Conference article

Industrial biogas plants often do not operate in their optimum. To investigate limits of anaerobic digestion processes experiments are necessary. Economically it would be feasible to perform these tests at laboratory scale; if the tests could be transferred to industrial scale. This work presents a preliminary study; in which two different scales of laboratory digesters are compared and reproducibility of tests is investigated. Therefore; three identical glass digesters with a liquid volume of up to 22 liter and a steel-digester with a liquid volume of 390 liter were used. All digesters were started up with digestate from an industrial biogas plant; were fed with cow manure and corn cob mix; and were operated at the same process parameters like temperature; organic loading rate and retention time. Gas volumes were measured continuously. Twice a day the composition of the biogas was analyzed. Dry matter and volatile solids were quantified once a week. The presented data show a good reproducibility between biogas plants of the same scale. The transferability to a bigger scale is in an acceptable range; but depending on the organic loading rate the deviation between the different scales varies.

biogas plant; laboratory scale; comparison; reproducibility; transferability