JPH064131B2 - Method for producing carbon monoxide adsorbent - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for producing a solid adsorbent used when adsorbing carbon monoxide from a mixed gas containing carbon monoxide together with nitrogen, methane, carbon dioxide, hydrogen and the like.

[Prior art]

Carbon monoxide is a basic raw material for synthetic chemistry, and is produced from coke and coal in a production furnace, water gas furnace, winker furnace, Lourgi furnace or Coppers furnace, or steam reforming from natural gas and petroleum hydrocarbons. It is manufactured by the method and partial oxidation method. In these methods, the product is obtained as a mixed gas of carbon monoxide and hydrogen, carbon dioxide, methane, nitrogen or the like. Further, carbon monoxide is obtained as a mixed gas produced as a by-product at a steel mill, an oil refinery or a petrochemical plant. In order to use these carbon monoxides as a synthetic chemical raw material, it is necessary to separate carbon monoxide from the mixed gas. As a conventional method for separating carbon monoxide, a liquid absorption method using a toluene solution of copper aluminum tetrachloride [Cu (AlCl ₄ ) ₄ ] is an industrialized method. This method has the advantages that it is not affected by hydrogen, carbon dioxide, methane, nitrogen or oxygen contained in the mixed gas, and that the absorption pressure is low.

[Problems to be Solved by the Invention]

In the above-mentioned liquid absorption method, when the absorbing liquid comes into contact with water, it irreversibly reacts with each other to lower the absorption capacity and, at the same time, generate a precipitate and further generate hydrochloric acid. Therefore, the water content in the mixed gas must be removed in advance to 1 ppm or less. Therefore, it is necessary to perform a dehydration treatment step of the mixed gas before the absorption step, and strict control is essential. Further, in this method, it is unavoidable that toluene vapor is mixed in the recovered carbon monoxide, and a device for removing this toluene is further required, and since a liquid absorbent is used, there are process restrictions. It has disadvantages such as

[Means for Solving the Problems]

One of the inventors has conducted extensive research on solid adsorbents having excellent water resistance. As a result, solid adsorbents composed of copper (I) halide, aluminum halide and activated carbon, prepared using an organic solvent such as toluene. Was completed (for example, JP-A-58
-124516 publication). The present invention significantly improves the properties of the adsorbent by improving the method for preparing this solid adsorbent. That is, a feature of the present invention is that a copper halide selected from copper (I) halide or copper (II) halide and aluminum halide are selected from water, hydrochloric acid, nitric acid, formic acid, acetic acid and aqueous ammonia. The first step of dissolving in a solvent of one or more kinds, the second step of impregnating this solution into activated carbon or graphite, and then distilling off the solvent, the activated carbon or graphite at a temperature of 80 ° C or higher, an inert gas or reducing It is a method for producing a carbon monoxide adsorbent, which comprises a third step of processing under gas flow. The first step of preparing a solution to be adsorbed on the solid adsorbent of the present invention is to add a copper halide selected from copper (I) halide or copper (II) halide and aluminum halide at 20-80 ° C. Dissolving in a solvent. Next, in the second step, activated carbon or graphite is added and mixed in this solution, and the mixture is mixed under normal pressure or preferably 100 torr.
The solution is impregnated into activated carbon or graphite under the following reduced pressure. After impregnation, the solvent is distilled off by a method such as decompression or heating. The activated carbon or graphite that has been subjected to the above treatment is used as the third step in an atmosphere of an inert gas or a reducing gas such as He, Ar, N ₂ , H ₂ or CO, at 80 ° C. or higher, preferably 150 to 300. Activate by heating at a temperature of ° C. Examples of copper (I) halide and copper (II) halide used in the present invention include chlorides, fluorides, bromides or iodides of copper (I) and copper (II). I) and copper (II) chloride are preferred because they provide high performance. It may be a mixture of copper (I) halide and copper (II) halide. Examples of aluminum halides include aluminum chloride, aluminum fluoride, aluminum bromide and aluminum iodide, and the use of aluminum chloride is particularly excellent in characteristics. When hydrochloric acid is used as the solvent, a substance that reacts with hydrochloric acid to produce aluminum chloride, such as aluminum oxide or aluminum hydroxide, can be used instead of aluminum chloride. The solvent used for producing the carbon monoxide solid adsorbent of the present invention is one or more of water, hydrochloric acid, nitric acid, formic acid, aqueous ammonia acetate, etc., and by using these solvents, The dispersibility of aluminum halide in a solid is improved as compared with the case where an organic solvent is used, thereby improving the selective adsorption and desorption of carbon monoxide. Especially, when hydrochloric acid is used as a solvent, this effect is particularly remarkable. Activated carbon or graphite is used as the adsorption medium, and as the activated carbon, any of pitch charcoal, caking charcoal and coconut husk charcoal can be used. In addition, crushed coal, shaped coal (pellets, honeycombs, etc.), fibrous carbon, etc. in terms of shape, and in addition to ordinary ones in terms of structure, for example, activated carbon for molecular sieves, etc. are used. As graphite, natural graphite or artificial graphite can be used. The solid adsorbent produced by the method of the present invention can be efficiently adsorbed carbon monoxide in a chemical plant or the like by being charged into an adsorption tower in an activated state and circulating a raw material gas. This adsorption step has a sufficient effect even when the column is operated at normal pressure, but when it is operated in a pressurized state, the adsorption amount is increased and there is an advantage that even high temperature gas can be treated. Recommended temperature for adsorption operation is -40 to 90 ° C under normal pressure,
It is preferably 0 to 60 ° C, and under pressure is -10 to 120 ° C, preferably 20 to 90 ° C. The carbon monoxide adsorbed on the adsorbent is desorbed by reducing the pressure in the adsorption tower or heating it. When desorbing by depressurization, the inside of the tower is 100 torr with a vacuum pump.
It is preferable to operate under reduced pressure. In the case of heating, it is desirable to operate at 40 to 250 ° C, preferably 60 to 180 ° C.

