Development of a cloud condensation nuclei (CCN) counter using a laser and charge-coupled device (CCD) camera

A continuous flow streamwise thermal gradient cloud condensation nuclei (CCN) counter with an aerosol focusing and a laser-charge-coupled device (CCD) camera detector system was developed here. The counting performance of the laser-CCD camera detector system was evaluated by comparing its measured number concentrations with those measured with a condensation particle counter (CPC) using polystyrene latex (PSL) and NaCl particles of varying sizes. The CCD camera parameters (e.g. brightness, gain, gamma, and exposure time) were optimized to detect moving particles in the sensing volume and to provide the best image to count them. The CCN counter worked well in the particle number concentration range of 0.6–8000 #·cm^-3 and the minimum detectable size was found to be 0.5 μm. The supersaturation in the CCN counter with varying temperature difference was determined by using size-selected sodium chloride particles based on K?hler equation. The developed CCN counter was applied to investigate CCN activity of atmospheric ultrafine particles at 0.5% supersaturation. Data showed that CCN activity increased with increasing particle size and that the higher CCN activation for ultrafine particles occurred in the afternoon, suggesting the significant existence of hygroscopic or soluble species in photochemically-produced ultrafine particles.     

高污染下云凝结核对雨、雾滴谱的影响

利用气候基准站、云凝结核计数器、雾滴谱仪和雨滴谱仪等观测资料,分析威宁污染时期云凝结核（CCN）对雨雾滴谱的影响. 结果表明：观测期间威宁CCN数浓度很高,S=0.2%、0.4%、0.6%和0.8%时的平均CCN浓度分别为2884、8003、10470、11685cm^-3,与部分重污染城市相当;CCN有明显的日变化特征,分别在12：00、16：00和20：00出现峰值,与居民生活排放、火电源排放、湍流交换和气象条件等有关;利用N=CS^k式拟合威宁CCN活化谱,平均拟合参数C=14288cm^-3,k=0.8,表明该地属典型大陆型核谱;威宁冬季云层薄、云顶低的云系特点提供了宏观天气背景,高浓度CCN是导致此次雨、雾过程弱,滴谱窄的重要微观条件.     

挥发性有机物(VOCS)活性炭吸附回收技术综述

随着我国经济建设的发展,各类有机溶剂的应用越来越广,有机废气的排放量也随之逐年增加,其所带来的空气污染等环境问题已经引起全世界的关注。过去,研究人员主要致力于开发高效的VOCs控制技术。随着我国建立可持续社会目标的提出,越来越多的人开始关注经济有效的VOCs回收方法。本文重点介绍了活性炭吸附回收VOCs的工艺现状和研究进展,并预测了VOCs分离回收技术的发展趋势。     

制冷技术革命与冷凝法油气回收技术的发展

介绍了20世纪后期制冷技术革命性的进步,及其对冷凝法油气回收技术发展的推进作用,分析了冷凝法油气回收技术的优势和对生产厂家的要求。     

Evolution in physiochemical and cloud condensation nuclei activation properties of crop residue burning particles during photochemical aging

As a main form of biomass burning in agricultural countries, crop residue burning is a significant source of atmospheric fine particles. In this study, the aging of particles emitted from the burning of four major crop residues in China was investigated in a smog chamber.The particle size distribution, chemical composition and cloud condensation nuclei(CCN)activity were simultaneously measured. The properties of crop residue burning particles varied substantially among different fuel types. During aging, the particle size and mass concentration increased substantially, suggesting condensational growth by formation of secondary aerosols. The particle composition was dominated by organics. Aging resulted in considerable enhancement of organics and inorganics, with enhancement ratios of 1.24–1.44 and 1.33–1.76 respectively, as well as a continuous increase in the oxidation level of organics. Elevated CCN activity was observed during aging, with the hygroscopicity parameter κ varying from 0.16 to 0.34 for fresh particles and 0.19 to 0.40 for aged particles.Based on the volume mixing rule, the hygroscopicity parameter of organic components(κorg) was derived. κorgexhibited an increasing tendency with aging, which was generally consistent with the tendency of the O:C ratio, indicating that the oxidation level was related to the hygroscopicity and CCN activity of organic aerosols from crop residue burning. Our results indicated that photochemical aging could significantly impact the CCN activation of crop burning aerosols, not only by the production of secondary aerosols, but also by enhancing the hygroscopicity of organic components, thereby contributing to the aerosol indirect climate forcing.     

