Feedstock Impurities – How to Find Them, If It Is Not Known What They Are?

Recently, a number of new feed sources for steam cracking operators have become viable, ranging from ethane extracted from shale gas to the integration of petrochemical and refining operations. The issues that are encountered when looking at new feedstock possibilities are the impurities, both known and unknown, and how to establish the quality of the feed. The largest challenges surround what impurities to look for, how to sample to ensure the impurities are preserved, how to analyze limited sample volumes, and how to identify misleading results. An advanced characterization program was designed and implemented to identify the chemical nature of the contaminants present in different feeds and intermediate process streams. This paper discuss the analytical program, interpretation of results, and sampling issues faced while analyzing samples of unknown composition and impurity.