Patent Application
20170082023
The present invention relates to a method for operating a gas turbine engine unit comprising a gas turbine engine with at least a compressor section and a turbine section, wherein the compressor section is operable by a O2-rich first working fluid and wherein the turbine section is operable by a O2-lean working fluid, and further comprising a unit for an oxygen extraction process. The present invention further relates to a gas turbine engine unit embodied to perform the inventive method.
In a gas turbine engine a working fluid being compressed by a compressor enters a burner section where combustion of a mixture of the working fluid and a fuel occurs. The resulting combustion gas drives a turbine through the expansion and deflection of the gas through the turbine of the gas turbine engine. The turbine work or a part thereof, is transferred to the compressor through an interconnecting shaft. A combustion process with a complete burnout with low CO, NOx and unburnt hydrocarbons emissions is essential. Burners of the gas turbine engine are specifically constructed to perform such a combustion process. The working fluid entering the gas turbine engine has basically atmospheric oxygen (O2) content of about 21% O2. Hence, this amount of oxygen is present during the combustion process in the burner section and the burners are adapted to perform combustion with a working fluid comprising about 20% of oxygen. Since the burners can compensate slight variances of this oxygen content it is known to extract a small amount of working fluid beforehand of the combustion process to use it for an oxygen extraction process, wherein the O2 depleted working fluid is re-transferred to the burner section of the gas turbine engine for combustion. Currently only small amounts of the total working fluid can be separated for the oxygen extraction without affecting the combustion performance of the gas turbine negatively. Moreover, large scale air separation for oxygen production is currently performed by cryogenic processes which have high costs, large footprints and consume a high amount of electrical power.
U.S. Pat. No. 6,293,084 B1 discloses a gas turbine engine unit comprising a gas turbine engine with a compressor section, a combustion section, a turbine section and a bypass. Further, the gas turbine engine unit comprises a unit for an oxygen extraction process. This document also discloses a method for operating the gas turbine unit, wherein a part of an oxygen containing working fluid of the compressor section is discharged from the compressor section via the bypass to the unit for the oxygen ex-traction process.
Moreover, JP 2008 111419 A discloses a gas turbine engine unit comprising a gas turbine engine with a compressor section, a turbine section and a bypass. Further, the gas turbine engine unit comprises a unit for an oxygen extraction process and a combustion section. The latter document also discloses a method for operating this gas turbine unit, wherein all oxygen containing working fluid of the compressor section is discharged from the compressor section via the bypass to the unit for the oxygen extraction process and wherein an outlet of the combustion section connects the combustion section to a heat exchanger for pre-heating the oxygen containing working fluid on its way to the unit for the oxygen extraction process.
It is a first objective of the present invention to provide a method for operating a gas turbine engine unit resulting in a high amount of oxygen extraction in combination with a high efficient low emission combustion performance.
It is a further objective of the present invention to provide a gas turbine engine unit that can extract a high amount of oxygen combined with performing a high efficient low emission combustion.
These objectives may be solved by a method and a gas turbine engine unit according to the subject-matter of the independent claims.
Accordingly, the present invention provides a method for operating a gas turbine engine unit comprising a gas turbine engine with at least a compressor section and a turbine section and a combustion section with at least a combustion chamber, wherein the compressor section is operable by a O2-rich first working fluid and wherein the turbine section is operable by a O2-lean second working fluid, and further comprising a unit for an oxygen extraction process.
It is proposed that all O2-rich first working fluid of the compressor section is discharged from a compressor of the compressor section to the unit for the oxygen extraction process so that all O2-rich first working fluid of the compressor section is used for the oxygen extraction process, and O2 is extracted from the O2-rich working fluid by an oxygen extraction process.
Due to this, a high amount of oxygen can be produced and a high over all plant efficiency can be gained. Furthermore, a working fluid with a high enough O2 contend can be constructively easily used, especially, since a conventional turbine engine comprises a compressor section providing O2-rich working fluid. Hence, the O2-rich working fluid is compressed. Moreover, as a further result of the inventive method energy needed for the oxygen extraction process is gained from a fuel input instead of from power generation, like it is known from the state of the art cryogenic process. This is saving further costs. Thus, the proposed concept is extremely advantageous in terms of oxygen production and thermal efficiency compared to existing processes.
