在“双碳”目标的推动下，煤化工过程中低温甲醇洗（Rectisol）技术产生的酸性尾气，从环保负担转变成为硫资源高附加值利用的重要媒介。针对低温甲醇洗酸性尾气的处理提供了一种新的有效途径，能够减少硫化氢对环境的污染，降低其对人体健康的危害，助力实现绿色可持续发展的目标。同时规避传统硫化氢回收制硫磺、硫酸等产品附加值低、投资大的工艺，旨在生产附加值高、市场需求增长迅速的甲硫醇产品，为企业带来可观的经济效益。本文设计出一种低温甲醇洗工艺中的酸性废气资源化利用生产甲硫醇的工艺，并结合Aspen Plus模拟软件进行了稳态模拟研究，主要研究结果如下：

（1）针对含高碳高硫的酸性废气选用N-甲基二乙醇胺（MDEA）提硫技术分离H₂S和CO₂，由于MDEA在脱硫过程中有着较好的抗CO₂干扰性，建立MDEA二级吸收再生工艺，采用灵敏度分析模块对吸收塔和再生塔进行了参数优化。选择30.00 wt %的MDEA溶液实现H₂S和CO₂有效分离，回收得到纯度为86.59 wt %的H₂S气体，同时净化气达到排放标准（H₂S < 0.03 mg/m³）。

（2）回收的H₂S气体与甲醇在装载K₂WO₄/γ-Al₂O₃催化剂的固定床反应器中合成甲硫醇，构建反应器模型并对其优化。优化结果表明，在380℃、10 bar、质量空速2 h^-1、Me和H₂S进料摩尔比为2:1条件下，甲醇转化率达81.96%，甲硫醇选择性93.05%，实现高选择性合成目标。

（3）针对甲醇-甲硫醚（Me-DMS）共沸体系，建立变压精馏和萃取精馏单元。运用灵敏度分析工具，以TAC最小化为目标函数对两种分离方案分别进行双塔联合优化。通过TAC对比表明，对于Me-DMS共沸物的分离，变压精馏过程比萃取精馏过程更具成本优势。

（4）为了解决由常规顺序表得到的分离序列在分离Me和DMS混合物时选择将其放置到最后所面临的能耗问题，提出了将Me-DMS共沸物（MIBA）作为虚拟组分来替换顺序表中的DMS，得到新的序列列表。经过Aspen Plus严格的模拟结果表明，基于相对费用函数方法，引入虚拟组分的序列列表的分离序列方案，在年度费用和CO₂排放量方面优于其他两种方案。该工艺通过提前分离部分甲醇，使后续塔器处理量降低，较常规分离工艺，CO₂排放量减少0.50%，年度总费用降低2.25%。实现了经济性与环境友好性的协同提升，为低温甲醇洗尾气资源化利用提供了创新路径，在医药中间体、天然气加臭剂等领域具有显著应用潜力。

Under the impetus of the “dual carbon” goals, the Rectisol acidic tail gas produced in the coal chemical process has transformed from an environmental burden into an important medium for the high-value utilization of sulfur resources. This study provides a new and effective approach for the treatment of the Rectisol acidic tail gas. It can reduce the hydrogen sulfide pollution to the environment, mitigate its harm to human health, and help achieve the goal of sustainable development. At the same time, it avoids the traditional processes of hydrogen sulfide recovery to produce sulfur, sulfuric acid and other products, which have the disadvantages of low added value and high investment. The aim is to produce methyl mercaptan products with high added value and a rapidly growing market demand, bringing considerable economic benefits to enterprises. This paper designs a process for the resource utilization of Rectisol acidic waste gas to produce methyl mercaptan, and conducts a steady-state simulation study with the help of Aspen Plus simulation software. The main research results are as follows:

（1）For acidic exhaust gases containing high carbon and high sulfur, the N-methyldiethanolamine (MDEA) sulfur recovery technology is selected to separate H₂S and CO₂. Due to the good resistance of MDEA to CO₂ interference during the desulfurization process, a two-stage absorption and regeneration process of MDEA is established. The parameters of the absorption columns and the regeneration columns are optimized by the sensitivity analysis module. The 30 wt% concentration of MDEA solution is chosen to achieve effective separation of H₂S and CO₂, recovering H₂S gas with a purity of 86.59 wt%. Meanwhile, the purified gas meets the emission standards after treatment.

（2）The recovered H₂S gas and methanol are used to synthesize methyl mercaptan in a fixed-bed reactor loaded with K₂WO₄/γ-Al₂O₃ catalyst. The reactor model is constructed and optimized. The optimization results indicated that under the conditions of 380℃, 10 bar, mass space velocity of 2 h^-1, H₂S/Me molar ratio of 2:1. The methanol conversion reaches 81.96% and the methyl mercaptan selectivity reaches 93.05%, achieving the goal of high-selectivity synthesis.

（3）For the methanol-methyl sulfide (Me-DMS) azeotropic system, pressure-swing distillation and extractive distillation units are established. By using a sensitivity analysis tool, the two separation schemes were respectively optimized in a two-column combination mode with the objective function of TAC. The comparison of TAC shows that for the separation of the Me-DMS azeotrope, the pressure-swing distillation process is more cost-effective than the extractive distillation process.

（4）To address the energy consumption issue of traditional methods that separate the Me-DMS mixture at the end of the sequence, a new separation sequence list  is proposed by using the Me-DMS azeotrope (MIBA) as a virtual component to replace DMS in the original sequence list. Rigorous simulation results from Aspen Plus demonstrated that, based on the relative cost function method, the separation sequence scheme with the virtual component in the sequence list outperforms the other two schemes in terms of economy and CO₂ emissions. By pre-separating part of the methanol, this process reduces the processing load of subsequent columns, achieving 0.50% reduction in CO₂ emissions and 2.25% decrease in TAC compared to traditional processes. It achieves a synergistic improvement in economy and environmental friendliness, providing an innovative path for the resource utilization of Rectisol tail gas. This option demonstrates significant application potential in fields such as pharmaceutical intermediates and natural gas odorants.