Standard Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column)

SCOPE
1.1 This test method covers the procedure for the distillation of stabilized crude petroleum to a final cut temperature of 400°C 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.
1.2 This test method details procedures for the production of a liquified 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 liquified petroleum gases, very light naphthas, and fractions having initial boiling points above 400°C.
1.4 This test method contains the following Annexes:
1.4.1 Annex A1—Test Method for the Determination of the Efficiency of a Distillation Column,
1.4.2 Annex A2—Test Method for the Determination of the Dynamic Holdup of a Distillation Column,
1.4.3 Annex A3—Test Method for the Determination of the Heat Loss in a Distillation Column (Static Conditions),
1.4.4 Annex A4—Test Method for the Verification of Temperature Sensor Location,
1.4.5 Annex A5—Test Method for Determination of the Temperature Response Time,
1.4.6 Annex A6—Practice for the Calibration of Sensors,
1.4.7 Annex A7—Test Method for the Verification of Reflux Dividing Valves,
1.4.8 Annex A8—Practice for Conversion of Observed Vapor Temperature to Atmospheric Equivalent Temperature (AET),
1.4.9 Appendix X1—Test Method for Dehydration of a Sample of Wet Crude Oil, and
1.4.10 Appendix X2—Practice for Performance Check.
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information only.
1.6 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 precautionary notes, see Section 10.

General Information

Status
Historical
Publication Date
09-Dec-2001
Current Stage
Ref Project

Relations

Buy Standard

Standard
ASTM D2892-99a - Standard Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column)
English language
32 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (Sample)


NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 2892 – 99a An American National Standard
Standard Test Method for
Distillation of Crude Petroleum (15-Theoretical Plate
Column)
This standard is issued under the fixed designation D 2892; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Sample of Wet Crude Oil,
1.4.9 Annex A8—Practice for Conversion of Observed
1.1 This test method covers the procedure for the distillation
Vapor Temperature to Atmospheric Equivalent Temperature
of stabilized crude petroleum to a final cut temperature of
(AET), and
400°C AET (Atmospheric Equivalent Temperature). The test
1.4.10 Annex A9—Practice for Performance Check.
method employs a fractionating column having an efficiency of
1.5 The values stated in SI units are to be regarded as
14 to 18 theoretical plates operated at a reflux ratio of 5:1.
standard. The values given in parentheses are provided for
Performance criteria for the necessary equipment is specified.
information purposes only.
Some typical examples of acceptable apparatus are presented
1.6 This standard does not purport to address all of the
in schematic form. This test method offers a compromise
safety concerns, if any, associated with its use. It is the
between efficiency and time in order to facilitate the compari-
responsibility of the user of this standard to establish appro-
son of distillation data between laboratories.
priate safety and health practices and determine the applica-
1.2 The test method details procedures for the production of
bility of regulatory limitations prior to use. For specific
a liquified gas, distillate fractions, and residuum of standard-
precautionary notes, see Section 9.
ized quality on which analytical data can be obtained, and the
determination of yields of the above fractions by both mass and
2. Referenced Documents
volume. From the above information, a graph of temperature
2.1 ASTM Standards:
versus mass % distilled can be produced. This distillation curve
D 941 Test Method for Density and Relative Density (Spe-
corresponds to a laboratory technique, which is defined at 15/5
cific Gravity) of Liquids by Lipkin Bicapillary Pycnom-
(15 theoretical plate column, 5:1 reflux ratio) or TBP (true
eter
boiling point).
D 1217 Test Method for Density and Relative Density
1.3 This test method can also be applied to any petroleum
(Specific Gravity) of Liquids by Bingham Pycnometer
mixture except liquified petroleum gases, very light naphthas,
D 1298 Test Method for Density, Relative Density (Specific
and fractions having initial boiling points above 400°C.
Gravity), or API Gravity of Crude Petroleum and Liquid
1.4 This test method contains the following Annexes:
Petroleum Products by Hydrometer Method
1.4.1 Annex A1—Test Method for the Determination of the
D 2427 Test Method for Determination of C through C
2 5
Efficiency of a Distillation Column,
Hydrocarbons in Gasolines by Gas Chromatography
1.4.2 Annex A2—Test Method for the Determination of the
D 4006 Test Method for Water in Crude Oil by Distillation
Dynamic Holdup of a Distillation Column,
D 4052 Test Method for Density and Relative Density of
1.4.3 Annex A3—Test Method for the Determination of the
Liquids by Digital Density Meter
Heat Loss in a Distillation Column (Static Conditions),
D 4057 Practice for Manual Sampling of Petroleum and
1.4.4 Annex A4—Test Method for the Verification of Tem-
Petroleum Products
perature Sensor Location,
D 4177 Practice for Automatic Sampling of Petroleum and
1.4.5 Annex A5—Test Method for Determination of the
Petroleum Products
Temperature Response Time,
1.4.6 Annex A6—Practice for the Calibration of Sensors,
3. Terminology
1.4.7 Annex A7—Test Method for the Verification of Reflux
3.1 Definitions:
Dividing Valves,
3.1.1 adiabaticity—the condition in which there is no sig-
1.4.8 Appendix X1—Test Method for Dehydration of a
nificant gain or loss of heat throughout the length of the
column.
This test method is under the jurisdiction of ASTM Committee D-2 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.08 on Volatility.
Current edition approved Nov. 10, 1999. Published January 2000. Originally Discontinued; see 1993 Annual Book of ASTM Standards, Vol 05.01.
published as D 2892 – 70 T. Last previous edition D 2892 – 99. Annual Book of ASTM Standards, Vol 05.01.
2 5
Defined as having a Reid vapor pressure less than 82.7 kPa (12 psi). Annual Book of ASTM Standards, Vol 05.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 2892
3.1.1.1 Discussion—When distilling a mixture of com- normally at the top of the condenser.
pounds as is the case of crude petroleum, there will be a normal 3.1.5 distillation temperature—the temperature of the satu-
increase in reflux ratio down the column. In the case where rated vapor measured in the head just above the fractionating
heat losses occur in the column, the internal reflux is abnor- column.
mally greater than the reflux in the head. The opposite is true 3.1.5.1 Discussion—It is also known as the head tempera-
when the column gains heat, as with an overheated mantle. ture or the vapor temperature.
3.1.2 boilup rate—the quantity of vapor entering the col- 3.1.6 dynamic hold-up—the quantity of liquid held up in the
umn per unit of time. column under normal operating conditions.
3.1.2.1 Discussion—It is expressed in millilitres of liquid 3.1.6.1 Discussion—It is expressed as a percentage of the
per hour for a given column or in millilitres per hour per square packed volume for packed columns so that the data can be
centimetre of cross-sectional area for comparative purposes. In compared. For real plate columns, it is expressed in millilitres
the latter case, it refers to the test mixture of n-heptane and per plate. The data can only be compared with others of the
