DE1087580B - Process for removing organic sulfur compounds from carbon dioxide - Google Patents

Description

GERMAN

It is known that organic sulfur compounds can be removed from gases with the aid of activated carbon. The activated carbon is used either as a pure adsorbent or as a catalyst. In the latter case, the organic sulfur compounds are first catalytically converted in the presence of oxygen and water vapor on a carbon impregnated with alkali or an oxidizing agent and then deposited on the carbon. The known methods for removing sulfur compounds from gases are useless if the gases _{contain a CO 2} content of more than 5%. Even low CO ₂ contents of 5 to 10 "/ o lead to a blockage of the carbon surface and have a disruptive effect both on the catalytic conversion and on the adsorption of the converted sulfur compounds.

A process has also become known with which it is possible to use organic sulfur compounds to remove from carbon dioxide gas. After this process, the carbon dioxide gas is released along with Oxygen under increased pressure, for example between 100 to 200 at, over a after activated carbon produced using a special process. Then it has to be under pressure Carbon dioxide gas if it meets the purity conditions, such as those used in synthesis be required, should correspond, in the presence of moisture in the heat still binding over sulfur, preferably copper and nickel containing masses are performed.

The invention also relates to a method for removing organic sulfur compounds from carbon dioxide gas. According to the invention, it is based on the method described at the beginning, according to which the sulfur compounds are catalytically reacted on an activated carbon impregnated with alkali in the presence of oxygen and water vapor and then deposited. The invention is based on the surprising finding that the purification of carbon dioxide gas of organic sulfur compounds is achieved up to the synthesis purity when the gas at temperatures below 100 ⁰ C, preferably between 50 and 8O ⁰ C, wherein water vapor content of the gas 5 to 15 volume percent passes over an activated carbon with an alkali load below 0.7 mol, preferably 0.15 to 0.4 mol alkali oxide / kg activated carbon.

_{In the procedure according to the invention, the blocking of the carbon surface by CO 2} , which is peculiar to the known processes and disturbs the conversion and deposition of the sulfur compound, does not occur. In the temperature range provided according to the invention, the adsorptive capacity of the activated carbon is a method of removal

organic sulfur compounds

from carbon dioxide

Applicant:

Laboratory for adsorption technology

GmbH,
Frankfurt / M., Leerbachstr, 72/74

Dr. Karl Bratzier, Bad Homburg v. d. Height,

Dr. Claus Storp, Frankfurt / M.,

and Heinrich Kleemann, Walldorf (Hess.),

have been named as inventors

for CO ₂ so low that a disadvantageous inhibition of the conversion of the organic sulfur compounds by CO ₂ adsorption does not take place. This temperature range also allows a certain humidity to be set on the coal surface, which is required for the cleavage of the organic sulfur compounds. The stoichiometric amount is sufficient as the oxygen content. In contrast to the known method for the purification of carbon dioxide gas, which was also mentioned at the beginning, in which the gas is passed over a special coal together with oxygen under increased pressure, the invention has the advantage that the removal of the organic sulfur compounds can be carried out according to the invention in one working step without the application of pressure. There is also no need to use a special carbon.

The activated carbon for the process of the invention can be impregnated in a known manner. For this purpose, the activated carbon can be treated with alkali salt solutions, for example the carbon dioxide gas can be ammonia gas, advantageously in concentrations, when the process is carried out up to 1 percent by volume.

The exhausted activated carbon loaded with sulfate salts can, by washing out, for example with hot condensed water. After washing, the charcoal can be reassembled with alkali

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impregnated, then dried and then used again. The washed out coal but it can also just be dried and then used again in the presence of ammonia gas will.

The life of the coal is relatively long, because the periodic regenerations full original activity of the coal is restored.

Example I.

Carbonic acid gas, which was intended for urea synthesis, still contained about 15 mg org. S / m ³ . After adding 0.1 percent by volume of O ₂ , 10 percent by volume of steam and 1 percent by volume of NH _{3, the} gas was passed over activated carbon at a temperature of 65.degree. The S content in the cleaned gas was below 1 mg / m ³ . From the Α-coal 1.0 to 1.5%> S was bound until the breakthrough. To regenerate the Α-carbon, the ammonium sulfate formed was washed out with water at about 60 ° C. The washed Α-charcoal was dried with heated gas and then used again.

ag Example II

Carbonic acid gas, which originates from a carbonate wash, was saturated with water vapor at 55 ° C. and, after prior separation of H ₂ S, still contained about 15 mg of org. S / m ³ . _{0.1 percent by volume of O 2 was} added to the gas, which already had the required relative humidity. The gas was then passed at 75 ° C. over alkalized activated charcoal (2 to 4%> K ₂ CO ₃ ). The cleaning performance was around 150 m ³ gas / kg coal. The regeneration was carried out as in Example I. The washed-out activated charcoal was made alkaline again, then dried and then reused.

Claims (3)

Patent claims: 1. Process for removing organic sulfur compounds such as carbon oxysulphide, carbon disulfide, Mercaptans from carbon dioxide, characterized in that the carbon dioxide gas in Presence of oxygen and water vapor at temperatures below 100 ° C, preferably between 50 and 80 ° C, and with a water vapor content of the gas of 5 to 15 percent by volume above an activated carbon with an alkali loading below 0.7 mol, preferably 0.15 to 0.4 mol alkali oxide / kg Activated carbon is passed. 2. The method according to claim 1, characterized in that that the alkalization of the activated carbon is carried out during the desulfurization process is and that the gas to be treated for this purpose continuously ammonia gas in Concentration up to 1 percent by volume is fed. 3. The method according to claim 1 and 2, characterized in that the loaded with alkali sulfate Activated charcoal by washing with hot water, e.g. B. condensation water is regenerated. © 009 588/383 8.60