Gas oxidation

The Ni-base alloy surface is exposed to an oxidizing gas, oxide nuclei form, and a continuous oxide film forms (Ni) (Cr203, etc.)- This oxide film is a protective layer. The metal ions diffuse to the surface of the oxide layer and combine with the molten Na2S04 to destroy the protective layer. Ni2S and Cr2S3 results sulfidation) ... 

A ir gas ratio Sulphur in gas Oxidation gain in seven 6-h test cycles (g/m )... 

In recent years, aqueous solutions of Xe03 have been used to oxidize a species in solution, from which A[H°m can be calculated when AH for the oxidation reaction is combined with AH for other reactions. The noble gas oxide Xe03 is used as an oxidant because of its stability and the fact that the final reaction product is Xe(g), which has a zero enthalpy of formation and is easily removed from the reaction mixture. As an example, O Hare4 has reported AfHcm for UCI4. We will not go through the details of his procedure, but the critical step involved measuring A TH for the reaction... 

Self-Test 12.8B Can chlorine gas oxidize water to oxygen gas under standard conditions in basic solution ... 

Thermal treatment of a material in a gas oxidizing atmosphere is the simplest concept. This can be done in air, air diluted in N2, dry air, or in ultrahigh purity O2. In the laboratory practice, calcination is done in flowthrough beds, aided by fluidization, or in static box furnaces. Important aspects are the bed geometry, the removal of the generated gases, and temperature gradients. 

In order to obtain the optimal performance of CNTs in various applications, high purity CNTs will be required. Purification of CNTs generally refers to the separation of CNTs from other entities, such as carbon nanoparticles, amorphous carbon, residual catalyst, and other unwanted species. A number of purification methods including acid oxidation, gas oxidation, filtration, and chromatography have been developed to date. In many cases, various combinations of these methods are used to obtain high quality CNTs. 

X = Cl, Br, OTeF5) Cations Employing the Noble-Gas Oxidant, XeOTeF5+Sb(OTeF5)6"... 

The third block in Fig. 2.1 shows the various possible sensing modes. The basic operation mode of a micromachined metal-oxide sensor is the measurement of the resistance or impedance [69] of the sensitive layer at constant temperature. A well-known problem of metal-oxide-based sensors is their lack of selectivity. Additional information on the interaction of analyte and sensitive layer may lead to better gas discrimination. Micromachined sensors exhibit a low thermal time constant, which can be used to advantage by applying temperature-modulation techniques. The gas/oxide interaction characteristics and dynamics are observable in the measured sensor resistance. Various temperature modulation methods have been explored. The first method relies on a train of rectangular temperature pulses at variable temperature step heights [70-72]. This method was further developed to find optimized modulation curves [73]. Sinusoidal temperature modulation also has been applied, and the data were evaluated by Fourier transformation [75]. Another idea included the simultaneous measurement of the resistive and calorimetric microhotplate response by additionally monitoring the change in the heater resistance upon gas exposure [74-76]. 

Analytikjena Atomic Absorption Spectrometer equipped with an aluminum hollow cathode lamp was used to measure aluminum concentrations. The wavelength and spectral bandpass were set at 309.3 and 1.2 run, respectively. Gas/Oxidant ratio was 0.553. A digital pH meter model Metrohm was used for pH measurements. 

A fuel processor for PEFC application contains sulfur removal, an ATR-enhanced UOB reformer, advanced shift reactors, a steam generation system, a product gas cooler, a PROX system, a gas compressor, an air compressor, an anode-off gas oxidizer, and a control system. Goal efficiency (LHV H2 consumed by fuel cell/LHV fuel consumed by fuel processor) is 69 to 72%. H2 concentration is presently >50% (dry). 

Although iron corrodes under an immense variety of conditions, there are, basically, only two mechanisms involved, namely electrochemical corrosion and (hot gas) oxidation. 

Step (2). Species placement. In accordance with the procedure, the most reduced species Ga (oxidation number 0) is placed in the lower left-hand corner. There are no other species with a 0 oxidation number, and therefore Ga is to be assumed to extend all across the bottom of the diagram. The other... 

In a study the direct aromatization of natural gas over H-gallosilicate, H-gallo-aluminosilicate (Ga-H-[Al]ZSM-5) and Ga-H-ZSM-5 zeolites were compared.412 Natural gas containing 27.3 wt% C2+ hydrocarbons can be converted over Ga-H-[Al]ZSM-5 to aromatics with very high selectivity ( 90%) at a high conversion (70%) at 600°C. This catalyst was found to be the best choice for aromatization of propane413 and n-hexane.414 This results from the uniform distribution of extraframework Ga-oxide species in the zeolite channel.415... 

If the NO concentration is appreciable, the efficiency of trace gas oxidation (free radical chain length) is high for this species, In remote air masses, very low NO concentrations limit recycling of HO, and the HO oxidation rate approaches the prime HO generation rate, for instance by these reactions ... 

A number of different gas, oxide, and metal reference electrodes have been used in molten cryolite. The A1(III)/A1 couple produced by placing molten aluminum in a sintered corundum or boron nitride tube is the traditional reference electrode [33]. However, a CO2/C electrode has also been used. This electrode consists of a graphite-covered copper tube C02 gas is passed through the tube and allowed to bathe the graphite surface while it is immersed in the melt [32]. 

Analysis of the literature on natural gas oxidation to methanol indicates the following main points ... 

Operating industrial facilities (units), designed for natural gas oxidation to methanol, do not currently meet the demand of national economies in methanol and other chemical products. 

In this connection, one of the significant future ways of solving the problem of methanol production may be the creation of largely new selective techniques of natural gas oxidation with hydrogen peroxide. 

Normally a flux is used to remove oxides from surfaces when brazing or soldering, and a gas-oxide torch also requires the use of a flux. However, if the flame is oxygen-rich, as the flux is boiled or burnt off, the excess oxygen from the torch will oxidize the metal s surface before the solder can wet the surface. In a reducing flame, as the flux is boiled or burnt off, the reducing flame will maintain the pure metal until the solder can flow over and wet the surface. 

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