Integration of a light mobility urban scale hydrogen refuelling station for cycling purposes in the transportation market

Road transportation consists of a significant contributor to total greenhouse gas emissions in developed countries. New alternative technologies in transportation such as electric vehicles aim to reduce substantially vehicle emissions, particularly in urban areas. Incentives of using two-wheel electric vehicles such as bicycles in big cities centres are promoted by local governments, and in fact, some countries are already trying to adopt this transition. An interesting case consists of the use of hydrogen fuel cells in such vehicles to increase their driving range under short refuelling times. To this end, this paper investigated the social and financial prospects of hydrogen infrastructure for city-oriented fuel cell electric vehicles such as bicycles. The results of the research indicated that a light mobility urban hydrogen refuelling station able to provide refuelling processes at pressures of 30 bar with a hydrogen fuel cost of 34.7 €/kgH₂ is more favourable compared to larger stations.     

Optimization of anode performance in the ethanol electrochemical reforming for clean hydrogen production

Carbon-based fuel electrochemical reforming is considered as a promising hydrogen production method. Ethanol is one of the most appropriate carbon-based fuels. In this work, anode performance, especially the flow, ethanol electro-oxidization and energy consumption in the ethanol electrochemical reforming is numerically studied and experimental verified. Take the straight serpentine channel with square cross-section as a base structure in the electrochemical cell (EC), the effects of channel geometry and operating parameters are analyzed. Another five different configurations of flow channels, as well as another three different cross-sections are designed and explored. Results indicate that at the same cross-section area, the wider channel provides the higher effective area for proton transfer, and thereby improves the electrode reactions. The appropriate decrease of inlet velocity or increase of input voltage promotes the anode reaction and reduces the pressure drop in channel, while the operating temperature has the opposite effects on ethanol conversion and pressure drop. The arc channel is found optimal considering its highest ethanol conversion, although its pressure drop is a bit higher. The sector cross-section with uniform flow field distribution is found most favorable for the straight serpentine channel considering the ethanol electro-oxidization. These findings will favor the improvement of EC.     

Economics of hydrogen production and utilization strategies for the optimal operation of a grid-parallel PEM fuel cell power plant

This paper integrates the hydrogen production and utilization strategies with an economic model of a PEM fuel cell power plant (FCPP). The model includes the operational cost, thermal recovery, power trade with the local grid, and hydrogen management strategies. The model is used to determine the optimal operational strategy, which yields the minimum operating cost. The optimal operational strategy is achieved through estimation of the following: hourly generated power, thermal power recovered from the FCPP, power trade with the local grid, and hydrogen production. An evolutionary programming-based technique is used to solve for the optimal operational strategy. The model is tested using different seasonal load demands. The results illustrate the impact of hydrogen management strategies on the operational cost of the FCPP when subjected to seasonal load variation. Results are encouraging and indicate viability of the proposed model.     

Optimization of hydrogen feeding procedure in PEM fuel cell systems for transportation

The hydrogen feeding sub-system is one of balance of plant (BOP) components necessary for the correct operation of a fuel cell system (FCS). In this paper the performance of a 6 kW PEM (Proton Exchange Membrane) FCS, able to work with two fuel feeding procedures (dead-end or flow-through), was experimentally evaluated with the aim to highlight the effect of the anode operation mode on stack efficiency and durability. The FCS operated at low reactant pressure (<50 kPa) and temperature (<330 K), without external humidification. The experiments were performed in both steady state and dynamic conditions. The performance of some cells in dead-end mode worsened during transient phases, while a more stable working was observed with fuel recirculation. This behavior evidenced the positive role of the flow-through procedure in controlling flooding phenomena, with the additional advantage to simplify the management issues related to hydrogen purge and air stoichiometric ratio. The flow-through modality resulted a useful way to optimize the stack efficiency and to reduce the risks of fast degradation due to reactant starvation during transient operative phases.     

High yield hydrogen production from low CO selectivity ethanol steam reforming over modified Ni/Y2O3 catalysts at low temperature for fuel cell application

Ethanol–water mixtures were converted directly into H₂ with 67.6% yield and >98% conversion by catalytic steam reforming at 350 °C over modified Ni/Y₂O₃ catalysts heat treated at 500 °C. XRD was used to test the structure and calculate the grain sizes of the samples with different scan rates. The initial reaction kinetics of ethanol over modified and unmodified Ni/Y₂O₃ catalysts were studied by steady state reaction and a first-order reaction with respect to ethanol was found. TPD was used to analyze mechanism of ethanol desorption over Ni/Y₂O₃ catalyst. Rapid vaporization, efficiency tube reactor and catalyst were used so that homogeneous reactions producing carbon, acetaldehyde, and carbon monoxide could be minimized. And even no CO detective measured during the first 49 h reforming test on the modified catalyst Ni/Y₂O₃. This process has great potential for low cost H₂ generation in fuel cells for small portable applications where liquid fuel storage is essential and where systems must be small, simple, and robust.     

