JPH07507863A - catalytic combustion - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] catalytic combustion The present invention relates to catalytic combustion, and more particularly to catalytic combustion, such as occurs in gas turbines. The present invention relates to a catalyst structure for use in a process.

Catalyst bodies for use in such processes support a catalyst active in the combustion process. structures, such as foams or honeycombs, having or including passages through them; can include. In any combustion process, one or more of such catalyst bodies The above assembly is used. In catalytic combustion processes, the fuel/air feed material at temperatures below that at which spontaneous ignition occurs, typically between 2 and 4 degrees absolute The hot gas stream is passed through the catalyst assembly where combustion takes place at an overpressure within the range of get. The fuel may be either a gas or a liquid at ambient pressure and temperature; Most, if not all, of the fuel is at the temperature that supplies the fuel/air mixture to the catalyst body. It should be in a gaseous state at certain temperatures and pressures. Examples of suitable fuels include natural gas , propane, naphtha, kerosene and diesel distillates. at least of fuel Some are raw materials from catalytic autothermal steam reforming carried out on hydrocarbon feedstocks.

Can be an acid. Carbonization to produce gas turbine feedstock The process describing the use of catalytic autothermal steam reforming of hydrogen feedstock is It is described in Patent Application Publication No. 351094.

Catalytic combustion processes, such as those that occur in gas turbine applications, typically involve at least one If the catalyst is “lit-off”, very high gas velocities This is a problem in maintaining combustion. Exit the catalyst passage during normal operation. The gas preferably has a linear velocity of 25 to 150 m/s, especially 50 to 100 m/s. do. As the flow rate increases, the rate at which heat is lost from the catalyst surface to the gas increases. Burning The rate at which materials are transported to the catalyst surface also increases as the gas velocity increases. The catalyst burns Heat is released at the surface of the catalyst if it is active enough to burn the fuel. The rate at which the gas flows increases as the gas velocity increases. Therefore, the catalyst is sufficiently active. , then both the heat release rate and the heat loss rate increase as the gas velocity increases. As the temperature rises, the surface temperature of the catalyst changes only slightly, if at all. do not have. As the gas velocity increases further, the flow rate eventually reaches a point where the reaction rate no longer increases. a dynamically limited situation is reached. When the flow rate increases further , the temperature of the catalyst surface decreases as the heat loss increases. This is combustion on the catalyst surface. The rate is reduced and the temperature is further reduced until a point is reached where combustion can no longer be sustained. cause below.

The temperature at which combustion is no longer sustained depends, for example, on the nature of the fuel in the combustible mixture. It depends on a variety of factors, such as concentration, gas velocity, and the nature and concentration of the catalyst. [thing The switch from mass transfer to dynamic control is not as sharp as implied from the above. In fact, the net effect is the sum of the limitations imposed by mass transfer and reaction rates. ].

Unfortunately, available catalysts that can withstand the temperatures normally accelerated by gas Inadequate to allow operation at the gas flow rates normally desired in turbine operation. have sufficient activity: i.e., the desired flow rate is greater than the flow rate at which combustion is sustained. Hey. In some cases, catalysts that can withstand the temperatures normally accelerated are “light-off” of the catalyst or complete conversion at preheating temperatures It has insufficient activity to do so. sufficient to carry out combustion at low temperatures. , some catalysts with high activity also exist, but these active catalysts are usually accelerated tends to sinter and/or evaporate at temperatures that limit catalyst life. be done.

These problems can be solved by increasing the temperature at which the fuel and air are supplied to the combustion equipment. , can be overcome to some extent. Therefore, if the feed temperature is high enough It is possible to maintain combustion even at high gas flow rates. But enough It is often impractical to supply a high temperature fuel/air mixture to the fuel/air mixture.

Fuel/air mixtures are typically created by compressing air and then adding fuel under pressure into this compressed air. produced by adding. This fuel/air mixture is fed into the combustion device using compressed air. 250-450 °C, especially 300-4 It is usually preferred to supply at a temperature within the range of 00°C.

