Utilization of digestate in a convective hot air dryer with integrated nitrogen recovery

Publikations-Art

Zeitschriftenbeitrag (peer-reviewed)

Autoren

Awiszus, S; Meissner, K; Reyer, S; Müller, J

Erscheinungsjahr

2018

Veröffentlicht in

Landtechnik

Band/Volume

73/4

DOI

10.15150/lt.2018.3187

Seite (von - bis)

106-114

Schlagworte

Ammonia emissions

NH3 emissions from agricultural production and from digestate represent a significant part of total nitrogen emissions and can be significantly reduced by adapting the respective process technology. A recovery rate of more than 90 % of the released NH3 could be detected in a twobelt dryer with an exhaust air scrubber, which was operated to investigate the drying parameters of dewatered digestate. The specific thermal energy consumption of the dryer ranged
between 0.89 and 1.04 kWh kg-1 depending on the throughput and the temperature of the digestate. Drying resulted in a loss of about 50 % of total-N in the substrate, which is equivalent to about 80 % of the NH4-N content. NH3 concentrations of 10.8 mg m-3 were measured in the purified exhaust air. This corresponds to a release into the environment of 25.5 g h-1. The NH3 release from the digestate was only dependent on the amount of digestate and was
not influenced by the drying temperature.