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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]

Abstract: The purpose of this paper is to conduct a parametric study to show the best steam to carbon ratio that produces the maximum system performance of an integrated gasifier for hydrogen production. The study focuses on the energy and exergetic efficiency of the system and hydrogen production. The work is completed using computer simulation models in Engineering Equation Solver software package. This software is used for its extensive thermodynamic properties library. An equilibrium based model is used to determine the performance of the system. The data is presented in graphs which show the chemical composition in molar fractions of the syngas, the overall energy and exergy efficiency of the system, and the hydrogen production rates. A study of these parameters is conducted by varying the steam to carbon ratio entering the gasifier and the ambient temperature. It is observed that the higher the steam to carbon ratio that is achieved the more hydrogen and more power the plant is able to produce. Because of this, the exergy and energy efficiency of the system increases as the steam to carbon ratio increases as well. It is also observed that the system favors a lower ambient temperature for maximum exergy efficiency and hydrogen production. [Copyright &y& Elsevier]

Abstract: In many visions and roadmaps, there is a broad agreement that fuel cells – both for stationary and mobile applications – are the key technology to allow the development of a hydrogen infrastructure. Furthermore, this development is generally thought to be based on a gradual, decentralised evolution. Nevertheless, in this paper it is argued that, taking into account the entire hydrogen chain (production, transport, storage, distribution and end-use), this decentralised fuel-cell based philosophy shows some serious flaws. Therefore, a new hydrogen-transition approach was pushed forward: mixing in of hydrogen into the natural-gas bulk. Using Flanders – the Northern part of Belgium – as a case study, the development of a transitory hydrogen infrastructure has been studied, taking into account the entire hydrogen chain and its dynamics, from production to end use. In a next step, this transition is being quantified. An optimisation model has been developed using Matlab and the commercial solvers GAMS and CPLEX. Following a mixed-integer linear-programming approach, this model is able to determine the economically optimal hydrogen-production mix and operational behaviour of each hydrogen-production plant separately. The model then allows gaining valuable insights in the importance of storage and the influence of fuel prices and carbon taxes with regard to the development of an early hydrogen economy. [Copyright &y& Elsevier]

Abstract: The paper presents key results of the studies on energy-technology installations for combined coal-based production of hydrogen and electricity. Special attention is paid to the development of systems, as part of ETI, for cryogenic removal of CO2 from combustion products. Consideration is given to the issues of mathematical modeling of the installations and nonlinear technical and economic optimization of their parameters with regard to investments in the CO2 removal systems. Comparison of efficiency of ETI for hydrogen production and ETI for production of alternative energy carriers (methanol and dimethyl ether) with CO2 removal is presented. [Copyright &y& Elsevier]

Abstract: This paper presents the results of a theoretical investigation whose aim was the development of a simulation tool for performance prediction of a steam reforming hydrogen production plant, and particularly of its overall energetic efficiency. A 1500 Nm3/h hydrogen production plant was simulated. Field data coming from an industrial plant were used for model validation in both design and off design operating conditions. To evaluate the plant performances in terms of energetic efficiency, a particular attention was paid to the simulation of all plant auxiliaries consumptions. Nevertheless the large uncertainty in most of the field data values, the model was able to capture all the relevant phenomena taking place in all the plant components, from reformer reactor up to CO2 sequestration unit, in the investigated plant capacity range (40–100%). [Copyright &y& Elsevier]

Abstract: In this paper hydrogen production via reforming of ethanol has been studied in a novel hybrid plant consisting in a ethanol reformer and a concentrating solar power (CSP) plant using molten salt as heat carrier fluid. The heat needed for the reforming of ethanol has been supplied to the system by molten salts heated up by solar energy. The molten salt stream temperature drop for supplying hydrogen production process heat duty is less than 20K, making the molten salt stream still suitable for steam and electricity production in a co-generative plant (clean hydrogen and electricity). A 2D mathematical model has been formulated, validated and used in order to simulate the performance of the reformer coupled with heat integration through molten salt. Firstly, the effect of operating conditions on the ethanol conversion and on hydrogen production have been evaluated in order to find the optimal conditions for the solar reforming reaction. Then, a reactor design is proposed in order to achieve almost complete ethanol conversion. The results show that the hybrid plant proposed here is a good solution for “green” hydrogen production. Almost complete conversion (99%) can be achieved with an optimized set of operating conditions (GHSV=1115h−1, Pressure=10 bar, steam-to-carbon ratio=5, inlet reactants temperature=823K) and with a 4.5m long reactor. [Copyright &y& Elsevier]

Abstract: In this paper, specific cases for the interaction between the future electricity-generation mix and a newly-developing hydrogen-production infrastructure is modelled with the model E-simulate. Namely, flexible integrated-gasification combined-cycle units (IGCC) are capable of producing both electricity and hydrogen in different ratios. When these units are part of the electricity-generation mix and when they are not operating at full load, they could be used to produce a certain amount of hydrogen, avoiding the costly installation of new IGCC units for hydrogen production. The same goes for the massive introduction of renewable energies (especially wind), possibly generating excess electricity from time to time, which could then perhaps be used to produce hydrogen electrolytically. However, although contra-intuitive, the interaction between both ‘systems’ turns out to be almost negligible. Firstly, it is shown that it is more beneficial to use IGCC facilities to produce hydrogen with, rather than (excess) wind-generated electricity due to the necessary electrolyser investment costs. But even flexible IGCC facilities do not seem to contribute substantially to the early development of a hydrogen economy. Namely, in most scenarios – which are combinations of a wide range of fuel prices and carbon taxes – one primary-energy carrier (natural gas or coal) seems to be dominant, pushing the other, and the corresponding technologies such as reformers or IGCCs, out of the market. [Copyright &y& Elsevier]

Abstract: The objective of this paper is to mathematically model a stand-alone renewable power system, referred to as “Photovoltaic–Fuel Cell (PVFC) hybrid system”, which maximizes the use of a renewable energy source. It comprises a photovoltaic generator (PV), a water electrolyzer, a hydrogen tank, and a proton exchange membrane (PEM) fuel cell generator. A multi-domain simulation platform Simplorer is employed to model the PVFC hybrid systems. Electrical power from the PV generator meets the user loads when there is sufficient solar radiation. The excess power from the PV generator is then used for water electrolysis to produce hydrogen. The fuel cell generator works as a backup generator to supplement the load demands when the PV energy is deficient during a period of low solar radiation, which keeps the system''s reliability at the same level as for the conventional system. Case studies using the present model have shown that the present hybrid system has successfully tracked the daily power consumption in a typical family. It also verifies the effectiveness of the proposed management approach for operation of a stand-alone hybrid system, which is essential for determining a control strategy to ensure efficient and reliable operation of each part of the hybrid system. The present model scheme can be helpful in the design and performance analysis of a complex hybrid-power system prior to practical realization. [Copyright &y& Elsevier]