Design of two-stage membrane reactor for the conversion of coke-oven gas to H_2 and CO

The catalyst function was achieved in two regions in an oxygen permeation membrane reactor： H2 dissociated and reacted with lattice oxygen or oxygen ions to form H20 near the membrane surface. The H20 formed could react with the residual CH4 away from the membrane surface area.

Effect of CeO_2 addition on Ni/Al_2O_3 catalysts for methanation of carbon dioxide with hydrogen

The Ni-CeO2/Al2O3 catalysts with a nickel content of 15 wt% prepared via impregnating boehmite were found to be highly active and stable for methanation of carbon dioxide with hydrogen at a H2/CO2 molar ratio of 4. The effects of CeO2 content and reaction temperature on the performance of the Ni-CeO2/Al2O3 catalysts were studied in detail. The results showed that the catalytic performance was strongly dependent on the CeO2 content in Ni-CeO2/Al2O3 catalysts and that the catalysts with 2 wt% CeO2 had the highest catalytic activity among the tested ones at 350 ℃. The XRD and H2-TPR characterizations revealed that the addition of CeO2 decreased the reduction temperature by altering the interaction between Ni and Al2O3, and improved the reducibility of the catalyst. Preliminary stability test of 120 h on stream over the Ni-2CeO2/Al2O3 catalyst at 350 ℃ revealed that the catalyst was much better than the unpromoted one.

Reduction of TiO_2 with hydrogen cold plasma in DC pulsed glow discharge

The reduction of TiO2 to Ti2O3 with hydrogen cold plasma generated by a DC pulsed glow discharge was realized under 2500Pa at 1233K. Only a little of Ti<sup>10 O<sup>19 and Ti9O<sup>17 was detected for using molecular hydrogen. Enhancement effects of hydrogen cold plasma on the reduction were discussed in terms of thermodynamic coupling, kinetics and plasma sheath. The exited hydrogen species are considered more effective reducing agents. It is instructive to reduce refractory oxides with plasma hydrogen at the reduced temperature.

Effects of magnetic fields on Fe–Si composite electrodeposition

Coatings containing Fe-Si particles were electrodeposited on 3.0wt% Si steel sheets under magnetic fields. The effects of magnetic flux density （MFD）, electrode arrangement and current density on the surface morphology, the silicon content in the coatings and the cathode current efficiency were investigated. When a magnetic field was applied parallel to the current and when the MFD was less than 0.5 T, numerous needle-like structures appeared on the coating surface. With increasing MFD, the needle-like structures weakened and were transformed into dome-shaped structures. Meanwhile, compared to results obtained in the absence of a magnetic field, the silicon content in the coatings significantly increased as the MFD was increased for all of the samples obtained using a vertical electrode system. However, in the case of an aclinic electrode system, the silicon content decreased. Furthermore, the cathode current efficiency was considerably diminished when a magnetic field was applied. A possible mechanism for these phenomena was discussed.

Ionization behavior of deep level donors in passive film formed on surface of stainless steel in 5% salt solution

Deep level donor＇s ionization behavior of passive film formed on the surface of stainless steel was investigated by Mott-Schottky plots. It is indicated that transformation process of deep level donors＇ ionization behavior of passive film on surface of stainless steel can be divided into 4 stages with rising immersion time. At the initial immersion stage （10 min）, Fe（II） located in the octahedral sites of the unit cell is not ionized and the deep level does not appear in Mott-Schottky plots. At the second stage （9-38 h）, Fe（II） located in the octahedral sites starts to be ionized, which results in deep level donors＇ generation and density of deep level donors almost is constant with augmenting immersion time but the thickness of space charge layer is more and more thicker with rising immersion time. At the third stage （48 h-12 d）, density of deep level donors rises with increasing immersion time and the thickness of passive films space charge layer decreases. At last stage （above 23 d）, both the space charge layer＇s thickness and density of deep level donors are no longer changed with increasing immersion time. In the overall immersion stage, the shallow level donors＇ density is invariable all the time. The mechanism of deep level donor＇s ionization can be the generation of metal vacancies, which results in crystal lattice＇s aberration and the aberration energy urges the ionization of Fe（ II ） in octahedral sites.

Experimental Investigation on Viscosity of CaO-MgO(-Al_2O_3)-SiO_2 Slags and Solid-liquid Mixtures

The viscosities for the selected CaO-MgO-SiO2 and CaO-MgO Al2 O3-SiO2 slags were measured by rota- ting cylinder method in a wide temperature range from 1608 K to 1 823 K. The effects of temperature, slag basicity and Al2 O3 content were studied. The results indicated that the viscosity decreased with increasing the slag basicity at the same temperature. And the viscosities of the slag initially increased linearly with increasing Al2 O3 content in the slags and then decreased as the Al2 O3 content in the slags continued to increase. Al2 O3 addition has a more signifi- cant effect on the viscosity than slag basicity in the selected slags. Based on the experimental data and the fraction of solid phases calculated by the thermodynamic software, the effect of solid phases on slag viscosity was evaluated. The results indicated that the relationship between the relative viscosity and the volume fraction of solid phases esti- mated from the slag composition can be reasonable by allowing the inverse maximum fraction of solid particles to vary.

