Comparative Properties of Bituminous Coal and Petroleum Coke as Fuels in Cement Kilns
By Jagrut Upadhyay and Narayana Jayaraman
Bituminous coal has been in use as fuel in cement kilns for a long time. With coal costs continuously rising, cement plants have been looking for alternative less expensive fuels. Petroleum coke presents a viable alternative because of its lower cost since it is a byproduct of the refining process. It has a high heat value and low ash content, which favor its use in cement kilns. However, petroleum coke presents some challenges, such as high sulfur content and poor grindability, compounded by the need to grind it finer due to a low volatile content.
The following table provides a comparison between bituminous coal and petroleum coke with respect to their characteristics and operational and emission aspects. The comparison is on a very broad basis and an evaluation is required for each specific coal and petcoke origin.
Table 1. Comparison Between Bituminous Coal & Petroleum Coke
- Petroleum coke is a viable alternative fuel to Bituminous Coal provided the challenges associated with it are properly addressed.
- The quality of Petroleum coke varies from source to source. Depending on the refining process, various types of Petroleum coke are produced.
- To ensure a successful operation, a detailed study based on the characteristics of the raw material and Petroleum coke to be used is required.
- Additional investment may be envisaged for incorporating technology that supports use of Petroleum coke as fuel and for controlling environmental emission levels.
- The use of petroleum coke may be limited by its high sulfur content. Technological measures such as finer grinding, pre-calciners designed to have a higher retention time, an external combustion chamber before the calciner, a special high-momentum kiln burner, etc. will help to effectively utilize Petroleum coke.
- Based on the quality of Petroleum coke, typically a mixed fuel firing is designed. The percentage of Petroleum coke is determined based on quality and operational trials.
About the Author(s)
Mr. Jayaraman has over 48 years of experience in the cement industry with expertise in plant conceptualization, layout, various operating systems, process calculations, production optimization, and Waste Heat Recovery (WHR) based power projects for cement and lime plants. He has led several studies to estimate realistic waste heat for power generation. He has had in-depth exposure to the technical, economic, and commercial aspects of large cement projects, and extensive experience in the upgrade and optimization of existing plants. He earned a BS in Mechanical Engineering from Osmania University, Hyderabad, India, and an MS in Mechanical Engineering from the Indian Institute of Technology, Kharagpur, India.
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