Design and Economic Analysis for Continuous Countercurrent Processing of Milk Fat with Supercritical Carbon Dioxide

¹ Institute of Food Science, and Northeast Dairy Foods Research Center, Cornell University, Ithaca, NY 14853

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 $.11/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.

Key Words: economic analysis • supercritical • carbon dioxide • milk fat

Submitted on February 18, 1993
Accepted on October 18, 1993