JP4018809B2 - Additional combustion method using gas turbine exhaust gas and additional burner using this additional combustion method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a combustion combustion method for increasing the heat of GT exhaust gas by combustion using oxygen remaining in gas turbine exhaust gas (hereinafter abbreviated as GT exhaust gas), and a combustion burner using this method.
[0002]
[Prior art]
Since the GT exhaust gas after working with the gas turbine still has sufficient heat as a heat source for the boiler, it is supplied to the exhaust heat boiler without being discarded and used as a heat source. At this time, since oxygen remains in the GT exhaust gas, it is replenished by utilizing this, and the GT exhaust gas itself is reheated to increase the amount of steam generated as a higher-heat GT exhaust gas. Yes. The use of a duct burner has become the mainstream for tracking the GT exhaust gas. In this duct burner, a fuel supply pipe is arranged in a duct that guides GT exhaust gas to the exhaust heat boiler so as to be orthogonal to the GT exhaust gas flow, and is commemorated from a plurality of fuel injection holes toward the downstream side of the GT exhaust gas flow. It is provided to inject fuel. In this remedy burner, fuel is injected from the injection hole of the fuel supply pipe and the remedy is performed using oxygen remaining in the GT exhaust gas, so that the flow of the GT exhaust gas is adjusted and made uniform. A straight pipe is required.
[0003]
[Problems to be solved by the invention]
However, since the duct burner described above requires a straight pipe portion having a considerable length in order to sufficiently suppress the drift of GT exhaust gas in the duct, it takes up space, such as a gas turbine or a waste heat boiler. There is a problem that the arrangement of equipment is significantly restricted. In addition, when a sufficient straight pipe portion cannot be taken, mixing of the additional fuel and the GT exhaust gas is partially insufficient, a good combustion state cannot be obtained, and a desired heat increase may not be achieved.
[0004]
Further, the duct burner simply injects fuel into the flow of GT exhaust gas, so that combustion is likely to become unstable. In general, GT exhaust gas having an oxygen concentration of about 12 to 16% (WET) has its oxygen content. Only combustive combustion is possible in which the concentration drops to about 9%, and the amount of combustion cannot be increased without replenishing fresh air (air that has never been used for combustion). For this reason, the amount of heat obtained by additional combustion becomes insufficient, and sufficient heat increase of GT exhaust gas cannot be obtained. Therefore, there is a problem that it cannot cope with a case where a large amount of steam is required.
[0005]
Further, in this duct burner, since the amount of GT exhaust gas is overwhelmingly high and the oxygen concentration is low, the combustion amount is reduced (ie, the engine is turned down) because the combustion ratio is extremely poor due to the extremely excessive air ratio. Since the combustion becomes more unstable, the turndown ratio must be set to a small value of about 3 to 5: 1.
[0006]
Furthermore, recently, a chain cycle is often employed in which the surplus steam generated in the exhaust heat boiler is superheated and returned to the gas turbine to increase the rotational speed of the gas turbine. However, the oxygen concentration of GT exhaust gas when this chain cycle is used is often lowered to about 8% (WET) and the amount of water is also large. For this reason, it is difficult to perform additional combustion using only the residual oxygen in the GT exhaust gas, and after adding a large amount of fresh air to increase the oxygen concentration, additional combustion must be performed. The merit of additional combustion using residual oxygen is reduced. That is, it is difficult to realize reheating for increasing the heat of GT exhaust gas with a small amount of fuel.
[0007]
In addition, in order to ensure the amount of steam generated in the exhaust heat boiler even when the gas turbine is stopped, etc., normal diffusion combustion (fresh mode) is performed by using only fresh air without using GT exhaust gas in the combustion burner. Combustion) is required. However, if fresh air is allowed to flow in the duct burner instead of GT exhaust gas, a larger amount of fresh air than necessary is required, so that a large amount of energy is consumed to supply the fresh air and the overall efficiency is deteriorated.
[0008]
Then, an object of this invention is to provide the additional combustion method using GT exhaust gas which can implement | achieve a compact combustion facility, and the additional burner using this. Another object of the present invention is to provide a combustion combustion method using GT exhaust gas capable of further increasing the heat of GT exhaust gas and a combustion burner using the combustion combustion method. Another object of the present invention is to provide a combustion combustion method using GT exhaust gas capable of increasing the turndown ratio and a combustion burner using the combustion combustion method. Furthermore, an object of the present invention is to provide an additional combustion method using GT exhaust gas capable of additional combustion without using a large amount of combustion air, and an additional burner using the additional combustion method.
