JPS6197123A - Method for recovering co from gaseous mixture containing co - Google Patents

Abstract

PURPOSE:To recover economically CO from a gaseous mixture contg. CO by a dry process in a high yield by treating the gaseous mixture by a specified two-stage system. CONSTITUTION:A gaseous mixture contg. CO such as a gaseous mixture consisting of about 20% CO, about 20% CO2 and about 60% N2 exhausted from a blast furnace in an iron mill is introduced into a reactor 1 packed with a catalyst such as Ni supported on alumina, and C is deposited by a reaction represented by equation I. The treated gas is introduced into a separator 2 to remove N2, and it is fed to the reactor 1 after adding CO2 from an external source in a joining part 3 as required. In the reactor 1, a reaction represented by equation II is carried out to recover CO.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is applicable to blast furnace exhaust gas discharged from a blast furnace in a steel mill, for example, where CO gas is about 20% CO gas and CO2 gas is about 20%
The present invention also relates to a method for recovering CO gas in a high yield from a CO-containing mixed gas containing about 60% N2 gas as a main component by a dry method.

Conventional technology and its problems The CO-containing mixed gas discharged in large quantities from blast furnaces in steel plants is
Currently, it is mainly used as fuel,
No other particularly effective use has been found. Therefore, separating and recovering only CO gas with high utility value from the mixed gas is attracting attention. However, the reality is that specific means for such CO recovery methods have not yet been developed.

Therefore, an object of the present invention is to provide a method for recovering CO gas from a CO-containing mixed gas by a dry method with a high yield.

In this specification, all percentages representing percentages are calculated on a capacity basis unless otherwise specified.

Means for Solving Problems In the CO recovery method according to the present invention, C is precipitated from CO gas in a CO gold-containing mixed gas according to the reaction formula 2 (% ()), and then the precipitated C is placed in a CO2 atmosphere, and the reaction formula % ( ) is characterized in that CO gas is generated from C.

The reactions of the above reaction formulas (I) and (If) are all carried out in the presence of a catalyst. As a catalyst, preferably Ni1Fe
1Co is used, and further WlMOlRu, Pt1R
Metals such as h are used. Further, these metals are preferably used in the form of being supported on a porous carrier such as alumina in order to increase the efficiency of contact with gas.

The reaction conditions for precipitating C from CO gas according to reaction formula (I) are determined by the composition ratio of the mixed gas, but 1. In order to prevent the precipitated C from dissolving and penetrating into the catalyst, it is preferable to increase the reaction pressure and lower the reaction temperature as much as possible.

In order to generate CO gas from precipitate C by placing precipitate C in a CO2 atmosphere according to reaction formula (I), there is a method of switching the gas flowing to the reactor from a CO-containing mixed gas flow to a CO2 gas flow (based on the attached drawing). (described later), or a method in which the precipitated C is taken out from the downstream of the CO-containing mixed gas together with the catalyst and transferred to the downstream of the CO2 gas.

Since the reaction system of reaction formula (II) contains an excess of CO2 gas in addition to the target CO gas, the mixed gas of the same reaction system is treated with a basic CO2 absorption liquid to produce the same wave. C.O.
2 gases are absorbed, and only CO gas is separated and recovered.

The ideal flow of the CO recovery method according to the present invention is shown in the accompanying drawings.

In the figure, (1) is a reactor filled with catalyst, (2)
is a separation device that separates CO2 gas from the reaction gas, (3)
The amount of CO2 supplied from outside the system is 1! i It is a confluence section that matches CO2. The solid line in the figure indicates that the CO-containing mixed gas is passed through the reactor (1) to precipitate C according to the reaction formula (I), and the by-produced CO2 gas and the N2 gas not involved in the reaction are separated by the separation device (1). 2) shows the flow of separating CO2 and recovering the separated CO2.The broken line shows the flow of separating CO2 (2) and recovering the separated CO2.
If necessary, supplementary CO2 from outside the system joins this part (3)
The flowchart shows a flow in which CO gas is produced by passing CO gas (added in step 1) through the reactor (1) according to the reaction formula (n).

Effects of the Invention Since the CO recovery method according to the present invention is configured as described above, CO gas having high utility value can be recovered in high yield from a co-containing mixed gas such as blast furnace exhaust gas in a steel plant.

Examples 8 to 14 Activated alumina crushed into mesh pass size was immersed in a 0.5 mol/l Nt(Now)z aqueous solution to support approximately 5% by weight of Ni(NOa)2 as Ni. A Ni alumina catalyst was prepared. Then the same catalyst 20
Q has an outer diameter of approximately 15II1111 and a length of 300111[1
A steel cylindrical reactor is filled with H2 at 1 atm.
Treat the catalyst for 4 hours at a temperature of 4o'c under gas flow,
Activated.

Then, a CO-containing mixed gas consisting of 20% CO gas and 80% N2 gas was flowed into the reactor at a flow rate of 1 liter/min at 1 atmosphere and a temperature of 400° C. for 2 hours.

As a result, C was deposited on the catalyst. As a result of measuring 00211 degrees using a non-dispersive infrared spectrometer at the gas outlet of the reactor, it was found that the amount of C precipitated was 0.13 g.

Next, CO2 gas was flowed into the reactor at a flow rate of 0°5/min at 1 atmosphere and a temperature of 400°C. After analyzing the outlet gas of the reactor and confirming the production of CO gas, the reaction is carried out in an air washing bottle (filled with a CO2 absorption liquid consisting of approximately 20% methanolamine aqueous solution) installed on the downstream side of the reactor. Passed the gas. When the gas after passing was analyzed by gas chromatography, it was confirmed that it was 98% or more CO gas. When this CO generation operation was continued for 4 hours, about 0.151 of CO gas of the above purity was recovered.

[Brief explanation of drawings]

The drawing is a flow sheet showing the CO recovery method. (1)...Reactor, (2)...Separation device. that's all 4 people outside

Claims (1)

[Claims] C is precipitated from CO gas in a CO-containing mixed gas by the reaction formula 2CO→C+CO_2...(I), then the precipitated C is placed in a CO_2 atmosphere, and C is precipitated by the reaction formula C+CO_2→2CO...(II). characterized by generating CO gas from
A method for recovering CO from CO-containing gas.