B&W - Combustion Of Biomass

Fuel characteristics

In general, biomass fuels are evaluated on the basis of their physical and chemical properties. Here are the key characteristics:

Physical properties

• Density
• Size distribution
• Humidity
• Foreign matter

Chemical properties

• Calorific value
• Proximate analyses
• Ultimate analyses
• Ash analyses
• Ash-melting behaviour

The physical properties are used to determine the type of stokers and grate system needed. The chemical properties and specific needs determine the design of the boiler. These are important parameters for avoiding fouling and corrosion. The correct design can help extend lifetime, reduce maintenance costs, and increase availability of your biomass energy plant.

Main fuel categories
There are three primary fuel categories:

Baled material

• Straw bales from wheat, barley, hay, rice, etc.
• Stalk bales from rape, thistles, etc.

Bulk material (suspension combustion)

• Chipped wood, bark, subject to B&W Vølund standard sieve analyses
• Crushed prunings, residue, peat, etc.
• Pelletised fuels
• Particle-shaped fuels such as sawdust, bagasse, husk, etc.

Bulk material (grate combustion)

• Any biomass that do not fulfil the standard sieve analyses