Flammability limits theory

Law C.K. and Egolfopoulos F.N., A unified chain-thermal theory of fundamental flammability limits, Proc. Combust. Inst., 24 137-144,1992. 

Spalding, D.B., A theory of flammability limits and flame quenching, Proc. Roy. Soc., A240 83,1957. 

Rapid flame spread. As we know, radiant preheating of a material can cause its surface temperature to approach its piloted ignition temperature. This causes a singularity in simple flame spread theory that physically means that a premixed mixture at its lower flammability limit occurs ahead of the surface flame. Hence, a rapid spread results in the order of 1 m/s. 

The remaining two reviews treat active topics in applied chemical kinetics. Wehner provides a unified treatment of the theory of flames, including the role of intermediates and the problems of flammability limits and ignition conditions. Sinfelt discusses the near-simultaneous conduct of successive reactions needed, for instance, in the reforming of petroleum fractions, as produced by intimate mixtures of metallic and acidic catalysts. 

In considering the application of the gas theory, it is necessary to discuss the limits of flammability of the flammable gases -- that is, the concentrations beyond which the gas is either too diluted or too concentrated to burn, as well as the effect of a nonflammable diluent on these limits. The flammable limits of some of the gases produced burning the thermal decomposition of cellulose are shown in Table 1(6). 

Hertzberg, M. The Theory of Flammability Limits, United States Department of the Interior, Bureau of Mines, Pittsburgh Mining and Safety Research Center, 1976... 

Rates of chemical reactions always have a bearing on ignition, extinction, and flammability limits. There are many situations in which analyses of these phenomena reasonably may employ one-step, Arrhenius approximations to the rates. This fact enables common theories to be developed on the basis of energy considerations, which serve to correlate a number of different observed characteristics of ignition, quenching, and flammability limits. We shall focus our attention here on results explained by energy-conservation requirements and heat losses. In so doing, we exclude the consideration of special effects associated with finer details of chemical kinetics, such as radical diffusion or surface reactions. 

Chapter 9 represents an effort to provide a unified and tutorial presentation of the broad field of the theory of combustion instabilities. The length of the chapter attests to the vastness of the field and to the progress that has been made therein in recent years. The final section of this chapter, on the theory of instabilities of premixed flames, is basic to analyses of premixed turbulent flame propagation and also has a bearing on aspects of flammability limits. 

A theory of diffusion flame propagation under isothermal conditions has been proposed [145]. It has been found that in a simple case the reaction kinetics corresponds to second-order autocatalysis accompanied by first order-consumption of active species. Recently, the burning rate and the flammability limits of a cool carbon suHide flame have been computed [14] making use of the mechanism and rate constants given in a review [233, 234]. The ideas stated in this review apparently provide an explanation for the experimental facts observed the shift of... 

Ethylene (Ethene or Elayl), H2C CH2 mw 28.05 colorless, flammable, dangerous to handle gas with characteristic sweet odor and taste sp gr 0.975 (air = 1.0), mp —169.4°, bp —103.8°, flash p —136°C explosive limits in air, % by vol, lower 3.0 upper 34.0 si sol in w, more in ale sol in eth. Ethylene is a major component of petroleum refinery gas from cracking units, and is sometimes recovered therefrom by distillation or other means. Some pure ethylene is produced by passing hot ethanol vapors over a catalyst, such as activated alumina (Ref 4). Its laboratory prepn consists of heating ethanol in definite proportions with sulfuric acid of certain concns. By using a 90% acid and 90% ale, ethylene can be produced in a regular stream at a yield of 84 to 85% of theory (Ref 2). 

Lysergic acid methylpropylamide Lethal dose-50 The dose of a drug that kills half of the test population Like dissolves like Linear dynamic range Lower explosive limit same as LEL, lower flammability range Lower flammability range Ligand field theory Liquid/liquid extraction such as performed in a separatory funnel or Soxh-let extraction unit Limit of detection... 

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