JPS6265919A - Adsorbent for separating and recovering co, its production and method for separating and recovering co by using its adsorbent - Google Patents

Abstract

PURPOSE:To efficiently separate and recover high-purity CO by using an adsorbent obtained by depositing Cu(II) halide or its reduction product on zeolite wherein the molar ratio of Si/Al is regulated within specified limits. CONSTITUTION:Copper(II) halide or its reduction product is dissolved or dispersed in an org. solvent such as a lower alcohol, the soln. is brought into contact with zeolite wherein the molar ratio of Si/Al is regulated to 1-5 and then the solvent is removed. The obtained material is further heated in an inert gas or a reducing gas atmosphere to deposit the copper(II) halide or its reduction product and an adsorbent is obtained. The adsorbent is used and high-purity CO is separated and recovered from a mixed gas contg. CO by a pressure-fluctuation adsorptive separation method and/or a temp.-fluctuation adsorptive separation 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 an adsorbent used for the purpose of separating and recovering CO, and further relates to a method of manufacturing the adsorbent and a method of separating and recovering CO using the adsorbent.

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, for example, around 70 vol 1% or more, so the CO contained in these gases is If it can be separated and recovered with high purity, it can be used as a raw material for the synthesis of formic acid, acetic acid, etc., and for the reduction of organic compounds, and is extremely useful in the chemical industry.

Conventionally, methods for separating and recovering CO from gas whose main component is CO include cryogenic separation method, copper ammonia method, and kelp (
COS ORB) method is known, but these methods have the problem of high equipment costs and large costs for thermal energy such as electricity and steam, making them unsuitable for separating and recovering large volumes of CO. medium or small volume CO
was not necessarily suitable for separation and recovery. Furthermore, CO obtained by separation by these methods contains 02, C
It has the disadvantage that it cannot be used as it is for organic synthesis because it contains gas components such as O2 that are a hindrance to organic synthesis reactions.

By the way, the PSA method and the TSA method are known as methods for selectively separating a specific gas from a medium or small volume of source gas.

The PSA method is a method for selectively separating a specific gas from a mixed gas.The adsorbent is adsorbed onto an adsorbent at high pressure, and then the adsorbed material is removed by lowering the pressure of the adsorption system. This is a method of desorbing adsorbed matter and separating adsorbed matter and non-adsorbed matter.Industrially, multiple towers filled with adsorbent are installed, and in each adsorption tower, pressure is increased → adsorption →
By repeating a series of washing and degassing operations, the entire device can perform continuous separation and recovery.

Similarly to the PSA method, the TSA method is also a method for selectively separating a specific gas from a mixed gas.The TSA method is one of the methods for selectively separating a specific gas from a mixed gas. This is a method in which the adsorbed substances adsorbed to the agent are desorbed and the adsorbed substances and non-adsorbed substances are separated.

Conventionally, this PSA method was used to remove CO from a mixed gas containing CO.
A method using mordenite-based zeolite as an adsorbent has been proposed as a method for separating and recovering. (Refer to JP-A-59-22825 and JP-A-59-49818.) If-
1 As a method for separating and recovering CO from combined gas, copper halide (■), copper oxide (1), copper (II) salt, copper oxide (
A method has been proposed in which a copper compound such as II) supported on activated carbon is used as an adsorbent. (Unexamined Japanese Patent Publication No. 58
-158517, JP 59-69414, JP 59-105841, JP 59-13
(Refer to Publication No. 8134) Furthermore, as a method for removing CO from a mixed gas containing CO, the molar ratio of SiOz/A (λO) is 20 to
A method using an adsorbent in which 200% zeolite supports copper ions is also known. (U.S. Patent No. 4,01
(See Specification No. 9,879) Problems to be Solved by the Invention When implementing the PS'A method or the TSA method, the performance required of the adsorbent packed in the adsorption tower is: ■ Selectivity of the target component with respect to coexisting components ■ There is a large difference in the adsorption amount of the target component under pressure or low temperature and under reduced pressure or high temperature. ■ The adsorbed target component must be easily desorbed. ■ It is difficult for components other than the target component to be adsorbed. , and that it is difficult to detach. These performances have a significant impact on product gas purity and yield, so PSA
Act or TSA Act is an important element.

