JPS59116115A - Method for recovering carbon monoxide - Google Patents

Abstract

PURPOSE:To recover efficiently CO from exhaust gas contg. N2, CO2 and CO by simple operation with simple equipment by allowing CO2 and CO in the exhaust gas to be adsorbed on zeolite and/or molecular sieve carbon as an adsorbent under pressure, desorbing the adsorbed CO2 and CO, and bringing them into contact with said adsorbent contg. activated carbon. CONSTITUTION:Exhaust gas to be treated such as exhaust gas from a cupola is brought into contact with zeolite and/or molecular sieve carbon as an adsorbent under pressure to separate gaseous CO2 and CO in the exhaust gas by adsorption on the adsorbent. The adsorbed gaseous CO2 and CO are desorbed and brought into contact with activated carbon or said adsorbent contg. >=30wt% activated carbon, that is, the 2nd adsorbent consisting of activated carbon and zeolite and/or molecular sieve carbon. Gaseous CO2 is selectively adsorbed on the 2nd adsorbent and captures, so desired gaseous CO can be easily separated and recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for separating -carbon oxide from exhaust gas such as Yupora exhaust gas and other exhaust gases emitted from steel works, etc., which mainly contain nitrogen scum, carbon dioxide gas, and -etized carbon gas. Regarding the method of collection.

Exhaust gas such as 10-yupora usually contains a large amount of carbon monoxide residue, about 10-odd percent or more, and although some of it is heat-recovered, most of it is hardly used effectively. It has been discarded. However, this is not only problematic in terms of air pollution prevention, but also wasteful in terms of effective use of resources and energy.

The present invention provides a new method for efficiently recovering carbon monoxide gas, which is not used effectively as exhaust gas, but is otherwise disposed of, using extremely simple equipment and operations.

That is, in the present invention, exhaust gas containing nitrogen gas, carbon dioxide gas, and -carbon oxide gas is brought into contact with an adsorbent selected from zeolite, molecular sieve carbon, and a combination thereof under pressure to remove carbon dioxide scum and -carbon oxide gas. After adsorption and separation, this is then desorbed and brought into contact with activated carbon or the above-mentioned adsorbent containing at least 30% by weight of the activated carbon to adsorb and separate carbon dioxide gas, and - carbon oxide is recovered. It concerns a method for recovering carbon oxide.

According to the method of the present invention, carbon monoxide gas can be easily and efficiently recovered from exhaust gas that was conventionally disposed of, and this is of course useful for preventing air pollution.
The recovered carbon monoxide gas can be stored and used effectively as an energy source, chemical raw material, etc. when needed.

In the present invention, first, exhaust gas to be treated, for example, decayupolar exhaust gas, is brought into contact with an adsorbent selected from zeolide, molecular sieve carbon, and combinations thereof under pressure. The exhaust gas to be treated is limited to nitrogen gas, carbon dioxide gas, and -carbon oxide gas as main components.There are no particular restrictions on the composition ratio of each gas or its origin, but as is usually seen in +5 Bora exhaust gas, approximately One containing a relatively large amount of carbon monoxide gas, about 10 to 30%, is suitable. Further, the exhaust gas is preferably subjected to dust removal treatment according to a conventional method prior to the treatment of the present invention. The adsorbents used above are selected from zeolides, carbon molecular sieves or combinations thereof. The contact conditions between the adsorbent and the exhaust gas to be treated can be determined as appropriate on the premise that carbon monoxide and carbon dioxide gas in the exhaust gas will be adsorbed and collected by the adsorbent, but usually about 3 to 9 kQ/ Pressurized conditions of dG are preferably employed, and the contact is carried out under the above-mentioned pressurized conditions, usually at a temperature of about 100° C. or less. The above-mentioned contact treatment can be carried out by various methods, but it is particularly preferable to carry out the contact treatment by using two or more columns using a pressurized ink method.

Next, in the present invention, the carbon dioxide gas and -carbon oxide scum adsorbed and collected by the adsorbent as described above are desorbed, and the carbon dioxide and -carbon scum are desorbed using activated carbon or the above-mentioned adsorbent portion containing at least 30% by weight of the activated carbon, such as activated carbon, zeolite, and molecular sieve carbon. or a combination thereof. Here, the desorption of the above-mentioned treated waste from the 4-first adsorbent is usually performed by returning the internal pressure of the column filled with the adsorbent to atmospheric pressure and flowing a part of the product carbon monoxide gas therein. This makes it easier. Further, the adsorption treatment using the second adsorbent containing activated carbon as an essential component is carried out in substantially the same manner as the adsorption treatment using the first adsorbent including zeolite. Carbon dioxide gas is selectively adsorbed and collected,
The target carbon monoxide gas is easily separated and recovered.

