DE2447910A1 - Removal of sulphur cpds from gaseous of liquid hydrocarbons - by contact with basic carbonates of transition metals, reduced in hydrogen - Google Patents

Abstract

Removal of S cpds. from gaseous or liquid hydrocarbons by contact with solid absorbents at 15-100 degrees C, derived from cpds. of formula Me2+6 Me3+2 (OH)16CO3.4H2O, by calcination and subsequent reduction in hydrogen, and in which Me2+ is Fe, Cu, Co or Ni and Me3+ is Al or Cr. Used for treatment of fractions with upper boiling limit up to 250 degrees C, e.g. refinery gases, liquid gases (e.g. propane and butane), petrol fractions and esp. kerosene fractions. The hydrocarbons can be treated in gas or liquid phase at relatively low temps. (below 100 degrees C) and sulphur contents below 1 ppm obtained, as required in jet fuels. The absorbent can be highly loaded with hydrocarbon throughputs of 1-10 kg/l/h. Where the initial S content is low, the metal content in the absorbent can be small e.g. by dispersing on an alumina-silica carrier.

Description

Process for removing sulfur compounds from gaseous and / or liquid hydrocarbons The present invention relates to a method for the removal of sulfur compounds from gaseous and / or liquid hydrocarbons by absorption by masses that contain transition metals in finely divided form. The absorption masses are made up of compounds of the general formula tZIe62 + Me23 + (0H) 16CO) * 4 H20 produced by calcination and subsequent reduction with hydrogen. When using these absorption masses, a fine desulphurization of hydrocarbon fractions is possible up to kerosene fractions with an end boiling point of 250 ° C. even at substantially Temperatures below 1000C are possible.

The use of catalysts or absorption materials, the metallic Copper or other metals in highly dispersed form stabilized on a carrier material and activated by various additives has been known for a long time. These absorption masses are used in particular to remove small amounts of oxygen from hydrogen at temperatures from 0 to 2500C.

It is also known that in the production of synthesis gases in Sulfur compounds containing hydrocarbons, such as thiophenes, mercaptans etc., to be converted into hydrogen sulfide by catalytic hydrogenation and the hydrogen sulphide formed in the process from the raffinate by stripping or lye washing or by adsorption on zinc oxide or activated carbon remove. With the aforementioned treatment, sulfur contents can be achieved with justifiable effort can be achieved in the raffinate of approx. 1 ppm. Remain in the raffinate after the catalytic Pretreatment still predominantly hydrogen sulfide: and mercaptans, i.e.

so-called reactive sulfur compounds.

However, the aforementioned methods have the following disadvantage: The application activated carbon or zinc oxide is limited to the gas phase; also is the use limited by activated carbon as sulfur adsorbent to natural gas, because of higher hydrocarbons disturb the adsorption (see Ullmanns Enzyklopadie der technischen Chemie, D. Edition (1970), supplementary volume, p. 459, in particular paragraphs 7 and 4).

The absorption of essentially inorganic sulfur compounds of zinc oxide-containing desulphurisation compounds takes place in the temperature range of 200 to 4000C. It does not run with most organic sulfur compounds quantitatively.

For some purposes, sulfur contents of approx. 1 ppm are still too high; For example, in modern jet engines, the fuel lines are used today partly made of silver or alloys containing silver. These lines are attacked by the sulfur compounds still contained in the jet fuel. Since very large amounts of fuel are enforced, occur despite the low content of sulfur compounds still have serious corrosion problems.

The aforementioned zinc oxide or activated carbon processes can e.g.

for end products of the refinery, such as liquefied gases, petrol or

Kerosene fractions, are not used because of their implementation a considerable procedural effort with the end products of the refinery had to be operated, there was therefore the task, especially for those in the Ra £ -finerie resulting end products because of the increasing demands on their sulfur-free, an economical process for removing residual amounts of sulfur is available to deliver.

The present invention relates to a method for removing Sulfur compounds from gaseous and / or liquid hydrocarbons containing them by absorption on solid absorbents. This procedure is characterized by that the gaseous and / or liquid hydrocarbons at temperatures of 15 to 1000C passes through absorbent, which consists of compounds of the general Formula Me62 + Me 7+ (0II) 16CO, 4 H20 by calcining and subsequent reduction with hydrogen.

Such absorbents can be used as absorbents for the process according to the invention into consideration, the compounds of the general formula Me62 + Me2) + (0H) 16C0) 4 H20 have been produced by calcination and reduction in a stream of hydrogen. In of the formula mentioned are Mm2 + = Fe, Cu, Co and nickel; Me3 + = Al or Cr.

In particular, the nickel compound Ni6Al (OH) 16CO) 4 H20 according to the Calcination and reduction used as absorbents. The manufacture of such Compounds as well as their calcination and reduction is interpreted in the German Patent application 2,026,282 disclosed.

The starting materials for the process according to the invention are hydrocarbons into consideration. In particular those with an upper boiling range of up to 25,000. The sulfur content of these starting materials can be up to a few ppm. In particular end products of the refinery are suitable for the process according to the invention and here in particular refinery gases, liquid gases such as propane and butane, and gasoline fractions and especially kerosene fractions.

