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题名: 紫外反应器的优化设计方法、剂量验证和运行监测
作者: 李梦凯
学位类别: 博士
答辩日期: 2013
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 强志民
关键词: 紫外消毒 ; UV reactor ; 荧光微探头 ; micro-fluorescent silica detector ; 剂量验证 ; 优化设计 ; 长期监测
其他题名: Design optimization method, fluence validation and operation monitoring of UV reactors
中文摘要:       近年来,紫外线技术已被广泛应用于市政水厂、污水厂和二次供水等的消毒中。高效、高可靠性的紫外消毒被人们所广泛重视,包括三个关键部分:1)紫外反应器的优化设计;2)辐射剂量的精确验证;3)运行状况的在线监测。本文基于以上内容开展研究,为紫外线技术在水处理中的推广应用提供理论和技术支持。 (1)开发了一种新颖的荧光微探头,可在紫外线照射下快速激发荧光,然后通过测量荧光强度来表征紫外反应器腔体内任一点的紫外强度。该探头具有体积小(0.07 mm3)、响应快(10-6 s)、化学和热稳定性高、能在空气或水中实现在线监测等突出优点。基于荧光微探头搭建了紫外强度分布原位测试平台,可对紫外反应器内部的辐照强度分布进行原位实测,极限测试点可达仅距套管3 mm。 (2)通过原位测试平台研究了紫外反应器内壁反射对强度分布的影响。水体的紫外透过率(UVT)范围为65-99%,受试内壁材料包括石英玻璃/铝箔、石英玻璃/不锈钢和石英玻璃/黑布,其反射率分别为80.5%、26.1%和11.1%。实验结果表明,高反射率的内壁明显提升了紫外反应器内部的平均辐照强度;由于目前大多数强度分布计算模型没有考虑内壁反射的影响,对于不锈钢内壁反应器的强度计算有可能引入高达35%的误差;内壁的漫反射性质明显影响了强度分布的均一性。此外,本文还测量了两个商用三灯管反应器(内径分别为190和150 mm)内部的强度分布,每个反应器含三种灯管布设方式,测量点分别沿着反应器中心轴、半径方向和弧向分布。结果表明,在全部遮挡区域、部分遮挡区域均发现灯管/套管的阴影效应,对弧向平均强度有一定的削弱作用;相邻灯管/套管之间的反射效应对径向平均强度有一定的增强作用;内壁反射效应在灯管靠近内壁布设情况下更为明显。该测试平台的建成为紫外反应器内部结构的优化设计和强度分布计算模型的改进提供了有力支持。 (3)开发了微管流式紫外反应器,相对于常用的准平行光束仪,具有输出紫外强度高、剂量测试准确、处理样品量大、无样品蒸发等显著优点,非常适合于研究紫外强度变化对光化学与光生物反应的影响。进行了KI/KIO3光化学反应实验,发现在0.033-24 mW/cm2的宽广强度范围内,在紫外剂量相同的情况下,该反应与辐照强度无关,证实了微管流式反应器对紫外剂量计量的准确性。随后进行了光生物反应实验,发现在紫外剂量相同的情况下,三种受试微生物(枯草芽孢杆菌菌体、枯草芽孢杆菌芽孢、铜绿假单胞菌)在低强度(0.033 mW/cm2)长时间辐照的情况下,灭活效率要高于高强度(24 mW/cm2)短时间辐照的情况。该意外结果说明用准平行光束仪(辐照强度水平接近0.033 mW/cm2)获得的微生物灭活数据来指导紫外反应器(辐照强度水平接近24 mW/cm2)运行时,将导致较大的误差。 (4)紫外剂量验证是目前紫外反应领域国际研究的热点和难点。本文针对标准生物剂量法存在的问题,研发了可监控生物剂量技术,即通过荧光微探头和可调镇流器对测试过程中的灯管输出进行精确监测和调节,从而在大幅减少受试微生物数量的条件下,仍能测得准确的辐照剂量。结果表明,受试微生物枯草芽孢杆菌芽孢的培养量可以降低218倍,而对紫外敏感、不适用于生物剂量法的大肠杆菌,也可在本技术中得到很好的应用。此外,本文还开发了“探头-模型”结合法,可对紫外反应器的有效辐照剂量进行验证和现场抽检。在水温10-30°C和UVT 85–95%的范围内,分别测量了单灯管、多灯管反应器内多个代表性点位的辐照强度,然后通过加权平均获得“校正因子”,即可将模型计算剂量转换为实际剂量。研究证实,“探头-模型”法的测试结果与生物剂量法保持了很好的一致性。相对于标准生物剂量法,“探头-模型”法不仅提高了测试精度,而且大幅减少了测试时间与费用。 (5)通过三个荧光微探头的组合使用,开发了三参数紫外反应器监测系统,通过计算各探头信号的相关性可以获得灯管输出衰减系数、水体UVT和套管污染系数。研究结果表明,三个参数均可实现在线监测;水温明显影响灯管输出;水体UVT监测数据可由紫外可见分光光度计验证;在配水条件下运行18天后,监测到套管污染系数从1.00下降到0.66。随后,在通入自来水模拟实际运行条件下进行了长达30天的连续监测实验,验证了其良好的应用性能。该监测系统可用于实时调节运行的紫外模块数量、灯管失效报警及启动套管清洗装置。 基于上述开发的优化设计方法、剂量验证和运行监测技术,设计、开发了两套面向二次供水消毒的高效、高可靠性紫外反应器。在安装三参数监测系统后,这两套紫外反应器分别应用于河南省郑州市的两个高层住宅示范小区,已连续运行半年,展示了其安全、节能的良好性能。
英文摘要:       In recently years, ultraviolet (UV) technology has been extensively applied to disinfect municipal drinking water, wastewater, and secondary water supply. High-efficiency and high-security UV disinfection has attracted more and more public attention, which comprises three key parts: 1) optimized design of UV reactors; 2) accurate validation of UV fluence; 3) online monitoring of operational status. This study was carried out on the basis of the above concerns, aiming to provide theoretical and technical supports for the application and dissemination of UV technology in water treatment.