame tube 34 . The front ends of the support rods 41 are fixed inside the bellows 430 via connecting portions to the front end walls thereof.

The interior of the bellows 430 is in pressure-equalizing connection with the inflow channel 330 via connection openings 220 present in the burner flange 22 or the front wall section of the pressure housing 2, so that inside the bellows 430 the respective (essentially static ) pressure prevails and thus the respective pressure difference Δp, which is dependent on the load point, sets in, as a result of which the bellows 430, which is designed in particular as metal bellows, is expanded against the spring force caused by its elasticity. As a result, the orifice plate 400 is displaced via the holding rods 41 as a function of the pressure difference Δp and the clear flow width for the mixed air portion through the mixed air openings 320 is regulated accordingly, so that the fuel/air ratio or the air ratio λ of the adapts given by the respective load point power requirement of the gas turbine, the change the clear flow width of the mixed air openings is set with regard to optimum exhaust gas values and combustion efficiency.

The bellows 430 consist of a high-temperature-resistant stainless steel and are designed for the progression of the existing pressure difference Δp between the combustion chamber 30 or the inflow channel 330 and the environment over the load range of the gas turbine. Since the pressure level in the combustion chamber is lower at part load than at full load, the bellows are expanded further at full load, so that the orifice plate 400 slides in the direction of the burner 31 . The result of this is that the unobstructed area of the mixed air openings 320 is smaller at full load than at part load, and a lower proportion of mixed air is therefore routed via the mixed air openings 320 . This increases the proportion of burner air at full load, which leads to a larger air ratio λ. Due to the interaction of the expansion of the bellows 430 and the resulting change in the unobstructed area of the mixed air openings 320, an approximately constant air ratio can be realized over the burner 31 for the entire load range of the gas turbine through the design of the control device with its components.

The stabilizing ring 42, which serves to stabilize the retaining rods 41 so that they can only move axially (in the direction of the longitudinal axis of the flame tube 34), also serves to limit the expansion (of the adjustment path) in the present case, so that the bellows 430 do not move can continue to expand as soon as the stabilizing ring 42 abuts the inside of the burner flange 22.

With the structure shown, a passively working, robust control device consisting of few components is achieved, which results in reliable, low-emission control of combustion in gas turbine combustion chamber systems, in particular micro gas turbine combustion chamber systems, over the entire load range.

Claims (15)

