Dual Phase Membrane for High Temperature CO(2) Separation. (Technical Report, September 1, 2004-August 30, 2005).

[摘要] Research in the previous years in this project found that stainless steel supports are oxidized during high temperature, dual phase membrane separation of carbon dioxide (with oxygen). Consequently, a new material has been sought to alleviate the problems with oxidation. Lanthanum cobaltite oxide is a suitable candidate for the support material in the dual phase membrane due to its oxidation resistance and electronic conductivity. Porous lanthanum cobaltite membranes were prepared via the citrate method, using nitrate metal precursors as the source of La, Sr, Co and Fe. The material was prepared and ground into a powder, which was subsequently pressed into disks for sintering at 900 deg C. Conductivity measurements were evaluated using the four-probe DC method. Support pore size was determined by helium permeation. Conductivity of the lanthanum cobaltite material was found to be at a maximum of 0.1856 S/cm at 550 deg C. The helium permeance of the lanthanum cobaltite membranes for this research was on the order of 10(sup -6) moles/m(sup 2)(dot)Pa(dot)s, proving that the membranes are porous after sintering at 900 deg C. The average pore size based on steady state helium permeance measurements was found to be between 0.37 and 0.57(micro)m. The lanthanum cobaltite membranes have shown to have desired porosity, pore size and electric conductivity as the support for the dual-phase membranes. Molten carbonate was infiltrated to the pores of lanthanum cobaltite membranes support. After infiltration with molten carbonate, the helium permeance of the membranes decreased by three orders of magnitude to 10(sup -9) moles/m(sup 2)mPa-s. This number, however, is one order of magnitude larger than the room temperate permeance of the stainless steel supports after infiltration with molten carbonate. Optimization of the dip coating process with molten carbonate will be evaluated to determine if lower permeance values can be obtained with the lanthanum cobaltite membrane supports.

[发布机构] Technical Information Center Oak Ridge Tennessee

[学科分类] 工程和技术（综合）

[关键词] Carbon dioxide;Membranes;High temperature;Separation processes;Progress report