Thermochemical water-splitting cycles are an environmentally friendly approach to hydrogen production: all chemicals in the process are recycled, the only required input is water and concentrated solar radiation can provide the heat necessary for the reactions. The sodium-manganese-ferrite cycle is very appealing given the moderate operating temperatures (750-800°C) [1,2]. The hydrogen production and oxygen releasing steps are schematically represented by reactions (1) and (2) [1, 2]: 2MnFe2O4(s)+3Na2CO3(s)+H2O(g)=6Na(Mn1/3Fe2/3)O2(s)+3CO2(g)+H2(g) (1) 6Na(Mn1/3Fe2/3)O2(s)+3CO2(g)= 2MnFe2O4(s)+3Na2CO3(s)+1/2O2(g) (2) In order to demonstrate the on-sun feasibility of the cycle, a reactor-receiver was installed in a 1.5kW solar facility, which includes a heliostat and a parabolic reflector. The cavity receiver traps focused radiation and energy is delivered to the reactants by conduction through the cavity walls. An experimental campaign was carried out to evaluate the performance of the reactor. The inner temperature distribution and hydrogen production were measured and mapped as a function of water flowrate, argon flowrate, and solar radiation. A Finite Element Model (FEM) was developed to describe the transport of energy, mass and momentum within the reactor. The results obtained were compared to experimental measurements, showing good agreement between calculated and experimental data. The implemented model allows an analysis of the system’s behavior and will be used to optimize reactor design.
On site validation of the thermochemical hydrogen production through mixed ferrite cycle / Murmura, MARIA ANNA; R., Grena; M., Lanchi; F., Padella; F., Varsano; B., Brunetti; Annesini, Maria Cristina; T., De Sclavis; I., Fabriani; L., Turchetti. - STAMPA. - (2012). (Intervento presentato al convegno World Hydrogen Energy Conference tenutosi a Toronto, Canada nel 3-8 Giugno 2012).
On site validation of the thermochemical hydrogen production through mixed ferrite cycle
MURMURA, MARIA ANNA;ANNESINI, Maria Cristina;
2012
Abstract
Thermochemical water-splitting cycles are an environmentally friendly approach to hydrogen production: all chemicals in the process are recycled, the only required input is water and concentrated solar radiation can provide the heat necessary for the reactions. The sodium-manganese-ferrite cycle is very appealing given the moderate operating temperatures (750-800°C) [1,2]. The hydrogen production and oxygen releasing steps are schematically represented by reactions (1) and (2) [1, 2]: 2MnFe2O4(s)+3Na2CO3(s)+H2O(g)=6Na(Mn1/3Fe2/3)O2(s)+3CO2(g)+H2(g) (1) 6Na(Mn1/3Fe2/3)O2(s)+3CO2(g)= 2MnFe2O4(s)+3Na2CO3(s)+1/2O2(g) (2) In order to demonstrate the on-sun feasibility of the cycle, a reactor-receiver was installed in a 1.5kW solar facility, which includes a heliostat and a parabolic reflector. The cavity receiver traps focused radiation and energy is delivered to the reactants by conduction through the cavity walls. An experimental campaign was carried out to evaluate the performance of the reactor. The inner temperature distribution and hydrogen production were measured and mapped as a function of water flowrate, argon flowrate, and solar radiation. A Finite Element Model (FEM) was developed to describe the transport of energy, mass and momentum within the reactor. The results obtained were compared to experimental measurements, showing good agreement between calculated and experimental data. The implemented model allows an analysis of the system’s behavior and will be used to optimize reactor design.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
