Old boilers to profitable use with local biofuels

Conference · Wed Jul 01 04:00:00 EDT 1998

OSTI ID:20018965

Hankala, J

To convert an old plant is often an economically advantageous alternative for a new boiler. The most important sources of biomass in industrial countries are residues from forestry, industry and agriculture. Sludges and wastes from industry, communities and households also contain useful energy. Still in many places there are existing power plants which can be converted to burn biofuels with low investment costs. An efficient and proven way is to convert an existing boiler to fluidized bed combustion (FBC) or use atmospheric circulating fluidized bed biofuel gasification connected to an existing boiler. Modern Fluidized Bed Combustion and Gasification gives us a possibility to burn biomass, sludges and many kinds of wastes in an efficient way with low emissions. Fluidized bed technologies are divided into bubbling fluidized bed (BFB) and circulating fluidized bed (CFB) solutions. When making a boiler conversion to fluidized bed combustion, lower furnace of an existing boiler is converted and fuel receiving, handling and transportation system is installed. In many cases most of the existing boiler heating surfaces and a majority of the existing auxiliary equipment can be utilized. The circulating fluidized bed gasifier consists of the inside refractory-lined steel vessel, where fuel is gasified in a hot fluidized gas solid particle suspension. In the gasifier, the biofuels will be converted to combustible gas at atmospheric pressure at the temperature 800--900 C. The hot gas from the gasifier will be cooled down to 650--750 C in the air preheater. The hot gas is led directly to separate burners, which are located in the existing boiler furnace. The gas is burned in the boiler and replaces a part of the coal used in the boiler. Typical fuels for the FBC-boilers are wet fuels such as bark, wood waste, peat and sludges. These fuels normally contain 40--70% water.

• Research Organization: Foster Wheeler Energia (FI)
• OSTI ID: 20018965
• Report Number(s): CONF-9806214--
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
20 FOSSIL-FUELED POWER PLANTS
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
CIRCULATING SYSTEMS
FLUIDIZED BED BOILERS
FLUIDIZED BED REFUSE GASIFICATION
INDUSTRIAL WASTES
MUNICIPAL WASTES
REFUSE-FUELED BOILERS
REFUSE-FUELED POWER PLANTS
RETROFITTING
SLUDGES
WOOD WASTES