Oxidative reforming of methane for hydrogen and synthesis gas production:Thermodynamic equilibrium analysis

A thermodynamic analysis of methane oxidative reforming was carried out by Gibbs energy minimization （at constant pressure and temperature） and entropy maximization （at constant pressure and enthalpy） methods,to determine the equilibrium compositions and equilibrium temperatures,respectively.Both cases were treated as optimization problems （non-linear programming formulation）.The GAMS 23.1 software and the CONOPT2 solver were used in the resolution of the proposed problems.The hydrogen and syngas production were favored at high temperatures and low pressures,and thus the oxygen to methane molar ratio （O 2 /CH 4） was the dominant factor to control the composition of the product formed.For O 2 /CH 4 molar ratios higher than 0.5,the oxidative reforming of methane presented autothermal behavior in the case of either utilizing O 2 or air as oxidant agent,but oxidation reaction with air possessed the advantage of avoiding peak temperatures in the system,due to change in the heat capacity of the system caused by the addition of nitrogen.The calculated results were compared with previously published experimental and simulated data with a good agreement between them.

Effect of O_2/CH_4ratio on the optimal specific-energy-input (SEI) for oxidative reforming of biogas in a plasma-shade reactor

In a novel plasma-shade reactor for oxidative reforming of biogas(CH4/CO2=3/2),the effects of specific-energy-input (SEI) on CH4 and CO2 conversions and energy cost of syngas were investigated at O2/CH4ratios ranged from 0.42 to 0.67.At each of O2/CH4 ratios,V-shape profiles of energy cost of syngas increasing with SEI were observed,reaching the lowest value at the optimal SEI(Opt-SEI).With the increase of O2/CH4 ratio,the Opt-SEI decreased significantly.Moreover,at the Opt-SEI,O2 and CH4 conversions and dry-basis concentration of syngas increased and energy cost of syngas decreased greatly with the increase of O2/CH4 ratio.

Low CO content hydrogen production from oxidative steam reforming of ethanol over CuO-CeO_2 catalysts at low-temperature

CuO-CeO2 catalysts were prepared by a urea precipitation method for the oxidative steam reforming of ethanol at low-temperature.The catalytic performance was evaluated and the catalysts were characterized by inductively coupled plasma atomic emission spectroscopy,X-ray diffraction,temperature-programmed reduction,field emission scanning electron microscopy and thermo-gravimetric analysis.Over CuOCeO2 catalysts,H2 with low CO content was produced in the whole tested temperature range of 250–450 C.The non-noble metal catalyst 20CuCe showed higher H2production rate than 1%Rh/CeO2 catalyst at 300–400 C and the advantage was more obvious after 20 h testing at400 C.These results further confirmed that CuO-CeO2 catalysts may be suitable candidates for low temperature hydrogen production from ethanol.

Reforming of CH_4 with CO_2 over Co/Mg–Al oxide catalyst

A series of Co/Mg-Al oxide samples, CoMgAl-x （x = （Mg ＋ Co）]AI molar ratio of 1-5）, were prepared by the self-combustion method followed by H2 reduction. The catalytic performance and stability of the samples were studied in dry reforming ofCH4. XRD and H2-TPR characterization results showed that the reduced CoMgAl-x samples mainly consisted of solid solution and spinel phases with cobalt particles. The spinel phases contained COB04 and ConMgl-nAl204 （0 〈 n 〈 1 ） varying with the （Mg ＋ Co）/AI ratio, The effect of （Mg ＋ Co）/A1 molar ratio on the catalytic behavior was investigated in detail and CoMgAI-3 exhibited the highest catalytic activity and stability among the catalysts studied.

Renewable hydrogen production from butanol:a review

Hydrogen production from butanol is a promising alternative when it is obtained from bio-butanol or bio-oil due to the higher hydrogen content compared to other oxygenates such as methanol,ethanol or propanol.Catalysts and operating conditions play a crucial role in hydrogen production.Ni and Rh are metals mainly used for butanol steam reforming,oxidative steam reforming and partial oxidation.Additives such as Cu can improve catalytic activity in many folds.Moreover,support-metal interaction and catalyst preparation technique also play a decisive role in the stability and hydrogen production capacity of catalyst.Steam reforming technique as an option is more frequently researched due to higher hydrogen production capability in comparison to other thermochemical techniques despite its endothermic nature.The use of the oxidative steam reforming and partial oxidation has the advantages of requiring less energy and longer stability of catalysts.However,the hydrogen yield is less.This article brings together and examines the latest research on hydrogen production from butanol via steam reforming,oxidative steam reforming and partial oxidation reactions.In addition,the review examines a few thermodynamic studies based on sorption-enhanced steam reforming and dry reforming where there is potential for hydrogen extraction.