Efficient reduction of formic acid to formaldehyde by zinc

2019 ◽  
Vol 97 (1) ◽  
pp. 42-45 ◽  
Author(s):  
Nicholas P. Alderman ◽  
Virginie Peneau ◽  
Camilo J. Viasus ◽  
Ilia Korobkov ◽  
Balamurugan Vidjayacoumar ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Formic Acid ◽  
Gas Flow ◽  
Methyl Formate ◽  
Metallic Zinc ◽  
Secondary Products ◽  
Flow Temperature ◽  
Low Concentrations ◽  
Efficient Reduction ◽  
Carrier Gas Flow

The possibility of thermally reducing formic acid to formaldehyde selectively has been probed using metallic zinc. Good selectivity (over 80%) was obtained with low concentrations of formic acid, with methanol and methyl formate as secondary products. The selectivity can be tuned by changing the carrier gas flow, temperature, and zinc amount. Zinc was oxidized to zinc oxide during this process.

scholarly journals Elongated Wire-Like Zinc Oxide Nanostructures Synthesized from Metallic Zinc

2012 ◽  
Vol 15 (1) ◽  
pp. 19 ◽  
Author(s):  
El-Shazly M. Duraia ◽  
G.W. Beall ◽  
Zulkhair A. Mansurov ◽  
Tatyana A. Shabanova ◽  
Ahmed E. Hannora
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Silicon Substrate ◽  
Gas Flow ◽  
Flow Direction ◽  
Crystal Defects ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Metallic Zinc ◽  
Zinc Oxide Nanostructures

Elongated wire-like Zinc oxide, nanocombs and nanocrystals have been successfully synthesized on the silicon substrate from the metallic zinc as a starting material. The annealing temperature was as low as 450 ºC in argon atmosphere mixed with about 3% oxygen. Structural analysis using the X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) showed that the existence of two phases; nanowires and crystalline form. Moreover some nanoparticles aggregates were noticed to be attached in the bulk to the sides of the ZnO nanocrystals and sometimes these aggregate attached to the Zinc oxide hexagonal crystal and grow to form nanowire at different angles. Scanning electron microscopy (SEM) investigations for the zinc oxide nanostructure on the silicon substrate showed the formation of the nanocrystals in the gas flow direction and at the low energy sites over the silicon substrate. Photoluminescence (PL) measurements, performed at the room temperature, showed the existence of two basic emissions: narrow ultraviolet (UV) emission at 398 nm which attributed to the near band edge emission of the wide band gap and a very wide, more intensive, green emission at 471 nm corresponds to the crystal defects such as vacancies, interstitial sites in ZnO.

Fabrication and Ultraviolet Detection Properties of Zinc Oxide by Oxidizing Metallic Zinc at High Temperature

2012 ◽  
Vol 502 ◽  
pp. 258-263
Author(s):  
Shi Guang Shang ◽  
Ke Wei Xu ◽  
Ling Zhao ◽  
Feng Tao He
Keyword(s):  
Zinc Oxide ◽  
High Temperature ◽  
Gas Flow ◽  
Uv Light ◽  
Ambient Pressure ◽  
Hexagonal Wurtzite Structure ◽  
Light Sources ◽  
Metallic Zinc ◽  
X Ray Diffraction ◽  
Interdigital Electrodes

Zinc oxide (ZnO) nanocrystalline with different morphologies, used in ultraviolet (UV) light detection, was successfully fabricated by directly oxidizing metallic zinc at high temperature. X-ray diffraction spectra show that the as-prepared samples are hexagonal wurtzite structure. Scanning electron microscopy images indicate that ZnO with different morphologies such as comb-like, tetrapod and bullet structures could be controlled by simply variables like gas flow rate, ambient pressure and growth temperature. The Photoluminescence (PL) spectra were employed to reveal native point defects in ZnO nanocrystalline. The UV detection properties of ZnO nanocrystalline films screen-printed on interdigital electrodes were investigated by observing the changes of capacitance and conductance under different light sources. The results indicate that the comb-like ZnO nanocrystalline has high UV sensitivity.

scholarly journals On factors affecting surface free energy of carbon black for reinforcing rubber

2020 ◽  
Vol 9 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Shangyong Zhang ◽  
Ruipeng Zhong ◽  
Ruoyu Hong ◽  
David Hui
Keyword(s):  
Free Energy ◽  
Carbon Black ◽  
Surface Free Energy ◽  
Surface Activity ◽  
Gas Flow ◽  
Influential Factors ◽  
Chromatographic Column ◽  
Factors Affecting ◽  
Carrier Gas Flow

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.

