OPTIMAL DESIGN OF ALGAE-BASED BIOREFINERIES USING CO_2 FROM DIFFERENT INDUSTRIAL FACILITIES

摘要

This work proposes an optimization approach for the carbon dioxide sequestration fromdifferent industrial facilities to yield an algae-based biorefinery. The proposed approach isbased on a distributed system to account for the economies of scale and it involves the siteselection for the processing facilities as well as the transportation cost. Additionally, the modelconsiders the optimization for the technologies used in each facility for the CO_2 sequestration,for the algae growth, harvesting, lipid extraction, and different technologies to yield severalproducts like biodiesel, methane, ethanol, between others, depending on the customerdemand. The proposed approach considers the mass exchange between different industrialfacilities, because the algae from one plant can be used to produce products used in thesame or in a different plant. The optimization model considers the maximization for the totalnet profit, which includes the sales of products plus the tax credit for reduction of CO_2emissions minus the capital and operational costs for the different processing stages minusthe overall transportation costs associated to the system. The constraints for the modelinclude the mass balances for the system, design and operational constraints for theprocessing units and constraints for the demands for the products. The proposed model is amixed integer non linear programming model and this was coded in the software GAMS.Finally, two case studies from Mexico were analyzed and the results show several economicand environmental benefits simultaneously.