[0009]
[Means for Solving the Problems]
  In order to achieve this object, the invention according to claim 1AddIn the additional combustion method in which fuel is burned and GT exhaust gas is reheated, the additional fuel is supplied in two stages of primary fuel and secondary fuel, and an appropriate air ratio to the primary fuel in the first stage A quantity of combustion air is supplied to form a primary flame, while the second stage injects secondary fuel around the primary flameThen, NOx in the primary flame is reduced and burned by bringing the primary flame into contact with the secondary fuel.At the same time, GT exhaust gas is injected around the secondary fuel jet, and the remaining fuel in the GT exhaust gas is used to completely burn the secondary fuel.
[0010]
Therefore, in the first stage, the primary fuel is completely burned under an appropriate air ratio. Then, the secondary fuel supplied in the second stage is completely burned using the residual oxygen in a large amount of GT exhaust gas injected from the surrounding area. At this time, since the primary fuel burns at an appropriate air ratio, a large amount of NOx is generated. However, since NOx is reduced by contact with the secondary fuel, NOx generated in the primary combustion is reduced. On the other hand, the secondary fuel uses the low concentration oxygen remaining in a large amount of GT exhaust gas and burns completely under a super excess air ratio, so that the amount of NOx generated is small. In addition, since complete combustion is performed in the first stage and second stage combustion, the generation of CO can be suppressed. Therefore, the GT exhaust gas can be reheated with the calorific value obtained while keeping the generation amount of NOx low as a whole.
[0011]
Moreover, since fresh air with an appropriate air ratio that causes complete combustion is supplied to the primary fuel, the primary flame that stably burns functions as a flame holding source, and the GT exhaust gas with low oxygen concentration is overwhelming in the second stage. Even if a large amount of air is supplied and the state becomes super excessive air, the secondary fuel is stably and completely burned, and even if the turndown width is increased, the stability of combustion is not impaired.
[0012]
In addition, when increasing the amount of heat generated by increasing the amount of fuel to be injected, the primary flame using fresh air becomes the flame holding source, enabling stable combustion using GT exhaust gas. Remembrance combustion that lowers the oxygen concentration is realized.
[0013]
Further, the remaining additional fuel (secondary fuel) and the entire amount of GT exhaust gas are ejected from around the primary flame formed by freshly mixed fresh air and a part of the additional fuel (primary fuel). Therefore, even if these mixtures are affected by the drift of GT exhaust gas, etc., the secondary combustion will not become unstable.
[0018]
  Meanwhile, claims2The described exhaust gas burner using GT exhaust gas includes a fuel supply system that supplies the fuel in two stages of the primary fuel and the secondary fuel, and an amount of combustion air that has an appropriate air ratio to the primary fuel. Combustion air supply system for supplying to the burner throat and primary fuel injection in the burner throatTo form a primary flame under an appropriate air ratioPrimary fuel nozzles and secondary fuel around the primary flame downstream of the primary fuel nozzlesTowards the primary flame or in parallelA secondary fuel nozzle for injecting, and an exhaust gas nozzle for injecting gas turbine exhaust gas from the periphery of the secondary fuel nozzle into the combustion chamber of the remedy boiler in parallel with the primary flame,NOx in the primary flame is reduced and burned by bringing the primary flame into contact with the secondary fuel.The residual oxygen in the gas turbine exhaust gas is completely burned and combined with the primary flame, the gas turbine exhaust gas is reheated.
[0019]
Therefore, stabilizing the diffusion combustion of the secondary fuel injected around the stable flame that completely burns with fresh air in an amount appropriate for the primary fuel with the appropriate air ratio and the residual oxygen in the GT exhaust gas. Let That is, the additional combustion according to claim 1 is realized.
[0020]
Moreover, since the exhaust gas nozzle is installed around the primary flame with the injection axis facing the primary flame almost parallel to the primary flame, it is possible to secure the primary flame without the primary combustion cylinder that holds the primary flame. Can do. Therefore, the turndown ratio can be increased by stabilizing the combustion.
