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|Keywords: ||氣相層析;非甲烷總碳氫;有害空氣污染物;gas chromatography;non-methane hydrocarbons;hazardous air pollutants|
|Issue Date: ||2015-09-23 10:50:10 (UTC+8)|
|Abstract: ||本研究針對煙道氣中的揮發性有機化合物(volatile organic compounds, VOCs)，以氣相層析儀搭配火焰離子偵測器(gas chromatography/flame ionization detector, GC-FID)，開發兩種連續自動監測系統(continuous emission monitoring systems, CEMS)。|
第一部分的CEMS方法開發，係針對煙道氣中的非甲烷總碳氫化合物(total non-methane hydrocarbon, tNMHC)。以填充管柱(packed columns)與逆吹設計(back-flush)，在恆溫下將甲烷與其他高沸點之VOC分離，可依序獲得總碳氫(total hydrocarbon, THCs)與甲烷濃度，再以扣除方式獲得tNMHC濃度，每次分析僅需2.5分鐘。逆吹的設計目的在於可避免高沸點物質在恆溫150℃的分析管柱中殘留；在系統數據方面：多點檢量線之線性常數(R2)達0.999，精密度(RSD)可在1.07%以下。
而本研究第二部分，則係針對煙道氣中13種有害空氣污染物(hazardous air pollutants, HAPs)，使用一不具極性之60公尺毛細管柱進行分離，且運用逆吹將煙道內可能存在高沸點、黏滯性物種排出分析管柱；相關數據方面：多點校正相關係數R2在0.995以上；回收率可達85%以上；精密度RSD值則在4.09%以下；偵測極限0.06 ppm以下。
;Two gas chromatographic (GC) methods equipped with flame ionization detection (FID) were developed in this study to serve as continuous emission monitoring systems (CEMS) to measure volatile organic compounds (VOCs) in stack gas.
The first method of CEMS is aimed at measuring the total amounts of non-methane hydrocarbons (dubbed tNMHCs) in stack gas. The method adopted packed columns and the back-flush design at isothermal oven temperature to separate methane from higher boiling VOCs. Within each analysis of 2.5 minutes, the concentrations of total hydrocarbons (THCs) and methane were alternatively obtained. Subsequently, the concentration of tNMHCs was obtained by subtracting the methane concentration from the THC concentration. The back-flush mechanism prevented high-boiling residues from accumulating in the analytical column at the isothermal oven temperature of 150℃, which is a highly desirable feature operated in CEMS mode. The test of quality assurance gave rise to the linearity of 0.999 (R2) from multi-point calibration and the precision better than 1.07% for tNNMHCs.
The second method of CEMS targets 13 individual VOCs in stack gas, which are categorized as hazardous air pollutants (HAPs) due to their toxicity. A 60 m long capillary column of 100% polydimethylsiloxane and an optimized temperature program was employed for base-line separation of the 13 target compounds. For CEMS consideration, back-flush was adopted to flush out high-boiling residues within each analysis. The quality assurance test gave rise to the linearity (R2) of better than 0.995, recovery higher than 85%, precision better than 4.09% and detection limits lower than 0.06 ppm.
Both of the two CEMS methods were also tested in the factories for robustness and applicability. For the tNMHC method, inter-comparison with an existing method (NIEA 723.73B) demonstrated that our tNMHC method out-performed the existing method by more accurately measure methane in stack gas from a semiconductor factory.
|Appears in Collections:||[化學研究所] 博碩士論文|
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