Abstract:
A process for the removal of CO2 and/or H2S from gases containing olefins and acetylenes by absorption in an aqueous solution of an alkali metal salt of amino acid and desorption by decompressing and heating the solvent, which comprises treating the solvent, before or after desorption, with a hydrocarbon mixture substantially consisting of benzene for the purpose of removing impurities and, after said treatment, separating the hydrocarbon mixture from the aqueous solution.
Abstract:
1,133,253. Purifying ethylene. BADISCHE ANILIN- & SODA-FABRIK A.G. 17 March, 1966 [18 March, 1965], No. 11720/66. Heading C5E. Ethylene, and gas mixtures comprising predominantly ethylene (e.g. ethylene/ethane mixture from a cracker), are selectively hydrogenated for removal of minor quantities of acetylene by hydrogenation in the presence of a catalyst containing 0À01-1 wt. per cent of palladium on a carrier of silica gel having an internal surface area of 250-400 sq. m./gm. The temperature may be 50-200‹ C., the pressure 1-30 atmospheres, and the hydrogen: acetylene volume ratio 1À5 : 1-2À0 : 1. The temperature may be progressively increased as the catalyst activity decreases.
Abstract:
Carbonyl sulphide and organic combined sulphur are removed from olefin containing gases by washing under superatmospheric pressure with a caustic alkali solution of 2 to 6% by weight of the total weight of the solution at 50 DEG to 110 DEG C. in one or more reaction vessels whose exchange surface is not less than 2 sq. m./cu. m. of the hourly throughput of gas. Starting materials used may be obtained by thermal or autothermal cracking of petroleum or fractions thereof. Preferably the process takes place at 85 DEG to 95 DEG C. at a pressure of 10 to 35 atmospheres. As shown, an olefin containing gas having the composition 8.7% CO, 14.3% H2, 5.1% N2, 25.3% CH4, 8.0% C2H6, 0.4% C3H8, 29.8% C2H4, 6.8% C3H6 and 1.6% C4H8 is introduced through pipe 1 and contacts in absorption tower 2 caustic soda solution supplied in countercurrent flow through pipe 6. Tower 2 is filled with 35 mm. steel rings to a depth of 15 m., the internal diameter of the tower being 1.3 m., so that an exchange surface of about 4 sq. m./cu. m. of gas results. Purified olefin containing gas passes out through line 3 and the caustic soda solution is recycled through retention tank 8, pump 9 and heater 5. Spent liquor may be withdrawn from the system through pipe 10 and used for a preliminary purification step and an equivalent volume of fresh caustic soda solution supplied through pipe 4. The carbonyl sulphide and organic combined sulphur can thus be removed to the extent of 90% or more. Columns having suitable baffles or a packing of conventional tower packing, e.g. packed columns, bubble tray columns and bubble columns are also suitable as reactors in the process of the present invention, which may be continuous or batchwise.
Abstract:
1,155,879. Purifying ethylene/ethane mixtures. BADISCHE ANILIN- & SODAFABRIK A.G. 4 Nov., 1966 [5 Nov., 1965; 24 May, 1966], No. 49523/66. Heading C5E. Mixtures of ethylene and ethane, which have been selectively catalytically hydrogenated (e.g. over a Pd catalyst) to remove small amounts of acetylene therefrom, are treated to remove polymerization products formed during the hydrogenation by passage over a layer of coke, silica gel and/or alumina gel. The treatment is preferably conducted under the same pressure as the hydrogenation. Suitable layers of coke Rc are 2-6 metres deep, and the gas mixture is usually passed upwards through the layer, oily polymers being drained continuously or periodically from the bottom of the layer.
Abstract:
Nitric oxide is removed from gas mixtures containing carbon monoxide, carbon dioxide, hydrogen, nitrogen and saturated and unsaturated hydrocarbons, which are to be subjected to low temperature treatment, by a process comprising adding oxygen in slight excess over that required for oxidation of the nitric oxide according to the reaction 2NO + O2 --> 2NO2 and forming and separating nitrogen dioxide and any secondary oxidation products such as dinitrogen trioxide and dinitrogen tetroxide simultaneously with the removal of carbon dioxide by washing with an aqueous washing liquid under a pressure of 8-40 atmospheres in a scrubber. The wash may be sodium or potassium hydroxide or sodium carbonate. Oxygen is supplied either in the gas phase or in dissolved form in the wash liquid, which is preferably at room temperature. Nitric oxide contents of 1 p.p.m. are thus reducible to 0.01 p.p.m.