本文聚焦于水–甲硫醇–二甲硫醚三元体系的气液平衡开展模拟研究。鉴于该体系存在三元共沸特性,致使在甲硫醇钠生产进程中,塔顶难以获取合格的甲硫醇产品,从而对下游二甲基亚砜产品的纯度产生负面影响。为妥善解决此问题,本研究借助Material Studio和Gaussian 09W软件,构建了水、甲硫醇以及二甲硫醚的分子模型,并对其进行结构优化,同时完成COSMO文件的计算。通过运用COSMO-RS方法,对该三元体系在不同温度条件下的相互作用力以及超额焓的变化态势予以预测。研究结果表明,在不同温度区间,体系的超额焓呈现出显著差异,且范德华力在超额焓的贡献中占据主导地位。此外,本文运用Aspen软件针对该体系的二元相图展开模拟分析,结果显示NRTL方程对该体系具备良好的模拟效果。本研究成果为该体系的分离回收提供了坚实的理论支撑,有助于提升二甲基亚砜的纯度,进而有力推动其在电子等新兴市场领域的广泛应用。This paper investigates the vapor-liquid equilibrium (VLE) of the water-methyl mercaptan (MME)-dimethyl sulfide (DMS) ternary system through simulation. The presence of an azeotrope in this system leads to the inability to obtain pure methyl mercaptan at the top of the distillation column during the production of methyl mercaptan sodium, which in turn affects the purity of downstream dimethyl sulfoxide (DMSO) products. To address this issue, molecular models of water, MME, and DMS were established using Material Studio and Gaussian 09W software. The structures were optimized, and COSMO files were generated. The COSMO-RS method was employed to predict the interactions and excess enthalpy of the ternary system at different temperatures. The results showed that the excess enthalpy of the system varies with temperature, and van der Waals forces are the primary contributors to the excess enthalpy, followed by electrostatic and hydrogen bonding forces. Additionally, Aspen software was used to simulate the binary phase diagrams of the system, revealing that the NRTL equation provides good simulation results for this system. This study provides a theoretical basis for the separation and recovery of the system, which is beneficial for improving the purity of DMSO and promoting its application in emerging markets such as electronics.
在脱碳装置中,吸收塔是实现吸收CO2的主要操作设备。某企业脱碳装置在长期使用过程中,受合成气夹带杂质气体、粉尘沉积等不断累积影响,造成吸收液品质下降,导致CO2脱除不达标,同时MDEA溶液的损失也非常大,影响整个系统的运行。本文通过采用红外光谱、气质联用定性分析、酸度分析及X荧光分析等方法对吸收液进行了测试,分析了失效胺液的组成,确定了造成脱碳装置腐蚀的原因,为提出腐蚀防控对策提供了基础。结果表明,飞灰固体颗粒沉积物、煤气化合成气粉尘的垢下腐蚀、热稳盐及MDEA的分解是造成设备腐蚀的主要因素。In decarburization units, the absorption tower is the main operating equipment to achieve CO2 absorption. In the process of long-term use, the decarburization device of an enterprise is affected by the continuous accumulation of impurity gas and dust deposition carried by syngas, resulting in the deterioration of the absorbent liquid, resulting in the failure of CO2 removal, and the loss of MDEA solution is also very large, which affects the operation of the whole system. In this paper, infrared spectroscopy, qualitative analysis by gas chromatography-mass spectrometry (GCM) qualitative analysis, acidity analysis and X-ray fluorescence analysis were used to test the absorption solution, analyze the composition of the failed amine solution, determine the cause of corrosion of the decarburization device, and provide a basis for proposing corrosion prevention and control measures. The results show that fly ash solid particle sediment, underscale corrosion of coal gasification syngas dust, decomposition of heat-stabilized salts and MDEA are the main factors causing equipment corrosion.
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