Vanja Ugresic

Date of Award


Degree Type


Degree Name

Master of Engineering Science


Chemical and Biochemical Engineering


Dr.-Ing. Markus Spinnler

Second Advisor

Dr. Ajay K. Ray


Disposal of digestate and fermenting remainders from the biogas facilities represents a serious problem. In order to drastically reduce the volume of digestate the principle of thermal concentration could be applied to it.

The goal of the study was to develop an economic and energy efficient digestate concentrating plant on the basis of humidification dehumidification (HD) principles. The advantage of using HD system was the possibility to combine it with the biogas plant that provides the low temperature waste heat necessary to drive the process. The simple, inexpensive process design and mild operating conditions provided further merits for the application of HD towards digestate processing.

Experiments were done on specifically designed experimental test-rig, and a simulation model using Aspen Plus was developed to perform parametric studies. Through the parametric studies, the simulation model was optimized, and it provided the necessary design data for the construction of the first prototype.



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