GB1359216A - Process and apparatus for producing carbon black - Google Patents

Abstract

1359216 Carbon black CABOT CORP 8 June 1971 [8 June 1970] 19362/71 Heading C1A In producing carbon black, a fluid fuel from inlet 2 and air from inlet 14 is burned in a zone 12 at a pressure at least 1À0 p.s.i. greater than the pressure in the subsequent zone 60, and the combustion products discharged from the downstream end of zone 12, the combustion products are then accelerated in zone 28 to a kinetic head above 1À0 p.s.i. and a velocity less than sonic, and then the feedstock is injected via nozzles 44 substantially transversely into the accelerated combustion gas stream in zone 40 so as to penetrate to a depth of at least 15% of the cross-sectional dimension of said stream without substantial dilution thereby, the feedstock being injected as at least one coherent stream comprising a combustible carbonaceous liquid having a carbon content of at least 75 wt. per cent and at a rate sufficient to attain a temperature in the resulting mixture of 2400‹ F. and carbon forming conditions, the reaction mixture is then maintained in zone 60 for a time sufficient to form carbon black, the resultant product quenched via nozzles 62 to below carbon forming temperatures and the carbon black collection from downstream exit 66. The expression air is used in the present Specification to include any mixture of substantially non-oxidizing gases, e.g. N 2 , CO 2 and argon with oxygen wherein the oxygen concentration of the mixture is between 10 and 50 vol. per cent, and the expression substantially transversely means from 45 to 135 degrees relative to the axis of flow of the combustion gas stream. Preferably the feedstock is introduced as a plurality of streams through a series of nozzles 44 arranged around zone 40. The preferred feedstock is petroleum distillate or cycle stock which is injected to a depth between 15 and 50% of the cross section of the gas stream whilst the kinetic head ratio between the liquid feedstock stream and the combustion product stream is maintained between 1 : 20 and 1 : 200, the pressure in zone 12 being between 1À5 p.s.i. and 10 p.s.i. greater than the pressure in zone 60. The acceleration of the combustion gas may be achieved by flowing the gas through a convergent zone 28 as it is discharged from zone 12. Details of air/fuel ratios, residence times, and degrees of combustion are given. The combustion chamber 12 is preferably made from metal and water cooled. In a further embodiment (Fig. 2, not shown) the combustion chamber comprises a refractory lined enclosure, and air is charged into the chamber via a plurality of radially oriented conduits extending through the refractory, the fuel injector being positioned axially. The zone 40 into which feedstock is injected is preferably of a smaller cross-sectional area than the largest cross-sectional area of zone 12, the cross-sectional area of zone 60 preferably being substantially greater than that of zone 40. The zone 40 may comprise a water cooled metal conduit 42.