Technical Session 21: Spent Grains Session
Benjamin Haeffner, TU München - Chair of Process Engineering of Disperse Systems , Weihenstephan
Co-author(s): Jens Voigt and Karl Sommer, TU München, Chair of Process Engineering of Disperse Systems, Weihenstephan, Germany
ABSTRACT: Energy from waste materials of the brewing
process is playing a rising role in breweries. Today and in the future,
it will become very difficult for the brewing industry to dispose of
their waste materials. Due to new regulations and higher standards for
waste treatment, producers are being forced to find new methods of cost
neutral discharge of their biological waste that also meet regulatory
requirements. Brewery wastes with a high content of cellulose,
ligno-cellulose, and hemi-cellulose, like spent grains, have a high
potential to become a key factor in cost neutral brewery waste discharge
if you know how to gain access to this stored energy. Thus, the use of
spent grains as an energy source through anaerobic fermentation is a
good solution. The key to solving this problem is the combination of two
well-known unit operations: milling and fermentation These application
areas are focused on at the Chair of Process Engineering of Disperse
Systems. A current research project is biogas fermentation in a
multi-step solid bed process to optimize the dwell-time, which is
supported by AiF (German Federation of Industrial Research
Associations). The grinding process is performed with an agitator ball
mill. This task is achieved by changing the parameters of the milling
process to reach the highest possible energy utilization. Another
advantage is an increased area of particles, resulting in a higher
degree of bioavailability, which is expected to have a positive effect
on the degradation rate and residence time distribution. In the
fermentation process a fixed bed reactor containing filling materials is
used, increasing the contact surface between substrate and bacteria and
leading to a higher fermentation rate. With these improvements the
hydraulic retention time of the reactor can be reduced without changing
the performance parameters (biogas yield, degree of degradation). With
the results from the work packages, we can achieve the best energy
efficiency of the overall process.
Benjamin Haeffner was born
in 1979. He apprenticed as a specialist in food technology at the Döhler
company. He received a diploma engineer (M.S.) degree in food and
beverage technology from TU München-Weihenstephan, Germany, in 2006.
After that he started his career at the Chair of Process Engineering of
Disperse Systems at TU München as a technical engineer in wet/dry
grinding and fermentation processes. He is an expert in comminution of
organic materials and gives lectures on engineering science fundamentals
of apparatus. Since 2011 he has been working as a Ph.D. student at the
Chair of Process Engineering of Disperse Systems and has edited his own
project (“Biogasfermentation in Multi-step Solid Bed Process as
Optimization for Dwell-Time”), which is supported by the German
Federation of Industrial Research Associations (AiF) and the Research
Group of the German Food Industry (FEI).
VIEW PRESENTATION 71
