GB664033A - Improvements in carbon black - Google Patents

Abstract

<PICT:0664033/III/1> <PICT:0664033/III/2> In the production of carbon black by the decomposition of a hydrocarbon in a furnace heated by combustion gases, a combustible mixture of fuel gas and air or hot combustion gas is injected tangentially into one end of a furnace chamber which comprises a cylindrical body portion provided at the fuel gas injection end with a coaxial outlet conduit of smaller diameter than the chamber, and tapered at the other to a cone-shaped extension. A high velocity blast flame is produced which spirals along the furnace wall to the far end of the cone-shaped extension and returns as an inner spiral which is withdrawn from the coaxial outlet conduit. Hydrocarbon gas or liquid is separately introduced into the furnace so as to form a thin sheet at the boundary surface of the inner and outer spirals where the hydrocarbon is decomposed to form carbon particles which are withdrawn from the furnace through the outlet conduit in suspension in the furnace gas effluent. In Figs. 1 and 2, fuel gas is supplied from pipe 9 to nipples 11 and air from pipe 8, the resulting flame entering the cylindrical body 1 through burner ports 6 to form an outer spiral which is reflected from the conical portion 2 as an inner spiral, the latter being withdrawn through the tube 12. Hydrocarbon may be injected either from an adjustable inlet 14, this being preferred for gaseous hydrocarbon, or directly into the boundary surface of the spirals by pipes 16 or 17. Preferably the height/internal diameter ratio of both the cylindrical and conical portions is between 1 and 2, and the inside diameter of the outlet conduit between 0.3 and 0.7 times the internal diameter of the cylindrical body portion.