Determination of volatile organic compounds in processes water samples by GC-FID

Identifier:  TFG:1377

Handle: https://hdl.handle.net/20.500.11797/TFG1377

Authors:  Solsona Roca, Sergi

Abstract:
Nowadays, Repsol Chemistry Industrial Complex produces a wide assortment of oil products, among them monopropylene glicol, dipropylene glicol and tripropylene glicol. These compounds are produced in the reaction between processed water and propylene oxide. In order to control organic volatile compounds in water, some gas chromatography analysis are done. Moreover with GC analysis they can control the presence of contamination sources in a plant’s equipment. The goal of this project is the optimization of an existing gas chromatography method to determine volatile organic compounds in water samples from the glicols plant. Therefore, a new gas chromatography method has been developed without adding any standard intern in the pre-treatment sample. A second goal of this project is to validate the new method and compare the quality parameters with and without adding a standard intern. Moreover F-02, F-14, H-07 and H-08 samples were analysed using the new method with and without adding standard intern. The repeatability and intermediate precision results that were obtained show that it is not necessary to use a standard intern to determine volatile organic compounds in processed water samples by GC-FID. Moreover, it should also be mentioned that toluene, ethylbenzene and styrene have poor repeatability. Besides, the regressions obtained from toluene, ethylbenzene and styrene do not predict the concentration values of the mixed standards. If the calibration standards are carried out only by adding these compounds to water, good prediction values are obtained. This means that there is a matrix effect due to some interference in the prepared standards or aromatic compounds which are more soluble in an organic environment. The sum of the concentrations of DPG and TPG isomers in the samples does not correspond exactly to the concentrations of DPG and TPG as the regression lines have been built by distribution of areas. The predicted values of the samples without adding the internal standard conform to values calculated in the chemical plant. Finally good recoveries where achieved.