Reduction kinetics of combusted iron powder using hydrogen

Minimum Fluidization Velocity and Reduction Behavior of Combusted Iron Powder in a Fluidized Bed

“…Interestingly, the difference in surface morphology between the particles reduced above 700 K was negligible, even though the reduction degree obtained varied significantly (𝑋 = 0.2 − 0.6). This matches with the kinetic result obtained in a previous study, which indicated that the reaction progresses via a shrinking core principle (phase boundary controlled), where the conversion of iron oxide to iron starts at the surface and grows inwards, creating an oxide core with an iron shell surrounding it [15].…”

“…A dendritic iron structure can be observed, leading to a particle surface which is highly porous. This matches with results obtained in previous studies on iron oxide reduction [8,15,[55][56][57]. Only the results at 807 K and 100 vol% H 2 are presented here, while the images of the other cases are provided in the supplementary material.…”

“…Similarly, in chemical looping combustion, the metals are used to aid carbon capture and storage in fossil fuel combustion, while the metal energy carrier cycle uses renewable energy and thus is carbon-free. Our previous study investigated the intrinsic chemical kinetics of combusted iron powder with hydrogen using thermogravimetric analysis and a packed bed reactor [15]. However, for larger quantities of powder, a fluidized bed is preferred above a packed bed reactor due to greater heat and mass transfer rates.…”

Combustion, Chemistry, and Carbon Neutrality

“…Recent literature mainly considers the role of metals as energy carriers, − in heat and power generation processes, ,− and addresses also life-cycle analyses . Several metals are being discussed with numerous studies on iron ,− and aluminum, ,− also considering, e.g, lithium and magnesium. ,, Alumina combustion can be performed in air or in water, with the latter providing also hydrogen as a product. ,,, Hydrogen production on demand at any desired location, at different scales, from the highly exothermic reactions of light metals (Al, Mg, Li) with water could be a significant technological advantage. , A schematic view of an aluminum-based power generation process is shown in Figure …”

Particle Equilibrium Composition model for iron dust combustion

“…Therefore it is expected to be only accurate under fuel-rich conditions, as in fuel-lean conditions iron can oxidize further. In several different experimental set-ups [22][23][24] it is observed that, when sufficient oxygen is present, iron powder is converted to https://doi.org/ Various properties of metal oxides [16][17][18]. Changes in formation enthalpy 𝛥ℎ 𝑓 are normalized per kilogram of Fe.…”