An experimental investigation of biodiesel steam reforming

Recently, liquid biofuels have attracted increasing attention as renewable feedstock for hydrogen production in the transport sector. Since the lack of hydrogen infrastructure and distribution poses an obstacle for the introduction of fuel cell vehicles to the market, it is reasonable to consider using liquid biofuels for on-board or on-site hydrogen generation. Biodiesel offers the advantage of being an environmentally friendly resource while also having high gravimetric and volumetric energy density. The present study constitutes an experimental investigation of biodiesel steam reforming, the main emphasis of which is placed on finding optimum operating conditions in order to avoid catalyst deactivation. Temperature was varied from 600 °C to 800 °C, pressure from 1 bar to 5 bar and the molar steam-to-carbon ratio from 3 to 5. Based on the experimental results, coke formation and sintering are identified as the main deactivation mechanisms. Initiation of catalyst deactivation primarily depends on catalyst inlet temperature and feed mass flow per open area of catalyst. By using a metallic based precious metal catalyst, applying low feed flow rates (31 g/h∙cm2) and a sufficiently high catalyst inlet temperature (>750 °C) coking can be minimized, thus avoiding catalyst deactivation. A stable product gas composition close to chemical equilibrium has been achieved over 100 h with a biodiesel conversion rate of 99%

THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS m ® in an ASME Journal. Authorization to photocopy material for internal or personal use under circumstance not falling within the fair use provisions of the DAMAGE TOLERANCE BASED LIFE PREDICTION IN GAS TURBIN

ABSTRACT A novel fracture mechanics approach has been used to predict crack propagation lives in gas turbine engine blades subjected to vibratory high cycle fatigue (HCF). The vibratory loading included both a resonant mode and a non-resonant mode, with one blade subjected to only the non-resonant mode and another blade to both modes. A life prediction algorithm was utilized to predict HCF propagation lives for each case. The life prediction system incorporates a boundary integral element (BIE) derived hybrid stress intensity solution which accounts for the transition from a surface crack to comer crack to edge crack. It also includes a derivation of threshold crack length from threshold stress intensity factors to give crack size limits for no propagation. The stress intensity solution was calibrated for crack aspect ratios measured directly from the fracture surfaces. The model demonstrates the ability to correlate predicted missions to failure with values deduced from fractographic analysis. This analysis helps to validate the use of fracture mechanics approaches for assessing damage tolerance in gas turbine engine components subjected to combined steady and vibratory stresses

Direct steam reforming of diesel and diesel–biodiesel blends for distributed hydrogen generation

Distributed hydrogen generation from liquid fuels has attracted increasing attention in the past years. Petroleum-derived fuels with already existing infrastructure benefit from high volumetric and gravimetric energy densities, making them an interesting option for cost competitive decentralized hydrogen production. In the present study, direct steam reforming of diesel and diesel blends (7 vol.% biodiesel) is investigated at various operating conditions using a proprietary precious metal catalyst. The experimental results show a detrimental effect of low catalyst inlet temperatures and high feed mass flow rates on catalyst activity. Moreover, tests with a desulfurized dieselebiodiesel blend indicate improved long term performance of the precious metal catalyst. By using deeply desulfurized diesel (1.6 ppmw sulfur), applying a high catalyst inlet temperature (>800 °C), a high steam-to-carbon ratio (S/C = 5) and a low feed mass flow per open area of catalyst (11 g/h cm2), a stable product gas composition close to chemical equilibrium was achieved over 100 h on stream. Catalyst deactivation was not observed

On-site hydrogen production at refuelling stations from diesel and biodiesel

On-site hydrogen production at refuelling stations from liquid fuels offers a number of advantages like high energy density and infrastructure already being available. Besides, it is economically advantageous in areas where hydrogen cannot be cost-effectively supplied by a central production plant. Within the 3-year project NEMESIS2+ (New Method for Superior Integrated Hydrogen Generation System) a small-scale hydrogen generator capable of producing 50 m3h-1 from biodiesel and diesel will be developed. Apart from integrating such system into existing refuelling stations, the NEMESIS2+ hydrogen generator is potentially applicable to the chemical industry, in particular for blanketing, hydrogenation and chemical synthesis

Chemical Looping Reforming for syngas generation at real process conditions in packed bed reactors: an experimental demonstration

Chemical looping reforming (CLR) is a promising technology for syngas production combining autothermal operation with integrated CO2 capture. At large scale, reformer outlet pressure during syngas production is an important factor for the overall plant’s process efficiency and defines the energy requirements for downstream processing. Packed bed reactors are widely used and established in industry for high pressure operating conditions due to their robust and, compared to other reactor types, simpler engineering. In this paper, CLR in packed bed reactors (CLR-PB) is demonstrated under a pressure range of 1 – 5 bar in a lab scale reactor, using NiO/CaAl2O4 as the oxygen carrier (OC). Oxidation, reduction and dry reforming processes were examined in a wide range of temperature (400 – 900 °C), pressure (1 – 5 bar), flowrate (10 – 40 NLPM) and different inlet gas compositions, providing an important foreground for the optimal operating conditions for each process.Furthermore, a full CLR-PB pseudo-continuous cycle has been successfully demonstrated for the first time in a lab reactor setup. During the full cycle operation, CH4 conversion > 99% has been achieved, while the temperature and concentration profiles provided identical results for consecutive cycles verifying the continuity and the feasibility of the process. These results constitute the basis for the scale-up of the process, where heat losses would be minimized and the energy efficiency of the process would be significantly higher

Effect of the nature of the support on the activity of Pt-Sn based catalysts for hydrogen production by dehydrogenation of ultra-low sulphur kerosene Jet A-1

International audienc

Thermochemical syngas generation via solid looping process: An experimental demonstration using Fe-based material

Chemical looping is investigated for the production of syngas via reforming or reverse water gas shift in a packed bed reactor using 500 g of Fe on Al2O3 was demonstrated. Oxidation, reduction of the OC and subsequent catalytic reactions of reforming or reverse water gas shift were examined in a temperature range of 600–900 °C and a pressure range of 1–3 bara at high flowrate. Different inlet gas compositions were explored for the considered gas–solid and catalytic reaction stages. Oxidation with air successfully heated the reactor. CH4 resulted ineffective at reducing the Fe-based oxygen carrier while H2 and CO-rich stream were able to achieve full reduction to FeO of the material. In terms of catalytic activity, the maximum conversion of CH4 achieved during the reforming was limited to 62.8 % at 900 °C and 1 bara.Thermally integrated chemical looping reverse water gas shift was studied as option for CCU in combination with green H2 to produce renewable fuels. A H2/CO value of 2 could be achieved by feeding H2/CO2 of 2. The pressure did not substantially affect the conversion and the bed did not present carbon deposition.The ability of a Fe-based packed bed chemical looping reactor to recover after the carbon deposition was also explored. It was found that using a mixture of CH4 and CO2 achieved 92% recovery of the original capacity