The application of exergy analysis in the evaluation of the ethanol steam reforming (ESR) process in a catalytic membrane reactor (CMR) was presented. ESR experiments were performed at T =873-923K and P =4-12bar in a CMR containing Pd-Ag membranes sandwiched by Pd-Rh/CeO2 catalyst, aiming to produce fuel cell grade pure hydrogen. The effect of the operating conditions on the pure hydrogen production rate, hydrogen yield and recovery, exergy efficiency, and thermodynamic losses was investigated. Total hydrogen yield of 3.5mol H2 permeated per mol ethanol in feed with maximum hydrogen recuperation of 90% was measured at 923K and 12bar. The highest amount of exergy was destructed via heat losses and the retentate gas stream. Exergy efficiency up to around 50% was reached in the case of the insulated reactor at 12bar and 923K. Exergy efficiency placed between 70-90% in the case of recovery of the retentate gas in an insulated reactor. It was concluded that operating at the highest pressure, the lowest S/C ratio, and 923K gives the best exergy efficiency.Postprint (author's final draft

An exergy analysis of the ethanol steam reforming process using a Pd-Rh catalyst supported on ceria in a Pd-Ag membrane reactor has been performed based on experimental data. Both chemical and physical exergy for chemical species together with thermodynamic loss calculations have been considered to evaluate the exergy efficiency of the process. The system has been studied under different operational conditions in terms of temperature (873-923 K), pressure (4-12 bar), and feed flow rate using a water-ethanol mixture of 50-50% volume (S/C = 1.6). A significant exergy efficiency dependency on the fuel flow rate and pressure has been encountered when considering the heat loss from the reactor. The best results regarding the exergetic and thermal efficiency have been obtained at high flow rates and 8-12 bar, which has been attributed to the higher hydrogen permeation through the membrane. The chemical reactions involved in the reforming process and the heat losses are the main sources of exergy destruction.Postprint (published version

In chemical-looping combustion, the oxygen needed for combustion of fuel is provided by metal oxides called oxygen carriers, and inherent separation of CO2 is achieved without energy penalty. For gaseous fuels, such as natural gas, Ni-based oxygen carriers have generally been shown to be the most reactive. But as Ni-based materials are burdened by high costs and environmental risks with respect to toxicity, it is of high importance to find viable non-Ni alternatives. In the EU-financed project INNOCUOUS, one of the key issues is to find novel non-Ni based oxygen carriers. In this paper results from reactivity investigations of three groups of oxygen carrier materials are reported. The materials were prepared by spray-drying, and are based on 1) CuO, 2) Ca-Mn-X-O where X=Cu, Fe, Ti and Mg, and 3) Mg-Mn-O. A number of materials showed a combination of sufficient mechanical strength, high release of gas phase oxygen and high reactivity with methane, and can thus be considered viable alternatives to Ni-based materials