A simple method for estimating the regeneration energy of CO 2 absorption was devised. The regeneration energy of a 30 wt % sodium glycinate (SG) solution was calculated by the summation of the enthalpy of reaction, the sensible heat and the heat of vaporization. Each form of heat energy was determined experimentally. Solubilities of carbon dioxide in the SG solution was determined by gas chromatography (GC) analysis for the gas phase with the help of a virial equation for the liquid phase in the temperature range of 40-120 °C. Heat capacity of the solution was measured by a differential scanning calorimeter (DSC) and was used to calculate sensible heat. The heat of vaporization was evaluated by applying the Clausius-Clapeyron equation to 20 data points of vapor pressure. All of the experiments were carried out with either a 30 wt % aqueous solution of SG or the same concentration of monoethanolamine (MEA). Regeneration energy of the SG solution was found to be higher than that of the MEA solution by about 1000 kJ/kg of CO 2 . From the CO 2 solubility data it was observed that SG had a higher capacity to absorb carbon dioxide than MEA even at the regeneration temperature (120 °C). In addition, the 30 wt % basis SG demonstrated a reduction in cyclic capacity at this regeneration temperature. So, our main effort is to establish a reasonable method for estimating CO 2 absorbent regeneration energy along with the regeneration energy of 30 wt % aqueous solutions of SG.

No abstract

No abstract

Municipal solid waste incinerator (MSWI) fly ash was vitrified at ∼1450°C, for the first time, using Brown's gas. Vitrification of pelletized fly ash (fly ash + water glass) results in a decrease of the leaching of toxic heavy metals to much below the Korean regulatory limit values, although melted fly ash was a poorly vitrified product that had a dark gray appearance. The addition of glass cullet to the fly ash increased the silica content and decreased the basicity. It was determined that a decrease in basicity from 2.94 to 0.28 leads to good vitrified products that have an amorphous glassy structure that is dark brown in color. Leaching all of the potentially hazardous heavy metals present in fly ash also decreased as the basicity decreased. It was determined that all the heavy metals (zinc, lead, chromium, arsenic, copper, manganese, and cadmium) were efficient in regard to substituting for parent Al and Ca ions in the silicate structure. It was further confirmed by scanning electron microscopy and X-ray diffractometry studies that the initial crystalline structure of fly ash was transformed to an amorphous glassy structure upon vitrification. The vitrified products of fly ash and its mixtures with glass cullet were determined to be nonhazardous in nature and glassy in appearance; therefore, they could be considered as construction and road-building materials in the future.