Vacuum temperature correction

Temperature correction factor, vacuum flow. Figure 2-43... 

Process control Proper processing conditions (dosage of processing aids, temperature, pressure/vacuum, flow rate, etc.) must be closely adhered to and monitored to ensure the oil is processed correctly and to minimize undesirable side reactions. In order to assess process efficiency, the oil losses through spent clay or soapstock (as in the case of alkaline refining only) must also be monitored. 

The barometer is an 800-mm or longer tube which is sealed at the upper end, filled with mercury (Fig. 3-la), and inserted into a pool of mercury. If it has been filled in such a way as to avoid having air trapped in the upper end (e.g., by distilling in the mercury under a good vacuum), the height of the mercury column above the pool gives the atmospheric pressure. A temperature correction is usually applied, so that the readings correspond to that of a mercury column at 0°C. The open-end manometer (Fig. 3-1/ ) is closely related to the... 

We ignore any temperature corrections to convert the mercury density and also ignore the gas density above the manometer fluid. Then, since the vacuum reading on the tank is 64.5 cm Hg below atmospheric, the absolute pressure in the tank is... 

The protective film is automatically unrolled from an overhead source using a vertical traversing frame with pinchers that pulls an appropriate length of film over the frame and cuts it to length. The frame is positioned over the edge of the mould. Another bank of heaters slides laterally in front of the mould and warms the film to the correct forming temperature a vacuum is applied at the end of the heating phase to conform the film to the mould. 

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—... 

Measurements of the true specific heats at low temperatures have been carried out by Eucken, who worked in such a way that to a weighed quantity of the substance in the form of a block, or in a proper isolated vessel, a known quantity of heat was added by means of an electrically heated platinum spiral, the resistance of wThich at the same time served to measure the temperature. The quotient of the electrical energy spent by the rise of temperature gives the specific heat. The correction for cooling (in vacuum of 5 Jo mm.) amounted to 20 per cent., and for heat capacity of the apparatus 5 per cent., yet the results are stated to be accurate to 1 per cent. 

Two heat-sensitive organic liquids of an average molecular mass of 155 kg/kmol are to be separated by vacuum distillation in a 100 mm diameter column packed with 6 mm stoneware Raschig rings. The number of theoretical plates required is 16 and it has been found that the HETP is 150 mm. If the product rate is 5 g/s at a reflux ratio of 8, calculate the pressure in the condenser so that the temperature in the still does not exceed 395 K (equivalent to a pressure of 8 kN/m2). It may be assumed that a = 800 m2/m3, /x = 0.02 mN s/m2, e = 0.72 and that the temperature changes and the correction for liquid flow may be neglected. 

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