Dry reforming of ethanol for hydrogen production: Thermodynamic investigation

Thermodynamics of ethanol reforming with carbon dioxide for hydrogen production has been studied by Gibbs free energy minimization method. The optimum conditions for hydrogen production are identified: reaction temperatures between 1200 and 1300 K and carbon dioxide-to-ethanol molar ratios of 1.2–1.3 at 0.1 MPa. Under the optimal conditions, complete conversion of ethanol, 94.75–94.86% yield of hydrogen and 96.77–97.04% yield of carbon monoxide can be achieved in the absence of carbon formation. The ethanol reforming with carbon dioxide is suitable for providing hydrogen-rich fuels for molten carbonate fuel cell and solid oxide fuel cell. The carbon-formed and carbon-free regions are found, which are useful in guiding the search for suitable catalysts for the reaction. Inert gases have a positive effect on the hydrogen and carbon monoxide yields.     

Thermodynamic analysis of hydrogen production by autothermal reforming of ethanol

Ethanol steam reforming (ESR) is a strong endothermic reaction and ideally it only produces hydrogen and carbon dioxide.     

Ni-hydrocalumite derived catalysts for ethanol steam reforming on hydrogen production

Hydrocalumite derived catalysts prepared by co-precipitation with non-noble metal Nickel(Ni) as main active site were tested in ethanol steam reforming, and the influences of Ni (5,10,15 wt%) content were mainly tested in this research. Meanwhile, the physicochemical properties of the prepared catalysts were analyzed through different characterizations including BET, X-ray diffraction (XRD), H₂-temperature programmed reduction (H₂-TPR) and CO₂-temperature programmed desorption (TPD). As the Ni increased, the specific surface area, crystallite size of Ni, reducibility and basicity of catalysts were changed, which further affected their activities. On this basis, the best performance in this catalytic system was presented when Ni in the catalysts was 15 wt%, the ethanol conversion and hydrogen yield could reach almost 100% and 85% at 650 °C respectively. Thus, this kind of catalyst is effective for ethanol steam reforming.     

Effect of molar ratio of water / ethanol on hydrogen selectivity in catalytic production of hydrogen using steam reforming of ethanol

As fossil energy resources are shrinking, the increase in global energy needs and environmental pollution paved the way to the search for new and renewable energy resources. Therefore, the future of energy technology is being built on the use of hydrogen, which is one of the cleanest and most efficient renewable energy sources, and steam reforming is becoming the utmost method to produce hydrogen. This study focuses on the operation condition of steam reforming of ethanol on catalyst materials, which were shaped using active metals such as Ni, Cu and Cs and supporting materials which were activated by carbon and LiAlO₂. These catalyst materials were tested to produce hydrogen gas using different water/ethanol mole ratio at different temperatures and a constant feed flow rate. The evaluation regarding hydrogen selectivity results and the percentage of hydrogen in the products revealed that NiCuCs/LiAlO₂ catalyst showed the highest performance at all water/ethanol ratios and temperatures between 300 and 600 °C.     

Renewable energy for hydrogen production and sustainable urban mobility

In recent years, the number of power plants based on renewable energy (RWE) has been increasing and hydrogen as an energy carrier has become a suitable medium-to-long term storage solution as well as a “fuel” for FCEV's because of its CO₂-free potential.     

Regenerable and durable catalyst for hydrogen production from ethanol steam reforming

In this work, perovskite-type oxides La_1−xCa_xFe_0.7Ni_0.3O₃ were prepared by using a citrate complex method. The catalysts were employed in the reactions of steam reforming of ethanol (SRE) and oxidative steam reforming of ethanol (OSRE) to produce hydrogen. A reduction-oxidation cycle was proposed to overcome the problems of active component sintering and carbon deposition encountered in SRE reaction. In the ex-situ reactions, highly dispersed surface nickel particles formed during the reduction of La_1−xCa_xFe_0.7Ni_0.3O₃, while during the introduction of an oxidative atmosphere these particles could be oxidized and restored back into the perovskite bulk. Owing to the existence of this segregation-incorporation cycle of nickel species in the perovskite oxides, the sintering of nickel particles under OSRE was found depressed effectively. Besides, this work proved that the oxygen in the feed is helpful to the elimination of deposited carbon. It seems promising for overcoming the problems of the active component sintering and carbon deposition in SRE reaction by regulating the redox ability of the perovskite-type oxides and the feed composition.     

