JPS61195215A - Catalytic burning device - Google Patents

Abstract

PURPOSE:To keep catalyst layers in the optimum temp. conditions and obtain long service lives by installing multistage catalyst layers in such a manner that each layer is made on the basis of the special temp. characteristic of its catalyst and suitable amount of fuel is supplied. CONSTITUTION:Amount of injected fuel 15 from a primary nozzle 16 is adjusted by a flow control valve 18 so as to fit the special temp. characteristic of a activated catalyst layer 13 at low temp. side and after fuel is mixed with air 11, the mixture at about 300 deg.C flows into the catalyst layer 13 and then flows out after oxidation reaction is promoted. Then, amount of fuel 15 from nozzle 17is adjusted by a flow control valve 19 so as to fit the special temp. characteristic of activated catalyst layer 14 and after the fuel is mixed with the mixture from the catalyst layer 13, the mixture at about 600 deg.C flows through a catalyst layer 14 and then flows out as high temp. fluid 20. Therefore, as each catalyst layer is kept in a fitted temp. condition, reliability of catalyst characteristic is maintained and a long service life of catalyst is also obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a catalytic combustion device that uses a catalyst to accelerate the oxidation reaction of fuel to obtain a high-temperature fluid.

<Prior Art> In recent years, so-called catalytic combustion devices have been widely used, which use catalysts to efficiently oxidize fuel to obtain a predetermined high-temperature fluid. As the structural concept of this catalytic combustion device is shown in FIG. 4, a catalyst layer 3 is provided in an intake passage 2 through which air 1 is sent, and fuel 4 is injected toward the catalyst layer 3 on the intake side of this catalyst layer 3. A fuel nozzle 5 is provided. The catalyst layer 3 is composed of a low-temperature side active catalyst 3a and a high-temperature side active catalyst 3b, and even if the mixed fluid of air 1 and fuel 4 passes through the catalyst layer 3, the temperature rises due to the progress of the oxidation reaction. The catalyst layer 3 is suitable for the reaction environment temperature of the mixed fluid. (See FIG. 5, which shows a graph showing the temperature distribution of the mixed fluid.) The characteristics of the low-temperature side active catalyst 3a are such that the permissible temperature is low in terms of durability.

In this catalytic combustion device, fuel 4 injected from a fuel nozzle 5 is mixed with air 1 and introduced into a catalyst layer 3, and the mixed fluid of fuel 4 and air 1 is oxidized by catalytic action in the catalyst layer 3. The high temperature fluid 6 is formed and flows out. In the catalyst layer 3, the temperature of the mixed fluid increases as the oxidation reaction progresses, but since the catalyst layer 3 is composed of a low-temperature side active catalyst 3a and a high-temperature side active catalyst 3b, the temperature of the mixed fluid increases gradually. An efficient oxidation reaction suitable for the fluid is promoted.

<Problems to be Solved by the Invention> However, in the above-mentioned catalytic combustion device, if the mixing ratio of the mixed fluid introduced into the catalyst layer 3 is uneven, the low-temperature side active catalyst is The reaction is locally promoted in 3a, causing a self-cutting combustion reaction, and the mixed fluid becomes a high-temperature fluid that is higher than the allowable temperature value of the low-temperature side active catalyst 3a. Furthermore, if the mixing ratio of the mixed fluid is inappropriate, excessive reaction will be promoted in the low-temperature side active catalyst 3a, and the mixed fluid will become an abnormally high-temperature fluid with a temperature higher than the allowable temperature value of the low-temperature side active catalyst 3a. As a result, the low-temperature side activated catalyst 3a reaches a high temperature exceeding the allowable temperature value, resulting in a loss of durability and a loss of the characteristic of being excellent in promoting reactions of low-temperature fluids.

The present invention was made to solve this problem.
To provide a catalytic combustion device in which a mixed fluid exceeding an allowable temperature value is not sent to the catalyst layer, thereby ensuring long-term reliability of catalyst characteristics and improving the durability and reliability of the catalytic combustion device. purpose.

<Means for Solving the Problems> The configuration of the present invention to achieve this object is a catalytic combustion device that promotes the oxidation reaction of fuel with a catalyst layer to obtain a high-temperature fluid. The present invention is characterized in that the catalyst layer is divided into multiple stages based on temperature characteristics, and each of the catalyst layers configured in multiple stages is provided with a fuel injection means.

<Operation> From the fuel injection means provided in each of the catalyst layers configured in multiple stages, fuel is sent in an amount that matches the temperature characteristics of each catalyst layer. Therefore, a good mixed fluid is always sent to the catalyst layer, thereby extending the life of the catalyst layer.

