In this paper, the dynamic behavior of calcium carboxylate release during Zhundong coal pyrolysis and combustion is studied via reactive molecular dynamics (ReaxFF MD) simulation. The molecular structure model of Zhundong coal is constructed based on the combination of the classic Hatcher coal model and experimental characterizations. Pyrolysis simulations on the coal model are performed at different temperatures ranging from 2000 K to 2800 K. The pyrolysis experiments are also carried out to validate the ReaxFF simulation. The results show that most of the calcium are released into the volatiles by the thermal decomposition of CM-Ca (coal/char matrix with calcium bonded) after releasing CO₂. The distributions of the calcium bonded to gas, tar and inorganics as well as the atomic calcium in the volatiles are quantitatively classified. The thermal cracking of tar fragments are significant at high temperatures leading to the conversion of calcium from tar into the organic gas. Furthermore, the nascent char model is constructed to study the release behavior of calcium in char combustion stage. The calcium is initially released in the form of oxidized calcium and atomic calcium. With increasing temperature, the oxidized calcium trends to convert to the organically bonded calcium. By using the Arrhenius expression, the kinetic parameters for the release of calcium into various species during pyrolysis and char combustion stages are quantitatively determined.

本文通过反应分子动力学（ReaxFF MD）模拟研究了准东煤热解燃烧过程中羧酸钙释放的动力学行为。结合经典的Hatcher煤模型和实验表征，构建准东煤的分子结构模型。在2000 K至2800 K的不同温度下对煤模型进行热解模拟。还进行了热解实验以验证ReaxFF模拟。结果表明，释放出CO ₂后，大多数钙通过CM-Ca（结合了钙的煤/炭基质）的热分解而释放到挥发物中。。对与气体，焦油和无机物结合的钙的分布以及挥发物中的原子钙进行了定量分类。焦油碎片的热裂解在高温下很明显，导致钙从焦油转化为有机气体。此外，建立了新生的炭模型来研究钙在炭燃烧阶段的释放行为。钙最初以氧化钙和原子钙的形式释放。随着温度的升高，氧化钙趋向于转化为有机键合的钙。通过使用Arrhenius表达式，定量确定了在热解和焦炭燃烧阶段将钙释放到各种物质中的动力学参数。