DE818346C - Process for the production of gaseous unsaturated hydrocarbons - Google Patents

Description

Process for the production of gaseous unsaturated hydrocarbons It has been found that mineral oils, tars, shale oils, liquid and fusible products of pressure hydrogenation, especially those predominantly paraffinic Nature, or their fractions, such as heavy gasoline, medium oil, heavy oil or distillation residues, also from hydrocarbon oils of hydrocarbon synthesis from carbon oxide and Hydrogen or their fractions in gaseous unsaturated hydrocarbons in good yield is obtained if the starting materials are so high, above 500 ° Temperatures, especially at 600 to 75o °, with a corresponding throughput rate via salts of polybasic acids or carbides which are stable under the reaction conditions of metals of the second group of the periodic table that derives at least 25 percent by weight of the raw material split into gaseous hydrocarbons will.

Particularly suitable catalysts are sulfates, carbonates and phosphates and carbides of magnesium, calcium, strontium, barium, zinc and cadmium in question.

You can also use naturally occurring compounds such as kieserite, Use dolomite, calcite, limestone, barite, zinc spar, apatite.

The reaction takes place at temperatures above 500 °, in particular from 600 to 750 °, and at normal, slightly increased or reduced pressure. Gases such as nitrogen, oxides of carbon, water gas, or water vapor can also be present. When carrying out the reaction, the throughput rate and the temperature used in each case are particularly important; the higher the temperature, the lower the dwell time to choose. The temperature and residence time should always be adjusted to one another so that at least 25 percent by weight of the starting material used are converted into gaseous hydrocarbons, but more appropriately, e.g. B. 30 to 5o weight percent. Here the resulting gaseous hydrocarbons contain at least about 40%, but mostly more, e.g. B. about 50 ° ro and more, gaseous unsaturated hydrocarbons, especially ethylene, as well as propylene and butylene. In addition, a larger amount of ethane is obtained, along with other saturated gaseous hydrocarbons, which can be converted into ethylene, propylene and the like by dehydrogenation. The amount of unsaturated hydrocarbons varies depending on the type of starting materials. In addition to the gaseous components, there are also liquid hydrocarbons whose content of aromatic and unsaturated hydrocarbons is higher, the lower the selected throughput rate at a certain temperature.

The mentioned catalysts can be in the form of irregular pieces, Cubes, cylinders, spheres, prisms or the like in a fixed arrangement for use. However, the catalysts can also be used in a finely divided state. The single ones However, catalyst grains should expediently be so large that they fit a zoo to 400 mesh sieve run through. The catalyst can also be used together with the vapors of the to be treated Starting material are passed through the reaction chamber. To increase the throughput speed a carrier gas, e.g. B. steam, can be used. It can also be beneficial be an enrichment in the lower half of an upright reaction vessel to take place on finely divided catalyst, while in the upper part a low catalyst concentration is used.

The movement of the catalyst in granular form is also advantageous or shaped state from top to bottom through an upright reaction vessel, whereby the reaction space remains largely filled with catalyst. The catalysts slip here at certain times, e.g. B. one hour, one or more times through the reaction space.

Both the shaped and the finely divided catalyst in motion are withdrawn from the lower part of the reaction vessel. @ie: Catalyst fractions entrained with the gas stream are separated from the vapors inside the reaction vessel or outside it. The catalyst can after its resuscitation, e.g. B. after burning off the carbon deposited on it, can be reused and z. B. at a slightly higher temperature than corresponds to the reaction temperature, be fed back to the reaction vessel. Example 1 Paraffinic petroleum gas oil. which boils from 26o to 38o ° and has a specific gravity of 0.845, is passed at 64o ° and under normal pressure over limestone at a throughput of 3.0 parts by volume of gas oil (liquid) per part of space filled with limestone and per hour. 44% of the oil results in gaseous hydrocarbons containing 28.5% ethylene, 26.5% propylene and butylene and 10.4 % ethane, and 47.5% results in liquid hydrocarbons, which consist primarily of aromatic and unsaturated hydrocarbons. The rest is residue. Example e The same gas oil is passed at 595 ° and at normal pressure over pieces of calcium carbide with a throughput of 0.6 parts by volume of gas oil (liquid) per part of space of the reaction space filled with calcium carbide and per hour. 27.39c of the oil. gaseous hydrocarbons, which are 54.8%. contain unsaturated hydrocarbons, and 68% result in liquid hydrocarbons consisting primarily of aromatic and unsaturated hydrocarbons. The rest is residue.

Claims (1)

PATE NTANSPR UCII: Process for the production of gaseous unsaturated hydrocarbons, in particular ethylene, from hydrocarbon oils or their fractions, characterized in that the starting materials are used at temperatures that are so high, above 500 °, in particular from 600 to 75o °, and with such The throughput rate adapted to the temperature used via salts of polybasic acids or carbides of metals of the second group of the periodic table which are stable under the reaction conditions ensures that at least 25 percent by weight of the starting material is added to gaseous hydrocarbons.