Fast online emission monitoring of volatile organic compounds (VOC) in wastewater and product streams (using stripping with direct steam injection)

摘要

Open-loop stripping analysis (also referred to as dynamic headspace) is a very flexible and robust technology for online monitoring of volatile organic compounds in wastewater or coolant. However, the quality and reliability of the analytical results depend strongly on the temperature during the stripping process. Hence, the careful and constant heating of the liquid phase inside the stripping column is a critical parameter. In addition, this stripping at high temperatures extends the spectrum of traceable organics to less volatile and more polar compounds with detection limits down to the ppm-level. This paper presents a novel and promising approach for fast, efficient, and constant heating by the direct injection of process steam into the strip medium. The performance of the system is demonstrated for temperatures up to 75 °C and traces of various hydrocarbons in water (e.g., tetrahydrofuran, methanol, 1-propanol, n-butanol, ethylbenzene).