Ignition temperature acetylene

Silver acetylide, Ag2C2, is a white powder formed when acetylene is passed through an ammoniacal solution of silver chloride. It has even stronger explosive properties than cuprous acetylide due to its exceptionally large negative heat of formation —87.15 kcal/mole). Its ignition temperature is 200°C. It is of... 

The results for acetylene were not altogether satisfactory, the ignition temperature of a mixture of acetylene and air appeared to be about 390° C. 

Several types of atomization cell are available flame, graphite furnace, hydride generation and cold vapour. Flame is the most common. In the premixed laminar flame, the fuel and oxidant gases are mixed before they enter the burner (the ignition site) in an expansion chamber. The more commonly used flame in FAAS is the air-acetylene flame (temperature, 2500 K), while the nitrous oxide-acetylene flame (temperature, 3150K) is used for refractory elements, e.g. Al. Both are formed in a slot burner positioned in the light path of the HCL (Fig. 27.4). 

Acetylene burns in air with an intensely hot, luminous, and smoky flame. The ignition temperatures of acetylene and of acetylene-air and acetylene-oxygen mixtures vary according to composition, initial pressure, initial temperature, and water vapor content. As a typical example, an air mixture containing 30 percent acetylene by volume at atmospheric pressure can be ignited at about 581 °F (305°C). The flammable limits of acetylene-air and acetylene-oxygen mixtures similarly depend on initial pressure, temperature, and water vapor content. In air at atmospheric pressure, the upper flammable limit is about 80 percent acetylene by volume and the lower limit is 2.5 percent acetylene. Some references list the upper flammable limit as 100 percent, which is due to the de-... 

The glass fiber based catalysts containing transition metals in highly dispersed state (mostly, Pt and Pd) were tested in many catalytic reactions, such as deep oxidation of saturated hydrocarbons [1], SO2 oxidation [3], deNOx [8], selective hydrogenation of acetylene feedstock [2 ] etc. Despite of extremely low content of noble metals the GFCs showed high activity and thermal stability, low ignition temperature. 

Fig. 1. Pressure required for propagation of decomposition flame through commercially pure acetylene free of solvent and water vapor in long horizontal pipes. Gas initially at room temperature ignition by thermal nonshock sources. Curve shows approximate least pressure for propagation (0), detonation,...

The predetonation distance (the distance the decomposition flame travels before it becomes a detonation) depends primarily on the pressure and pipe diameter when acetylene in a long pipe is ignited by a thermal, nonshock source. Figure 2 shows reported experimental data for quiescent, room temperature acetylene in closed, horizontal pipes substantially longer than the predetonation distance (44,46,52,56,58,64,66,67). The predetonation distance may be much less if the gas is in turbulent flow or if the ignition source is a high explosive charge. 

Fig. 2. Predetonation distances (in m) observed in acetylene at various pressures in horizontal pipes of various diameters. Gas quiescent, at room temperature, ignition by thermal nonshock sources (44,46,52,56,58,64,66,67). To convert kPa to atm, divide by 101.3.

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