DE764767C - Process for the production of solid paraffin from carbon oxide and hydrogen - Google Patents

Description

Process for the production of solid paraffin from carbon oxide and hydrogen It is known that the under atmospheric pressure with highly active metals B. Group of the Periodic Table, in particular with cobalt, carried out catalytically Gasoline synthesis from gases containing carbon monoxide and hydrogen aliphatic hydrocarbons of various boiling points, including solid paraffin, arise. Depending on Depending on the working conditions, the amount of paraffin formed varies between ¢ and ioo / o. In terms of quantity, it is far below the other reaction products, most of which leave the reaction space in vapor or gas form. The proportionate small amounts of paraffin that remain on the catalyst can after completion a trial period, d. H. after several weeks or months, out of the catalyst can be removed by extraction or other known means.

When performing gasoline synthesis, it is generally most beneficial to if for every i kg of cobalt or, which is roughly equivalent, for every io 1 contact room every hour about 1 cbm of a carbon oxide-hydrogen mixture for conversion comes. With this ratio of the amount of gas to be converted to the contact or contact space can at the beginning of an operating period about 100 g, after 6 to 8 weeks still about 80 g of reaction products per cubic meter of synthetic gas are obtained. Will only 5oo.'o or only too'o of the mentioned hourly gas volume through the contact trauma then there is a slight increase in the yield. but because of the unfavorable space-time yield that occurs at the same time is not economically viable seems more portable. The synthesis is carried out under atmospheric pressure. so remains even with a reduced gas flow rate or with an increased reaction time the nature of the reaction products is essentially unchanged. The reaction products consist almost entirely of c71, gasoline and gaseous. not condensable Colil hydrogen.

Carbon oxide and hydrogen have also been found on cobalt catalysts under increased pressure, e.g. B. at> or So at, brought to a halt. With these Tests started with the consideration of the amount of gas to be converted from, if there is a pressure increase, z. B. five times. per unit of time also the five times the amount of gas (enjoy at atmospheric pressure) sent through the apparatus can be. In doing so, one abandoned the conditions analogous to other processes conduct. In the work known so far, either independent pressure was used worked with approximately the same residence time of the gases in the reaction space or the synthesis is carried out with resting gases in closed vessels, or the The influence of the gas residence time was not taken into account in any more detail.

In contrast, it has now been found. that in the catalytic overpressurized column oxyhydrogenation only then optimal yields of solid material at room temperature that come close to theory Paraffin can be achieved. if one is contrary to previous views the gas residence time is approximately the same as that which is used in each case Synthesis pressure increases. The contact time is under gas residence time understood between catalyst and synthesis gas. In the case of a continuously carried out It is synthesized on the one hand by the length of the contact layer and on the other hand determined by the gas flow rate.

If, for example, you want optimum yields of solid hydrocarbons at a synthesis pressure of 5 atm, you need approximately five times as much. at 2o at but work with about twenty times the gas residence time. If, contrary to this rule, only the hall length of stay is used for 2o at, then the yields are already ttin 30 his ; oo.`o lower, nevertheless taking into account adjustment of the gas pressure the length of stay ' is still twice as high. like that at at optimal gas residence time. One of the work according to the invention generally longer gas stay does not bring such a significant improvement in yield with it that it is economically just would be finished. -With resting gases results even a substantial deterioration the synthesis results because in this case the resulting products for an inadmissibly long time exposed to the effects of contact are. Particularly beneficial results. so- probably with regard to the output per cubic meter accessible hydrocarbon output today as well as in terms of contact lifespan, arise when with one Synthesis pressure of about; by 2o at inven- appropriately with a five-bi: twenty-fold increased gas residence time is being worked. Since inan here cobalt is used as the contact material used. must be below 2; 0- the synthesis temperatures worked «-erden. Do you lead the. resulting reaction arms by jZ @ asserkühltuig a1>. then becomes 1111 The reaction space is expediently the same Maintain the work pressure that the Has use coming cooling water. Between the reaction space and the cooling water in this case there is no pressure difference, so that the synthesis device itself especially simple. _111 hand of the following execution for example, the procedure may be explained in more detail "-earth. Exemplary embodiment A produced by precipitation, from cobalt. Contact consisting of thorium and kieselguhr was first tested for its effectiveness at atmospheric pressure with a gas mixture consisting of 1 volume part carbon oxide and 2 volume parts hydrogen. Here it turned out. that z. B. with an hourly throughput of 100 1 synthesis gas per liter of contact space. ie with a gas residence time of about 1; up to 20 seconds at igo = a maximum gas contraction of 800% '0 with the formation of mostly liquid hydrocarbons. An increase in the gas throughput as well as an increase or decrease in the temperature caused a significant deterioration in the yields. on the one hand by the undesired formation of gaseous hydrocarbons, on the other hand by incomplete conversion.

In order to produce solid paraffin instead of the liquid hydrocarbons according to the invention, the synthesis pressure was increased to several times the atmospheric pressure and the gas residence time was increased accordingly at the same time The operating temperature was therefore initially necessary at 180 ° below 10 atm and a gas residence time ten times that of synthesis at atmospheric pressure, and later at 20 ° below 15 atm and 15 times the residence time.

The best yields, namely about 15o to 16o g of solid and liquid Hydrocarbons per cubic meter of synthesis gas (based on a mixture of i volume C O to 2 volumes of H2) was obtained at a pressure of 5 to 20 at. After one year The same contact without regeneration still provided approximately 100 operating times g hydrocarbons per cubic meter of synthesis gas.

Approximately 60% of the reaction products obtained had a boiling point above 300 ° and were a pure white, odorless paraffin which was solid at room temperature and which melted clear at about 100 °. The remaining 40% of the synthesis products consisted of higher-boiling oil, gasoline and gaseous, easily condensable hydrocarbons. The paraffin obtained can be used for all possible purposes. With regard to. the high yield that can be achieved according to the invention can be used, for example, for the production of olefins and knock-resistant mineral spirits. It is particularly suitable for the production of fatty acids.

If one wants to work with the same pressure to simplify the synthesis furnace in the contact and water room, then the above-mentioned yields can be achieved at temperatures of 175 to 205 ° below "8 to 17 atm with eight to seventeen times the gas residence time.

Claims (1)

PATENT CLAIM: A process for the production of paraffin, solid at room temperature, from carbon oxide and hydrogen-containing gas mixtures over cobalt or cobalt mixed catalysts at pressures above 2 at, in particular at 5 to 20 at, and at a temperature below 25o °, characterized in that with a residence time of the gases works, which compared to the determined at atmospheric pressure, in terms of the yield of liquid hydrocarbons, optimal residence time is extended approximately proportionally to the increase in pressure. To delimit the subject matter of the invention from the state of the art, the following publications were considered in the grant procedure: German Patent No. 505: 159; British Patent No. 293 572; Fuel Chemistry Vol. 12 (1c931), p. 368.