To date the management of digestate is a crucial task for anaerobic digestion process. In the present work a strategy for digestate management is thermodynamically analyzed by a commercial software for process simulation called CHEMCAD®. Pyrolysis of digestate is simulated by a minimization of the free Gibbs energy. The sequestration of the carbon dioxide (CO2) released by the pyrolysis is investigated by the addition of calcium oxide, in order to reduce CO2 emissions. The effect of the pyrolysis temperature between 400–900 ℃ and of the CaO/digestate mass ratio between 0–0.5 was discussed, as well. The CHEMCAD application allowed to investigate the chemisorption behaviour by focusing on the temperature-dependent CO2 sorption trends in relation to different values of the CaO mass ratio. Temperature below 650 ℃ should be considered for CO2 sorption by CaO. CO2 molar fraction below 10% was obtained for temperature below 450 ℃ and CaO/digestate mass ratio higher than 0.4.
Thermodynamic Analysis of Digestate Pyrolysis Coupled with CO2 Sorption
Freda C.
2023-01-01
Abstract
To date the management of digestate is a crucial task for anaerobic digestion process. In the present work a strategy for digestate management is thermodynamically analyzed by a commercial software for process simulation called CHEMCAD®. Pyrolysis of digestate is simulated by a minimization of the free Gibbs energy. The sequestration of the carbon dioxide (CO2) released by the pyrolysis is investigated by the addition of calcium oxide, in order to reduce CO2 emissions. The effect of the pyrolysis temperature between 400–900 ℃ and of the CaO/digestate mass ratio between 0–0.5 was discussed, as well. The CHEMCAD application allowed to investigate the chemisorption behaviour by focusing on the temperature-dependent CO2 sorption trends in relation to different values of the CaO mass ratio. Temperature below 650 ℃ should be considered for CO2 sorption by CaO. CO2 molar fraction below 10% was obtained for temperature below 450 ℃ and CaO/digestate mass ratio higher than 0.4.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
