Anomalies in Flash Points of Liquid Mixtures

Gerstein, Melvin; Stine, W.B.

doi:10.1021/i360047a018

Cited by 5 publications

(5 citation statements)

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“…The anomaly observed on the flash points in open cup, an ignition out of the vessel, was also in line with the anomaly described by Gerstein as caused by the mixing with air [11]. As indicated by Gerstein, such ignition occurs in vapor-air conditions that differs from the expectations of standard procedures and may not alter the validity of the test but it exhibits the fact that some liquids presenting no flash point can explode or burn in certain conditions.…”

Section: Resultssupporting

confidence: 86%

“…In 1930, Snell investigated mixtures of carbon tetrachloride (CCl4) with toluene and acetone [10]. In 1973, Gerstein et al performed a qualitative investigation of the flammability of kerosene-CCl4 mixtures but without quantitative determination of the flash point [11]. The most complete flash point profiles available in the literature were proposed by Rybicky et al in 1981 for trichloroethylene, trichloroethane and dichloromethane mixtures with toluene [12].…”

Section: Introductionmentioning

confidence: 99%

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Flash point of binary mixtures of chlorinated hydrocarbons with toluene and their predictability with existing mixing rule

Fayet

Tribouilloy

Rotureau

2019

Process Safety Progress

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The flash points of binary mixtures of toluene with two chlorinated hydrocarbons (trichloroethylene and dichloromethane) at different concentrations were investigated to evaluate their predictability by existing mixing rules.Measurements were performed using both open and closed cup flash point testers highlighting complex ignition phenomena. Beyond a certain level of concentration in chlorinated compound, no proper flash is observed, in our test conditions when the flame is presented, but specific behaviors are observed that did not allow the definitive determination of a flash point. The observed phenomena can be attributed to the formation of halogenated radicals, presenting flame-retardant behaviors, by decomposition of the chlorinated vapors at the contact of the flame.Existing mixing rules are based on the consideration of the vapor-liquid equilibrium defining the amount of flammable vapors above the liquid surface. So, the application of such mixing rule failed predicting this specific phenomenon, more likely related to a specific reactivity problem.This work also confirms that the sole consideration of the flash point to investigate the flammability of such mixtures may lead to an underestimation of their actual hazard. Additional experimental tests should be conducted to investigate deeper the flammability of such liquid mixtures.

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Flash point of binary mixtures of chlorinated hydrocarbons with toluene and their predictability with existing mixing rule

Fayet

Tribouilloy

Rotureau

2019

Process Safety Progress

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“…Although a number of analytical models already exist for wall-stabilised arcs subjected to axial flows (for example Stine andWatson 1962, Koller 1966), these are subject to restrictive assumptions which make them invalid for comparison with the experimental results presented in this paper. For instance Stine and Watson have neglected axial conduction and radial convection losses and therefore assumed an arc with an axially independent radius.…”

Section: Theorymentioning

confidence: 99%

The influence of laminar and turbulent flows upon the electrical characteristics of wall-stabilised arcs

Hill

Jones

1979

J. Phys. D: Appl. Phys.

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Measurements are reported of the electrical properties of wall-stabilised arcs subject to an imposed axial flow of nitrogen under steady current conditions. The current was in the range 10-60 A DC and the gas flow rate was 0-0.6 g s-1 with stabilising bore radii of 2.5 mm and 5 mm. The results of the investigation confirm the existence of two axial zones corresponding to a flow entrainment region and a fully developed column region. The electric field strength along the fully developed region increases with mass flow rate as turbulent effects become more pronounced. An analytical arc model, based upon boundary layer approximations and taking account of molecular and turbulent radial diffusion and axial convection, is presented. Results of calculations using this model predict the trends observed experimentally.

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“…Flash point measurements of various types are used as one measure of the flammability of liquid materials. The flash point is also related to the lower flammability limit, which is the minimum content of the combustible in a combustible–air mixture that will propagate flame [1]. Many manufacturing processes involve flammable chemicals; therefore, flash points and flammability limits are essential to maximize safety in process design and operational procedures.…”

Section: Introductionmentioning

confidence: 99%

A review of estimation methods for flash points and flammability limits

Vidal

Rogers

Holste

et al. 2004

Process Safety Progress

122

100

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INTRODUCTIONFlash point measurements of various types are used as one measure of the flammability of liquid materials. The flash point is also related to the lower flammability limit, which is the minimum content of the combustible in a combustible-air mixture that will propagate flame [1]. Many manufacturing processes involve flammable chemicals; therefore, flash points and flammability limits are essential to maximize safety in process design and operational procedures.Flammability is an important factor in the development of safe practices for handling and storage of liquid mixtures. Regulatory authorities use flash point determinations made from small-scale test apparatus to classify flammable and combustible liquids. These determinations are based mainly on the use of the closed cup flash point temperature as the key property for classifying liquids according to their degree of flammability. Based on these classifications, regulators then specify or provide guidance on the appropriate methods for transporting, handling, packaging, storing, dispensing, and protecting these materials [2]. Also, federal regulations require that the mixture flash point be provided as part of materials safety data information.Industry works with mixtures under different conditions of temperature, pressure, and oxygen concentrations according to the process involved. The flash point can be used to determine the level of risk in different stages of a process because it is the temperature at which sufficient vapor is generated to bring the concentration of flammable vapor above the lower flammability limit. One question that must be answered to ensure a safe level of operation in a certain process is "What is the minimum oxygen concentration requirement for flame propagation?" Or, in terms more directly applicable to process operations, "What is the minimum amount of inerts required to prevent flame propagation?"The quantity of air that is required to decrease the combustible vapor concentration to a safe level in a particular process carried out at a specific temperature should be based on flammability measurements at that temperature.Knowledge of flammable limits at elevated temperatures and pressures is needed for safe and economical operation of some chemical processes. This information may be needed in order to start up a reactor without passing through a flammable range, to operate the reactor safely and economically, or to store or ship the product safely [3].Flash points are available for most pure liquids, but the information for mixtures is very limited and is usually at ambient pressures. For mixtures of flammable liquids, or more importantly, liquid mixtures containing both flammable and nonflammable constituents, the precise level of risk is more difficult to predict. Mixtures of flammable and nonflammable constituents are especially significant because the vapor phase composition differs from the liquid composition, and it can change from nonflammable to flammable as the mixtures evaporates or its temperatures changes....

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Anomalies in Flash Points of Liquid Mixtures

Cited by 5 publications

References 0 publications

Flash point of binary mixtures of chlorinated hydrocarbons with toluene and their predictability with existing mixing rule

Flash point of binary mixtures of chlorinated hydrocarbons with toluene and their predictability with existing mixing rule

The influence of laminar and turbulent flows upon the electrical characteristics of wall-stabilised arcs

A review of estimation methods for flash points and flammability limits

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