Designing coal preparation circuit for cleaning high ash and high sulfur Punjab (Pakistan) coal to meet end-user requirements

ABSTRACT

Modern coal preparation plants are designed to achieve maximum overall clean coal yield with an acceptable amount of impurities to meet end-user requirements. LIMN is commonly used to design and simulate coal processing circuits based on size and density distribution data of coal. In this study, particle distribution data for size, density, and floatability were established for Punjab coal after crushing it to 38 mm. Punjab coal contains high amounts of ash (34.70%) and sulfur (8.34%). Float-sink tests conducted on several size fractions disclosed that 16% target ash could be achieved at an overall yield of 63% with ash and sulfur rejection values in the range of 72.63–94.18% and 73.01–88.45%, respectively. However, the sulfur limit of 1.0% would be difficult to meet. Dell release analysis performed on – 0.25 mm fraction revealed poor flotation response of Punjab coal. Several process flowsheets were designed and simulated using LIMN to generate data for yield, ash and sulfur. End-User Beneficiation Number (EBN) was introduced and utilized for determining the best processing option that can provide maximum yield while meeting the quality requirements of the end-user. Economic analysis involving CAPEX, OPEX, and payback period validated the merit of EBN.

KEYWORDS:

• LIMN
• coal circuit design
• coal cleaning
• float-sink
• Punjab coal
• end-user beneficiation number

Acknowledgments

The authors express their sincere thanks to David Wiseman Pty Limited for providing Limn Flowsheet Process software and are grateful to David Wiseman for his guidance during simulation work.