Even if the terms “compressor, combustion chamber, turbine, wall, bypass, outlet, return channel, inlet, sealing member, outer wall, inner wall, passage, casing, cavity, burner and membrane” are used in the singular or in a specific numeral form in the claims and the specification the scope of the patent (application) should not be restricted to the singular or the specific numeral form. It should also lie in the scope of the invention to have more than one or a plurality of the above mentioned structure (s).
A gas turbine engine unit is intended to mean a unit with at least a gas turbine engine and a unit for an oxygen extraction process. Further appliances, parts, assemblies or units may be also provided. In this context the gas turbine engine is the whole plant, with at least a compressor section and a turbine section. Furthermore, the gas turbine engine may also comprise a burner/combustion section. A unit for an oxygen extraction process may be any device or assembly adapted to perform an extraction or separation of oxygen. Especially, the extraction unit is an external unit from the gas turbine engine. It operates or functions with exception of the supplied working fluid independently from the gas turbine engine. A working fluid may be any medium or fluid feasible for a person skilled in the art containing oxygen and advantageously a gaseous working fluid, like air. “O2 rich” should be understood as with an oxygen content of about 18% to 30% and advantageously as with an oxygen content close to atmospheric or of approximately 20% to 21%.
Hence, by discharging all O2-rich first working fluid of the compressor section from a compressor of the compressor section to the unit for the oxygen extraction process a total amount of O2-rich first working fluid compressed in the compressor is discharged to or exits to the unit for the oxygen extraction process.
The gas turbine engine further comprises a combustion section with at least a combustion chamber. Furthermore, it is advantageous when the method further comprises the step of: Feeding to the at least one combustion chamber of the combustion section the O2-lean working fluid resulting from the oxygen extraction process. Thus, the working fluid can advantageously be cycled back to be used in the further process steps of the turbine engine. This reduces a need to freshly supply an equal amount of working fluid as that being withdrawn from the compressor section. In this context an “O2-lean” working fluid should be understood as with an oxygen content lower than the compressor feed stream or of about 10% to 16% or even less. Hence, the oxygen extraction process can extract up to 20% O2-content and normally at least about 10% O2-content. Generally, the extracted amount depends on the operating mode and what will be possible due to the process and the specifications of a used combustion system. The wording “resulting from the oxygen extraction process” should be understood as “processed by the oxygen extraction process”. A pressure level in the system especially before and after the oxygen extraction depends strongly on load, ambient conditions and the oxygen extraction process. An example for 100% load and 15° C. ambient air temperature would be 20.2 bar (a) pressure before O2 separation and 19.95 bar (a) after O2 separation.
Advantageously, the method further comprises the step of: Burning the O2-lean working fluid resulting from the oxygen extraction process in the at least one combustion chamber of the combustion section. This further reduces the need of additionally feed working fluid.
In an especially beneficial embodiment of the invention it is provided, that the method further comprises the step of: Expanding the burnt O2-lean working fluid through a turbine of the turbine section for producing electricity. Hence, the height of the invention is to gain a power production instead of power consumption while producing oxygen.
Thus, the method is realised by using a cycling path/arrangement that is adapted to supply a compressed O2-rich working fluid exiting the compressor section to an external unit for an oxygen extraction process and back feeding the O2-lean working fluid to the turbine engine or the combustion chamber of the combustion section, respectively, to be burnt therein. The advantage of this concept is to use all gas turbine engine compressor working fluid for the oxygen process enabling high oxygen production. Furthermore, leading the processed working fluid back into the gas turbine engine advantageously enables the full performance of the gas turbine engine cycle.
