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Increasing Sr and Ti concentrations in perovskite-type $$ {\left( {{\hbox{L}}{{\hbox{a}}_{0.{75} - x}}{\hbox{S}}{{\hbox{r}}_{0.{25} + x}}} \right)_{0.{95}}}{\hbox{M}}{{\hbox{n}}_{0.{5}}}{\hbox{C}}{{\hbox{r}}_{0.{5} - x}}{\hbox{T}}{{\hbox{i}}_x}{{\hbox{O}}_{{3} - }}_\delta \left( {x = 0 - 0.{5}} \right) $$ results in slightly higher thermal and chemical expansion, whereas the total conductivity activation energy tends to decrease. The average thermal expansion coefficients determined by controlled-atmosphere dilatometry vary in the range (10.8-14.5) × 10 K at 373-1,373 K, being almost independent of the oxygen partial pressure. Variations of the conductivity and Seebeck coefficient, studied in the oxygen pressure range 10-0.5 atm, suggest that the electronic transport under oxidizing and moderately reducing conditions is dominated by p-type charge carriers and occurs via a small-polaron mechanism. Contrary to the hole concentration changes, the hole mobility decreases with increasing x. The oxygen permeation fluxes through dense ceramic membranes are quite similar for all compositions due to very low level of oxygen nonstoichiometry and are strongly affected by the grain-boundary diffusion and surface exchange kinetics. The porous electrodes applied onto lanthanum gallate-based solid electrolyte exhibit a considerably better electrochemical performance compared to the apatite-type LaSiAlO electrolyte at atmospheric oxygen pressure, while Sr and Ti additions have no essential influence on the polarization resistance. In H-containing gases where the electronic transport in $$ {\left( {{\hbox{L}}{{\hbox{a}}_{0.{75} - x}}{\hbox{S}}{{\hbox{r}}_{0.{25} + x}}} \right)_{0.{95}}}{\hbox{M}}{{\hbox{n}}_{0.{5}}}{\hbox{C}}{{\hbox{r}}_{0.{5} - x}}{\hbox{T}}{{\hbox{i}}_x}{{\hbox{O}}_{{3} - }}_\delta $$ perovskites becomes low, co-doping deteriorates the anode performance, which can be however improved by infiltrating Ni and $$ {\hbox{Ce}}{{\hbox{O}}_{{\rm{2}} - }}_\delta $$v into the porous oxide electrode matrix. [ABSTRACT FROM AUTHOR]

gas turbine power plant for CO capture, based on oxygen-permeable membranes with mixed ionic-electronic conductivity, was analysed with respect to long-term stability by means of numerical simulation. Due to the attractive transport and physicochemical properties of mixed-conducting LaNiO, this nickelate was selected as a prototype membrane material for this application. Experiments showed very slow degradation of LaNiO membranes at oxygen chemical potentials close to atmospheric conditions, which are associated with kinetic demixing and other microstructure-related factors. Interaction with CO in the intermediate temperature range also leads to lower oxygen permeation, whilst increasing oxygen pressure may cause partial phase decomposition and microstructural changes, thus again limiting the range of possible operation conditions. The relevant operational constraints were included in a detailed membrane-based gas turbine power plant model. The membrane performance degradation with time was approximated by a linear function with average rate of 3.3% per 1,000 operation hours. Furthermore, performance deterioration of the gas turbine compressor and turbine were also considered. Simulations revealed that the power plant is substantially affected by degradation of the ceramic membranes and turbomachinery components. The already rather small operating window was further narrowed when compared with a conventional gas turbine power plant. Two different designs of the membrane-based power plant were analysed: (1) with and (2) without additional combustors (afterburners) between the membrane reactor and the gas turbine. Afterburners increase thermal efficiency as well as power output, but also lead to non-negligible CO emissions. In order to have a frame of comparison, results for a conventional gas turbine power plant with degradation of turbomachinery components are also presented. Simulations representing changes in ambient temperature and fuel composition as well as failure incidents were executed to analyse the susceptibility of the gas turbine power plant to external and internal changes. [ABSTRACT FROM AUTHOR]