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Highlights • CaO/CuO/NiO sorption-enhanced steam methane reforming is studied. • High hydrogen yield (2.8 mol H2 /mol CH4) and reforming efficiency (84%) are assessed. • Integration with a SOFC fuel cell is proposed as practical cogeneration application. • Levelised costs of electricity and heat are 0.096 € kW h−1 and 0.19 € kW h−1. • CO 2 emissions can be avoided at no cost. Abstract In this article, a process for sorption-enhanced steam methane reforming in an adiabatic fixed-bed reactor coupled with a solid oxide fuel cell (SOFC) is evaluated using a 1D numerical reactor model combined with a simplified fuel cell simulation. A novel material comprising CaO/CuO/Al 2 O 3 (NiO) pellets is considered. Three operating stages are considered in the proposed system, namely (i) CaO carbonation/reforming, (ii) Cu and Ni oxidation, and (iii) CaCO 3 calcination/CuO and NiO reduction. The operating conditions that enable cyclic operation of these stages and the strategy needed to switch between each stage are evaluated. Under the adopted control strategy, methane conversion was about 95%, whilst H 2 yield and purity were around 3.2 mol H2 mol CH4 −1 and 90%, respectively. Moreover, a concentrated CO 2 stream ready for storage was obtained. By using a portion of the produced H 2 to make the process self-sufficient from an energy standpoint, an equivalent H 2 yield and a reforming efficiency of about 2.8 mol H2 mol CH4 −1 and 84% were achieved, respectively. With respect to SOFC integration, net power and thermal energy generation of around 11 kW and 6 kW, respectively, can be achieved. With respect to the chemical energy of the inlet methane, the net electrical and thermal efficiencies of the considered process are 56% and 30%, respectively, i.e. , the overall efficiency of the entire system is 86%. The proposed cogeneration system showed better thermodynamic, environmental and economic performances than those of conventional systems, with an investment pay-back period of 2.2 years in the worst-case scenario. The levelised cost of electricity, of heat and total power were about 0.096 € kW h−1, 0.19 € kW h−1, and 0.065 € kW h−1, respectively, while the CO 2 emissions were avoided at no cost. [ABSTRACT FROM AUTHOR]

Although exploitation of Dual Fluidized Bed systems (DFB) is currently being explored in various fields, DFBs present some criticalities, mainly related to effective control of solids recirculation and to avoidance of gas leakage between the beds, extremely critical in Chemical Looping Reforming (CLR) for hydrogen production. For the latter, the choice of the degree of oxygen carrier oxidation/reduction, operation temperature and loop design makes the design even more challenging. This paper aims at the quantitative assessment of the influence of design variables by means of the numerical simulation of a DFB-CLR process operated at steady state conditions. The model couples a simple hydrodynamic simulation of a DFB system equipped with non-mechanical valves for bed solids circulation with a 1D, dynamic and non-isothermal CLR model developed to determine temperature and oxidation degree of solids and gaseous species concentration at the exit of both Air and Fuel Reactors. The DFB, consisting of a riser and of a bubbling fluidized bed (BFB) as Air and Fuel Reactors respectively, was modeled as a combination of interconnected blocks (riser, cyclone, L-valve, BFB, loop-seal) after selection of constitutive equations. Methane and Nickel (II) oxide were selected as fuel and oxygen carrier. Results corresponding to steady state operation are presented and the effects of operating conditions on the expected process performance are assessed. It is concluded that an appropriate choice of both operating temperature and amount of oxygen transported by oxygen carrier from AR to FR is an essential prerequisite in order to ensure process feasibility and good performances in terms of CH 4 conversion and H 2 selectivity. [ABSTRACT FROM AUTHOR]

This paper presents a novel quasi -autothermal hydrogen production process. The proposed layout couples a Chemical Looping Combustion (CLC) section and a Steam Methane Reforming (SMR) one. In CLC section, four packed-beds are operated using Ni as oxygen carrier and CH 4 as fuel to continuously produce a hot gaseous mixture of H 2 O and CO 2 . In SMR section, two fixed-beds filled with Ni-based catalyst convert CH 4 and H 2 O into a H 2 -rich syngas. Four heat exchangers were employed to recover residual heat content of all the exhaust gas currents. By means of a previously developed 1D numerical model, a dynamic simulation study was carried out to evaluate feasibility of the proposed system in terms of methane conversion (100% circa), hydrogen yield (about 0.65 mol H2 /mol CH4 ) and selectivity (about 70%), and syngas ratio (about 2.3 mol H2 /mol CO ). Energetic and environmental analyses of the system performed with respect to conventional steam methane reforming, highlights an energy saving of about 98% and avoided CO 2 emission of about 99%. [ABSTRACT FROM AUTHOR]

A mathematical model has been developed to predict fragmentation of particles under a wide range of pyrolysis and combustion conditions. The model is an upgrade of a previous one that took into account only fragmentation during the heat up and devolatilization stage. The model calculates the temperature and oxygen profiles within the particle, the evolution of internal porosity as a consequence of both devolatilization and carbon combustion, the mechanical stress caused by temperature gradients, and by volatiles-generated overpressure inside the particles. Eventually the model calculates the probability of rupture of the particle based on the Weibull (1939) theory. The model has been used to simulate heating of coal particles under inert conditions at different heating rates and temperatures showing good agreement with previous work. The model has been further used to simulate heating under oxidative conditions in order to highlight the role of combustion on fragmentation phenomena. [ABSTRACT FROM PUBLISHER]