Beware the biomass dust, ABTO says

The Association of Bulk Terminal Operators (ABTO) focused on the current challenges that bulk terminal operators are facing with regards to the transition from coal to biomass. During its inaugural conference in London last week, Professor Mike Bradley warned that the accumulation of biomass dust can increase the fire and explosion risks, particularly as some biomass cargoes are self-heating.

Professor Bradley, Director of the Wolfson Centre, said that biomass is not one material and urged for carefully evaluation of  the various types of biomass products before investing in new handling and storage facilities.

     “Different biomass products have different requirements,” he said, explaining that biomass products can be made up of anything from organic residues, food waste, sewage, straw, cereal and olive stones to chipped wood, elephant grass, wet leaves and paper. The key is to understand the properties of the particular range of materials involved since no one handling system can deal with all types of biomass.”

Going on to highlight some of the unloading and handling challenges faced by operators looking to adapt their terminals for biomass, he advised operators to keep a close eye on their quality control and safety procedures. Biomass dust, he said, is a particular challenge.

“Dust has caught more people out in biomass handling,” he said. “It’s more mobile, it’s lighter and will stay suspended for longer.” He said there is a danger that if not dealt with appropriately, it could result in terminal workers inhaling the dust and contracting “farmer’s lung”, the accumulation of mould spores in the lungs.

Bradley also said that the accumulation of biomass dust can increase the fire and explosion risks, particularly as some biomass cargoes are self-heating.

“If you can write your name in the dust, you have an accident waiting to happen.”

The storage of biomass products, specifically wood pellets, was a key point raised by TBA’s Dr Mi-Rong (Kimberly) Wu. She informed more than 50 bulk industry leaders that biomass volume, rather than weight, has to be taken into account when considering silos and storage facilities.

She said that because of its bulk density, more volume of solid biomass needs to be stored compared to coal and this would require about 1.3 times more land to accommodate the higher volumes. Wu also said that solid biomass is sensitive towards degradation and should not be stored for more than three months.

    “Silos have been known to explode because of incorrect handling. For solid biomass products, temperature and CO emissions must be constantly monitored,” she told delegates.

Summing up her presentation, she said: “Solid biomass properties are in a wide variation range. For solid biomass handling, the volumetric performance should be the main benchmark rather than tonnage performance.”

For those terminal operators considering a transition from coal to biomass, she said adjustments in terms of handling processes and storage requirement are necessary, along with in-depth investigations into logistics and material characteristics.