JPS61242909A - Production of adsorbent for separating and recovering co - Google Patents

Abstract

PURPOSE:To obtain an adsorbent for separating and recovering CO of high purity from a mixed gas containing the CO, by bringing a solution containing a copper (I) halide dissolved in water or an alcohol in the presence of an alkali (earth) metal salt readily soluble in water or alcohol into contact with a carrier, and drying the resultant carrier. CONSTITUTION:A copper (I) halide, e.g. copper (I) chloride, is dissolved in water or methanol, etc. in the presence of the above-mentioned alkali (earth) metal salt, e.g. LiCl or MgCl2. In this case, the amount of the above-mentioned coexisting metal salt is selected from 0.3-3mol range based on 1mol copper (I) halide. The resultant copper (I) halide solution is then brought into contact with a carrier consisting of silica or/and alumina or activated carbon and the resultant carrier is dried to give the aimed adsorbent for separating and recovering CO. The adsorbent is filled in an adsorption column and capable of separating and recovering the CO of high purity from a mixed gas containing the CO on an industrial scale by the PSA or TSA method.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for separating a mixed gas containing CO by a pressure fluctuation adsorption separation method (hereinafter referred to as PSA method) or/and a temperature fluctuation adsorption separation method (hereinafter referred to as TSA method). The present invention relates to a method for producing an adsorbent used for the purpose of separating and recovering high-purity CO.

Conventional technology Typical gases containing CO as a main component include converter gas obtained from converters in steel plants, blast furnace gas obtained from blast furnaces, electric furnace gas obtained from electric furnaces, and gasification of coke. There is a generator gas that can be obtained. Most of these gases are normally used as fuel, but some of these gases contain CO at around 70% or more, so the amount of CO contained in these gases is If CO can be separated and recovered with high purity, it can be used as a raw material for synthesizing formic acid, acetic acid, etc., and for reducing organic compounds, which is extremely useful in the chemical industry.

Conventionally, as one of the methods for separating and recovering co from a mixed gas containing co, there is a method in which copper (I) halide supported on activated carbon is used as an adsorbent, and CO is separated and recovered by the PSA method or the TSA method. is proposed. (Unexamined Japanese Patent Publication No. 58-1513517, Unexamined Japanese Patent Publication No. 59-1058
(Refer to Publication No. 41) Here, the PSA method is one of the methods for selectively separating a specific gas from a mixed gas, and involves adsorbing the adsorbent onto an adsorbent at high pressure, and then lowering the pressure of the adsorption system. The adsorbed substance adsorbed on the adsorbent is desorbed by
This is a method to separate adsorbed substances and non-adsorbed substances.

Similarly to the above-mentioned PSA method, the TSA method is also a method for selectively separating a specific gas from a mixed gas.The adsorbent is adsorbed onto an adsorbent at a low temperature, and then the temperature of the adsorption system is raised. In this method, the adsorbed substances are desorbed and the adsorbed substances and non-adsorbed substances are separated.

Problems to be Solved by the Invention However, in the methods described in JP-A-58-1513517 and JP-A-59-105841, an adsorbent in which copper halide CI) is supported on activated carbon. In manufacturing copper(I) halide, it is necessary to use solvents such as hydrochloric acid, aqueous ammonia, and acetonitrile that have irritating or foul odors and are harmful to the human body. There were problems that required special attention.

The present invention was made to find a method for producing an adsorbent that does not have such problems and has excellent CO adsorption ability.

Means for Solving the Problems The method for producing an adsorbent for CO separation and recovery of the present invention includes contacting a carrier with a copper (I) halide solution and then drying it to produce an adsorbent. , which is characterized by using a solution of copper(I) halide dissolved in water or alcohol in the presence of an alkali metal salt or alkaline earth metal salt that is easily soluble in water or alcohol; By finding a method, we have achieved the above objective.

The present invention will be explained in detail below.

In the present invention, copper halide (I) is brought into contact with the carrier.
) A solution prepared by dissolving copper halide (1) in water or alcohol is used as the solution.

As the copper(I) halide, copper(I) chloride is particularly preferred, and copper(I) bromide and copper(I) fluoride may also be used.

In addition to water, solvents include methanol, ethanol, n
- Alcohols such as propatool and isopropatool are used. Two or more types of alcohol may be used together,
Also, water and alcohol may be used together.

