Source characterization studies at the Paraho semiworks oil shale retort. [Redistribution of trace and major elements

Abstract

In order to determine the redistribution of trace and major elements and species during aboveground oil shale retorting, a comprehensive program was carried out for the sampling and analysis of feedstock, products, effluents, and ambient particulates from the Paraho Semiworks Retort. Samples were obtained during two periods in 1977 when the retort was operating in the direct mode. The data were used to construct mass balances for 31 trace and major elements in various effluents, including the offgas. The computed mass balances indicated that approx. 1% or greater fractions of the As, Co, Hg, N, Ni, S, and Se were released during retorting and redistributed to the product oil, retort water, or product offgas. The fraction released for these seven elements ranged from approx. 1% for Co and Ni to 50 to 60% for Hg and N. Approximately 20% of the S and 5% each of the As and Se were released. Ambient aerosols were found to be elevated near the retorting facility and associated crushing and retorted shale disposal sites. Approximately 50% of these particles were in the respirable range (< 5 ..mu..m). The elevated dust loadings are presented very local, as indicated by relatively low aerosol loadings atmore » background sites 100 to 200 m away. State-of-the-art dust control measures were not employed. 15 figures, 19 tables.« less