ES369396A1 - Procedure for the production of black of smoke. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

In the formation of carbon black by the pyrolysis of a hydrocarbon feed, the feed is mixed with a first quantity of hot gas to effect dilution and dispersal of the hydrocarbon feed throughout said gas, the temperature of said gas being sufficient to raise the temperature of the feed to a point which is below that at which carbon black is formed and within 600 to 1200 F. thereof then a second quantity of hot gas is added to the resulting mix to raise the temperature to the temperature at which carbon black is formed, the hot gaseous mass so formed being passed to a zone in which the carbon black is formed and recovering the black as product from the effluent of this zone. The hot gas is preferably a combustion gas obtained by burning a fuel in the presence of a free oxygen containing gas. The first quantity of combustion gas may be formed using an oxygen containing gas containing less than the stoichiometric amount of oxygen required for the complete combustion of the fuel and for the second quantity of combustion gas the free oxygen containing gas may contain more than the said stoichiometric amount of oxygen. Preferably the amount of free-oxygen containing gas used in the first combustion is 2-30% of the total free oxygen containing gas used in the process. In the first heating step the temperature is preferably raised to 1300 to 800 F. below the lowest carbon black formation temperature for that particular feed. The lapse of time between mixing the first and second hot gas streams may be 0À0025 to 0À010 seconds. The feed may be introduced into the upstream end of an elongated generally cylindrical reactor 1, the two quantities of hot gas being introduced at two points, e.g. inlets 16 and combustion chamber 4, spaced from one another along the axis of the reactor. Preferably as shown the furnace comprises three axially aligned zones, the diameters of the first and third being less than that of the second, the first quantity of hot gas being introduced in the first zone, e.g. through inlets 16 in two oppositely directed radial streams, the second quantity of hot gas being introduced in the second zone. The preferred free-oxygen containing gas is air. The furnace may include an annular combustion chamber 11 coaxially surrounding the first zone, one or more conduits, e.g. 13, 14 being adapted to feed a combustible gas mixture into the chamber.