JPH05346207A - Catalytic combustion device - Google Patents

Abstract

PURPOSE:To improve the property of waste gas by eliminating generation of NOx when compressed air or a mixture is preheated, and simplify fuel control to prevent deterioration and damage to catalyst in a catalytic combustion unit. CONSTITUTION:There are provided a fuel mixing unit 42 for mixing compressed air and fuel, a catalytic combustion unit 43 for causing the mixture to burn by catalytic reaction, a preheater 45 for heating the compressed air, an ECU 50 which controls electric power to the preheater based on a parameter representing an engine operation conditions so that inlet temperature of the unit 43 becomes a predetermined temperature, and a driver 51. Since the compressed air is heated (preheated) by the preheater, NOx is not generated during the preheating. Further, the inlet temperature of the catalytic combustion unit is stabilized approximately at a predetermined temperature, in which said temperature is prevented from becoming too high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic combustor used in a gas turbine engine or the like.

[0002]

2. Description of the Related Art Conventionally, as a catalytic combustor, for example, compressed air from a compressor is heated by a preburner, the heated compressed air and fuel are mixed, and the mixture is passed through a catalytic combustion section to carry out a catalytic reaction. It is known that the fuel is burned by the method described in JP-A-63-306303 and JP-A-2-85611.

[0003]

However, in the above-mentioned prior art, since the compressed air is heated by the preburner which burns by the flame, a large amount of NOx is generated by the combustion in this preburner and the exhaust gas characteristics deteriorate. There was a problem that it would end up.

Further, in the above-mentioned prior art, in addition to controlling the fuel supplied to the fuel mixing section for combustion in the catalytic combustion section, the fuel supplied to this burner for combustion in the preburner is controlled. Since it is necessary, fuel control becomes complicated. Furthermore, if the amount of fuel supplied to the preburner is too large, not only is the fuel wasted wastefully, but the inlet temperature of the catalytic combustion section becomes too high, and as a result, the catalyst in the catalytic combustion section becomes unusable. There was a problem that it deteriorates and is damaged, and when used in a gas turbine engine, the turbine inlet temperature becomes too high, the output becomes unstable, and the turbine is damaged. ..

The present invention has been made by paying attention to such a conventional problem, and aims at improving exhaust gas characteristics by eliminating generation of NOx at the time of preheating compressed air or a mixture, thereby simplifying fuel control. It is an object of the present invention to provide a catalyst combustor which prevents deterioration and damage of the catalyst in the catalyst combustion section.

[0006]

In order to achieve the above object, the present invention burns a fuel mixing section in which compressed air from a compressor is mixed with fuel and a mixture of compressed air and fuel by a catalytic reaction. In a catalytic combustor provided with a catalytic combustion unit for, and preheating means for heating the compressed air or the mixture,
A preheating heater as the preheating means, and a control means for controlling an energization amount to the preheating heater based on a parameter representing an engine operating state so that an inlet temperature of the catalyst combustion section becomes a predetermined temperature. (Claim 1).

In order to achieve the above object, the present invention provides a fuel mixing section in which compressed air from a compressor and fuel are mixed, and a catalytic combustion section in which a mixture of compressed air and fuel is burned in a catalytic reaction. In a catalytic combustor comprising a preheating means for heating the compressed air or the mixture, and a heat exchanger for heating the compressed air on the upstream side of the preheating means by the heat recovered from the exhaust gas, as the preheating means, It is provided with a preheat heater and a control means for controlling the amount of electricity supplied to the preheat heater according to the outlet air temperature of the heat exchanger (claim 2).

[0008]

In the catalytic combustor according to the first aspect, the compressed air or the mixture is heated (preheated) by the preheater, so that NOx is not generated during this preheat. Moreover, since the amount of electricity supplied to the preheater is controlled by the control means so that the inlet temperature of the catalytic combustion portion becomes a predetermined temperature, the inlet temperature of the catalytic combustion portion is stable near the predetermined temperature and is not too high. Absent.

