A method of burning fuel in compressed air

 

(57) Abstract:

A method of burning fuel in compressed air refers to the combustion of liquid or gaseous fuel into the compressed air in a gas turbine. The compressed air serves in moving along the axis of the thread. Thus at the beginning of the stream is separated many partial flows. To each of the threads separately sum of the fuel and burned in natural photoaparatom flame. The rest of the fuel down in various places to the stream. Distribute the flow uniformly. Formed due to the inhomogeneous distribution of the fuel in the stream has a local maximum at each of the pilot flame. Further, the fuel is ignited by the pilot flames and burn. This process contributes to the stabilization of combustion and to ensure that all the fuel is burnt. 4 C.p. f-crystals, 6 ill.

The invention relates to a method of burning fuel in the compressed air, which serves in moving along the axis of the stream, and initially separated from the stream lots of partial streams, each of which separately sum of the fuel and burned in the natural flow of the pilot flame, and the rest of the fuel is distributed in the stream, ignite the pilot plamenac and siovas between the compressor turbine part and a turbine part. The invention can also be used for burning fuel in the compressed air that flows between the two turbine parts corresponding gas turbine.

In serving to produce mechanical energy of a gas turbine, air is compressed in the compressor part to high pressure, then heated by supplying heat, usually by burning fuel, and, as a rule, mainly high pressure retain and, finally, expand in the turbine part. Combustion is usually produced in such a way that the gas is directed through the combustion chamber in which the burner or device from a variety of burners through which the gas is led to be burning fuel and ignite.

Examples of such burners follow from EP 0 193 838 B1, US patent Re. 33896, EP 0 276 696 B1, US patent 5 062 792, WO 92/19913 A1, as well as in other forms of execution from EP 0 210 462 A1, EP 0 321 809 A1 and EP 0 483 554 A1. The example used in the gas turbine combustion chamber with multiple burners follows from EP 0 489 193 A1. This combustion chamber has a circular annular space with the front wall, in which is fixed a burner, and a large part supplied for combustion of the compressed air is supplied through the burner into the annular space. Calceus the passage of air. The air entering the annular space through these slots, is used for cooling the inner wall and outer wall. The combustion chamber is located between the compressor part and a turbine part of a gas turbine. Before the stream is compressed in compressor parts air enters the combustion chamber, it is repeatedly rejected and loses turbulence, which he probably had when leaving the compressor part, at the latest at the entrance to the combustion chamber. Each burner on its side gives the partial gas stream that passes through it, is known for the turbulence, but that does not leads to the fact that the gas stream receives the twist axis. By performing the combustion chamber and relatively complex flow out of the pressure loss to a significant extent; in addition, since the thread loses the turbulence, which may have been communicated to him in a compressor part, at the entrance to the turbine part of the thread again must be reported to the turbulence, which requires a considerable expenditure on equipment and entails further pressure drop.

An example of a combustion chamber in which the flow of compressed air must be supplied with turbulence, it follows from EP 0 590 297 A1. This document, although it does not provide od is upravleniya flow through the combustion chamber with preservation of turbulence it should contain is usually provided at the inlet of the turbine part of the stationary idler.

Appearance and, how is burned in the compressed air stream, are dependent on many components, which describe the flow. In particular, when the flow moves relatively quickly occurring in the combustion may be prone to instabilities, which are expressed in the increased production of harmful substances and can lead to complete cessation of combustion. Burning for a short time, which must occur in a relatively fast current thread is in any case very desirable to suppress the formation of oxides of nitrogen, which is installed by itself, arising from the combustion of high temperatures, without going into the details of what is happening during the combustion reaction. For the beginning of the formation of nitrogen oxides is required only the excess of oxygen in the resulting combustion flue gas, which, however, always takes place in a gas turbine. Small time flow when there is obviously a high temperature is unequivocal small formation of nitrogen oxides. Described only that the issue receives under certain circumstances a higher weight, if down stream with the twist, as at any given time a thread spends this tre is Otsego invention lies task, indication of the method of the above kind, which is constantly guaranteed the stability of combustion.