Our European patent, currently published as European Patent Publication No. 491481 In patent application no. 91311042.5, we present a method to overcome this difficulty. A portion of the fuel/air feed is catalytically combusted in the precatalyst, resulting in high temperatures (h ate) the gas stream is then mixed with the remainder of the feedstock, and then the mixture is combusted. Describe the method. Combustion of the mixture of the hot gas stream and the remainder of the fuel/air feed is the primary Combustion takes place in a catalytic body or if the mixture is hot enough. It is homogeneous, i.e. it is carried out in the gas phase. European Patent Publication No. 491481 is the combustion path where combustion is maintained and produces a hot gas flow, and the remainder of the fuel/air feed. the use of one or more precatalyst bodies with a catalyst-free bypass passage through which was taken into consideration.

In this arrangement, the fuel/air feed material passing through the combustion path of the precatalyst is combusted. The catalyst body relatively close to the entrance of the combustion path reaches the adiabatic flame temperature, but the burning fuel/ The average temperature of the air feed gradually increases until it reaches the adiabatic flame temperature before leaving the combustion path. Get out. However, this requires that the catalyst be able to withstand adiabatic flame temperatures. This places restrictions on the catalysts that can be used. European Patent Publication No. 4 In No. 91481, combustion paths are distributed in clusters over the entire cross section of the preliminary catalyst body. , but each such raster has a substantial connection to the adjacent bypass. It is recommended in Europe that a sufficient number of combustion paths should be included so that heat losses are avoided. It was considered in Patent Publication No. 491481.

In U.S. Pat. No. 4,870,824, only a portion of the passageway has a catalyst in the passageway wall soil. , by forming the catalyst unit in the shape of a honeycomb in which the adjacent passages do not contain a catalyst. Therefore, it has been proposed to suppress the temperature of the catalyst. During operation, heat is transferred to the catalyst-containing strands. Heat is transferred from the burning path to the adjacent bypass; this heat transfer is caused by the fuel passing through the bypass. Dual role of performing preheating of the air feed and reducing the temperature experienced by the catalyst in the combustion path Therefore, it is possible to use catalysts and catalyst supports that do not have high temperature stability. become. During transit through such bypass, the fuel/air supply The feed material is heated sufficiently so that gas phase combustion occurs downstream of the catalytic unit.

The honeycomb passage wall increases the ignition delay time of the hot fuel/air mixture passing through it. According to a suitable honeycomb design, the ignition delay time in the passageway can be increased. The temperature in the bypass path is such that the ignition delay time is such that essentially no gas phase combustion occurs. The gas leaving the passageway has a very short ignition delay time, so Gas phase combustion occurs essentially immediately downstream of the catalyst body. The design of this catalyst body so that combustion within the reactor proceeds to a very high conversion rate, for example over 80%. can be placed. This is done by fresh catalyst before the gas mixture leaves the combustion path. Catalyst bodies can be designed to achieve sufficiently high conversion rates such as So this brings stability in driving. Catalysts become inactive over time , i.e., as the catalyst "ages", the position at which such high conversions are achieved is moves toward the exit, even if it remains in front of the exit of the combustion path. Achieving high conversion rates It also means that variations in fuel and/or air flow can be adjusted. all aisles In a normal honeycomb, where is the combustion path, when the catalyst is fresh, the gas outlet temperature is can be controlled to a desired level below the adiabatic flame temperature, but with catalyst aging and , air and fuel flow fluctuations cannot be easily adjusted. In addition, the normal In NECAM, under pressure, the surface temperature of the catalyst quickly rises to the adiabatic flame temperature, resulting in The catalyst deactivates quickly.

A combustion path and a catalyst-free buffer that transfers heat from the combustion path. When using this type of combustion catalyst assembly, where there is an is not heated to flame temperature, allowing for higher adiabatic flame temperatures than would otherwise be possible. It becomes possible to use fuel/air mixtures with Therefore, the large amount of fuel Mixtures containing concentrations become available. As fuel concentration increases, catalyst light decreases. This is advantageous because toe-off is easier. air/fuel mixture As the adiabatic flame temperature increases, the catalyst activity requirement decreases.

Related to the design and operation of catalytic combustion units for applications such as gas turbines Another problem encountered was at low loads, i.e. when the gas turbine "turns down". When the fuel is in the "n-dovn" or "idling" state, It is often difficult to arrange so that the charring is maintained. adjacent combustion When a gas phase reaction occurs due to heat transfer from the passageway across the passageway wall, but is still within the passageway. The above method of preheating the gas in the bypass passage to a temperature that is suppressed by the catalyst stable operation with respect to aging, fuel and air flow fluctuations, and “turndown” We have now realized that this allows for the design of systems that are easily achieved.

