ATAC i system - Energimyndigheten

Biomass and Natural Gas. Increased Energy Utilization with the
help of Modern Gas Turbine Technology.
(Biobränsle och Naturgas. Ökad Energieffektivitet i
Omvandlingen med hjälp av Modern Gasturbinteknik)
Projekt nr: P 12477-1
Projektledare: Prof. Torsten H. Fransson
Projektdeltagare: Adj.Prof. Laszlo Hunyadi (25%), supervisor
Prof. Jinyue Yan (5%), asst. supervisor
Miroslav Petrov (100%), doktorand
Projektets varaktighet: 2001-10-01 till 2002-03-31
Beviljade medel: 1 058 000 SEK
Referensgrupp: Thomas Stenhede (Wärtsilä Sweden AB), fadder,
Corfitz Norén (Svenskt Gastekniskt Center AB), Eddie
Johansson (Enköpings Värmeverk/ENA Kraft AB), Marie
Anheden (Vattenfall Utveckling AB), Jinyue Yan (KTH/KET),
Andrew Martin (KTH/EGI), Laszlo Hunyadi (KTH/EGI)
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Projektbeskrivning (Project description):
Utilization of biofuels for electric power generation with conventional steam Rankine
cycles in small-scale applications gives comparatively poor electric efficiencies due to
intrinsic disadvantages of the simple steam cycle, some specific properties of the biomass fuel
and various investment restrictions. On the other hand, modern gas turbines and internal
combustion engines fired with natural gas have comparatively low installation costs, good
efficiency characteristics and low maintenance requirements. If a thermal connection of any
kind is established between a high-grade-fuel fired topping cycle and low-grade-fuel fired
bottoming cycle, a new type of combined cycle (“hybrid” cycle) is realized. The combination
of these two fuels in a single power unit offers many advantages. Part of the overall energy
input occurs in the topping engine, while the other part of the energy input to the overall cycle
occurs in the bottoming boiler in the form of solid fuel. The efficiencies achievable by such
hybrid configurations may prove to be higher than the average efficiency of a combination of
two separate units (one pure combined cycle based on the topping engine and one simple
cycle unit based on the bottoming cycle), burning separate fuels at the given fuel energy input
ratio. These efficiency improvements are achieved without the use of sophisticated or risky
technology. Cost savings may also take place, especially when comparing two separate units
to one hybrid unit utilizing the same fuel mix in small scales.
The basic idea of hybrid dual-fuel combined cycles is not new. Such power plants are
already in service in several countries, and new ones are being installed either as newly
designed units or as repowered old steam boilers, converted into hybrid cycles.
Interest in such cycles (of all scales) is steadily growing worldwide. There is a need for
a considerable amount of work to be done on cycle analysis and cycle configuration modeling
for finding optimum efficiency gain and effects of fuel properties, fuel input ratio and partload
performance. This applies especially to utilization of biomass as fuel for the bottoming
cycle in small scales.