Supercritical CO2 extraction of macadamia nut oil was carried out in a flow apparatus at the following operational conditions: pressures of 10, 15 and 18 MPa; and temperatures of 313 and 353K; a volumetric flow of 1.64 x 10-7 m³.s-1 was used for one hour in each experiment. The efficiency of the extraction process showed to be low. The behaviors of the extraction curves were very similar at all temperatures and the best efficiency value was obtained at 10 MPa. Chromatographic analysis demonstrated the ability of supercritical CO2 to remove some of the main components of the oil: myristic (C14:0), palmitic (C16:0), oleic (C18:1) and linoleic (C18:2) acids, and that higher pressures favoured the removal of lighter components. The extraction process was represented by a simple model based on Langmuir Isotherm, showing a good data fitting.

Supercritical CO2 extraction of the pigments from Bixa orellana seeds was carried out in a flow apparatus at a pressure of 200 bar and a temperature of 40 ºC at two fluid flow rates (0.67g/min and 1.12g/min). The efficiency of the extraction was low (only about 1% of the pigment was extracted). The increase in flow rate led to a decrease in pigment recovery. A large increase in recovery (from 1% to 45%) was achieved using supercritical carbon dioxide with 5 mol % ethanol as extraction fluid at pressures of 200 and 300 bar and temperatures of 40 and 60 ºC. Although the increase in temperature and pressure led to an increase in recovery, the changes in flow rate did not seem to affect it. Furthermore, two plug flow models were applied to describe the supercritical extraction of the pigments from annatto seeds. Mass transfer coefficients were determined and compared well with those obtained by other researchers with similar models for the supercritical extraction of solutes from plant materials.

The synthesis and analysis of heat exchanger networks are issues of great industrial interest due to the possibilities of decreasing plant costs, through the reduction of the utilities consumption and/or the number of equipments, in a grassroot design or retrofitting an existent network. The present paper explores a new design algorithm based on the Total Annual Cost (TAC) optimization for a thermal equipment, with mean tubeside and shellside flow velocities constraints, studying also the influence of pumping cost in the network’s final cost.