[0021]
Further, since GT exhaust gas is injected from the exhaust gas nozzle in parallel with the flame from the primary flame formed by the primary fuel and fresh air having an appropriate air ratio, the GT exhaust gas is rectified to some extent and drifted. And the mixing of combustion gas and GT exhaust gas is good.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings. FIG. 1 shows an embodiment of a combustion burner using GT exhaust gas according to the present invention, and the principle of a combustion combustion method using GT exhaust gas will be described based on this combustion burner. The exhaust gas burner 1 using GT exhaust gas burns additional fuel using oxygen remaining in the GT exhaust gas and reheats the GT exhaust gas itself. The exhaust fuel F is used as primary fuel F1 and secondary fuel. A fuel supply system 12 that is supplied in two stages of F2, a combustion air supply system 15 that supplies an amount of combustion air A in an appropriate air ratio to the primary fuel F1 to the burner throat 5, and a burner throat The primary fuel nozzle 10 for injecting the primary fuel F 1, the secondary fuel nozzle 11 for injecting the secondary fuel F 2 around the primary flame 2 on the downstream side of the primary fuel nozzle 10, and from around the secondary fuel nozzle 11 An exhaust gas nozzle 7 for injecting GT exhaust gas E almost in parallel with the primary flame 2 into a combustion chamber 18 formed in a combustion chamber or duct of a remedy boiler, and the residual oxygen in the GT exhaust gas E as secondary fuel F2 With It is full combustion, so that reheating the GT exhaust gas E in the secondary flame 3 generated at this time the primary flame 2.
[0027]
This memorial burner 1 is attached to the exhaust heat boiler 9 so that the burner tile front surface 8 is exposed inside the exhaust heat boiler 9, for example. As a result, the combustion burner 1 itself can be used as the combustion chamber 18 of the exhaust heat boiler 9 without providing a combustion chamber. Therefore, it is necessary to install a dedicated combustion chamber, a primary combustion cylinder or the like in the combustion burner 1. Therefore, the structure of the memorial burner 1 can be simplified. For this reason, since it is not necessary to perform construction according to the life of the refractory material such as the combustion chamber or the primary combustion cylinder, the maintenance cost of the remedy burner 1 can be reduced.
[0028]
The primary fuel nozzle 10 is disposed at the center of the burner throat 5 and is provided so as to inject the primary fuel F <b> 1 into the combustion air A ejected from the burner throat 5. The plurality of injection holes formed at the tip of the primary fuel nozzle 10 are opened so that the injection shaft of the primary fuel F1 extends obliquely forward. Thus, the primary fuel F1 is injected outward from the injection hole toward the combustion air A. Further, the primary fuel nozzle 10 is connected to the outside of the burner casing 13 by the primary fuel supply pipe 12 and receives the supply of the primary fuel F1.
[0029]
  The secondary fuel nozzle 11 is installed around the primary flame 2 on the downstream side of the primary fuel nozzle 10, and an injection hole is opened so as to inject the secondary fuel F <b> 2 toward the primary flame 2. One or more, preferably 2 to 4 secondary fuel nozzles 11 are arranged around the burner throat 5 so as to penetrate the burner tile 14. For example, in the case of the present embodiment, four secondary fuel nozzles 11 are arranged concentrically with the burner throat 5 at equal intervals. In this embodiment, the burner throat 5 is formed so as to be recessed upstream of the burner tile front surface 8 in the combustion air A, and the secondary fuel nozzle 11 is disposed around the burner throat 5. For this reason, the secondary fuel nozzle 11 injects the secondary fuel F <b> 2 into the exhaust heat boiler 9 at a position recessed upstream of the combustion air A from the burner tile front surface 8. The injection hole at the tip of the secondary fuel nozzle 11 injects the secondary fuel F2 toward the primary flame 2 and reduces the NOx generated in the primary flame 2 and then reduces the NOx generated in the GT exhaust gas E flowing around by the oxygen. It is set slightly inward so as to form the next flame 3. In the present embodiment, the injection hole of the secondary fuel nozzle 11 is formed inward, but this is not a limitation, and the injection hole is parallel to the injection axis of the combustion air A.ageMay be. Further, a slight gap 16 is provided between the secondary fuel nozzle 11 and the burner tile 14 so as to cool the secondary fuel nozzle 11 by flowing a part of combustion air A, for example, several percent. ing.
