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

Fractionation of anhydrous milk fat using supercritical CO2 provides v arious fractions of different physicochemical and functional propertie s 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 manufac turing plants was improved. Equipment was sized for six commercial-sca le 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 i ndex was .53, which is the usual literature value. For a plant process ing 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 inve stment of $4.4 million and annual manufacturing costs of $21.1 million . Example selling prices are calculated assuming a desired rate of ret urn 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 mil lion. The economics of the process are attractive, even. though furthe r optimization of operating conditions has not yet been performed, pri marily because of the continuous nature of the process, the heat regen eration systems designed, and the large plant capacities considered. T hus, the notion that supercritical processing is expensive may be vali d only for batch or semi-continuous systems rather than for continuous large-scale systems such as those studied herein.