Increase In Feed Ratio Research Articles

Catalytic Oxidation of Lean Methane over Ni/MgAl2O4 Synthesized by a Novel and Facile Mechanochemical Preparation Method

ABSTRACT In this artcile, methane catalytic oxidation was studied over the Ni/MgAl2O4 catalysts with different weight percentages of nickel oxide synthesized by a simple solid-state mechanochemical preparation method. The Mesoporous nanocrystalline Ni/MgAl2O4 catalysts with high specific surface area displayed high catalytic activity in methane catalytic oxidation. The obtained results demonstrated that the increment in Ni loading improved the CH4 conversion and CO2 selectivity. The influence of O2:CH4 molar ratio and gas hourly space velocity (GHSV) was investigated and the obtained results indicated that the increase in feed ratio and GHSV enhanced the CH4 conversion. Moreover, the incarease in calcination temperature from 500 to 700°C had a negative influence on the catalytic activity because of the formation of agglomerated particles on the calcined catalysts at higher temperatures.

Influence of Steel Strip-Feeding Process on Density and Segregation of Casting Ingot

The effect of steel strip-feeding ratio and superheat degree of molten steel on density and segregation of casting ingot is investigated by an original position analysis. It indicates that under the same degree of superheat condition, with the increase of feeding ratio, the average density of the casting ingot increases and the central segregation of the ingot decreases. Under the same feeding ratio conditions, the density and the central segregation increase with the increase of the degree of superheat.

Effect of Steel Strip-Feeding Process on Solidification Structure

It is investigated that effect of steel strip-feeding ratio and superheat degree of molten steel on solidification structure of ingot by the steel strip-feeding experiment in the mold. The results show that: at the same superheat, with the increase of feeding ratio, the area proportion of equiaxed grain zone increases and the average size of equiaxed grain decreases, and at the same feeding ratio, the higher the superheat is, the smaller the proportion of equiaxed grain zone is, and the larger the average grain size is.

Structural and electrochemical study of polypyrrole/ZnO nanocomposites coating on nickel sheet synthesized by electrochemical method

Polypyrrole/ZnO (PPy/ZnO) nanocomposites coating with different feeding ratios of ZnO (0–30wt%) were prepared on nickel sheet using oxalic acid and dodecylebenzensulfonic acid (DBSA) as electrolyte by electrochemical methods. It was found that surface morphology of PPy coatings showed typical cauliflower-like structure and ZnO nanoparticles were randomly distributed among these structures. Several elements were detected including C, O, S and Zn in PPy/ZnO nanocomposites coating, and the content of ZnO gradually increased with the increase of feeding ratio of ZnO. A peak in XRD patterns was observed around 2θ of 18.8° related to PPy structure, and the peaks at 1544cm−1 and 579cm−1 in FTIR spectra were assigned to stretching vibration of NH bond and ZnO bond, respectively. It was also found that the PPy/ZnO nanocomposites coating had better conductivity and charge storage capability than those of pure PPy. Besides, the corrosion current value of PPy/ZnO nanocomposites coating showed a better corrosion protection.

Study of performance of CeO2/ZnO nanocatalysts for the oxidative coupling of methane using carbon dioxide as oxidant

This study shows how CeO2/ZnO nanocatalysts were prepared by combining homogeneous precipitation with micro emulsion using a conventional heating technique. The catalysts were then used in a conventional fixed bed reactor for the oxidative coupling of methane using carbon dioxide as an oxidant. Catalyst performance tests were carried out at atmospheric pressure, feed gas of 33 and 45 ml/min, and reaction temperatures was in the range of 700 to 900°C. The effect of adding promoters such as Lithium (Li), Bismuth (Bi), and Zirconium (Zr) in various loadings was studied. In this regard, it was found that proper calcination conditions can yield a nanocatalyst structure. However, the conditions for the occurrence of a nanostructure depend strongly on the type of the added promoter. The effects of the number of operating parameters were studied. Catalysts prepared with Zr were found to be more active and selective to ethylene at high calcination temperatures. Catalysts prepared with Bi, on the other hand, showed better activity at lower reaction temperatures. As with Li, the catalysts showed nearly the same activity at low calcination temperatures. As to the effect of feed ratio of methane to carbon dioxide, catalysts prepared with Li showed good activity and selectivity with the increase in the feed ratio. In opposite, catalysts prepared with Zr showed better activity and selectivity at low feed ratios. As to Bi, the increase in feed ratio has an effect on the catalyst activity but not on the selectivity. The study of the effect of different loading of Zr showed that optimal loadings have to be below 5% in weight. Key words: Oxidative coupling of methane, carbon dioxide, CeO2/ZnO catalyst, homogeneous precipitation, micro emulsion.

Effects of feeding ratio on flange bending in shear spinning

The effects of feeding ratio on flange bending of shear spinning are investigated with analytical method. Firstly, influence of feeding ratio on total energy is analyzed utilizing the formula of shear spinning force and power derived by energy method. Subsequently, the connection between the deviation ratio and the thinning ratio, and the influence of feeding ratio on the thinning ratio are researched. Finally, the conclusions about the deviation ratio and flange bending are adopted to reveal the influential tendency of feeding ratio on flange bending. The results show that the flange bending towards headstock weakens with the increase of feeding ratio, which is verified by the experimental results very well. It indicates that the calculation method in this paper is reasonable.

Novel conducting polyaniline copolymers of aniline and N-phenylglycine

N-phenylglycine was firstly applied to prepare the homopolymer and copolymers with aniline by chemical method using ammonium persulfate as oxidant. The products were characterized by Fourier transform infrared (FT-IR), Ultraviolet–visible (UV–vis) and X-ray diffraction (XRD). The conductivity was measured by two-probe method. The solubility increased while the conductivity and yield decreased with the increase in feed ratio of N-phenylglycine in the system.