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Effect of hydrogen addition on the catalytic combustion of fuel-lean carbon monoxide-air mixtures over platinum for micro-scale power generation applications

Chen J., Yan L., Song W., Xu D.

Journal of Power Technologies

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2018

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Vol. 98, nr 1

161--169

EN

The catalytic combustion of hydrogen and carbon monoxide over Pt/γ-Al2O3 catalyst was investigated numerically for H2/CO/O2/N2 mixtures with overall lean equivalence ratios ϕ = 0.117 .. 0.167, H2:CO molar ratios 1:1.5 .. 1:6, a pressure of 0.6 MPa, and a surface temperature range from 600 to 770 K relevant for micro-scale turbines and large gas turbine based power generation systems. Simulations were carried out with a two-dimensional CFD (Computational Fluid Dynamics) model in conjunction with detailed hetero-/homogeneous kinetic schemes and transports to explore the impact of hydrogen addition on catalytic combustion of carbon monoxide. The detailed reaction mechanisms were constructed by implementing recent updates to existing kinetic models. The simulation results indicated that the hydrogen addition kinetically promotes the catalytic combustion of carbon monoxide at wall temperatures as low as 600 K, whereby the catalytic reactions of hydrogen are fully lit-off and the conversion of carbon monoxide is mixed transport/kinetically controlled. Such a low temperature limit is of great interest to idling and part-load operation in large gas turbines and to normal operation for recuperative micro-scale turbine systems. Kinetic analysis demonstrated that the promoting impact of hydrogen addition on catalytic combustion of carbon monoxide is attributed to the indirect effect of hydrogen reactions on the surface species coverage, while direct coupling steps between hydrogen and carbon monoxide are of relatively minor importance. The added hydrogen inhibits the catalytic oxidation of carbon monoxide for wall temperatures below 520 K, which are well below the minimum inlet temperatures of reactants in micro-scale turbine based power generation systems.

2

A study and application of high-resolution methods for reef reservoir identification

Yan L., Cheng B., Xu T., Wei S., Qian Z.

Acta Geophysica

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2017

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Vol. 65, no. 5

907--917

EN

Reefs represent a special type of carbonate trap that plays a key role in the migration, accumulation, and formation of a reservoir. They have commonly been the targets of exploration and development. However, reefs have complex interior structures and easily grow as thin, interbedded geological frames with reef microfacies that include the cap, core, and base of the reef. Because of the inherent drawbacks of seismic signals, including their low frequencies and narrow bandwidths, it is difficult to accurately identify reef reservoirs. Fortunately, the seismic frequency, phase, energy, waveform and other dynamic and geometrical properties can be used to compensate for the energy, expand the frequency bandwidth, and decompose and reconstruct the wavelet to obtain high-resolution seismic data. These data can highlight certain seismic responses of reefs, including boundary reflections, dome-shaped reflections from the reef outline, strong reflections from the reef cap, reflections from the reef bottom, and onlap reflections from the reef flanks. Some impedance response regularities, such as the lower impedance of the reef cap relative to the reef core and biodetritus beach and the fluctuating impedance of the reef-flat complex, are observed by combining log data with geological and high-resolution seismic data for a reef reservoir inversion. These methods were applied to the Changxing Formation in the Yuanba Gas Field. Good prediction results were obtained with a high consistency between the log and seismic data in a comparative analysis with the original seismic data and well logs.

3

Desensitization by Pre-shocking in Heterogeneous Explosives and its Numerical Modelling

Hussain T., Yan L., Fenglei H., Yi L.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 2

357--379

EN

Desensitization caused by pre-shocking in heterogeneous explosives is discussed. The aim of this study was to find a simple numerical model that could reproduce the important features of previously reported shock desensitization experiments. After reviewing the previous experimental results and modelling efforts, an extension of the Lee-Tarver reactive flow model is proposed. The proposed desensitization model is based upon the experimentally determined desensitization criteria for explosives. The additional parameters required for this extension can be calibrated by experiment for a typical explosive. The new model has been implemented in the hydrodynamic code LS-DYNA as a user defined equation of state, and is now available to simulate various kinds of situations involving explosives up to the limits and capabilities of LS-DYNA. Desensitization by pre-shocking in double shock experiments, reflected shock and detonation quenching experiments have been studied using the new model, and the results were found to be in qualitative agreement with the experimental results reported in the literature.

4

Współspalanie biomasy

Higgins B., Yan L., Gadalla H., Meier J., Fareid T., Liu G., Milewicz M., Repczyński A., Ryding M., Błasiak W.

Energetyka Cieplna i Zawodowa

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2010

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Nr 2

58--62

PL

Współspalanie biomasy z węglem sprawia, że emisja gazów cieplarnianych spada o blisko połowę. W artykule prezentuję system spalania objętościowego (ROFA), pozwalającego na spalanie dużych ilości biomasy z węglem.