However, in the method of using mordenite-based zeolite as an adsorbent, which utilizes the physical adsorption/desorption phenomenon of the adsorbent, the pressure swing must be switched more frequently because the amount of C○ adsorption is relatively small. First, there are disadvantages in terms of operation and valve life, and the fact that CO2 must be removed in advance before adsorption operation.
, the purity of the product decreases, and the adsorbed N2. When cleaning the inside of the tower using product CO gas to remove CO, the amount of cleaning is large, resulting in problems such as a low recovery rate of product CO.

On the other hand, in a method using an adsorbent in which a copper compound is supported on activated carbon, CO, N2. When attempting to separate CO from a mixed gas containing CO, CO, etc., it is difficult to separate and recover high-purity CO because CO2, etc., tend to be co-adsorbed at the same time as CO, and the amount of CO adsorbed on the adsorbent is also high. However, there are problems with this method, such as the fact that it is not always reliable, and it has not yet reached the point where it can be adopted on an industrial scale.

Furthermore, the molar ratio of 5iOb/Aflz05 is 20 to 20
Although the method of using an adsorbent in which monovalent copper ions are supported on zero zeolite can be adopted as a method for removing CO from a mixed gas with a relatively low CO content, if the CO content is around 70,701% or For the purpose of selectively separating CO from a mixed gas containing more than that amount, it is difficult to adopt it industrially because the amount of COO deposited is small and the purity and yield of the product CO gas are poor.

In view of this situation, the present invention was achieved as a result of intensive research to find an industrially advantageous adsorbent that can efficiently separate and recover CO from a mixed gas containing CO.

Means for Solving the Problems The adsorbent for COO separation and recovery of the present invention contains copper halide (I
I) or a reduced product thereof.

In addition, the method for producing the adsorbent for COd@ recovery of the present invention involves contacting an organic solvent solution of copper(II) halide with zeolite having a Si/An molar ratio of 1 to 5, and then removing the organic solvent. It is characterized by: In this case, it is preferable to further heat-treat in an inert gas or reducing gas atmosphere after removing the organic solvent, and it is particularly preferable to use a lower alcohol as the organic solvent.

Furthermore, the method for separating and recovering CO of the present invention includes PS
When separating and recovering CO from a mixed gas containing CO by method A or/and TSA method, S is used as an adsorbent.
The present invention is characterized by using an adsorbent for recovering CO fractions, which is made by supporting copper (II) halide or its reduced product on zeolite having an i/AQ molar ratio of 1 to 5.

The present invention will be explained in detail below.

l11 An uninvented COO separation and recovery adsorbent is a zeolite with a Si/A molar ratio of 1 to 5, and a halogenated 8 (t)
I) or a reduced product thereof.

As the zeolite, a natural or synthetic zeolite having a small Si/AQ molar ratio of 1 to 5 is used.

Zeolites with a Si/Al molar ratio of less than 1 usually do not exist, whereas when the Si/Al molar ratio exceeds 5, the product CO
The purity and yield of the gas will be poor and it will no longer serve the intended purpose.

The particle size of the zeolite is not particularly limited, but it is advantageous to select it from a range of, for example, about 1 to 7 mm, taking into account pressure loss when packed in a column.

Copper (II) halide or its reduced product to be supported on the carrier made of zeolite is copper (II) chloride.
, copper(II) fluoride, copper(II) bromide, or reduced products thereof. Among these are copper(II) chloride;
or its reduced products are of greatest importance. Among the above, the reduced product is a mixture of a copper (I) compound and a copper (II) compound,
Alternatively, it is presumed to be a compound with a valence between monovalent and II-valent.

The amount of copper halide (TI) or its reduced product supported on zeolite is not particularly limited, but is usually 0.5 to 1
Om-mat/g, preferably 1-6 m-mal/
Select from the range of g. If the supported amount is too small, COO
If the loading capacity is insufficient, and on the other hand, the amount supported is too large, the separation efficiency will be reduced.

The above-mentioned adsorbent is produced by bringing an organic solvent solution of copper(II) halide into contact with zeolite having a Si/A molar ratio of 1 to 5, and then removing the organic solvent. Manufactured. It is also advantageous to further heat-treat in an inert gas or reducing gas atmosphere after removing the organic solvent; in this case, if the heat-treating conditions are severe, the supported halide m(II) is partially reduced and reduced. Become a thing.

As organic solvents, ketones, esters, 21-methyls, etc. can be used, but the best CO separation effect is achieved when lower alcohols are used, so it is preferable to use lower alcohols industrially. is particularly desirable. Here, the lower alcohols include methanol, ethanol, n-
Propertool, impropertool, n-butanol, inbutanol, 5ec-butanol, tert-butanol and the like can be mentioned. When water is used instead of the organic solvent, C○ adsorption ability is not developed.

