化学吸收法是应用最广泛、研究最为成熟的碳捕集技术。胺吸收剂的工业应用效果最好，技术瓶颈是能耗过高和设备投资成本大。本文基于混合胺体系研发新型吸收剂，测量和分析其吸收性能和反应机理，研究新型混合胺吸收剂的捕集量、再生能耗、设备尺寸和溶剂损失等性能，对其应用性和经济性综合评价。 哌嗪（PZ）是目前工业应用效果最佳的混合胺活化剂，但其水溶性差且挥发性大，易结晶和挥发，造成溶剂损失从而增加溶剂和设备成本。羟乙基哌嗪（HEPZ）与 PZ 具有相似的分子结构，其吸收 CO2 的速率很快，且其沸点很高，挥发性远小于 PZ。本文以 HEPZ 和其与 2-氨基-2-甲基-1-丙醇（AMP）的混合溶液为研究对象进行了热力学、动力学和流程模拟的研究。 基于电解质有序双液（ENRTL）模型和 Redlich-Kwong 方程，建立了 HEPZ及 HEPZ+AMP 混合胺溶液的高预测精度和高拓展性的严格热力学模型。此建模方法仅利用平衡溶解度等实验数据便获取了关键热力学参数，极大的简化了吸收剂物性系统的构建，具有用于研发新型吸收剂的普遍适用性，且可扩展于其他的吸收体系。利用获得的热力学模型对溶剂捕集性能进行初评并对吸收剂体系的反应机理进行了分析。 针对 CO2吸收过程中反应动力学和填料塔模拟优化的计算精度问题，提出一种改进的基于活度的动力学模型，突破传统动力学模型的局限性。对吸收溶液的非理想性进行了修正，联立活度系数与吸收动力学机理方程，拟合了有负载的动力学实验数据，可对更大温度和浓度范围的有负载的溶剂的吸收速率进行准确预测，应用于基于速率的流程建模，预测结果更接近中试实验数据。 在 Aspen Plus 中建立了对 660 MWe 燃煤电厂烟道气进行碳捕集的基于速率的吸收-解吸流程仿真模型，对纯 AMP、AMP+HEPZ 和 AMP+PZ 三种吸收剂进行研究，分析了工艺参数对再生能耗的影响，得到了最优工艺参数。AMP+HEPZ 的循环吸收量比 AMP+PZ 增加了 7.7%；再生能耗为 3.18GJ/t CO2比 MEA 降低了10%，与同浓度 AMP 相近；填料塔尺寸比 AMP 溶剂降低了36.4%。AMP+HEPZ中 AMP 溶剂挥发量比 AMP 单胺溶剂降低36.1%，HEPZ 挥发量比 AMP+PZ 中的PZ 的挥发量降低了 47.9%。综合评价，在降低再生能耗、设备成本和溶剂损失成本上，AMP+HEPZ 溶剂比 AMP+PZ 和 AMP 具有更高的经济效益和工业价值。
Chemical absorption is the most widely used and well-studied technology in CCUS, and the absorbent with the best industrial application effect is amine solution. The technical bottleneck is high energy consumption and enormous investment in equipment. In this work, a new type of absorbent was developed based on mixed amine system, its absorption performance and reaction mechanism were measured and analyzed, the performance of this new type of mixed amine absorbent was studied, including the CO2 cyclic capacity, regeneration energy, equipment size and solvent loss. Finally, the application and economy are evaluated comprehensively. Piperazine (PZ) is the most commonly used activator for mixed amine in industrial application, but it has low solubility and high volatility, easy to crystallize and volatilize, resulting in solvent loss which increases the cost of solvent and equipment. N-(2-Hydroxyethyl) piperazine (HEPZ) has a similar molecular structure to PZ, its CO2 absorption rate is very fast, its boiling point is very high, and its volatility is much less than PZ. In this work, the thermodynamics, kinetics and process simulation of HEPZ and its mixed solution with 2-amino-2-methyl-1-propyl alcohol (AMP) have been studied. Based on the ENRTL model and Redlich-Kwong equation, a strict thermodynamic model with high prediction accuracy and high scalability for HEPZ and HEPZ+AMP mixed amine solutions was established. This modeling method obtains key thermodynamic parameters only by using experimental data such as equilibrium solubility, greatly simplifies the construction of absorbentphysical property system, and has universal applicability for the development of new absorbent, and can be extended to other absorption systems. With the thermodynamic model, the capture performance of absorbent was preliminarily evaluated and the reaction mechanism of absorbent system was analyzed. Aiming at the calculation accuracy of reaction kinetics and packed column simulation optimization in the process of CO2 absorption, an improved kinetic model based on activity was proposed, which broke through the limitations of the traditional kinetic model. The non-ideality of the absorption solution was modified in this improved kinetic model, and the activity coefficient and the absorption kinetic mechanism equation were combined, and the kinetic experimental data with CO2 loadings were fitted by regression. With this improved kinetic model, the absorption rate of the solvent with CO2 loadings in a wider range of temperature and concentration could be accurately predicted. Applied to Rate-based process modeling, the average relative deviation between the predicted results of simulation and the pilot experimental data can be reduced. A rigorous rate-based absorption-desorption simulation model to handle the flue gas from a 660 MWe CFPP was established in Aspen Plus to study the renewable energy consumption and absorption performance of AMP+HEPZ and AMP+PZ mixed amines for CO2 capture, and the influence of process parameters on renewable energy consumption was studied. The effect of process parameters on energy consumption was studied, and the process results with optimal process parameters were obtained. The cyclic capacity of AMP+HEPZ increased by 7.7% compared with AMP+PZ. The regeneration energy is 3.18GJ/t CO2, 10% lower than MEA, which is similar to the same concentration AMP solution. Packed tower size is 36.4% lower than AMP solvent. In the mixed system, the volatilization of AMP solvent was 36.1% lower than that of AMP solution with the same concentration, and the volatilization of activator in AMP+HEPZ was 47.9% lower than that of AMP+PZ system. Comprehensive evaluation shows that AMP+HEPZ solvent has higher economic benefits than AMP+PZ and AMP solution for reducing regeneration energy, equipment cost and solvent loss cost.
