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how EFFiCiEnt CAn it bE?
By sales Director, Mr. Bent Have Johnsen, Aalborg engineering A/s
During decades the Danish industry of energy producing equipment
has been pushed for achieving higher and higher goals. the
pressure has come from the shifting governments in order to
release Denmark from import of energy to being independent.
the results have been shown in many ways. these years the most
visible effect has been the renewable energy market. there are
however other technologies which has proven its co2 and emis-
sion reducing capabilities previously.
in 2003, Aalborg engineering was awarded the heat recovery boiler
for the new block 8 on H.c. oerstedsvaerket in copenhagen. the
plant would be a part of a master plan for the complete district
heating system of the capital. Basis for the plant was a gas turbine
(today known as a siemens sgt 600) which was moved from
naestved to the site in copenhagen.
in order to meet the required capacity the gas turbine had to
be equipped with a heat recovery boiler with the possibility of
increasing the production considerably. During the project study
Aalborg engineering worked closely with the plant owner to make
the best technical and feasible solution. the result was a heat
recovery boiler with a high degree of supplementary firing using
natural gas.
in this solution we made it possible to increase the basic gas
turbine load with additional app. 60 Mwt. the parameters were
defined as low pressure steam for the copenhagen district
heating system as well as district heating water. the plant was
defined to have approx 500 annual operating hours. not much
compared to the work carried out and investment made. But
still the installed capacity had to cover for the expected ambi-
ent conditions of the city and to make sure there were sufficient
heat for the consumers.
the plant was installed in an old power plant building. this fact
required extraordinary efforts to avoid making any changes to the
old building which was considered worth preserving. the installation
was made through the basement and access ports just
below roof level. the plan succeeded and today a modern efficient
plant is producing heat for the city of copenhagen.
speaking about efficiency there are some quite interesting operational
features the heat recovery boiler is build for. As mentioned
it was expected to use the installation for approx 500 hours per
year. today, after five years of service the plant has become base
load. that means the plant is scheduled to operate all the time.
Due to the combination of producing power and heat this is the
most feasible installation of the system. the heat recovery boiler
has an efficiency as high as 98 % when the plant is on full gas
turbine and supplementary firing mode.
indeed an achievement which is difficult to speak against even in
a time where fossil fuels in general are considered problematic.
let this be a good example of the climate friendly and prudent
fossil usage.
thAt is
how EFFiCiEnt
CAn it bE!
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