Contact with the organic solvent solution is carried out by impregnation, spraying, etc. At this time, in addition to simply contacting the zeolite, the zeolite may be brought into contact with an organic solvent solution of copper (II) halide, or the zeolite may be brought into contact with an organic solvent solution of copper (II) halide. Deaeration may be performed under reduced pressure conditions.

The method for removing the organic solvent after contacting the zeolite with an organic solvent solution of copper (II) halide is to remove the organic solvent under reduced pressure conditions while performing heat treatment at room temperature or/and 70 to 100°C. , a method in which the organic solvent is removed by heat treatment at 70 to 100°C is employed.

- After removing the organic solvent as described above, the organic solvent is further removed under an inert gas (N?, argon, etc.) or reducing gas (CO, H2, etc.) atmosphere to
Activation is preferably carried out by heat treatment at 00°C, preferably 150 to 250°C. Through this heat treatment, the copper (II) compound supported on the carrier is partially reduced, resulting in a mixture of copper (I) and copper (II) compounds, or a valence intermediate between monovalent and II valence. It is estimated that this compound will have the following properties:

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 0~6 kg.
/ cm'LG, and the degree of vacuum in the vacuum degassing step is below atmospheric pressure, for example 200 to 1 OTo.
It is desirable to set it to rr.

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 60 to 180'C.

It is also possible to use the PSA method and the TSA method in combination, performing adsorption under low temperature conditions north of atmospheric pressure and performing deaeration under high temperature conditions below atmospheric pressure.

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 a main component, as well as carbon dioxide, methane and other hydrocarbons, water, and small amounts of H, S, NH3, and the like. In addition to converter gas, blast furnace gas, electric furnace gas, generator gas, etc. can also be used as raw material gas.

In addition, in the present invention, prior to the CO separation and recovery step,
It is desirable to provide a step for adsorption and removal of impurities such as sulfur compounds and NH3, a moisture removal step, and an O2 removal step, which may poison the adsorbent or shorten its lifespan. However, CO2, removal process and N
It is not necessary to provide a z removal process.

In industrial operations, when the PSA method is adopted, multiple adsorption towers filled with the above-mentioned adsorbent are used, and the following operations are performed in each adsorption tower: (1) Feedstock gas is passed through the adsorption tower. A process of adsorbing CO, and a process of using the exhaust gas to raise the pressure (m) of another column shortly before the CO concentration in the exhaust gas becomes equal to the CO concentration in the raw material gas. (2) After the adsorption process is completed, the A depressurization step in which the adsorption tower and the adsorption tower after vacuum deaeration are connected, and the pressure in the former adsorption tower is reduced to near atmospheric pressure in parallel flow, and a corresponding step in which the pressure in the latter adsorption tower is increased (1); (3) A cleaning step in which a part of the product gas is introduced in parallel flow into the depressurized adsorption tower to clean the residual impurity gas inside the tower, and the gas discharged at this time is used for pressurization (II) of other towers. (4) A product recovery step in which the CO adsorbed on the adsorbent is degassed in a countercurrent flow from the adsorbent by reducing the pressure in vacuum to recover the product gas; (5) The adsorption column and adsorption after product recovery have been completed. Pressure increasing (I
) step, (6) pressurization (II) step in which the pressure is increased in parallel flow with the scrubbing exhaust gas from another adsorption tower, (7) pressurization (DI) step in which the pressure is increased by the exhaust gas near the end of the adsorption step in another adsorption tower, in sequence. Just do it repeatedly.

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

The adsorption/desorption phenomenon by the solid adsorbent of the present invention is mainly based on a reversible chemical reaction (complex formation reaction and dissociation reaction) between halide m(II) or its reduced product supported on a carrier and CO. (no chemical reaction with N2.COz occurs), and is thought to be secondary to physical adsorption onto the pore surface of the zeolite and desorption therefrom.

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

Example 1 200111 (7) -c4 t@(I
I) A copper(II) chloride solution was prepared by dissolving 13 g in 40 cc of ethanol. In this solution, Si/AJI, which had been previously dried at 110°C for about 4 hours, was added.
19 g of 1.5φ columnar zeolite (Zeolum F-9 manufactured by Toyo Soda Kogyo Co., Ltd.) with a molar ratio of 1.25 was added, and after degassing with an aspirator for 10 minutes, the mixture was allowed to stand for 4 hours.

