New Ways for the Advanced Quality Control of Liquefied Natural Gas

[Abstract] Currently, gas chromatography is the most common analytical technique for natural gas (NG) analysis as it offers very precise results, with very low limits of detection and quantification. However, it has several drawbacks, such as low turnaround times and high cost per analysis, as well as difficulties for on-line implementation. With NG applications rising, mostly thanks to its reduced gaseous emissions in comparison with other fossil fuels, the necessity for more versatile, fast, and economic analytical methods has augmented. This work summarizes the latest advances to determine the composition and physico-chemical properties of regasified liquid natural gas, focusing on infrared spectroscopy-based techniques, as well as on data processing (chemometric techniques), necessary to obtain adequate predictions of NG properties.Part of this work was performed under the EMPIR 16ENG09 project ‘Metrological support for LNG and LBG as transport fuel (LNG III)’. This project has received funding from the EMPIR programme co-financed by the Participant States and from the European Union’s Horizon 2020 Research and Innovation programme. Mestrelab, Reganosa and Naturgy are acknowledged for hiring the services of the Group of Applied Analytical Chemistry for FTIR method development. The Program “Consolidación e Estructuración de Unidades de Investigación Competitivas” of the Galician Government (Xunta de Galicia) is also acknowledged (Grant ED431C 2021/56).Xunta de Galicia; ED431C 2021/5

Weathering-Independent Differentiation of Microplastic Polymers by Reflectance IR Spectrometry and Pattern Recognition

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] The presence and effects of microplastics in the environment is being continuously studied, so the need for a reliable approach to ascertain the polymer/s constituting them has increased. To characterize them, infrared (IR) spectrometry is commonly applied, either reflectance or attenuated total reflectance (ATR). A common problem when considering field samples is their weathering and biofouling, which modify their spectra. Hence, relying on spectral matching between the unknown spectrum and spectral databases is largely defective. In this paper, the use of IR spectra combined with pattern recognition techniques (principal components analysis, classification and regression trees and support vector classification) is explored first time to identify a collection of typical polymers regardless of their ageing. Results show that it is possible to identify them using a reduced suite of spectral wavenumbers with coherent chemical meaning. The models were validated using two datasets containing artificially weathered polymers and field samples.This work was supported by the EU Horizon2020-JPI Oceans Project “LAnd-Based Solutions for PLAstics in the Sea” (Grant No. 101003954, LABPLAS), and the “Integrated approach on the fate of MicroPlastics towards healthy marine ecosystems” (MicroplastiX, Grant PCI2020-112145, supported by the JPI Oceans Program and by Spanish Government, MCIN/AEI/10.13039/501100011033 and the European Union “Next Generation EU/PRTR program”). The Galician Government (‘Xunta of Galicia’) is acknowledged for its support to the QANAP group (Programa de Consolidación y Estructuración de Unidades de Investigación Competitiva. Ref. ED431C 2021/56). Funding for open Access charge: Universidade da Coruña/CISUGXunta de Galicia; ED431C 2021/5