Abstract

Vermiculite samples were impregnated with different amounts of calcium oxide by the conventional thermal heating technique and subject to CO₂ capture experiments in thermal analysis equipment. The amount of CO₂ captured by calcium oxide increased from 13 g of CO₂ per mol of CaO to 16.8 g of CO₂ per mol of CaO when the experiments were carried out with pure calcium oxide and vermiculite impregnated with CaO (1:1), respectively. Integral isoconversional methods of Kissinger-Akahira-Sunose (KAS) and Osawa-Flynn-Wall (OFW) were used for the kinetic study of the process and good correlation coefficients were achieved. The apparent activation energy values showed that for low conversions (α < 0.3) the controlling step of the process is a mixed step where the chemical reaction and the diffusion of the reagents into the vermiculite have rates of the same order of magnitude (20 kJ < E_a < 40 kJ). For higher conversions values (α > 0.3) the apparent activation energy values suggest that the slow step is a chemical step (E_a> 40 kJ).

摘要

蛭石样品通过传统的热加热技术用不同量的氧化钙浸渍，并在热分析设备中进行CO ₂捕获实验。氧化钙捕获的 CO ₂量从每 mol CaO 13 g CO _{2增加到 16.8 g CO 2}每 mol CaO 分别用纯氧化钙和浸渍 CaO (1:1) 的蛭石进行实验。采用 Kissinger-Akahira-Sunose (KAS) 和 Osawa-Flynn-Wall (OFW) 的积分等转化方法对该过程进行动力学研究，并获得了良好的相关系数。表观活化能值表明，对于低转化率 (α < 0.3)，该过程的控制步骤是一个混合步骤，其中化学反应和试剂扩散到蛭石中具有相同数量级的速率 (20 kJ < E _a < 40 kJ)。对于更高的转化率值 (α > 0.3)，表观活化能值表明慢步是化学步 (E _a > 40 kJ)。