Also in the catalytic combustor according to the second aspect, the compressed air or the mixture is preheated by the preheater, so that NOx is not generated during this preheat. Moreover, since the amount of electricity supplied to the preheater is controlled by the control means according to the outlet temperature of the heat exchanger, the inlet temperature of the catalytic combustion section is stable and does not become too high.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

In the description of each embodiment, the same parts are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 1 is a schematic diagram showing a gas turbine engine using a catalytic combustor according to a first embodiment of the present invention.
FIG. 2 is a vertical cross-sectional view showing this gas turbine engine.

As shown in FIG. 2, the gas turbine engine includes a main body housing 1, a turbine 2 having a turbine shaft 2a, and a centrifugal compressor 3 having a compressor rotor 3a rotating integrally with the turbine shaft 2a. And catalytic combustor 4
And an output shaft 5 connected to the turbine shaft 2a.

Combustion air that has passed through an air cleaner (not shown) is introduced into the duct 3b of the compressor 3, and the combustion air is compressed by the compressor rotor 3a that rotates integrally with the turbine shaft 2a. It is designed to be discharged.

An air passage 1a is formed on the inner wall of the main body casing 1 to guide the compressed air compressed by the compressor 3 to the catalytic combustor 4. This air passage 1a communicates with an air passage 4a formed on the outer peripheral portion of the catalytic combustor 4, and compressed air from the compressor 3 is introduced into the air passage 4a of the catalytic combustor 4 via the air passage 1a. It is supposed to be done.

An exhaust duct 6 is provided in the main body housing 1 for discharging the combustion gas (exhaust gas) that has passed through the turbine rotor 2b of the turbine 2 to the outside. The combustion gas from the catalytic combustor 4 is exhausted from the exhaust duct 6
The nozzle 2c of the turbine 2 passes through the space 1b around the nozzle 2c. The nozzle 2c has a variable stator vane 2
d is provided, and the turbine rotor 2b rotates by receiving the kinetic energy of the combustion gas that has passed through the stationary blade 2d and the nozzle 2c, so that the turbine shaft 2a thereof rotates.

At the downstream end of the exhaust duct 6, an oxidation / reduction catalyst 7 for purifying combustion gas emitted from the turbine 2 is provided.

The catalytic combustor 4 includes a cylindrical housing 40 fixed to the main body housing 1 and the housing 4
0, and has an inner cylinder 41 fixed inside the main body housing 1. A fuel mixing section 42 is provided inside the inner cylinder 41 on the upstream side, and a catalytic combustion section 43 including a catalyst layer is provided inside the inner cylinder 41 on the downstream side.

At the center of the upstream end of the inner cylinder 41, the fuel mixing section 42 is filled with fuel that is pressure-fed through a fuel pipe (not shown).
A fuel nozzle 44 for injecting is installed. Also,
An air introduction hole 41 a for introducing compressed air from the compressor 3 into the fuel mixing section 42 is provided at a plurality of locations in the conical portion formed at the upstream end of the inner cylinder 41.

Further, the catalytic combustor 43 has a preheating heater 45 provided in the air passage 4a at a position upstream of the air introducing hole 41a. This preheater 45
An electronic control unit (hereinafter referred to as an ECU) 50 and a driver 51 are provided as control means for controlling the amount of electricity supplied to the device.
And are provided.

As shown in FIGS. 1 and 2, in the gas turbine engine, a temperature sensor 61 and a pressure sensor 6 for detecting the outlet side temperature T1 and the outlet side pressure P1 of the compressor 3, respectively.
2 and the rotation speed of the turbine shaft 2a (the rotation speed of the compressor 3) N
The rotation speed sensor 63 for detecting e and the outlet side air temperature of the preheater 45 (this outlet side air temperature is
Since the temperature of the mixture of the compressed air and the fuel flowing into the chamber is substantially equal to the temperature of the mixture, a temperature sensor 64 for detecting T2 (referred to as the inlet temperature of the catalytic combustion portion 43) is provided in the following description. The temperature sensor 64 may be provided on the inlet side of the catalytic combustion unit 43 to directly detect the inlet temperature T2 of the catalytic combustion unit 43.

