【作者】 罗铭芳；

【导师】 李鑫钢；

【作者基本信息】 天津大学 ， 化学工程， 2004， 硕士

【摘要】 环氧乙烷氨解法是目前生产乙醇胺的主要方法，产品比例、产品质量及能耗是乙醇胺生产中的三个关键因素。国内乙醇胺生产中普遍存在产品色度高、产品比例不合理的问题，造成产品缺乏竞争力。色度问题主要是由于分离系统存在的问题引起的，如精馏塔内压降大、釜温高、相关设备选型不合理等。本文采用流程模拟软件PRO/Ⅱ对乙醇胺装置进行全流程模拟，针对流程特点提出改进措施，并对精馏系统的设备因素进行考察，以期解决上述问题。乙醇胺及其原料氨和水均为极性组分，模拟中在不同场合分别选用状态方程SRKM或液体活度系数模型NRTL，可以得到比较准确的模拟结果。在原工艺的基础上，通过将分离出的一乙醇胺（MEA）部分循环回反应部分，可以显著提高二乙醇胺（DEA）和三乙醇胺（TEA）产品的收率，提高了原装置的灵活性，但是需增加设备投资及提高装置能耗。不同乙醇胺产品之间的沸点差较大，从精馏的角度来说易于分离，利用这一特点，本文开发出了带循环物流、侧线出料的精馏系统新流程。模拟计算表明，采用该流程可以显著降低MEA塔和DEA塔的塔釜温度，防止物料高温热解，为降低产品色度创造了必要条件；同时产品纯度保持在99%（重量百分数）以上，能够满足质量要求。乙醇胺为热敏物系，对分离设备的要求较高。精馏塔适合采用填料塔，塔顶冷凝器宜采用卧置部分冷凝器，TEA塔也可采用塔顶泵循方式取热，这些措施利于减小压降；再沸器选用降膜蒸发器，可防止液层静压并减少物料在高温区的停留时间。流体力学核算结果表明，选用合适的填料及分布器，能够将全塔压降控制在一定的范围以内，从而保证了塔釜温度不会过高，为产品质量提供了保障。利用本文的研究成果，可以为乙醇胺生产装置提供完整的工艺包。更多还原

【Abstract】 Ethanolamines are commonly made by the method of reacting aqueous ammonia and ethylene oxide. Product profile, product quality and energy consumption are three key factors in ethanolamine process. Domestic product is weak in competition because of poor color quality and improper product profile, which are very common in domestic ethanolamine units. The poor color quality is caused primarily by the disadvantage in separating system, such as high pressure drop in distillation tower, high temperature at the bottom of the tower, and unsuitable choice of relative devices. By means of flowsheeting software PRO/Ⅱ, the process for ethanolamine unit was simulated in this paper, then some modification was made according to the feature of the process. The factors relating to devices in distillation system were also discussed to help solve the questions above-mentioned.As ethanolamines and their crude material ammonia and water are all polar components, the considerably accurate results can be obtained by using equation of state SRKM or liquid activity model NRTL in different units. On the basis of initial process, by recycling some of the monoethanolamine separated to the reaction system, the yield of diethanolamine and triethanolamine was increased greatly, which enhanced the flexibility of the unit, but more cost was needed for some new devices and the energy consumption was increased.Ethanolamine series are easy to be separated by distillation technology because of their high boiling point difference. According to this feature, an optimized distillation process with recycling streams and sidedraws was presented in this study. The simulating results showed that the temperature at the bottom of monoethanolamine tower and diethanolamine tower was reduced greatly, which helps to prevent the degradation of the solutions, so the color index can be lowered, at the same time the product purity was kept above 99% (by weight). As heat-sensitive material, ethanolamines have more critical requirement on the separating devices. Packed tower was suitable for the distillation, horizontal partial condenser was used as top condenser, and pumparound may also be used for triethanolamine tower, which helps to reduce the pressure drop; falling-film evaporator was used as reboiler, which eliminates the liquid static pressure and helps to reduce the residence time in high temperature region. The results of hydraulic rating showed that the pressure drop in the towers can be limited to a certain degree by choosing packing and distributor correctly, so the bottom temperature may not be too high, and the product quality can be ensured.Complete process pack for ethanolamine unit was obtained by this study.更多还原