Since copper (I) halide does not dissolve uniformly in water or alcohol, in the present invention, an alkali metal salt or alkaline earth metal salt that is easily soluble in water or alcohol is present during its dissolution. When these salts are present, the copper(I) halide becomes soluble in water or alcohol, and a solution can be easily prepared.

Alkali metal salts or alkaline earth metal salts that are easily soluble in water or alcohol include alkali metals such as lithium, potassium, and sodium, beryllium, magnesium,
Examples include halides and nitrates of alkaline earth metals such as calcium, strontium, and barisim. Specifically, lithium chloride, potassium chloride, sodium chloride, beryllium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride, lithium bromide,
Potassium bromide, sodium bromide, beryllium bromide, magnesium bromide, calcium bromide, strontium bromide,
Barium bromide, lithium nitrate, potassium nitrate, sodium nitrate, beryllium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, barium nitrate, etc. are used.

Dissolution of copper(I) halide in water or alcohol in the presence of these salts can be achieved simply by stirring at room temperature or under heating. The amount of coexisting alkali metal salt or alkaline earth metal salt varies depending on the type of salt, the type and amount of copper(I) halide, the type and amount of solvent, the temperature conditions during dissolution, etc. It cannot be determined, but 0.3 to 3 per mole of copper halide (1)
Often selected from a molar range.

After preparing the copper(I) halide solution, this solution is brought into contact with a carrier.

Suitable carriers include silica and/or alumina and activated carbon. Zeolite can also be used, and in addition, unactivated carbon materials such as char and carbon black can also be used.

Silica is produced by, for example, neutralizing an aqueous sodium silicate solution with an acid such as hydrochloric acid to precipitate it, then washing it with water and drying it.
It is obtained by pulverizing it into powder. Alumina is obtained, for example, by precipitating aluminum hydroxide from an aqueous solution of a soluble aluminum salt, filtering it, and igniting it.

When using silica and alumina together, in addition to a simple mechanical mixture of silica and alumina, methods of kneading silica gel and alumina gel in a wet state, methods of soaking aluminum salt in silica gel, and methods of combining silica and alumina Methods of simultaneously gelling alumina from an aqueous solution, and depositing alumina gel on silica gel are employed. All of these silica, alumina and silica-alumina are commercially available.

The activated carbon may be commercially available crushed or granular activated carbon manufactured from raw materials such as palm, coal, charcoal, etc., but the activated carbon has a pore diameter of 10 Å or less, a pore volume of 0.33 ml/g or less, and a pore diameter of 20 Å or less.
Activated carbon having a pore distribution with a pore volume of 0.35 ml/g or more and a specific surface area of 1300 m''/g or more is preferred.A particularly preferred pore distribution is
The pore volume with a pore diameter of 10λ or less is 0.20 ml/g or less, and the pore volume of 20 Å to 300 people is 0.40 m.
l/g or more. Also, the specific surface area is 1400m"/g
It is more desirable that it is above. This type of activated carbon has many pores with larger diameters than general activated carbon.
It is obtained by appropriately selecting the type of raw carbon material, the type and amount of binder, activation conditions, etc.

Here, the pore volume is measured by a nitrogen gas measurement method at liquid nitrogen temperature, and in each isotherm, the relative pressure p/po
Point xs where the relationship with adsorption amount X becomes horizontal to the relative pressure axis
The pore volume was determined as vs=xs/ρ, assuming that the pores are filled by capillary condensation. ρ is the density of adsorbed gas. Further, the specific surface area is measured by a nitrogen gas adsorption method at liquid nitrogen temperature and determined using the BET formula.

There is no particular limitation on the particle size of the carrier, but in consideration of pressure loss when packed into a column, select a granular carrier with a particle size of, for example, about 1 to 7 mm, and dry it if necessary before use. do. Depending on the case, a fibrous material can also be used.

The amount of copper halide CI) supported on the carrier is selected from a wide range, but is usually 0.5 to 15 m-mat/g,
It is preferably selected from the range of 1 to 10 m-mol/H. If the supported amount is too small, the CO adsorption capacity will be insufficient, while if the supported amount is too large, the separation efficiency will tend to decrease.

The support is brought into contact with the copper halide CI) solution by impregnation, spraying, etc. At this time, in addition to simply contacting the carrier with a copper halide (1) solution by means such as impregnation or spraying, the copper halide (I) solution may be brought into contact with a carrier that has been degassed under vacuum, or the carrier may be brought into contact with a copper halide (I) solution. (I
) After contacting the solution, it may be degassed under reduced pressure conditions.

