JPH069973A - Catalytic combustion apparatus - Google Patents

Abstract

PURPOSE:To stabilize the ambient temperature of a duct for a fluid to be heated, thereby permitting a uniform and efficient reforming of the fluid. CONSTITUTION:A duct 2 for a fluid to be heated is installed in a fuel gas combustion chamber 1 and a catalyst 3 for catalytic combustion is arranged around the duct 2. Further, a temperature sensor 6 is equipped in the duct 2. The temperature detected by the sensor 6 is maintained at a given value by means of an arithmetic and control unit 7 provided to control the feed of the fuel gas to the chamber 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic combustion apparatus for burning a fuel such as natural gas in contact with a catalyst and utilizing the generated heat of oxidation for reforming a coal gas.

[0002]

2. Description of the Related Art Generally, it is known that the ignition temperature of fuel gas such as natural gas is much lower than the case of using no catalyst when the catalyst is used. Table 1 shows the relationship between the non-catalyst ignition temperature and the catalyst oxidation start temperature. As is clear from Table 1, the catalyst oxidation onset temperature is lower than the non-catalyst ignition temperature.
When formalin is used as the fuel gas, it can be oxidized at room temperature. For reference, each complete oxidation temperature (minimum temperature) is illustrated. This temperature can be set within a wide range by increasing the fuel gas supply amount.

[0003]

[Table 1]

FIG. 1 is a schematic vertical sectional view showing a conventional catalytic combustion apparatus. In the drawing, 1 is a combustion chamber, 2 is a flow pipe for a fluid to be heated, and 3 is a catalyst such as Pt formed in a honeycomb structure. Is shown. The combustion chamber 1 is formed in a cylindrical shape, the catalyst 3 is provided below the intermediate portion in the axial direction, and the flow pipe 2 for the fluid to be heated is provided above the catalyst 3.
Are disposed at a predetermined distance from each other. A fuel gas (mixed gas) supply pipe (not shown) is connected to the lower end of the combustion chamber 1, and an exhaust gas pipe (not shown) is connected to the upper end thereof.

Thus, in such a catalytic combustion apparatus, fuel gas is supplied from below the combustion chamber 1 in the direction indicated by the arrow, and is oxidized at a room temperature or in the course of preheated catalyst 3 to be oxidized. While heating the flow pipe 2 with heat, the fluid to be heated is caused to flow into the flow pipe 2 through the supply pipe 5, and the fluid to be heated is heated to a predetermined temperature to cause its reforming reaction. Has become.

Usually, such a catalytic combustion apparatus has the following features because it can burn fuel gas with a catalyst in a flameless state or in a state close to that. It is used. For example, in the platform reforming and reni-homing, which are catalytic reforming processes that transform gasoline into a structure with a high octane number, heat (450
Reforming is carried out by passing through the catalyst while applying pressure (~ 540 ° C) and pressure (10-50 atm).

[0007]

By the way, such a catalytic combustion apparatus is combined with a heat exchanger to recover the radiant heat from the catalyst surface or the heat of the high temperature gas after passing through the catalyst as energy for reforming. Used to do it. However, in such a conventional catalytic combustion apparatus, the catalyst 3 having a honeycomb structure is arranged below the combustion chamber, and the flow pipe 2 for heat exchange is arranged above the combustion chamber. Since and are vertically separated from each other, the heat generated by the oxidation reaction cannot be efficiently taken into the flow pipe 2, and in addition, the flow rate of the fuel gas is controlled according to the flow rate of the heated fluid in the flow pipe 2. In addition to the above, there was a problem that the temperature of the flow pipe 2 largely fluctuated and the reforming reaction efficiency was not stable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enhance the utilization efficiency of the heat of oxidation of fuel gas, and to achieve catalytic combustion capable of uniformly and stably heating a fluid to be heated. To provide the equipment.

[0009]

A catalytic combustion apparatus according to a first aspect of the present invention is a catalytic combustion apparatus in which a flow pipe for a fluid to be heated and a catalyst for catalytic combustion are provided in a combustion chamber, wherein the catalyst is It is characterized in that it is arranged around a flow tube so that the fuel gas supplied to the combustion chamber is burned while being in contact with the catalyst around the flow tube.

A catalyst combustion apparatus according to a second aspect of the present invention is a catalyst combustion apparatus in which a flow pipe for a fluid to be heated and a catalyst for catalytic combustion are provided in a combustion chamber, and a temperature sensor provided in the flow pipe, A control unit that controls the amount of fuel gas supplied to the combustion chamber so as to maintain the temperature detected by the temperature sensor within a predetermined range, and the catalyst is disposed around the flow pipe and is provided in the combustion chamber. It is characterized in that the supplied fuel gas is burned while being in contact with the catalyst around the flow pipe.

[0011]

In the first aspect of the present invention, since the catalyst is arranged around the flow pipe, the oxidation reaction of the fuel gas proceeds around the flow pipe of the fluid to be heated, and the stable and uniform heat of oxidation is obtained. Is obtained and high reforming reaction efficiency is obtained.

