Carbonation, Regeneration, and Cycle Stability of the Mechanically Activated Ca(OH)₂ Sorbents for CO₂ Capture: An In Situ X-ray Diffraction Study

Abstract

The impact of mechanical activation on calcium hydroxide-based sorbent was investigated. Carbonation/decarbonation kinetics and sorbent cycle stability were characterized by in situ X-ray diffraction. By increasing the speed of ball milling, we could reduce the particle size and crystallite size while increasing the pore volume in the sorbent as evidenced by XRD, dynamic light scattering, and nitrogen physisorption. At 700 °C, mechanically activated (500 rpm planetary ball milled) sorbent showed a 24% increase in capture capacity over 10 isothermal carbonation–regeneration cycles when compared to the sorbent without mechanical activation. The possible reason behind this improvement is discussed, which links the microstructure evolution and sorbent regeneration rate.

Synthesis of Novel Biolubricants from Waste Cooking Oil and Cyclic Oxygenates through an Integrated Catalytic Process

“…The average pore size of catalysts was also measured during the BET analysis. The catalyst samples were characterized by Cu Kα radiation (λ = 1.5418 Å) using a benchtop powder X-ray diffraction (XRD) system (AXRD, Proto manufacturing, MI) from 20 to 100° (2θ) with 2 s of dwell time and 0.014° of Δ2θ at 30 mA and 40 kV according to Hassani et al…”

Investigations on Kinetics and Mechanisms of CaCO3 Calcination in Calcium Looping

“…The degree of calcination per cycle is much deeper than that in the actual reactor of Ca-looping. Based on the above experimental data, the kinetic parameters and mechanism are investigated: the apparent activation energy ( E ) is calculated using the model-free isoconversional method, and the reaction model is then determined using the Master Plot approach , in combination with X-ray diffraction spectra of the solids. , The model-free isoconversional method is used to obtain the kinetic parameter data without the prior assumption of a kinetic model. − Analysis of a large number of carrier samples can minimize random variations in the surface properties of the actual carriers . The evolution of the microscopic structure of the sample is then investigated, the preferred orientation of the microstructure is obtained, and a new correlation between the macroscope kinetic model and the microscope crystal structure is established.…”