MEASUREMENT & TESTING
response factors to benzene were determined experimentally, then values were compared with the theoretical relative response factors obtained using the equivalent number theory.
The analytical system’s measurement of liquid samples was then tested using a P&T sampling system and a standard diluted in water with concentration of around 4µg/L. Prior to the analysis, the system was calibrated with a TO14 gas standard. The VOCs concentrations in liquid were determined given that 100% of VOCs contained in the water sample could be extracted and preconcentrated into the sampling trap.
Industrial air monitoring waste water plant
A real-life application of this unique solution is described hereafter; The Jiangsu province is an important industrial region in China. Industrial emissions lead to the release of VOCs into the atmosphere. VOCs are dangerous pollutants and can fi nd their way into groundwater used for drinking purpose because of their high-water solubility and polarity. These compounds are known to have adverse effects on human and environmental health and also contribute signifi cantly to the formation of ozone.
In order to ensure drinking water safety, the Jiangsu Provincial Department of Ecology and Environment released in 2018 a “Three-Year Development Plan”. This action plan aims to signifi cantly improve VOC groundwater contamination control and treatment. The analyses of VOCs in water require preconcentration of the analytes. The most common sample- enrichment methods for determining VOCs in water are P&T, headspace (HS) and solid-phase microextraction (SPME).
The system used in this study is an auto-GC-FID system with P&T technology for the determination of the analytes included in the US EPA 502.2 method. The main goal was to improve process effi ciency and control using automatic on-line continuous monitoring.
Tests were performed using a TO14 cylinder (CPE-10010) and PAMS cylinder (CPC-03287) containing VOCs at 100 ppb for each compound (+/-2% of accuracy). Liquid samples were also used: a 502.2 liquid standard with a concentration of 200ng/mL diluted in water to reach 4µg/L and benzene and toluene diluted in water at 4µg/L. A benzene permeation tube with permeation rate of 11.5ng/min at 40°C was used for the internal calibration of instruments and response factor calculations, in accordance with the requirement of the ISO:17025 for benzene calibration. The relative
A total recovery of mass injected (4µg/L) was obtained for most VOCs such as benzene (4.2µg/L), toluene (4.5µg/L), or trichloroethene (3.8µg/L). The results indicate that calibrations can be performed using gas standards, which makes the system preparation much simpler. Also, for very volatile compound, the liquid standard preparation is diffi cult, as these compounds may become vaporized before the analysis. Therefore, gas calibration may be considered more reliable for such compounds.
A water sample containing benzene and toluene at 4µg/L was diluted to various concentrations to test the linearity of the response. Also, a gaseous dilution system equipped with a Mass Flow Controller (airmoCAL D-MFC, Chromatotec, France) was used to achieve four points of different concentrations in a range between 0 and 100ng/L. The detector gave an excellent correlation between their response (RSD < 2%) and the concentration (R2=1).
The results obtained for the online quantifi cation of 59 VOCs in 60min without memory effects using an auto-TDGC-FID analytical system in both gaseous and liquid samples when using a P&T sampling system are excellent and validated by many existing industrial customers. A quadrupole mass spectrometer can be coupled to the system to identify unknown compounds, either after the chromatographic column or from direct measurement, thus increasing the number of molecules analyzed to at least 123. The system used is fully automatic, linear, precise down to ppt levels and very stable. All generators needed for the continuous operation of the gas chromatograph are integrated into the cylinder-free analytical system. The system requires little maintenance because all cleaning procedures are performed automatically. Only the deionized water level in the hydrogen generator has to be checked monthly. The measurement system performance evaluation is completed with internal calibration using NIST-traceable permeation tube technology to provide automatic data validation.
The system automatically quantifi es VOCs in water, including BTEX, to stay in compliance with wastewater discharge
Author Contact Details Franck Amiet – President,Chromatotec Group • 15 rue d’Artiguelongue Saint-Antoine 33240 Val de Virvée France • Tel: 05 57 94 06 26 • Email:
info@chromatotec.com • Web:
www.chromatotec.com
27
AirmoVOC WMS
regulations from environmental protection agencies by taking corrective actions if maximum limits are exceeded. This solution will allow improving the ground water quality monitoring network through effective and comprehensive drinking water source monitoring using early warning systems and providing emergency backup water sources in Shuoxiang Lake, Guannan County, Lianyungang City.
The autonomous airmoVOC WMS can be also used in water markets for food processing, pharmaceutical industries, cosmetics and perfumeries. It can also be used for monitoring drinking water (beverages or source water), surfaces and wastewater as well as other types of liquid foods (milk, soda, wine, spirits, etc.) and organic liquids.
How does PAT fi t successfully into the overall concept of effi cient petrochemical plant operation
For this year’s PEFTEC Process Conference taking place virtually on the 24th & 25th November we have put together a variety of presentations and keynote lectures combining expertise from academia, instrument manufacturers, system integrators and industrial end users to cover the complete scope of process analytical technology (PAT) from sampling, calibration, instrumentation to analysis of big data using inferential analysis.
The aim of the presentations is to give the audience the opportunity to learn about cutting-edge research within the CPACT research network and also novel instrumentation which has made the transition from research to applications in the fi eld of alternative hydrogen production where a very high sensitivity is required. We also cover the very foundations of successful PAT with a presentation of robust gas sampling technology for emissions monitoring using a traditional process GC. Reliable sampling technology is crucial for best process analyser system performance.
New smart analysers have the potential to further shape the future landscape of PAT and we will provide examples of how these innovative systems can be used for process analytics and quality assurance.
Edo Johann Becker, PAT Technical Consultant
Finally, practitioners in the petrochemical industry will demonstrate how on-line analysis and real time characterization can assist them in catalyst development, pilot plant operation and driving the sustainability agenda on a main plant-covering the complete industrial development cycle from basic science to effi cient main plant operation.
The talks are aimed at anyone working or aspiring to become engaged in the fi eld of PAT and looking to broaden his or her views on technologies available, discover new techniques useful in PAT and how PAT can fi t into the overall concept of effi cient petrochemical plant operation. Therefore, the presentations will not only benefi t analyser engineers, but also petrochemical plant operators and instrument manufacturers, from entrance level engineers to plant managers and decision makers alike.
To register and view the full conference programme for PEFTEC please go to
www.peftec.com For More Info, email:
56475pr@reply-direct.com
email: For More Info, email: email:
OCTOBER / NOVEMBER
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