GB801657A - Process of manufacturing carbon monoxide - Google Patents

Abstract

<PICT:0801657/III/1> Carbon monoxide is produced, by continuously passing carbon dioxide upwards, at a velocity of 0.1-25 ft./sec., preferably 0.5-10 ft./sec., through a continuously descending bed of petroleum coke in a furnace maintained at a reaction temperature of 900-2000 DEG C. by the passage of an electric current through the coke. The petroleum coke is preferably low in ash and volatile contents and free flowing at the reaction temperature. It may contain less than 2 per cent, preferably less than 1.5 per cent, of ash and may be precalcined at 1000 DEG C. in the furnace to remove volatiles. It may have a particle size of 1/8 inch. The carbon dioxide may be fed at room temperature, or may be preheated, e.g. by heat exchange with the carbon monoxide produced. As shown, coke is conveyed via hopper 1, elevator 2, and valve 4 to a storage bin 3 wherein it is purged with nitrogen, or evacuated and then purged with nitrogen or carbon monoxide. The coke then passes to furnace 17, via a valve 9 automatically operated by a level senser 11, wherein it is purged with nitrogen, or evacuated, and then purged with carbon dioxide optionally followed by carbon monoxide before commencement of the reaction. The purging gases may pass in through lines 18a and 19a and out through equally spaced furnace ports 22. The furnace is brought to operating temperature by the passage of 50-75 kw. of electricity for a period of 12-24 hours between annular carbon electrodes 13 spaced 11 feet 7 3/4 inches apart. Carbon dioxide is then passed through the furnace from furnace ports 22, and carbon monoxide produced passes out through similar ports 23, 20-25 kw. of electricity are consumed per 28 lb. of carbon monoxide produced in the production of 28 lb./hour of carbon monoxide. 30-35 kw. are consumed in the production of 56 lb./hour. The current is controlled by thermoelectric elements 31. At temperatures above 1500 DEG C., the furnace may be provided with a magnesite or zirconia lining. The temperature of the lower electrode should be below 1000 DEG C. to prevent attack thereof, and is preferably below 900 DEG C. Such a temperature may be obtained by water cooling. The upper electrode may be similarly cooled. The lower electrode may be further cooled by recycling cool carbon monoxide products via ports 18a or 19a. Dust which settles on the floor of the furnace may be blown out via port 18a or 19a, or removed by means of a water-cooled tubular conveyer. The carbon monoxide produced is cooled to room temperature in cooler 26, e.g. with the aid of heat exchange with the carbon dioxide feed and/or of cooling water. The cooled carbon monoxide passes through an activated carbon absorption unit 27 to remove sulphur compounds. Two carbon absorption units may be used alternately, one being on run while the other is regenerated by blowing with steam. Carbon dioxide may be removed from carbon monoxide produced in a high through put process by washing with an aqueous solution of caustic alkali or ethanolamine. Shutting off valve 30 results in an increase in pressure at valve 29 which effects the shutting off of valve 20 and the cutting off of the carbon dioxide supply.