GB840336A - Process and apparatus for producing carbon black and carbon black so produced - Google Patents

Abstract

In a carbon black furnace, which comprises in axial alignment a substantially cylindrical first reaction zone 21 having a diameter greater than its length, and a substantially cylindrical second reaction zone 37 having a length greater than its diameter, its diameter being less than that of the first zone, and which is adapted for <PICT:0840336/III/1> the formation in the first zone and passage to the second zone of an axial stream of a hydrocarbon in a surrounding spiral stream of hot combustion gas, the second zone has a diameter which is less than 3/4 of that of the first zone, and a substantially cylindrical choke 36 having an internal diameter of 40-85% of that of the second zone and having a length of 4.5-18 inches is situated in the second zone adjacent the inlet of the second zone or within 6 inches thereof, preferably within 1.5-3 inches thereof. The diameter of the first zone is preferably 2-6, more preferably 3 times the diameter of the second zone. The length of the first zone may be 0.5-2 times, and preferably the same as, the diameter of the second zone. The make hydrocarbon may be one or a mixture of two or more of natural gas, methane, ethane, propane, or butane, or an atomized or vaporized gas oil which is about 90% vaporized at 775 DEG F. The hot combustion gas may be produced by the combustion of methane, ethane, propane, butane, or natural gas containing at least 80% of methane, or an atomized or vaporized liquid hydrocarbon, with air, oxygen-enriched air, or air diluted with combustion gas. A protective and cooling gas, e.g. air, hydrogen, carbon dioxide, carbon monoxide or methane, may be passed into the furnace around the make hydrocarbon inlet pipe. A 4-inch diameter second zone may be 1-5 ft. long, and a 12-inch diameter second zone may be 2-6 ft. long.