DESIGN AND ECONOMIC-ANALYSIS FOR CONTINUOUS COUNTERCURRENT PROCESSING OF MILK-FAT WITH SUPERCRITICAL CARBON-DIOXIDE

Fractionation of anhydrous milk fat using supercritical CO2 provides various fractions of different physicochemical and functional properties that should enhance its utilization. Based on a mass transfer study of a pilot plant setup of a continuous countercurrent fractionation of anhydrous milk fat by supercritical CO2, economic analysis of manufacturing plants was improved. Equipment was sized for six commercial-scale plant capacities, ranging from 800 to 10,000 tonnes/yr of anhydrous milk fat. Analysis considers capital investment, annual manufacturing expenses, revenues, sales, and payback time. The equipment scale-up index was .53, which is the usual literature value. For a plant processing 10,000 tonnes/yr of anhydrous milk fat, conversion cost is $.15/kg over a base price of $1.98/kg. Such a plant would have a capital investment of $4.4 million and annual manufacturing costs of $21.1 million. Example selling prices are calculated assuming a desired rate of return of 20% or a payback period of 5 yr, which further adds $.Il/kg to the base price and conversion cost, yielding annual sales of $22.2 million. The economics of the process are attractive, even. though further optimization of operating conditions has not yet been performed, primarily because of the continuous nature of the process, the heat regeneration systems designed, and the large plant capacities considered. Thus, the notion that supercritical processing is expensive may be valid only for batch or semi-continuous systems rather than for continuous large-scale systems such as those studied herein.