Torrefied biomass can be used for various applications. The most likely ones, being co-fired with coal in pulverised coal fired power plants and in cement kilns, dedicated combustion in small scale pellet burners and gasification in entrained flow gasifiers that normally operate on pulverized coal.
Co-firing in pulverised coal fired power plants
The advantages of torrefaction are particularly recognized for use in (older) and existing pulverized coal (PC) fired power plants. Since these installations have not been designed for biomass co-firing originally, significant capital expenditures can be saved for modification of the plant when torrefied product is co-fired, instead of regular wood pellets.
The relatively low moisture content, good grindability and attractive C/H/O ratios make torrefaction an interesting pretreatment technology for gasification. In the interest of a gasifier using biomass, particle size and moisture contents are critical factors for good operation. This usually results in relatively expensive biomass feedstock.
Torrefied and pelletised biomass is already uniform in particle size and has a very low moisture content, therefore the incremental fuel cost is less important for gasification as for an industrial combustor where cheaper biomass is normally used.