ANAEROBIC DIGESTION OF EFFLUENTS AND SUBPRODUCTS FROM A BIOREFINERY MANUFACTURY FOR BIOGAS PRODUCTION: CONTINUOUS AND BATCH OPERATION

11/28/2024

The growing demand for renewable energy and waste valorization has intensified interest in biogas production through anaerobic digestion (AD). This thesis investigates the anaerobic digestion of industrial effluents and byproducts from a biorefinery for biogas production, focusing on both continuous and batch operations. A comprehensive experimental study was conducted to analyze the operational parameters, chemical oxygen demand (COD) removal efficiencies, and biomethane production of various effluent mixtures. Continuous experiments utilized four reactors operating at mesophilic temperatures with different hydraulic retention times (HRT). Results showed significant variability in COD removal, with reactors R1 and R2 achieving stable removal efficiencies of around 50%, while R3 and R4 showed fluctuations due to substrate overloading and occasional operational issues. Biogas production correlated strongly with COD reduction, confirming the process's potential for energy recovery. Batch experiments explored the biomethane potential (BMP) of various effluent mixtures, including substrates rich in glycerin, soapstock, and bagasse. Among the batch reactors, Y1 and Y3 outperformed others in biomethane yield, with Y1 achieving 81% methane content. Substrate composition and inoculum-to-substrate ratio significantly influenced biogas yields, with optimal results observed in reactors with balanced nutrient availability and inoculum concentrations. The study concludes that AD is a viable method for waste valorization in biorefineries, offering potential for bioenergy recovery. The findings provide valuable insights into process optimization for industrial scale applications and pave the way for future work focused on reactor scaling and long-term process stability.

Authors in the community:

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  P

  Palash Gupta

  ist1109202

Supervisors of this institution:

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  F

  Francisco Manuel Da Silva Lemos

  ist12081

mechanical-engineering - Mechanical engineering

por - Portuguese

Instituto Superior Técnico