(154c) Comparison of Different Hydrocyclone Arrangements for the Cleaning of Contaminated Soil

The ground around gas stations is often contaminated with mineral oil. This oil adheres to the particle surface which results in an accumulation of the contaminants in the fines fraction. Cleaning of this soil is commonly effected by soil-?washing? which is basically a classification process. This classification can be carried out with a cascade of hydrocyclones. The goal of the design is to maximize the yield of soil which has been cleaned-up to a tolerable level of contamination. In the present paper the design of such a process is demonstrated by using the flowsheet simulation software SolidSim which can handle the complex stream structure of this task, above all the dependence of the contamination on the particle size. In a first step SolidSim provides an estimation of the equipment needed for a given arrangement. In the second step the overall separation efficiency of the whole process is calculated on the basis on a physical model of the hydrocyclone. Changes of the cyclone geometry, of the arrangement and of the feed stream can be handled easily with the software tool. In a case study for a gas station in northern Germany a cascade of three hydrocyclones provides the maximum yield of cleaned soil. The simulation results are confirmed by measurements.