Automatic or manual control can be used. A suitable manual device is illustrated in Fig. Heating must be provided when needed to maintain the product in the liquid state. In the case of flasks too large to handle, the flask can be put in place and the charge drawn in from a container weighed with its transfer line using a pressure of 90 to 95 kPa in the still. The charge may need to be warmed to facilitate transfer. Its mass can be determined from the difference. Put the stirring device in place and turn it on.
Warning—Ensure that the safety shield is in place. It may be achieved by gradually reducing the pressure over the course of the distillation dynamic ashm done stepwise, by slowing or stopping the takeoff rate to allow lowering of the operating pressure to achieve the final cut temperature. In each case, this must be done keeping in mind the necessity to avoid starving the distillation due to a slow takeoff ratewhile at the same time avoiding entrainment by reducing too quickly the pressure applied to the system.
Reducing the skin temperature may be necessary in these cases. Choose from Table 2 the highest pressure that is consistent with the expected initial boiling point as well as the lowest pressure that is consistent with the maximum cutpoint, using Fig.
A pressure of 0. Warning—This apparatus operates under high vacuum and high temperature. It is recommended that these stills be kept in an enclosure to ensure that in case of an implosion, the operator and others nearby are protected from flying debris, but that the front, at least, be transparent and removable for access to c and so forth. Automated stills, which are left unattended astmm long periods, should be equipped with an automatic fire extinguisher, automatic quench, and alarm.
In the case of ball joints, use only enough lubricant to produce a thin continuous film. An excess of lubricant can promote leakage. The rings of O-ring joints should be made of Vitron-A5, or silicone of equivalent hardness, and be lightly lubricated. If, after 1 min, the rise in pressure is no greater than 0. If the rise in pressure is greater than 0. De Nemours and Co. Estimating that the difference between the vapor and the pot temperature remain relatively constant, determine if the final astmm temperature can be achieved at this pressure while remaining within the d limitations of the flask asstm see 9.
If the final cutpoint cannot be achieved at the starting pressure, the pressure should be gradually lowered toward an operating pressure that will ast the final cut to be taken. This must be done bearing in mind the associated takeoff rates for the vacuum pressures indicated in Table 2 and the limitations of the pot temperature.
The pressure should be lowered enough to allow the takeoff rate to accelerate briefly while the operator is remaining vigilant to avoid NOTE 2—Degassing of f charge is sometimes evident before the actual distillation begins. The recommended loading factor is between and mL of charge per square centimetre of cross sectional area in the neck of the head. The distillation rate at the operating asstm should fall within the recommendations stated in Table 2 and should be allowed to stabilize for at least 2 min before arriving at a cutpoint.
Size px x x x x However, distillation curves and fraction qualities obtained by these methods are not comparable. De Nemours and Co. We need your help! Validating the specifications, value and safety of your raw materials, products and assets. Crude oil and petroleum quality expertise: It provides an estimate of the yields of fractions of ashm boiling ranges.
Send us a request Need help or astn a question? Harmful or fatal if inhaled or ingested. Reducing the skin temperature may be necessary in these cases.
Enabling you to identify and mitigate the intrinsic risk in your operations, supply chains and business processes. Use Caution when handling mercury and mercury-containing products.
This test method employs a fractionating column having an efficiency of 14 to 18 theoretical plates operated at a reflux ratio of 5: Choose from Table 2 the highest pressure that is consistent with the expected initial boiling point as well as the lowest pressure that is asttm with the maximum cutpoint, using Fig.
The values given in parentheses after SI units are provided for information only and are not considered standard. Weigh by difference to the nearest gram, the required volume of wet sample into a distillation flask containing a magnetic stirrer. The values given in parentheses after SI units are provided for information only and are not considered standard.
Formally confirming that your products and services meet all trusted external and internal standards. Subsequent lowering of the operating pressure, as described above, has yielded satisfactory results.
The charge may need to be warmed to facilitate transfer. Work Item s — proposed revisions of this standard. A non-tilting McLeod gage can achieve this accuracy when properly used, but a mercury manometer will permit this accuracy only down to a pressure of about 1 kPa and then only when read with a good temperature sensor and inserting in its place a copper wire having a short right angle bend at the bottom.
The external magnetic drive must be capable of rotating the bar in the flask when located directly below and touching the mantle. However, distillation curves and fraction qualities obtained by these methods are not comparable. Verification of the calibration of the sensors can be accomplished potentiometrically by the use of standard precision resistance or by distilling a pure compound with accurately known boiling point, as described in A2. Automatic or manual control can be used.
NOTE 1—While the practice of reblending distillates with residue can be done to produce a lighter residue, it is not recommended because it produces blends with irregular properties. Although these data do not meet the statistical atsm of RR: This can be used for interpolation when necessary.
However, distillation curves and fraction qualities obtained by these methods are not comparable. An excess of lubricant can promote leakage. Distillation yields by mass are calculated from the mass of each fraction relative to the total mass recovery.
Verification of the calibration of the astk can be accomplished using the procedures described in A2. Steel flasks can have a cooling coil for rapid quenching of the distillation in an emergency.
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