Suspension firing of hog fuel, other biomass or peat

Patent · Tue Aug 06 04:00:00 EDT 1985

OSTI ID:6499969

Rivers, J; Cox, R L; Kramer, C D

A method is described for preparing hog fuel, other biomass, or peat for efficient burning and heat recovery in a water-wall boiler. The process requires drying the fuel to less that a 30% moisture content. The fuel is then pulverized to an upper particle size such that there are substantially no particles which will not burn in air suspension within the confines of the combustion zone and the boiler can meet emission requirements. Additionally, the pulverizing step is adjusted such that a fines portion of fuel is created of such size and in such amount that the fines portion readily self-ignites upon flame initiation. The fines provide sufficient ignition energy so that the entire flow of fuel burns without the necessity of the conventional fossil fuel support or pilot. The fuel is sized to burn in air suspension by injection into the boiler through a swirl stabilized-type burner. For one burner, not particularly optimized for burning wood, a suitable particle size range was found to comprise 65-100% less that 1000 microns and 15-85% less that 150 microns. Pulverizing is carried out preferably at low air flows so that the resulting air and pulverized fuel mixture of about 1-2 kilograms air per kilogram fuel may be directly injected by the swirl stabilized air suspension type burner into the furnace along with secondary air. Combustion in the furnace requires no supplemental or pilot fuel to maintain stability. The process has good load following characteeristics having at least a 2.5:1 turndown ratio.

• Assignee: Weyerhaeuser Co.
• Patent Number(s): US 4532873
• OSTI ID: 6499969
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
090400* -- Solid Waste & Wood Fuels-- (-1989)
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320305 -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Industrial Waste Management
42 ENGINEERING
421000 -- Engineering-- Combustion Systems
BIOMASS
BOILER FUELS
BOILERS
BURNERS
CHEMICAL PREPARATION
COMBUSTION CONTROL
COMMINUTION
CONTROL
DRYING
ENERGY RECOVERY
ENERGY SOURCES
FOSSIL FUELS
FUEL FEEDING SYSTEMS
FUEL SYSTEMS
FUELS
HEAT RECOVERY
ORGANIC MATTER
PARTICLE SIZE
PEAT
PULVERIZERS
RECOVERY
RENEWABLE ENERGY SOURCES
SIZE
SOLID WASTES
SYNTHESIS
WASTES
WOOD WASTES