Large capacity hydrogen production by microwave discharge plasma in liquid fuels ethanol

In situ hydrogen production technologies have attracted attentions because of hydrogen storage and transportation safety issues. Discharge plasma technology for hydrogen production is of fast response, large capacity, small scale and portability, which is suitable for automobiles and ships. In this paper, a method for producing hydrogen by microwave discharge in ethanol solution was introduced. A microwave discharge reactor of direct standing wave coupling (MDRSWC) was designed, which was suitable for on-board hydrogen production. The characteristics of large capacity hydrogen production by applying MDRSWC in liquid ethanol were investigated. Depending on the experimental conditions of ethanol concentration and microwave power, the flow rate of hydrogen production was achieved ranging from 28.93 to 72.48 g/h. In addition to main hydrogen and carbon dioxide, a small amount of methane and acetylene as by-products were detected. By optimizing the experimental conditions, the experimental results showed that the flow rate of hydrogen, the percentage concentration of hydrogen and the energy yield of hydrogen production were 72.48 g/h, 58.1% and 48.32 g/kWh respectively. This work could provide a potentially effective hydrogen production method for on-board hydrogen utilization device.     

Study of a CeZrCoRh mixed oxide for hydrogen production by ethanol steam reforming

The catalytic activity of Ce₂Zr_1.5Co_0.47Rh_0.07O_8−δ oxide has been studied in the reaction of ethanol steam reforming. The catalyst has been characterised by XRD, SEM, TEM-EDXS, IR operando, TPR and TPO techniques. The results show that there are three main causes of catalyst deactivation. The first one is the accumulation of carbonates species leading to the blocking of active sites. This phenomenon is partially reversible by high temperature treatment under inert gas flow. The second deactivation mechanism is the formation of carbonaceous deposits. It has been shown to be directly proportional to the quantity of ethanol converted during the ethanol steam reforming, and produced with a constant selectivity whatever the ethanol conversion level, it is irreversible by thermal cleaning. The third way of deactivation arises from a structural change of the catalyst under the reaction conditions, which gradually loses its redox capacity.     

Co catalysts modified by rare earths (La,Ce or Pr) for hydrogen production from ethanol

Co/MgAl₂O₄ catalysts modified with La, Pr or Ce were prepared, characterized by different techniques and tested in ethanol steam reforming reaction to produce hydrogen. The catalytic behavior at 650 °C depended on the nature of rare earth. The amount of carbon on promoted catalysts was significantly lower than that on unpromoted one. The Pr and La containing catalysts produced a high acetaldehyde selectivity which decreased the hydrogen production. The superior performance of the catalyst promoted with 7.8% Ce could be partially explained by a higher dispersion and a high reduction of Co species.     

Preliminary hazard identification for risk assessment on a complex system for hydrogen production

Renewable power generation facilities are constantly expanding due to the expected depletion of fossil fuels and the increasingly demanding policy of pollution control. Having said that, hydrogen is one of the promising energy sources. That said, hydrogen chain safety is an unescapable parameter that should continuously coexist with the development of hydrogen domain. In this context, this article presents a contribution to the risk analysis and evaluation of a complex hydrogen production system 'EGA-9000′ at CIEMAT (Centre for Research on Energy, Environment and Technology - Madrid, Spain). The methodology followed in this study revolves around the risk analysis process through a FAST (Functional Analysis System Technique) functional analysis method and a HAZOP (HAZard and Operability) dysfunctional analysis method. The evaluation of the thirty-three scenarios identified by the risk analysis shows that the studied system is insecure. Indeed, five scenarios at an unacceptable level of risk. And it is noted that the risk of fire and explosion is the major risk for all scenarios studied. To this end, safety measures (recommendation) have been proposed based on the weaknesses detected by the risk analysis carried out.     

Highly purified hydrogen production from ammonia for PEM fuel cell

Liquid ammonia is an attractive hydrogen carrier because of high storage capacity. According to ISO14687-2, an acceptable ammonia concentration in hydrogen for polymer electrolyte membrane (PEM) fuel cell vehicles is 0.1 ppm. When ammonia is used as the hydrogen carrier, about 1000 ppm of ammonia included in gas generated by ammonia decomposition at 773–823 K and 0.1 MPa has to be reduced to less than 0.1 ppm. Although several types of ammonia absorption materials are investigated as ammonia remover, the target value cannot be achieved by static adsorption methods. However, we have succeeded in that the ammonia concentration is reduced down to 0.01–0.02 ppm by using Li-exchange X-type zeolite (Li-X) as the absorbent and dynamic adsorption methods. Furthermore, Li-X is simply recycled by heating at 673 K. Therefore, Li-X is a durable and recyclable ammonia removal material for the highly purified hydrogen production from ammonia for PEM fuel cells.     

