Sustainability Session
Ruslan Hofmann, VLB Berlin e.v., Berlin, Germany
Co-author(s): Roland Folz, VLB Berlin e.v., Berlin, Germany
ABSTRACT: After harvest green hops show water contents of
70–80%, which must be reduced to approximately 10%. During the hop
kilning process fresh air is heated to approximately 65°C. The exhaust
air has temperatures of 28–35°C and a relative humidity of up to 100%.
In conventional hop kilning systems the air is released directly into
the atmosphere. With the help of the company WOLF Anlagen-Technik GmbH
& Co. KG a pilot heat exchange system was integrated into an
industrial size hop kiln in the Hallertau region of Germany. The goal of
the project was to decrease the consumption of fossil resources for
heating and to recover volatile hop components from the exhaust air of
the hop kiln. Via suction pipes the exhaust air may be conveyed to the
heat exchanger. One pipe was equipped with a carbon filter to trap
volatile hop components from the exhaust air of the hop kiln. The carbon
filter material was analyzed using gas chromatography. The heat
exchanging process generated condensate, which was analyzed in the same
way. Hop oils were detected in the condensate as well as the filter
material. At least 0.25 mg of hop oils per hour and m3 of
exhaust air could be recovered. The exhaust air had a mean temperature
of 31.3°C. Post heat exchange the air left the HE unit with a mean
temperature of 23.2°C. In the mean, fresh air was heated from 15.0 to
24.4°C. Heat recovery resulted in an efficiency of approx. 50%. These
figures led to a calculated 38 kW/hr energy recovery or a reduced energy
consumption of 20.8%. According to the current price level (0.8 euro/L
fuel oil) a theoretical saving of approx. 200 euro/day the kiln is
running was achieved.
Ruslan Hofmann received his
Diplom-Ingenieur (comparable to master of engineering) degree in brewing
technology from Technische Universität Berlin, Germany. Before studying
he worked for the Berliner Bürgerbräu Brauerei in Berlin. Since 2008 he
has been employed at the research and educational institute Versuchs-
und Lehranstalt für Brauerei (VLB) in Berlin e.V., where he worked in
the packaging laboratory for nearly two years and afterward joined the
Department for Brewing & Beverage Science and Applications. Ruslan
is responsible for research projects in the field of packaging, raw
materials, and flavor stability.
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