Strategic situation, design and simulation of a biorefinery in Andalusia

Abstract

The installation of a biorefinery in the centre of Andalusia, a region located in the south of Spain, has been evaluated in this research study. The biorefinery was designed and dimensioned according to the availability of lignocellulosic biomass waste in this area to ensure a permanent operation. Specifically, different mixtures of forestry, olive and grape pruning, sunflower waste and sawdust has been proposed for their valorization to obtain chemicals such as ethanol, dimethylether (DME), synthesis gas and, eventually, electricity, which entail the social, environmental and economical improvement of this area. The process consisted of an alkaline pre-treatment unit, Kraft pulping process, which separates the incoming lignocellulosic waste to a cellulose-rich pulp and the black liquors containing dissolved lignin. The pulp could be treated through acid hydrolysis, evaporation, adsorption, fermentation and distillation processes, mainly, to obtain ethanol, while the liquor was gasified and converted to DME. The operating conditions for the different process stages were optimized to reduce, as far as possible, the generated by-products. The total ethanol production was 42,700 T y−1, which represents 16.5% of Spanish production. On the other hand, the indirect and direct DME syntheses were evaluated under isothermal and adiabatic conditions. The highest DME production was obtained by using direct DME synthesis developed in an isothermal reactor. A total DME production of 137,850 T y−1 with a purity of 99.99% was obtained. The implementation of this proposal seems to be technological and economically feasible.