The Droplet Evolution Trend and Purification Efficiency in ESR Process by Superimposing a Static Magnetic Field

The paper investigated the refinement effect on droplet size of Electroslag Remelting(ESR)Process by superimposing a transverse static magnetic field through physical simulation method.A transparent experimental model is built to visualize the ESR process under magnetic field,especially focusing on the formation and departure process of droplets on electrode tip.The results show that due to the interaction between alternating current and external transverse magnetic field,the resulting electromagnetic oscillation in the molten droplet and slag bath refined droplets remarkably, the higher the magnetic field intensity,the smaller the droplet size.However,there exists a suitable frequency of 10Hz for the current which will achieve an optimal effect of droplet's dispersing and refinement.Based on the theory of electromagnetic separation,a new mechanism of removing nonmetallic inclusions in ESR process is proposed.By a simplified circuit model,the inclusion removal efficiency is calculated and it proves that the refinement of droplets under magnetic field could increase the removal efficiency of nonmetallic inclusions in ESR significantly.

Effect of Magnetic Field on Synthesis of Nano-FeOOH by Low-Temperature Neutralization Method

Using XRD,TEM and VSM methods,the phase,morphology and magnetic property of iron hydroxide oxide(FeOOH) which has been prepared by low-temperature neutralization reaction under different magnetic fields were analyzed.It can be found that the magnetic field had a great influence on the product.Acicular goethite(α-FeOOH) was synthetized without magnetic field.When the magnetic flux density was increased to 0.1T,γ-FeOOH was obtained.If the magnetic field intensity was raised to 0.5T,the product was all composed of δ-FeOOH.Moreover,the crystallization of FeOOH was greatly influenced by magnetic field as well.Thermodynamic calculation results show that the magnetic free energy of chemical reaction reached to more than hundreds KJ/mol when the magnetic field is applied.It meaned that the application of magnetic field was conducived to producing the products with higher susceptibility.Even under the low magnetic field,due to the stability of the reaction products was broken by the magnetic field,the magnetic free energy was also effective.

Hydrothermal Synthesis of Nano Ba-Ferrite With Additional High Pressure Under the Magnetic Field

The pressure of hydrothermal system is increased based on the traditional hydrothermal synthesis to prepare nano-barium ferrite at the reaction temperature of 180℃ under different magnetic field.Using XRD,SEM and TEM methods,the phase composition and micro structure of the nano-barium ferrite powder obtained under different initial pressure(l.0atm,1.5atm and 2.0atm) is discussed.All the powder prepared under different initial pressure is mainly composed of BaFe_(12)O_(19).But the morphology of the products is different.Flake BaFe_(12)O_(19)is obtained under the 10T magnetic field when the initial pressure is 1.5atm and 2.0atm.Moreover,the degree of crystallinity of hydrothermal products is also improved by the application of magnetic field and additional high pressure.Hexagonal flake grains of BaFe_(12)_(19) with excellent crystallization have been prepared under 6T magnetic field,when the initial pressure reached 2.0atm,some of the rod-like BaFe_(12)O_(19) self-organized to form ordered forked structure through oriented attachment due to the multiple influence of pressure and magnetic field on crystal face energy.It can be found that the additional high pressure will disturb the influence of the magnetic field on one-dimensional growth.And the phenomenon of oriented attachment can be regarded as the intermediate state between the one-dimensional rod and two-dimensional sheet.

Parametric Instability of a Liquid Metal Sessile Drop Under a High Frequency Amplitude-Modulate Magnetic Field

The parametric instability behavior of a liquid mercury sessile drop under high frequency Amplitude-Modulate Magnetic Field(AMMF),i.e.a high frequency magnetic field(carder wave)modulated by a low frequency sine wave(modulate wave),is investigated experimentally.The free surface contour of the mercury drop is observed by a CCD camera while varying the frequency and amplitude of the high frequency AMMF.At a given frequency and amplitude,the edge deformations with an azimuthal wave numbers(modes n=3,4,5,6)were excited.

Study on Flow in Mold With EMBr in Slab Continuous Casting

A mercury model has been developed to investigate the influences of Electromagnetic Mold Brake Ruler(EMBr-Ruler) and Flow Control Mold(FC Mold) on metal flow in slab continuous casting mold with the practical casting speed 1.0,1.3 and 2.0 m/min respectively.FC-Mold can efficiently repress the surface flow and its fluctuation.The expanding space of the jets is compressed by EMBr-Ruler and FC-Mold respectively,then the 'flow passage' where the vertical velocity of flow increases sharply is developed near the narrow wall with EMBr-Ruler and FC-Mold.It is bad for the development of the plug like flow.Only the nozzle ports are placed in the braking magnetic field region and the casting speed is suitable,EMBr can be beneficial to the formation of the plug like flow.The flow regime is improved with FC Mold when the casting speed is high(2.0 m/min),but EMBr can improve the flow field with medium casting speed(1.3 m/min),but when the casting speed is low(1.0 m/min),the effects of two types of EMBr are both unsatisfactory.