[0030]
The primary fuel nozzle 10 and the secondary fuel nozzle 11 are connected to a header (not shown) outside the burner casing 13 and connected to a fuel supply source (not shown). Then, the fuel F supplied from the fuel supply source is distributed to the primary fuel nozzle 10 and the secondary fuel nozzle 11 according to a predetermined distribution ratio and injected. In the present embodiment, the injection amounts of the primary fuel F1 and the secondary fuel F2 are both 50% by volume with respect to the total fuel F.
[0031]
The burner casing 13 includes an air damper 17 and a combustion air supply system 15 is connected via an air inlet. Inside the burner casing 13, the combustion air A flows to the exhaust heat boiler 9 side while cooling the air A along the secondary fuel nozzle 11 outside the guide cylinder 21. Further, the combustion air A is swirled by the swirler 19 and fed into the burner throat 5. The combustion air A is swirled by a swirler 20 installed around the primary fuel nozzle 10 and injected from the burner throat 5 into the combustion chamber 18 of the exhaust heat boiler 9. Here, the fresh air A supplied from the combustion air supply system 15 is an amount that provides an appropriate air ratio with respect to the primary fuel F1.
[0032]
Furthermore, a GT exhaust gas wind box 4 that takes in and rectifies the GT exhaust gas E is provided on the outer peripheral portion of the secondary fuel supply pipe 15. The GT exhaust gas wind box 4 is exposed to the exhaust heat boiler 9 with the end surface on the exhaust heat boiler 9 side being flush with the burner tile front surface 8, and is formed of a refractory material 28 for taking in the high temperature GT exhaust gas E. . The GT exhaust gas wind box 4 is provided with an intake port 22 for taking in the GT exhaust gas E and an exhaust gas nozzle 7 for ejecting the GT exhaust gas E around the primary flame 2. A duct (not shown) to which GT exhaust gas E is supplied from the gas turbine equipment is connected to the intake port 22.
[0033]
The exhaust gas nozzle 7 injects GT exhaust gas E substantially in parallel with the primary flame 2 to form the secondary flame 3. The exhaust gas nozzle 7 and the primary flame 2 around the primary flame 2 downstream of the primary fuel nozzle 10. It is installed with the injection axis facing in parallel. In the present embodiment, the exhaust gas nozzle 7 includes a plurality of through holes that pass through the refractory material 28 on the outer peripheral portion of the burner throat 5 and communicate the interior of the GT exhaust gas wind box 4 with the exhaust heat boiler 9. The through hole is formed in parallel with the injection axis of the burner throat 5 and is formed concentrically with the burner throat 5 as the center.
[0034]
In the present embodiment, since the burner throat 5 is formed at a position recessed upstream of the combustion air A from the burner tile front surface 8, the exhaust gas nozzle 7 is positioned downstream of the primary fuel nozzle 10. At the same time, it is installed around the primary flame 2 with the injection axis directed substantially parallel to the primary flame 2. For this reason, since the GT exhaust gas E is ejected as an axial jet on the side of the primary flame 2 substantially parallel to the primary flame 2, the GT exhaust gas E is prevented from being directly ejected toward the primary flame 2 to prevent the primary flame 2. It is possible to ensure the flame holding property. At the same time, the jet of GT exhaust gas E whose flow velocity is increased by the exhaust gas nozzle 7 makes the mixing with the primary and secondary combustion gases better. Thereby, since it is not necessary to provide a primary combustion cylinder for holding the primary flame 2, the structure of the remedy burner 1 can be simplified. In addition, since the thermal influence of the flames 2 and 3 is given only to the burner tile 14, the life of the refractory material other than the burner tile 14 can be extended.
[0035]
According to the combustion burner 1 using GT exhaust gas configured as described above, the combustion combustion using the GT exhaust gas E can be performed as follows.
[0036]
This memorial burner supplies the fuel F in two stages of a primary fuel F1 and a secondary fuel F2 from the fuel nozzles 10 and 11, and further supplies fresh air as an oxidant to the primary fuel F1 in the first stage. A is supplied from the burner throat 5 and the second stage secondary fuel F2 is supplied with the entire amount of GT exhaust gas E as an oxidant from the exhaust gas nozzle 7 to be subjected to two-stage combustion.
