Ultrasound assisted Peroxone, a novel air pollution control technique

超声波辅助 Peroxone，一种新型空气污染控制技术

• 批准号: RGPIN-2014-04427
• 负责人: DeVisscher, Alex
• 金额: $ 2.11万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611029
• 关键词: Ultrasound; assisted; Peroxone; novel; air

Air pollution is an ongoing concern for many industrial processes. Volatile organic compounds (VOCs) form an important class of air pollutants because of their involvement in smog formation (trophospheric ozone), and the toxic and/or carcinogenic nature of some VOCs. While effective strategies exist to treat large and concentrated VOC emissions, small and dilute emissions are often untreated although their aggregate emission is substantial. An example is benzene emissions from glycol dehydration units in the natural gas sector, with an annual emission of about 2000 tons in Canada, spread over several thousands of small sources. A waste gas treatment technique that received interest in the past is the peroxone technique, which is the combination of hydrogen peroxide and ozone for the chemical oxidation of pollutants. What limits the effectiveness of this technique is the low solubility of ozone, because the reactions leading to pollutant degradation occur in the water phase. In addition, ozone is highly reactive in peroxone systems, with reaction times of less than a millisecond. As a result, only a very thin layer near the liquid surface is chemically active. However, ozone and hydrogen peroxide are known to be effective pollutant oxidizers in clouds, thanks to the finely dispersed nature of cloud droplets. It follows that the peroxone process can be made substantially more effective by using it in the form of a mist. Mists with a mean droplet size of 20 micrometer or less can be created with ultrasonic waves, similar to the droplet size in clouds. Hence, it is expected that a peroxone system will be substantially more effective if the hydrogen peroxide solution is delivered as an ultrasonic spray. The objective of the proposed project is to test this hypothesis experimentally and through modeling, and to use it as a basis for developing a new class of efficient advanced oxidation techniques for waste gas treatment. This project fits into an overall research programme with the long-term objective of developing a suite of waste gas treatment techniques capable of treating air pollutants emitted by the oil and gas sector and the manufacturing sector. Other techniques that are currently being studied by my group are biofiltration and ultraviolet degradation. All the required equipment for this project is available in my lab, with the exception of an ultrasonic spray generator. Experiments will be carried out with benzene as the pollutant, in a wide range of experimental conditions. Benzene degradation will be measured by gas chromatography analysis of influent and effluent samples. On the modeling side, a comprehensive chemical mechanism will be developed to help interpret the experimental data, and to aid the optimization of the process with the objective of scaling up. My research group has extensive experience with modeling these reactions in the gas phase. The liquid phase system is different due to the presence of ions, and to the different reaction rate constants and concentrations. We will carry out a comprehensive literature search on the kinetics of all the relevant reactions, and include the reactions in the model. By means of mass transfer modeling we will verify the assumption that the mass transfer equilibration time is sufficiently short to justify the assumption of complete mixing. Additional calculations on droplet evaporation and coalescence will be carried out to determine the eventual fate of the mist droplets. This consideration would be of importance in the eventual scale-up of the process to industrial scale. If the research is successful, participation of industrial partners will be sought to develop and build a pilot scale version of the process, and test it at an actual industrial site.

空气污染是许多工业流程持续关注的问题。挥发性有机化合物 (VOC) 是一类重要的空气污染物，因为它们参与烟雾（营养层臭氧）的形成，并且某些 VOC 具有毒性和/或致癌性。虽然存在有效的策略来处理大量且集中的挥发性有机化合物排放，但少量且稀释的排放通常未得到处理，尽管它们的总排放量很大。一个例子是天然气行业乙二醇脱水装置的苯排放，加拿大年排放量约为2000吨，分布在数千个小型源头。 过去引起人们兴趣的废气处理技术是过氧酮技术，它是过氧化氢和臭氧的结合，用于污染物的化学氧化。限制该技术有效性的是臭氧的低溶解度，因为导致污染物降解的反应发生在水相中。此外，臭氧在过氧酮系统中具有高度反应性，反应时间小于一毫秒。因此，只有靠近液体表面的非常薄的一层具有化学活性。然而，由于云滴的精细分散特性，臭氧和过氧化氢被认为是云中有效的污染物氧化剂。由此可见，通过以雾的形式使用过氧酮工艺可以大大提高其效率。 超声波可以产生平均液滴尺寸为 20 微米或更小的雾，类似于云中的液滴尺寸。因此，预计如果过氧化氢溶液作为超声波喷雾输送，则过氧酮系统将显着更有效。该项目的目标是通过实验和建模来检验这一假设，并将其作为开发新型高效废气处理高级氧化技术的基础。 该项目属于总体研究计划，其长期目标是开发一套能够处理石油和天然气行业和制造业排放的空气污染物的废气处理技术。我的小组目前正在研究的其他技术是生物过滤和紫外线降解。 我的实验室提供了该项目所需的所有设备，但超声波喷雾发生器除外。实验将以苯为污染物，在各种实验条件下进行。苯的降解情况将通过进水和出水样品的气相色谱分析来测量。 在建模方面，将开发一个全面的化学机制来帮助解释实验数据，并帮助优化工艺以达到扩大规模的目的。我的研究小组在模拟这些气相反应方面拥有丰富的经验。由于离子的存在以及不同的反应速率常数和浓度，液相系统是不同的。我们将对所有相关反应的动力学进行全面的文献检索，并将这些反应纳入模型中。 通过传质建模，我们将验证传质平衡时间足够短以证明完全混合假设的假设。将对液滴蒸发和聚结进行额外的计算，以确定雾滴的最终命运。这种考虑对于最终将该工艺扩大到工业规模非常重要。 如果研究成功，将寻求工业合作伙伴的参与来开发和构建该工艺的中试规模版本，并在实际工业现场进行测试。