Minimum combustion temperature

Oxidation (combustion) within the oil bearing bed will be stable, if, under the given condition, the temperature at the edge of the burning front is at least equal to the minimum combustion temperature in the bed, otherwise, at h > 2, the temperature in the center of the burning front must be two times higher than the minimal. Then the stability test will be ... 

Ammonium chloride, which is contained in the green mixture, also affects aluminum nitride particle morphology. The influence of ammonium chloride on AIN particle shape and size is well seen at high content of NH4CI (10 mass%) and minimum combustion temperature, that is, at combustion under the conditions close to threshold [34]. In Figure 1.11b, we can see the general view of aluminum nitride powder obtained at F = 4 MPa and = 1890 K. It is obvious that thread-hke crystals exist along with spherical particles. It supports the idea that... 

Using the assumption of a minimum flame temperature needed for ignition of the mixture, determine the minimum fuel mass loss rate per unit surface area (m l) to cause flame propagation through the boundary layer. The heat of combustion that the volatile wood produces (Ahc) is 15 kJ/g. (Hint the adiabatic flame temperature at the lower flammable limit for the mixture in the boundary layer must be at least 1300 °C.)... 

The lower explosive limit and minimum explosive concentrations of flax, wool, cotton, jute, hemp and sisal fibres are of the same order of magnitude as those of highly explosive dusts [15], The explosibility of pyrites dusts with sulfur contents above 20% was evaluated experimentally. Dusts of 30% sulfur content gave explosion pressures of 3 bar at pressure rise rates of 16 bar/sec. Mixtures of 60% pyrites and 40% powdered limestone still showed significant pressure effects, and the proportion of limestone actually needed to suppress explosions was considerably above the values currently accepted by mining industries [16], Effects of mixtures of particle sizes in combustible dusts upon minimum ignition temperature (T ") and upon presence or absence of explosion were studied. Presence of 30% of fines in a coarse dust lowers Tf significantly [17], Experimental explosions of polyethylene,... 

Taffanel held the view that the limit of propagation is caused by the existence of thermal losses and that, as a result, a certain minimum chemical reaction rate is required in order for combustion to occur. He further showed that under certain instrumental conditions, as the initial temperature is raised, increasingly diluted mixtures are capable of burning, and that in all the cases at the limit the combustion temperatures are practically the same. We have no information on the external reasons why Taffanel s work stopped. The internal, fundamental reasons which prevented him from developing an orderly and complete theory of combustion processes lay in the undeveloped... 

Thus, in a stoichiometric mixture of 2CO + 02 with 2% water content, the flame velocity is 90 cm/sec addition of 1.8% CC14 decreases the flame velocity to 40 cm/sec. At the limit, with a 4.5% CC14 content, the minimum velocity is 4 cm/sec, in good agreement with absolute calculations and with the minimum velocities in other carbon monoxide mixtures. Drozdov showed experimentally that any factor which increases the flame velocity (an increase in the carbon monoxide and water vapor content, an increase in the combustion temperature) simultaneously increases the amount of flegmati-zor (tetrachloride carbon) which is necessary to render the mixture incombustible. 

The theoretical combustion temperature is thus only 240° C. The minimum temperature of self-ignition, meanwhile, recorded in experiments by... 

Incompleteness of combustion is maximal at the boundaries of the interval (21) and reaches a minimum inside this interval at the thermal intensity at which the heat transfer lowers the combustion temperature by the quantity RT2/E. 

One thermal balance equation, even if it is correctly constructed, can give only the combustion temperature under given conditions. To find the limit, additional considerations are essential, for example, those establishing the minimum allowable combustion temperature or the dependence of the flame velocity on the combustion temperature, which Holm does not include. 

Fig. V.A. 1 Hydrogen/oxygen combustion products characteristics and propellant performance. The maximum specific impulse lies at a mixture ratio between the mixture ratios of minimum molecular weight and maximum combustion temperature. Pc = 1000 psia, optimum equilibrium expansion to one atmosphere ambient pressure...

Operational criteria (for example, requiring a minimum furnace temperature of 850 °C, or maintenance of a minimum excess oxygen level in the combustion gas). 

Propane gas and air are to be mixed and fed to a combustion reactor. The combustion is to be initiated with a gas torch. Determine the minimum and maximum percentages of propane in the feed to the reactor and the minimum required temperature of the torch flame. 

Combustibility is also influenced by the amount of oil present the minimum reaction temperature (i.e., the minimum temperature required to cause onset of spontaneous combustion) is lowest in the region where the clay is saturated with 50-60% oil and rises (i.e., becomes less pyrophoric) as the oil content is further reduced to 40% and then to 30%. What these data suggest is that spent clay should be stripped of as much oil as possible before the resultant filter cakes are exposed to the atmosphere. The incorporation of ethoxyquin (a well-known antioxidant used to control spontaneous combustion in fish meal) into the clay/oil mass at the 100-ppm level did reduce the tendency to undergo spontaneous combustion however, whether this approach is practical and how it could be accomplished in plant operations is an open question. 

Properties Colorless liquid characteristic odor. D 1.353 (20/4C), bp 119C (0.15 mm Hg), flashp 280F (137.7C) (OC). Miscible with most common organic solvents insoluble in water and hydrolyzes in water. Undergoes intramolecular isomerization at higher temperatures, exposure to air should be minimum. Combustible. 

Its formation can be kept to a minimum by keeping the excess air supplied to combustion units to a minimum value for safe complete combustion [56]. Burner designs that produce a more diffuse flame front (large flame volume) achieve lower peak combustion temperatures, which helps to decrease the formation of nitric oxide. Injection of ammonia into the flue gas while it is still hot can decrease NOx concentrations down to 80-120 ppm, one-third to one-half that of uncontrolled discharges [64]. Measures for NO reduction during operation of fluid catalytic crackers have been evaluated in pilot scale reactors [65]. 

Viscosity/pour point Is a measure of HFO resistance to flow. They have high viscosity (depending on the grade) and often require heating for handling and combustion. The minimum heating temperature is defined by the pour point. The viscosity is not an additive property therefore oil blends have to be determined experimentally. 

To assure minimum bottom temperature difference across the furnace width of the load, two T-sensors should be installed, one on each side of the furnace (arrows 3 and 4 in fig. 3.26). The 4 T-sensors should be positioned 1 to 3 in. (25 to 75 mm) above the pier top in the wall opposite the high-velocity burners, controlling the fuel input (with combustion air flow held constant). The 3 T-sensor should be at the same elevation as the 4 sensor, on the same side as the high-velocity burners. In a heavily loaded furnace at forging temperature, the two opposite lower sensors should be within 6°F (3.3°C) of one another. 

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