As shown in FIG. 1, the ECU 50 has an input circuit 50a having a function of converting an analog value of an input signal from each of the sensors 61 to 64 into a digital signal value, and a central processing arithmetic circuit. 50b (hereinafter referred to as CPU), a ROM storing various calculation programs executed by the CPU 50b, and an R storing operation results
The storage means 50c made of AM and the output circuit 50d are provided.

The ECU 50 determines that the inlet temperature T2 of the catalytic combustion section 43 (the outlet air temperature of the preheater 45) is a predetermined temperature TA.
(At the optimum combustion temperature in the catalytic combustion unit 43, for example, TA =
600 degrees), the energization amount to the preheat heater 45 is controlled on the basis of parameters indicating the operating state of the engine, for example, the rotation speed Ne, the outlet side temperature T1, and the outlet side pressure P1.

The operation of the first embodiment having the above construction will be described below with reference to FIG.

When a cell motor switch (not shown) is turned on to start the gas turbine engine, a self starter motor (not shown) is activated to start rotating the turbine shaft 2a and the compressor rotor 3a of the compressor 3. .. As a result, the combustion air is compressed by the compressor 3,
The compressed air passes through the passages 1a and 4a and the preheater 45
And is heated (preheated) to the fuel mixing section 42 from the air introduction hole 41a of the inner cylinder 41.
Will be introduced in. The compressed air and the fuel injected from the fuel nozzle 44 are mixed in the fuel mixing section 42, the mixture is combusted in the catalytic combustion section 43 by a catalytic reaction, and the combustion gas passes through the space 1b to the nozzle of the turbine 2. When the turbine rotor 2b rotates by receiving the kinetic energy of the combustion gas that has entered the 2c and passed through the variable vane 2d and the nozzle 2c, the turbine shaft 2a thereof rotates. Thereby, the driving force from the output shaft 5 to the load is obtained. Then, the combustion gas emitted from the turbine 2 is guided to the oxidation / reduction catalyst 7 through the inside of the exhaust duct 6, purified by the catalyst 7 and discharged to the outside.

When the operation of the gas turbine engine is started in this manner, the ECU 50 executes the control processing of the heater energization amount shown in FIG. 3 every predetermined time.

In this control process, in step 301, the engine speed N, which is a parameter representing the operating state of the engine, is set.
e, the outlet side temperature T1, and the outlet side pressure P1 are read, and in the next step 302, the inlet temperature (outlet side air temperature of the preheat heater 45) T2 of the catalytic combustion unit 43 detected by the temperature sensor 64 is read. After the execution of this step 302, the routine proceeds to the next step 303, where the rotation speed Ne and the outlet side pressure P1
From this, the air flow rate Q of the compressed air from the compressor 3 is calculated.

After that, the routine proceeds to step 304, where it is judged whether or not the inlet temperature T2 is lower than the predetermined temperature TA (for example, 600 degrees). When this determination result is YES,
That is, when T2 is lower than TA, the routine proceeds to step 305, where the air flow rate Q and its temperature (the outlet side temperature) T1.
Based on the above, the preheating heater 45 shown in FIG.
Determine the amount of increase in the amount of electricity supplied to. After this determination, the process proceeds to the next step 306, and the energization amount to the preheating heater 45 is increased by the increase amount determined in step 305. As a result, the inlet temperature T2 of the catalytic combustor 43 rises according to the temperature rise characteristic of FIG. After the execution of step 306, the process returns to step 301.

If the decision result in the step 304 is NO, the process advances to a step 307 to decide whether or not T2 = TA. When the result of this determination is YES, the routine proceeds to step 308, the current energization amount to the preheat heater 45 is maintained, and the routine returns to step 301.

On the other hand, the judgment result of step 307 is N
When it becomes O, that is, when T2 becomes equal to or more than TA, the routine proceeds to step 309, where the temperature rising characteristic table of the preheat heater shown in FIG. 4 is searched based on the air flow rate Q and its temperature (the outlet side temperature) T1. Thus, the amount of decrease in the amount of electricity supplied to the preheater heater 45 is determined. After this determination, the process proceeds to the next step 310, and the energization amount to the preheat heater 45 is reduced by the reduction amount determined in step 309. As a result, the inlet temperature T2 of the catalytic combustor 43 is lowered according to the temperature rise characteristic of FIG.
After the execution of step 310, the process returns to step 301.