[0037]
In the first stage primary combustion, the primary fuel F1 and fresh air A in an amount corresponding to the primary fuel F1 are injected to form the primary flame 2. The appropriate air ratio (m) is usually about 1.1 to 1.2 for gas fuel and about 1.1 to 1.3 for oil fuel. In the case of the present embodiment, the distribution of the primary fuel F1 and the secondary fuel F2 is not particularly limited. For example, when the primary fuel F1 is set to 50% by volume and the secondary fuel F2 is set to 50% by volume, The amount of fresh air A is such that the air ratio is, for example, m = 0.6 with respect to the total amount of additional fuel supply F. In this case, since the air ratio of the fresh air A to the primary fuel F1 corresponds to the appropriate air ratio m = 1.2, the primary fuel F1 is completely combusted by the fresh air A and is stable without generating CO or the like. The primary flame 2 can be formed by combustion.
[0038]
In the second stage, the secondary fuel F2 is injected from the secondary fuel nozzle 11 toward the primary flame 2 or parallel to the primary flame 2. Thereby, since reduction combustion is performed around the primary flame 2, NOx generated by the primary combustion can be reduced and reduced. And GT exhaust gas E is ejected from the exhaust gas nozzle 7 further outside the secondary fuel F2. Thereby, the secondary fuel F2 is completely burned using the low concentration oxygen contained in the GT exhaust gas E. Since the GT exhaust gas E is injected almost in parallel with the primary flame 2, the secondary flame 3 can be formed around the primary flame 2 while holding the primary flame 2.
[0039]
Here, in this embodiment, the air ratio of the fresh air A to the total amount of the supplied fuel F is set to m = 0.6, but is not particularly limited thereto. It is preferable to reduce the amount of fresh air as much as possible in order to improve the efficiency of additional combustion. However, if the amount of fresh air is too small and approaches the theoretical amount of air, CO is generated due to incomplete combustion. The air ratio to F is, for example, in the range of m = 0.5 to 0.6 (corresponding to m = 1 to 1.2 in the air ratio to the primary fuel F1), more preferably 0.55 to 0.6 (primary fuel). The air ratio with respect to F1 may correspond to m = 1.1 to 1.2). In addition, a part of fresh air (usually about several percent) is generally used as cooling air for the secondary fuel nozzle, and substantially all of the fresh air and the primary fuel F1 are mixed. Although it cannot be said, the amount is negligible and does not substantially affect the proper air ratio.
[0040]
Even when the distribution ratio between the primary fuel F1 and the secondary fuel F2 is set to a ratio other than 50:50, for example, in the range of 70:30 to 30:70, the air ratio of the fresh air A to the primary fuel F1 is m = 1. The supply amount of fresh air A is set so as to correspond to about .about.1.2, preferably m = 1.2. Thereby, the primary fuel F1 can form the primary flame 2 with the fresh air A and can be burned completely.
[0041]
According to the combustion burner 1 using GT exhaust gas described above, the primary fuel burns at an appropriate air ratio, so that a large amount of NOx is generated along with stable combustion. However, the NOx is reduced by contact with the secondary fuel. Therefore, NOx generated in the primary combustion is reduced. On the other hand, the secondary fuel uses the low concentration oxygen remaining in a large amount of GT exhaust gas and burns completely under a super excess air ratio, so that the amount of NOx generated is small. In addition, since complete combustion is performed in the first stage and second stage combustion, the generation of CO can be suppressed. Therefore, the GT exhaust gas can be reheated with the calorific value obtained while keeping the generation amount of NOx low as a whole.
[0042]
Moreover, secondary combustion is performed by injecting secondary fuel and GT exhaust gas substantially parallel to the primary flame around the primary flame that is stably and completely burned under an appropriate air ratio. Even if a primary combustion cylinder for holding the flame is not provided, the primary flame functions as a flame holding source, and even if an excessively large amount of GT exhaust gas having a low oxygen concentration is supplied in the second stage and becomes in an excessively excessive air state. Even if the secondary fuel burns stably and completely, and the turndown width is increased, the stability of combustion is not impaired. Specifically, the turndown ratio can be improved to about 10: 1 when gas fuel is used and to about 8: 1 when liquid fuel is used.