Combined Effects of Overheating and Soot-Blower Erosion on Reheater Tubing in a Gas-Fired Large Capacity Boiler

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Nasr M. Hosny
Keyword(s):  
Data Analysis ◽  
Oxide Layer ◽  
Test Data ◽  
Gas Flow ◽  
Combined Effects ◽  
Unit Operation ◽  
Metal Oxidation ◽  
Flow Temperature ◽  
Large Capacity ◽  
Short Time

In a large capacity tangentially fired boiler, the final reheater tubing sustained abnormal oxidation and localized excessive metal wastage in a short time of the unit operation. The root causes of the problem are identified by test data analysis. The test data indicated that the reheater tubing metal temperatures in the affected areas exceeded the recommended limit of the metal oxidation temperature due to higher than expected local gas temperatures and velocities. A soot-blower facing the overheated portion of the reheater leading tubes accelerated the process of metal wastage by periodically removing the oxide layer. The configuration of the boiler internals upstream of the reheater section is found to be the main cause of the localized overheating. Side-to-side gas flow/temperature stratification due to tangential firing contributed to a lesser degree to the problem. The results and conclusions presented in this paper should be a beneficial guide to the designer of large capacity boilers.

Influence of the Variation of Plasma Torch Parameters on Particle Melting and Solidification

1997 ◽  
Author(s):  
M. Vardelle ◽  
P. Fauchais ◽  
A. Vardelle ◽  
A.C. Léger
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Gas Flow ◽  
Operating Conditions ◽  
Characteristic Parameters ◽  
Powder Mass ◽  
Arc Current ◽  
Plasma Sprayed ◽  
Carrier Gas Flow ◽  
Melting And Solidification

Abstract A study of the flattening and cooling of particles plasma-sprayed on a substrate is presented. The characteristic parameters of the splats are linked to the parameters of the impacting particles by using an experimental device consisting of a phase Doppler particle analyzer and a high-speed pyrometer. However, during the long experiments required to get reliable correlations, it was observed that variations in plasma spray operating conditions may alter the particles behavior in the plasma jet. Therefore, a simple and easy-to-use system was developed to control in real time the spray jet. In this paper, the effect of carrier gas flow rate, arc current and powder mass flow rate is investigated. The results on zirconia and alumina powders show the capability of the technique to sense the particle spray position and width.

scholarly journals Artificial Neural Network-based detection of gas hydrate formation

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 117
Author(s):  
Ildikó Bölkény
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Gas Hydrate ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Gas Well ◽  
Low Concentrations ◽  
Gas Hydrate Formation ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

In the production process of natural gas one of the major problems is the formation of hydrate crystals creating hydrate plugs in the pipeline. The hydrate plugs increase production losses, because the removal of the plugs is a high cost, time consuming procedure. One of the solutions used to prevent hydrate formation is the injection of modern compositions to the gas flow, helping to dehydrate the gas. Dehydratation obviously means that the size of hydrate crystals does not increase. The substances used in low concentrations, have to be locally injected at the gas well sites. Inhibitor dosing depends on the amount of gas hydrate present. In the article two Artificial Neural Network (ANN)-based predictive detection solutions are presented. In both cases the goal is to predict hydrate formation. Data used come from two solutions. In the first one measurements were performed by a self-developed and -produced equipment in this case, differential pressure was used as input. In the second solution data are used from the measurement system of a motorised chemical-injector device, in this case pressure, temperature, quantity and type of inhibitor were used as inputs. Both systems are presented in the article.

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