Use of hydrocyclones with a receiving bin for cleaning circulating water of mechanical impurities

Abstract

Reduction in concentration of mechanical impurities is evaluated in the circulating flow of cleaned water, some of which has been passed through a hydrocyclone.A procedure for calculating the extent to which the solid phase is extracted into a slime-receiving bin is proposed for development of the hydrocyclone plant.Hydrocyclones are widely used in industry, for example, to concentrate and clarify suspensions, and also in processes where it is required to classify particles according to size. These vessels offer considerable advantages over centrifuges and separators: low cost, simplicity of fabrication, and operational reliability.Cylindrical-conical hydroclones with two separation products -clarified and concentrated -are utilized most frequently. In a number of cases, however, a large amount of the dispersion medium proceeds into the lower discharge during separation of low-concentration suspensions. Kalashnikov et al. [1] recommend that hydrocyclones with a bin established on a lower sand packing be used for the separation of dilute suspensions.The circulating water employed at factories usually contains a significant amount of mechanical impurities, which settle onto heat-transmitting surfaces, result in increased wear of bearing assemblies, and contribute to rapid failure of shaft seals. As a rule, cumbersome filtering equipment through which the entire liquid flow is passed is used to clean the circulating water.In the scheme proposed for the cleaning of circulating water (Fig. 1), some of the circulating water, the flow rate of which is regulated by valves 3 and 4, is passed through cylindrical-conical hydrocyclone 5, or a battery of multiple hydrocyclones. Here, the flow that is directed into the hydrocyclone may amount to only several percents of the overall flow of water circulating in the loop.Let us evaluate the reduction in concentration of mechanical inclusions in the circulating water. Let Q (m 3 ) of water containing c ini (kg/m 3 ) of solid impurities circulate within the loop; then, the content of solid phase in the flow G ini = c ini Q (kg).