<Example> The first factor is the structural concept of a catalytic combustion device according to an embodiment of the present invention, FIG. 2 is a graph showing the temperature distribution of the mixed fluid in the catalytic combustion device shown in FIG. The figure shows a distribution representing the temperature characteristics of the catalyst layer.

An intake passage 12 through which air 11 is sent is provided with a low-temperature active catalyst layer 13 made of a noble metal catalyst such as palladium or platinum, and a high-temperature active catalyst layer 14 made of a transition metal catalyst such as chromium oxide or cobalt oxide. ing. The active catalyst layer 13 on the low temperature side has an active temperature of about 300"C to about 1000'C,
The heat resistant temperature is about 300'C to about 1000'C.

The active catalyst layer 14 on the high temperature side has an active temperature of about 00°C to about 1500°C, and a heat resistance temperature of about 600"C to about 1500°C.
It is. On the intake side of the low temperature side active catalyst layer 13, there is a primary nozzle 1-6 which is a fuel injection means for injecting an amount of fuel 15 matching the temperature characteristics of the low temperature side active catalyst layer 13 into the low temperature side active catalyst layer 13 side. A secondary nozzle is provided on the intake side of the high temperature side active catalyst layer 14 and is a fuel injection means for injecting an amount of fuel 15 that matches the temperature characteristics of the high temperature side active catalyst layer 14 to the high temperature side active catalyst layer 14 side. 17 are provided. 1 in the diagram
8.19 is a flow rate regulating valve.

In this example, the catalyst layer was divided into two stages, but
It is not limited to two stages, and the type of catalyst is not limited to those described above.

In this catalytic combustion device, the flow rate of the fuel 15 injected from the second nozzle 16 is adjusted by the flow rate adjustment valve 18 according to the temperature characteristics of the low-temperature side active catalyst layer 13, and the fuel 15 is injected from the second nozzle 16. The fuel 15 mixed with air 11 is introduced into the low temperature side active catalyst layer 13 as a mixed fluid at about 300°C. The mixed fluid at about 300°C is in the low-temperature side active catalyst layer 13.
The oxidation reaction is accelerated by the catalytic action, and the water becomes hot and flows out. The fuel 15 injected from the secondary nozzle 17 is supplied to the flow rate regulating valve 1 according to the temperature characteristics of the high temperature side active catalyst layer 14.
The flow rate is adjusted at 9, and the fuel 15 injected from this secondary nozzle 17 is mixed with the mixed fluid flowing out from the low-temperature side active catalyst layer 13, and the mixed fluid at about 600°C is delivered to the high-temperature side active catalyst layer 14. be introduced. The mixed fluid at about 600°C is catalytically oxidized in the active catalyst layer 14 on the high temperature side, and the mixed fluid becomes a high-temperature fluid 20 at about 1200°C and flows out.

Therefore, in this catalytic combustion device, fuel 15 whose flow rate is adjusted according to the temperature characteristics of each catalyst is sent to the low-temperature side active catalyst layer 13 and the high-temperature side active catalyst layer 14. In .14, the oxidation of the mixed fluid within the allowable temperature value can be promoted sequentially, so each catalyst layer 13.
A mixed fluid exceeding the permissible temperature value is not sent to 14.

<Effects of the Invention> The catalytic combustion device of the present invention has a catalyst layer divided into multiple stages based on the temperature characteristics of the catalyst, and each catalyst layer is provided with a fuel input means to supply the appropriate amount of fuel to each catalyst layer. As a result, the mixing ratio of fuel is always maintained at an appropriate level, ensuring maintenance of the catalyst layer, extending the life of the catalyst, and improving the durability and reliability of the catalytic combustion device. Become.

[Brief explanation of the drawing]

FIG. 1 is a structural conceptual diagram of a catalytic combustion device according to an embodiment of the present invention, and FIG. 2 is a graph showing the temperature distribution of the mixed fluid in the catalytic combustion device shown in FIG. 1. FIG. 4 is a schematic diagram of the structure of a conventional catalytic combustion device, and FIG. 5 is a graph showing the temperature distribution of the mixed fluid in the catalytic combustion device shown in FIG. 4. In the drawing, 11 is air, 13 is a low-temperature active catalyst layer, 14 is a high-temperature active catalyst layer, 15 is fuel, 16 is a primary nozzle, 17 is a secondary nozzle, 18.19 is a flow rate adjustment valve, and 20 is a high-temperature fluid. It is. Fig. 1m Fig. 2 Ant number 4 of the 47th figure Fig. 3

Claims (1)

[Claims] A catalytic combustion device that obtains high-temperature fluid by promoting the oxidation reaction of fuel with a catalyst layer, the catalyst layer is configured to be divided into multiple stages based on the temperature characteristics of the catalyst, and each of the catalyst layers configured in the multiple stages is A catalytic combustion device characterized by being provided with fuel input means.