After the copper halide solution is brought into contact with the carrier, the solvent is removed by heating and drying, for example, at 100 to 500° C., preferably under an inert gas atmosphere such as nitrogen or argon.

The solvent can be removed by drying under reduced pressure as well as by heating under atmospheric pressure.

This drying yields the desired adsorbent for CO separation and recovery. Alkali metal salts or alkaline earth metal salts are attached to the adsorbent along with copper(I) halogenide, but these salts not only do not have a negative effect on the CO adsorption capacity, but rather increase the CO adsorption capacity. There is a tendency to

The adsorbent obtained as described above is packed into an adsorption tower, and CO is separated and recovered from a mixed gas containing CO by the PSA method or the TSA method.

When separating and recovering CO by the PSA method, the adsorption pressure in the adsorption step is atmospheric pressure or higher, for example 0 to 6 kg/kg.
cIlzG is preferable, and the degree of vacuum in the vacuum degassing step is below atmospheric pressure, for example 200 to 10 Torr.
It is desirable to do so.

When separating and recovering CO by the TSA method, it is desirable that the adsorption temperature in the adsorption step is, for example, about 0 to 40°C, and the degassing temperature in the degassing step is, for example, about 80 to 180°C.

It is also possible to use the PSA method and the TSA method in combination, performing adsorption at atmospheric pressure or higher under low temperature conditions and degassing at atmospheric pressure or lower under high temperature conditions.

In addition, since the TSA method is disadvantageous compared to the PSA method in terms of energy consumption, it is desirable to adopt the PSA method or a combined PSA-TSA method from an industrial perspective.

As the mixed gas containing CO that can be applied to the method of the present invention, for example, converter gas generated from a converter in a steel mill is used. Converter gas usually contains CO as the main component, as well as 02. , methane and other hydrocarbons, water and small amounts of H
, S, NH5, etc. In addition to converter gas, blast furnace gas, electric furnace gas, generator gas, etc. can also be used as raw material gas.

In the present invention, prior to the CO separation and recovery step, a step of adsorbing and removing impurities such as components that may poison the adsorbent or shortening its life, i.e., sulfur compounds, NH), and a water removal step are performed. It is desirable to provide an O2 removal step. However, the C02 removal process and Nλ
There is no need to provide a removal process.

For industrial operations when the PSA method is employed, a plurality of adsorption towers filled with the above-mentioned adsorbent may be used, and each operation illustrated below may be sequentially repeated in each adsorption tower.

(a) A step of flowing the raw material gas into an adsorption tower to adsorb CO;
Then, shortly before the CO concentration in the exhaust gas becomes equal to the CO concentration in the raw material gas, the exhaust gas is pressurized in another column (III).
(b) After the adsorption step is completed, the adsorption tower is connected to the adsorption tower that has completed vacuum degassing, and the pressure reduction step is to reduce the pressure of the former adsorption tower to near atmospheric pressure in parallel flow, and corresponding steps. (I) step of pressurizing the latter adsorption tower; (c) washing step of introducing a part of the product gas into the depressurized adsorption tower in parallel flow to wash the residual impurity gas inside the tower; (d) A product recovery step in which the gas is used for pressurization (II) in another column; (iv) a product recovery step in which the pressure is reduced to vacuum, the cobalt adsorbed on the adsorbent is degassed from the adsorbent in a countercurrent flow, and the product gas is recovered; , (e) Pressure increasing (I
) step, (f) pressurization step (II) in which the pressure is increased in parallel flow with the washed exhaust gas from another adsorption tower, (g) step (m) in which the pressure is increased by the exhaust gas from another adsorption tower near the end of the adsorption step.

By sequentially repeating the above operations in each adsorption tower in this way, highly pure CO gas can be continuously separated and recovered at a high recovery rate.

Function In the present invention, the alkali metal salt or alkaline earth metal salt exhibits the function of enabling copper halide (I) to be dissolved in water or alcohol, and the copper halide (I).
It shows the effect of enabling uniform support of I) on the carrier.

The adsorption/desorption phenomenon using the adsorbent obtained according to the present invention mainly occurs between copper(I) halide supported on a carrier and CO2.
It is based on a reversible chemical reaction (complex formation reaction and dissociation reaction) with (no chemical reaction with N, COL), and secondary physical adsorption onto the pore surface of the carrier. and withdrawal from it.

Example Next, the present invention will be further explained by giving examples.

