GB849169A - Carbon black producing furnace - Google Patents

Abstract

<PICT:0849169/III/1> In a cylindrical furnace, for the production of carbon black by the decomposition of a substantially linear stream of make hydrocarbon in a surrounding spiral stream of hot combustion gases, which furnace is divided into two reaction zones 21 and 37 of equal diameter by a choke 36, the length of the first zone is 2.5-3.5 times its diameter, the length of the choke is 1/2 -2 times its minimum diameter, the sum of the lengths of the first zone and the choke is less than the length of the second zone, and the minimum diameter of the choke is 1/2 -\ba3/4 that of the first zone. The choke may be cylindrical (as shown) or Venturi shaped (not shown). Oxygen-containing gas may be injected tangentially through four ports 29 (two being shown) by means of a pump. A small quantity of cooling gas, i.e. air, hydrogen, carbon monoxide, carbon dioxide, methane, or a mixture of two or more of these gases, may be passed around the make hydrocarbon injection pipe 22 through a pipe 23, which may have a flared outlet 28. The outlet end of pipe 22 may be recessed in outlet 28 (as shown), or may extend into first zone 21 (not shown). Pipe 22 may be supported in pipe 23 by a spider and may have a spray cap (Fig. 4, not shown). The make hydrocarbon may be a gas, e.g. methane, ethane, propane, butane, or a mixture of two or more of these gases, or an atomized or vaporized liquid, e.g. a gas oil which is 80% vapour at 775 DEG C. The oxygen-containing gas may be air, oxygen enriched air, or air diluted with combustion product gases. All or a portion of the make hydrocarbon and oxygen-containing gas may be pretreated. Pretreating may be by conventional indirect heat exchange tube heaters or by indirect heat exchange with the product before removal of carbon black. The product may be quenched by spraying with water from nozzles 44, or may be cooled slowly by indirect heat exchange with the atmosphere through the walls of the discharge conduct. After further water cooling, if desired, the carbon black may be removed from reaction product gas in a cyclone separator. A number of runs specifying the dimensions of furnace, and rate of flow of oil and air into the furnace are given in Tables I and II.