Therefore, the present invention has (a) a plurality of through passages, some of which come into contact with the passage wall soil. a combustion path having a catalyst, at least a portion of which does not contain a catalyst and is adjacent to said combustion path; (b) a catalytic combustion unit that is a bypass preheating path in contact; (b) the combustion path and the (C) means for supplying a first gas stream containing air and fuel to the Ipass preheating path; (d) a second combustion zone downstream of said catalytic combustion unit; (e) means for supplying a second gas stream; (e) into said second gas stream upstream of said afterburn zone; and means for introducing a variable amount of fuel.

The present invention also provides (a) a plurality of through passages, some of which have a combustion catalyst in the passage wall soil; a combustion path, at least a portion of which does not contain a catalyst and is adjacent to said combustion path. The combustion path of the catalytic combustion unit which is a bypass preheating path and the bypass preheating path providing a first gas stream comprising air and fuel, thereby causing combustion of the fuel to occur in the combustion chamber; The heating process is carried out in the preheating path, with heat being transferred through the passage walls to the adjacent bypass preheating path. The air and fuel passing through the bypass preheating path are preheated, and the air and fuel are passed through the bypass preheating path. The combustion of fuel is carried out downstream of the combustion path and the bypass preheating path, and producing a stream of hot combusted gas; (b) introducing air into the stream of hot combusted gas; (C) adding a second gas stream to the hot combusted gas; and varying the amount of fuel added to the second gas stream before adding the fuel to the second gas stream. A baking method is also provided.

Fuel passing through the combustion path as described in said U.S. Pat. No. 4,870,824. burns catalytically, but some of the heat generated passes through the passage wall and into the adjacent non-catalytic bypass passage. and heat the gas passing through these bypass passages. As stated below Additionally, catalytic combustion can be carried out in several stages. Burnt gas and heated bypass The resulting mixture with gas is determined by the temperature and composition of the gas entering the passage, the bypass passage and the combustion passage. temperature determined by the relative proportion of gases passing through the have a degree.

The combustion passages are preferably arranged individually in the catalyst body; that is, each wall of the combustion passage is It has a non-catalytic bypass path on the other side. Thus, preferably each catalyst containing The twist firing path is surrounded by a non-catalytic bypass preheating path. Or, however, less preferred No, but the combustion passages are clustered and each combustion passage has at least one adjacent bypass. It has a path. Therefore, there is no combustion path that is completely surrounded by adjacent combustion paths. There will be no. Each bypass passage is preferably small (each with one adjacent combustion passage). This ensures that the flammable mixture passing through each bypass is preheated. This is because The combustion channels are preferably arranged regularly over the cross-section of the catalyst body. . The bypass preheating passage and the combustion passage may be the same size or different sizes.

As mentioned above, some of the fuel/air mixture passing through the combustion path and the adjacent non-catalytic bypass Catalytic combustion with a portion of the fuel/air mixture passing through the hot path can be carried out in several stages. can. This can ensure that the initiation and maintenance of catalytic combustion is facilitated. Therefore, it is preferable. Therefore, each has a catalyst-containing combustion path and an adjacent non-catalytic bypass. using one or more catalyst bodies in series, including a preheating path and a mixing zone between each catalyst body. can be provided. The ratio of bypass preheating path to catalyst-containing twisting path varies from catalyst to catalyst. can be done. In addition to the bypass path adjacent to the combustion path of the catalyst body, Another bypass for supplying the fuel/air mixture to the mixing zone between the downstream catalytic body and the It can be provided with a means for For example, such additional bypass means may be Bypass preheating path as described in European Patent Publication No. 491481 through the first catalyst body and optionally an intermediate catalyst body or can be a passageway extending through the catalyst body, so that some of the air/fuel mixture passes through the catalyst body. take a detour. In this case, the air/fuel stream passing through such additional bypass Preferably, little or no compound preheating track originates from the combustion path or bypass preheating path. stomach. A series of catalyst bodies can be used to minimize the length of the catalyst assembly. If the flow through the catalytic body is turbulent, at least after the first catalytic body, is preferable. one or more catalysts having both a combustion passage and an adjacent bypass preheat passage; After passing through the medium passage, the uncowbusted fuel, i.e. The fuel in the gas that passes through the bypass preheating path is combusted to produce a hot stream of burned gas. Jiru. If this hot combusted gas stream is not diluted by the addition of coolant gas , the hot combusted gas stream has a temperature that corresponds to the adiabatic combustion temperature of the fuel/air mixture. has.

