Light hydrocarbons oxidative

At present, the most known and widely used kinetic model for light hydrocarbon oxidation and combustion is GRI-Mech (Smith et al.), which has been developed since the 1990s by the Gas Research Institute. The project was aimed at the development of the detailed micro-chemical mechanism that can be used for simulations of natural gas ignition and combustion. Now the model is optimized for two fuels, methane and natural gas. Recommended temperature and pressure ranges are 1,000-2,500 K and 1.3 x 10 3-1 MPa, respectively the fuel-to-oxidant equivalence ratio in premixed compositions is 0.1-5. Although the scheme includes some reactions of C2-C3 hydrocarbons and oxygenates participating in methane (natural gas) combustion, it is not recommended to use GRI-Mech for simulations of their oxidation (combustion) as the main initial fuels, since the model is not optimized for these purposes. 

J.-C. Volta - Site Isolation for Light Hydrocarbons Oxidation,... 

LaCoOs ceramic exhibits interesting electrical, magnetic, and catalytic properties, being used as cathode material for solid oxide fuel cells (SOFCs), catalysts for light hydrocarbon oxidation, and gas detection sensors. For other applications such as oxygen separation from air and for synthetic gas production, dense ceramic membranes with well-defined microstructure are required. 

Acetic acid is produced by methanol car-bonylation, which has become the dominant process, as well as by acetaldehyde oxidation and light hydrocarbon oxidation. When methanol carbonylation was first practiced in... 

Currently, almost all acetic acid produced commercially comes from acetaldehyde oxidation, methanol or methyl acetate carbonylation, or light hydrocarbon Hquid-phase oxidation. Comparatively small amounts are generated by butane Hquid-phase oxidation, direct ethanol oxidation, and synthesis gas. Large amounts of acetic acid are recycled industrially in the production of cellulose acetate, poly(vinyl alcohol), and aspirin and in a broad array of other... 

Tubular Fixed-Bed Reactors. Bundles of downflow reactor tubes filled with catalyst and surrounded by heat-transfer media are tubular fixed-bed reactors. Such reactors are used most notably in steam reforming and phthaUc anhydride manufacture. Steam reforming is the reaction of light hydrocarbons, preferably natural gas or naphthas, with steam over a nickel-supported catalyst to form synthesis gas, which is primarily and CO with some CO2 and CH. Additional conversion to the primary products can be obtained by iron oxide-catalyzed water gas shift reactions, but these are carried out ia large-diameter, fixed-bed reactors rather than ia small-diameter tubes (65). The physical arrangement of a multitubular steam reformer ia a box-shaped furnace has been described (1). 

Steam Reforming Processes. In the steam reforming process, light hydrocarbon feedstocks (qv), such as natural gas, Hquefied petroleum gas, and naphtha, or in some cases heavier distillate oils are purified of sulfur compounds (see Sulfurremoval and recovery). These then react with steam in the presence of a nickel-containing catalyst to produce a mixture of hydrogen, methane, and carbon oxides. Essentially total decomposition of compounds containing more than one carbon atom per molecule is obtained (see Ammonia Hydrogen Petroleum). 

Burning a portion of a combustible reactant with a small additive of air or oxygen. Such oxidative pyrolysis of light hydrocarbons to acetylene is done in a special burner, at 0.001 to 0.01 s reaction time, peak at 1,400°C (2,552°F), followed by rapid quenching with oil or water. 

C. Pliangos, I.V. Yentekakis, V.G. Papadakis, C.G. Vayenas, and X.E. Verykios, Support-induced promotional effects on the activity of automotive exhaust catalysts 1. The case of oxidation of light hydrocarbons, Appl. Catal. B 14, 161-173 (1997). 

Most industrial hydrogen is manufactured by the following hydrocarbon-based oxidative processes steam reforming of light hydrocarbons (e.g., NG and naphtha), POx of heavy oil fractions, and ATR. Each of these technological approaches has numerous modifications depending on the type of feedstock, reactor design, heat input options, by-product treatment,... 