In the second aspect of the present invention, the temperature of the fluid to be heated is detected by a temperature sensor disposed in the flow pipe, and the control unit controls the fuel gas supply amount so that the temperature of the fluid to be heated becomes a predetermined temperature. It becomes possible to efficiently carry out the reforming reaction and the like by adjusting

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A catalytic combustion apparatus according to the present invention will be specifically described below with reference to the drawings. FIG. 2 is a schematic vertical sectional view of a catalytic combustion apparatus according to the present invention, in which 1 denotes a combustion chamber. The combustion chamber 1 is formed in a tubular shape extending upward and downward,
A flow pipe 2 for a fluid to be heated, for example, a liquid hydrocarbon such as naphtha, kerosene, crude oil, etc., is provided in an intermediate portion in the axial direction in such a manner as to penetrate through the catalyst 3 arranged therein.

A fuel gas supply pipe 4 with a control valve 4a interposed in the middle of the lower end of the combustion chamber 1 and an exhaust gas pipe (not shown) are connected to the upper end. The fuel gas supply pipe 4 is connected to the fuel tank and the air supply pipe, and supplies air and fuel gas in a mixed state. Combustible gases such as natural gas and LPG are used alone or as a mixed gas as the fuel gas. Of course, liquid fuel may be used if necessary. The catalyst 3 is mainly Pt.
However, other substances may be used.

FIG. 3 is an enlarged cross-sectional view showing the relationship between the flow pipe 2 and the catalyst 3. The catalyst 3 has a honeycomb structure in which a large number of through holes 3a are formed in a cylindrical body in parallel with the axial direction. It is installed in the combustion chamber 1 with the through hole 3a oriented parallel to the axial direction of the combustion chamber 1. Further, the catalyst 3 is provided with a plurality of pipes 2a forming the flow pipe 2 in a direction orthogonal to the axis of the catalyst, and both ends of each pipe 2a have a large diameter. The heating fluid supply pipe 5 is joined and connected.
Then, as shown in FIG. 2, one or a plurality of tubes located near the center of the tube 2a are located from one end thereof to the substantially central part of the tube 2a and the substantially central part of the combustion chamber 1. The temperature sensor 6 is inserted and fixed.

Reference numeral 7 is an arithmetic and control unit composed of a microcomputer or the like, and the detected temperature detected by the temperature sensor 6 inserted in the tube 2a is taken into it. The arithmetic control unit 7 compares the preset reference value with the temperature value of the temperature sensor 6, and when the temperature difference between the two exceeds an allowable value, the control valve 4a is opened / closed so that the temperature difference is within the allowable range. It is designed to be controlled.

Thus, in the catalytic combustion apparatus according to the present invention as described above, the fuel gas is supplied from below the combustion chamber 1 through the fuel gas supply pipe 4, and the inside of the catalyst 3 having a honeycomb structure at room temperature or preheated. The flow tube 2 is oxidized by flowing it, and the flow tube 2 is heated by the heat of oxidation. The naphtha, kerosene oil, crude oil, etc. flowing through the flow pipe 2 are heated and reformed into ethylene, propylene, olefin, etc. The exhaust gas is discharged from the upper part of the combustion chamber 1 through the exhaust gas pipe.

[0018]

As described above, in the apparatus of the first aspect of the present invention, not only the volumetric combustion rate is high and the furnace volume can be reduced, but also the catalyst for contact combustion around the flow pipe of the fluid to be heated is used. The present invention has excellent effects such that the utilization efficiency of the heat of oxidation reaction is improved and an efficient reforming reaction can be generated under a stable temperature.

In the apparatus of the second aspect of the present invention, a temperature sensor is provided in the flow pipe of the fluid to be heated, and the temperature detected by the temperature sensor, in other words, the temperature of the fluid to be heated is within a predetermined range. Since the fuel supply amount is controlled as described above, there is an excellent effect that an efficient reforming reaction can be obtained regardless of the conditions such as the material to be heated, the temperature and the flow rate.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a conventional device.

FIG. 2 is a schematic diagram of a catalytic combustion device according to the present invention.

FIG. 3 is an enlarged perspective view of a catalyst used in the catalytic combustion apparatus according to the present invention.

[Explanation of symbols]

 1 Combustion Chamber 2 Flow Pipe 3 Catalyst 4 Fuel Gas Supply Pipe 6 Temperature Sensor 7 Calculation Control Unit

Claims (2)

[Claims] 1. A catalytic combustion apparatus comprising a flow pipe for heating a fluid to be heated and a catalyst for catalytic combustion provided in the combustion chamber, wherein the catalyst is arranged around the flow pipe and is supplied to the combustion chamber. A catalytic combustion device characterized in that fuel gas is burned while being in contact with a catalyst around the flow pipe. 2. In a catalytic combustion device having a flow pipe for heating a fluid to be heated and a catalyst for catalytic combustion provided in a combustion chamber, a temperature sensor provided in the flow pipe and a temperature detected by the temperature sensor within a predetermined range. A control unit that controls the amount of fuel gas supplied to the combustion chamber so as to maintain the catalyst, and the catalyst is disposed around the flow pipe, and the fuel gas supplied to the combustion chamber is supplied to the flow pipe. A catalytic combustion device characterized by being burned while being in contact with a surrounding catalyst.