The story of carbon black

What is carbon black?

Carbon black is an ingredient that is essential to making many of the products we use every day stronger, deeper in color and longer lasting. In its pure form carbon black is a fine black powder, essentially composed of elemental carbon; it is produced by partial burning and pyrolysis of low-value oil residues at high temperatures under controlled process conditions.

Carbon black is mainly used to strengthen rubber in tires, but can also act as a pigment, UV stabilizer, conductive or insulating agent in a variety of specialty rubber, plastic, ink and paint applications. Apart from tires, other everyday uses of carbon black include hoses, conveyor belts, plastics, printing inks and automotive coatings.

How is it made?

At Birla Carbon, we produce carbon black in a high temperature reactor through a tightly controlled flame-synthesis process that uses oil, and sometimes natural gas, as feedstock. The oil is usually a residue derived from crude oils or coal and is purchased from refineries, petrochemical plants and coal tar distillers.

Birla Carbon Manufacturing Film

The carbon black manufacturing process

Our six step manufacturing process

Manufacturing Process Nav
  • Carbon extraction, refinement
    and transportation
  • Manufacturing process
  • Transportation to
    customers
  • End product
Manufacturing Process
Feedstock Oil

Feedstock oil

To begin the process, preheated air and oil (and sometimes natural gas) are fed to the reactor in tightly controlled amounts.

Reactor

Reactor

Inside the reactor, the air and hydrocarbons undergo a complex set of reactions – partial combustion, thermal decomposition, particle nucleation and particle growth/aggregation. These reactions occur in temperatures up to 1,800 degrees Celsius and can take less than 0.01 of a second.

Water injection

Water injection

Water is then injected to stop the reactions by reducing the temperature of the carbon black ‘smoke’ stream leaving the reactor.

Separation

Separation

This 'smoke' stream is then routed to a baghouse that separates the carbon black from the reactor tail gas using hundreds of fabric filter bags. The carbon black is a light, fluffy powder as it exits the baghouse and is transported to an accumulator tank.

Pellet formation

Pellet formation

The carbon black powder is mixed with a binding agent and water in a pelletizer to form pellets, which are then dried in a rotary drier. This process increases its bulk density by up to five times, allowing for more efficient transportation to our customers.

Storage and packaging

Storage and packaging

In a final step, the carbon black pellets are packaged in a variety of containers, ranging from 10 kg paper bags to 60 tonne railroad cars for transportation to our customers.

By making adjustments to the reactor conditions – such as temperature, flow rates, reaction time and reactor design – we are able to produce a wide variety of carbon blacks with different morphology (specific surface area and structure level) to meet the diverse needs of all of our customers. Throughout the manufacturing process, we use distributive control systems to ensure our products meet the highest quality standards.

The carbon black manufacturing process produces large quantities of hot reactor tail gas with a heating value that can be utilized to make steam and electricity. We recover as much as possible of this tail gas energy for our own internal energy needs, but we also supply our energy surplus to businesses and homes around our sites. This greatly reduces our net greenhouse gas emissions and provides a valuable resource to our neighboring communities and partners.

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Carbon black and its challenges

Like many manufacturing industries reliant on naturally occurring raw materials, carbon black faces challenges at various stages of its production, transport and utilization, as well as public perception. Birla Carbon works to proactively resolve these challenges, and we have addressed many of them in this report.