Ammonia separation technology for biogas plant using membrane contactor

presentation, poster

English

Biogas plants are a significant source of renewable electricity and heat energy and produce a large amount of digestate as a by-product of anaerobic digestion. The digestate can be separated into two phases: a solid phase (separate) and a liquid phase (fugate). The fugate is a high-quality fertilizer, but there is a problem with its high ammonia nitrogen concentration, which is harmful and toxic to the environment. Nowadays, laws are increasingly limiting the amount of ammonia nitrogen allowed in agricultural fertilizers, so the improvement of separation processes for ammonia removal take place. Our work deals with development of ammonia separation technology from fugate produced by biogas plant. The technology is based on desorption of ammonia in membrane contactor into acidic solution. The laboratory-scale contactor was assembled in the first phase of this project, and pilot-scale experiments were conducted on this contactor using model solutions and fugate containing ammonia nitrogen. Then the process optimization took place, and the ammonia removal efficiency and mass transfer coefficient were calculated based on the results of the experiments. The knowledge gained from laboratory experiments study was used to construct a pilot plant on the premises of the biogas plant. Final real conditions experiments were made on this device and the best results were obtained in combination of increased temperature and pH. The highest reached ammonia removal efficiency was 40 % in the time of 150 minutes. This work's main output is a functional verified technology with the possibility of batch and continuous operation modes.

membrane contactor, ammonia separation, fugate, mass transfer, biogas plant

LINDOVSKÝ, J.; SVĚRÁK, T.; KALIVODA, J.; KRIŠTOF, O.

15. 5. 2023