The method further comprises the step of: Cooling at least one wall of the combustion chamber of the combustion section by the O2-rich working fluid or by the O2-lean working fluid while bypassing the combustion chamber. Due to this, the combustion temperature can be advantageously reduced avoiding to high amounts of harmful combustion products like NOx. The cooling occurs before or after the O2 extraction process depending on the construction of combustion section of the gas turbine engine. It is very important to use the working fluid for cooling before the combustion to gain a good combustion. In case of a parallel cooling where cooling air enters through a combustor wall by film cooling, effusion cooling or similar, the process air would be lower and the flame temperature would be higher resulting in the production of more NOx. The use of the O2-rich working fluid as cooling medium is of high importance when integrating the gas turbine engine or its burner section, respectively, in the oxygen extraction process and especially when a gas turbine engine with modern performance data and high turbine inlet temperature is used. This cooling concept uses a serial cooled combustor, which is advantageous for complete burnout compared for example to parallel cooling where cold air enters through the wall creating a cold air layer.
Moreover, the method further comprises the step of: Heating the O2-rich working fluid or the O2-lean working fluid while bypassing the at least one combustion chamber. Hence, the radiated heat of the combustion chamber can be efficiently used to provide a temperature rise of the O2-rich working fluid, wherein the temperature rise is e.g. essential for the subsequent oxygen extraction process. This reduces the costs of the oxygen production and hence reduces the total price of obtained oxygen. Furthermore, space, pieces and costs of the gas turbine engine unit can be advantageously saved. The term “while bypassing” should be understood as “by bypassing”, “while passing by” or “while travelling along a passage adjacent to” here, the combustion chamber. Especially, the working fluid does not enter the combustion chamber and is not heated or burned in the combustion chamber.
The present invention further relates to a gas turbine engine unit comprising a gas turbine engine with at least a compressor section and a turbine section, wherein the compressor section is operable by an O2-rich first working fluid and wherein the turbine section is operable by a O2-lean second working fluid, and at least one bypass, and further comprising a unit for an oxygen extraction process.
It is proposed that the bypass is embodied in such a way that all O2-rich first working fluid of the compressor section is discharged from a compressor of the compressor section to the unit for the oxygen extraction process so that all O2-rich first working fluid of the compressor section is used for the oxygen extraction process, and wherein the unit for the oxygen extraction process is embodied in such a way to extract O2 from the O2-rich working fluid. In other words, a total or whole amount of O2-rich working fluid travels the bypass to be discharged from the gas turbine engine before the O2-rich working fluid is supplied to an extraction of O2 from the O2-rich working fluid by an oxygen extraction process.
Due to this, a high amount of oxygen can be produced and a high over all plant efficiency can be gained. Furthermore, a working fluid with a high enough O2 contend can be constructively easily used, especially, since a conventional turbine engine comprises a compressor section providing O2-rich working fluid. Hence, the O2-rich working fluid is compressed. Moreover, as a further result energy needed for the oxygen extraction process is gained from a fuel input instead of from power generation, like it is known from the state of the art cryogenic process This is saving further costs. Thus, the proposed concept is extremely advantageous in terms of oxygen production and thermal efficiency compared to existing processes.
As stated above, the gas turbine engine further comprises a combustion section with at least a combustion chamber. Advantageously, the compressor section of the gas turbine engine comprises at least one outlet and the combustion section comprises at least one outlet. According to another refinement, the bypass extends from the outlet of a compressor section of the gas turbine engine to the outlet of the combustion section. Due to this a direct passage for the working fluid can be provided. Further, this provides enough interaction area to heat the O2-rich working fluid and to cool the wall of the combustion chamber. An “outlet” should be also understood as an “exit”. Furthermore, the outlet from the compressor section is also an inlet into the combustion section, thus it is the connection area/region of both section.
It is furthermore provided that the outlet of the combustion section connects the combustion section to the unit for the oxygen extraction process. Hence, easy access for the O2-rich working fluid to the extraction unit can be provided. The unit for the oxygen extraction process may be in flow direction of the working fluid connected to the combustion section or its outlet, respectively, directly or via a connecting means like a duct or a channel.
A supply of the O2-lean working fluid can be provided constructively easy when the gas turbine engine unit comprises a return channel extending from the unit for the oxygen extraction process to an inlet of the combustion chamber of the combustion section. The return channel extends advantageously along a part of the combustion section before ending at the inlet of the combustion chamber. The O2-lean working fluid is led through the return channel to be burnt in the combustion chamber.
