Biogas upgrading to biomethane - The Biogas: Science, Production and Applications - page 337

. storage capability

. flexibility regarding several utilization paths: electricity (combined with

full utilization of heat); heat (combined with power or in natural gas
burners); vehicle fuel (for natural gas vehicles); and primary product for
the chemicals industry.

Biomethane is thus set to become an important building block of a
renewable-based future energy system.

15.2 Development and overview of biogas upgrading

Biogas upgrading to biomethane has a worldwide history of nearly a
century. For example, in Germany [1], Switzerland and elsewhere [2],
wastewater treatment plants operated sewage gas upgrading plants from the
mid-1930s to the mid-1960s. This biomethane was used mainly for the
provision of vehicle fuel for passenger cars driven by Otto engines [1] and
waste collection trucks [2]. This kind of biomethane provision was
discontinued in the mid-1960s because of discontinuations of preferential
tax treatment, technical developments and cheap oil imports [1].
Nowadays, biogas upgrading is especially focused on Europe and partly
North America. Outside of these two continents, there are only a few plants
in operation. From the start of the 1980s, several projects where biogas has
been upgraded to natural gas quality, have been described.
In Moenchengladbach, Germany, a plant upgrading sewage gas operated
from 1982 to 1996. During this period, around 20 million m 3 of biomethane
(L-gas quality) were injected into the local natural gas grid. As upgrading
technology, a water scrubber with a raw gas capacity of 400m 3 /h was used
[1, 3, 4].
Before 1985, a project in Christchurch, New Zealand, started operation.
In this project, biomethane for utilization as vehicle fuel was produced by a
water scrubber with a capacity of 60m 3 /h [5, 6].
In Stuttgart, Germany, sewage gas was upgraded from 1986 to 1993.
Roughly 5 millionm 3 biomethane (H-gas quality) were injected into the local
natural gas grid. The upgrading plant (chemical scrubber using mono-
ethanolamine (MEA)) had a capacity of 400m 3 /h of raw sewage gas [3].
In the USA, the first biogas upgrading projects also began in the 1980s.
Four separate projects in Staten Island (1981), Renton (1984), Cincinnati
(1986) and Houston (1986) with an overall raw gas upgrading capacity of
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30,000m 3 /h produced biomethane from landfill and sewage gas for grid
injection. As upgrading technologies, two Selexol ® scrubbers, one water
scrubber and one pressure swing adsorption (PSA) were used [7].
In The Netherlands, several landfill gas upgrading projects were
implemented from 1987 to 1991. All the projects injected biomethane into