减压间歇精馏回收废液中甲苯的应用研究

发布时间：2017-12-28 19:09

本文关键词：减压间歇精馏回收废液中甲苯的应用研究　出处：《苏州科技学院》2015年硕士论文　论文类型：学位论文

【摘要】：石油、化工、机械、涂料、纤维、油脂、橡胶、医药和电子等行业中甲苯被大量地用作有机溶剂,并最终形成大量的甲苯废液。甲苯易挥发、有刺激性和毒性,对人体健康和生态环境均能造成严重的危害,但同时也具有一定的经济价值。目前,国内外高浓度甲苯废液以焚烧法处理为主,但焚烧过程中产生的一氧化碳、氮氧化物、硫氧化物、二VA英和飞灰等有害物质引起了社会的普遍担忧。因此,研究开发新型高浓度甲苯废液处理工艺和处理装置是环境、安全、资源和经济等多方面的迫切需要。本论文首次采用了减压间歇精馏工艺,通过自主设计的减压间歇精馏装置,从实验室生产废液中成功得到了分析纯规格的甲苯,实现了实验室生产废液向再生有机溶剂的转变。本论文研究对象为实验室小规模生产共混添加剂过程中产生的废液。经真空抽滤、饱和食盐水洗涤、分液等简单预处理后,采用色谱-质谱分析方法测试了废液的组分和组成,得到了废液主要组分为甲苯、乙醇和水,三者质量分数分别为89.8%,8.2%和1.0%；在对废液组成特点分析和减压间歇精馏原理充分理解的基础上,确定了采用减压间歇精馏技术回收废液中高浓度的甲苯；自行设计安装和测试了减压间歇精馏实验的实验装置,得到了填料精馏塔的理论板数N=11,填料精馏塔正常操作塔压降为400 Pa；考察了操作压力、精馏时间、回流比、废液组成等参数对减压间歇精馏过程的影响,发现：(1)随着压力的降低,甲苯纯度逐渐增加,甲苯回收率总体呈下降的趋势；(2)间歇精馏塔塔釜温度随时间变化平缓,塔顶温度的变化和塔顶组成的变化存在时间上的相关性。本回收实验通过观察记录塔顶温度的变化间接判断塔顶组成的变化；(3)随着回流比的增大,甲苯纯度和甲苯回收率均呈现出增大的趋势；(4)本回收实验操作条件：操作压力为30.4 kPa,120 min为区分前馏分段和产品段时间点,前馏分段回流比为7,产品段回流比为5的条件下,典型废液的回收产品中甲苯质量分数为99.7%,单程甲苯回收率为70.5%,二次精馏甲苯总回收率为92.2%；(5)随着乙醇／水质量比的增加,甲苯回收率总体上呈现上升的趋势。在精馏实际废液前需要采取干燥等措施降低废液中水的含量；(6)在模拟废液中水质量分数保持在2%的前提下,甲苯／乙醇质量比低于1,减压间歇精馏实验分别无法进行,低于4时获得低回收率甲苯,高于9时获得高回收率甲苯。在精馏实际废液前需要采取饱和实验水洗涤等措施降低废液中乙醇的含量；依据相关的国家标准,减压间歇精馏实验所得产品经检测为分析纯甲苯试剂；采用了ChemCAD软件对整个减压间歇精馏过程进行了模拟,模拟结果与实验数据吻合较好,为实验规模的扩大化奠定了基础；进行了减压间歇精馏实验的经济效益分析,结果表明实验经济效益显著。
[Abstract]:Toluene is widely used as an organic solvent in petroleum, chemical industry, machinery, coatings, fiber, oil, rubber, medicine and electronics industries, and finally a large amount of toluene waste liquid is formed. Toluene is volatile, irritant and toxic, and can cause serious harm to human health and ecological environment, but it also has a certain economic value. At present, high concentration toluene waste water is mainly incineration, but carbon monoxide, nitrogen oxides, sulfur oxides, two VA, fly ash and other harmful substances caused widespread concern in the society. Therefore, the research and development of new high concentration toluene waste liquid treatment process and treatment device is the urgent need of environment, safety, resources and economy and so on. For the first time, the vacuum batch distillation process has been used for the first time, and the pure toluene has been successfully obtained from the laboratory waste liquid by the self designed decompression batch distillation unit, and the transformation from laboratory waste liquid to regenerated organic solvent has been realized. The research object of this paper is the waste liquid produced in the process of small scale production of blending additives in the laboratory. The vacuum and saturated salt water, washing liquid after simple pretreatment, using gas chromatography-mass spectrometry analysis method of waste liquid component and the composition of the test, the waste is mainly composed of toluene, ethanol and water, the three mass fraction were 89.8%, 8.2% and 1%; understanding on waste composition analysis of the characteristics and principle of vacuum batch distillation, a high concentration of toluene were determined by vacuum batch distillation technology in recycling of waste liquid; self-designed experimental device installation and vacuum batch distillation experiment test, the number of theoretical plates N=11 packed distillation column, packed distillation column normal operation of the tower drop to 400 Pa; the effects of operation pressure, distillation time, reflux ratio, liquid composition and other parameters on the vacuum batch distillation process, found that: (1) as the pressure decreases, the purity of toluene increased gradually, the recovery rate of total body is under toluene The trend of the reduction is: (2) the temperature of the batch distillation tower is slow with time, and the change of the top temperature of the tower and the change of the composition of the top of the tower has the correlation of time. The recovery experiment by observing the changes of the temperature at the top of the record to determine changes in composition of the indirect overhead; (3) when the reflux ratio increased, and the purity of toluene toluene recovery rate showed increasing trend; (4) the recovery experiment of operating pressure of 30.4 kPa and 120 min to distinguish the fraction and product segments the point in time, before the fraction reflux ratio is 7, the product section of reflux ratio is 5, the mass fraction of toluene recovery in 99.7% typical waste products, one-way toluene recovery rate was 70.5%, two times the total recovery of toluene distillation rate was 92.2%; (5) with the increase of ethanol / water mass ratio, toluene recovery the rate of overall upward trend. In the actual wastewater before distillation need to take measures to reduce the water content of dry waste; (6) in the simulated waste water content maintained at 2% under the premise of toluene / ethanol ratio less than 1, vacuum batch distillation experiments were not less than 4, low recovery rate of toluene was higher than 9, to obtain high recovery rate toluene. In the actual wastewater need to be taken before the distillation experiment of water washing and other measures to reduce the saturated alcohol content in liquor; according to relevant national standards, vacuum batch distillation experiment for product testing by the analysis of pure toluene reagent; by vacuum batch distillation process on the whole have undergone ChemCAD simulation software, the simulation results agree well with the experimental data, which the foundation for the expansion of the scale; analyzes the vacuum batch distillation experiment results show that the economic benefits, economic benefits.
【学位授予单位】：苏州科技学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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