Combustion terms

Hence, under some circumstances the heat losses could be neglected compared to Q 10 1 to 1, the combustion term. 

Colorimetry—An analytical method by which the amount of a compound in solution can be determined by measuring the strength of its color by either visual or photometric methods. Combustible— Term used to classify certain liquids that will burn on the basis of flash point NEPA and DOT classify combustible liquids as having a flash point of 100°F (38°C) or higher. Combustible liquids—OSHA defines combustible liquids as any liquid having a flash point at or above 100°E (38°C) but below 200°E (93.3°C). 

Into the chemistry of the reaction must be added a third aspect - the initiation energy required to make the reaction go, which in combustion terms is known as the source of ignition. 

Flameless Combustion. Term sometimes used for surface combustion (q.v.). Flanged Finish. See finish. 

Hazards of fire and explosion. Many employees do not understand the difference between flammables and combustibles. Terms such as flash point and explosive limits are not always taught to those who handle dangerous chemicals. Many warehouses handle and store containers of liquids that contain chemicals with flash points below 100° F. The lower the flash point the more dangerous the chemical is... 

The utility system also creates waste through products of combustion from boilers and furnaces and wastewater from water treatment, boiler blowdown, etc. Utility waste minimization is in general terms a question of ... 

The long-term effects of CECs and HCECs leaking into the environment have been discussed. Combustion where aU ceUular plastics can evolve smoke containing carbon monoxide and in certain cases cyanide and other toxic gases from various constituents involved in thein manufacture is also a consideration. 

Some additional methods of classification are under development that center on the use of lignite for combustion in utihty boilers or electric power generation. Correlations based on the sodium concentration in the lignitic ash (10), or soluble A1 concentration (11) are used. The classifications are often given in terms of the severity of boiler fouling. 

Gas Combustion Retort. The continuous gas combustion retort (GCR) has been modeled after the earlier batch-operation NTU retort. Although the term "gas combustion" has been appHed to this process, it is a misnomer in that, in a weU-designed and properly operated system, the residual char on the retorted shale suppHes much of the fuel for this process. The GCR is the foremnner of most continuous AGR processes (Table 7). 

All phosphoms oxides are obtained by direct oxidation of phosphoms, but only phosphoms(V) oxide is produced commercially. This is in part because of the stabiUty of phosphoms pentoxide and the tendency for the intermediate oxidation states to undergo disproportionation to mixtures. Besides the oxides mentioned above, other lower oxides of phosphoms can be formed but which are poorly understood. These are commonly termed lower oxides of phosphoms (LOOPs) and are mixtures of usually water-insoluble, yeUow-to-orange, and poorly characteri2ed polymers (58). LOOPs are often formed as a disproportionation by-product in a number of reactions, eg, in combustion of phosphoms with an inadequate air supply, in hydrolysis of a phosphoms trihahde with less than a stoichiometric amount of water, and in various reactions of phosphoms haUdes or phosphonic acid. LOOPs appear to have a backbone of phosphoms atoms having —OH, =0, and —H pendent groups and is often represented by an approximate formula, (P OH). LOOPs may either hydroly2e slowly, be pyrophoric, or pyroly2e rapidly and yield diphosphine-contaminated phosphine. LOOP can also decompose explosively in the presence of moisture and air near 150° C. 

The term oil includes a variety of liquid or easily liquefiable, unctuous, combustible substances that are soluble in ether but not in water and that leave a greasy stain on paper and cloth. These substances can include animal, vegetable, and synthetic oils, but usually the word oil refers to a mineral oil produced from petroleum (qv). An oil that has been used or contaminated, or both, but not consumed, can often be recycled to regain a useful material, regardless of its origin. For the purposes of this article, only the recycling of used petroleum oils is considered. 

Combustion. The primary reaction carried out in the gas turbine combustion chamber is oxidation of a fuel to release its heat content at constant pressure. Atomized fuel mixed with enough air to form a close-to-stoichiometric mixture is continuously fed into a primary zone. There its heat of formation is released at flame temperatures deterruined by the pressure. The heat content of the fuel is therefore a primary measure of the attainable efficiency of the overall system in terms of fuel consumed per unit of work output. Table 6 fists the net heat content of a number of typical gas turbine fuels. Net rather than gross heat content is a more significant measure because heat of vaporization of the water formed in combustion cannot be recovered in aircraft exhaust. The most desirable gas turbine fuels for use in aircraft, after hydrogen, are hydrocarbons. Fuels that are liquid at normal atmospheric pressure and temperature are the most practical and widely used aircraft fuels kerosene, with a distillation range from 150 to 300 °C, is the best compromise to combine maximum mass —heat content with other desirable properties. For ground turbines, a wide variety of gaseous and heavy fuels are acceptable. 

Equation 1 is referred to as the selective reaction, equation 2 is called the nonselective reaction, and equation 3 is termed the consecutive reaction and is considered to proceed via isomerization of ethylene oxide to acetaldehyde, which undergoes rapid total combustion under the conditions present in the reactor. Only silver has been found to effect the selective partial oxidation of ethylene to ethylene oxide. The maximum selectivity for this reaction is considered to be 85.7%, based on mechanistic considerations. The best catalysts used in ethylene oxide production achieve 80—84% selectivity at commercially useful ethylene—oxygen conversion levels (68,69). 

The balanced equation for turbulent kinetic energy in a reacting turbulent flow contains the terms that represent production as a result of mean flow shear, which can be influenced by combustion, and the terms that represent mean flow dilations, which can remove turbulent energy as a result of combustion. Some of the discrepancies between turbulent flame propagation speeds might be explained in terms of the balance between these competing effects. 

Combustion chemistry in diffusion flames is not as simple as is assumed in most theoretical models. Evidence obtained by adsorption and emission spectroscopy (37) and by sampling (38) shows that hydrocarbon fuels undergo appreciable pyrolysis in the fuel jet before oxidation occurs. Eurther evidence for the existence of pyrolysis is provided by sampling of diffusion flames (39). In general, the preflame pyrolysis reactions may not be very important in terms of the gross features of the flame, particularly flame height, but they may account for the formation of carbon while the presence of OH radicals may provide a path for NO formation, particularly on the oxidant side of the flame (39). 

The physics and modeling of turbulent flows are affected by combustion through the production of density variations, buoyancy effects, dilation due to heat release, molecular transport, and instabiUty (1,2,3,5,8). Consequently, the conservation equations need to be modified to take these effects into account. This modification is achieved by the use of statistical quantities in the conservation equations. For example, because of the variations and fluctuations in the density that occur in turbulent combustion flows, density weighted mean values, or Favre mean values, are used for velocity components, mass fractions, enthalpy, and temperature. The turbulent diffusion flame can also be treated in terms of a probabiUty distribution function (pdf), the shape of which is assumed to be known a priori (1). 

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