Tin as a Possible Candidate for Solar Thermochemical Redox Process for Hydrogen Production

The feasibility to produce hydrogen in the Sn–H2O/SnO2–C thermochemical water splitting redox process depends mainly on the efficiency of the tin hydrolysis step, which has not been studied adequately so far, while the cassererite carboreduction is implemented by industry for tin production. The present work deals with the hydrolysis of different kinds of tin powders at different experimental conditions at moderate temperature range 180–620°C. In spite of the fact that the rate of hydrogen production is lower compared with other metals, e.g., zinc, at the same reactor temperature, high conversion level was obtained in a controllable reaction. Consequently, tin can be a relevant candidate for solar hydrogen production considering the advantage of significant lower temperatures required for the solar carboreduction of its oxide.

Selectivity changes of acetone transformation over ZSM-5 zeolites with different acido-basic properties

Acetone transformation catalyzed by HZSM-5 and NaZSM-5 zeolites and by zeolites modified with basic oxides was studied in an integral reactor at a temperature of 350 °C. Modification of acido-basic properties of ZSM-5 zeolites resulted both in the total conversion changes and in the essential changes in the product composition. Isobutene was found to be the main product over HZSM-5 zeolites exhibiting low activity, while aromatics prevailed when high conversion level was attained. Classical condensation of acetone yielding mesityloxide and phorones was observed over NaZSM-5 zeolites impregnated with CaO and ZnO.