Tanks-in-series model for high-temperature electrochemical hydrogen pump

Author(s):  
V.A. Danilov ◽  
G. Kolb ◽  
C. Cremers
2021 ◽  
Author(s):  
Gokul Venugopalan ◽  
Deepra Bhattacharya ◽  
Subarna Kole ◽  
Cameron Ysidron ◽  
Polyxeni P. Angelopoulou ◽  
...  

Ionomer electrode binders are important materials for polymer electrolyte membrane (PEM) fuel cells and electrolyzers and have a profound impact on cell performance. Herein, we report the effect of two...


2013 ◽  
Vol 50 (2) ◽  
pp. 2153-2162 ◽  
Author(s):  
T. J. Petek ◽  
J. S. Wainright ◽  
R. F. Savinell

Paliva ◽  
2021 ◽  
pp. 131-140
Author(s):  
Marek Staf ◽  
Michal Pohořelý ◽  
Siarhei Skoblia ◽  
Zdeněk Beňo ◽  
Vít Šrámek

As part of a project dealing with the material use of waste plastics processed by pyrolysis, a method for the purification of primary pyrolysis gas at temperatures above the dew point of condensing components was proposed. In order to avoid the loss of liquid products, two procedures have been proposed to study this issue. The first procedure consists in separating the pyrolysis condensate from permanent gases and its subsequent evaporation and introduction into a high-temperature reactor where the purification takes place. The second procedure used the same equipment, but the pyrolyser was connected in series with a high temperature reactor by a heated tube. The function of the device is demonstrated on a pair of pure polymers, namely highdensity polyethylene and polypropylene. In practice, however, the device is used for testing waste plastics. The mass balance of liquid, gaseous and solid products of pyrolysis and subsequent vapour phase conduction through a high-tem-perature reactor was supplemented by data from chromatographic analysis. Experiments have shown that the separation of pyrolysis and subsequent evaporation of the condensate in an independent reactor causes the formation of an undesirable amount of fine aerosol (mist). Pyrolysis without any subsequent high-temperature step produced 85–90 % condensate. The inclusion of a separate high-temperature reactor reduced the yield of condensate to 44.5–47.5 %, at the expense of the above-mentioned mist. Its conver-sion back to liquid is difficult and makes the process inefficient for industry. In tests with the series-connected pyrolyser and the high-temperature reactor, the situation was significantly better. 68.5–73.5 % of condensate was obtained in this case. In addition to the formation of mist, the conduction of steam of condensing components through the high-temperature reactor also caused a slight change in the composition of the liquids obtained. There was a decrease in the proportion of C21–C29 hydrocarbons in products and, conversely, an increase in the concentration of C5–C15 hydrocarbons. Besides verifying a suitable approach to the high-temperature processing of pyrolysis products, the experiments showed that changing a single subparameter (in this case the separation of the two reactors) significantly altered the results of the experiments. During laboratory simulation of industrial processes, it is important not to approach simplifications, but to copy all conditions as much as possible.


2019 ◽  
Vol 8 (1) ◽  
pp. 161-169 ◽  
Author(s):  
Henrik Lensch ◽  
Manuel Bastuck ◽  
Tobias Baur ◽  
Andreas Schütze ◽  
Tilman Sauerwald

Abstract. We present an equivalent circuit model for a titanium dioxide-based humidity sensor which enables discrimination of three separate contributions to the sensor impedance. The first contribution, the electronic conductance, consists of a temperature-dependent ohmic resistance. The second contribution arises from the ionic pathway, which forms depending on the relative humidity on the sensor surface. It is modeled by a constant-phase element (CPE) in parallel with an ohmic resistance. The third contribution is the capacitance of the double layer which forms at the blocking electrodes and is modeled by a second CPE in series to the first CPE. This model was fitted to experimental data between 1 mHz and 1 MHz recorded at different sensor temperatures (between room temperature and 320 ∘C) and different humidity levels. The electronic conductance becomes negligible at low sensor temperatures, whereas the double-layer capacitance becomes negligible at high sensor temperatures in the investigated frequency range. Both the contribution from the ionic pathway and from the double-layer capacitance strongly depend on the relative humidity and are, therefore, suitable sensor signals. The findings define the parameters for the development of a dedicated Fourier-based impedance spectroscope with much faster acquisition times, paving a way for impedance-based high-temperature humidity sensor systems.


Author(s):  
Elaheh Alidoosti ◽  
Jian Ma ◽  
Yingtao Jiang ◽  
Taleb Moazzeni

In the environments of high temperature (>300 °C – 1000 °C), corrosive and even irradiation application, the challenges of providing reliable and accurate flow rate measurement is significant. In comparing with many other existing technologies for normal operation environments, correlated thermal transit-time flow meter show its advantages of resolving the challenges encountered in those harsh conditions. The correlated thermal signals can be detected by two separated thermal sensors (for example, thermocouples) in series alignment along the pipe, and derive the flow rate. It was evaluated to have accurate measurement for small pipe at slow fluid speed. In the higher flow rate and big pipe size application, this technology shows its weakness due to the limitations associated with slow response time of thermal sensor, dimension, and low strength of thermal signal. In this paper, we present a sophisticated layout of thermal transit-time flow meter with numerical simulation and experiments. By numerical results, we observed that the obtained flow in the bypass route is linearly proportional to the main flow over higher range of flows showing that the measured flow is successfully extended to high range and with stable and accurate measurement results.