二级膜分离—冷凝—吸附工艺处理石化罐区废气

采用二级膜分离—冷凝—变压吸附工艺回收处理含有高浓度挥发性有机物和苯系物的炼厂罐区外排“呼吸气”。结果表明,进气的非甲烷总烃质量浓度范围41 000~182 000 mg/m³,进气中苯、甲苯和二甲苯的质量浓度分别为400~1 400 mg/m³,150~1 600 mg/m³,300~2 100 mg/m³时,尾气中非甲烷总烃质量浓度始终低于80 mg/m³,去除率均高于99.9%,苯、甲苯和二甲苯的去除率分别为99.6%、99.6%和99.8%。抗冲击负荷实验将进气量提高50%,尾气中非甲烷总烃质量浓度仍低于80 mg/m³。二级膜单元可以高效浓缩轻烃,既回收获得可燃气,又解决了轻烃积累所造成的尾气超标难题。     

缩合-催化氧化-生化工艺处理酚醛树脂酚类废水研究

介绍了“缩合-催化氧化-生化处理”工艺处理酚醛树脂生产中产生的酚类废水的实验研究和工程实例.实验数据表明,高浓度的酚醛树脂生产废水中含有高浓度苯酚,采取该工艺处理后,能显著地降解废水中的酚类,外排废水COD、BOD5、苯酚、甲醛浓度符合《合成树脂工业污染物排放标准》(GB 31572-2015)标准》.该工艺具有工程投资和运行费用低,处理效果稳定等特点,能广泛应用于酚醛树脂工业生产废水的治理,具有较好的推广价值.     

湿法脱硫后烟气中SO3/硫酸雾测试方法的试验

在自行设计和搭建的模拟湿法脱硫烟气系统中,研究了基于控制冷凝法原理的SO_3/硫酸雾采集装置对湿法脱硫后SO_3/硫酸雾的捕集性能,重点考察了螺旋管与石英棉冷凝温度、采样枪温度、采样流量、采样时间和SO_3/硫酸雾质量浓度对SO_3/硫酸雾捕集性能的影响。结果表明,在研究范围内,湿法脱硫后SO_3/硫酸雾采集装置优化的操作参数为:螺旋管及石英棉冷凝温度95℃,采样枪温度280℃,采样流量17 L/min,采样时间30 min。SO_3/硫酸雾质量浓度较高时,螺旋冷凝管对SO_3/硫酸雾的捕集起主要作用,其捕集的SO_3/硫酸雾比例在75.8%~80.8%,远高于螺旋冷凝管与石英棉捕集SO_3/硫酸雾的比例;SO_3/硫酸雾质量浓度较低(约1mg/m3)时,采样枪对SO_3/硫酸雾的捕集起主要作用,其捕集SO_3/硫酸雾的比例大于50%。     

重量法和冷凝法测量烟气含湿量计算公式的改进

本文对现有文献中用重量法和冷凝法测量烟气含湿量的计算公式进行了改进，使改进后的公式更准确、适用。     

雾化电晕净化烹调油烟技术

对雾化电晕放电极雾化过程、荷电液滴的捕集原理、自清洗作用进行探讨,在相同电压下雾化负电晕放电电流高于干式负电晕放电电流,极间大量荷电液滴具有很高的荷质比,并高速向极板驱进,对烟尘具有静电凝并和动力凝并除尘作用,具有高效净化油烟、自清洗极板的功能,此项净化烹调油烟的新技术,优于传统油烟净化技术,具有很好的应用价值和前景.