DE888240C - Process for the production of higher hydrocarbons - Google Patents

Description

Process for the production of higher hydrocarbons In the case of the catalytic Production of higher hydrocarbons from gas mixtures that is at least as much Containing carbon oxide as hydrogen is the use of iron catalysts known, the ialus suitable iron compounds were obtained by decomposition. Here find reaction temperatures of about 230 to 3200 and reaction pressures of 2 to 100 at use. The yields of liquid that can be achieved in this way However, hydrocarbons are only minor. In addition, such iron catalysts have insufficient lifespan.

It has been found that one can also with I by the decomposition of iron compounds produced iron contacts over long operating times to good yields liquid and solid hydrocarbons obtained when the catalysts are in front of the Synthesis, inside or outside the contact apparatus, initially with ordinary people or at another pressure that is lower than the subsequent synthesis pressure, pretreated with a gas containing carbon dioxide at temperatures from about 240 to 2500 will.

Further details can be found in the following exemplary embodiment evident.

D o u s e p o rt a p i t a catalyser was found at Temperatures up to about 3000 produced by thermal decomposition on iron nitrate Iron contact use. Based on its iron content, it was made with 0.25% potassium carbonate alkalized. This contact filled one in granulated or pressed Form or in connection with inert carriers in a contact apparatus, the while keeping the reaction temperature constant, the resulting Heat of reaction made possible.

After filling the contact was first with a coal oxide-containing gas mixture pretreated, for example with the one used below Synthesis gas containing 2 parts of hydrogen for every 3 parts by volume of carbon oxide. These Pretreatment took place under atmospheric pressure at 240 to 2500 and became 5 to Continued for 10 hours. Then came between carbon oxide and hydrogen as a result a gas contraction of about 30% occurs when the reaction occurs. At about the same temperature the gas pressure was increased to 15 atm after this time, whereby one per kilogram of contactis-encontent brought about 400 l of a carbon oxide-hydrogen gas mixture to reaction every hour, which contained 2 parts of hydrogen for every 3 parts of carbon dioxide. Immediately after the increase in pressure increased the contraction to about 55%. That after removing the resulting Residual gas remaining hydrocarbons contained about 50 to 70% carbonic acid and only a little water.

If the temperature is slow, i. H. increased by about 2 to 30 times a week the carbon-hydrogen conversion could be constant for half a year Be kept high. Approximately every normal cubic meter of synthesis gas was produced 110 g of liquid hydrocarbons. Of this, about 75% boiled in the range from 30 to I800. The content of unsaturated hydrocarbons increased during the mentioned Operating period from around 40 to 70%. The petrol obtained in this way provided a valuable and sufficiently knock-proof motor fuel. The existing one But olefin content favored a, also its other chemical processing, z. B. the use for the production of synthetic lubricating oils.

In addition to the low-boiling liquid hydrocarbons were still considerable amounts of easily liquefied hydrocarbons (gasol) obtained, up to 30 g per cubic meter of synthesis gas. Due to its high olefin content this gasol is also well suited for chemical processing, z. B. on polymer benzine, lubricating oils or alcohol.

For the technical implementation of the gasoline synthesis one is possible low reaction temperature is particularly important.

The lower the synthesis temperature, the larger they are Yields of valuable liquid and solid hydrocarbons and the life span of the iron catalyst and the lower the risk of carbon deposition on the catalyst. The reaction itself is strongly exothermic, but must, if a rapid stalling of the catalyst should be avoided, while remaining as constant as possible Temperature. The dissipation of the positive reaction heat takes place technically with the help of pressurized water.

The generally tubular reaction spaces are closed built into a pressurized water boiler for this purpose. Since the water vapor pressure at 2000 15 at, at 250 ° 40iat and a little over 300c is already 100 at, the apparatus must the more pressure-resistant, db. be built with the greater the wall thickness, the higher the Synthetic templating lies. The simplest possible design for the technical Implementation of the synthesis equipment is necessary for economic efficiency Synthesis essential.

