JPS59146910A - Endothermic gas converter - Google Patents

Abstract

PURPOSE:To prevent local overheating and to obtain a uniform temp. distribution in a catalytic reaction vessel by enlarging gradually the sectional area of the gas flow passage in the vessel from the suction side to delivery side. CONSTITUTION:In a catalytic reaction vessel 7 wherein the sectional area of the gas flow passage is enlarged gradually from the suction side to delivery side, Co catalyst 6 having low-temp. activity is packed. The vessel 7 is heated by supplying an electric current to a heating furnace 4 from an electric source 5. Gaseous hydrocarbon and air are supplied into the vessel 7 through flowmeters 1, and the hydrocarbon is converted into an endothermic gas. In this way, the temp. in the vessel is kept at a comparatively low temp. and the durability of the catalytic reaction vessel and the Co catalyst can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endothermic gas transformation device for transforming endothermic gas used in heat treatment such as hardening and tempering of steel parts or carburizing and quenching.

Endothermic gas used in heat treatments such as quenching, tempering, and carburizing of steel parts is conventionally generated by an endothermic gas conversion device called an endothermic gas generator, as shown in Figure 1. .

This endothermic gas generating furnace is a retort 2 filled with a nickel catalyst 3 and heated and maintained at 1000 to 1100°C in a heating furnace 4. Hydrocarbon gas, such as methane, propane, or butane gas, and air Supplying a mixed gas, Co,
Main components are H2 and N2, with trace amounts of methane, CO2, and H2
It transforms an endothermic gas containing O.

The reaction of partially oxidizing this hydrocarbon gas with air is
Because it is an endothermic reaction, it is called an endothermic gas.

In this endothermic gas conversion method using an endothermic gas generating furnace, a heating furnace 4 is used to heat and maintain the retort 2 at a high temperature.
The disadvantage is that the equipment cost is excessive.

In addition, in an endothermic gas generating furnace, the heater of the heating furnace 4 is frequently disconnected, and the reactivity of the nickel catalyst 3 is significantly deteriorated.
When the reactivity of the nickel catalyst 3 deteriorates, there is a disadvantage that the maintenance cost required for operations to restore the reactivity of the endothermic gas generating furnace, replacement of the nickel catalyst 3, etc. increases.

In view of these shortcomings of conventional endothermic gas generating furnaces, the inventors have developed a method that can be used at lower temperatures (850 to 90°C) compared to conventional nickel catalysts.
invented a cobalt catalyst that is active at a temperature of 50°C), filled a catalytic reaction vessel with the cobalt catalyst that is active at a low temperature, and
A mixed gas of hydrocarbon (CH4, C, H8, C4H, etc.) gas and air is supplied to a catalytic reaction vessel heated and maintained at 0 to 950 °C, and the main components are CC, H2, N2, We proposed a method for converting endothermic gases containing trace amounts of CH4, cC2, H20, and C (Japanese Patent Application No. 134952/1982).

According to this endothermic gas conversion method, taking butane as an example, it is converted into an endothermic gas through the reaction C4HIO+ 202 → 4CO+5H2.

At this time, depending on the mixing ratio of butane and air, some CH
4, CO2, H20, etc. are generated.

By the way, in this endothermic gas conversion method, the reaction between hydrocarbon gas and air consists of an exothermic reaction and an endothermic reaction, so at the active site of the exothermic reaction in the catalytic reaction vessel,
The disadvantage is that the temperature inside the container increases significantly, which accelerates the deterioration of the catalyst reaction container and the catalyst itself, resulting in high maintenance costs.

Furthermore, to explain this endothermic gas conversion method using a specific example,
In Figure 2, 0.86β/min of butane and 8.6
A mixed gas consisting of n/min air is mixed with 93
100 CC cobalt catalyst heated and held at 0°C6
When fed to the catalytic reaction vessel 7 filled with 15j! /m
The endothermic gas of in is transformed.

At that time, as shown in FIG.
There is a disadvantage that the temperature rises to about .degree. C. and the durability of the catalyst reaction vessel 7 and the cobalt catalyst 6 itself is significantly deteriorated.

