High pressure thermogravimetric analysis of the direct sulfation of Spanish calcium-based sorbents.

Álvarez, Elena; González, J.F.

doi:10.1016/s0016-2361(98)00159-8

Cited by 22 publications

(10 citation statements)

References 14 publications

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“…The porosity and pore size increase with increasing temperature and decrease with increasing conversion of the limestone. The influences of the gaseous reactants and product (SO 2 , O 2 and CO 2 ) on the direct sulfation of limestone were observed to vary with reaction conditions. The apparent reaction orders of SO 2 observed by various authors5, 6, 7, 8 are significantly lower than unity, while the apparent reaction order of O 2 was observed to drop to zero at high O 2 concentrations 4, 9, 10. Higher CO 2 concentrations were observed to depress the direct sulfation reaction under certain reaction conditions 11, 12, 13…”

Section: Introductionmentioning

confidence: 91%

“…Higher CO 2 concentrations were observed to depress the direct sulfation reaction under certain reaction conditions 11, 12, 13 The effective diffusivity in the product layer was observed to decrease with increasing conversion and SO 2 concentration 3, 7, 8, 10 Water can both significantly promote the direct sulfation reaction and increase the apparent reaction order of SO 2 3, 5 although water is not considered to participate in the reaction as a reactant. …”

Section: Introductionmentioning

confidence: 99%

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Direct sulfation of limestone

Dam‐Johansen

Wedel

et al. 2007

AIChE Journal

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in Wiley InterScience (www.interscience.wiley.com).The direct sulfation of limestone was studied in a laboratory fixed-bed reactor. It is found that the direct sulfation of limestone involves nucleation and crystal grain growth of the solid product (anhydrite). At 823 K and at low-conversions (less than about 0.5 %), the influences of SO 2 , O 2 and CO 2 on the direct sulfation of limestone corresponds to apparent reaction orders of about 0.2, 0.2 and À0.5, respectively. Water is observed to promote the sulfation reaction and increase the apparent reaction orders of SO 2 and O 2 . The influence of O 2 at high O 2 concentrations (> about 15 %) becomes negligible. In the temperature interval from 723 K to 973 K, an apparent activation energy of about 104 kJ/mol is observed for the direct sulfation of limestone. At low temperatures and low conversions, the sulfation process is most likely under mixed control by chemical reaction and solid-state diffusion. The nucleation and crystal grain growth of the solid product, and this mixed control mechanism provide satisfactory explanations of the various phenomena related to the direct sulfation of limestone, such as porosity in the product layer, the variation of the apparent reaction orders of SO 2 , O 2 and CO 2 with reaction conditions and the influence of water. 2007 American Institute of Chemical Engineers AIChE J, 53: 948-960, 2007

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Direct sulfation of limestone

Dam‐Johansen

Wedel

et al. 2007

AIChE Journal

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“…In the past decades, a number of studies5–18 on the reaction kinetics of the direct sulfation of limestone have been conducted mainly to explore economical and effective methods for SO 2 emission abatement in PFBC. The majority of the earlier works were about limestone sulfation with relatively long durations and high‐limestone conversions because of practical reasons of the related applications.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of the direct sulfation of limestone at the initial stage of crystal growth of the solid product

Dam‐Johansen

Wedel

2011

AIChE Journal

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The direct sulfation of limestone was studied in a quartz bench scale fixed-bed reactor with the technique of data deconvolution. The obtained results show that the direct sulfation of limestone has a two-period kinetic behavior: a short initial sulfation period with high but fast decreasing reaction rate and a subsequent period with product crystal growth with low-conversion rate. The transition from the first period to the second period is sharp and indicates clearly the start point of the period with product crystal growth. The transition point was determined by the concentrations of gases such as SO 2 , O 2 , and CO 2 and the temperature. The sulfation process in the initial stage of the period with product crystal growth can be described by the combination of the sulfation reaction at the gas-solid interface, diffusion of the product ions toward the product crystal grains, diffusion of carbonate ions toward the gas-solid interface to react, and the gradual shielding of calcite surface area by the product crystal grains. A simple and semi-empirical mathematical model derived on basis of this theory gives a satisfactory description of the experimental results up to a calcite conversion of about 0.5%. V V C

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“…Limited information exists on the effects of indigenous minerals in coal on the emissions of NO x and SO 2 . In the work described here, the effects of indigenous minerals in coal from China on the emissions of NO and SO 2 during coal combustion were investigated using a thermogravimetric analyzer which has been used to investigate the behavior of adsorbents through the measurement of emissions, enabling some valuable conclusions to be drawn [3][4][5]. [6][7][8] Coal from Tongchuan in China was used.…”

Section: Introductionmentioning

confidence: 99%