Thermochemistry of La2O2CO3 decomposition

Shirsat, A.N.; Ali, Manjoor; Kaimal, K.N.G.; Bharadwaj, S.R.; Das, D.

doi:10.1016/s0040-6031(02)00459-8

Cited by 92 publications

(65 citation statements)

References 9 publications

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“…At 1,223 K and atmospheric pressure, the presence of CO 2 apparently has no detrimental effect within the limits of experimental error, which is in agreement with thermodynamic data (e.g. [59,60] and references therein). However, analysis of the thermodynamic properties of lanthanum carbonate and oxycarbonate shows that an opposite situation is likely to take place at the elevated pressure range necessary for the GTPP, even if temperatures are moderately higher than 1,223 K. Note also that the data shown in suggest the feasibility of thermal cycling to prevent membrane degradation.…”

Section: Resultssupporting

confidence: 90%

Simulation of a mixed-conducting membrane-based gas turbine power plant for CO2 capture: system level analysis of operation stability and individual process unit degradation

Colombo

Хартон

Viskup

et al. 2010

J Solid State Electrochem

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A gas turbine power plant for CO 2 capture, based on oxygen-permeable membranes with mixed ionicelectronic conductivity, was analysed with respect to longterm stability by means of numerical simulation. Due to the attractive transport and physicochemical properties of mixed-conducting La 2 NiO 4+δ , this nickelate was selected as a prototype membrane material for this application. Experiments showed very slow degradation of La 2 NiO 4+δ membranes at oxygen chemical potentials close to atmospheric conditions, which are associated with kinetic demixing and other microstructure-related factors. Interaction with CO 2 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 2 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.

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Section: Resultssupporting

confidence: 90%

Simulation of a mixed-conducting membrane-based gas turbine power plant for CO2 capture: system level analysis of operation stability and individual process unit degradation

Colombo

Хартон

Viskup

et al. 2010

J Solid State Electrochem

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“…5), where signals derived from La 2 O 2 CO 3 phase are clearly visible. This is in good agreement with the literature 10, 14 , which indicates that a thermal decomposition of lanthanum carbonate is a complex process and occurs with the formation of a stable intermediate product (La 2 O 2 CO 3 ). This compound, in turn, decomposes to lanthanum oxide at higher temperatures.…”

Section: Calcination Studiessupporting

confidence: 93%

“…The eff ect of storage conditions on the composition of the cobalt-lanthanum catalyst precursor It is well know that lanthanum oxide is a highly hygroscopic compound and its easy interaction with H 2 O and atmospheric CO 2 may affect signifi cantly the phase composition of such a material (by creating hydroxides and carbonates) 10, 11, 14 . Hence, storage conditions of lanthanum oxide are an essential factor infl uencing its properties and consequently the properties of catalysts, in which La 2 O 3 is an important component.…”

Section: Calcination Studiesmentioning

confidence: 99%

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Cobalt-lanthanum catalyst precursors for ammonia synthesis: determination of calcination temperature and storage conditions

Zybert

Tarka

Mierzwa

et al. 2017

Polish Journal of Chemical Technology

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A thermal decomposition of a cobalt-lanthanum catalyst precursor containing a mixture of cobalt and lanthanum compounds obtained by co-precipitation were studied using thermal analysis coupled with mass spectrometry (TG-MS). Studies revealed that the calcination in air at 500 o C is suffi cient to transform the obtained cobalt precipitate into Co 3 O 4 , but it leads to only partial decomposition of lanthanum precipitate. In order to obtain Co/La catalyst precursor containing La 2 O 3 the calcination in air at the temperature about 800 o C is required. However, it is unfavorable from the point of view of textural properties of the catalyst precursor. A strong effect of storage conditions on the phase composition of the studied cobalt-lanthanum catalyst precursor, caused by the formation of lanthanum hydroxide and lanthanum carbonates from La 2 O 3 when contacting with air, was observed.

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“…Within the temperature range 773-1190 K, the median enthalpy and entropy of the oxy-carbonate decomposition in air atmosphere has been reported to be 145.5 ± 5.0 kJ mol -1 and 119.2 ± 5.0 J mol -1 K -1 , respectively [23]. At 923K, these values yield a p K d of 2.02, which also indicates the highly basic nature of La 2 O 2 CO 3 .…”

Section: Discussionmentioning

confidence: 93%

Lux-Flood Basicity of Mixed La2O3-Alkali Molten Carbonates Determined by Analysis of their Oxygen Solubility Properties

Frangini¹

2009

TOPCJ

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Abstract:The Lux-Flood basicity of La 2 O 3 -containing alkali molten carbonate mixtures has been quantitatively estimated by a gas solubility method based on the use of acidic gaseous O 2 for the titration of the oxide concentration in the melt. The amount of gaseous oxygen dissolved in the melt in form of peroxide ion has been taken as a quantitative probe for the carbonate basicity. Results demonstrate that addition of a 0.5 mol % of La 2 O 3 to alkali carbonates is able to dramatically increase the melt basicity and that the degree of this basicity change mostly depends on the melt composition in terms of the average cation size of the alkali carbonate mixture. Plausible dissolution paths of La 2 O 3 in molten carbonates under both acidic and basic regimes are also discussed.

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Thermochemistry of La2O2CO3 decomposition

Cited by 92 publications

References 9 publications

Simulation of a mixed-conducting membrane-based gas turbine power plant for CO2 capture: system level analysis of operation stability and individual process unit degradation

Simulation of a mixed-conducting membrane-based gas turbine power plant for CO2 capture: system level analysis of operation stability and individual process unit degradation

Cobalt-lanthanum catalyst precursors for ammonia synthesis: determination of calcination temperature and storage conditions

Lux-Flood Basicity of Mixed La2O3-Alkali Molten Carbonates Determined by Analysis of their Oxygen Solubility Properties

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