Gas turbine combustion chamber system (1), in particular micro gas turbine combustion chamber system, with - a combustion chamber (30), which has a longitudinally extending flame tube (34) surrounding a flame zone, which is provided with a burner (31) on its input side and is coupled or can be coupled to a turbine arrangement on its output side remote from this and in an outlet section is provided with mixed air openings (320), - with a pressure housing (2) surrounding the combustion chamber (30), between the inside of which and the outside of the flame tube (34) for supplying an air mass flow an inflow duct (330) is formed which leads from its output side to the input side, via which a proportion of mixed air via the mixed air openings (320) into the interior of the flame tube (34) and a portion of the burner air to the burner (31) for combustion with the fuel that has flowed in, and - with a control device via which the proportion of burner air supplied to the burner (31) can be regulated by varying the proportion of mixed air depending on the load point of the turbine arrangement by adjusting the clear flow width of the mixed air openings (320), characterized,
that the control device has an adjusting device (4) that responds to a pressure difference (Δp) between the inflow channel (330) of the air and the environment of the combustion chamber system (1), by means of which the clear flow width of the mixed air openings (320) depending on the load point, in particular continuously , can be reduced with an increasing load point and increased with a decreasing load point. Combustion chamber system according to claim 1,
characterized,
that the adjusting device (4) is constructed mechanically, the pressure difference (Δp) being used directly or indirectly as a drive source. Combustion chamber system according to claim 2,
characterized, that when the pressure difference (Δp) is used as an indirect drive source, there is a control unit with a pressure sensor, a converter unit and at least one control element (43) driven by this, by means of which the clear flow width of the mixed air openings (320) can be varied via a closing unit (40). , and that when using the pressure difference (Δp) as a direct drive source, the at least one actuator (43) itself is designed as a pressure sensor, by means of which the clear flow width of the mixed air openings (320) can be varied via the closing unit (40). Combustion chamber system according to claim 3,
characterized, that the adjusting device (4) has a bellows (430), in particular made of metal, as at least one adjusting element (43), which is firmly connected to the pressure housing (2) with its one front end area and with its other front end area spaced apart in the longitudinal direction a connecting section is connected via at least one intermediate member to the closing unit (40) comprising at least one closing element and that the interior of the bellows is connected to the air inflow duct (330) via at least one pressure equalization duct. Combustion chamber system according to claim 3 or 4,
characterized,
that the closing unit (40) is designed as a screen (400) which can be moved and/or adjusted in the circumferential direction by means of the actuator (43) in the longitudinal direction of the flame tube (34), more or less covering the mixed air openings (320) for varying the throughflow width is. Combustion chamber system according to claim 4 or 5,
characterized,
that the connecting section, the intermediate member and the closing unit (40) are rigidly connected to one another. Combustion chamber system according to one of claims 4 to 6,
characterized, that the pressure housing (2) has on its front side adjacent to the inlet side of the flame tube (34) a front wall section, on the outside of which facing the environment of the combustion chamber system (1) the actuators (43) are attached, and that several intermediate members running along the outside of the flame tube (34), in particular through the inflow channel (330), are designed as holding rods (41) which are connected to the closing unit (40) at their rear end area facing the outlet section of the flame tube (34). and are connected with their front end region spaced therefrom via the connecting section to the actuators (43) assigned to them. Combustion chamber system according to one of claims 5 to 7,
characterized,
that the closing unit (40) configured as a screen (400) is designed as a ring screen, which surrounds the flame tube in the area of the mixed air openings (320). (34) and extends axially over the flame tube (34) with a constant inner cross section adapted to the outer cross section of the flame tube (34) such that the clear flow width of the mixed air openings (320) exceeds the maximum change in the pressure difference (Δp) at least largely from can be varied from completely open to partially closed, the flame tube (34) having a constant external cross section over an axial extension section, at least in the region of the mixed air openings (320) and the displacement path of the ring diaphragm. Combustion chamber system according to claim 8,
characterized,
that the outer surface of the flame tube (34) has a circular cylinder shape at least over the axial extension section in the area of the mixed air openings (320) and the displacement path and the inner cross section of the ring diaphragm over its axial extension. Combustion chamber system according to claim 8 or 9,
characterized, that the flame tube (32) has a plurality of mixed air openings (320) in the circumferential direction, preferably equidistant from one another, for example arranged in the same plane or in several planes perpendicular to the axis of the flame tube and that the ring diaphragm has several diaphragm openings located in the same or in several diaphragm planes perpendicular to the axis of the flame tube, which are spaced apart in the circumferential direction according to the mixed air openings (320) and for the complete or at least extensive opening of the mixed air openings (320) with these at a minimum pressure difference (Δp) largely or completely in congruence and for the complete or at least extensive closing of the mixed air openings (320) at maximum pressure difference (Δp) can be brought as far as possible or completely out of congruence. Combustion chamber system according to one of claims 7 to 10,
characterized,
that the retaining rods (41), in their section projecting forwards over the burner (31), are guided through bores made in the front wall section of the pressure housing (2) into the interior of the bellows (430) assigned to them and are fastened to these via the respective connecting section. Combustion chamber system according to one of claims 7 to 11,
characterized,
that the retaining rods (41) are connected to a common, circumferential stabilizing ring (42), which forms a stop against the inside of the front wall section of the pressure housing (2) when the diaphragm (400) is adjusted in the direction of the minimum flow width or the closure of the mixed air openings (320). . Combustion chamber system according to one of Claims 7 to 12.
characterized,
that the retaining rods (41) are guided in the direction of displacement by further guide elements along the flame tube (34). Method for operating a gas turbine combustion chamber system (1), in particular a micro gas turbine combustion chamber system, according to one of the preceding claims, in which an air mass flow via an inflow channel (330) between the inside of a surrounding pressure housing (2) and the outside of a flame tube (34) from its outlet side supplied and divided by means of mixed air openings (320) arranged in an outlet section of the flame tube (31) into a mixed air portion, which is conducted behind a flame zone into the interior of the flame tube (31), and a burner air portion, which is fed to a portion on the inlet side of the flame tube (34 ) arranged burner (31) is supplied for combustion with fuel, wherein the The fuel/air ratio is controlled by varying the clear flow width of the mixed air openings (320) by means of a control device, characterized in that
that the clear flow width of the mixed air openings (320) is regulated as a function of the pressure difference (Δp) between the inflow duct (330) and the external environment of the combustion chamber system (1), in that the clear flow width decreases with an increase in the load point of a coupled turbine arrangement and with a Reduction of the load point is increased. Method according to claim 14,
characterized,
that the control device works passively, with a control mechanism responding to the pressure difference (Δp) in such a way that the pressure difference (Δp) drives an actuator (43) and this moves a diaphragm (400) through which the clear flow width of the Mixed air openings (320) is varied depending on the load point over the load range in order to obtain optimal exhaust gas values.

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