University of Twente Student Theses
Techno-economic feasibility analysis of a second-generation ethanol plant using the solid part of digestate as feedstock
Hilgert, J.E. (2019) Techno-economic feasibility analysis of a second-generation ethanol plant using the solid part of digestate as feedstock.
|
PDF
6MB |
| Abstract: | Second-generation ethanol is a technology that has been investigated to solve the dilemma of food vs. fuel that the development of biofuels is facing. However, the large scale production of biofuels presents some challenges. The costs to produce it and the process are very dependent on the feedstock. Process modeling can help to verify where the techno-economic bottlenecks of the production process are. This work is an evaluation of the attempt to produce second-generation ethanol from the solid part of the digestate from the anaerobic digestion process of manure. This work presents a detailed process model with the feedstock handling, pretreatment, enzymatic hydrolysis, fermentation, separation, and purification of ethanol, steam and power generation, and wastewater treatment and simulates this process in SuperPro Designer, in two scenarios: grass-root plant and an optimistic version using the facilities available at Twence B.V. Projected ethanol yields were 123,02 l/dry metric ton biomass using dilute alkali as the pretreatment technology. The feedstock is considered a source of revenue in the optimistic scenario and free of costs for the grass-root scenario, the cellulase cost is e0,18 per liter of ethanol produced, and sodium hydroxide cost is e0,59. The plant projected can process 150.000 metric tons of feedstock per year, and the capital cost reached 55.4 Mefor the grass-root scenario and 33.7 Mefor the optimistic one. The ethanol production cost is e1,42 and 2,51 per liter in the optimistic scenario and the grass-root scenario, respectively. The water consumption of the plant reaches 24.1l of water per kg of ethanol produced. The comparison with other projects that used lignocellulosic feedstock to produce ethanol showed that the cost of production is higher when the solid part of the digestate used as feedstock. The reasons for that are the lower content of carbohydrates and the losses of sugars during the pretreatment process. With that, other alternatives may try to mix the solid part of the digestate with another feedstock richer in carbohydrates, to investigate the effects of other pretreatment technologies or to explore the possibility to integrate the anaerobic digestion process with pyrolysis to increase the production of biogas. |
| Item Type: | Essay (Master) |
| Faculty: | ET: Engineering Technology |
| Programme: | Sustainable Energy Technology MSc (60443) |
| Link to this item: | https://purl.utwente.nl/essays/97701 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
Show download statistics for this publication
Show download statistics for this publicationRepository Staff Only: item control page