To solve this task according to the invention features a method of burning fuel in the compressed air, which serves in moving along the axis of flow at which the first stream is separated multiple partial streams, each of which separately sum of the fuel and burned in the natural flow of the pilot flame, and the rest of the fuel is distributed in the stream, ignite the pilot plamenac and burn, and the rest of the fuel is distributed in the flow is inhomogeneous so that the formed due to this, the distribution of the fuel stream has a local maximum at each of the pilot flame.

In the sense of the invention refused the customary practice of the separation of air flow, which must be combusted fuel into many partial flows and leading to each of these partial flows more or less separately heat; the main load of the combustion takes place according to the invention without separation of the stream into multiple partial streams. Part of the flow of course is separated and divided into partial flows, and these partial streams are used for education pilot plamenno distributed in the stream. The distribution of the fuel flow is purposefully heterogeneous so that each pilot flame is a local maximum of the distribution. The heterogeneity of the distribution of fuel flow ensures that each pilot flame is relatively rich mixture of fuel and air which can be ignited readily and reliably; in this sense it is not desirable according to the usual understanding of the heterogeneity in the distribution of fuel contributes to the stabilization of combustion and to ensure that all the fuel is burnt.

Separated from the partial flow flows have such options and are supplied with the appropriate quantity of fuel to obtain stable under all possible circumstances combustion; in particular, for this combustion is possible to form a relatively rich mixture of fuel and air. The rest of the fuel is fed directly to the stream, and the resulting mixture is on average relatively poor, as required under the normal operating conditions for the gas turbine. According to the available excess air may under certain circumstances adversely affect the combustion and requires on-the possibility of further measures to stabilize si pilot Empire, which act as ignition sources and ensure that it is immediately made to flow the fuel ignites and completely burned.

The compressed air stream can, if necessary, to have a twist axis, which, in particular, is preferred in the gas turbine; and it may fall guiding devices, which should resolve may occur in the compressor part of the swirl flow, and the gas turbine can be made easier. In addition there may be no guiding device at the inlet gap of the gas turbine, which would create turbulence required for rotating turbine component parts for their functioning; even if a complete rejection of the guide devices is not always possible, the guide device can however be made more simply, since the thread is already part of the necessary turbulence and should deviate less than usual.

The preferred image of the portion of the stream from which otvetst partial flows, before offshoot eliminate turbulence, particularly preferably completely eliminated. Elimination of turbulence is related to the slowdown is occurring during braking, the pressure is at the proper execution of the guides of the device is large enough to form a pilot flame, so do not should provide any additional blower or similar device.

Especially preferred is the use of the method in a gas turbine, and the flow is supplied from the compressor of the gas turbine and after combustion of the fuel supplied to the turbine part of a gas turbine. With further advantage of the guide vanes in the inlet gap, through which the stream was flowing to the turbine portion, provided in such number and located so that the local maximum is heterogeneous because of heterogeneous distribution of fuel temperature distribution in the stream is located, respectively, between the two guide vanes. This, in particular, can be achieved by the fact that the number of pilot Empire coincides with the number of vanes, and that the pilot flame and guide vanes considering the swirl flow properly positioned relative to each other.

Examples of the invention follow from the drawings. In the drawings, refused to view parts that are not important for the explanation. While the drawings should not be considered as corresponding to the zoom view Gania fuel into the compressed air in axial longitudinal section;

Fig. 2 is a cross section through the same device, as indicated by the line II-II in Fig. 1;

Fig. 3 - tangential section through the same device, as indicated by the line III-III in Fig. 2;

Fig. 4 is a cross section through the device according to Fig. 1, as indicated by the line IV-IV in Fig. 1;

Fig. 5 is a cross section through the use of the device edge to supply several different types of fuel;

Fig. 6 - device with two systems for fuel.

Match the parts have the same reference position; therefore, in the subsequent explanation, makes a General reference to figures 1 to 4.

