盐酸等四种液体危化品挥发过程中团簇结构的研究

发布时间：2018-03-03 11:36

  本文选题：液体危化品　切入点：挥发　出处：《天津科技大学》2013年硕士论文　论文类型：学位论文

【摘要】：液体危险化学品,简称液体危化品,是易挥发、蒸气剧毒或有强腐蚀性或有强刺激性的液体,在运输、生产、储存、使用过程中经常发生泄漏事故,泄露同时伴生大量有毒气体。目前,针对液体危化品泄漏事故,如何在第一时间内有效控制有毒气体的生成与传输,是应急救援措施亟待解决的关键技术难题。然而,目前国内外有关液体危化品有毒气体生成与传输的机理研究鲜少报道。本文通过研究盐酸等四种液体危化品在不同温度下的自然挥发过程,计算液体危化品的传质系数及传质速率,运用Gaussian03计算液体危化品挥发过程中团簇结构的变化,从能量障碍角度系统研究有毒气体生成与传输的机理。本文以常见的4种液体危化品：氨水、盐酸、甲醛、硝酸为研究对象。以温度为液体危化品挥发的主要影响因素,在20℃～45℃进行了400min自然挥发实验,通过测定溶液浓度随时间的变化规律、计算传质系数及传质速率,研究4种液体危化品的挥发过程。实验结果表明,液体危化品的挥发随着温度的增加而加强,但挥发速率在温度方面都存在明显的区域性,即在相应的区域内挥发程度相似。并且,4种液体危化品中,氨水的挥发速度最快,盐酸与甲醛的挥发次之,硝酸的挥发最难进行,35℃时氨水的传质系数为1.97×10-4 m/min;盐酸为0.934×10-5 m/min;甲醛为0.880×10-5 m/min;硝酸为0.803 ×10-6m/min。本文通过团簇结构的能量计算出团簇结构变化过程中所需的能量。得出结论：氨水挥发过程中各阶段所需要的能量分别为11.09kJ/mol、13.76kJ/mol、18.67kJ/mol,氨水挥发为逐渐变慢的过程；盐酸挥发过程中各阶段所需要的能量分别为21.81kJ/mol、51.39kJ/mol、18.42kJ/mol,盐酸的挥发过程为逐渐变慢然后变快的过程；甲醛挥发过程中各阶段所需要的能量分别为22.55kJ/mol、18.98kJ/mol,甲醛的挥发过程为逐渐变快的过程；硝酸挥发过程中各阶段所需要的能量分别为63.17kJ·mol-1、 107.9kJ·mol-1,硝酸的挥发过程为逐渐变慢的过程。
[Abstract]:Liquid hazardous chemicals, referred to as liquid hazardous chemicals, are volatile, highly toxic, or highly corrosive or irritating liquids, often leaking in the course of transportation, production, storage and use. At present, how to effectively control the generation and transmission of toxic gases in the first time is a key technical problem to be solved in emergency rescue measures. There are few reports at home and abroad on the mechanism of formation and transport of toxic gases of liquid dangerous chemicals. In this paper, the natural volatilization processes of four kinds of liquid dangerous chemicals such as hydrochloric acid at different temperatures are studied. The mass transfer coefficient and mass transfer rate of liquid dangerous chemicals were calculated, and the change of cluster structure during the volatilization of liquid dangerous chemicals was calculated by Gaussian03. The mechanism of the formation and transport of toxic gases is systematically studied from the point of view of energy barrier. In this paper, four kinds of liquid dangerous chemicals: ammonia, hydrochloric acid, formaldehyde, nitric acid are taken as the research objects, and temperature is taken as the main influencing factor of volatilization of liquid dangerous chemicals. A 400min natural volatilization experiment was carried out at 20 鈩，

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