This combustion occurs catalytically, meaning that all of the passages are catalyzed by catalysts that remain active even at high temperatures. preferably in a non-contact manner. homogeneously, i.e. in the gas phase.

If there are two or more catalytic combustion stages, i.e. a combustion path and a bypass preheating path. and/or bypass preheating if there are two or more catalyst bodies having both If the combustion of unburned fuel in the gas passing through the passageway is carried out catalytically, one or more The catalyst used in the upstream stage can be different from the catalyst used in one or more downstream stages. Ru. Therefore, a catalyst used in one or more downstream stages may be used in one or more upstream stages. catalysts in one or more upstream stages. It is not necessary to have great low temperature activity.

For example, if unburned fuel in the gas that has passed through the bypass preheating path undergoes catalytic combustion, , the catalyst used in this step is a noble metal from group VIII of the periodic table or a metal of such metal. Preferably, it does not contain any compounds. Suitable catalysts include mixtures of rare earth oxides, especially , as described in European Patent Publication No. 472,307. There is a mixture of ntana and praseodymia. other suitable Suitable catalysts include perovskite and manganese-substituted aluminium. There is barium acid. However, the catalyst in the combustion path of the upstream stage is a group VIII noble metal or can include compounds of precious metals. In reality, the catalyst in the combustion path is platinum, Preferably, it contains palladium and/or rhodium, or a compound thereof. difference Furthermore, the combustion catalyst in these combustion paths corresponds to the adiabatic flame temperature of the fuel/air mixture. Since it is not necessary to withstand high temperatures, the catalytic converter used in the subsequent catalytic combustion of the heated mixture A material with lower heat resistance than the medium, such as cordierite or The catalyst body can be constructed from metal. Compared to carriers that have to withstand All in all, such carriers can withstand thermal shocks, i.e., those that occur when the system is started or shut down. The use of such carriers because they can easily withstand rapid temperature changes such as is advantageous.

Temperature of the mixture of burned gas from the combustion path and hot unburned gas from the bypass path is above the temperature at which gas-phase combustion, that is, homogeneous combustion of the fuel can be maintained, but the catalyst below the temperature at which rapid inactivation of the catalyst or melting or softening of the catalyst support occurs. It is preferable to design the system as follows. Also, as mentioned above, this temperature is Specifically, the ignition delay time of the unburned fuel/air mixture in the bypass passage is reduced by the passage wall. Compared to the ignition delay time when the bypass passage is not surrounded by There is no ignition delay time that occurs essentially immediately upon exit from the bypass path. selected as follows.

Under normal operating conditions, i.e. once starting has been achieved, the combustion path and a bypass passage in which the amount and temperature of air supplied to the combustion catalyst system are essentially constant. preferably maintained at Provision is made to control the temperature of the gas exiting the catalyst body; This temperature is therefore monitored by a suitable sensor and applied to the catalyst body, i.e. A sensor determines the amount of fuel in the fuel/air mixture supplied to the combustion path and the bypass path. It is preferred that the outlet temperature changes in response to the Yes. In this way, after start-up, the catalyst system operates under essentially constant conditions.

Air is included in the high-temperature combusted gas stream produced by catalytic combustion and subsequent gas-phase combustion. A second gas stream is added. At least under non-idling conditions, this second gas Add to the stream. The amount and temperature of this second gas flow are determined under the desired idling conditions. The temperature of the mixture of the second gas stream and the hot combusted gas stream is such that gas phase combustion of the fuel is maintained. The amount and temperature should be such that the temperature exceeds the In some cases, idli If the fuel can be present in the second gas stream when operating under Thus, in one form of the invention, fuel is mixed with compressed air and the resulting fuel/air A portion of the mixture is placed next to the combustion path of the catalytic unit as a first gas stream, as described above. In addition to the adjacent bypass passage, the remainder is used as a second gas flow.

Under load conditions other than idling, the fuel (or is larger if some fuel is added to the second gas stream under idling conditions. When mixed with the hot combusted gases introduced into the second gas stream, this additive fuel The combustion of the fuel produces a hot product gas which is used to drive the turbine.

However, under idling conditions, there is no fuel in the second gas stream and this The inlet temperature is the same as the temperature at which the gas stream is supplied for catalytic combustion (101 et temperature ature) is preferred.

