Carbon black for low-hysteresis rubber compositions

Claim 2

A process for making carbon black having a tint residual -6 or less, comprising the steps of: (a) passing a vortex of hot combustion gases through a reaction flow passage in a carbon black reactor having in series a first section of a first diameter, a second section having an inlet of a second diameter smaller than said first diameter and an outlet of a third diameter, and a third section of a fourth diameter larger than said third diameter, said reaction flow passage abruptly widening from said second section to said third section so that by passing the vortex of hot combustion gases from said second section to said third section said gases are rapidly expanded; and (b) introducing a hydrocarbon feedstock radially into said hot combustion gases at a location in said third section adjacent the reactor wall and in the proximity of the abrupt diameter change between the second section and the third section.

Claim 3

A process as in claim 1 wherein the fourth diameter is 2 to 5 times larger than the third diameter.

Claim 4

A process as in claim 2 further comprising introducing a hydrocarbon feedstock into the second section.

Claim 5

A process as in claim 3 wherein said vortex of hot combustion gases passing through the second section is passed through a zone of restriction having a fifth diameter smaller than said second and said third diameters.

Claim 6

A process as in claim 4 wherein the first diameter is about 9 to 12 inches and the first section has a length of about 3 to 6 inches; and wherein the second diameter is about 2 to 4 inches and the second section has a length of about 6 to 18 inches, and wherein the second section has a venturi shaped choke with a length of about 3 to 9 inches and a throat diameter of about 1 to 2 inches, the diameter of the throat being the fifth diameter; and wherein the third diameter is about 2 to 4 inches.

Claim 7

A process for making carbon black having a tint residual of less than -6 and a tint value of less than 100 comprising: (a) passing a vortex of hot combustion gases through a reaction flow passage in a carbon black reactor having a first section of a first diameter, a third section of a third diameter, and a second section having a minimum diameter and an inlet converging from a second diameter smaller than said first diameter toward said minimum diameter; said second section positioned between said first and third sections with said inlet adjacent said first section, and said reaction flow passage abruptly widening from said second section to said third section so that by passing the vortex of hot combustion gases from said second section to said third section said gases are rapidly expanded; and (b) introducing a hydrocarbon feedstock axially into said vortex of hot combustion gases at a location adjacent the reactor wall at the upstream end of the first section.

Claim 8

A process for making carbon black having a tint residual of less than -6 and a tint value of less than 100 comprising: (a) passing a vortex of hot combustion gases through a reaction flow passage in a carbon black reactor having a first section of a first diameter, a third section of a third diameter, and a second section having a minimum diameter and an inlet converging from a second diameter smaller than said first diameter toward said minimum diameter; said second section positioned between said first and third sections with said inlet adjacent said first section, and said reaction flow passage abruptly widening from said second section to said third section so that by passing the vortex of hot combustion gases from said second section to said third section said gases are rapidly expanded; and (b) introducing a hydrocarbon feedstock axially into said vortex of hot combustion gases at a location adjacent the reactor wall at the upstream end of the first section.

Claim 9

A process as in claim 6 wherein the third section is adjacent the minimum diameter of the second section and the third diameter is 2 to 5 times larger than the minimum diameter of the second section.

Claim 10

A process as in claim 7 wherein the vortex of hot combustion gases is produced by combusting natural gas with about 50% by volume excess air and introducing the combustion products tangentially into the first section.

Claim 11

A process as in claim 8 wherein the first diameter is about 9 to 12 inches, wherein the second diameter is about 2 to 4 inches and wherein the minimum diameter of the second section is about 1 to 2 inches.

Claim 12

A process as in claim 9 wherein the first section has a length of about 3 to 6 inches; and wherein the second section has a length of about 3 to 8 inches and is frustoconically shaped and coverges in a downstream direction at an angle between the reactor axis and the frustoconical surface in the range of about 10° to about 18°.