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: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=637775
• 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过程的持续关注。挥发性有机化合物（VOC）构成了一类重要的空气污染物，因为它们参与了烟雾形成（Trophosperic ozone）以及某些VOC的有毒和/或致癌性。尽管存在有效的策略来治疗大型和集中的VOC排放，但小小的和稀释的排放通常是未经治疗的，尽管它们的骨料排放量很大。一个例子是天然气部门中乙二醇脱水单元中的苯排放，加拿大大约2000吨的每年排放量，分布在数千个小型来源上。过去感兴趣的废气处理技术是过氧酮技术，这是对污染剂的化学氧化氧化氧化物和臭氧的组合。限制该技术的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，在过氧系统中，臭氧具有高反应性，反应时间小于毫秒。结果，在液体表面附近只有非常薄的层是化学活性的。然而，由于云滴的分散性质，臭氧和过氧化氢是云中有效的污染物氧化剂。因此，通过以薄雾的形式使用过氧化过程可以使其更有效。平均液滴大小为20微米或更少的液体可以用超声波产生超声波，类似于云中的液滴大小。因此，如果过氧化氢溶液作为超声喷雾递送，则预计过氧系统将更加有效。拟议项目的目的是通过实验和建模来检验这一假设，并将其用作开发新的有效的高级先进氧化技术来进行废气处理。该项目符合整体研究计划，其长期目标是开发一系列能够通过油和天然气部门和制造业部门散布的废气处理技术来开发一套废气处理技术。我组目前正在研究的其他技术是生物过滤和紫外线降解。除超声喷雾发电机外，我的实验室都可以在我的实验室中获得所有所需的设备。实验将以苯作为污染物进行，在广泛的实验条件下。苯降解将通过进水和废水样品的气相色谱分析来测量。在建模方面，将开发一种综合化学机制来帮助解释实验数据，并帮助其优化，以扩大规模。我的研究小组在在气期间对这些反应进行建模方面具有丰富的经验。由于离子的存在以及不同的反应速率常数和浓度，因此液相系统有所不同。我们将对所有相关反应的动力学进行全面的文献搜索，并在模型中包括反应。通过传质建模的方式，我们将验证以下假设：质量转移平衡时间足够短，足以证明完全混合的假设。将进行有关液滴蒸发和聚结的其他计算，以确定雾液滴的最终命运。这种考虑在最终对工业规模的规模扩大中至关重要。如果研究成功，则将寻求工业伙伴的参与来开发和建立该过程的试验量表版本，并在实际的工业网站上对其进行测试。