Preparation of Macroporous Lime from Natural Lime by Swelling Method with Acetic Acid for High-Temperature Desulfurization

Abstract

To develop a highly active calcium oxide high-temperature desulfurization sorbent, a method of preparation of macroporous calcium oxides from lime was studied. This method is composed of two steps: swelling of the lime and calcination of the swelled sample. Swelling occurred when lime was exposed to the vapor of acetic acid. The swelling resulted from calcium acetate formation in the sample. The swelling rate was at a maximum in the presence of acetic acid and depressed by the presence of water vapor. The swelled sample was converted to macroporous calcium oxide by heating to 850 °C. The reactivity of the macroporous calcium oxide for the removal of SO2 or H2S in the presence of H2O vapor was higher than that of the calcined raw limestone. In particular, its SO2 removal capacity and the oxidative character of CaS to CaSO4 and CaO were greatly improved by this swelling method. These characteristics were also compared with those of a sample prepared from limestone by this swelling method.

Adsorption characteristics of Fe(III) and Fe(III)–NTA complex on granular activated carbon

“…The increase in the specific surface area of activated carbon was due to the fact that during the swelling process a number of fine cracks and micropores were generated on the solid surface by the vaporized solvent, resulting in an increase of the surface area [29]. The observed swelling ratio for activated carbon was much smaller compared than for other solids such as lime, coal, lignite, etc., which were swollen by the same solvent [30,31]. This result was probably due to the original material nature of activated carbon, i.e., when the raw material for activated carbon was activated using proper conditions, its surface area almost reached its maximum.…”

Calcined calcium magnesium acetate as a superior SO2 sorbent: I. Thermal decomposition

“…Calcium oxide obtained by calcining calcium acetate at 800ЊC has been reported to contain pores in the size range of 0.2 to Ž . 4 m Sasaoka et al, 1997Sasaoka et al, , 1998Wu et al, 2002 . When limestone is calcined at various temperatures from 750ЊC to 1,100ЊC, the main peak having the largest pore size in the differential pore-size distribution curve appears at 950ЊC with Ž .…”

“…Since the work reported in this series of the literature that deal with making reactive CaO by first re-Ž . acting lime Sasaoka et al, 1998;Wu et al, 2002 or lime-Ž . stone Sasaoka et al, 1997 with acetic acid and water followed by calcination.…”

Nanoparticles of calcium hydroxide for wood deacidification: Decreasing the emissions of organic acid vapors in church organ environments

“…Even though, the precise description of the neutralization mechanism is beyond the scope of this paper, it seems straightforward that carbonates play as a sacrificial layer to give calcium salts unable to alter organ pipes. It is well known that calcareous materials react with acetic acid vapors [30,31]. In this sense, the behavior is similar to the alkaline reserve recommended to preserve paper documents from further degradation after a deacidification treatment.…”