Temperature correction specific gravity

Group the component in a petroleum fraction, which is possible if the normal boiling temperature and the standard specific gravity are known. This method gives correct results when the chemical structure is simple as in the case of a paraffin or naphthene. 

It is rarely that any greater degree of accuracy than that attained in the above methods is required. If, however, scientific accuracy is necessary in specific gravity determinations, the usual standard of comparison, at whatever temperature the determination may be made, is water at its maximum density temperature, namely 4°. If no correction is made for the weight of the air contained in the bottle or tube, accuracy to the fourth place of decimals is ensured by reducing the observed weighings to vacuum weighings. This can be done by the equation—... 

Tables have been published relating Baume, Brix and specific gravity. As density is temperature dependent it is necessary to either bring the syrup to a fixed temperature or, as is more common in practice, to use temperature correction factors or tables. The relationship between density and concentration is slightly different for invert sugar or glucose syrups. The Brix scale is sometimes applied to products that are not sucrose syrups, such as concentrated fruit juice. Recipes are certainly in use that state boil to x Brix . In practice these instructions mean that the material should give the same reading as a sugar syrup of that concentration. As often happens in confectionery these practices have been proved to work empirically.

The data from the density (specific gravity) test method (ASTM D1298 IP 160) provides a means of identification of a grade of naphtha but is not a guarantee of composition and can only be used to indicate evaluate product composition or quality when used in conjunction with the data from other test methods. Density data are used primarily to convert naphtha volume to a weight basis, a requirement in many of the industries concerned. For the necessary temperature corrections and also for volume corrections, the appropriate sections of the petroleum measurement tables (ASTM D1250 IP 200) are used. 

Support Protocol Density measurement The required time depends strongly on the equipment being used. Modern analytical equipment can correctly measure density within minutes. If the density measurement is conducted using the specific gravity bottle method, then an initial calibration is required that can take up to several hours (due to the fact that the volume of the bottle has to be determined as a function of temperature). After the initial calibration curve has been obtained, tests can be conducted within 15 to 20 min since only a precise mass determination is necessary. 

When the specific gravity is determined at a temperature other titan 15, the necessary corrections are obtained from tables given by G. Tommasi (Ann. R. star, chtm. agr. spertrn. di Roma, 1913, VI, p. 157). 

Absolute Specific Gravity (Abs sp gr, sp gr, d j or S) can be defined as the ratio of true weight of a substance (wt corrected to air buoyancy) to true wt of water contained in the same volume at the same temperature. For gases, the term sp gr refers to dry air at the same pressure temp. In US industries, the term "specific gravity", without the prefix "absolure" may refer to wts not corrected to the effects of air buoyancy (apparent wts). The sp grs using the uncorrected wts are known in science as Apparent Specific Gravities and they do not differ more than 0.1% from the sbsolute values (See also Ref 2, p 411 Ref 13, p 876... 

Many references give the specific gravity of gases with reference to air. For example, the specific gravity of carbon dioxide is 1.52 relative to air at the same temperature and pressure. Show that this value is correct as long as the ideal gas equation of state applies. 

A bellow style pressure relief valve is required to protect a vessel containing an organic liquid. The required relieving capacity is 310 gpm. Inlet temperature is 170°F. Set pressure is 100 psig. Allowable overpressure is 25%. Built-up back pressure is 25 psig. Specific gravity is 1.45 and viscosity is 3,200 cP, Determine the orifice size of the valve. The correction factors are ... 

States and England the specific gravity, unless when otherwise express, is always taken at (jO F. but in Franco at 32, or temperature of melting ice. In most coses, however, it is sufficient merely to note the temperature, and to apply a correction, depending on the known density of water or air, at e different dc es of tho thermometric a o. 

The second method of measuring energy flow using independent measurements of volumetric flow was provided by a Lone Star Gas orifice meter. Input to the Elliot flow computer included the pressure differential across the orifice plate and the pressure and temperature of the gas at the orifice. A conunercial GB-2000 instrument from Precision Measurement Incorporated provided a continuous input of specific gravity to the flow computer. Calorific value also was provided by the GB-2000. The flow computer used these inputs to calculate the volumetric flow at standard conditions. It then corrected for... 

This is particularly important if the quality of the reflux is estimated by an in-line specific gravity (i.e. density corrected for temperature) instru-... 

When carrying out a batch distillation on a binary mixture it is very useful to have a quick and user-friendly analysis of the overheads. It is even better if the analysis can be performed on the plant without the need to take a sample to the laboratory and the process operator has a continuous record of the progress of the batch. A record of this sort can be provided by an on-line specific gravity (i.e. density corrected for temperature) meter. Many binary pairs such as mixtures of methanol, acetone and THF with water have large density differences between the organic distillate and water. This property can be used to control the split between reflux and product flow rates. 

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