Analysis of plastic recycling products by expert systems

An automated method for monitoring a polyethylene recycling process has been developed. The products of catalyzed polyethylene cracking are alkanes, monounsaturated alkenes (monoene) and dienes, which were analyzed by gas chromatog-raphy-mass spectrometry. Three expert systems, a knowledge based expert system, a univariate rule building expert system and a fuzzy multivariate expert system, were developed and evaluated for their ability to correctly classify products of polyethylene cracking by their degree of unsaturation. Two test sets were used in the evaluation. One contained spectra from a mass spectral library. The second was a collected set of hydrocarbon standards. On both test sets, the rule building expert systems performed better than the knowledge based expert system. The chemometric detectors were effective for mathematically resolving chromatograms by chemical functionality.