New proposal for extracting rosemary compounds: Process intensification and economic evaluation

Abstract

This paper brings forward techno-economic results of a study developed with rosemary. Process intensification was applied for obtaining two fractions of bioactive compounds: one fraction rich in volatile oil and other fraction rich in non-volatile extract. Terpenoids as 1,8-cineole and camphor were obtained by supercritical CO2 extraction (SFE-CO2). Afterwards, phenolic compounds as rosmarinic acid and carnosic acid were obtained by pressurized water extraction (PWE). We performed SFE-CO2 and PWE in the same multipurpose equipment without unloading the bed. Extraction yields and composition of each extract fraction were evaluated. We obtained approximately 2.5wt.% of a fraction rich in volatile oil at 40°C, 30MPa and solvent mass to feed mass (S/F) ratio of 2.5g CO2/g rosemary. Likewise, we obtained approximately 18.6wt.% of a fraction rich in non-volatile extract at continuous temperature increase of 1.1°C/min (from 40 °C to 172°C), 10 MPa and S/F ratio of 9.5g water/g rosemary. We simulated costs of manufacturing of extracts obtained by SFE-CO2 in three productive plants containing 2 vessels of 10L, 50L and 100L. The influence of bed geometry was considered into the simulation model, whereas the bed height (HB) to bed diameter (DB) ratios were: HB1/DB1=7.1 and HB2/DB2=2.7. We simulated the productivity of extracts and operating costs for an industrial plant containing 2 vessels of 100L using the process intensification performed in this paper (SFE-CO2+PWE). The proposal is promising and can encourage industrial application, because the higher use of the vegetal matrix for obtaining diversified bioactive compounds can reduce 28% of the annual production costs of SFE-CO2+PWE processes whether comparing with SFE-CO2 process alone.