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ProGasMix FC - Versatile gas mixer for wide range control of partial pressures

ProGasMix FC (FC as in Fuel Cell) is a unique tool for students and researchers in materials science, suitable for use with the ProboStat or other systems using variable controlled atmospheres. It offers the economy, simplicity, and insight to those that value versatility and wide ranges of mixing. Partial pressures are calculated from flowmeter readings via accompanying software.

The ProGasMix FC is a versatile rotameter-based manual gas mixer especially developed for laboratory investigations of the properties of oxides at high temperatures vs T, pO2, pH2O etc. (see methods page) or fuel cell tests with humidification of fuel and/or oxidant. The mixer includes safety features for overpressure (gas blockage).

The mixer is based on the unique "Oslo mixer" at University of Oslo. It has been used in countless studies of conductivity and other properties as a function of pO2, pH2O, etc., and is especially known for its ability to deliver two mixtures suitable for concentration cell measurements (of for instance transport numbers of oxide ions and protons independently), permeation studies and fuel cell component tests.

ProGasMix FC mixes any connected three gases into one or two mixtures. First mixture is input gas #1 diluted with input gas #2, even down to ppm ratios. A second mixture can be modified from the first for concentration cell measurements by diluting more with gas #2, or made from input gases #2 and #3 for example for fuel cell tests. Humidity of both mixtures individually can be controlled from 100% relative/~3% atm (at 25ºC) down to 0.3% relative, or the wetting can be skipped to obtain dry gas mixtures. For higher water contents the made mixture can be humidified externally after the mixer with optional humidifier unit. The mixer also has provision to connect custom wetting stages for example for D2O.

Compared to mass-flow meter based system of equal features, the ProGasMix is order of magnitude less expensive and will last virtually forever. ProGasMix FC requires no frequent maintenance, repairs or calibration. The mixer is simple, serviceable, and "transparent" to the user, making it easy for users to understand what goes on inside the mixer.

The rotameters are slightly less accurate than mass flow controllers, but as the mixtures typically span pO2 or pH2O over several orders of magnitude (logarithmically) the few percent linear error of rota-meters become negligible.

Allows

  • Fuel cell tests

  • Conductivity measurements, impedance spectroscopy, etc. vs. pO2 , pH2O, pH2

  • Ionic transport number measurements by EMF of concentration cells

  • Transport numbers of oxide ions and protons independently

  • Gas permeation measurements

  • Easy to inverse dual mixture outputs for transients or elimination of offsets

Specifications

  • Safe mix and supply of gases for tests of small fuel cells
  • Wide range mixing of three input gases into two output mixtures (down to ppm levels)
  • pH2O can be set for both output mixtures individually, range 0.005% to ~3% atm. Up to 100% with external, optional humidifier
  • Two outputs for two mixtures, flow range for each 3 - 83 mln/min (air) near atmospheric pressures
  • Mixer- and output mixture pressures near atmospheric pressure with relief valve to protect from pressure buildup on case of cell blockage
  • Flow meter operation manual. Mixture calculation, flow meter reading conversions, mixtures and equilibria: custom software (for Windows operation system)

Physical description

  • Passive gas mixing unit with 12 precision variable area flow meters
  • Desktop size: 50 x 55 x 60 cm, 40 kg
  • Internal voltage 24V DC, power supply included
  • Material in contact with gas: Copper, Brass, Stainless steel, Buna-N, Glass. On ventilation: Natural rubber, Silicon and Plastic

For further details see methods page and read the ProGasMix manual

  • 50 x 55 x 60 cm and 40 kg
  • Illuminated bubblers

 

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These articles refer to ProboStat or other NORECS products, filtered with keywords: 'ProGasMix, Oslo mixer'  
ID=286

Functional properties of La0.99X0.01Nb0.99Al0.01O4−δ and La0.99X0.01Nb0.99Ti0.01O4−δ proton conductors where X is an alkaline earth cation

Authors Mariya E. Ivanovaa, Wilhelm A. Meulenberga, Justinas Palisaitisb, Doris Sebolda, Cecilia Solísd, Mirko Ziegnere, Jose M. Serrad, Joachim Mayerb, Michael Hänsele, Olivier Guillona
Source
Journal of the European Ceramic Society
Time of Publication: 2014-12
Abstract Lanthanum niobates with general formulas of La0.99X0.01Nb0.99Al0.01O4−δ and La0.99X0.01Nb0.99Ti0.01O4−δ (X = Mg, Ca, Sr or Ba) were synthesized via the conventional solid state reaction. Specimens with relative density above 96% were produced after sintering. Structural and phase composition studies revealed predominant monoclinic Fergusonite structure for the majority of samples. SEM and TEM studies elucidated the effect of the used dopant combinations on grain growth, micro-crack formation and secondary phase formation. Results from microstructural study were correlated to the grain interior and grain boundary conductivities for selected samples (La0.99Sr0.01Nb0.99Al0.01O4−δ and La0.99Sr0.01Nb0.99Ti0.01O4−δ). The majority of co-doped niobates exhibited appreciable protonic conductivity under humid atmospheres at intermediate temperatures. Sr- or Ca-doped compounds displayed the highest total conductivities with values for LSNA equal to 6 × 10−4 S/cm and 3 × 10−4 S/cm in wet air and in wet 4% H2–Ar (900 °C), respectively. Additionally, thermal expansion was studied to complete functional characterization of co-doped LaNbO4.
Keywords Proton-conducting ceramic materials, Hydrogen transport ceramic membranes, Rare earth ortho-niobates, Acceptor-doped lanthanum niobates, ProGasMix
Remark Link
ID=214

Synthesis and Characterization of Nonsubstituted and Substituted Proton-Conducting La6–xWO12–y

Authors Janka Seeger, Mariya E. Ivanova, Wilhelm A. Meulenberg, Doris Sebold, Detlev Stöver, Tobias Scherb, Gerhard Schumacher, Sonia Escolástico, Cecilia Solís, and José M. Serra
Source
Inorganic Chemistry
Publisher: ACS Publications, Time of Publication: 2013
Abstract Mixed proton–electron conductors (MPEC) can be used as gas separation membranes to extract hydrogen from a gas stream, for example, in a power plant. From the different MPEC, the ceramic material lanthanum tungstate presents an important mixed protonic–electronic conductivity. Lanthanum tungstate La6–xWO12–y (with y = 1.5x + δ and x = 0.5–0.8) compounds were prepared with La/W ratios between 4.8 and 6.0 and sintered at temperatures between 1300 and 1500 °C in order to study the dependence of the single-phase formation region on the La/W ratio and temperature. Furthermore, compounds substituted in the La or W position were prepared. Ce, Nd, Tb, and Y were used for partial substitution at the La site, while Ir, Re, and Mo were applied for W substitution. All substituents were applied in different concentrations. The electrical conductivity of nonsubstituted La6–xWO12–y and for all substituted La6–xWO12–y compounds was measured in the temperature range of 400–900 °C in wet (2.5% H2O) and dry mixtures of 4% H2 in Ar. The greatest improvement in the electrical characteristics was found in the case of 20 mol % substitution with both Re and Mo. After treatment in 100% H2 at 800 °C, the compounds remained unchanged as confirmed with XRD, Raman, and SEM.
Keywords ProGasMix
Remark lanthanum tungstate
La6–xWO12–y
Link
norecs.com

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