In a further realisation of the invention the combustion section comprises at least one sealing member separating the bypass and the return channel from each other. Thus, a mixing of the O2-rich working fluid and the O2-lean working fluid can be easily prevented. The sealing member may be any device feasible for a person skilled in the art, like a partitioning wall, or the like. Advantageously, the at least one sealing member is at least one wall of a combustion chamber of the combustion section that separates the O2-rich working fluid and the O2-lean working fluid. The construction has no direct flow connection between the compressor section and the turbine section besides the path via the bypass, the unit for the oxygen separation, the return channel and the combustion chamber.
Advantageously, the combustion chamber comprises an outer wall, an inner wall and a passage arranged between the outer wall and the inner wall, and wherein the O2-rich working fluid travels along the passage after entering the combustion section from the unit for the oxygen extraction process. According to this construction the O2-rich working fluid travels along a structure already existent in state of the art systems. Thus, mounting space and costs can be saved. Furthermore, the passage is a part of the return channel. The outer and the inner walls may be embodied as an inner and an outer liner of the combustor.
Alternatively, an O2-lean working fluid travels along the passage before exiting the combustion section through an outlet of the combustion section. Also in this construction state of the art structures can be used resulting in reduced mounting space and costs. Moreover, the passage is a part of the bypass.
Moreover, the combustion section comprises a casing and/or wherein the casing is provided with at least an outlet and at least an inlet to connect the combustion section with the unit for the oxygen extraction process. Hence, the connection between the gas turbine engine and the unit for oxygen extraction can be constructively easy realised. The at least one outlet and the at least one inlet are manifolds to connect the combustion section and the unit for oxygen extraction. The at least one outlet and/or the at least one inlet may be embodied as flanged holes.
Due to a further aspect of the invention the combustion section is an inline combustion section arranged axially between at least the compressor section and the turbine section of the gas turbine engine. Thus, a construction of a conventional gas turbine engine with a reconstructed housing/casing of the combustion section embodied with manifolds for the unit for the oxygen extraction process can be used in the inventive gas turbine engine unit. The combustion section is oriented basically along a flow direction of the working fluid.
Besides the axial or inline arrangement of the combustion section other arrangements of the combustion section are known. For example, it is known to arrange the combustion section in a non-inline configuration or perpendicularly arranged to an axis of the engine or as a so called single top mounted silo combustor as it is known e.g. from the Siemens SGT-2000E.
Alternatively, the combustion section comprises at least one single top mounted silo combustor, especially arranged basically perpendicular to an axis of the gas turbine engine. Due to this construction it is avoided that the cooling medium for blades and vanes will pass the components, like a membrane, of the unit for the oxygen extraction process. Further, a burner of the combustion chamber can have a higher residence time which results in better burnout and minimizes amounts of CO and unburnt hydrocarbons emissions. The flow direction of the working fluid in the combustion section is different as that in the compressor section and the turbine section, namely, they are basically perpendicular towards each other. In this context “basically perpendicular” means that the orientation of the combustor may deviate up to 30° from a strict perpendicular orientation.
A load and thermal symmetry for the gas turbine engine compared to the one silo embodiment can be provided when two basically symmetrically arranged side mounted silo combustors are provided. According to a feasible construction these would be mounted at opposes sides of the gas turbine engine.
According to a further realisation of the invention the combustion section and/or the single top or side mounted silo combustor comprises a first cavity and at least a second cavity, wherein the first cavity is the combustion chamber and the at least second cavity extends in at least one direction, advantageously a circumferential direction, all around an outer contour, advantageously a circumference, of the first cavity to build the bypass for discharging the O2-rich working fluid. Thus, the O2-rich working fluid can flow freely around the combustion chamber to be led directly to the unit for oxygen production and to be heated and at the same time cool the wall of the combustion chamber. Advantageously, the bypass is a basically circular passage, wherein “basically circular” is intended to mean that the bypass has a circular shape or a circular-like shape, like oval or egg-shaped.
Advantageously, the combustion section comprises at least one burner that is selected for combustion of an O2-lean working fluid. Hence, an efficient combustion process is achieved. The burner may be any burner feasible for a person skilled in the art, like a known standard lean premixed burner. Such a burner has millions of operating hours experience and compared to other state of the art burners it is a robust and simple burner with just two gas fuel lines, a pilot and a main flame. Possibly, the burner might be modified adjusted or e.g. by stabilizing a pilot fuel split. Advantageously, the combustion of the burner should have low NOx emission and a stable operation.
