Title:
Evaluation of Ultrafiltration Performance of Anaerobic Digestate form Thin Stillage after Centrifugation
Author(s):
Meixner, K., Drosg, B., Loderer, C., Bochmann, G., Valkova, T., Svardal, K., Fuchs, W.
Document(s):
Paper
Abstract:
At a grain bioethanol plant thin stillage is one of the most interesting stillage fractions for energy recovery by biogas production. However, by anaerobic digestion an effluent digestate is produced for which it is necessary to establish suitable utilisation concepts. Digestate treatment by ultrafiltration can be a viable solution to produce process water or a liquid which can be further purified. This study evaluates the performance of membrane filtration by a ceramic ultrafiltration membrane at laboratory scale. As feed digestate supernatant from thin stillage after a nozzle separator was used. In addition, the effect on filtration performance by adding precipitating agents (FeCl3, CaCO3) to separation was evaluated. First, optimal filtration parameters were evaluated by using different CFV rates 2, 3, 4 and 6 m/s and TMP between 0.5 and 3 bar. With the optimal parameters (CFV: 6 m/s; TMP: 0.8 bar) continuous filtration experiments were carried out. They showed that by adding precipitating agents during the centrifugation step, the flux rates could at least be doubled, from approx. -1 -1 40 L•m -²•hto approx. 80 L•m -²•h. In addition, the experiments showed that a solid-liquid separation is a crucial prerequisite for a well-functioning ultrafiltration step for thin stillage digestate. In the bioethanol process permeate can be – at least partially – reused as process water. Moreover, artificial nitrogen sources in the bioethanol production can be substituted by the recycled ammonia.
Keywords:
anaerobic digestion, bioethanol, digestate, filtration
Topic:
R&D on Biomass Conversion Technologies for Heating, Electricity and Chemicals
Subtopic:
Anaerobic digestion for biogas production
Event:
20th European Biomass Conference and Exhibition
Session:
2DV.3.11
Pages:
1424 - 1428
ISBN:
978-88-89407-54-7
Paper DOI:
10.5071/20thEUBCE2012-2DV.3.11
Price:
FREE