(1) A novel micro-fluorescent silica detector (MFSD) was developed, which can instantaneously excite fluorescence upon UV irradiation and then quantify the fluence rate (FR) at any spatial point in a UV reactor by measuring the fluorescence intensity. This detector has distinguished merits of small volume (0.07 mm3), fast response (10–6 s), high chemical and thermal stability, and online monitoring capability in either air or water. Based on the MFSD, an in-situ FR distribution measurement platform was constructed, which can perform practical measurements of the FR distributions in a UV reactor, even at a test point with the nearest distance of only 3 mm from the sleeve. (2) By use of the in-situ measurement platform, the influence of inner-wall reflection on the FR distribution in an annular UV reactor was investigated. The water transmittance (UVT) ranged from 65% to 99%, and the inner-wall materials composed of quartz/aluminum foil, quartz/stainless steel, and quartz/black cloth, with a re?ection coef?cient of 80.5%, 26.1% and 11.1%, respectively. The results indicated that a highly reflective inner wall could cause a marked increase of the average FR in the UV reactor. Because most of the presently used FR distribution models take no account of the inner-wall reflection, the model calculated FR values may have an error of up to 35% in UV reactors with commonly-used stainless steel walls. It was also found that the uniformity of FR distributions was strongly dependent on the diffuse re?ection property of the inner wall. Furthermore, the FR distributions in two practical three-lamp UV reactors (with an inner diameter of 190 and 150 mm, respectively) were determined experimentally. Each reactor had three different lamp configurations, and the test points were set along the axial, radial, and arc directions. The results indicated that a shadowing effect was observed not only in totally-blocked regions but also in partially-blocked regions, which reduced the average FR along the arc direction to some extent. There existed reflections between adjacent lamp/sleeve pairs, which somewhat enhanced the average FR along the axial direction. When the lamps were placed near the reactor wall, the inner-wall re?ection exhibited a strong impact on the FR distributions. This measurement platform provides a strong support for the optimized design of UV reactors and the improvement of FR distribution models.(3) A mini-tubular fluidic (MTF) UV reactor was developed, which has distinct merits of high UV irradiance, accurate fluence quantification, large sample volume, and no sample evaporation, as compared to the commonly-used quasi-collimated beam apparatus (CBA).
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35193
Appears in Collections:环境水质学国家重点实验室_学位论文

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Recommended Citation:
李梦凯. 紫外反应器的优化设计方法、剂量验证和运行监测[D]. 北京. 中国科学院研究生院. 2013.
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