1948 ◽  
Vol 26a (3) ◽  
pp. 145-148 ◽  
Author(s):  
Bruce C. Lutz ◽  
John H. Wood

This is an electronic circuit useful in the control of electric air-bath furnaces having a long time lag. The control is accomplished by means of a relay that shunts a portion of the resistance in series with the furnace winding. The thermometric device is a thermocouple connected in series with a mirror-type galvanometer and a variable voltage supplied by a potentiometer. The setting of the potentiometer selects the temperature at which the device will control. A light beam falling on the mirror is reflected to one of two photocells. One photocell closes the shunt by means of the described circuit and increases the current in the furnace. This condition is maintained until the beam moves across the second photocell, when the shunt is again opened. The device will control temperatures over 1000 °C. within a precision of ± 2 °C. over any desired length of time.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7689
Author(s):  
Gad Koren ◽  
Anna Eyal ◽  
Leonid Iomin ◽  
Yuval Nitzav

Nickelate films have recently attracted broad attention due to the observation of superconductivity in the infinite layer phase of Nd0.8Sr0.2NiO2 (obtained by reducing Sr doped NdNiO3 films) and their similarity to the cuprates high temperature superconductors. Here, we report on the observation of a new type of transport in oxygen poor Nd0.8Sr0.2NiO3−δ films. At high temperatures, variable range hopping is observed while at low temperatures a novel tunneling behavior is found where a Josephson-like tunneling junction characteristic with serial resistance is revealed. We attribute this phenomenon to coupling between superconductive (S) surfaces of the grains in our Oxygen poor films via the insulating (I) grain boundaries, which yields SIS junctions in series with the normal (N) resistance of the grains themselves. The similarity of the observed conductance spectra to the tunneling junction characteristic with Josephson-like current is striking, and seems to support the existence of superconductivity in our samples.


2021 ◽  
Vol 9 ◽  
Author(s):  
Michael Wild ◽  
Lorenz Lüönd ◽  
Aldo Steinfeld

We report on the design of a modular, high-temperature thermochemical energy storage system based on endothermic-exothermic reversible gas-solid reactions for application in concentrated solar power and industrial thermal processes. It consists of an array of tubular reactors, each containing an annular packed bed subjected to radial flow, and integrated in series with a thermocline-based sensible thermal energy storage. The calcination-carbonation of limestone, CaCO3 ↔ CaO + CO2, is selected as the reversible thermochemical reaction for the experimental demonstration. Synthetized 4.2 mm-mean size agglomerates and 2 mm-mean size granules of CaO with 42 %wt sintering-inhibitor MgO support attained reaction extents of up to 84.0% for agglomerates and 31.9% for granules, and good cycling stability in pressure-swing and temperature-swing thermogravimetric runs. A lab-scale reactor prototype is fabricated and tested with both formulations for 80 consecutive carbonation-calcination cycles at ambient pressure using a temperature-swing mode between 830°C and 930°C. The reactor exhibited stable cyclic operation and low pressure drop, and yielded specific gravimetric and volumetric heat storage capacities of 866 kJ/kg and 322 MJ/m3 for agglomerates, respectively, and 450 kJ/kg and 134 MJ/m3 for granules, respectively.


2012 ◽  
Vol 727-728 ◽  
pp. 669-674 ◽  
Author(s):  
Rubens Chiba ◽  
Reinaldo Azevedo Vargas ◽  
Marco Andreoli ◽  
Emília Satoshi Miyamaru Seo

The high temperature solid oxide fuel cell (HTSOFC) can be manufactured in different configurations, which can to detach the planar and tubular. The HTSOFC are composed for four components that are cathode, electrolyte and anode for the formation of the unity cell; and interconnector, that establish connection these unity cells in series and parallel for bigger power generation. Different forming techniques are used for the manufacture of the components that need variable thicknesses for the forming ceramic films in the order of micrometers. In this work, the cathodic ceramic film of strontium-doped lanthanum manganite had been deposited on the electrolyte substrate of yttria-stabilized zirconia using the airbrush. In the forming ceramic film, the powder had been characterized by laser beam scattering granulometry and the suspension characterized by rheometry. The substrate and the ceramic film had been characterized by X-ray diffractometry and scanning electron microscopy. The conclusions of this work show that the airbrush allows flexibility in getting ceramic films with varied thicknesses with good adherence and low manufacture cost.


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