We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Accumulation of Ash-Forming Elements in Blast-Furnace Slag Bed Material during Fluidized Bed Combustion of Woody Biomass, Sludge, and Plastic Waste
AI summary Read the abstract
Researchers tested burning wood, sludge and plastic waste together with blast-furnace slag (a material used instead of sand) in a pilot-scale furnace. Compared to sand, the slag collected less coating from alkali metals, which can cause clumping problems, while heavy metals built up when sludge was used and titanium and antimony increased with plastic-containing fuels.
Abstract There is growing interest in utilizing waste fractions in energy boilers. These fuels typically increase bed agglomeration in fluidized bed combustion due to their high concentrations of melt-forming compounds. Alternative bed materials, such as blast-furnace slag (BFS), have been proposed as a solution to prevent bed agglomeration. Understanding the interactions of BFS with ash-forming elements is important for understanding its applicability with various waste fuels. Herein, the fate of ash-forming elements was investigated in fluidized bed combustion when using waste-derived fuels together with BFS bed material, and natural sand as a reference. The experiments were conducted using a pilot-scale bubbling fluidized bed reactor. Wastewater sludge, containerboard mill sludge, and containerboard mill sludge with plastics were cofired with wood. Bed particle samples were collected and analyzed for their chemical composition and morphology. Coating of alkali metals onto BFS was reduced by 69–94% in comparison to natural sand, while Ca, Fe, P, and Mn were enriched onto layers of both bed materials. The BFS inner layers were predicted to contain only high-melting-point compounds based on the layer chemical composition and equilibrium calculations, which is favorable to reducing the severity of coating-induced agglomeration. The inner layer was predicted to contain a mixture of silicates containing Ca, Fe, and K that was interpreted to form through diffusion and substitution reactions in the silica structure. The used waste fuel clearly influenced the accumulation of specific elements in bed particles: several heavy metals accumulated with wastewater sludge, while titanium and antimony were found in increased concentrations when using plastic-containing fuels. Overall, the results of this study provide valuable insights into the accumulation of fuel-derived impurities into BFS bed particles, which is important both for assessing strategies to reduce bed agglomeration in waste-fired boilers, as well as potential extraction of valuable elements from bed materials.
More Papers Like This
Can incineration completely eliminate plastic wastes? An investigation of microplastics and heavy metals in the bottom ash and fly ash from an incineration plant
AI summary Read the abstract
Researchers examined fly ash, bottom ash, and surface soil from a municipal solid waste incinerator for microplastics and heavy metals, finding that incineration did not completely eliminate plastics — with fibers persisting in fly ash — and that fly ash heavy metal concentrations exceeded safety thresholds in several categories.
Determination of sand mass flow rate in a test reactor
AI summary Read the abstract
This thesis measured bed material mass flow rate in a fluidized bed test reactor for plastic pyrolysis, providing data needed to optimize conditions for converting plastic waste into fuel as a circular economy strategy to address the growing global plastic recycling gap.
Leaching Agent and Iron Distribution Co-Treatment Regulates the Distribution and Migration of Pollutants in Heap-Leached MSWI-BA
AI summary Read the abstract
Researchers studied how different chemical leaching agents and iron placement affect the movement of microplastics and heavy metals through incineration ash when it leaches — finding that sodium carbonate dramatically increased microplastic mobility by 49% and heavy metal concentrations by up to 40-fold compared to controls, with iron placement further amplifying these effects. The findings have practical implications for how ash from waste-burning facilities is stockpiled and managed, since improper handling could allow microplastics and toxic metals to migrate into soil and groundwater. Incineration ash landfills represent an underappreciated reservoir of microplastic contamination.
Removal of Microplastics using Ground Granulated Blast Furnace Slag
AI summary Read the abstract
Lab tests mixed polyethylene microplastic particles with ground granulated blast furnace slag, a leftover material from steelmaking, in water samples. Adding more slag reduced microplastic levels in the water, while larger microplastic particles were harder to remove. Researchers concluded the slag shows potential for microplastic removal but said more research is needed.
The behaviour of plastic particles during pyrolysis in bubbling fluidized bed reactors: Incipient agglomeration and axial segregation
AI summary Read the abstract
This study used X-ray imaging techniques to investigate the behavior of single polypropylene particles during pyrolysis in a bubbling fluidized bed reactor at 500–650°C. Results showed that the sinking-floating behavior of plastic particles is not simply explained by density changes from sand-plastic agglomerate formation, with axial segregation and stochastic models better capturing the complex dynamics observed.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.