[0043]
Even when GT exhaust gas from GT using a chain cycle is used, the secondary fuel F2 can be easily burned using oxygen of the GT exhaust gas due to the presence of the stable primary flame 2.
[0044]
In addition, when increasing the amount of heat generated by increasing the amount of fuel to be injected, the primary flame using fresh air becomes the flame holding source, enabling stable combustion using GT exhaust gas. Remembrance combustion that lowers the oxygen concentration is realized. Therefore, the amount of steam generated in the exhaust heat boiler 9 can be increased, and even when a large amount of steam is required, it can be easily handled.
[0045]
Further, the remaining additional fuel (secondary fuel) and the entire amount of GT exhaust gas are ejected from around the primary flame formed by freshly mixed fresh air and a part of the additional fuel (primary fuel). Therefore, even if these mixtures are affected by the drift of GT exhaust gas, etc., the secondary combustion will not become unstable. Therefore, the GT exhaust gas E can be injected in parallel with the primary flame 2 after having entered the wind box 4 from the side and rectified to some extent, and the duct of the GT exhaust gas E from the gas turbine equipment to the remedy burner 1 can be injected. Even if the shape (not shown) is bent, the influence of the drift can be suppressed. For this reason, the freedom degree of arrangement | positioning of gas turbine equipment or the memorial burner 1 can be made high.
[0046]
By the way, in order to ensure the amount of steam generated in the exhaust heat boiler 9 when the gas turbine equipment is stopped due to trouble or the like, it may be necessary to supply only the fresh air to the remedy burner 1 and perform the fresh mode combustion. . In this case, fresh air A having an air ratio of, for example, m = 1.15 is injected from the burner throat 5 to the total supply fuel F, and the total supply amount of the fuel F from each of the fuel nozzles 10 and 11. 50% by volume of the fuel F1, F2 is injected. This fresh mode combustion is performed by the principle of two-stage fuel combustion similar to a known low NOx burner. For this reason, in primary combustion, since it becomes super excess air combustion, generation | occurrence | production of NOx can be suppressed. In the secondary combustion, since the secondary fuel F2 can be completely burned using the combustion gas in the primary combustion, the generation of CO can be suppressed.
[0047]
When fresh mode combustion is carried out using the above-mentioned memory burner 1, when 13A gas is used as the fuel F, the oxygen content of the combustion gas is 5% and the NOx content is 60 ppm or less. I was able to. Similarly, when A heavy oil (N = 0.03 wt%) was used as the fuel F, the oxygen content of the combustion gas was 4%, and the NOx content was 80 ppm or less.
[0048]
Therefore, since the air ratio can be suppressed to about m = 1.15 when performing fresh mode combustion, the efficiency of combustion including the supply of fresh air can be made better than that of the duct burner.
[0063]
  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention.The
[0064]
  In addition,FruitIn formIsAlthough the memorial burner 1 using GT exhaust gas is directly installed in the exhaust heat boiler 9, the invention is not limited to this, and the exhaust burner 1 may be installed in a duct from the GT to the exhaust heat boiler 9. In this case, a fireproof wall or a water-cooled wall is provided inside the duct on the downstream side of the memorial burner 1. This also has the same effects as the remedy burner 1 of each of the embodiments described above, such that the combustion amount can be increased and the GT exhaust gas E can be reheated by stable combustion to increase the turndown ratio. Can do.
[0065]
In any of the above-described embodiments, the GT exhaust gas reheated by the combustor burner 1 is used in the exhaust heat boiler 9, but the present invention is not limited to this, and the GT exhaust gas is used in other equipment. Also good. In this case as well, the same effect as the remedy burner 1 of each of the above-described embodiments, such as being able to increase the amount of combustion and reheating the GT exhaust gas E by stable combustion to increase the turndown ratio, is achieved. Can do.
[0066]
【The invention's effect】
As is clear from the above description, according to the additional combustion method using GT exhaust gas according to claim 1 of the present invention, it is possible to reheat the GT exhaust gas while suppressing the generation of NOx and CO as a whole. . Moreover, since the primary flame that stably burns with fresh air under an appropriate air ratio functions as a flame-holding source, the secondary fuel can be used even if the GT exhaust gas with a low oxygen concentration is supplied in an overwhelming amount However, the stability of combustion is not impaired even if the turndown width is increased. Moreover, by stabilizing the combustion, it is possible to easily perform the combustion even when the GT exhaust gas from the GT using the chain cycle that is extremely difficult to burn with the duct burner is used.
