BENCH-SCALE DEMONSTRATION OF HOT-GAS DESULFURIZATION TECHNOLOGY

The Direct Sulfur Recovery Process (DSRP) is a one- or two-stage catalytic reduction process for efficiently converting to elemental sulfur up to 98 percent or more of the sulfur dioxide (SO{sub 2}) contained in the regeneration offgas streams produced in advanced integrated gasification combined cycle (IGCC) power systems. The DSRP reacts the regeneration offgas with a small slipstream of coal gas to effect the desired reduction. In this project the DSRP was demonstrated with actual coal gas (as opposed to the simulated laboratory mixtures used in previous studies) in a 75-mm, 1-L size fixed-bed reactor. Integrated with this testing, a US Department of Energy/Research Triangle Institute (DOE/RTI) patented zinc titanate-based fluidizable sorbent formulation was tested in a 75-mm (3-in.) diameter fluidized-bed reactor, and the regeneration offgas from that test was treated with the bench-unit DSRP. The testing was conducted at the DOE Federal Energy Technology Center (FETC)-Morgantown in conjunction with test campaigns of the pilot-scale gasifier there. The test apparatus was housed in a mobile laboratory built in a specially equipped office trailer that facilitated moving the equipment from RTI in North Carolina to the West Virginia test site. A long duration test of the DSRP using actual coal gas and simulated regeneration offgas showed no degradation in efficiency of conversion to elemental sulfur after 160 h of catalyst exposure. An additional exposure (200 h) of that same catalyst charge at the General Electric pilot gasifier showed only a small decline in performance. That problem is believed to have been caused by tar and soot deposits on the catalyst, which were caused by the high tar content of the atypical fixed-bed gasifier gas. A six-fold larger, single-stage skid-mounted DSRP apparatus was fabricated for additional, larger-scale slipstream testing