超声协助脱硫剂高效制备技术研究

发布时间：2018-03-21 00:37

本文选题：水化　切入点：超声波　出处：《大连海事大学》2017年硕士论文　论文类型：学位论文

【摘要】：大气二氧化硫污染是亟待解决的环境问题,湿法脱硫是当前应用最为广泛的脱硫方法,其中镁法脱硫是具有发展前景的技术手段。镁法脱硫以氢氧化镁为脱硫剂,其制备方法以氧化镁水化法为主。传统氧化镁水化制备氢氧化镁技术拥有反应时间长、水化效率低、最终水化率不高、设备占地大等缺陷。目前国内外围绕如何改进水化制备氢氧化镁技术展开研究,其中针对水化过程施加高温高压反应条件能有效提升水化效率,但反应过程不够温和,难以细微调控相关参数。超声波空化效应能在液相中产生局部高温高压反应条件,因此超声波协助水化技术具有重要研究价值。本文以机械搅拌水化法为基础,增加超声处理设备,改进传统水化制备氢氧化镁法。首先,比较了氧化镁在机械搅拌水化和超声水化反应条件下的效果,设计实验研究了两种反应条件下水化时间、水化温度同氧化镁水化率、水化速率的关系。其次,以反应动力学为基础分析了两种反应条件下的水化率变化,并利用相关水化动力学模型对实验数据进行拟合分析。最后,对水化后的样品进行表征测试,利用SEM、XRD、TGA、FTIR等技术分析了两种反应条件下水化产物的形貌特征、成分变化、晶型结构和水化率差异原因,并据此推导超声波提升水化反应机制,即:超声波空化效应所产的微射流和局部高温高压环境使氧化镁表水化产生的氢氧化镁沉淀剥落,裸露的氧化镁继续参与反应,从而提升了水化率和水化效率。最后得出结论：超声波对水化反应制备氢氧化镁脱硫剂具有促进作用,随超声时间增长,反应温度的提升,其水化率和水化效率同机械搅拌相比明显提升。氧化镁初始浓度为1%,反应温度为338K,一个标准大气压下,反应时间2h,机械搅拌水化率46%,超声水化率71%。
[Abstract]:Atmospheric sulfur dioxide pollution is an urgent environmental problem, and wet desulfurization is the most widely used desulphurization method, among which magnesium desulfurization is a promising technology. Magnesium hydroxide is used as desulfurization agent in magnesium desulphurization. The traditional method of magnesium oxide hydration to prepare magnesium hydroxide has long reaction time, low hydration efficiency and low hydration rate. At present, the domestic and international research on how to improve the hydration technology for the preparation of magnesium hydroxide has been carried out, in which the application of high temperature and high pressure reaction conditions to the hydration process can effectively improve the hydration efficiency, but the reaction process is not mild enough. The ultrasonic cavitation effect can produce local high temperature and high pressure reaction conditions in liquid phase, so ultrasonic assisted hydration technology has important research value. Adding ultrasonic treatment equipment to improve the traditional method of hydration to prepare magnesium hydroxide. Firstly, the effect of magnesium oxide in mechanical agitation hydration and ultrasonic hydration reaction was compared, and the hydration time of two reaction conditions was designed and studied. The relationship between the hydration temperature and the hydration rate and the hydration rate of magnesium oxide. Secondly, based on the reaction kinetics, the variation of the hydration rate under the two reaction conditions was analyzed, and the experimental data were fitted and analyzed by using the relevant hydration kinetics model. The hydrated samples were characterized and tested, and the morphology, composition, crystal structure and hydration rate of the hydrated products were analyzed by means of SEMXRDX TGAIR and other techniques, and the mechanism of ultrasonic enhancement of hydration reaction was deduced based on the analysis of the morphology, composition change, crystal structure and hydration rate of the hydrated products. That is, the micro jet produced by ultrasonic cavitation and local high temperature and high pressure environment make magnesium hydroxide precipitate and exfoliate from the hydration of magnesium oxide, and the exposed magnesium oxide continues to participate in the reaction. Finally, it is concluded that ultrasonic can promote the preparation of magnesium hydroxide desulfurizer by hydration reaction, and the reaction temperature increases with the increase of ultrasonic time. The initial concentration of magnesium oxide is 1, the reaction temperature is 338K, the reaction time is 2 h, the hydration rate of mechanical stirring is 46 and the ultrasonic hydration rate is 71.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X701.3

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