Separation and recovery of co was carried out using an apparatus whose flow sheet is shown in FIG.

In Figure 1, (1) is an adsorption tower, (2a), (2b
).

(2c), (2d) are valves, (3) are vacuum pumps, (4) are product tanks, (a) are raw material gases, (b)
is the product Co gas, and (C) is the purge gas.

Example 1 The pore volume with a pore diameter of 10λ or less is 0.12 ml/g,
Pore diameter 20A~300 people pore volume 0.47ml/
Activated carbon having a pore size distribution of 1500 m''/g and a specific surface area of 1500 m''/g was prepared and dried in the atmosphere at 110° C. for 6 hours.

1 of the above dry activated carbon in a 20 hl Erlenmeyer flask.

Then, a solution of 4.2 g of magnesium chloride and 4.5 g of copper(I) chloride dissolved in 301 ethanol was added thereto, and after degassing with an aspirator for 1 minute, the mixture was allowed to stand for 4 hours. Next, while heating to 200°C with a mantle heater, N2. After distilling off the solvent in a gas stream, the mixture was cooled to room temperature to obtain an adsorbent for CO separation and recovery.

The adsorbent obtained above was placed in an adsorption tower (26 φ x 300 mmH
), Co: 71.4 malo 1% N2. : 12.7 malo 1% CO2: 15.9 vol 1% A raw material gas at 1 atm with a composition of
O was adsorbed. The amount of CO adsorption at this time was 17.0cc
/cc.

After the adsorption operation, the inside of the column was washed with 180 ml of CO, and then degassed for 5 minutes at a pressure of 50↑orr using a vacuum pump.
The adsorbed gas was released. The amount of CO released at this time was 8.0 cc/cc, and the CO line purity was 99.9 v.
o1%.

When adsorbed again under the same conditions as above, the amount of CO adsorbed was 8.
．． It was 0cc/cc. Thereafter, even if this adsorption-degassing process was repeated, the amount of co adsorption did not change.

Comparative Example 1 A solution of 4.5 g of copper (I) chloride dissolved in 30 ml of hydrochloric acid was added to 10 g of the activated carbon used in Example 1, and the adsorbent was produced and CO was separated and recovered under the same conditions as in Example 1. went. The results were as follows.

First CO adsorption amount 18.7 cc/ccCO
Emission amount? , El cc/ccCO purity
98.8 ma O1% CO adsorption amount after 2nd time 7
．． 8 cc/cc Comparing Comparative Example 1 and Example 1, Example 1 does not use hydrochloric acid, so it is more advantageous in terms of handling and cost, and also in terms of CO adsorption ability, Example 1 is better than Comparative Example 1. It can be seen that it is not only not inferior to, but actually slightly superior to.

Example 2 Activated carbon with a pore diameter of 10λ or less and a pore volume of 0.8
Commercially available activated carbon (Kuraray Chemical Co., Ltd.) had a pore distribution with a pore diameter of 0.09 ml/g, a pore volume of 20 to 300 ml/g, and a specific surface area of 1320 m''7 g. 4GSI (manufactured by the company) was prepared.This activated carbon was dried in the atmosphere at 110°C for 6 hours.

Adsorbent production and CO separation and recovery were carried out under the same conditions as in Example 1, except that this activated carbon was used in place of the activated carbon in Example 1. The results were as follows.

First CO adsorption amount 15. El cc/ccC
O emission amount 7.3 cc/ccCO purity
98.2 Malo 1% 2nd and subsequent CO adsorption amount 7
．． 3 cc/cc Comparative Example 2 A solution of 4.5 g of copper (I) chloride dissolved in 30 ml of hydrochloric acid was added to 10 g of activated carbon used in Example 2, and the following Example 2 was prepared.
Adsorbent production and CO separation and recovery were performed under the same conditions. The results were as follows.

First CO adsorption amount 15.1 cc/ccCO
Emission amount 7.1 cc/ccCO purity
98.0 Malo 1% CO adsorption amount after the second time 7.
1 cc/cc Example 3 Same conditions as Example 1 except that 5°Og of calcium chloride was used instead of 4.2g of magnesium chloride, and 30ml of a mixed solvent of equal volume of ethanol and water was used instead of ethanol 301. Adsorbent production and CO separation and recovery were carried out. The results were as follows.

