Abstract:

The micro-mechanism of the scaling of pipelines in the cooling system under deep mine was studied. Firstly, the composition and content of the ions in the mining water were determined by the full analysis of water quality, and then the chemical model and mathematical model were built, finally, the adsorption of scaling ions on iron surface was calculated by using the VASP software based on density functional theory (DFT). The result shows that, ① the scaling of the cooling system includes the combination of Ca²⁺ and CO₃²⁺ and the transform of MgCO₃, CaSO₄ to CaCO₃; ② the scaling ions (Ca²⁺,HCO^-,Mg²⁺ and SO₄^2-) are the main factors leading to the CaCO₃ scaling of the cooling system pipelines under deep coal mine and Mg²⁺ and SO₄^2- could restrain the scaling. The research is of great importance to the understanding of the scaling of the cooling under deep coal mine, pretreatment, and descaling, in order to guarantee the cooling effect and production safety for the geothermal engineering.

Key words: scaling, surface, adsorption, numerical analysis, density functional theory

摘要：

以深部矿井降温系统管道内壁出现的结垢问题为研究对象，首先采集管道水样进行水质全分析测试，确定管道内成垢性离子并建立化学及数学模型，其次采用第一性原理计算方法研究得到了深部矿井降温系统管道结垢微观机理。结果表明，深井降温系统管道内壁结垢过程包括Ca²⁺和CO₃²⁺的结合结晶及MgCo₃、CaSO₄转化为CaCO₃的转化；理论分析及第一性原理计算结果表明，深井降温系统管道内壁结垢的主要影响因素为成垢性离子（Ca²⁺、HCO^-、Mg²⁺和SO₄^2-），且和的存在会抑制碳酸钙结垢的产生。该研究对于深部高温热害矿井的降温系统的结垢产生机制以及采取合理的防、除垢措施，保障良好的矿井降温效果和安全生产具有理论指导意义。

关键词: 结垢, 表面, 吸附, 数值分析, 密度泛函理论