Fly-ash/calcium hydroxide mixtures for SO2 removal: structural properties and maximum yield

Garea, A.; Fernández, Ignacio; Viguri, Javier R.; Ortiz, Inmaculada; Fernández, J.; Renedo, M. J.; Irabien, Ángel

doi:10.1016/s1385-8947(96)03178-6

Cited by 48 publications

(44 citation statements)

References 28 publications

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“…5. It has been reported in the literature that pore sizes between 2 and 100 nm have been identified as the effective zone for the sulfation reaction between SO 2 and a sorbent prepared from Ca(OH) 2 /coal fly ash, 6 and therefore special attention has been paid to this region. The BJH procedure, which permits a better characterization of mesoporosity, was applied to obtain the pore-size distribution from nitrogen desorption data.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the preparation of sorbents for flue gas desulfurization using coal fly ash has recently been studied extensively. [5][6][7][8][9][10][11][12] It is well known that the reactivity of the hydrated sorbents depends strongly on their surface area. Fernandez et al 4 reported that the SO 2 capture activity of these sorbents generally increases with the higher specific surface area of the sorbent.…”

Section: Introductionmentioning

confidence: 99%

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Preparation and characterization of sorbents prepared from ash (waste material) for sulfur dioxide (SO2) removal

Lee

Bhatia

Mohamed

2005

J Mater Cycles Waste Manag

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Sorbents synthesized from various types of ash (coal fly ash, coal bottom ash, oil palm ash, and incinerator ash) for flue gas desulfurization were investigated. The sorbents were prepared by mixing the ashes with calcium oxide and calcium sulfate using the water hydration method. The effects of various sorbent preparation variables, such as the hydration period, the ratio of calcium oxide to ash, and the amount of calcium sulfate, on the Brunauer-EmmettTeller (BET)-specific surface area of the resulting sorbent were studied using a two-level full factorial design. The surface area of the sorbents obtained range from 15.4 to 122.1 m 2 /g. Regression models were developed to correlate the significant variables to the surface area of the sorbents. An analysis of variance (ANOVA) showed that the model was significant at a confidence level of 95%. It was found that apart from all the individual variables studied, interactions between variables also exerted a significant influence on the surface area of the sorbent. From the activity test results, it was found that sorbents prepared from coal fly ash and oil palm ash have the highest SO 2 absorption capacity. Scanning electron microscope (SEM) analysis showed that the sorbent was composed of a compound with a high structural porosity, while an X-ray diffraction spectrum showed that calcium aluminum silicate hydrate compounds are the main products of the hydration reaction.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of sorbents prepared from ash (waste material) for sulfur dioxide (SO2) removal

Lee

Bhatia

Mohamed

2005

J Mater Cycles Waste Manag

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“…The active absorbent is due to the pozzolanic reaction that takes place between fly ash and calcium oxide/calcium hydroxide which yield highly hydrated compounds such as calcium silicates and calcium aluminates which has been thought to be responsible for the improvement in solid utilization (compared to using calcium oxide/calcium hydroxide as the absorbent individually) 5 . The influence of the absorbent micro-structural properties such as the BET specific surface area, which is one of the major parameters affecting the efficiency of the absorbent in removing SO 2 , has been mentioned by a number of researchers 1,3,[5][6][7][8][9][10] .…”

Section: Introductionmentioning

confidence: 99%

“…The influence of the absorbent micro-structural properties such as the BET specific surface area, which is one of the major parameters affecting the efficiency of the absorbent in removing SO 2 , has been mentioned by a number of researchers 1,3,[5][6][7][8][9][10] . Recently, Ishizuka et.…”

Section: Introductionmentioning

confidence: 99%

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Removal of Sulfur Dioxide From Flue Gas Using Absorbent Prepared by Water and Steam Hydration

