摘要
随着超低排放改造的推进,工业排放烟气中可过滤颗粒物(FPM)的排放质量浓度快速下降,但是烟气中可凝结颗粒物(CPM)的排放问题却日益突出。现有的CPM测量方法主要基于手工采样和实验室分析,存在干扰气体影响、壁面损失等局限性。为了实现CPM排放的监管,亟需开发准确有效的在线监测技术。本研究设计并开发了一种基于控制冷凝-稀释干燥法的CPM在线监测及质控装置,并在典型固定污染源行业进行了示范应用。该装置通过模拟工业烟羽中CPM冷凝形成颗粒物及其在大气中的扩散干燥过程,采用β-衰减传感器对干燥后的颗粒物进行质量浓度监测,并通过一系列清洗与质量控制措施减少测量误差。实验室内的CPM校准与性能评估结果显示该装置测量误差小于5%,具有良好的稳定性;在湖州和北京等地的典型生物质锅炉、燃煤锅炉和石油催化裂解装置烟气现场测试表明,该装置能够提供24 h连续的CPM质量浓度变化数据,有效反映了烟气中CPM质量浓度的变化。在线监测质量浓度与EPA Method 202手工采样结果相关系数达到0.965(p<0.001),趋势高度一致但数值存在差异。该差异证实了在线装置有效排除了SO_(2)吸收带来的干扰偏差,提升了复杂工况下的测量准确性。CPM在线质量浓度监测技术的开发为工业烟气监管提供了重要的数据保障,有助于超低排放政策的进一步实施。
Objective With the implementation of ultra-low emission standards,the concentration of filterable particulate matter(FPM)from industrial flue gas has been substantially reduced,whereas condensable particulate matter(CPM)is becoming a dominant contributor to stationary source emissions and ambient PM_(2.5).Conventional CPM measurement relies on manual sampling and laboratory analysis(e.g.,EPA Method 202).However,this approach is limited by positive artifacts(gas absorption),wall losses,low time resolution,and heavy workload,failing to meet the demands of refined air quality management.To address these limitations,this study developed an online continuous CPM monitoring and quality-control device for stationary sources based on a controlled condensation-dilution-drying approach,and systematically evaluated its performance.Methods The device comprises a thermostatic separation unit,a measurement unit,and an online quality control unit.Flue gas is isokinetically sampled and cooled in a hydrophobic condenser to collect CPM as condensate,which is rapidly transferred to minimize contact with soluble gases.An aerosol generator and drying section convert the condensate into dry particles representing total particulate matter(TPM),whose mass is quantified by aβ-attenuation sensor.The CPM concentration is then derived by subtracting the FPM concentration obtained from the continuous emission monitoring system(CEMS).The quality control unit ensures reliability through automatic temperature control,multi-stage cleaning,and blank control.The performance of the device was assessed through laboratory calibration with ammonium bisulfate solutions(1–50 mg/m^(3))and flue-gas simulation experiments.Specifically,a gas-interference test with 5μmol/mol SO_(2) was conducted to verify resistance to gas-absorption artifacts,followed by parallel field measurements at typical stationary sources.Results and Discussion Laboratory calibration results for the device demonstrate a robust linear response(R=0.953)within the concentration range of 1–50 mg/m^(3),and the deviation from the true values for all measurement points is within±5%.In flue-gas simulations,the measurement errors remain within 10%,and a 24-h continuous run yielded a relative standard deviation(RSD)below 1.77%.Repeated measurements over six days at a nominal concentration of 10 mg/m^(3) showed high stability(mean:10.05±0.28 mg/m^(3)).Crucially,gas-absorption experiments revealed that SO_(2)-induced positive bias(1.6 mg/m^(3))in the online system is significantly lower than that of manual Method 202(5.5 mg/m^(3)),thus confirming the effectiveness of rapid condensate transfer.Field applications at three industrial sources generate continuous 24-h CPM profiles,which effectively capture emission fluctuations and operational changes.The online CPM data show strong agreement with the results of manual measurements for both inorganic-dominated and organic-rich sources(R=0.965,p<0.001).The high-resolution data further reveal the diurnal variation of CPM from a biomass boiler and indicate potential links between CPM formation and desulfurization/denitrification processes.Overall,the developed device provides accurate,stable,and composition-independent online CPM monitoring,offering critical data support for ultra-low emission control.Conclusion In conclusion,this study developed an online monitoring and quality control device for CPM,addressing the limitations of traditional manual sampling and laboratory analysis.By simulating the condensation process and utilizingβ-attenuation sensing,the system enables the transition from discontinuous measurement to continuous online monitoring.The integrated quality control measures of the device,especially automatic cleaning and calibration,minimize errors caused by gas absorption and wall losses.Field applications verify that the device provides 24-h continuous data consistent with EPA Method 202,capturing dynamic concentration changes in flue gas.This technology provides robust data support for stationary source supervision and the implementation of ultra-low emission policies.
作者
王欢韬
续鹏
陈源正
王军
刘通浩
李庆
WANG Huantao;XU Peng;CHEN Yuanzheng;WANG Jun;LIU Tonghao;LI Qing(Department of Environmental Science and Engineering,Fudan University,Shanghai 200438,China;Institute of Atmospheric Environment,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;National Environmental Protection Environmental Monitoring Quality Control Key Laboratory,China Environmental Monitoring General Station,Beijing 100012,China)
出处
《大气与环境光学学报》
2026年第1期151-164,共14页
Journal of Atmospheric and Environmental Optics
基金
科技部重点研发计划项目(2022YFC3700501)
国家自然科学基金委员会交叉科学部优青项目(T2122006)。
关键词
可凝结颗粒物
烟气监测技术
在线监测设备
固定源
测量质控技术
condensable particulate matter
flue gas monitoring technology
online monitoring equipment
stationary source
measurement quality control technology
