Catalyst Aging Evaluation with Exposure to 0.06 and 0.11 Percent Phosphorus Oils Using the FOCAS® Burner System

This study was performed by the Department of Emissions Research at Southwest Research Institute (SwRI^®) in response to a request from the ASTM OPEST II (Oil Protection of Emissions Systems Test) Task Force. The objective of the study was to develop and demonstrate a preliminary catalyst oil-poisoning aging and screening procedure to evaluate and differentiate the effect of oils with varying levels of phosphorus on catalyst performance. The ultimate objective was to begin the groundwork for creating a procedure that could demonstrate the impact of engine oil formulations on catalyst performance. The oils used in this program were fully formulated oils referred to as ‘OilA’ and ‘OilB.’ OilA contained 0.11 and OilB contained 0.06 weight percent phosphorus, with both containing the same levels of ash-forming compounds. The procedure developed used a gasoline-fueled burner with an isolated oil injection subsystem. The system precisely controlled the consumption rate and oxidation state of the oil (unburned, partially burned, or fully burned) and catalyst aging cycle. This patent pending burner/oil injection system, developed by SwRI, is called the FOCAS^® system.

There were four main parts to the initial study. The first part was to develop an aging cycle that included a variety of operating modes, including a cold-start simulation. The second part was to age several catalysts using this cycle and two oils that have field proven performance differences [SAE 961898]. In the third part, the performance of each FOCAS^® aged catalyst was evaluated to assess the impact of the two oils. The fourth part was to analyze the mass distribution and ratio of the oil deposits of the aged catalysts, and to compare those distributions to field aged catalysts. This paper presents data from the aging and evaluation of four catalysts and two oils, aged to 280 hours with 7.57 L of oil, and 560 hours with 15.6 L of oil. Information on the aging cycle will be presented in the paper. The performance results of each catalyst and the mass distribution of deposits showed very good correlation to the field data provided.