In particular, the second adsorbent contains at least 30% by weight of activated carbon.
It is important that the content is less than 30% by weight, which is undesirable because the ability to separate -carbon oxide gas and its recovery rate decreases.

It is most preferable to use activated carbon alone as the second adsorbent.

The carbon monoxide gas thus obtained is stored in a suitable tank or the like, and can be effectively used as an energy source, chemical raw material, etc. when necessary. Further, the carbon dioxide scum adsorbed by the second adsorbent can be desorbed by returning the system pressure to atmospheric pressure in the same manner as described above and flowing a part of the product gas.

Hereinafter, an example of the method of the present invention carried out using one of the apparatuses particularly suitable for carrying out the method of the present invention will be described in detail.

Example 1 This method was carried out using the apparatus shown in one of the attached drawings. The attached drawing is a flow sheet showing an example of an apparatus suitable for carrying out the method of the present invention. There is. FIG. 1 shows the case where tower A and tower C are in operation, and FIG. 2 shows the case where tower B and tower are in operation. Therefore, for the pulp (indicated by ○) and pressure-controlled pulp (indicated by δ) shown in each figure, the black symbol indicates that the pulp is closed. The state in which flow rate control is being performed is indicated, and the symbol with nothing attached indicates the state in which the valve is open.

In this example, columns with a diameter of 22W'jIIφ and a length of IPPB are used as columns A to B. Columns A and B are each filled with 1809 zeolide (synthetic zeolite type 4A), and columns C and is activated carbon (pore diameter 10 ~ BoAs specific surface area 120
0ffi /f) were filled and used. In addition, the exhaust gas to be treated includes 65% nitrogen gas and 1% carbon dioxide gas.
A +Yupora exhaust gas having a composition of 5% and 20% -carbon oxide residue was used.

Furthermore, all operations were carried out at a temperature of 30°C.

First, the exhaust gas to be treated was passed through the pipe (1) to the column A at a rate of 1517 minutes, and the pressure inside the column was maintained at 9 kq/dG (see Fig. 1). Then, after 15 minutes have elapsed, the pulp is switched and the waste gas stream to be treated is passed to column B, while the internal pressure of column A is returned to atmospheric pressure, and a part of the product gas is passed through pipe (2) to column A and the column The process gas adsorbed on A is desorbed and the gas is passed through the pipe (3) to the tower (see Figure 2). After another 15 minutes, the pulp was changed and the gas to be treated flowed from pipe (1) to column A.
The process gases desorbed from column B are passed through pipes (3) to column C (see FIG. 1), and this operation is repeated every 15 minutes. Thus, by operating the tower C or the tower, the target product gas (-carbon oxide gas) is recovered from the respective pipes (4).

This is collected in a storage tank (not shown). In addition, when the tower C and the tower are not in operation, a part of the product gas is passed through the pipe (4), so that the carbon dioxide gas adsorbed and collected is desorbed.1. This desorbed processing gas mainly consisting of carbon dioxide gas is recovered through the pipe (5).

Further, the gas mainly consisting of nitrogen gas passing through the towers A and B is discharged to the outside of the thread through the pipe (6).

The product residue (carbon oxide gas) thus collected from the pipe (4) has a composition of 85% carbon oxide, 10% charcoal, and 5% nitrogen gas9, and the carbon oxide gas The recovery rate was 60%. This could be reburned without the need for auxiliary fuel and could be fully utilized as an energy source.

[Brief explanation of the drawing]

1 and 2 are flow sheets showing an example of the operation of an apparatus suitable for carrying out the method of the present invention. (1)...Exhaust gas supply pipe (4)...-Carbon oxide gas recovery pipe A, D...Adsorbent packed tower (and above) Figure 1 Date Figure 2

Claims (1)

[Claims] ■ Exhaust gas containing nitrogen gas, carbon dioxide gas, and -carbon oxide residue is brought into contact with an adsorbent selected from zeolite, molecular sieve carbon, and a combination thereof under pressure to adsorb and separate carbon dioxide gas and -carbon oxide residue. Then, after desorption, it is brought into contact with activated carbon or the above-mentioned adsorbent containing at least 30% by weight of the activated carbon to adsorb and separate carbon dioxide scum, -
A method for recovering carbon monoxide from exhaust gas, the method comprising recovering carbon mide.