When the system changes from idle to full load, the amount of air in the second gas stream changes from 1 to the second gas stream. The amount of fuel added to the gas stream can vary, but the amount of air used is essentially one. Preferably, it is constant. The amount of air added to the catalytic combustion and used as the second gas stream The amount of air being removed is obtained from the same source (e.g. a compressor) and at the same temperature. L) is conveniently supplied to the system. of the total air used as the second gas stream. The ratio 1 is preferably determined by the geometry of the system, and any characteristics In order to vary this ratio of 1 volume to 1 volume of a fixed system, for example variable baffles or springs can be used. It is preferable not to provide a twist such as (vane). Therefore, the second gas The proportion of air used as flow L1 is preferably determined by the fixed geometry of the system, The hydraulic resistance of the flow path determines the rate of second gas flow. Therefore, idling and full Control of operation between the load and the load is achieved by varying only the amount of fuel added to the second gas stream. It is preferable that the

As mentioned above, two or more contacts may be used to facilitate starting and/or maintaining combustion. Preferably, an array of media is used. The need for such a catalyst array depends on specific design conditions. Depends on the matter. Therefore, when using high air compressor outlet temperatures, This can reduce such problems. Similarly, in some cases, upstream of the catalyst assembly to preheat the incoming air or air/fuel mixture. Viloft flame, preferably lean burn n-burn) may also be provided. In addition, catalysts exhibiting hysteresis, That is, it requires a specific inlet temperature to achieve light-off, but if the inlet temperature The light also goes off when the temperature drops below the light-off temperature (but remains slightly lower). The use of state-maintaining catalysts aids in stability.

Next, two embodiments of the present invention will be described by way of examples with reference to the accompanying drawings. In the accompanying drawings, FIG. 1 schematically shows a first embodiment with an assembly of three catalyst beds. (not to scale); FIG. 2 is a cross-sectional view taken along line ll-11 of FIG. Figures 3 and 4 are cross-sectional views of the first and third catalyst bodies of the Figure 1 assembly. Yes; FIG. 5 is a diagram similar to FIG. 1 showing the second embodiment.

In a first embodiment, the device has an inlet zone 11 at one end and an outlet zone 12 at the other end. The outer cylindrical casing 10 includes an outer cylindrical casing 10. A casing inlet zone in the casing 10 and A tubular sleeve 13 is arranged between the outlet zones 11.12 by means not shown. . Inside the sleeve 13 there are formed a row of three cylindrical catalyst bodies 14, 15, 16, which There are bands 17, 18. between the catalyst bodies. Between the casing inlet zone 11 and the first catalyst body 14 between the sleeve inlet zone 19; between the third catalyst body 16 and the casing outlet zone 12; A sleeve combustion zone 20 is included. There is a gap between the sleeve inlet zone 19 and the catalyst body 14. A hole baffle 21 is present. The space between the outer casing 10 and the sleeve 13 The gas forms an annular bypass 22 . In the total cross-sectional area inside the casing 10, the annular bar The cross-sectional area of the path is 6%, and the cross-sectional area of the sleeve 13 is 3%. Keishi Means (not shown) are provided for supplying a flow of compressed air to the fuel injection zone 11. Injection means are provided for injecting the sleeve inlet zone 19 and the annular bypass 22 respectively. 23.24. Fuel supplied to the annular bypass 22 via injection means 24 Valve means 25 are provided for varying the amount.

The first catalyst body 14 has a cross-sectional area of 91% of the total cross-sectional area within the casing 10. It has several 26 through holes of 20 mm diameter spaced in an equilateral triangular pattern. Includes a 9Qmm long cordonite honeycomb. The number of holes 26 and their spacing are The total cross-sectional area of 26 is determined to be 21% of the total cross-sectional area within the casing 10.

Although seven holes 26 are shown in FIG. 2, the actual number used is the total cross-sectional area within the casing 10. Depends on. These holes 26 are provided by hydraulic diameter 1.1 mm through passages. Surrounded by a honeycomb-shaped region 27 with a voidage of 75%. be caught.

The inner surface of the alternating honeycomb passages in region 27 is alumina wash coat. and impregnated with palladium as a combustion catalyst. Therefore, 50% of the NECOM passage is the catalyst-containing combustion passage 28 (denoted as “C” in Figure 3), each combustion passage. 28 is surrounded by a non-catalytic bypass preheating path 29 (denoted as "Bo" in FIG. 3).

