Both chemical looping processes and oxygen permeable ceramic membranes require gas-solid surface reaction to occur in order to function; the two approaches have much in common at a fundamental level. Both approaches, through either dynamic operation in the case of looping or membrane operation, allow a degree of process intensification through simultaneous reaction and separation. Here the use of chemical looping and oxygen permeable ceramic membranes for hydrogen production is reviewed. Hydrogen production from water with various reducing gases is covered, as is synthesis gas production from hydrocarbons with various oxidants (this requiring 10 further hydrogen separation from the synthesis gas). The two approaches are compared and contrasted.
We report the preparation and validation of the first fully synthetic gaseous reference standards of CO2 and CH4 in a whole air matrix with an isotopic distribution matching that is in the ambient atmosphere. The mixtures are accurately representative of the ambient atmosphere and were prepared gravimetrically. The isotopic distribution of the CO2 was matched to the abundance in the ambient atmosphere by blending (12)C-enriched CO2 with (13)C-enriched CO2 in order to avoid measurement biases introduced by measurement instrumentation detecting only certain isotopologues. The reference standards developed here have been compared with standards developed by the National Institute of Standards and Technology and standards from the WMO scale. They demonstrate excellent comparability.
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