No abstract

No abstract

No abstract

Rigorous thermodynamic modeling, simulation, and optimization of the supercritical fractionation of EPA and DHA esters is presented. These valuable products are obtained from complex mixtures of fish oil fatty acid alkyl esters by high-pressure fractionation with supercritical carbon dioxide. A group contribution equation of state (GC-EOS) that provides reliable phase equilibrium and solubility predictions is used to support the process simulation. A correlation has been developed for the estimation of a thermodynamic model parameter:  the fish oil esters hard-sphere diameter. The capability of the group contribution equation of state is confirmed by a detailed comparison of predictions with experimental data. Rigorous simulation models for process units have been formulated within a nonlinear optimization model to maximize EPA and DHA esters recovery and purity from several natural fish oil mixtures with supercritical extraction.

No abstract

In this work we propose an MILP multiperiod formulation for the optimal design and planning of the Argentinean biodiesel supply chain, considering land competition and alternative raw materials. The country is divided into twenty three regions, each one including existing crops, oil and biodiesel plants and potential ones. The model includes intermediate and final products, i.e., seed, flour, pellets and expellers, oil, pure and blending biodiesel and glycerol. Crop fields, storage and production plants, as well as distribution centers for internal and external markets are also represented. We consider the possibility of sowing energetic crops, such as Jatropha curcas, in marginal areas. The time horizon is of seven years, divided into 84 periods. The mathematical model has been implemented in GAMS providing a powerful decision-making tool that can be applied to other regions or countries by adjusting specific data.

No abstract

In this work, we have formulated a series of nonlinear programming models based on first principles and rigorous thermodynamic predictions, to perform economic evaluation for different scheme alternatives in supercritical methanol transesterification for biodiesel production. The model includes thermodynamic predictions with a group contribution equation of state that have been favorably compared, in this work, to the available experimental data for the different mixtures at different operating conditions. The resulting nonlinear programming problem for cost minimization has been solved with a successive quadratic programming algorithm. Numerical results indicate that the use of a heat pump within the noncatalytic biodiesel production scheme significantly reduces operating costs, making this technology economically competitive as compared to conventional ones.