A baffle 21 spaced apart from the surface of the catalyst body 14 has a tubular protrusion 30; The tubular protrusion 30 corresponds to the hole 26 and the perforation 31, These are aligned in precise relation to the sleeve inlet zone 19 to direct the gas to the space between the baffle 21 and the honeycomb region 27 of the catalyst body 14. Ru.

The second catalyst body 15 has a length of 190 mm and a honeycomb shape extending over its entire cross section. Ru. This honeycomb shape is the same as the shape of the honeycomb region 27 of the catalyst body 14. That is, the porosity is 75%, and the passages with a hydraulic diameter of 1.1 mm and the alternating passages are filled with catalyst-containing fuel. They are a burning path and a non-catalytic bypass preheating path. The third catalyst body 16 has a length of 200 mm and a contact Like the medium 15, it has a honeycomb shape over its entire cross section. honeycomb passage has a porosity of 75% and, like the catalyst body 14.15, has a hydraulic diameter of 1. It has 1mm Ru. However, in the catalyst body 16, only 37.5% of the passages are catalyst-containing combustion passages ( i.e. 3 passages in each group of 8 passages). The catalyst containing passage 28 contains two catalysts. Arrange the channels so that they are not adjacent to each other. Figure 4 shows the appropriate shape of this honeycomb. In FIG. 4, "C'" means a combustion path containing a catalyst, and "B" means a combustion path without a catalyst. means preheating path.

In normal operation, air at 300°C is pumped at 10 bar absolute and 100 kg/s (case per m2 of the total internal cross-sectional area of the casing into the casing inlet zone 11. 27% of the air passes through the annular bypass 22 and the remaining 73% passes through the three It is calculated when entering the block entrance zone 19. The through hole 31 of the baffle 21 Due to the hydraulic resistance between 89% of the total amount of air supplied to the casing inlet zone 11 is 65% of the total amount of air supplied to the casing inlet zone 11 6 and only 11% of the total air is supplied to the casing inlet zone 11. The size is such that 8% of the volume passes through the passages of the honeycomb region 27.

Fuel (e.g. natural gas) enters the catalyst body 14 from the injector 23 The air mixture has a composition such that combustion of all the fuel produces a gas mixture at 1200°C. 95% of the fuel entering the combustion path 28 of the catalyst body 14 is supplied at such a rate that If it is assumed that combustion occurs while passing through a combustion path such as The temperature of the hot gas stream leaving 27, i.e. passing through the combustion passage 28 of the honeycomb region 27, The combusted gas and the heated but unheated gas that passed through the bypass passage 29 of the honeycomb region 27 It is calculated that the temperature of the gases of combustion will be at a temperature of 746°C. Through hole 26- The passing gas enters the sleeve inlet zone 19 at essentially the same temperature as that supplied to the sleeve inlet zone 19. Enter 7. Hot gas flow from honeycomb region 27 passes through holes 26 in band 17. mixed with the unreacted fuel/air mixture resulting in a gas mixture at a temperature of 351°C. .

This gas mixture then passes through the catalyst body 15. through the catalyst-containing combustion path of the catalyst body 15. Assuming that 90% of the fuel/air mixture in the combustion chamber burns during passage through these combustion paths, If so, the gas entering the zone 18 between the catalyst bodies 15 and 16, i.e. the combustion of the catalyst body 15, The burned gas that has passed through the burning path and the heated gas that has passed through the non-catalyst bypass path of the catalyst body 15 The mixture with the added gas is calculated to have a temperature of 748°C.

The gas mixture from zone 18 then passes through catalyst body 16. Gas entering the combustion path containing catalyst If we assume that 89% of the gas is combusted during passage through these combustion paths, the sleeve combustion Contact with the gas entering the burning zone 20, that is, the burned gas that has passed through the combustion path of the catalyst body 16. The medium 16 passes through non-catalytic bypass paths and is heated during passage through these bypass paths. It is calculated that the mixture with the natural gas has a temperature of 904°C, which is To maintain homogeneous (i.e. gas phase) combustion of methane-containing fuels such as gas The temperature is sufficiently high. However, this temperature limits the range of high surface-to-capacitance ratios (i.e. The ignition delay time in the honeycomb passage (within the honeycomb passage) is such that the gas mixture is low enough to be long enough for essentially no homogeneous combustion to occur. .

