JPS6081002A - Endothermic gas conversion process and its apparatus - Google Patents

Abstract

PURPOSE:To suppress the formation of soot and to convert efficiently an endothermic gas by specifying the supply method of gaseous hydrocarbon in supplying a mixed gas of air and hydrocarbon into a retort which is packed with a catalyst and kept at high temps. CONSTITUTION:The endothermic gas converter consists of a flowmeter 4 of gaseous hydrocarbon such as butane, an air flowmeter 5, a retort 6 wherein an air preheating chamber 6a' is separated from a catalyst-packed chamber 6b with a meshy membrane 6c, a catalyst 7, a cooler 8, and a heating furnace 9. Butane 1 which is maintained at room temp. by an outfurnace piping is supplied into the air 2 heated at a high temp. in the chamber 6a' from a hole bored in an insulating material 10 which is provided through the furnace 9, and the butane 1 is rapidly heated in the chamber 6b and then mixed with the air. The butane can be heated with good heat transfer efficiency in this way, and the thermal decomposition of the butane can be surely suppressed by increasing the heating velocity of the butane.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an endothermic gas conversion method and an apparatus thereof;
In detail, an endothermic gas transformation method and apparatus that uses a catalyst to transform endothermic gas used during heat treatment such as quenching and tempering of steel parts or carburizing and quenching at a high temperature of 850 to 1100'C. It takes.

BACKGROUND ART Endothermic gas used during heat treatment such as hardening and tempering of steel parts or carburizing and quenching is conventionally produced by an endothermic gas conversion device called a so-called RX gas generating furnace.

This RX gas generator is then filled with a nickel catalyst and placed into a retort maintained at a high temperature of 850 to 1100°C.
Methane (CH4) Propane (c.

Endothermic type that supplies a mixed gas of hydrocarbon gas such as H8), butane (C4H,, ), and air, and contains C01H2, N2 as the main components, and trace amounts of CH4, ■1□o,, c. It metamorphoses gas.

Now, if we take butane as an example of a hydrocarbon gas and observe its modification reaction, in the retort, C4H16+
202 +7.52N l→4 CO+ 5 H+ 7
．． 52N reaction progresses, and at this time the following equilibrium reaction is maintained.

H2+CO2:CO+H20 CHa + COrw--2CO+2 H2CH,+H
20≠CO+3H2 Therefore, between each component, CO#23%, H2#29%
, CH, = trace ~ 0.2%, CO, - trace ~ 2.0%
, and the remainder N2 are in equilibrium with each other.

Then, when the mixing ratio of butane and air is changed, the equilibrium values of CH4, co2, H20, etc. change depending on the mixing ratio.

By the way, in this conventional endothermic gas shift method, before the mixed gas of hydrocarbon gas and air contacts the catalyst and the shift reaction proceeds, the hydrocarbon gas is thermally decomposed and soot (
If C) is produced, the equilibrium state will be disrupted, making it impossible to obtain an equilibrium gas, and there is a drawback that it will be difficult to control the carbon dynamics by C01C02.

Furthermore, there is a drawback that the soot (C) produced as described above adheres to the catalyst, resulting in a decrease in catalyst activity.

The above-mentioned drawbacks of the prior art will be explained based on a specific conventional device. In FIG.
86j! / min and air 2 8.61 / min
When a mixed gas composed of

Here, in the conventional shift conversion method, in order to prevent thermal decomposition of hydrocarbon gas in the retort 6, the rapid heating section 6a is
It has a multi-tube structure consisting of several small diameter pipes to easily absorb heat from the heating furnace and promote rapid heating of the gas. Decomposition reaction: C4H1,,→C↓+2 CHa + In order to suppress the production of soot (C) by H2, it is necessary to rapidly heat the mixed gas of air and butane.

However, as mentioned above, the retort 6 of the conventional endothermic gas shift converter has a multi-tube structure of small diameter pipes, which is designed to promote rapid heating, but cannot completely prevent the formation of tin (C). There are drawbacks that cannot be suppressed.

C0 Purpose of the Invention The present invention aims to improve heat transfer efficiency by directly mixing room temperature hydrocarbon gas with air that has been preheated to a high temperature using an endothermic gas used in an atmosphere for heat treatment of steel parts. By heating well and increasing the heating rate of the hydrocarbon gas,
It is an object of the present invention to provide an endothermic gas conversion method and apparatus that can reliably suppress thermal decomposition of hydrocarbon gas and efficiently convert endothermic gas in an equilibrium state through a catalytic reaction.

21 Structure of the Invention According to the present invention, a mixed gas of a hydrocarbon gas such as butane and air is supplied into a retort filled with a catalyst and maintained at a high temperature to produce an endothermic type gas. An endothermic gas transformation force method and apparatus for transforming gas, wherein the retort is divided into a preheating chamber and a catalyst filling chamber by a mesoche-like diaphragm, and the air is preheated in the preheating chamber and then charged with the catalyst. On the other hand, hydrocarbon gas such as butane must be preheated by piping outside the furnace to prevent thermal decomposition of the hydrocarbon gas and to efficiently obtain equilibrium gas through a shift reaction. This is an endothermic gas characterized by the fact that the hydrocarbon gas is rapidly heated and mixed with preheated air by directly feeding it into the catalyst-filled chamber, and then brought into contact with the catalyst to convert the endothermic gas into an endothermic gas. Metamorphosis method, and
The retort is arranged in a heating furnace, and the retort has an air preheating chamber and a catalyst filling chamber filled with a catalyst.
It is divided by a mesoche-like diaphragm, and at the end of the retort on the air preheating chamber side, there is an air supply pipe that supplies air to the air preheating chamber via a flow meter that measures and controls the amount of air supplied from the air supply source. The gas is connected to the catalyst filling chamber in the retort, and is piped through the heat insulating material installed on the furnace wall of the heating furnace, through a flow rate needle that measures and controls the amount of hydrocarbon gas such as butane supplied. A hydrocarbon gas supply pipe such as butane, which is guided by an external piping, is connected to the retort, and a cooler is connected to the end of the retort on the catalyst-filled λ side to cool the transformed gas. This is achieved by an endothermic gas shift device that is characterized by being able to rapidly heat and mix hydrocarbon gas using preheated air and efficiently transform endothermic gas.