Dynamic competition between plug-in hybrid and hydrogen fuel cell vehicles for personal transportation

This article addresses the issue of the diffusion of hydrogen cars in the market, particularly the competition with electric cars for the replacement of conventional vehicles. Using the multi-technological competition model developed by Le Bas and Baron-Sylvester’s (Diffusion technologique non binaire et schéma épidémiologique. Une reconsidération. Economie Appliquée 1995; tome XLVIII(3):71–101), it is shown that the early deployment of plug-in hybrid vehicles—the only electric technology which can compete with fuel cell cars in the multipurpose vehicle field—risks closing the market for hydrogen in the future. Moreover, the advent of the hydrogen vehicle depends on the rapid advancements in fuel cell technologies, as well as on the existence of an infrastructure with a sufficient coverage.     

Direction of glucose fermentation towards hydrogen or ethanol production through on-line pH control

The present study investigated the production of hydrogen (H₂) and ethanol from glucose in an Anaerobic Continuous Stirred Tank Reactor (ACSTR). Effects of hydraulic retention time (HRT) and pH on the preference of producing H₂ and/or ethanol and other soluble metabolic products in an open anaerobic enriched culture were studied. Production rates of H₂ and ethanol increased with the increase of biomass concentration. Open anaerobic fermentation was directed and managed through on-line pH control for the production of H₂ or ethanol. Hydrogen was produced by ethanol and acetate-butyrate type fermentations. pH has strong effect on the H₂ or ethanol production by changing fermentation pathways. ACSTR produced mainly ethanol at over pH 5.5 whereas highest H₂ production was obtained at pH 5.0. pH 4.9 favored the lactate production and accumulation of lactate inhibited the biomass concentration in the reactor and the production of H₂ and ethanol. The microbial community structure quickly responded to pH changes and the Clostridia dominated in ACSTR during the study. H₂ production was maintained mainly by Clostridium butyricum whereas in the presence of Bacillus coagulans glucose oxidation was directed to lactate production.     

A processing scheme for industrial ethanol production from straw

We describe a model for the industrial production of ethanol, using wheat straw as a raw material, for use in automobiles as a fuel mixed with gasoline. In particular for Greece, we have in mind that wheat straw production of the Thessalia Plain.The energy requirements of the factory are covered totally by burning the produced lignin. Particularly, the electric energy needs are covered by an electric generator which consumes part of the thermal energy produced by the combustion of lignin.The fermentable sugars are obtained from cellulose by hydrolysis, using an enzymatic system of cellulases which are produced from a cultivation of Trichoderma viride.The cellulose is separated from the lignin by heating the straw at 100°C, in water solution of NaOH 1%.We propose a fast fermentation method in order to reduce the cost, and the rejected/24 hr yeast from the Laval separators is processed for the production of a protein-containing animal food (8 kg of pressed yeast per 1001 of alcohol).We give the mass and energy balance and the cost, in current prices, of the produced ethanol, which is estimated to be 7.9 Dr ($0.19 U.S.) per liter. We also estimate that the plant cost will be about 20 million dollars for a production capacity of 100 thousand litres of ethanol per day.     

Cobalt-based nanoparticles as catalysts for low temperature hydrogen production by ethanol steam reforming

Results obtained in the synthesis, characterization and application as catalyst of cobalt nanoparticles are reported. Cobalt nanoparticles were prepared via reduction method in aqueous solution. Structural characterization was carried out using X-ray diffraction (XRD), morphological studies were performed with a scanning electron microscope equipped with a field emission gun (FE-SEM). A DC-superconducting quantum interference device “SQUID” magnetometer was used to measure the room temperature (RT) magnetic hysteresis cycle in the −5 ÷ 5 Tesla (T) μ₀H magnetic field range as well as magnetization as a function of temperature. This material is constituted by very small primary particles (∼2.8 nm radius) which appear amorphous to XRD and have a superparamagnetic behaviour. However, annealing at 773 K and also utilization in the catalytic reactor at the same temperature result in XRD detectable cubic Co nanocrystals. These unsupported cobalt nanoparticles were found catalytically active in the ethanol steam reforming reaction, producing hydrogen with 90% yield at 773 K. These nanoparticles show a better catalytic behaviour compared to those of more conventional Co and Ni based catalysts, due to very low CO and methane production, and with moderate formation of carbonaceous materials.