NOVEL TECHNOLOGIES FOR GASEOUS CONTAMINANTS CONTROL

Turk, B. S. ; Gupta, R. P. ; Gangwal, S. ; Toy, L. G. ; Albritton, J. R. ; Henningsen, G. ; Presler-Jur, P. ; Trembly, J.

Research Triangle Institute

关键词: Desulfurization;    Capitalized Cost;    Impurities;    Thermal Efficiency;    Testing;   

RP-ID  :  None
RP-ID  :  AC26-99FT40675
RP-ID  :  1027121

美国|英语

来源: UNT Digital Library

【 摘 要 】

Overall objective of this project was to develop a technology platform for cleaning/conditioning the syngas from an integrated gasification combined cycle (IGCC) system at elevated temperatures (500-1,000 F) and gasifier pressures to meet the tolerance limits for contaminants, including H{sub 2}S, COS, NH{sub 3}, HCl, Hg, and As. This technology development effort involved progressive development and testing of sorbent/catalytic materials and associated processes through laboratory, bench, pilot, and demonstration testing phases, coupled with a comprehensive systems analysis at various stages of development. The development of the regenerable RTI-3 desulfurization sorbent - a highly attrition-resistant, supported ZnO-based material - was the key discovery in this project. RTI-3's high attrition resistance, coupled with its high reactivity, effectively allowed its application in a high-velocity transport reactor system. Production of the RTI-3 sorbent was successfully scaled up to an 8,000-lb batch by Sued-Chemie. In October 2005, RTI obtained U.S Patent 6,951,635 to protect the RTI-3 sorbent technology and won the 2004 R&D 100 Award for development of this material. The RTI-3 sorbent formed the basis for the development of the High-Temperature Desulfurization System (HTDS), a dual-loop transport reactor system for removing the reduced sulfur species from syngas. An 83-foot-tall, pilot HTDS unit was constructed and commissioned first at ChevronTexaco's gasification site and later at Eastman's gasification plant. At Eastman, the HTDS technology was successfully operated with coal-derived syngas for a total of 3,017 hrs over a 12-month period and consistently reduced the sulfur level to <10 ppmv. The sorbent attrition rate averaged {approx}31 lb/MM lb of circulation. To complement the HTDS technology, which extracts the sulfur from syngas as SO{sub 2}, RTI developed the Direct Sulfur Recovery Process (DSRP). The DSRP, operating at high pressure and high temperature, uses a small slipstream of syngas to catalytically reduce the SO{sub 2} produced in the warm syngas desulfurization process to elemental sulfur. To demonstrate this process at Eastman, RTI constructed and commissioned a skid-mounted pilot DSRP unit. During its 117-h operation, the DSRP system achieved 90% to 98% removal of the inlet sulfur. The DSRP catalyst proved very robust, demonstrating consistent reaction rates in multiple experiments over a 3-year period. Sorbent materials for removing trace NH{sub 3}, Hg, and As impurities from syngas at high temperature and high pressure were developed and tested with real syngas. A Li{sub 4}SiO{sub 4} sorbent for removal of CO{sub 2} from syngas at high temperature was also developed and tested. The Li{sub 4}SiO{sub 4} material demonstrates excellent CO{sub 2} removal, but its regeneration was found to be technically challenging. Additionally, reverse-selective polymer membrane materials were investigated for the bulk removal of CO{sub 2} and H{sub 2}S from syngas. These materials exhibited adequate separation at ambient conditions for these acid gases. Field testing of these membrane modules with real syngas demonstrated potential use for acid-gas separation from syngas. The HTDS/DSRP technologies are estimated to have a significant economic advantage over conventional gas cleanup technologies such as Selexol{trademark} and Rectisol. From a number of system studies, use of HTDS/DSRP is expected to give a 2-3 percentage point increase in the overall IGCC thermal efficiency and a significant reduction in capital cost. Thus, there is significant economic incentive for adaptation of these warm gas cleanup technologies due to significantly increased thermal efficiency and reduction in capital and operating costs. RTI and Eastman are currently in discussions with a number of companies to commercialize this technology.