The above starting materials are at normal pressure or elevated Pressure passed over a bed of the aforementioned absorption mass. In the Processing of the final products of the Ra £ -finerie is usually carried out under normal conditions proceed according to the method according to the invention. To be used according to the invention Absorbents contain after the reduction in the hydrogen stream mainly the metals iron, copper, cobalt and nickel in the + oxidation state O in finely divided form on the carrier Al203 or chromium oxide. In this condition These metals are so active that they form sulfur compounds at temperatures from 15 to 1000C able to absorb practically up to the detection limit. The choice of temperature depends on the raw materials used for the implementation, e.g. is for the Desulfurization of kerosene to a higher temperature in the aforementioned range than for liquefied gases, If the starting material has only small amounts of sulfur, so absorption masses can be used that have a very low metal content exhibit. The connections described in DTS2 2 024 282 can be caused by accidents on suitable large-surface aluminum oxides or aluminum oxide-silicon dioxide mixtures are diluted accordingly, so that the finished absorption masses only Have metal contents of approx. 5 percent by weight. Even with these low metal contents the absorption rate for sulfur compounds is still sufficiently high. the Absorbents to be used according to the invention can be heavily loaded. There are throughputs of 1 to 10 kg of hydrocarbon per liter of catalyst and hour possible. At higher temperatures, higher throughputs are used; also with Absorption masses which have a higher metal content, in particular nickel.

The following is the production of the absorption masses A, B, C and D. The masses A to C were made by impregnating a carrier with a metal salt solution manufactured; the mass D was produced according to the teaching of DT-AS 2 024 282, example 1.

Absorption masses A to C Calcined extrusions, consisting of $ -Al20) with a diameter of 1.5 mm, were each with such amounts one aqueous nitrate solution of silver, bismuth or copper soaked that after the thermal decomposition of the nitrates, the absorption masses each 10 percent by weight of the corresponding metal.

Absorption mass D 100 g according to the teaching of DT-AS 2 024 282, Example 1, produced nickel compound Ni6Al2 (0H) 16CO3 '4 H20 were with 590 g aluminum oxide mixed and pressed into 1.5 mm strands, dried and calcined. The mass then contained 10 percent by weight nickel.

The invention is illustrated in more detail by means of the following examples.

Example 1 To test the activity of the absorption masses A, B, C and D each 50 ml of these masses were installed in a tubular reactor and Reduced with hydrogen at 55,000 for 12 hours.

The temperature was then set to 4000, then every hour 200 ml of a down to 5 ppm desulphurized benzine with a boiling range of 600 to 1800C were passed over the absorption mass. The test results are compiled in Table I below: Table I Catalyst Active component Corrosive sulfur after DIN 51 555 in the raffinate A Ag present, strong discoloration B Bi present very strong discolouration exercise C Cu present, slight discoloration D Ni not present, no discoloration exercise The test for freedom from sulfur was carried out on the basis of DIN 51 353 as follows: A silver strip cleaned according to the provisions of the DIN standard was stored in the treated sample for 18 hours at 10,000. In the case of gaseous hydrocarbons, the silver strip was fastened in a heatable glass tube, the purified gas was passed over the silver strip at -100 ° C. If the silver strip did not discolour after this time, the product could be described as "free of corrosive sulfur" will. a The results show that under the conditions of the process according to the invention only the absorption mass D binds the reactive sulfur compounds to such an extent that no corrosive sulfur compounds could be detected when the raffinate was tested in accordance with DIN 51 353. Although the use of the absorption masses A, B and C does not belong to the state of the art, these tests were nevertheless carried out with these masses in order to show that, for example, it is not sufficient to distribute metals finely by impregnation and to distribute them after impregnation reduce in order to obtain active absorption masses on a metallic basis, but that it is only possible to carry out the process according to the invention with a special absorption mass.

Example 2 One on a cobalt-molybdenum-alumina catalyst a residual sulfur content of approx. 0.8 ppm desulphurized kerosene fraction with a Boiling range from 160 to 2400 was at 800C with a space velocity of 6.5 Liters per liter of absorption mass and hour over that to be used according to the invention Ground D. Under the same conditions, a was commercially available under the name Actimet S available Raney nickel catalyst from Dr. E. Drought Guard tested. This Raney nickel catalyst consisted of 97 percent by weight nickel.

The test results are shown in Table II; Table II Catalyst Active component Corrosive sulfur after Ni in% by weight DIN 51 353 in the raffinate D 77 not present, no coloring Actimet S 97 present, weak discolouration exercise Example) A liquid gas which consisted of 52 percent by weight of C4 hydrocarbons and 38 percent by weight of G3 hydrocarbons and still contained 7 mg of sulfur per kg of liquid gas was evaporated and passed over 50 ml of absorption mass D at 250C.

The load was 4 kg of liquid gas per liter of absorption mass and Hour. The liquid gas desulphurized in this way was at 1000C via a DIN 51 753 prepared silver lining. After 18 hours there was still no discoloration of the silver lining, i.e. the sulfur compounds were removed from the Liquefied gas removed below the detection limit.

Claims (1)

Claim Process for removing sulfur compounds from containing sulfur compounds gaseous and / or liquid hydrocarbons through absorption on solid absorbents, characterized in that the gaseous and / or liquid hydrocarbons at temperatures from 15 to 1000C via absorbent, which consists of compounds of the general formula Ne62 + Me23 + (0H) 16C05. 4 H20 by calcining and then Reduction with hydrogen have been obtained and in the Me2 + Fe, Cu, Co or Ni and Me3 + mean Al or Cr.