Hydrogen flux measurement

Both cold and hot inert gas pressure tests were performed on samples of brazed cermet membranes in advance of hydrogen flux measurements in order to ascertain the integrity of the Inconel 600-to-cermet seal under high temperature and pressure conditions. The procedure used in these tests has been described elsewhere [Rothenberger etal., 1999]. 

Hydrogen Flux Measurement in High Pressure Permeation Unit... 

Fig. 7.4 Hydrogen fluxes measured from the high pressure permeation unit for the unsupported BCN membrane...

The use of spot hydrogen flux measurements in assessing corrosion and crack risk in refinery applications... 

Table 3.2 Manual calculation of hydrogen activity at inside of pipe from hydrogen flux measurement. To convert flux Into an activity of hydrogen at the inside face of a vessel or pipe wall, the following are required ... 

The cells shown in Figs. 28 and 29 all operate according to the same principles, which have been developed by Arup. The interior of the cell acts as the anode chamber, and a metal oxide cathode placed inside the cell in an alkaline electrolyte acts as the counter electrode. The hydrogen flux across the integrated membrane (coated with palladium on the internal surface) can be measured as the potential drop across a resistor placed between the membrane and the counter electrode. 

We have developed the measure of molecular hydrogen flux in vacuum, for calibration of mass-spectrometer. 

The mean value of the hydrogen flux is 7.7-1 O 7 m3Pa/s, and the relative value of standard deviation of the accidental component of error of measurements is 1%. The relative value of allowed deviation at the confidence 90% is 1.7%. 

Keramati and Zemel, 1982) for both hydrogen fluxes and concentration measurements. At this point it must be recalled that other semiconductors in their thin-film form (e.g., ZnO, CdS, Sn02-doped Sb) have also been tested for sensing gases, but their selectivity has not yet proved to be adequate. 

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