However, the ignition delay time at this temperature is low in the region of low surface-to-capacity ratio (i.e., downstream of the sleeve combustion zone 20), the gas mixture is produced in the sleeve combustion zone 20. ・A high-temperature gas of 1200°C combusts instantaneously and enters the casing outlet zone 12. short enough to produce a stream of gas.

The air (which amounts to 27% of the total air volume supplied to the casing inlet zone 11) is supplied to the annular via It passes through pass 22 and is essentially unheated from its inlet temperature of 300°C.

Fuel is added to this air passing through the annular bypass 22 from the injector 23. If not, the gas flow produced in the sleeve combustion zone 20 is in the zone 12 (), It is mixed with the air passed through the annular bypass 22 to produce a gas mixture at a temperature of 950°C. arise. This air that has passed through the annular bypass 22 is injected with fuel from the injector 24. If added, when mixed with the gas mixture from the sleeve combustion zone 20, the case The mixture in the singe exit zone 12 is hot enough to burn homogeneously.

The second embodiment shown in FIG. 4 is similar to the embodiment of FIG. 3 catalyst bodies are not present in this case. In this second embodiment, the annular bypass 22 has a cross-sectional area corresponding to 17% of the total internal cross-sectional area of the casing 10, and the catalyst body 14 The holes 26 have a total cross-sectional area corresponding to 10% of the cross-sectional area within the casing 10.

The annular bypass 22 is provided with a restriction 32 .

Similar to the FIG. 1 embodiment, the honeycomb passages of each catalyst body 14.15 are 75% void. Rate, 1. It has a hydraulic diameter of 1 mm and only the alternating passages have a catalytic coating. this In an embodiment, catalyst bodies 14 and 15 are 130 mm long and 190 mm long, respectively. has.

The orifice 32 of the annular bypass 22 is designed to block air at 300° C. during normal operation. against bar, a speed of 100 kg/s (per 1 m2 of the total internal cross-sectional area of the casing) 43% of the air is supplied to the casing inlet zone 11 at The remaining 57% enters the sleeve entrance zone 19. buff The through hole 31 of the honeycomb area 21 provides hydraulic resistance between the baffle 21 and the passageway of the honeycomb region 27. Therefore, 42.5% of the total amount of air supplied to the casing inlet zone 11, that is, 42.5% of the total air amount supplied to the casing inlet zone 11, Approximately 75% of the air entering the reeve inlet zone 19 passes through the holes 26 and enters the casing inlet zone 1. 1, i.e. only about 14.5% of the total amount of air supplied to sleeve inlet zone 19 enters sleeve inlet zone 19. The honeycomb region 27 is sized so that approximately 25% of the air passing through the honeycomb region 27 passes through the passages.

Methane-containing fuel (e.g. natural gas) is transferred from the injector 23 to the catalyst body 14. Combustion of the entire fuel/air mixture entering produces a gas mixture at 1400°C. 90% of the fuel entering the combustion passage 28 of the catalyst body 14 is added at a rate such that the composition ．． If it is assumed that 5% is burned during passage through such a combustion path, the catalyst body 14 The temperature of the hot gas stream leaving the honeycomb region 27 of will be at a temperature of 827°C. Calculated. This flow continues in zone 17 with the unreacted fuel/air mixture passing through holes 26. mixture to produce a gas mixture at a temperature of 440°C.

This gas mixture then passes through the catalyst body 15. The fuel passing through the combustion path of the catalyst body 15 assuming that 93% of the fuel/air mixture burns during passage through these combustion paths. is calculated that the gas entering the sleeve combustion zone 20 has a temperature of 905°C; The temperature of the methane-containing gas downstream of the catalyst body 15 is practically instantaneous, homogeneous (i.e. , gas phase) is sufficiently hot to maintain combustion, but the generation within the passage of the catalyst body 15 is The fire delay time is the main value within such passages with respect to the residence time within such passages. The temperature is such that the ignition delay time does not result in qualitatively homogeneous combustion.

The air (constituting 43% of the total amount of air supplied to the casing inlet zone 11) is It passes through pass 22 and is essentially unheated from its inlet temperature of 300°C.

Fuel is added to this air passing through the annular bypass 22 from an injector 24. If not, the hot gas flow generated in the sleeve combustion zone 20 is transferred to the casing exit zone. At 12, it is mixed with the air that has passed through the annular bypass 22 to a temperature of 950°C. produces a gas mixture of This air that has passed through the annular bypass 22 is injected into the injector. If fuel is added from 24, the hot gas mixture from sleeve combustion zone 20 When mixed with The temperature is high for a few minutes. Therefore, combustion occurs and the fuel additive from the injector 24 Depending on the amount added, gas mixtures with temperatures of over 950° C. are obtained.

