Technical Challenges in Firing Biomass in Pulverized Fuelled Boilers—Industry Experiences

Biomass fuels offer very attractive options for fossil fuelled boilers, with reduced level of Carbon-di-oxide emission. In many parts of North America provincial and jurisdictional regulation on restrictions of Carbon-dioxide (CO₂) emissions level are compelling the electric utilities to explore and gradually shift to biomass Fuels. Many utilities are exploring the options of firing biomass fuels on the existing boilers either as co-firing with coal or completely switching over to biomass fuels.

However depending on their origin, biomass fuels could be very corrosive and have high  potentials to cause fouling and corrosion at the usual operating temperatures of conventional subcritical pulverized fuel boilers (540-560⁰C). There have been numerous experiences of corrosion related issues in boilers either co-firing biomass with coal or using complete biomass fuel combustion technique. A shift to biomass fuels proves to be a challenging task with respect to design and construction and operation of such boilers to get the desired level of efficiency.

The following pages  of this review article describes in details, the characteristics of biomass fuels, their effects on various boiler materials, resultant corrosion and the ways to mitigate the same. The design standards and industry experiences are also referred as the yardstick for proper design of biomass fired boilers.