Generally, low oxygen content in the combustion working fluid slows down the combustion process increasing the risk for not complete burnout and high CO and unburnt hydrocarbons emissions. A long residence time is very important to achieve good burn out. According to another embodiment of the invention the at least one burner or specifically a combustor volume has a residence time that is between 20 milliseconds (ms) and 200 ms. For these times it had been shown that a complete combustion can be achieved even with low O2 content in the working fluid. A combustion volume means the whole volume of the combustor and of the transition. These volumes combined result in the residence time.
In a further aspect of the invention it is proposed that the unit for the oxygen extraction process comprises at least one ion transport membrane to perform the oxygen extraction process. This method has been shown to be easier to handle as existing cryogenic processes. Moreover, it may be a compact and space saving arrangement. Compared to existing cryogenic methods such an extraction is much more energy efficient. The ion membrane (s) together with the gas turbine engine produces electricity whereas the cryogenic method consumes electricity. Advantageously, the extraction unit comprises a plurality of ion transport membranes e.g. stacked to separate oxygen.
The above-described characteristics, features and advantages of this invention and the manner in which they are achieved are clear and clearly understood in connection with the following description of exemplary embodiments which are explained in connection with the drawings
The present invention will be described with reference to drawings in which:
The terms upstream and downstream refer to the flow direction of the airflow and/or working gas flow through the gas turbine engine 12 unless otherwise stated. If used and not otherwise specified, the terms axial, radial and circumferential are made with reference to a rotational axis 52 of the gas turbine engine 12.
In operation of the gas turbine engine 12, air, which is taken in through the air inlet 72 is compressed by the compressor section 14 and delivered to the combustion section or burner section 26. The compressed air passing through the compressor section 14 is an O2-rich working fluid 18 with about 21% O2 content. The combustion section 26 comprises one or more second cavities 60 each embodied as a burner plenum 76, one or more first cavities 58, each embodied as a combustion chamber 28 with a wall 32 encasing the combustion chamber 28 and exemplarily at least two burners 66 fixed to the combustion chamber 28. The second cavity 60 or the burner plenum 76, respectively, extends in circumferential direction 62 of the combustion section 26 all around an outer contour 64 or circumference of the first cavity 58 or the combustion chamber 28, respectively, to build a bypass 34 for the O2-rich working fluid 18 (see below). Thus, the combustion chamber 28 with the burners 66 is located inside one burner plenum 76.
The combustion section 26 or the burner plenum 76 comprises a casing 50 surrounding the bypass 34 and thus the combustion chamber 28. This arrangement forms or is a so called single top mounted silo combustor 54 that is arranged basically perpendicular to the axis 56 of the gas turbine engine 12. Thus, the O2-rich working fluid 18 travels along a direction oriented basically perpendicular to the axis 56 or in radial direction 78 and there is a major change in the flow direction of the working fluid 18.
As can be seen in
After traveling the compressor section 14 the O2-rich working fluid 18 enters a diffuser 80 of the compressor section 14 and is discharged from the diffuser 80 through an outlet 36 into the burner plenum 76 or the bypass 34, respectively. The bypass 34 extends from the outlet 36 of a compressor section 14 to an outlet 38 of the combustion section 26 arranged in its casing 50. The outlet 38 is for example embodied as a flanged hole. As can be seen in
The O2-rich working fluid 18 discharged from the diffuser outlet 36 flows in radial direction 78 and in circumferential direction 62 along the bypass 34 to the outlet 38 of the combustion section 26. The O2-rich working fluid 18 is heated while bypassing the combustion chamber 28, hence the bypass 34 is embodied in such a way to heat the O2-rich working fluid 18 that bypasses the combustion chamber 28. Simultaneously to the heating, the O2-rich working fluid 18 cools the wall 32 of the combustion chamber 28 while bypassing the latter and thus the overall temperature in the combustion chamber 28.