[0067]
In addition, when increasing the amount of heat generated by increasing the fuel injection amount, stable combustion using GT exhaust gas is possible using a primary flame using fresh air as a flame holding source, and oxygen in the GT exhaust gas Remembrance combustion with lower concentration is realized. Therefore, it is possible to further increase the heat of the GT exhaust gas, and it is possible to easily cope with a case where a large amount of steam is required.
[0068]
Furthermore, since the GT exhaust gas is ejected from around the primary flame, a straight pipe portion for suppressing the influence of the drift of the GT exhaust gas is not required, and the size can be reduced.
[0074]
  Meanwhile, claims2According to the described memorial burner using GT exhaust gas, the memorial method according to claim 1 can be easily realized, and there are many effects of the memorial method. Further, the primary fuel and the secondary fuel are both completely burned while suppressing generation of NOx and CO as a whole, and the GT exhaust gas is reheated by using the primary flame that is most stably burned by fresh air with an appropriate air ratio as a flame holding source. Therefore, even if a large amount of GT exhaust gas with a low oxygen concentration is supplied overwhelmingly, the secondary fuel will burn stably even if it becomes an excessive air state, and the combustion will be stable even if the turndown width is increased. Sex is not impaired. Moreover,oneSince the next combustion cylinder is not required, the structure is simple and compact.
[0075]
In addition, since the GT exhaust gas is ejected from the exhaust gas nozzle so as to surround the primary and secondary flames, the influence of the drift of the GT exhaust gas can be suppressed, the flame is stabilized and the combustion gas and GT Mixing with exhaust gas is also good. And since the straight pipe part for suppressing the influence of the drift of GT waste gas is not required, an installation and piping can be made compact.
[Brief description of the drawings]
FIG. 1 is a central longitudinal cross-sectional view showing an embodiment of a memorial burner using the memorial combustion method using GT exhaust gas according to the present invention.The
[Explanation of symbols]
1 Commemorative burner using GT exhaust gas
2 Primary flame
3 Secondary flame
5 Burner Throat
6 Fuel nozzle
7 Exhaust gas nozzle
10 Primary fuel nozzle
11 Secondary fuel nozzle
23 Primary combustion cylinder
24 Primary exhaust gas nozzle
26 Secondary exhaust gas nozzle
29 Flame
A Fresh air (combustion air)
E GT exhaust gas
E1 Primary exhaust gas
E2 Secondary exhaust gas
F fuel
F1 Primary fuel
F2 secondary fuel

Claims (2)

In the combustion of additionally焚燃fee reheating add焚燃baked method gas turbine exhaust gas, the supplies separately add焚燃fee in two stages of primary fuel and the secondary fuel, to the primary fuel in the first stage An amount of combustion air that provides an appropriate air ratio is supplied to form a primary flame, while in the second stage, the secondary fuel is injected around the primary flame to bring the primary flame into contact with the secondary fuel. complete combustion of the secondary fuel with the remaining oxygen of the gas turbine exhaust gas by injecting the gas turbine in the exhaust gas around the jet of NOx was reduced combustion Rutotomoni its secondary fuel in the primary flame by causing A memorial combustion method using gas turbine exhaust gas. A fuel supply system that supplies the additional fuel in two stages of primary fuel and secondary fuel, and a combustion air supply system that supplies combustion air in an amount suitable for the primary fuel to the burner throat. When the primary fuel nozzle to form a primary flame under proper air ratio by injecting the primary fuel in the burner throat, the secondary fuel about said primary flame at a downstream side of the primary fuel nozzles the A secondary fuel nozzle that injects toward or in parallel with the primary flame; and an exhaust gas nozzle that injects gas turbine exhaust gas from the periphery of the secondary fuel nozzle into the combustion chamber of the remedy boiler in parallel with the primary flame, wherein by complete combustion with the remaining oxygen of the gas turbine in the exhaust gas causes the reduction combustion NOx in the primary flame by contacting said secondary fuel with said primary flame with the secondary fuel Add-fired burners of the gas turbine exhaust gas available, characterized in that reheating the gas turbine exhaust I following flame coupled with.

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