Results of studies from a project sponsored by the Department of Energy (DOE), Morgantown Energy Technology Center (METC), are reported. The primary objective of these studies was to develop a catalyst which converts sulfur in coal tars to a form (such as H/sub 2/S) which can be removed by a hot gas desulfurization process being developed by DOE/METC and also converts the tars to compounds that cannot crack and deposit coke on the electrodes of a molten carbonate fuel cell (MCFC). The system for tar destruction would operate in conjunction with the desulfurization process. Results of a literature search and experimental tests are presented. Fifteen different catalysts were evaluated in the experimental tests. The effects of temperature, pressure, and residence time on tar conversion were evaluated. Acid cracking catalysts, in a particular low-sodium type Y zeolite (LZ-Y82) and hydrocracking catalysts based on Y-zeolite, were superior to other catalysts tested. In four hour screening tests, average tar conversions with these catalysts for four different tar samples ranged from 65 to 75% based on total tar. Average sulfur conversion ranged from 86 to 90%. Results of regeneration tests are presented. These tests show that LZ-Y82 is regenerable under mild regeneration conditions. The rate of permanent loss of catalyst activity was too low to identify in the regeneration tests. Catalyst makeup rates based on literature values are presented for estimation of catalyst costs. 30 refs., 14 figs., 26 tabs.