Energy valorization via gasification of the solid residue (digestate) collected in a process of anaerobic digestion (AD) of blended fermentable feedstocks was considered. A rotary kiln reactor was adopted to collect data on the process performances when CO2, steam and mixes of them, were used as gasifying agents. Preliminary experimental campaigns were carried out at 800 °C by using a dried digestate having 64 %-wt volatile matter, 10 %- wt fixed carbon and 26 %-wt ash. Based on the total amount of supplied digestate, at the considered operating conditions, feedstock conversions in the range 59-63 %-wt, were achieved. By using the experimental data (i.e. amount of final residue, yield and heating values of the producer gas) in a simulation model of the gasification process, mass and energy balances were estimated. Among the different process conditions considered, the digestate gasification with preferable, although preliminary, operating conditions resulted that one carried out using only CO2at a CO2/Feedstock ratio around 0.26 by weight. At this operating conditions, for the cold gas efficiency and the producer gas fraction to be used for covering the heat duty at the rotary kiln, values of 69 % and 28 % were respectively estimated. In all other considered conditions, the estimated values were found lower. Chance for process improvements are however predictable.
|Publication status||Published - 1 Jun 2017|
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science
- Renewable Energy, Sustainability and the Environment
- Waste Management and Disposal
Nanna, F., Villone, A., Freda, C., Barisano, D., Agostini, R., Braccio, G., Cornacchia, G., & Brandani, S. (2017). Gasification of anaerobic digestate from mix of biomass residues, manures and MSW to combined heat and power production.