Ozone decomposition flame,

Rogg, B., A. Linan, and F. A. Williams. 1986. Deflagration regimes of laminar flames modeled after the ozone decomposition flame. Combustion Flame 65 79-101. 

A most successful application of the approximate theory has been performed for the ozone decomposition flame, where the flame velocity has been estimated over the entire 02-03 composition range in which the flame is propagated (V2). A comparison of the calculated flame velocities and the experimental values is made in Fig. 4. 

A list of substances which have been used or considered to support decomposition flames is shown in Table I. Almost all of these substances have been studied at one time or another to provide fundamental information for the evaluation of the theory of flame propagation. As previously mentioned, the ozone decomposition has proved most useful as the basis of a flame which is amenable to both theoretical and experimental study. The NO decomposition flame provided a situation where a clear-cut prediction was made possible by flame theory (P2). On the basis of a flame calculation it was predicted that a strong preheat would permit the stabilization of this flame at a measurable flame velocity, since it was known that a flame would not propagate into the gas at room temperature. Subsequent experimental work confirmed the prediction by stabilizing a flame with approximately the predicted value. This places a great deal of... 

The development of numerical methods allowed calculation of the structure and propagation velocity of a plane laminar flame for the most complex transformation schemes, encompassing up to seventy elementary chemical events. We note the works of G. Dixon-Lewis with S. M. Islam 5 and with F. Gramarossa,26 which studied mixtures of hydrogen with air, methane with air, and flame in ozone decomposition. 

The second is concerned with the need to have a complete and sensible chemical mechanism, valid over a wide range of temperature. Even a relatively simple combustion system will involve dozens of reactions, so that a well established reaction rate data base is essential. It is equivalently essential that the results be verified by comparison with detailed experimental data--such as that provided by laser probes. For example, in a study of the ozone decomposition flame (20). it was found that certain alternative but wrong choices of key input parameters were not discernible if flame speed were used as the sole predicted result for verification however, these choices did produce considerable differences in the profiles of the transient oxygen atom concentration and the temperature. 

An important advance was the introduction of chemical kinetics into the flame propagation theory as illustrated by the explosive ozone decomposition (Lewis and Elbe [272]). Formulating the mechanism... 

The second approach, applied by Margolis (1978) and by Heimerl and Coffee (1980) to ozone decomposition flames, employs a method-of-lines technique. In combination with finite-element collocation methods this technique provides a general approach to the numerical solution of partial differential equations. Taking Eqs. (4.12) and (4.13) as the working examples... 

In terms of B-spline representation, finite-diflerence procedures, corresponding to piecewise linear approximations, have k = 2, with discontinuous first derivatives at the single knots. This was the order of approximation used by Bledjian (1973) for the spatial discretization associated with his early method-of-lines solution for the properties of an ozone decomposition flame. Bledjian s procedure involved a straightforward finite-difference representation of the spatial second derivatives which arise on the right-hand sides of equations of the type of Eqs. (4.12) and (4.13) when the expressions for the transport fluxes j and -h are inserted. His integration of the ordinary... 

As the reaction temperature is increased, chemiluminescence is observed in the reactions of ozone with aromatic hydrocarbons and even alkanes. Variation of temperature has been used to control the selectivity in a gas chromatography (GC) detector [35], At room temperature, only olefins are detected at a temperature of 150°C, aromatic compounds begin to exhibit a chemiluminescent response and at 250°C alkanes respond, giving the detector a nearly universal response similar to a flame ionization detector (FID). The mechanisms of these reactions are complex and unknown. However, it seems likely that oxygen atoms produced in the thermal decomposition of ozone may play a significant role, as may surface reactions with 03 and O atoms. 

CA 50, 12482 (1956) (Flame propagation in ozone) 29)Sax (1957), 161-61 (Destruction of expls) 30)F.C.Ikle, "The Social Impact of Bomb Destruction , Univ of Oklahoma Press, Norman, Okla (1958) 3l)Anon, Ordnance Service in the Field , US Army Field Manual FM 9-1 (1959) (Destruction of ammo) 32)Anon, Ordnance Ammunition Service , FM 9 5 (1959) (Destruction of ammo) 33)A.B.Amster, "Relationship Between Decomposition Kinetics and Sensitivity (U), Stanford Research Institute, Menlo Park, California,Repts (1962), Contract No Nonr 3760(00) (Conf, not used as a source of info) 34)P.W.M.Jacobs A.R.T.Kureishy, Kinetics of Thermal and Photochemical Decomposition of Some Alkali Metal Azides , Imperial College, London, England, Final Tech Rept (1964) Contract DA-91-591-EUC-2059 34a)Anon, Care, Handling, Preservation and Destruction of Ammunition , TM 9-1300-206 (1961) 35)-Anon, Investigations of the Mech-... 

SAFETY PROFILE Poison by inhalation. Potentially explosive decomposition at 200°C. Flammable when exposed to heat or flame. Explosive reaction with ammonia + heat, chlorine, concentrated nitric acid, ozone. Incompatible with oxidants. The decomposition products are hydrogen and metallic antimony. When heated to decomposition it emits toxic fumes of Sb. Used as a fumigating agent. See also ANTIMONY COMPOUNDS and HYDRIDES. 

The decomposition of ozone has been of great interest to those concerned with combustion, because of the apparent simplicity of the reaction and the fact that there is only one product gas, oxygen. Lewis and von Elbe (13) developed a theory of flame propagation in ozone-oxygen mixtures on the basis of their burning velocity studies. They (13) derived high-temperature specific heat values for oxygen from their explosion data. 

HAZARD RISK Very dangerous fire hazard when exposed to heat or flame moderately explosive in the vapor form when exposed to heat or flame forms explosive peroxides when exposed to air can explode spontaneously reaction with ozone forms dangerous products decomposition emits toxic fumes of hydrogen chlonde, chlonne and phosgene NFPA Code H 4 F4 R2. 

A typical chemiluminescence detector consists of a series-coupled thermal decomposition and ozone reaction chambers. The selective detection of nitrosamines is based on their facile low-temperature (275-300°C) catalytic pyrolysis to release nitric oxide. Thermal decomposition in the presence of oxygen at about 1000°C affords a mechanism for conversion of nitrogen-containing compounds to nitric oxide (catalytic oxidation at lower temperatures is also possible). Decomposition in a hydrogen-diffusion flame or thermal oxidation in a ceramic furnace is used to produce sulfur monoxide from sulfur-containing compounds. 

---