On the other hand, near the center of the catalytic reaction vessel 7 (section B), the temperature inside the vessel decreases slightly due to the endothermic reaction, but this is not enough to affect the gas shift reaction.

By improving the shape of the catalyst reaction vessel, the present invention prevents partial overheating within the catalyst reaction vessel, equalizes the temperature distribution throughout the catalyst reaction vessel, and improves the durability of the catalyst reaction vessel and the catalyst itself. The purpose of the present invention is to provide an endothermic gas shift device.

According to the present invention, such a purpose is achieved by feeding a mixed gas of hydrocarbon gas and air into a catalytic reaction vessel filled with a cobalt catalyst that is active at low temperature and set at the reaction temperature of the cobalt catalyst to absorb heat. An endothermic gas shift device for converting type gas, wherein the cross-sectional area of the gas flow path of the catalytic reaction vessel is directed from the intake side of the mixed gas of hydrocarbon gas and air toward the output side of the endothermic gas that has been converted, This is achieved by a thermothermal gas shift device characterized by being formed so as to gradually expand.

The present invention will be described in detail below based on the accompanying drawings.

FIG. 4 shows an endothermic gas shift apparatus according to the present invention.

The catalytic reaction vessel was changed from the cylindrical catalytic reaction vessel 7 shown in Fig. 2 to a cylindrical platform-shaped catalytic reaction vessel with a 3.3゜ taper while keeping the volume and length constant. The gas flow rate at the gas-air mixed gas inlet was approximately four times the gas flow rate at the modified endothermic gas outlet.

As a result, as shown in FIG. 5, the temperature distribution inside the catalytic reaction vessel 7' becomes uniform, and even in the exothermic reaction section (A section) near the mixed gas feed port, the exothermic reaction is dispersed over a wide area. The temperature inside the container does not rise partially.

In this embodiment, like the conventional device (FIG. 2), 0
．． 861! A mixed gas consisting of butane at ,/min and air at 3.5 A/min was heated and held at 930°C,
100 CC of cobalt catalyst 6 was fed to the catalytic reaction vessel 7', and 1511! /min of endothermic gas was converted.

At this time, the temperature distribution inside the catalytic reaction vessel 7' can suppress the maximum temperature inside the vessel to 960°C as shown in Fig. 5, improving the durability of the catalytic reaction vessel 7' and the cobalt catalyst 6 itself. We were able to.

As is clear from the above, according to the endothermic gas shift device according to the present invention, by improving the shape of the catalytic reaction vessel, partial overheating within the vessel can be prevented, and the temperature distribution throughout the catalytic reaction vessel can be made uniform. This has the advantage of improving the durability of the catalytic reaction vessel and the cobalt catalyst itself.

[Brief explanation of drawings]

Fig. 1 shows a conventional endothermic gas generator, Fig. 2 shows an endothermic gas conversion device proposed in Japanese Patent Application No. 57-13J952, and Fig. 3 shows the catalytic reaction vessel shown in Fig. 2. FIG. 4 is a diagram showing the endothermic gas shift apparatus according to the present invention, and FIG. 5 is a diagram showing the temperature distribution inside the catalytic reaction vessel shown in FIG. 4. 1---One flow meter 2---Retort 3---=-Nickel catalyst 4---1---Heating furnace 5---1 Power source 6------Cobalt catalyst 7.7' -1 Catalyst Reaction container A --- One exothermic reaction site B --- One exothermic reaction site Distributor: Toyoku Kuginogo Shikisha Co., Ltd.

Claims (1)

[Claims] (1) Endothermic gas that converts endothermic gas by feeding a mixed gas of hydrocarbon gas and air into a catalyst reaction vessel filled with a cobalt catalyst that is active at low temperatures and set at the reaction temperature of the cobalt catalyst. In the shift conversion device, the cross-sectional area of the gas flow path of the catalytic reaction vessel is formed so as to gradually expand from the intake side of the mixed gas of hydrocarbon gas and air toward the output side of the endothermic gas that has been converted. This is an endothermic gas shift equipment.