Kinetics of chemical absorption of carbon dioxide into aqueous calcium acetate solution

Abstract

Increasing energy demand in the world leads to more electricity generation mainly at fossil fuel power plants. Greenhouse gases are thus produced and mostly emitted to the atmosphere directly, resulting in global warming and climate change. Carbon dioxide is believed to be a main pollutant among greenhouse gases responsible from global warming. Conventional systems using mostly amine solutions to capture carbon dioxide at the source have some disadvantages, and alternatives are constantly being searched. In this work, a benign system of aqueous calcium acetate solution was investigated for this purpose. Calcium acetate is easy to produce, relatively cheap, environmentally friendly, nonhazardous, and noncorrosive. These properties make it a great alternative for use in capturing carbon dioxide. This absorption process is accompanied by chemical reaction. Therefore, the reaction kinetics needs to be investigated before its use in absorbers. A stirred cell reactor was used in the experiments using aqueous calcium acetate solution of different concentrations (2‐20% w/w) and different carbon dioxide concentrations in gas mixtures (4.5‐100% v/v dry carbon dioxide) at temperatures ranging from 286 to 352 K. The Gibbs free energy change for the overall reaction between carbon dioxide and aqueous calcium acetate solution was found to be –2.75 kJ/mol that shows the reaction is exergonic and occurs spontaneously. It was also found out that the reaction is pseudo–first order with respect to carbon dioxide which was also proven by calculating the Hatta number. Activation energy and Arrhenius (frequency) constant were also determined experimentally.

Simple and Rapid Synthesis of Calcium Acetate from Scallop Shells to Reduce Environmental Issues

“…CA has been extensively reported as a promising chemical for environmental and industrial applications [28]. CA can be used in the environmental field, as the best alternative material for replacing the corrosive and environmentally unacceptable deicers (sodium chloride and calcium chloride) [23], as a powerful SO 2 , NO X , and toxic particulate emission control agent in coal combustion processes to reduce acid rain [29], as an effective catalyst for the facilitation of coal combustion [30], and as an adsorbent of carbon dioxide [31]. In the food industries, it has been used as a stabilizer and preservative in many food substances under the number E263, as a stabilizer in most hard candies, as an antiroping agent in most commercially sold breads, as a stabilizer in baby food and syrups, and as coagulate soy milk in the commercial manufacture of tofu [32].…”