In particular, from figure 1 you can see the neckline of the gas turbine, and it is located between the compressor part 4 and the turbine part 5 of the combustion chamber with the surrounding ring axis 1 of a gas turbine annular space 6. From the compressor portion 4 is supplied with a flow of 2 compressed air, which is moving along the axis 1 and thereby relative to the axis 1 of the turbulence. Property that thread 2 has a twist planned symbolizing his curved arrow. Thread 2 pervades mostly unobstructed annular space 6 comfortably space 6 surrounding the rotor 23 of the gas turbine. To prevent the flow 2 flowed along the rotor 23, between it and the inner wall 12 introduced the sealing device 24, for example, the labyrinth seal. Subject to burning fuel down through the supply system 8. Most fuel thus flows to the ribs 7 and passes through a provided in each rib 7 of the nozzle 9 in thread 2, where it is ignited and burns. The fuel is completely burned before thread 2 through the inlet gap 14 will be included in the turbine portion 5 and reach provided there guide vanes 15. To induce and stabilize the combustion summed up through the fins 7 of the fuel, and to an additional branch to the air for cooling the inner wall 12 and outer wall 13, more or less directly behind the compressor part 4 in the annular space 6 is an annular pipe 16. Part of the air flows in a circular pipe 16 and branched out there into multiple partial streams 3. One of these partial flows 3 through the corresponding cooling piping 19 falls beyond the inner wall 12 and outer wall 13 of the annular space 6 and can cool it. The other partial stream 3 flows to the pilot burner 10. This pilot sarcasti fuel supplied to the pilot burner 10 or respectively provided many pilot burners 10 and there burn mainly with the air, which lead through partial stream 3. Thus, it is possible to adjust the mixing ratio of fuel and air, in particular, to a value that ensures a constant and stable combustion. This stabilizes the combustion fuel combustion, which down through the rib 7. Of course, that the pilot burner 10 and the rib 7 depending on the execution tangentially offset relative to each other; in this sense, visible from figure 1 location is not representative. Received in the annular pipe 16 part of the thread 2 gets first deflector vanes 17 and there is declined so that the originally available distribution is lost. This deviation is associated with a known braking and hence the resulting increase in static pressure and thereby substantially stabilizing the partial threads 3. Rejected deflecting vanes 17 part stream 2 enters into a collecting space 18, where branches of the partial flows 3. The location of the rib 7 at the rear of the pilot burner 10 is not required; the provisions of the ribs 7 and the pilot burner 10 along axis 1 should be selected in accordance with the proportions of the flow. Is it possible that the pilot burner 10 and the rib 7 is necessary. motri also figure 6

Figure 2 shows, in which spatial terms are relative to each other, the ribs 7 of the annular space and guide vanes 15 in the turbine part 5, in the form of a cross-section perpendicular to the axis 1, which is visible in the shape of a cross. The curved arrow represents the twist of the thread 2. It is seen that the same number of vanes 15 and the ribs 7, and it is also seen that the ribs 7 and the guide vanes 15 in a certain way azimuthal offset relative to each other. If this offset respectively to the turbulence of the flow 2 is chosen correctly, then the maximum of the temperature distribution in the stream 2, which is obtained in place because of heterogeneous distribution of fuel turned out to be a local maximum of the distribution of fuel, comes to the position exactly between the two guide vanes 15 and may thereby contribute to thermal discharge guide blades 15.

How can be done this thermal discharge guide blades 15, it follows from figure 3. There tangential section through presented on figure 2 in the cross section of the device in accordance with the line III - III on figure the e temperature in thread 2, when it flows away from the ribs 7 and the combustion is completed. The temperature T is plotted in dependence on the coordinates x, which should be measured perpendicular to the stream 2. It is seen that the local maximum temperature T lies between the guide blades 15, and the temperature of stream 2 near the guide vanes 15 in comparison with its maximum is clearly reduced. From the point of view of thermodynamics for flowing in a gas turbine process is significant average temperature averaged across the stream; due to the inhomogeneous temperature distribution due to the geometry of the location of the ribs 7 can be achieved that the guide vanes 15 is loaded not the average temperature or even higher temperatures, as is clearly reduced compared with the mean temperature. Considering the fact that among other things, limit the permissible thermal load available materials determines the maximum temperature at the entrance to the turbine part 5, using the advantages of the invention can be achieved by significantly increasing this maximum.

From figure 3 visible design of the ribs 7. The ribs 7 are hollow, and the inner space 8 refers to systematically extent arbitrarily be distributed along the edges 7; it is not necessary to provide a nozzle 9 only at the ends of the ribs on the side of ettekanne. The only essential criterion for the location of the nozzles 9 is that must be attained desired in the sense of the invention, the heterogeneity of the distribution of fuel flow 2.

