GB673776A - Improvements in the manufacture of carbon black - Google Patents

Abstract

Carbon black is produced by flowing a gaseous stream composed wholly or in part of hydrocarbons containing not less than two carbon atoms per molecule as a confined stream into a highly heated zone containing reactive oxygen, the temperature of the zone being at least as high as the hydrocarbon kindling temperature, and shielding the gaseous stream for a substantial distance within the zone by flowing in contact with and surrounding it a stream of combustible gas free from oxygen, e.g. natural gas, or oil refinery tail gases, and supplying heat for decomposing the inner stream by combustion of the outer stream. This process may be applied to any furnace carbon black process, but is particularly described and illustrated in relation to (1) a free flame process wherein hydrocarbon make gas streams flow into a quiescent stream of air flowing up and around the make gas streams in a furnace chamber, and (2) a blast flame process wherein make gas is injected, in a direction parallel or at right-angles to the axis of the furnace chamber, into a turbulent stream of blast flame gases, produced by combustion of air and fuel gas, flowing through the furnace chamber. The make gas injection tubes described consist of a thin walled metal tube enclosed in a concentric refractory tube and the end is preferably recessed from the end of the refractory tube to prevent unnecessary coking. The ratio of the velocities of the inner to the outer streams should be 0.5 : 1 to 6 : 1 to prevent excessive turbulence. Specifications 654,864 and 655,799 are referred to.