First CO adsorption amount 18.8 cc/ccCO
Emission amount 7.8 cc/ccCO purity
9!9.9 vo1% Go adsorption amount after the second time
7.8 cc/cc Example 4 In Example 1, the adsorption operation was performed at 1 atm and 20°C,
The discharge operation was carried out at 1 atm and 120°C. The results were as follows.

First CO adsorption amount 18.8 cc/ccCO
Emission amount 17.7 cc/ccco purity
913.4 vo1% CO adsorption amount from the second time onwards
17.7 cc/cc Example 5 10 g of activated carbon in Example 1 was replaced with an average particle size of 3 mm.
Alumina (AH-Sll manufactured by Fujimi Abrasives Industry Co., Ltd.)
) Adsorbent production and CO separation and recovery were performed under the same conditions as in Example 1 except that 20 g was used. The results were as follows.

First CO adsorption amount 12.8 cc/ccCO
Release amount 5.8 cc/ccCO purity
99.9 vo1% CO adsorption amount after 2nd time 5
゜8 cc/cc Example 6 Put 20 g of silica (DC980 manufactured by Rhone-Poulenc) with an average particle size of 3 mm into a flask, and add 3 hlc7) to it.
A solution in which 15 g of lithium chloride and 4.5 g of copper (I) chloride were dissolved in water was added, and an adsorbent was produced and CO adsorption separation was performed under the same conditions as in Example 1. The results were as follows.

First CO adsorption amount 10.8 cc/ccCO
Emission amount 4.5 cc/ccCO purity
88.7!01% CO adsorption amount from the second time onwards 4.
5 cc/cc Example 7 An adsorbent was produced and produced under the same conditions as Example 6, except that silica-alumina (N831L, manufactured by JGC Chemical Co., Ltd.) was used instead of silica, and sodium nitrate was used instead of lithium chloride. CO adsorption separation was performed. The results were as follows.

First CO adsorption amount 11.3 cc/ccCO
Emission amount 4.7 cc/ccCO purity
98.2 ma O1% CO adsorption amount after the second time 4.
7 cc/cc Effects of the Invention In the present invention, copper (I) halide can be dissolved in water or alcohol by coexisting with an alkali metal salt or alkaline earth metal salt that is easily soluble in water or alcohol. As a result, it is not necessary to use solvents such as hydrochloric acid and aqueous ammonia that have irritating odors, bad odors, or are dangerous to the human body when producing the adsorbent, which is advantageous in terms of handling and cost. The CO adsorption capacity of the obtained adsorbent is not only not inferior to that when conventional hydrochloric acid or the like is used, but also tends to be improved.

In addition, as a carrier, silica or/and alumina, or a pore diameter of 10λ or less and a pore volume of 0.33ml/g
Below, the pore diameter is 20 Å ~ 300 people, the pore volume is 0.3
has a pore distribution of 5 ml/g or more and 1300 m
By using a special activated carbon having a specific surface area of ''/g or more, it becomes possible to separate and recover CO with extremely high purity compared to conventional methods.

Therefore, according to the present invention, high-purity co can be separated and recovered from converter gas and other CO-containing gases on an industrial scale, which is of great significance in the chemical industry.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing an example of a CO separation and recovery device. (1) ... adsorption tower, (2a), (2b)
, (2c), (2d)...Valve, (3)
... Vacuum pump, (4) ... Product tank, (a).
... Raw material gas, (b) ... Product CO gas, (C) ...
・Purge gas

Claims (1)

[Claims] 1. After bringing the copper halide solution into contact with the carrier,
When producing an adsorbent by drying, as the solution,
A method for producing an adsorbent for CO separation and recovery, which uses a solution of copper (I) halide dissolved in water or alcohol in the presence of an alkali metal salt or alkaline earth metal salt that is easily soluble in water or alcohol. . 2. The manufacturing method according to claim 1, wherein the carrier is silica or/and alumina. 3. The carrier has a pore diameter of 10 Å or less and a pore volume of 0.33
ml/g or less, and has a pore distribution with a pore diameter of 20 Å to 300 Å and a pore volume of 0.35 ml/g or more, and 1
The manufacturing method according to claim 1, wherein the activated carbon has a specific surface area of 300 m^2/g or more. 4. Activated carbon has a pore diameter of 10 Å or less and a pore volume of 0.2
0 ml/g or less, the pore volume of the pore diameter is 20 Å to 300 Å is 0.40 ml/g or more, and the activated carbon has a specific surface area of 1300 m^2/g or more. The manufacturing method according to scope 3.