1.1 This test method covers the procedure for the distillation of stabilized crude petroleum (see Note 0) to a final cut temperature of 400C Atmospheric Equivalent Temperature (AET). This test method employs a fractionating column having an efficiency of 14 to 18 theoretical plates operated at a reflux ratio of 5:1. Performance criteria for the necessary equipment is specified. Some typical examples of acceptable apparatus are presented in schematic form. This test method offers a compromise between efficiency and time in order to facilitate the comparison of distillation data between laboratories.
Note 0
Defined as having a Reid vapor pressure less than 82.7 kPa (12 psi).
1.2 This test method details procedures for the production of a liquefied gas, distillate fractions, and residuum of standardized quality on which analytical data can be obtained, and the determination of yields of the above fractions by both mass and volume. From the preceding information, a graph of temperature versus mass % distilled can be produced. This distillation curve corresponds to a laboratory technique, which is defined at 15/5 (15 theoretical plate column, 5:1 reflux ratio) or TBP (true boiling point).
1.3 This test method can also be applied to any petroleum mixture except liquefied petroleum gases, very light naphthas, and fractions having initial boiling points above 400C.
1.4 This test method contains the following annexes and appendixes:
1.4.1 Test Method for the Determination of the Efficiency of a Distillation Column,
1.4.2 Test Method for the Determination of the Dynamic Holdup of a Distillation Column,
1.4.3 Test Method for the Determination of the Heat Loss in a Distillation Column (Static Conditions),
1.4.4 Test Method for the Verification of Temperature Sensor Location,
1.4.5 Test Method for Determination of the Temperature Response Time,
1.4.6 Practice for the Calibration of Sensors,
1.4.7 Test Method for the Verification of Reflux Dividing Valves,
1.4.8 Practice for Conversion of Observed Vapor Temperature to Atmospheric Equivalent Temperature (AET),
1.4.9 Test Method for Dehydration of a Sample of Wet Crude Oil, and
1.4.10 Practice for Performance Check.
1.5 &si-value;
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section .
1.6 This test method is for determining the efficiency of a distillation column, under total reflux conditions using the test mixture n-heptane/methylcyclohexane at atmospheric pressure.
1.7 The efficiency is not measured under vacuum conditions because there is no satisfactory test mixture that has a constant relative volatility with pressure.
1.8 This test method is for determining the dynamic holdup of a distillation column using a test mixture of stearic acid in n-heptane.
1.9 This test method is for determining the heat loss of a distillation column under static conditions when a temperature differential exists between the inner and outer walls of a distillation column.
1.10 This test method is for determining whether the temperature sensor is in the proper position for optimum performance.
1.11 This test method is for the determination of temperature response time based upon the rate of cooling of the sensor under prescribed conditions.
1.12 This test method is for determining whether a liquid reflux dividing valve produces the prescribed reflux ratio.
1.13 This practice is for conversion of the actual distillation temperature obtained at sub-ambient pressure to AET corresponding to the equivalent boiling point at atmospheric pressure, 101.3 kPa (760 mm Hg), by means of equations derived by Maxwell and Bonnell.
1.14 This practice is for dehydrating a sample of wet crude oil prior to fractional distillation.
1.15 This practice covers a procedure for calculating column performance from GC boiling point distributions on fractions and residues, obtained by distilling an average (30 to 40 API-gravity) crude oil under actual Test Method D 2892 distillation conditions.
Note 2
There are no theoretical reasons to limit the API-gravity range from 30 to 40. However, the use of a crude oil in the quoted range will, more or less, ensure that sufficient product is available to assess performance, both at the upper and lower end of the temperature scale. The use of heavier crudes may not yield sufficient quantities at the low end, while the reverse is true for lighter crudes.
1.16 The assessment of column performance can be made at any cut point where samples of two adjacent fractions or a residue can be analyzed by gas chromatography. Either fresh or stored samples can be analyzed, as long as they have been protected from loss by evaporation. Recommendations are given for the number and spacing of cut points to be analyzed for performance.
1.17 A precise mathematical method for the calculation of distillation efficiency of multi-component mixtures is described and is recommended. For convenience sake, a simple graphical solution based on the same method is also included.
1.18 Overall column performance is assessed in terms of column efficiency (minimum tray number) and in terms of the differential between the nominal cut point (AET) and the calculated effective cut point (ECP). Criteria are given for acceptance of column performance. Possible corrective action(s), if required, are also indicated.
Product Details
- Published:
- 11/01/2005
- Number of Pages:
- 32
- File Size:
- 1 file , 570 KB
- Redline File Size:
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