At the initial stage, carbon nuclei or precursors formed from the oil combine to form aggregates. The reaction is stopped at suitable points by direct quenching with water, at predetermined locations with predetermined quantities. The entire operation of flow, including the temperature measurements is controlled by computer-supervised electronic instrumentation.

Effluents from the reactors are essentially carbon-laden flue gases containing some combustibles. These gases are at a temperature between 700^oC and 900^oC. This heat is first utilised in preheating incoming process air in an air preheater and then reused to heat incoming Carbon Black feed stock in an oil preheater. This process maximises heat recovery and process efficiency. The effluents from the reactors pass into an inline boiler and then into a common header called smoke header.

The smoke header leads the carbon-laden flue into the main bag filter. Inlet of the flue is controlled at about 280^oC. The main bag filter is a filter house consisting of multi-cylinders, where Carbon Black is filtered. Clean gases containing combustibles pass out of the filter to the Carbon Black pellet dryer. Carbon black is recovered from the bag filters by reverse flow of the flue gases into the cylinders, performed in rotation one at a time. Carbon Black thus released from the bags accumulates in the hopper and is dropped into a pneumatic conveying line through air lock valves. Two pneumatic conveying fans draw carbon black from underneath the hopper.

Loose Carbon Black and the conveying gases are drawn through two micro pulverisers and transferred to the accumulator tank through a conveying cyclone separator. The purpose of this cyclone is to separate Carbon Black from the conveying gas. Loose Carbon Black from the cyclone separator falls into the accumulator tank and the conveying gas is drawn by a return fan and returned to the smoke header at the bag filter inlet.

Carbon Black collected in the accumulator tank is in a fluffy, powdery form, and being difficult to handle as such, has to be pelletised. Pelletisation is achieved in a proprietary machine called wet pelletiser where the loose Carbon Black is mixed with a near equal quantity of water and small quantities of pellet binders. An indirectly fired rotary drum dryer is used to dry the wet pellets. Drying is achieved by burning the part of the waste gases from the main bag filter in a specially designed combustor. Water vapour from the dryer is drawn by an exhaust blower and the exhaust or purge gas exits to the atmosphere.

The entire operation is completely automatic, achieved by sophisticated electronic distributed control system of instrumentation. The dried Carbon Black is lifted by a bucket elevator and passed through a scalper screen — to separate lumps from the product- and a magnetic separator — to separate accidental contamination of Carbon Black by magnetic particles — before discharging into product storage tanks by product screw conveyors. Lumps separated from the product are returned for reprocessing.