In a previous study (1), Foster Wheeler made an assessment of modular IGCC power systems employing Texaco entrained flow gasification of Illinois No. 6 coal. In that study, five case studies were developed in order to compare the relative performance and economics of air vs. oxygen blown gasification and high temperature vs. low temperature gas cleanup. As a supplemental study, two additional IGCC design cases were developed as alternate to the original Case 2 and Case 3 configurations. The objective of the Case 2 alternate study was to assess the potential of zinc titanate in place of zinc ferrite. Compared to zinc ferrite, the zinc titanate system offered the following potential advantages: Does not require steam conditioning of the feed gas to avoid carbon formation; does not require reductive regeneration and the corresponding use of fuel gas; operates at higher temperature, about 1350{degree}F; and has a longer projected sorbent life. The objective of the alternate Case 3 study was to determine the economic impact of producing sulfuric acid, instead of elemental sulfur, as the by-product from high temperature desulfurization using zinc ferrite. Sulfur recovery as by-product sulfuric acid therefore offered the potential for reducing both the capital and operating costs. 6 refs., 5 figs., 15 tabs.