Effect of operating variables on the performance of dense-media cyclone — a critical study

Abstract

In a coal washery, two or more dense-media cyclones (DMCs) are normally connected in parallel to form a bank sharing a common feed pipe. Depending on the operating and design variables and on the wear and tear of the equipment, the efficiency of the cyclones would vary. Efforts were made at Tata Steel’s R&D Dept. to evaluate the efficiency of a bank of cyclones at one of its washeries. A mathematical model for the cyclones was developed using the generalized distribution curve. Co-relationships were then developed relating the coefficient of separation (showing the separation efficiency) and the Ep to the design and operating variables of the cyclones. Lower feed rates and smaller spigot diameters were found to improve the separation efficiency of the cyclone. This paper discusses the modeling and optimization studies carried out with the cyclones and the recommendations made for subsequent improvement. On implementation of the recommendation, the clean coal yield improved by 2% for the same ash content in clean coal.