(341a) Developing of Heat Integration Techniques in a Biorefinery for the Sustainable Production of Biodiesel and Succinic Acid

Recently, the concept of integrated biorefineries for the production of biofuels and chemicals is becoming very attractive as humanity searches for different methods to reduce dependency on petroleum. The major reason why there is a very small number of applications of this concept so far, is the elevated cost of the feedstocks and/or the processing technologies of biomass. Biofuel industry can become more economic efficient if it is upgraded to integrated biorefineries (Vlysidis et al., 2011). Techniques which are originally implemented in petroleum refineries, like heat integration (Smith R., 2005), need to be applied to biorefineries in order to improve their sustainability.

In this work, heat integration techniques are developed on a biodiesel biorefinery that co-produces bio-succinic acid. The latter is produced by microbial fermentation from glycerol, the main by-product of the biodiesel industry (Vlysidis et al., 2011). Succinic acid can be used as a building block for the production of many specialty and commodity chemicals and it is considered to be one of the top value added chemicals (Bozell J. J. and Petersen G. R., 2010). Industrial biotechnology, like the succinic acid production, contains processes that offer large energy recovery potentials such as the sterilization and the downstream recovery units. Here, the initial heat exchange network (HEN) is being optimized in terms of maximum energy recovery and minimum total annualized cost by using stochastic optimization methodologies. New HENs are designed and compared with the initial scheme in terms of energy recovery and total cost. The acquired environmental benefits (e.g. decrease of CO₂emissions due to the energy recovery) for each case are also assessed and compared with the primary process. Finally, a sensitivity analysis is carried out for the lifespan of the plant and the interest rate which were originally set to 20 years and 7%, respectively.

Bozell J. J., Petersen G. R., (2010) Technology development for the production of biobased products from biorefinery carbohydrates-the US Department of Energy's "Top 10" revisited. Green Chemistry, 12,539-554.

Smith R., (2005). Chemical Process Design and Integration. Wiley.

Vlysidis A., Binns M., Webb C. and Theodoropoulos C., (2011), A techno-economic analysis of biodiesel biorefineries: Assessment of integrated designs for the co-production of fuels and chemicals, Energy, 36, 4671-4683.