As described above, according to the first embodiment, the compressed air from the compressor 3 is heated by the preheater 45 (preheat).
Therefore, NOx is not generated during this preheating. Therefore, the exhaust gas characteristics of the exhaust gas discharged through the exhaust duct 6 and the oxidation / reduction catalyst 7 are improved. Moreover,
By controlling the amount of electricity supplied to the preheating heater 45 as described above, the inlet temperature T2 of the catalytic combustion unit 43 is stabilized near the predetermined temperature TA, and the inlet temperature T2 does not become too high. Therefore, control of the fuel injected into the fuel mixing section 42 is simplified, and deterioration and damage of the catalytic combustion section 43 are prevented. Further, since the preheater 45 is used in place of the preburner used as the preheating means in the above-mentioned conventional technique, only the fuel supplied to the fuel mixing section 42 needs to be controlled. Therefore, fuel control is also simple in this respect. become.

In the first embodiment, the compressed air from the compressor 3 is heated by the preheat heater 45. However, the mixture of compressed air and fuel mixed in the fuel mixing section 42 is preheated by the preheat heater. The heating may be performed at 45.

Further, in the first embodiment, the inlet temperature of the catalytic combustion section 43 (air temperature on the outlet side of the preheat heater 45).
The amount of electricity supplied to the preheater 45 may be feedback-controlled so that T2 becomes a predetermined temperature.

Next, a second embodiment of the present invention will be described with reference to FIGS.

In the second embodiment, a heat storage type heat exchanger 70 is provided in the gas turbine engine of the first embodiment. That is, the heat exchanger 70 recovers heat from the combustion gas (exhaust gas) emitted from the turbine 2 and heats the compressed air from the compressor 3 with this heat.
In the second embodiment, a temperature sensor 65 for detecting the outlet air temperature T3 of the heat exchanger 70 is provided.

In the second embodiment, the ECU 50 preheats the outlet air temperature T3 detected by the temperature sensor 65 to a predetermined temperature TA (for example, 600 degrees), that is, preheats in accordance with the outlet air temperature T3. It is configured to control the amount of electricity supplied to the heater 45.

In the second embodiment, when the operation of the gas turbine engine is started, the heater energization amount control process shown in FIG. 6 is executed at regular time intervals.

In this control process, in step 601, the outlet air temperature T3 of the heat exchanger 70 detected by the temperature sensor 65 is read. Next, in step 602,
It is determined whether T3 is lower than the predetermined temperature TA. When this determination result is YES, that is, when T3 is lower than the predetermined temperature TA, the routine proceeds to step 603, where the amount of electricity supplied to the preheat heater 45 is increased. After execution of step 603, the process returns to step 601.

When the decision result in the step 602 is NO, the routine proceeds to a step 604, and it is decided whether or not T3 = TA. When this determination result is YES, step 605
Then, the current amount of electricity supplied to the preheat heater 45 is maintained, and the process returns to step 601.

On the other hand, the judgment result of the step 604 is N
When it becomes O, that is, when T3 becomes TA or more, the routine proceeds to step 606, where the energization amount to the preheat heater 45 is reduced or the energization is stopped. After execution of step 606, the process returns to step 601.

Thus, also in the second embodiment,
Since the compressed air from the compressor 3 is heated (preheated) by the preheater 45, NOx is not generated during this preheat and the exhaust gas characteristics are improved. Moreover, by controlling the amount of electricity supplied to the preheater 45 as described above, the inlet temperature T2 of the catalytic combustion section 43 is stabilized, and the inlet temperature T2 does not become too high. Therefore, control of the fuel injected into the fuel mixing section 42 is simplified, and deterioration and damage of the catalytic combustion section 43 are prevented.