The heated O2-rich working fluid 18 exits the outlet 38 of the combustion section 26 and flows along a channel 82 connecting the gas turbine engine 12 or the combustion section 26 with the unit 22 for the oxygen extraction process. Thus, the bypass 34 is embodied in such a way to discharge a total amount of O2-rich working fluid 18 from the compressor 24 of the compressor section 14 to the unit 22 for the oxygen extraction process. The unit 22 for the oxygen extraction process is embodied in such a way to extract O2 from the heated O2-rich working fluid 18. Therefore, the extraction unit 22 comprises an ion transport membrane 70 and in this exemplary embodiment a stag of ion transport membranes 70 (not shown in detail) to perform the oxygen extraction process.
After the oxygen is extracted the now O2-lean working fluid 20 has an O2 content of approximately 10% to 16%. The gas turbine engine unit 10 comprises a return channel 40 connecting the extraction unit 22 and the gas turbine engine 12 and extending from the extraction unit 22 to an inlet 42 of the combustion chamber 28. The return channel 40 extends into an upper section 84 of the combustion chamber 28 while passing through an inlet 52 of the combustion section 26 located in its casing 50. The inlet 52 is for example embodied as a flanged hole. Hence, after the extraction process the O2-lean working fluid 20 flows back to the gas turbine engine 12 travelling the return channel 40 to enter the combustion chamber 28 through the inlet 42.
To separate the O2-rich working fluid 18 traveling the bypass 34 and the O2-lean working fluid 20 travelling the return channel 40 the combustion section 26 comprises a sealing member 44, like a sealing membrane, separating the bypass 34 and the return channel 40 from each other. The sealing member 44 is embodied by the wall 32 of the combustion chamber 28.
The O2-lean working fluid 20 entering the combustion chamber 28 or the burners 66, respectively, is mixed with a gaseous or liquid fuel. The air/fuel mixture is then burned and a resulting combustion gas 86 or working gas from the combustion is channelled via a transition duct 88 to the downstream turbine section 16.
The turbine section 16 comprises a number of blade carrying discs 90 attached to the shaft 74. In the present example, the turbine section 16 comprises two discs 90 each carry an annular array of turbine blades 92. However, the number of blade carrying discs 90 could be different, i.e. only one disc 90 or more than two discs 90. In addition, guiding vanes 94, which are fixed to a stator 96 of the gas turbine engine 12, are disposed between the turbine blades 92. Between the exit of the combustion chamber 28 and the leading turbine blades 92 inlet guiding vanes 94 are provided.
The combustion gas 86 from the combustion chamber 28 enters the turbine section 16 and drives the turbine blades 92 which in turn rotate the shaft 74. The guiding vanes 94 serve to optimise the angle of the combustion or working gas or fluid 86 on to the turbine blades 92. The compressor section 14 comprises an axial series of guide vane stages 98 and rotor blade stages 100.
The method for operating the gas turbine engine unit 10 comprises the following steps:
The O2-rich working fluid 18 is provided by the compressor 24 of the compressor section 14 and let through an outlet 36 of the compressor section 14 to the bypass 34. There the O2-rich working fluid 18 is heated while bypassing the combustion chamber 28. Simultaneously, the wall 32 of the combustion chamber 28 is cooled by the O2-rich working fluid 18 while bypassing. The bypass 34 discharges the total amount of O2-rich working fluid 18 from the compressor 24 of the compressor section 14 to the unit 22 for the oxygen extraction process. After leading the now heated O2-rich working fluid 18 via the outlet 38 of the combustion section 26 and the channel 82 to the unit 22 for the oxygen extraction process O2 is extracted from the heated O2-rich working fluid 18 by the ion transport membrane 70 of the extraction unit 22. Subsequently, the now O2-lean working fluid 20 is feed via the return channel 40 back to the combustion chamber 28 to be burnt with added fuel by the burners 66. The combustion volume 68, in other words, the combustion chamber 28 together with the transition duct 88 would have a residence time that is between 20 milliseconds (ms) and 200 ms.
For the burning of the O2-lean working fluid 20 the burner 66 is specifically selected and/or modified for combustion of the O2-lean working fluid 20. The burner 64 may for example be a lean premix type burner.
