Reactivation of partially‐sulphated limestone particles from a cfb combustor by hydration

Couturier, Michel F.; Marquis, D. L.; Steward, F.R.; Volmerange, Y.

doi:10.1002/cjce.5450720114

Cited by 45 publications

(34 citation statements)

References 4 publications

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“…In particular, for the limestone at hand the final conversion degree after resulfation was approximately twice that obtained after the first sulfation, independently of the particle size range. When the effectiveness of sorbent reactivation achieved in the present work is compared with previously published results, 5,7 it must be borne in mind that hydration was accomplished in a large excess water. Moreover, overnight drying at ambient conditions following the 60 min hydration extended the time during which the sorbent was in contact with water.…”

Section: Resultsmentioning

confidence: 93%

Enhancement of Sulfur Uptake by Hydration of Spent Limestone for Fluidized-Bed Combustion Application

Scala

Montagnaro

Salatino

2001

Ind. Eng. Chem. Res.

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The reactivation of spent limestone generated by fluidized-bed desulfurization of simulated flue combustion gases was studied. The regeneration technique consisted of spent sorbent hydration by immersion in water under controlled conditions. The effectiveness of the reactivation process was assessed by re-injection of the hydrated material in a fluidized-bed reactor under simulated desulfurization conditions. At the same time, the influence of hydration on the propensity of limestone to undergo attrition was evaluated by following the changes of particle size distribution and by collection of elutriated fines during sorbent utilization in the fluidized-bed reactor. The total calcium sulfation degree of hydrated samples was nearly twice that of the original spent sorbent. Apparently, reactivation did not bring about any significant enhancement of limestone attrition upon re-injection into the fluidized bed. Mechanistic aspects of sorbent reactivation were investigated with the aid of computer-aided scanning electron microscope-energy-dispersive X-ray analysis mapping of polished cross sections of sulfated, hydrated, and resulfated limestone particles. This analysis highlighted a pronounced redistribution of sulfur in the particles upon hydration that apparently provides the key pathway to enhanced sulfur uptake.

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Section: Resultsmentioning

confidence: 93%

Enhancement of Sulfur Uptake by Hydration of Spent Limestone for Fluidized-Bed Combustion Application

Scala

Montagnaro

Salatino

2001

Ind. Eng. Chem. Res.

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“…However, the second of these reactions is slow and can be ignored from the point of view of sorbent reactivation (Couturier et al, 1994;Anthony et al, 1997). During hydration of the partially-sulphated material, water permeates the outer CaSO 4 layer of the sorbent particles and reacts with CaO in the core.…”

mentioning

confidence: 99%

“…Since the reaction product, Ca(OH) 2 , has a larger molar volume than the CaO (33 versus 17 mL/mol), the core swells, leading to cracking of the sulphated shell. When the reactivated sorbent particles are re-injected into the fluidized bed, the Ca(OH) 2 in these particles decomposes and the previously inaccessible CaO becomes available for further sulphation (Couturier et al, 1994;Laursen et al, 2000).…”

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confidence: 99%

Experimental Studies on Hydration of Partially Sulphated CFBC Ash

Wu¹,

Anthony²,

Jia³

2003

Can J Chem Eng

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The hydration of partially‐sulphated fluidized bed combustor (FBC) ash with water was carried out at laboratory scale. The bottom ash fractions and the as‐received fly ash were hydrated for different lengths of time, at different temperatures between 5°C and 80°C. The free lime and calcium hydroxide content in the samples were analyzed before and after the hydration process. Scanning electron microscopy (SEM) with an energy dispersive X‐ray system (EDX) was employed to investigate the physical characteristics of the samples. X‐ray diffractograms (XRD) were used to obtain information on the phase composition. The current results show that, during the hydration treatment, the unreacted CaO in the partially‐sulphated material can be almost quantitatively converted to Ca(OH)2 but that the free lime content is not constant. It is also clear that effectiveness of the hydration depends on hydration time and temperature. In addition, the behaviour of different particle size fractions is different and there is evidence that the hydration of CaO is not the only reaction occurring in this system.

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“…It could be inferred from the cosphere overlap model , that there are four interactions between maltitol and glycylglycine molecules: (1) the ion–hydrophilic interaction between the ionic groups (NH 3 + , NH 2 + , and COO – ) of glycylglycine and the hydrophilic group (OH – ) of maltitol; (2) the ion–hydrophobic interaction between the ionic group of glycylglycine and the alkyl chain of maltitol; (3) the hydrophobic–hydrophilic interaction between the alkyl chain of glycylglycine and the hydrophilic group of maltitol; and (4) the hydrophobic–hydrophobic interaction between the alkyl chain of glycylglycine and the alkyl chain of maltitol. Among these interactions, the ion–hydrophilic interaction produces positive contribution to the volume, while the ion–hydrophobic, hydrophobic–hydrophilic, and hydrophobic–hydrophobic interactions cause negative contribution to Δ tr V φ 0 .…”

Section: Resultsmentioning

confidence: 99%

Volumetric and Viscometric Properties of Maltitol in Glycylglycine Aqueous Solutions at T = 293.15–333.15 K

Shi

Zhu

et al. 2020

J. Chem. Eng. Data

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The densities and viscosities of maltitol in glycylglycine aqueous solutions were measured at T = 293. 15, 303.15, 313.15, 323.15, and 333.15 K and at atmospheric pressure. Furthermore, the apparent molar volume (V φ ), the limiting partial molar volume (V φ 0 ), the limiting partial molar volume of transfer (Δ tr V φ 0 ), the viscosity B coefficient, and the active free energies per mole of the solvent and solute (Δμ 1 0≠ and Δμ 2 0≠ ) were obtained from the experimental densities and viscosities. Moreover, the limiting partial molar volume of transfer was analyzed based on the cosphere overlap model, and the active free energies were also discussed according to the transition-state theory. The results indicate that the ion−hydrophilic interaction between the maltitol and glycylglycine molecules occupies a dominant position in the solution, and maltitol tends to act as a structural maker in the glycylglycine aqueous solution.

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Reactivation of partially‐sulphated limestone particles from a cfb combustor by hydration

Cited by 45 publications

References 4 publications

Enhancement of Sulfur Uptake by Hydration of Spent Limestone for Fluidized-Bed Combustion Application

Enhancement of Sulfur Uptake by Hydration of Spent Limestone for Fluidized-Bed Combustion Application

Experimental Studies on Hydration of Partially Sulphated CFBC Ash

Volumetric and Viscometric Properties of Maltitol in Glycylglycine Aqueous Solutions at T = 293.15–333.15 K

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