Flash point estimate

Liquid Mixtures Flash point temperatures for mixtures of liquids can be estimated if only one component is flammable and the flash point temperature of the flammable component is known. In this case the flash point temperature is estimated by determining the temperature at which the vapor pressure of the flammable component in the mixture is equal to the pure component vapor pressure at its flash point. Estimation of flash point temperatures for mixtures of several flammable components can be done by a similar procedure, but it is recommended that the flash point temperature be measured experimentally. 

Step 4. Solve Eq. (2-120) for temperature. This temperature is the flash point estimate. 

A further approach to estimating flash points of mixed hydrocarbons is to sum volume fraction weighted flashing indexes which are calculated directly from the flash points of the individual components (5). Blend flash points estimated by the latter two methods generally agreed with experimental values within the limits of reproducibility of experimental data. 

Calculating the flash point starting from the mixture s composition is not very accurate however an estimation can be obtained if 7) is determined as-the temperature for which the following relation holds true [ 9 )... 

The flash points obtained experimentally according to the different procedures differ slightly. The present estimation refers to the flash point called the closed cup method. 

The measurement of the vapor pressure and flash point of crude oils enables the light hydrocarbon content to be estimated. 

The method of Shebeko et al. " is the preferred flash point prediction method. The formula of the compound, the system pressure, and vapor pressure data for the compound must be available or estimable. Equation (2-174) is the basic equation. 

The equilibrium vapor pressure of a flammable hquid at its closed-cup flash point about equ s its LFL in percent by volume. Thus, the vapor pressure of toluene at its closed-cup flash point (4.4°C or 40°F) of 1.2 percent (1.2 kPa) is close to its LFL of 1.1 percent. The composite LFL of a mixture may be estimated by Le Cnatelier s Rule ... 

It follows then, that knowing the stoichiometry and having a vapor pressure chart, one can determine the LEL and flash point. Also if either the LEL or flash point is known, a vapor pressure chart can be used to estimate the other. 

Gooding, Charles H., "Estimating Flash Point and Lower... 

The vapor pressure (VP) can be used in conjunction with a measured LEE to estimate flash point. When this is done it is usually found that the calculated flash point is less than the measured value owing to limitations in the flash point test technique (5-1.1.1). Conversely, the LEE can be estimated only approximately from the flash point. The VP can also be used to replace the 10... 

When the reboiler was brought back on line, the water was swept into the heat transfer oil lines and immediately vaporized. This set up a liquid hammer, which burst the surge tank. It was estimated that this required a gauge pressure of 450 psi (30 bar). The top of the vessel was blown off in one piece, and the rest of the vessel was split into 20 pieces. The hot oil formed a cloud of fine mist, which ignited immediately, forming a fireball 35 m in diameter. (Mists can explode at temperatures below the flash point of the bulk liquid see Section 19.5.)... 

T.E.S.T allows you to estimate the value for 96 h fathead minnow LC50, 48 h Daphnia magna LC50, 48 h Tetrahymena pyriformis IGC50, Oral rat LD50, Bioaccumulation factor, Developmental toxicity, Ames mutagenicity, Normal boiling point, Density, Flash point, Thermal conductivity, Viscosity, Surface tension, and Water solubility. 

K. Satyanarayana and P. G. Rao, Improved Equation to Estimate Flash Points of Organic Compounds, Journal of Hazardous Materials (1992), 32 81-85. 

Testing includes screening (e.g., literature research, mixing calorimetiy, thermodynamic calculations, estimation of heats of reaction, DSC, flash point calculations), quantitative assessment (e g., accelerated rate calorimetry, specialized calorimetry), and scaleup (vent size packaging [VSP], modeling, reaction calorimetry). 

Flash point is one of the most important fire safety characteristics and hence it is a very important consideration in solvent design. The flammability limit of a solvent is characterized by its flash point, which is the temperature at which the mixture of air and vapor above the liquid can be ignited (Mullin, 1961). It is the lowest point at which the vapor pressure of a liquid will produce a flammable mixture. The flash point of the solvent can be estimated using the following group contribution method (ICAS, 2003)... 

From the viewpoint of safety, information about the flash point is of most significance at or slightly above the maximum temperatures [30 to 60°C (86 to 140°F)] that may be encountered in storage, transportation, and use of liquid petroleum products, in either closed or open containers. In this temperature range the relative fire and explosion hazard can be estimated from the flash point. For products with flash points below 40°C (104°F), special precautions are necessary for safe handling. Flash points above 60°C (140°F) gradually lose their safety significance until they become indirect measures of some other quality. 

Evaluation of the vapor pressure method with normal alkanes disclosed favorable agreement of estimates and data for small, intermediate and large size molecules. Evaluation with other compound types was not performed. If the lower explosive limit (LEL) used in the calculations is estimated, the estimates for flash point should be considered as rough values. 

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