JPH02283608A - Method for separating and recovering carbon monoxide - Google Patents

Abstract

PURPOSE:To separate and recover CO in high purity and recovery ratio by adsorbing CO2 from a mixed gas of CO and CO2 using activated alumina or silica gel and then adsorbing the CO on an adsorbent carrying copper chloride, etc., on active carbon. CONSTITUTION:CO is separated from a mixed gas containing CO and CO2 by a pressure swing adsorption(PSA) method. In the process, the CO2 is initially adsorbed together with water using activated alumina or silica gel as a pretreating adsorbent so as to provide <=15wt.% concentration thereof. CO is then adsorbed using a post-treating adsorbent carrying copper (I) chloride or an aluminum tetrachloride complex on active carbon. The resultant CO is subsequently desorbed and recovered from the above-mentioned adsorbent.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention utilizes a pressure swing adsorption method (hereinafter referred to as PSA method) to convert a mixed gas containing carbon monoxide (hereinafter referred to as CO) into high-purity The present invention relates to a method for separating and recovering CO.

(Prior Art) It is well known that there are cryogenic separation methods, absorption methods, and adsorption methods as technologies for separating and recovering only CD from a mixed gas containing CO. Among them, in recent years, PCA has been used as an adsorption method.
Development of CO separation technology is underway.

For example, in Japanese Patent Application Laid-Open No. 59-22625, a general zeolite adsorbent is used, and since the adsorption property of carbon dioxide coexisting with carbon monoxide is greater than that of carbon monoxide, carbon dioxide is removed in the previous stage. A two-stage PSA that requires a COz-PSA to be removed and is combined with a subsequent Co-PSA.
Since it requires a device, there are disadvantages in that the process becomes complicated and the cost of the device increases.

Further, Japanese Patent Application Laid-Open No. 83-7822 proposes a method in which the adsorption/desorption process is divided into 12 steps and co is recovered in a fraction of li in one stage of PSA. Ni, Mn, Rh, Cu(I)A shown in JP-A-61-17413
The selective adsorption ability of carbon monoxide is improved by using zeolite supporting metals as an adsorbent.
A cycle has been proposed in which at least four adsorption towers are used to carry out 12 steps of preliminary pressurization, adsorption, depressurization, post-purging gas recovery, purge gas pressurization, and purge desorption recovery in one order. Although it is possible to reduce the cost of the device by using -stage PS^, on the other hand, the operation steps become multi-stage and are very complicated.

(Problems to be Solved by the Invention) The present invention provides an effective pretreatment that can separate and recover carbon monoxide with high purity and high recovery rate from a mixed gas containing carbon monoxide, carbon dioxide, nitrogen, etc. This provides a CG-PSA method using the device.

(Means for solving the problem) In a method of separating and recovering carbon monoxide from a mixed gas containing carbon monoxide and carbon dioxide using a pressure swing method, activated alumina or silica gel is used as a pretreatment adsorbent to remove carbon dioxide. Adsorb so that the concentration is 15% or less, and then use a post-treatment adsorbent with activated carbon supported with copper (I) chloride, or activated carbon with aluminum tetrachloride (I) and rum complex supported. This is a method for separating and recovering carbon monoxide, which is characterized in that carbon monoxide is adsorbed using an adsorbent, and carbon monoxide is desorbed and recovered from the adsorbent.

That is, the feature of the present invention is that as an adsorbent used for pretreatment,
It should mainly adsorb moisture and carbon dioxide while hardly adsorbing carbon monoxide, and as a carbon monoxide adsorbent, a material with higher selective adsorption performance for carbon monoxide than other component gases such as carbon dioxide should be used. It's about doing.

Examples of the former include activated alumina or silica gel. Although these adsorbents have been widely used for removing moisture, they have not been used as adsorbents for carbon dioxide.

Figures 2 and 3 show the amount of adsorption of carbon dioxide and carbon monoxide depending on the type of adsorbent, and zeolite adsorbents have been widely used because they have a large adsorption amount of carbon dioxide. In the two-stage PSA method that uses a zeolite adsorbent to remove carbon dioxide in advance, carbon monoxide is also adsorbed at the same time, resulting in a decrease in recovery rate. In view of this, the main purpose of pretreatment is to remove moisture, and the loss of carbon monoxide is prevented as much as possible without completely removing carbon dioxide.At the same time, the carbon monoxide adsorbent is It is characterized by using a material that has a very high selective adsorption of carbon monoxide with respect to carbon to adsorb only carbon monoxide to achieve high purity. Specifically, activated carbon supported with copper(I) chloride or activated carbon supported with copper(I) aluminum tetrahydride complex are preferable. The concentration is set at 15% or less because the partial pressure of carbon dioxide increases, making it impossible to selectively adsorb only carbon monoxide in the next step, and carbon dioxide also gets mixed in, reducing purity. be.

(Example) An example in which high-purity carbon monoxide was separated and purified from converter gas based on the present invention will be specifically described below.

Figure 1 shows the outline of the ps^ device of the present invention, in which the converter gas, which is a mixed gas, is compressed by compressor 1 to 2 to 3 k
g/cm'' and introduced into the pretreatment adsorption tower 2.

Here, the process of adsorbing all of the water and most of the carbon dioxide and desorbing it using the vacuum pump 3 was repeated alternately in two towers.

The mixed gas that has passed through the pretreatment adsorption tower is transferred to intermediate tank 4.
After being stored in a carbon monoxide adsorption column 5, carbon monoxide was adsorbed, and the product gas was desorbed by a vacuum pump 6 and stored in a product gas tank 7.

Table 1 shows the operation cycle of adsorption and desorption in the carbon monoxide adsorption tower.

Table 1 Adsorbent packed in pretreatment adsorption tower 2 and carbon monoxide adsorption tower 5
The second side of the table shows the results obtained by changing the adsorbent filled in the sample.

Table 2 It is most preferable to use activated alumina as the pretreatment adsorbent and activated carbon supporting copper (I) chloride as the carbon monoxide adsorption tower in terms of both the purity and recovery rate of recovered carbon monoxide. There was found.

(Effects of the Invention) According to the present invention, there is a remarkable effect that high-purity CO gas can be separated and purified from a mixed gas containing CO with a high recovery rate using a simple and inexpensive PSA apparatus.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of an apparatus showing an embodiment of the present invention, Figures 2 and 3 are zeolite-based adsorbent and activated alumina CO,
It is a figure showing adsorption performance of CO2. 1...Compressor 2...Pretreatment adsorption tower 3.
...Vacuum pump 4...Intermediate tank 5...Carbon monoxide adsorption tower 6...Vacuum pump 7...Product gas tank Diagram cot (sang) Diagram CO (I11g) Dimensions to -

Claims (1)

[Claims] 1. In a method of separating and recovering carbon monoxide from a mixed gas containing carbon monoxide and carbon dioxide using a pressure swing method,
Activated alumina or silica gel is used as a pretreatment adsorbent to adsorb carbon dioxide to a concentration of 15% or less.
Next, carbon monoxide is adsorbed using a post-treatment adsorbent made of activated carbon supported with copper (I) chloride or activated carbon supported with aluminum tetrachloride (I) complex, and the monoxide is removed from the adsorbent. A method for separating and recovering carbon monoxide, which is characterized by desorbing and recovering carbon.