In
The embodiment from
After the oxygen extraction the now O2-lean working fluid 20 is led back to the combustion section 26a via a return channel 40 extending from the extraction unit to an inlet 42 of the combustion chamber 28a. An end section 108 of the return channel 40 extending from an inlet 52 of the casing 50 to the inlet 42 of the combustion chamber 28a and is embodied as a basically circular duct 110 extending in circumferential direction 62 around a burner arrangement 112, comprising a plurality of burners 64 (typically about 5 to 30). A sealing member 44 embodied as a partitioning wall 114 separates the duct 106 from the duct 110 and thus the bypass 34 from the return channel 40 to prevent a mixing of the O2-rich and the O2-lean working fluid 18, 20 in the combustion section 26a.
As can be seen in
Note that the casing 50 of the combustion section 26a in
The embodiments from
Referring now to
The now O2-lean working fluid 20 is led back to the combustion section 26b via a return channel 40 extending from the extraction unit to an inlet 42 of the combustion chamber 28b. The return channel 40 extends through an inlet 52 of the casing 50 of the combustion section 26b. An end section of the return channel 40 is the passage 48, hence the passage 48 is a part of the return channel 40 in the combustion section 26b. Thus, the O2-lean working fluid 20 travels along the passage 48 after entering the combustion section 26b coming from the extraction unit. While bypassing the combustion chamber 28b the O2-lean working fluid 20 is heated and simultaneously cools the inner and outer wall 32, 46 of the combustion chamber 28b and thus the overall temperature in the combustion chamber 28b. After entering the combustion chamber 28b the O2-lean working fluid 20 is burned with added fuel by a burner 66 of the combustion chamber 28b. Sealing members 44 embodied as partitioning walls 112 separate the bypass 34 from the return channel 40 in the combustion section 26b to prevent a mixing of the O2-rich and the O2-lean working fluid 18, 20.
A reversed flow path is shown in the embodiment of
While bypassing the combustion chamber 28c the O2-rich working fluid 18 is heated and simultaneously cools the inner wall 32 of the combustion chamber 28c and thus the overall temperature in the combustion chamber 28c. After flowing through the bypass 34 or the duct 118 and the passage 48 the O2-rich working fluid 18 exits the combustion section 26c through an outlet 38 in a casing 50 of the combustion section 26c. Hence, the O2-rich working fluid 18 travels along the passage 48 before exiting the combustion section 26c through the outlet 38. The bypass 34 discharges the total amount of O2-rich working fluid 18 from the compressor 24 of the compressor section 14 to the unit for the oxygen extraction process.
After exiting the combustion section 26c the heated O2-rich working fluid 18 travels a channel leading to the unit for oxygen extraction. There O2 is extracted exemplarily by an ion transport membrane (not shown).
The now O2-lean working fluid 20 is led back to the combustion section 26c via a return channel 40 extending from the extraction unit to an inlet 42 of the combustion chamber 28c and through an inlet 52 of the casing 50 of the combustion section 26c. To cross the duct 118 the combustion section 26c comprises through channels 120 connecting the return channel 40 and the inlet 42 of the combustion chamber 28c. After entering the combustion chamber 28c the O2-lean working fluid 20 is burned with added fuel by a burner 66 of the combustion chamber 28c. Sealing members 44 embodied as partitioning walls 114 and an outer wall 122 of the duct 118 separate the bypass 34 from the return channel 40 in the combustion section 26c to prevent a mixing of the O2-rich and the O2-lean working fluid 18, 20.
It should be noted that the term “comprising” does not exclude other elements or steps and “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.
Although the invention is illustrated and described in detail by the preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived therefrom by a person skilled in the art without departing from the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14170006.2 | May 2014 | EP | regional |
| 14190479.7 | Oct 2014 | EP | regional |
This application is the US National Stage of International Application No. PCT/EP2015/059858 filed May 5, 2015, and claims the benefit thereof. The International Application claims the benefit of European Application No. EP14170006 filed 27 May 2014 and to European Application No. EP14190479 filed 27 Oct. 2014. All of the applications are incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/059858 | 5/5/2015 | WO | 00 |