Figure 4 shows the location of the annular pipe 16 for branches of the partial flows 3 piping cooling 19. You can see also deflecting blades 17, which rejects incoming ring pipe 16 part stream 2 in the direction of the axis, and to some extent slow down, in order to increase the static pressure in the partial flows 3.

Figure 5 shows a cross section through the rib 7, which is executed with a possibility of choice of different types of fuel. Inside the ribs 7 are three of the fuel channel 20, 21 and 22, and the smallest of the fuel channel 20 serves to supply oil, medium fuel channel for supplying natural gas, and the largest fuel channel for supplying gaseous fuel with low calorific value, for example, coal gas. Each fuel channel 20, 21, 22 included in the corresponding nozzle 9.

Figure 6 shows the interaction of aleipata in the combustion chamber, moreover, the ribs 7 and the pilot burner 10 are streamed by thread 2. According to the representation of the flow 2 flows directly. The figure also fair to thread 2, which flows with turbulence, and then of course the ordinate should be different than in the case of stream 2, the current without turbulence, not parallel to the axis 1, and along the stream and, accordingly, in a spiral around the axis 1. The abscissa in the figure in any case is the azimuthal angle, which should be measured around the axis 1. Each pilot burner 10 fail (not shown) branched from the flow 2 is a partial flow of air mixed with also supplied with fuel, and burned with the formation jutting out into the stream 2 pilot flame 25. Pilot burner 10 is formed so the first step for applying heat to the stream 2. The second step for supplying the heat given by the ribs 7, from which the thread 2 is directly fed to the fuel. When each of the ribs 7, the fuel flows in the direction approximately perpendicular to the stream 2 and is distributed along the illustrated dotted lines flow line 26. Due to the location of the ribs 7 distribution of fuel flow 2 is heterogeneous, and it is marked on the chart in the upper part of the figure. Accordingly, two fuel flow from the neighboring Islands, in which the fuel ignites, respectively, on a pilot flame 25. Along the dotted fronts flame 27 burning in the stream 2 covers causes, finally, complete combustion is fed through the ribs 7 of the fuel. The chart in the upper part of the figure plotted the distribution of 28 fuel; the abscissa plotted azimuthal angle on the ordinate plotted concentration. The ordinate is shown in broken lines, to symbolize that the graphical representation shows only the shape of the distribution 28 and is not intended as a quantitative statements. Distribution 28 corresponds approximately to the distribution of the fuel line that connects the tops of the pilot Empire with each other. Distribution 28 is in close connection with the temperature distribution in the stream, as explained in the example of figure 3; the higher local concentration of fuel, the above is also achieved when the combustion temperature. It should be noted another advantageous form of the further development of the invention according to the figure 6: this form further development is that as the guide vanes 15 (compare figure 3), and the ribs 7 and the pilot burner 10 are provided respectively in the same number.

Soglasno gas turbine and ensures rapid and complete combustion.

1. The method of burning liquid or gaseous fuel into the compressed air in a gas turbine, which serves in moving along the axis (1) flow (2), which from the beginning of the thread (2) separate lots of partial flows (3), each of which individually take part fuel and burned in jutting out into the stream (2) pilot flame (25), and in which the rest of the fuel down in various places to the stream (2), ignite pilot flames (25) and burn, characterized in that what the rest of the fuel through the inlet in a variety of locations distributed in the stream (2) is not uniform, and formed due to this distribution (28) fuel flow (2) has a local maximum (29) at each of the pilot flame (25).

2. The method according to p. 1, wherein the flow (2) has a swirl about the axis (1).

3. The method according to p. 2, in which part of the stream (2) from which otvetst partial flows (3), before branching partial flows (3) eliminate the turbulence.

4. The method according to one of the preceding paragraphs, in which the stream (2) is supplied from the compressor part (4) of the gas turbine and after combustion of the fuel supplied to the turbine part (5) of the gas turbine.

5. The method according to p. 4, wherein the flow (2) flow to turbinova in the stream (2) there is an inhomogeneous temperature distribution, having local maxima, each of which lies between the two guide vanes (15).

 

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