An experimental program has been conducted to measure and compare the efficiency of two stack sampling systems to collect vanadium-bearing particulate emissions in flue gas. One sampling system was EPA's Method 5, the other was developed by Exxon Research and Engineering Company for specialized in-house studies. To evaluate collection efficiency, an extensive factorial study was carried out in a 50 hp four-pass firetube boiler burning typical residual fuel oils. In each test the sampling systems were operated simultaneously in the stack to collect the vanadium-bearing particulate emissions. Three residual fuel oils were tested: two Venezuelan (359 and 149 ppm V) and one Arabian (39 ppm V). A vanadium balance was established for each experiment by inventorying both the particulate emissions and the particulates remaining in the boiler. Test variables, in addition to the sampling systems and fuel oils, also included two combustion residence times and two sampling probe locations. The results of the study show that vanadium collection efficiency depends on two variables: combustion residence time and sampling system. For both systems efficiency decreases as combustionresidence time increases, which results in a particulate size distribution shift to the submicron range. Where particulate emissions are in the coarse size range, collection efficiency in both sampling systems is almost quantitative. The oxidation states of vanadium in fuel oil emissions are briefly discussed.

"April 1976". Sponsored by U.S. Environmental Protection Agency "Project Officer: James L. Cheney". Includes bibliographical references (p. 99-115). "EPA-600/2-76-096".