Institute for Sanitary Engineering, Water Quality and Solid Waste ...

Waste Water Technology AWT
A 2-stage concept for fermentative hydrogen and
biogas production by means of an innovative gas
treatment
Worldwide, the energy demand is still predominantly
supplied from fossil fuels. Increasing energy consumption,
limited natural resources and global warming, as
a result of the excessive CO 2 emissions connected with
the burning of fossil fuels, require the development of
alternative methods for energy production. Fuel cells
that use hydrogen as a fuel are a promising alternative
for energy production. However, current methods for
hydrogen production are still quite energy-consuming.
For this reason, biological production of hydrogen is
investigated as a possible alternative.
Aim of the project is the production of bio-hydrogen
and biogas by means of an innovative technique for
gas separation (IFK). The process should be carried
out in a two-stage anaerobic fermentation process. As
an alternative, bio-polymers instead of biogas could
be produced. At the first stage the substrate originating
from biological wastewater treatment processes is
transformed by incomplete fermentation to hydrogen.
The end-products of the first incomplete fermentation
can be further fermented at a second stage to produce
biogas or biopolymers. The produced gas of both
stages is treated by means of special ion-exchangers,
which separate CO 2 from the corresponding gas mixture,
at ambient pressure. The upgraded pure hydrogen
can be used as fuel in public traffic while the pure
biogas can be injected into the biogas network. During
the gas-separation process heat is emitted, which
can be utilized for the heating of the fermenters and
contribute to the self-sufficiency of the whole process.
The production of almost pure CO 2 during the regeneration
process of the ion-exchangers is another advantage.
This CO 2 can be returned into the reactor of
the first stage for the reduction of the partial pressure
of hydrogen down to equilibrium concentrations (10 -3
bar – 10 -4 bar) for the improvement of the hydrogen
yield.
Within the scope of lab-scale experiments, various
substrates originating from wastewater treatment will
be tested for their suitability for bio-hydrogen production
and their corresponding end-products for biogas
and biopolymer production. Herewith, the influence of
the boundary conditions (e.g. pH, partial pressure of
hydrogen, required CO 2 quantities for stripping, nutrients,
solids retention time, loading of the fermenters,
substrate composition) on these biological processes
should be investigated. The major aim is the maximisation
of the yields of each process.
Funding:
Bundesministerium für Bildung und Forschung
(BMBF)
Funding Duration:
03/2009 - 02/2012
Project Partner:
Institut für Feuerungs- und Kraftwerkstechnik (IFK),
Universität Stuttgart
EnBW AG
Purolite Deutschland GmbH
RBS wave GmbH
Project Manager:
Prof. Dr.-Ing. H. Steinmetz
Project Coordinator:
Dipl.-Ing. RBM C. Meyer
Contact Person:
Iosif Mariakakis, M.Sc.
Internet:
http://www.iswa.uni-stuttgart.de/awt/en/research_
current.html#hydrogen2
Figure:
Scheme of process
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