[0042]

As described above in detail, according to the catalytic combustor of the present invention (Claim 1), the fuel mixing section in which the compressed air from the compressor and the fuel are mixed, the compressed air and the fuel are mixed. In a catalytic combustor provided with a catalytic combustion unit for combusting the mixture by a catalytic reaction, and a preheating unit for heating the compressed air or the mixture, a preheating heater as the preheating unit,
With a configuration including control means for controlling the amount of electricity supplied to the preheater based on a parameter indicating the engine operating state so that the inlet temperature of the catalytic combustion part becomes a predetermined temperature, compressed air or a mixture is supplied by the preheater. Heating (preheat)
Therefore, NOx is not generated during this preheating. Moreover,
Since the amount of electricity supplied to the preheating heater is controlled by the control means so that the inlet temperature of the catalytic combustion portion becomes the predetermined temperature, the inlet temperature of the catalytic combustion portion is stable around the predetermined temperature and does not become too high. Therefore, the generation of NOx at the time of preheating the compressed air or the mixture can be eliminated to improve the exhaust gas characteristics, the fuel control can be simplified, and the deterioration and damage of the catalyst in the catalyst combustion section can be prevented. Further, since the inlet temperature does not become too high, when used in a gas turbine engine, the turbine inlet temperature does not become too high, the output is stable, and the turbine is not damaged.

According to the catalytic combustor of the present invention (Claim 2), the fuel mixing section in which the compressed air from the compressor is mixed with the fuel, and the catalyst for burning the mixture of the compressed air and the fuel by the catalytic reaction. A catalyst combustor comprising a combustion section, a preheating means for heating the compressed air or the mixture, and a heat exchanger for heating the compressed air on the upstream side of the preheating means by the heat recovered from the exhaust gas, wherein the preheating means And a control means for controlling the amount of electricity supplied to the preheater according to the outlet air temperature of the heat exchanger,
Since the preheating heater preheats the compressed air or the mixture, NOx is not generated during this preheating. Moreover, since the amount of electricity supplied to the preheater is controlled by the control means in accordance with the outlet temperature of the heat exchanger, the inlet temperature of the catalytic combustion section is stable and does not become too high. Therefore, the generation of NOx at the time of preheating the compressed air or the mixture can be eliminated to improve the exhaust gas characteristics, the fuel control can be simplified, and the deterioration and damage of the catalyst in the catalyst combustion part can be prevented. Further, when used in a gas turbine engine, the output is stable and the turbine is not damaged for the same reason as above.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a gas turbine engine using a catalytic combustor according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing the gas turbine engine of FIG.

FIG. 3 is a flowchart showing a control process of a heater energization amount in the first embodiment.

FIG. 4 is a graph showing a temperature rising characteristic of a preheating heater.

FIG. 5 is a schematic configuration diagram showing a gas turbine engine using a catalytic combustor according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing a heater energization amount control process in the second embodiment.

[Explanation of symbols]

 3 Compressor 4 Catalytic Combustor 42 Fuel Mixing Section 43 Catalytic Combustion Section 45 Preheater 50 ECU (Control Means) 51 Driver (Control Means)

Claims (2)

[Claims] 1. A fuel mixing section in which compressed air from a compressor and fuel are mixed, a catalytic combustion section in which a mixture of compressed air and fuel is burned by a catalytic reaction, and preheating for heating the compressed air or the mixture. In a catalytic combustor with means,
A preheating heater as the preheating means, and a control means for controlling an energization amount to the preheating heater on the basis of a parameter representing an engine operating state so that an inlet temperature of the catalyst combustion section becomes a predetermined temperature. A catalytic combustor characterized by. 2. A fuel mixing section for mixing compressed air and fuel from a compressor, a catalytic combustion section for burning a mixture of compressed air and fuel in a catalytic reaction, and preheating for heating the compressed air or the mixture. Means and a heat exchanger for heating the compressed air with the heat recovered from the exhaust gas on the upstream side of the preheating means, a preheating heater as the preheating means, and an outlet air temperature of the heat exchanger. And a control means for controlling the amount of electricity supplied to the preheater according to the above.