【Example】

Hereinafter, the present invention will be described in more detail with reference to examples. Example 1 5.0 g (50 mmo in a 100 ml two-necked eggplant flask under dry nitrogen.
Copper chloride (I) (1), 6.7 g (50 mmol) of aluminum chloride and 50 ml of 3N hydrochloric acid were added, and the mixture was stirred at 20 ° C for 1 hour to dissolve. Then, 10 g of commercially available activated carbon was added, and the mixture was further stirred for 1 hour, and then depressurized with a vacuum pump at 2 torr for 3 hours. Then, the inside of the eggplant flask was heated to 80 ° C. to sufficiently remove hydrochloric acid to prepare a copper chloride-aluminum chloride-activated carbon solid adsorbent. 5 g of the solid adsorbent thus prepared was placed in a glass sample bottle having a capacity of 30 ml and set in a constant pressure type adsorption amount measuring device, whereby the adsorption and desorption ability of carbon monoxide and carbon dioxide was measured. First, the sample bottle was placed in a constant temperature bath and heated at 180 ° C for 1 hour while passing dry nitrogen (20 ml / min) to activate the adsorbent. Subsequently, carbon monoxide gas (purity> 99.99%) was fed into the sample bottle, and the saturated adsorption amount at each temperature of 20 to 180 ° C was measured. Next, after desorbing under reduced pressure at 50 torr for 20 minutes while maintaining the inside of the sample bottle at each test temperature of 20 to 180 ° C., carbon monoxide gas was sent again to the sample bottle and each saturated adsorption amount was measured. Then, while passing dry nitrogen into the sample bottle,
After activating the adsorbent for 1 hour, carbon dioxide gas (purity> 9
9.9%) was sent to the sample bottle, and the saturated adsorption amount at each temperature of 20 to 180 ° C and the saturated adsorption amount of carbon dioxide after desorption for 20 minutes at 50 torr at each test temperature were measured. The experimental results are shown in Table 1 and FIG. Example 2 An adsorbent was prepared and activated in the same manner as in Example 1 except that 28% aqueous ammonia was used as the solvent instead of 3N hydrochloric acid. The saturated adsorption amount of each of carbon monoxide and carbon dioxide and the adsorption amount after desorption for 20 minutes at 50 torr were measured for the adsorbent prepared by using the same constant pressure type adsorption amount measuring apparatus as in Example 1.
The results were almost the same as in Example 1. Example 3 6.7 g (50 mmol) of copper (II) chloride instead of copper (I) chloride
The adsorbent was prepared and activated in the same manner as in Example 1 except that was used, and the results of determining the adsorption capacities of carbon monoxide and carbon dioxide are shown in FIG. Comparative Example 1 5.0 g (50 mmo in a 100 ml two-necked eggplant flask under dry nitrogen.
l) copper (I) chloride, 6.7 g (50 mmol) of aluminum chloride and 50 ml of toluene were added, and the mixture was stirred at 20 ° C for 1 hour,
A toluene solution of copper chloride-aluminum chloride was prepared.
Commercially available activated carbon (10 g) was added thereto, and the mixture was further stirred for 12 hours while refluxing toluene, and then depressurized at 80 ° C. and 10 torr for 3 hours to sufficiently remove toluene to prepare an adsorbent. With respect to the prepared adsorbent, the adsorption ability of carbon monoxide and carbon dioxide was measured by the same operation as in Example 1. Results are shown in FIG. Comparative Example 2 Under dry nitrogen 5.0 g (50 mmol) of copper (I) chloride was added to 50 ml of 3
An adsorbent was prepared in the same manner as in Example 1 except that the adsorbent was dissolved in normal hydrochloric acid, and the adsorption ability of carbon monoxide and carbon dioxide was measured. Results are shown in FIG. Example 4 An adsorbent was prepared in the same manner as in Example 3 except that pure water was used instead of the 3N hydrochloric acid of Example 3, and carbon monoxide and carbon dioxide were measured using the constant pressure adsorption amount measuring device. The adsorption capacity was determined. The result is shown in FIG.

