Development and Test of a Rotating Drum Reactor for the Simultaneous Hydration and Carbonation of Dry Biomass Bottom Ash

• Published in: Waste and biomass valorization Vol. 13; no. 10; pp. 4319 - 4330
• Main Authors: Schnabel, Kevin, Brück, Felix, Pohl, Sven, Weigand, Harald
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 2022; Springer Nature B.V
• Subjects: Ambient temperature; Ashes; Biomass; Bottom ash; Carbon dioxide; Carbonates; Carbonation; Emissions; Engineering; Environment; Environmental Engineering/Biotechnology; Feeding behavior; Greenhouse effect; Greenhouse gases; Humidification; Hydration; Industrial Pollution Prevention; Moisture content; Moisture effects; Original Paper; Reactors; Renewable and Green Energy; Rotation; Slumping; Temperature requirements; Waste Management/Waste Technology; Water content; Hydration; Carbon capture and storage; Alkaline waste; Accelerated carbonation
• ISSN: 1877-2641; 1877-265X
• DOI: 10.1007/s12649-022-01784-z

Carbonation of biomass ash allows for the final storage of CO 2 as solid carbonates and may therewith contribute to supply energy with net negative greenhouse gas emissions. Accelerating the reaction under ambient temperature and pressure requires presence of water as reaction space. Therefore, dry-discharged ashes need to be humidified. Here we developed and tested a rotating drum reactor integrating hydration and carbonation of biomass bottom ash (BBA). The bed motion was evaluated with moist quartz sand (QS) as a model material. In the BBA carbonation experiments, liquid-to-solid ratios (L/S) between 0.1 and 0.3 were adjusted with two-fluid nozzles. The reactant gas (10 vol% CO 2 ) was fed either simultaneously with or subsequently to humidification. The CO 2 uptake was determined gravimetrically as well as using a gas balance and was compared to results obtained under fixed-bed conditions. In the rotating drum, a favorable slumping motion of the QS was identified at a rotation rate of 7 rpm and a fill level of 20 vol%. Thus, BBA carbonation tests were carried out under these conditions yielding a CO 2 uptake between 22 and 31 g/kg within 2 h. Uptake was highest at L/S 0.1 and lowest at L/S 0.3. These results indicate that the rotating drum reactor reduces the required moisture content compared to fixed-bed carbonation. The CO 2 feeding mode (simultaneous or subsequent) had only a minor effect on the cumulative CO 2 uptake but provided valuable insight into the heat production by hydration and carbonation of BBA in the rotating drum system. Graphical Abstract