In this chapter a two a selectivity model is proposed that is based on the premise that the total product distribution from an Fe-low-temperature Fischer-Tropsch (LIFT) process is a combination of two separate product spectrums that are produced on two different surfaces of the catalyst. A carbide surface is proposed for the production of hydrocarbons (including n- and iso-paraffins and internal olefins), and an oxide surface is proposed for the production of light hydrocarbons (including n-paraffins, 1-olefins, and oxygenates) and the water-gas shift (WGS) reaction. This model was tested against a number of Fe-catalyzed FT runs with full selectivity data available and with catalyst age up to 1,000 h. In all cases the experimental observations could be justified in terms of the model proposed. 

CL is weak in liquid-phase hydrocarbon oxidation and can be intensified. To increase the CL, activators are added to the oxidized hydrocarbon [17,220,223]. The activator takes an excess of energy from the excited ketone molecule and emits light in high yield ... 

CAR [Combined autothermal reforming] A "reforming process for making "syngas from light hydrocarbons, in which the heat is provided by partial oxidation in a section of the reactor. Developed by Uhde and commercialized at an oil refinery at Strazske, Slovakia, in 1991. 

Atmospheric and vacuum distillation units (Figures 4.3 and 4.4) are closed processes, and exposures are expected to be minimal. Both atmospheric distillation units and vacuum distillation units produce refinery fuel gas streams containing a mixture of light hydrocarbons, hydrogen sulfide, and ammonia. These streams are processed through gas treatment and sulfur recovery units to recover fuel gas and sulfur. Sulfur recovery creates emissions of ammonia, hydrogen sulfide, sulfur oxides, and nitrogen oxides. 

Because SOFCs operate at high temperature, they are capable of internally reforming fuel gases (i.e., CH4 and other light hydrocarbons) without the use of a specific reforming catalyst (i.e., anode itself is sufficient), and this attractive feature of high temperature operation of SOFCs has recently been experimentally verified. Another important aspect of SOFCs is that recycle of CO2 from the spent fuel stream to the inlet oxidant, as required by MCFCs, is not necessary because SOFCs utilize only O2 at the cathode. 

The partial oxidation method is normally used for heavier feedstocks, everything from naphtha to residual fuel, in those places where natural gas or light hydrocarbons (ethane, propane, or butane) are not readily available. 

Synthesis gas generation Process in which light hydrocarbons are partially oxidized over a catalyst at about 875 K with oxygen and the carbon monoxide is shifted with steam to produce CO and H. ... 

Heated or nonheated bed designed to oxidize carbon monoxide and light hydrocarbons (not removed by activated charcoal) to carbon dioxide and water. 

Over the initial period of conversion, it was also observed that only small quantities of light hydrocarbon gases were produced. The liberation of carbon oxides, principally CO2, was more facile. For both subbituminous and bituminous coals, the yields of CO2 realised at 300 C were significant, although much higher for the lower rank coal (8.9). 

Most metals cannot be treated by ATDU technology. Soils may require pretreatment if they contain oversized materials or greater than 30% moisture. The off-gas stream may require additional treatment by activated carbon filtration or thermal oxidization to remove light hydrocarbons. 

Light hydrocarbons consisting of oxygen or other heteroatoms are important intermediates in the chemical industry. Selective hydrocarbon oxidation of alkenes progressed dramatically with the discovery of bismuth molybdate mixed-metal-oxide catalysts because of their high selectivity and activity (>90%). These now form the basis of very important commercial multicomponent catalysts (which may contain mixed metal oxides) for the oxidation of propylene to acrolein and ammoxidation with ammonia to acrylonitrile and to propylene oxide. 

M. Kilpatrick L.L. Baker, Jr, A study of fast reactions in fuel-oxidant systems, FifthSymp Comb, Reinhold, NY, (1955) 26) S.A. Masier et al, Hypergolic ignition of light hydrocarbon fuels with fluorine-oxygen (FLOX) mixtures, ... 

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