Teong

Mohamed

Bhatia

2017

AJSTD

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Active absorbent for flue gas desulfurization was prepared from coal fly ash, calcium oxide (CaO) and calcium sulfate (CaSO 4 ) by hydro-thermal process; steam and water hydration. The absorbents were examined and compared for its micro-structural properties. The experiments were conducted based on Design of Experiments (DOE) according to 2 4 factorial design. The effect of various absorbent preparation variables such as hydration period (Factor A), ratio of CaO to fly ash (Factor B), amount of calcium sulfate used (Factor C) and drying temperature (Factor D) towards the BET surface area of the absorbent were studied. The BET surface area of the absorbent was in the range of 12.9-169.3 m 2 /g. Fisher's test showed that there is a strong influence of factor A, B and D towards the absorbent surface area, while its dependence on factor C is negligible. Comparison between absorbents prepared from water and steam hydration showed that the BET surface area of absorbents prepared from water hydration gives a higher surface area, but at a lower rate. The optimum BET surface area for the prepared absorbent 169.3 m 2 /g, was obtained at the following absorbent preparation variables using water hydration; hydration period of 24 hours, ratio of CaO to fly ash of 1:2, CaSO 4 amount of 3g and drying temperature of 200˚C.

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Oil Palm Ash/Ca(OH)₂/CaSO₄ Absorbent for Flue Gas Desulfurization

2005

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The preparation, optimization and activity of active absorbent prepared from oil palm ash for the removal of SO 2 in flue gas from combustion systems were investigated. The absorbent was prepared from oil palm ash, calcium hydroxide and calcium sulfate using a water hydration process. A Central Composite Design (CCD) was used to study the influence of various absorbent preparation variables ± hydration period, amount of oil palm ash, and amount of CaSO 4 ± on the BET (Brunauer-Emmett-Teller) specific surface area of the resulting absorbent. The surface areas of the absorbents obtained were in the range of 18.7±147.2 m 2 /g. It was found that all three absorbent preparation variables studied have a significant positive influence on the BET surface area of the resulting absorbent. An empirical model was then developed to correlate the three absorbent preparation variables to the BET surface area of the resulting absorbent. The model showed significance at a confidence level of 95 % using Analysis of Variance (ANOVA). Based on the empirical model, a maximum specific surface area of 128.6 m 2 /g exists within the range of the experimental variables investigated. The hydration conditions that result in the maximum surface area are a hydration period of 10 h, amount of oil palm ash 15.0 g, and amount of CaSO 4 2.7 g. Experimental validations of these predicted optimum hydration conditions gave surface areas in the range of 125.9±129.5 m 2 /g. These results are in excellent agreement with the predicted value. In addition, desulfurization activity tests showed that the absorbent derived from oil palm ash/Ca(OH) 2 /CaSO 4 exhibited a higher desulfurization capacity compared to its starting materials.

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Fly-ash/calcium hydroxide mixtures for SO2 removal: structural properties and maximum yield

Cited by 48 publications

References 28 publications

Preparation and characterization of sorbents prepared from ash (waste material) for sulfur dioxide (SO2) removal

Preparation and characterization of sorbents prepared from ash (waste material) for sulfur dioxide (SO2) removal

Removal of Sulfur Dioxide From Flue Gas Using Absorbent Prepared by Water and Steam Hydration

Oil Palm Ash/Ca(OH)₂/CaSO₄ Absorbent for Flue Gas Desulfurization

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Fly-ash/calcium hydroxide mixtures for SO2 removal: structural properties and maximum yield

Cited by 48 publications

References 28 publications

Preparation and characterization of sorbents prepared from ash (waste material) for sulfur dioxide (SO2) removal

Preparation and characterization of sorbents prepared from ash (waste material) for sulfur dioxide (SO2) removal

Removal of Sulfur Dioxide From Flue Gas Using Absorbent Prepared by Water and Steam Hydration

Oil Palm Ash/Ca(OH)2/CaSO4 Absorbent for Flue Gas Desulfurization

Contact Info

Product

Resources

About

Oil Palm Ash/Ca(OH)₂/CaSO₄ Absorbent for Flue Gas Desulfurization