【The invention's effect】

From the results of Examples 1 and 2, it is clear that the method using the adsorbent of the present invention has a larger adsorption amount of carbon monoxide than carbon dioxide and a high temperature dependence. It was also found that the amount of adsorbed carbon monoxide after desorption under reduced pressure was also highly temperature-dependent. Furthermore, the method of Example 4 using pure water as the solvent also shows relatively excellent performance, which is an advantageous method for manufacturing the adsorbent at a low cost. Comparing the adsorption / desorption abilities of the copper (I) chloride-aluminum chloride of Example 1 and Comparative Example 1 due to the difference in the solvent, the saturated adsorption amount of carbon monoxide shows almost the same performance in the entire range, but the desorption ability and the dioxide It can be seen that there is a large difference in carbon adsorption capacity. That is, when an organic solvent is used, the desorption ability is significantly reduced in the low temperature range, and the adsorption selectivity is also inferior to that of the present invention. This shows that the method of the present invention using an inorganic solvent as a solvent is clearly advantageous in separating, purifying and recovering carbon monoxide from a mixed gas containing carbon monoxide using the present adsorbent. ing. Therefore, the copper chloride-aluminum chloride-activated carbon solid adsorbent can be expected to have a greater effect in terms of adsorption selectivity, adsorption amount, etc. when prepared using an inorganic solvent such as hydrochloric acid. Further, in the copper chloride-activated carbon solid adsorbent containing no aluminum chloride described in Comparative Example 2, although the adsorption amount of carbon monoxide increases, the desorption property is poor and the physical adsorption of carbon dioxide is strong. Is clearly inferior to.

[Brief description of drawings]

Each figure is a diagram showing the saturated adsorption amount after activation of carbon monoxide and carbon dioxide and the saturated adsorption amount after desorption under reduced pressure at each temperature, and FIG. 1 shows Example 1 and FIG. Shows Example 3; FIG. 3 shows Comparative Example 1; FIG. 4 shows Comparative Example 2; and FIG. 5 shows the results of Example 4. 1A: CO adsorption amount after activation 1B: CO adsorption amount after desorption under reduced pressure 2A: CO ₂ adsorption amount after activation 2B: CO ₂ adsorption amount after desorption under reduced pressure

Claims (1)

[Claims] 1. A copper halide selected from copper (I) halide or copper (II) halide and aluminum halide are one or more solvents selected from water, hydrochloric acid, nitric acid, formic acid, acetic acid and aqueous ammonia. In the first step, the second step of impregnating this solution into activated carbon or graphite, and then distilling off the solvent, the activated carbon or graphite at a temperature of 80 ° C or higher under an inert gas or reducing gas flow. A third step of treating, a method for producing a carbon monoxide adsorbent, comprising: