Teknoekonomisk studie för fullskalig produktion av biomassa från mikroalger

Sammanfattning: Microalgae have received a surge in attention in the past decade as a source for renewable energy. They are currently used to produce high-value products but have the potential to produce biofuels such as bioethanol, biodiesel and biohydrogen among others. The present work is an evaluation of the feasibility of a process producing microalgae as a wet biomass paste through modeling of a real process. The production process of microalgal-derived low-value products has yet to be realized due to the low productivity in current culture systems, the high cost of such systems and the high cost of harvesting the microalgal biomass. An accurate and efficient model of this process is key in allowing for scale up to where it can contribute sufficiently to a more sustainable society. The model constructed evaluates the best alternative out of twelve configurations using data supplied by the user. The model is flexible in that it allows for modeling of different microalgae and different scales of production. Genetic engineering of the microalgae is modeled as three different cases: a reduction in the light-harvesting antennae, the expression of a fluorescent protein that by absorbing UV light emits photosynthetically active radiation and a combination of the two. The model is then run for the case relevant to the user. To evaluate the performance of the model and the viability of the modeled process, it was ran for the microalgae P. tricornutum and an annual production demand of 1000 ton wet biomass paste. The break-even price of the biomass was 8.79 Ä for the base case and 5.68 Ä with both cases of genetic engineering of the microalgal cell. The best configuration was found to be a tubular photobioreactor in the cultivation stage with flocculation-sedimentation followed by filtration in the harvesting stage. The model is capable of producing results that are in line with the current research and are thus deemed reasonable. With the level of accuracy that the model presently contains, it is a good representation of the production of microalgal biomass as a whole. However, to be able to draw definitive conclusions, more time and research is required.