Instead of providing a restriction 32, the annular bypass 22 is made narrower so that the casing inlet A word principle restricting the flow through the bypass to 43% of the total air volume supplied to zone 11. It will be understood.

In the above embodiment, the amount of fuel injected into the annular bypass 22 from the valve 25 is increased. It has been recognized that combustion can be changed from idling to full load by It will be done. However, during this modification, the catalytic combustion in the catalyst body does not change. catalyst temperature is maintained below about 950°C, so it is active at low temperatures, but at about 950°C Catalysts that lose their activity when exposed to temperatures exceeding This makes starting easier.

In a gas turbine, the hot gas from the casing outlet band 2 is supplied with, for example, steam or Add a large amount of ballast gas, such as air, and mix It will be appreciated that the temperature is adjusted before the material enters the turbine.

Translation submission form for supplementary text (Article 184-8 of the Patent Law)

Claims (10)

[Claims] 1. (a) A combustion passage having a plurality of through passages, some of which have a combustion catalyst on the passage wall. and at least a portion of the other portion does not include a catalyst and includes a bypass preparatory layer adjacent to the combustion path. a catalytic combustion unit that is a heat path; (b) an air space in the combustion path and the bypass preheating path; (c) means for supplying a first gas stream comprising air and fuel; a downstream afterburn zone; (d) means for supplying a second gas stream comprising air to said afterburn zone; and; (e) means for introducing a variable amount of fuel into the second gas stream upstream of the afterburn zone. A combustion device comprising stages. 2. The combustion unit includes a catalyst-containing combustion path and a non-catalytic bypass pre-assembly adjacent to said combustion path. at least two successive catalytic bodies each including a thermal path; The combustion device according to claim 1, further comprising a mixing zone. 3. The ratio of bypass preconditioning passages to catalyst-containing combustion passages for one catalyst body is different from that for other catalyst bodies. 3. The combustion device according to claim 2, wherein: are different. 4. In addition to the bypass preheating path of the catalyst body, between the catalyst body and the adjacent downstream catalyst body with other bypass means for supplying additional fuel/air mixture to the mixing zone of the The combustion device according to claim 2 or 3. 5. Claims 1 to 4, wherein each catalyst-containing combustion passage is surrounded by a non-catalytic bypass preheating passage. The combustion device according to any one of the above. 6. The upstream catalyst body includes two or more catalyst bodies having a through-catalyst-containing combustion path in series; The combustion device according to any one of claims 1 to 5, wherein the catalyst of the downstream catalyst body is different from the catalyst of the downstream catalyst body. 7. (a) A combustion passage having a plurality of through passages, some of which have a combustion catalyst on the passage wall. and at least a portion of the other portion does not include a catalyst and includes a bypass preparatory layer adjacent to the combustion path. Air and fuel are provided in the combustion path and the bypass preheating path of the catalytic combustion unit, which are heat paths. providing a first gas flow comprising a first gas flow, whereby combustion of the fuel occurs within the combustion path. heat is transferred through the passage wall to the adjacent bypass preheating path to The air and fuel passing through the preheating path are preheated, and the fuel passing through the bypass preheating path is preheated. Combustion is performed downstream of the combustion path and the bypass preheating path, and high temperature combustion has been completed. (b) adding a second gas comprising air to the high temperature combusted gas stream; (c) before adding said second gas stream to said hot combusted gas stream; and varying the amount of fuel added to the second gas stream. 8. The amount of air supplied to the combustion path and the bypass preheating path is constant, and the amount of air supplied to the combustion path and the bypass preheating path is constant. and the amount of fuel supplied to the bypass preheating path is equal to the amount of burned gas from the combustion path. so as to maintain a constant temperature of the mixture with unburned gas from the bypass preheating path. 8. The method of claim 7, wherein the method is controlled. 9. Compressing air and mixing a portion of this air with fuel to supply said fuel as a first gas stream. a heating path and the bypass preheating path, the remainder forming the second gas flow; 9. A method according to claim 7 or 8, wherein variable amounts of fuel are added to the two gas streams. 10. 10. The method according to claim 7, wherein the amount of air in the second gas flow is constant. Method.