A novel thermo-mechanical process for the production of biofuels from microalgae

The world energy demand is expected to grow significantly resulting in a further growth of annual C02 release. To solve these problems, a lot of efforts are put in the development of renewable energy technologies. The share of biofuels for transportation applications is expected to triple over the coming two decades. However, these biofuels have to be produced in a sustainable manner and should be economically viable. A possible solution can be found in producing biodiesel from microalgae, because of its high production rate per acre, high lipids content and the possibility of closing the C02 and mineral cycle.

Nevertheless biodiesel from microalgae has some challenges to be tackled. The first challenge is to lower the high energy demand for dewatering of the algae. The second challenge is to lower the high energy demand of the oil extraction process and to increase the oil yield. For this purpose a novel thermomechanical process has been developed. This process offers the opportunity to break and pretreat the microalgae structure. A proof-of-principle is given via batch experiments.

The main goal of this assignment was to design and build an experimental setup for continuous

pretreatment of microalgae. Experiments were conducted to investigate if the cells were broken. Then non-thermal dewatering and oil extraction tests were carried out to investigate the efficiency of the drying and extraction of the broken cells. Experiments in both the batch and continuous setup resulted in broken cells of the microalgae showing that the new process works. Using the dewatering combination of centrifuge and pressing after the thermo-mechanical treatment of the microalgae, it was found that the drying efficiency significantly improved, from 49 to 82 wt% dry biomass. Also, the oil yield from the microalgae improved.

Finally, a techno-economic feasibility study has shown that this novel thermo-mechanical process has a beneficial effect on the biofuel production from microalgae.