Next, while heating to 200℃ with a mantle heater, N
2. After ethanol was distilled off in an air stream, the mixture was cooled to room temperature to obtain an adsorbent for CO separation and recovery.

The adsorbent obtained in
! A mixed gas of 1 atm with a composition of CO: 71.4 vol% NL: 12.7 vol% CO2: 15.9 vat% was supplied to this adsorption tower, and CO was removed at 50°C. It was adsorbed. The amount of CO adsorption at this time is 20.0c
It was c/cc.

After the adsorption operation, the inside of the column was washed with 180 cc of CO, and then degassed for 5 minutes at a pressure of 50 Torr using a vacuum pump.
The adsorbed gas was released. The amount of CO released at this time was 8.9 cc/cc, and the recovered gas composition was CO: 95.4 vo1% COz + 4.2i vo1% NL: trace.

Example? Adsorption separation was carried out under the same conditions as in Example 1, except that the adsorption operation temperature was 80°C. The results were as follows.

CO adsorption amount 14.0 cc/cc, C○ release amount
7.4 cc/cc Recovery gas composition CO: 98.1 vo1% CO2, + 1.9 vo1% Nz: trace Example 3 A carrier with a molar ratio of Si/AJI of 1.25 1. E
An experiment was conducted under the same conditions as in Example 1, except that 19 g of 11 mφ columnar zeolite (Morregular Sieves 13X manufactured by Union Carbide Co., Ltd.) was used. The results were as follows.

CO adsorption amount 23.2 cc/ccCO release iH7
, 3cc/cc Recovery gas composition CO: 94.3 vo1% CO2,: 5.7 vo1% Nz: trace Example 4 Example 1 except that methanol was used instead of ethanol.
When an experiment was conducted under the same conditions as in Example 1, almost the same results as in Example 1 were obtained.

Example 5 In Example 1, the mixed gas adsorption operation was performed at 2 kg/am.
After the adsorption operation, the pressure was reduced to atmospheric pressure and the inside of the column was washed with 180 cc of CO. Then, degassing was performed using a vacuum pump at a pressure of 50 Torr for 5 minutes to release the adsorbed gas. The results were as follows.

CO adsorption amount 25.1 cc/ccC○ release amount
10.1 cc/cc recovered gas composition CO: 9B, 1 malo 1% CO2: 3.9 vo1% N2. : trace Comparative Example 1 An experiment was conducted under the same conditions as in Example 1 except that distilled water was used instead of ethanol. As a result, it was found that by using I distilled water as the solvent, C○ adsorption ability was not expressed and it was found to be unsuitable as a CO adsorbent - Comparative Example 2 Zeolite with a Si/Al molar ratio of 16 The experiment was conducted under the same conditions as in Example 1 except that zeolite was used, but the CO concentration in the recovered gas was quite high, and this zeolite was
It was found that this method cannot be used as an O selective separation method.

Effects of the Invention The C○ adsorbent of the present invention: ■ can be easily produced using inexpensive raw materials; ■ is stable against heat and has hardness, and has long-term durability when packed in an adsorption tower. , ■Because there is little adsorption of gases other than CO in the mixed gas,
It has excellent advantages such as being able to separate and recover high-purity CO.

Therefore, the present invention allows highly purified CO to be separated and recovered from converter gas and other CO-containing gases on an industrial scale, and is of great significance in the chemical industry.

Claims (1)

[Claims] 1. Zeolite with a Si/Al molar ratio of 1 to 5,
An adsorbent for CO separation and recovery, which supports copper (II) halide or its reduced product. 2. Production of an adsorbent for CO separation and recovery, characterized in that the organic solvent solution of copper (II) halide is brought into contact with zeolite having a Si/Al molar ratio of 1 to 5, and then the organic solvent is removed. Law. 3. After bringing an organic solvent solution of copper(II) halide into contact with a zeolite having a Si/Al molar ratio of 1 to 5, the organic solvent is removed and further heated under an inert gas or reducing gas atmosphere. The manufacturing method according to claim 2, characterized in that the method comprises: 4. The manufacturing method according to claim 2 or 3, wherein the organic solvent is a lower alcohol. 5. When separating and recovering CO from a mixed gas containing CO by pressure fluctuation type adsorption separation method and/or temperature fluctuation type adsorption separation method, as an adsorbent, the molar ratio of Si/Al is 1.
A method for separating and recovering CO, characterized by using an adsorbent for separating and recovering CO, which is made by supporting copper (II) halide or a reduced product thereof on a zeolite according to 5.