RESUMO
Abstract In the present study, the software Aspen Plus® was used to analyse two different systems for CO2 recycle in a SFE process for extraction of more polar compounds using ethanol as co-solvent, the most common co-solvent used due to its environment-friendly nature. The extraction process of β-ecdysone from Brazilian ginseng roots was considered as example in the computational simulations. The first CO2 recycle system, named Recycle A, considered the compression of the CO2 separated in the second flash to the recycle pressure assumed at the first flash tank, its cooling to 25 °C and recirculation, while the second recycle system, named Recycle B, considered the cooling and pumping of the CO2 separated in the second flash, its heating to 25 °C and recirculation. The best techno-economic condition to operate the recycling step would be using Recycle A at 40 bar and 30 °C considering a stand-alone SFE process; and using Recycle B at 40 bar and 40 °C, considering this process in close proximity of a hypothetical sugarcane biorefinery. Therefore, these results suggest that the selection where would be located the SFE plant should be taken into account during the first steps of the process design.
RESUMO
Recently, supercritical fluid extraction (SFE) has been indicated to be utilized as part of a biorefinery, rather than as a stand-alone technology, since besides extracting added value compounds selectively it has been shown to have a positive effect on the downstream processing of biomass. To this extent, this work evaluates economically the encouraging experimental results regarding the use of SFE during annatto seeds valorization. Additionally, other features were discussed such as the benefits of enhancing the bioactive compounds concentration through physical processes and of integrating the proposed annatto seeds biorefinery to a hypothetical sugarcane biorefinery, which produces its essential inputs, e.g., CO2, ethanol, heat and electricity. For this, first, different configurations were modeled and simulated using the commercial simulator Aspen Plus® to determine the mass and energy balances. Next, each configuration was economically assessed using MATLAB. SFE proved to be decisive to the economic feasibility of the proposed annatto seeds-sugarcane biorefinery concept. SFE pretreatment associated with sequential fine particles separation process enabled higher bixin-rich extract production using low-pressure solvent extraction method employing ethanol, meanwhile tocotrienols-rich extract is obtained as a first product. Nevertheless, the economic evaluation showed that increasing tocotrienols-rich extract production has a more pronounced positive impact on the economic viability of the concept.
RESUMO
This study provides a preliminary contribution to the development of an industrial process for the UV/TiO(2) water treatment by introducing a novel support for TiO(2) immobilization. For the following study, Methylene Blue (MB) was chosen as the model dye to evaluate this novel immobilization system. The results showed that TiO(2) immobilized in a Ca-alginate bead retained its photoactivity during all of the experiments and the TiO(2)-gel beads presented good stability in water for maintaining its shape after several uses. When a proportion of 10% (v/v) of these beads was used, the configuration system demonstrated an improved mass transfer and consequently enhanced degradation efficiency. Experiments were also performed using 'recycled' beads. The results showed an increase in the degradation efficiency when the beads were reused, with an eventual 'self-destructive' effect. These studies showed great promise regarding the recyclable reagents with a reduction in waste at no greater cost or reduction in efficiency. Therefore, the potential of TiO(2)-gel beads as a simple and environmentally friendly catalyst for continuous use was developed.