Volume hydrogen

Here Q is the charge delivered by the anode, V(H2) is the measured hydrogen volume and V(H2) its molecular volume under the same test conditions. 

Within the series of the Chemical Economics Handbook published by SRI Consulting, nearly all known direct hydrogen producers worldwide are cited (see www.sriconsulting.com). Another possibility to estimate the produced hydrogen volumes is from the respective hydrogen demand of the final products (e.g., from ammonia, methanol or refinery products) (see LBST (1998)). 

Fig. 13 Mean bubble sizes and specific surface areas of the dispersed gas phase in the biphasic system H2/H2O as a function of the hydrogen volume rate...

A hydrogen-volume-measurement burette A hydrogen cylinder... 

For example, mixtures of hydrogen and air burn in mixture ratios of 0.04 to 0.74 by hydrogen volume. The lower limit is 0.04 and the upper limit is 0.74 by volume. 

Hydrogen volume flow rate (mole fraction) 24 Nl/h (97%) Oxygen volume flow rate (mole fraction) 12 Nl/h (20%)... 

The constant container volume V consists of the variable shares for the liquid V and gaseous hydrogen volume V", in which the following applies ... 

These measurements are really important for electrochemical engineering. The smaller the voltage is, the cheaper the hydrogen production. The hydrogen volume flow rate is directly related to the current according with the Faraday law ... 

Electrochemical cell with quartz window and saturated calomel electrode as a reference electrode was used (Fig. 3). Photoelectrochemical measurements were conducted with Pl-50-1 potentiostat under illumination power density of 75 mW/cm. At first the efficiency of energy accumulation (in the form of absorbed hydrogen) was estimated from the cathode discharge curves and from the hydrogen volume released under cathode heating. The volume of hydrogen released was measured in the tailor-made setup. The discharge capacity measurements were performed in electrochemical cell with nickel counter electrode. 

The degree of Co reduction has been determined by a chemical method based on measurements of hydrogen volume extracted from the reduced catalyst at its acid treatment by using a closed system with a gas circulating unit. The degree of cobalt ion reduction has been ealeulated as a pereent ratio of number of cobalt atoms in zero-valence state to total number of cobalt atoms in catalyst. 

Only a small one-digit percentage of the overall hydrogen volume is produced by electrolysis of water today. This process is typically interesting if power is very cheap, or natural gas is not available and only a small H2 quantities are required. 

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