Simultaneous High-Temperature Removal of Alkali and Particulates in a Pressurized Gasification System. Exploratory Research on Advanced Gasification Processes for Coal, Char or Carbonaceous Residues. Annual Technical Progress Repo

摘要

In the present study, Westinghouse is examining the feasibility of a hot gas cleaning process to minimize the concentration of alkali in a high-temperature fuel gas with simultaneous particulate removal through the use of aluminosilicate materials (getters). There are four program objectives. The gettering capacity will be kinetically defined by thermogravimetric analysis of three selected getters - kaolinite, ash from a low-temperature coal char, and ash from a high-temperature gasifier. Using detailed chemical and physical analyses of the reacted aluminosilicates, the gettering mechanism will be delineated as either a chemical or a sorption process. System performance projections, for a coupled alkali and particulate removal system, will be developed from the fundamental kinetic and thermodynamic data. Finally, the system performance projections will be utilized to define a plan for concept scale-up: preliminary bench scale, ten-atmosphere exposures of the 1/8'' x 1/8'' cylindrically fabricated kaolin, low carbon ash and char samples in a 0.5 scfm stream of argon containing approx. 80 ppM NaCl have been completed. The candidate getters were exposed at bed temperatures of 850 exp 0 C and 900 exp 0 C for a one-hour period. Available results for kaolin showed that a 7.8-fold increase in total sodium content was obtained at 850 exp 0 C. At 900 exp 0 C, the gettering capacity diminished to approximately a 4.7-fold increase. Similar results are presently not available for the remaining two candidate getters. (ERA citation 05:025133)