Environmental Engineering Reference
In-Depth Information
which upgrading technology is used. However, some impurities are also
harmful to the upgrading process and the impurities have to be removed
before upgrading takes place. For example, for some upgrading processes
(PSA, chemical scrubbers and cryogenic upgrading), it is recommended that
hydrogen sulphide be removed before upgrading.
14.5 Conclusion and future trends
Increasing biogas production by digesting more of the available substrates is
a promising way of increasing the share of renewable energy in society. The
increase could come from the digestion of various types of substrates,
including homogeneous materials such as manure and energy crops and
mixed materials such as segregated household waste. The substrates used
will affect the composition of biogas which, together with the utilisation
method, will determine the need for cleaning of the biogas. Manure is an
often unused potential substrate for biogas production in many countries.
However, manure has a low dry matter content and contains a lot of water,
so it is not economical or environmentally sound to transport it over long
distances. For this reason, manure digestion would have to take place in
small-scale digesters. This could lead to a potential for development of
simple cleaning methods adjusted for small-scale applications. Large
volumes of landfill gas are still produced in many countries. Utilisation of
more landfill gas could, on the other hand, lead to the development of more
advanced and large-scale cleaning methods.
Biogas can be utilised in different ways and it is becoming more and more
important to also utilise the heat when power is produced. Increasing
amounts of biogas are also being used as transport fuel or for injection to
the grid and these utilisation paths demand a higher quality of gas.
14.6 Sources of further information and advice
Conestoga-Rovers & Associates (2007) 'Biogas treatment, state-of-the-art review'.
Report for Natural Resources Canada. CRA, Richmond, BC, Canada.
Marcogaz (2006) 'Injection of gases from non-conventional sources into gas networks'.
Marcogaz, Brussels, Belgium.
Persson M, Jo¨ nsson O and Wellinger A (2007) 'Biogas upgrading to vehicle fuel
standards and grid injection'. See www.iea-biogas-net/_content/publications/
publications.php [Accessed 14 October 2012].
Petersson A and Wellinger A (2009) 'Biogas upgrading technologies - developments
and
￿ ￿ ￿ ￿ ￿ ￿
innovations'.
See
www.iea-biogas-net/_download/public-task
37/
upgrading_12_low_final.pdf [Accessed 14 October 2012].
Rasi S (2009) Biogas composition and upgrading to biomethane. Jyva¨skyla¨ Studies in
Biological and Environmental Science, 202.
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