In order to be able to work at the lowest possible temperature, mani have a particularly active iron catalyst available. For the activity the type of pretreatment of the catalyst is decisive. While cobalt or nickel catalysts before the synthesis with hydrogen at elevated temperatures reduced and thus brought to an activity suitable for synthesis can, is such a hydrogen treatment for iron catalysts that b! ei should work at low temperatures, not suitable. For making more active For iron catalysts, a simple reduction is not sufficient; carbon must be used be stored in a certain way. This is achieved through a pretreatment with Gases containing carbon monoxide.

This process was known as formation.

On the basis of the present invention, the formation with carbon oxide leads containing gases only to the goal if it is carried out at printing that are significantly below the synthesis pressure.

This can be clearly seen from the following comparative information.

A catalyst made from iron oxide was used, which except for 0.25% potassium carbonate contained no additives. Same samples of this catalyst were, after various pretreatments at 15 at and 2500 with a synthesis gas put into operation, which contained carbon oxide and hydrogen in a ratio of 3: 2, 41 per 10 g of iron per hour. The gas contraction that occurred was used as a measure of the conversion chosen. As in the reaction in addition to liquid and gaseous hydrocarbons carbonic acid is also produced, the contraction is in the best case about 55 bis 58%.

I. Before the synthesis, the catalyst was treated with hydrogen (4 1 / log Fe / h) pretreated for 24 hours at 1 at and 250 °.

After switching to synthesis, the contraction was 0%. she rose slowly to a maximum of 300/0 within .3 days to after a few Time to fall off again.

Pretreatment with hydrogen at 325 ° and Ilat brought the same unsatisfactory results, as well as a hydrogen treatment at 450 ° and 1 at and one at 325 ° and 0.1 at.

2. An identical catalyst was used under the synthesis conditions given above with the aforementioned carbon-hydrogen mixture directly under Printing put into operation. Here, the formation process should be carried out when printing the Synthesis going on.

The contraction was 0% at the beginning, 5% after 1 day and 5% after 5 days 150/0. An increase in conversion was only possible through a substantial increase in temperature achievable. A contraction of 46% was only reached at 290 °. Since with this Temperature, however, already has a strong tendency to form gaseous hydrocarbons was present, the yields of higher hydrocarbons remain unsatisfactory.

3. The same catalyst was used for 24 hours before synthesis pretreated at 1 at and 250 ° with synthesis gas (CO: H2 = 3: 2).

After switching to 15 at, the contraction was immediately 55%. The high turnover was sustained for many months.

If the pretreatment of the iron catalyst was carried out at 0.1 at, then the synthesis temperature could even be reduced to 230 ° with full conversion.

The contraction was 0% at the beginning, 5% after 1 day and 5% after 5 days 15%. An increase in conversion was only possible through a substantial increase in temperature achievable. Only at 2905 was a contraction of 46% reached. Since with this Temperature, however, already has a strong tendency to form gaseous hydrocarbons was present, the yields of higher hydrocarbons remain unsatisfactory.

4. The same catalyst was used for 24 hours before synthesis at 1 ast and 2500 pretreated with synthesis gas (CO: H2 = 3: 2).

Only one pretreatment with synthesis gas is used here understood, in which work is carried out up to a gas contraction of about 300/0.

After switching to 15 at, the contraction was immediately 55%. The high conversion was sustained for many months.

Claims (1)

PATENT CLAIM: Process for the production of higher hydrocarbons from gas mixtures which contain at least one part of hydrogen per part of hydrogen, by means of iron catalysts, obtained from iron compounds by decomposition were, at temperatures of, about 230 to 3200 under pressures of 2 to 100 at, characterized in that a catalyst is used, which initially with ordinary Pressure or another pressure that is lower than the pressure at the subsequent carried out synthesis, with a gas containing carbon monoxide at temperatures has been pretreated from about 250 °.