Volatile fingerprint and multivariate odor evaluation of gasification slag and natural coal resources using gas chromatography–ion mobility spectrometry and gas chromatography–mass spectrometry characterization

Natural coal can be produced via desulfurization, decarbonization, and other processes under appropriate pressure and temperature conditions, enabling it to react with gasification agents and produce gas. Fine slag and coarse slag are both by-products of the entrained-flow gasifier and may contain a large amount of carbonaceous residue. To explore the optimization of the gasification process, coal upgrading, and adulteration identification, qualitative and semi-quantitative characterizations of the volatile organic components in gasification slag and natural coals were carried out using Gas chromatography–ion mobility spectrometry (GC–IMS) and gas chromatography–mass spectrometry (GC–MS). Fingerprint spectra were generated to illustrate the volatile differences and specificities. A total of 51 kinds of volatiles were analyzed using a rapid and non-destructive detection method under ambient conditions by GC–IMS method. GC–MS, acting as a supplementary identification method, detected a total of 40 volatile compounds, among which alkanes were in the majority. Characteristic markers were explored to achieve the accurate differentiation of volatiles from natural coal and gasification slag samples. Multivariate analyses, including heatmap, hierarchical cluster analysis (HCA), principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discrimination analysis (OPLS-DA), were conducted to discriminate the odor of natural coal and gasification slag samples. This study deepens the understanding of volatile distribution and lays the foundation for the development of gasification technology and adulteration monitoring.