E, Example Hereinafter, the present invention will be described in detail based on the accompanying drawings.

FIG. 2 shows a schematic diagram of the endothermic gas shift apparatus of the present invention. In the same embodiment, the conventional example shown in FIG.
Or equivalent parts will be designated by the same reference numerals as in FIG. 1, and their explanation will be omitted.

Further, in this example, explanation will be given using butane as an example of the hydrocarbon gas.

As is clear from FIG. 2, the configuration of the endothermic gas conversion apparatus of the present invention is such that a butane flow meter 4, an air flow meter 5, an air preheating chamber 6a', and a catalyst filling chamber 6b are partitioned by a mesh-shaped diaphragm 6c. It consists of a retort 6, a catalyst 7, a cooler 8, and a heating furnace 9.

The difference from conventional endothermic gas shift equipment is the method of supplying butane 1.

In the endothermic gas shift apparatus of the present invention, 8.6% of the air 2 is heated to a high temperature of 930°C in the air preheating chamber 6a'.
maintained at room temperature by external piping during ρ/min,
After supplying 0.86 ff/min of butane 1 from a hole drilled in a heat insulating material 10 that penetrates the heating furnace 9 and rapidly heating the butane 1 in the catalyst filling chamber 6b, Mix with air at an oxygen excess rate of 1.05,
The composition modified by the catalyst is shown in the table below.

As is clear from the table, the endothermic gas composition metamorphosed by the conventional endothermic gas shift device has lower values of COl and H2 than the equilibrium endothermic gas composition, and, moreover, as a result of the metamorphosis reaction, While the formation of tin (C) is observed, the endothermic gas composition transformed by the endothermic gas shift device of the present invention is very close to the equilibrium endothermic gas composition,
However, the production of soot (C) accompanying the metamorphosis reaction was not observed.

Effects of the Invention As is clear from the above, according to the endothermic gas transformation method and apparatus of the present invention, the endothermic gas used in the atmosphere for heat treatment of steel parts is heated to a high temperature in advance. Directly mix hydrocarbon gas at room temperature with air to transmit hydrocarbon gas! ! ) By heating efficiently and accelerating the heating rate of hydrocarbon gas, thermal decomposition of hydrocarbon gas can be reliably suppressed, and endothermic gas in an equilibrium state due to catalytic reaction can be efficiently transformed. There is.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional endothermic gas shift device, and FIG. 2 is a schematic diagram of an endothermic gas shift device of the present invention. 1-1--Butane 2-----1 Air 3--1 Endothermic gas 4--Butane flow meter 5--11--Air flow meter 6-----Retort 6 a-- --- Rapid heating section 6 a' --- Air preheating chamber 6 b --- Catalyst filling chamber 7 --- Catalyst 8 --- Cooler 9 ---- Heating furnace 10 --- Insulation material applicant: Toyota Motor Corporation

Claims (1)

[Claims] (1) Supplying a mixed gas of a hydrocarbon gas such as butane and air into a retort filled with a catalyst and maintained at a high temperature,
An endothermic gas transformation method for transforming an endothermic gas, wherein the retort is divided into a preheating chamber and a catalyst filling chamber by a mesoche-like diaphragm, and the air is preheated in the preheating chamber and then transferred to the catalyst filling chamber. On the other hand, hydrocarbon gas such as butane is supplied to the reactor via external piping without preheating, in order to prevent thermal decomposition of the hydrocarbon gas and to efficiently obtain equilibrium gas through a shift reaction. An endothermic gas transformation method characterized by rapidly heating and mixing hydrocarbon gas with preheated air by directly feeding it into a catalyst filling chamber, and bringing it into contact with a catalyst to transform endothermic gas. . 2. Supplying a mixed gas of a hydrocarbon gas such as butane and air into a retort filled with a catalyst and maintained at a high temperature,
An endothermic gas shift device that transforms an endothermic gas, the retort being disposed in a heating furnace, the retort being connected to an air preheating chamber and a catalyst filling chamber filled with a catalyst.
It is divided by a mesoche-like diaphragm, and at the end of the retort on the air preheating chamber side, there is an air supply pipe that supplies air to the air preheating chamber via a flow meter that measures and controls the amount of air supplied from the air supply source. In addition, the catalyst filling chamber in the retort is piped through a heat insulating material installed on the furnace wall of the heating furnace, and is connected to the catalyst filling chamber through a flow rate needle that measures and controls the amount of hydrocarbon gas such as butane supplied. A hydrocarbon gas supply pipe such as butane, which is led by an external piping, is connected to the retort, and a cooler is connected to the end of the retort on the catalyst filling chamber side to cool the transformed gas. An endothermic gas shift device characterized by being able to rapidly heat and mix hydrocarbon gas with preheated air and efficiently transform endothermic gas.