Optimization of conventional batch distillation of anaerobic digestate to isolate ammonium bicarbonate considering the well-known behavior of the non-ideal mixture ethanol-water

Moure Abelenda, Alejandro and Vaisakh, Yesodharan and Aiouache, Farid and Pastora, Pastora (2024) Optimization of conventional batch distillation of anaerobic digestate to isolate ammonium bicarbonate considering the well-known behavior of the non-ideal mixture ethanol-water. In: European Biomass Conference and Exhibition Proceedings, 32nd EUBCE-2024 :. EUBCE . EUBCE, pp. 442-449. ISBN 9788889407240

Abstract

The anaerobic digestate is a byproduct of biogas production and it is suitable for being use as fertilizer. Ammonia and carbon dioxide provide the anaerobic digestate with buffer capacity and these compounds are responsible for the regulation of the pH of this soil organic amendment. The present investigation implied experimental and theoretical data collection to assess the feasibility of isolating ammonium bicarbonate from a complex organic matrix with 95 % moisture, by a conventional distillation procedure. The anaerobic digestate is a complex blend and a similar behavior was expected to that of other non-ideal mixtures, such as the ethanol-water. In addition to the classical batch distillation setup to handle the anaerobic digestate, the distillation column with the mixture ethanol-water was used to model the relations between heating power, boil-up rate, reflux ratio, and separation efficiency. Equilibrium data retrieved from Aspen Plus® v12 and McCabe-Thiele methods were successfully applied to determine the minimum number of stages to isolate ammonium bicarbonate and ethanol in their respective aqueous solutions of non-ideal mixtures. In the case of the aqueous solution including ammonia and carbon dioxide, the optimization of the dose of antifoam was required for successfully perform the operation, due to excessive foam formation.