How Does Petroleum Coke Benefit Industry and Everyday Life?
Petroleum coke is a byproduct of the oil refinery industry. Petroleum coke refers to all types of carbonised solids obtained in petroleum processing, including green or crude, calcined and needle petroleum coke (types of Pet coke).
Petroleum coke is a solid composed mainly of carbon. It is similar to coke, but it is derived from petroleum (coke is made from coal). Petroleum coke can be used as an industrial fuel, but there are very toxic by-products based on nickel and vanadium that make it problematic. Petroleum coke is also used in the aluminium industry and the heat treatment of steel and iron. Two types of pet coke are produced viz. Fuel-grade pet coke (80%) and calcined pet coke (20%) during oil refining.
Petroleum Coke
Applications of Petroleum Coke
Petroleum coke is a byproduct of petroleum refining, useful in the production of electrodes used as a carbon anode for the aluminium industry, graphite electrodes for making steel, solid fuel boilers used to generate electricity, as fuel in firing, and as fuel for cement, and so on.
It is classified as a bottom-barrel fuel because it is the residual waste material obtained after refining coal to extract lighter fuels such as petrol.
Petrol
It is used as a source of energy and carbon for various industrial applications.
It is used abundantly in many manufacturing industries such as cement, steel, and textiles in India as it is much cheaper than coal, has a higher calorific value, and is easier to transport and store.
Calcined petroleum coke, often low in sulphur and metallic impurities, is used to make anodes for the smelting industry.
How is Petroleum Coke Used in the Cement Industry?
Due to the characteristics of pet coke, pet coke is a very popular fuel for the production of thermal energy in the present industries. Most of it is being used by cement factories in India.
It is a product with high carbon, high sulphur, and low ash content.
It has high calorific value and low cost.
Pet coke generates more heat than coal. The combustion of pet coke requires relatively little air.
Cement
Solved Questions
1. How is petroleum coke made?
Ans: During the refining process of petroleum, a by-product with high sulphur and high carbon content is produced. The sulphur that is separated from the fuel during the refining of petroleum ends up in waste products such as pet coke.
2. Write True or False.
Petroleum Coke is more expensive than coal. - False.
Petroleum coke is a byproduct of the oil refining industry. - True.
Learning by Doing
Kids Activity: Find the 'Odd One Out’.
Kerosene
Jet oil
Gasoline
Coal Gas
Diesel
Petroleum Coke
Hint: Find one that is not a product of the oil refining industry.
Summary
As we have already read the chapter, we know petroleum coke is a valuable and essential commercial product used directly in a wide range of applications including the manufacture of aluminium fuels and many other products including steel, glass, paint, and fertiliser. This chapter was all about the application of petroleum coke.
FAQs on Uses of Petroleum Coke: Explained with Examples
1. What are the main uses of petroleum coke?
Petroleum coke, or petcoke, has two primary categories of use based on its form:
- Fuel-Grade Coke: This is the most common type. Due to its high heat and low ash content, it is widely used as a fuel in cement kilns, power generation plants, and other industrial furnaces.
- Calcined Coke: This is a purified, high-carbon form of petcoke. It is a critical component in producing anodes for aluminium smelting and graphite electrodes for electric arc furnaces used in the steel industry.
2. How is petroleum coke produced?
Petroleum coke is a carbonaceous solid material that is a final byproduct of the oil refining process. It is created through a process called 'coking,' which is a severe thermal cracking method. In a coker unit, the heaviest residual oils from crude oil distillation are heated to high temperatures, causing them to break down into lighter products and a solid, concentrated carbon material, which is petroleum coke.
3. What is the difference between green petcoke and calcined petcoke?
The main difference lies in processing and application. Green petcoke is the initial product directly from the coker unit, containing residual volatile hydrocarbons. It is primarily used as fuel. Calcined petcoke is produced by heating green petcoke to over 1200°C in a rotary kiln. This process, called calcination, removes volatile matter, increases carbon density, and enhances electrical conductivity, making it suitable for specialised applications like making electrodes for the steel and aluminium industries.
4. How does petroleum coke compare to coal as a fuel source?
Petroleum coke is often compared to coal, but they have distinct characteristics:
- Calorific Value: Petcoke has a significantly higher calorific value (more energy per unit mass) than most types of coal, making it a more efficient fuel.
- Ash Content: It typically has a much lower ash content than coal, which means less solid waste after combustion.
- Sulphur Content: This is a major difference. Petcoke has a very high sulphur content, often 3-7%, compared to coal. This can lead to higher emissions of sulphur dioxide (SO₂), a key contributor to acid rain, unless controlled by scrubbers.
5. What are the environmental concerns associated with using petroleum coke?
The primary environmental concern with using petroleum coke as a fuel is its high concentration of sulphur and heavy metals. When burned, the sulphur is released as sulphur dioxide (SO₂), which contributes to air pollution and acid rain. Additionally, petcoke can contain and release toxic heavy metals like vanadium and nickel upon combustion, which are harmful to the environment and human health if not properly managed.
6. If petcoke has environmental drawbacks, why is it so widely used as an industrial fuel?
Despite its environmental challenges, petcoke is widely used primarily for economic and efficiency reasons. As a byproduct of oil refining, it is an abundant and low-cost fuel source. Its very high calorific value provides more energy compared to the same amount of coal, making industrial processes like cement manufacturing more energy-efficient. Industries using petcoke often invest in technologies like flue-gas desulfurisation (scrubbers) to mitigate the sulphur emissions.
