JPH0132403B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalytic combustion device, and more particularly to a catalytic combustion device that can control combustion temperature.

In recent years, catalytic combustion devices that utilize catalytic reactions have been researched and developed with the aim of putting them into practical use. This enables high-load combustion by promoting or controlling the combustion of gas and liquid fuels through catalytic reactions, making equipment more compact, reducing air pollutants such as nitrogen oxides, and even improving combustion efficiency. Applications to boilers, gas turbine plants, etc. are being considered.

There are several problems in the research and development of such catalytic combustion devices, and among them, there is an urgent need to develop a combustion catalyst that has a particularly long life and is highly reliable. When designing a combustion catalyst, the key point is how to extract and control the heat generated by the combustion reaction, but in the case of catalysts using base materials with low heat transfer coefficients such as ceramics, heat transfer is mainly based on radiation, and an increase in the temperature of the gas and catalyst is unavoidable. Therefore, active components that evaporate and volatilize in high-temperature regions cannot be used, and expensive noble metals such as platinum must be used as catalyst components. Further, oxide catalysts such as nickel and chromium have been proposed in place of these noble metals, but their activity cannot be said to be sufficient.

From the above background, in plants that mainly utilize heat, such as boilers, if the heat generated by combustion reactions can be successfully extracted and the combustion temperature can be controlled, it will be possible to effectively utilize heat and produce vanadium, molybdenum, manganese, etc. It is also possible to use inexpensive and highly active ingredients such as, which is extremely advantageous industrially.

SUMMARY OF THE INVENTION An object of the present invention is to provide a catalytic combustion device that eliminates the drawbacks of the prior art described above and is capable of recovering heat and controlling reaction temperature.

In order to control the combustion temperature in catalytic combustion and effectively utilize the generated heat, the present invention separates the catalytic reactor into a heat exchange type catalyst section and a non-heat exchange type catalyst section, and the fuel in each catalyst section is By changing the combustion ratio, the amount of heat generated and the amount of heat recovered is controlled.

The present invention provides a catalytic combustion device having a catalytic reactor for burning a mixed gas containing a fuel and a combustion improver, wherein the catalytic reactor is a heat exchange type catalyst in which a catalyst component is attached to a metal structure having a heat exchange part. and a non-heat exchange type catalyst section in which a catalyst is attached to a structure having no heat exchange section.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a block diagram of a catalytic combustion apparatus showing one embodiment of the present invention. This device system includes a mixer 1 that mixes fuel and a combustion improver, and a heat exchange reactor 2 that combusts the fuel mixed in the mixer 1 and transfers the combustion heat to a medium in a heat exchanger.
and a non-heat exchange type combustion reactor 3 that burns the gas containing residual fuel that has exited the heat exchange type reactor 2;
It is comprised of a conventional heat exchanger 4 for recovering heat from the exhaust gas exiting the non-heat exchange type combustion reactor 3.

In the above configuration, after fuel and combustion improver (air) are introduced into the mixer 1 through lines 11 and 12 and mixed, the mixed gas is introduced into the heat exchange type catalytic reactor 2 through the line 13. The appropriate temperature of the introduced gas at this time is 200 to 400°C. As an example of the heat exchange type catalytic reactor 2 is shown in FIG. A medium such as water or steam is passed through it. In the reactor 2, fuel and air come into contact with a combustion catalyst, and a combustion reaction begins and progresses to generate combustion heat. A medium such as steam is introduced into the reactor 2 through a line 21, and a medium heated within the tubular heat transfer body 5 is taken out through a line 22. The reaction rate in the catalyst layer in the reactor 2 can be adjusted by controlling the amount of combustion improver, ie, oxygen, and the amount of cooling medium supplied. The reaction temperature at this time is 800°C or lower, preferably 600°C or lower.

On the other hand, in order to increase the plant efficiency, it is necessary to increase the gas temperature, but for this purpose, the residual fuel content in the gas discharged from line 23 is increased, and this gas is transferred to the non-heat exchanger in the subsequent stage. What is necessary is to guide it to the catalytic reactor 3 and combust it. As the non-heat exchange type catalyst, ceramic-based catalysts supporting catalytic metals such as vanadium, molybdenum, manganese, etc. in addition to ordinary platinum are suitable. The temperature of this part is 1300℃
The temperature below is preferably 1000°C or less. The heated combustion gas is led to the heat exchanger 4 through the line 31, and the recovered heat in this part is
Used for superheating steam, heating water and air, etc. Exhaust gas is discharged through line 41.

According to the above embodiment, by adjusting the amount of cooling medium and the amount of oxygen in the heat exchange type catalytic reactor, the combustion temperature thereof is controlled, and in connection therewith, the residual amount to be combusted in the non-heat exchange type catalytic reactor is By controlling the amount of fuel, the temperature of the combustion exhaust gas can be maintained at an appropriate value.

In the present invention, various forms of the heat exchange type catalyst structure can be considered, such as a finned tubular structure as shown in FIG. 2, and a honeycomb structure. Further, as the non-heat exchange type catalyst structure, known ones such as a parallel flow type catalyst structure and a packed type catalyst structure can be used. Ceramic materials that can withstand high-temperature reactions are suitable as the material.

As described above, according to the present invention, it is possible to control the reaction heat in the catalytic combustion reaction, recover the heat, and finally generate desired high-temperature combustion gas, thereby improving plant efficiency.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the catalytic combustion apparatus of the present invention, and FIG. 2 is a sectional view showing an example of a heat exchange type catalyst structure used in the present invention. 1...Mixer, 2...Heat exchange type catalytic reactor, 3
...Non-heat exchange type catalytic reactor, 4...Heat exchanger, 1
1... Fuel line, 12... Combustion aid line, 21
...Heating medium introduction line.

Claims (1)

[Claims] 1. In a catalytic combustion device having a catalytic reactor for combusting a mixed gas containing a fuel and a combustion improver, the catalytic reactor is a heat exchanger having a catalytic component attached to a metal structure having a heat exchange part. A catalytic combustion device characterized by having an exchange type catalyst section and a non-heat exchange type catalyst section in which a catalyst is attached to a structure having no heat exchange section in sequence in the gas flow direction. 2. The catalytic combustion device according to claim 1, wherein the structure having no heat exchange portion is made of ceramics. 3. A catalytic combustion device according to claim 1 or 2, wherein the metal structure has a tube structure, and the heat transfer medium is passed inside or outside the tube. 4. A catalytic combustion device according to claim 1 or 2, wherein the metal structure has heat transfer fins, and the fins are coated with a catalyst component.