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Hydrocarbon Fuels (hydrocarbon + fuel)
Selected AbstractsHydrogen utilization as a fuel: hydrogen-blending effects in flame structure and NO emission behaviour of CH4,air flameINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 5 2007Jeong Park Abstract Hydrogen-blending effects in flame structure and NO emission behaviour are numerically studied with detailed chemistry in methane,air counterflow diffusion flames. The composition of fuel is systematically changed from pure methane to the blending fuel of methane,hydrogen through H2 molar addition up to 30%. Flame structure, which can be described representatively as a fuel consumption layer and a H2,CO consumption layer, is shown to be changed considerably in hydrogen-blending methane flames, compared to pure methane flames. The differences are displayed through maximum flame temperature, the overlap of fuel and oxygen, and the behaviours of the production rates of major species. Hydrogen-blending into hydrocarbon fuel can be a promising technology to reduce both the CO and CO2 emissions supposing that NOx emission should be reduced through some technologies in industrial burners. These drastic changes of flame structure affect NO emission behaviour considerably. The changes of thermal NO and prompt NO are also provided according to hydrogen-blending. Importantly contributing reaction steps to prompt NO are addressed in pure methane and hydrogen-blending methane flames. Copyright © 2006 John Wiley & Sons, Ltd. [source] An optimized kinetics model for OH chemiluminescence at high temperatures and atmospheric pressuresINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 12 2006Joel M. Hall Chemiluminescence from the OH(A , X) transition near 307 nm is a commonly used diagnostic in combustion applications such as flame chemistry, shock-tube experiments, and reacting-flow visualization. Although absolute measurements of OH(X) concentrations are well defined, there is no elementary relation between emission from the electronically excited state (OH*) and its absolute concentration. Thus, to enable quantitative emission measurements, a kinetics model has been assembled and optimized to predict OH* formation and quenching at combustion conditions. Shock-tube experiments were conducted in mixtures of H2/O2/Ar, CH4/O2/Ar, and CH4/H2/O2/Ar with high levels of argon dilution (>98%). Elementary reactions to model OH*, along with initial estimates of their rate coefficients, were taken from the literature. The important formation steps follow: (R0) (R1) Sensitivity analyses were performed to identify experimental conditions under which the shape of the measured OH* profiles and the magnitude of the OH* emission would be sensitive to the formation reactions. A fitting routine was developed to express the formation rate parameters as a function of a single rate, k1 at the reference temperature (1490 K). With all rates so expressed, H2/CH4 mixtures were designed to uniquely determine the value of k1 at the reference temperature, from which the remaining rate parameters were calculated. Quenching rates were fixed at their literature values. The new model predicts the experimental data over the range of conditions studied and can be used to calibrate the emission diagnostic for other applications, such as measurements in real combustion environments, containing higher order hydrocarbon fuels and lower levels of dilution in air. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 714,724, 2006 [source] Novel nickel-based catalyst for low temperature hydrogen production from methane steam reforming in membrane reformerASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010Yazhong Chen Abstract Hydrogen production from various hydrocarbon fuels, particularly biomass-derived fuels, has attracted worldwide attention due to its potential for application to fuel cells, a device which converts chemical energy into electricity efficiently and cleanly. However, current technology, such as natural gas steam reforming, could not meet the specific requirements of hydrogen for fuel cells. Therefore, novel processes are intensively investigated, aiming to develop economic and efficient ones for the specific purpose. An important direction is the integrated membrane reformer for one-step high-purity hydrogen production. However, for the commercial realization of this technology, there are still some difficulties to overcome. By comparison with previous investigations with a similar membrane, this work showed that catalyst also played an important role in determining membrane reformer performance. We proposed that when thickness of membrane was several micrometers, the permeance of membrane became less important than the kinetics of catalyst, due to the fact that under such conditions, hydrogen permeation rate was faster than the kinetics of steam reforming reaction when commercial catalyst was applied, but further evidence is indispensable. In this initial work, we focused on developing efficient nickel catalyst for low temperature steam reforming. Nickel-based catalyst was developed by deposition,coprecipitation and used as pre-reduced, showing high performance for methane steam reforming at low temperatures and good durability, which may find practical application for the integrated membrane reforming process. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Investigation of Soot Formation During Partial Oxidation of Diesel FuelCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2007K. Roth Abstract Soot formation during partial oxidation is a major issue for hydrogen production from liquid hydrocarbon fuels. Measurements were made to investigate the sooting behavior of diesel fuel under variation of the main operating parameters temperature (T = 800 to 1300,°C), pressure (p = 1 to 3,bar), equivalence ratio (, =1 to 3), and steam ratio (H2O/C = 0.2 to 0.6) at constant residence time. The experimental setup was a perfectly stirred/plug flow reactor (PSR/PFR system) providing conditions close to reality. The study proves that soot growth rate strongly depends on temperature, pressure, and equivalence ratio while adding water has a minor effect on soot growth. Experimental results were compared with a kinetic model developed by the Institut Français du Pétrole (IFP), predicting soot formation during the partial oxidation of liquid hydrocarbon fuels. The calculated amount of soot shows good agreement with the measured data. [source] Effect of Oxygen on Methane Steam Reforming in a Sliding Discharge ReactorCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2006F. Ouni Abstract Hydrogen-rich gas can be efficiently produced in compact plasma reformers by the conversion of a variety of hydrocarbon fuels, including natural gas and gasoline. This article describes experimental and modeling progress in plasma reforming of methane using a sliding discharge reactor (SDR). Experiments have been carried out in a compact device operating at low consumed power (1,2,kW). Previous studies of methane steam reforming using a SDR at atmospheric pressure show promising results (H2 concentration higher than 55,%). In order to study the effect of oxygen on the methane conversion and thus hydrogen production, a small amount of oxygen in the range of 7,20,% was added to the CH4 -H2O mixture. An unexpected result was that under our experimental conditions in the SDR oxygen did not have any influence on the methane conversion. Almost the totality of added oxygen is recovered intact. Moreover, part of the H2 produced was transformed into water by reaction with O2. A model describing the chemical processes based on classical thermodynamics is also proposed. The results indicate that the reactor design has to be improved in order to increase conversion and hydrogen production. [source] | ||||||||||