methylcyclohexane in the efficiency evaluation (see Annex A1) same diameter because of different tray spacing. Data for
and is measured at the bottom of the column. The maximum packed columns cannot be compared with those of real plate
boilup of the n-heptane-methylcyclohexane test mixture is that columns except in absolute units of milliliters per theoretical
which the column can handle under stable conditions without plate (see Table 1). Dynamic hold-up increases with increasing
flooding. In routine adiabatic operation, the boilup rate can be distillation rate up to the flood point and varies from one kind
estimated roughly from the takeoff rate multiplied by the reflux of fractionator to another.
ratio plus one. 3.1.7 flood point—the point at which the velocity of the
3.1.3 debutanization of crude petroleum—the removal of upflowing vapors obstructs the downcoming reflux and the
the light hydrocarbons up to and including n-butane, and column suddenly loads with liquid.
retention of the heavier hydrocarbons. 3.1.7.1 Discussion—Under these conditions no vapor can
3.1.3.1 Discussion—In practice, a crude petroleum is re- reach the head and the heat to the distillation flask must be
garded as debutanized if the light hydrocarbon cut collected in reduced to establish normal operations again. The flood point is
the cold trap contains more than 95 % of the C to C normally determined during the efficiency evaluation of a
2 4
hydrocarbons and less than 5 % of the C hydrocarbons column using the n-heptane-methylcyclohexane test mixture
initially present in the sample. (see Annex A1).
3.1.4 distillation pressure—the pressure measured as close 3.1.8 internal reflux—the liquid normally running down
as possible to the point where the vapor temperature is taken, inside the column.
TABLE 1 Data for n-Heptane-Methylcyclohexane Test Mixture at 75 % of Maximum Boilup and 101.3 kPa (760 mm Hg)
A,B,C,D,E F,G,H E,I,J E,K
Propak Helipak Perforated Plates Wire Mesh
Column diameter, mm 25 50 70 25 50 25 50 25 50
L L L L
Packing size, mm 4 6 6 No. 2917 No. 2918 NA NA NA NA
Boilup, mL/h 3 cm 650 670 675 300 350 640 660 810 1050
Dynamic holdup
L L
% of packed volume 17 15.3 17.0 15 14.3 NA NA 8.0 10.0
mL/theoretical plate 3.2 16 39 1.6 8.7 2.8 12.3 2.0 12.9
Pressure drop
L L
kPa/m 1.2 1.05 0.94 1.53 1.41 NA NA 0.97 0.75
L L
mm Hg/m 9.0 7.9 7.1 11.5 10.6 NA NA 7.3 5.6
kPa/theoretical plate 0.045 0.056 0.06 0.03 0.045 0.15 0.16 0.05 0.05
mm Hg/theoretical plate 0.34 0.42 0.43 0.24 0.34 1.1 1.2 0.35 0.37
HETP, mm (% of real plates) 38 53 61 21 32 (60 %) (65 %) 48 66
For 15-plate Towers
Packed height, cm (plates) 57 80 91 31.5 48 (25) (23) 72 99
L L
Packed volume, mL 280 1570 3460 155 917 NA NA 353 1940
Dynamic holdup, mL 47 240 590 23 131 42 184 28 194
Pressure drop
kPa 0.68 0.84 0.86 0.48 0.68 2.2 2.4 0.70 0.73
mm Hg 5.1 6.3 6.5 3.6 5.1 16.5 18.0 5.3 5.5
Charge volume, L
Min (4 % Holdup) 1.2 6.0 15 0.575 3.3 1.0 4.6 0.7 4.9
Max (1 % Holdup) 4.8 24.0 60 2.3 13.0 4.2 10.4 2.8 19.4
A
Cooke, G. M. and Jameson, B. G. Analytical Chemistry, Vol 27, 1955, p. 1798.
B
Struck, R. T. and Kinner, C. R. Industrial and Engineering Chemistry, Vol 42, 1950, p. 77.
C
Cannon, M. R. Industrial and Engineering Chemistry, Vol 41, No. 9, 1949, p. 1953.
D
Bulletin 23, Scientific Development Co. P.O. Box 795, State College, PA 16801.
E
Cooke, G. M. Analytical Chemistry, Vol 39, 1967, p. 286.
F
Bulletin of Podbielniak Div. of Reliance Glass Works, P.O. Box 825, Bensenville, IL 60106.
G
Feldman, J., et al, Industrial and Engineering Chemistry, Vol 45, January 1953, p. 214.
H
Helipak Performance Characteristics, Begemean, C. R. and Turkal, P. J. (Laboratory Report of Podbielniak Inc.), 1950.
I
Umholtz, C. L. and Van Winkle, M. Petroleum Refiner, Vol 34, 1955, p. 114 for NH:MCH.
Pressure Drop Calculated from data obtained on o- and m-xylene binary.
J
Oldershaw, C. F. Industrial and Engineering Chemistry, Vol 13, 1941, p. 265.
K
Bragg, L. B. Industrial and Engineering Chemistry, Vol 49, 1957, p. 1062.
L
NA 5 not applicable.
D 2892
3.1.8.1 Discussion—In the case of an adiabatic column 4.5 From these data the TBP curves in mass or volume %,
when distilling a pure compound, the internal reflux is constant or both, versus AET are drawn.
from top to bottom and is equal to the reflux at the reflux
5. Significance and Use
divider. When distilling crude petroleum, the fractionation
occurring in the dynamic holdup will cause a temperature 5.1 This test method is one of a number of tests conducted
on a crude oil to determine its value. It provides an estimate of
gradient to be established with attendant greater amount of
internal reflux at the bottom of the column. the yields of fractions of various boiling ranges and is therefore
valuable in technical discussions of a commercial nature.
3.1.9 pressure drop—the difference between the pressure
5.2 This test method corresponds to the standard laboratory
measured in the condenser and the pressure measured in the
distillation efficiency referred to as 15/5. The fractions pro-
distillation flask.
duced can be analyzed as produced or combined to produce
3.1.9.1 Discussion—It is expressed in kilopascals (mm Hg)
samples for analytical studies, engineering and product quality
per metre of packed height for packed columns, or kilopascals
evaluations. The preparation and evaluation of such blends is
(mm Hg) overall for real plate columns. It is higher for
not part of this test method.
aromatics than for paraffins, and for higher molecular weights
5.3 This test method can be used as an analytical tool for
than for lighter molecules, at a given boilup rate.
examination of other petroleum mixtures with the exception of
3.1.10 reflux ratio, R—the ratio of reflux to distillate.
LPG, very light naphthas, and mixtures with initial boiling
3.1.10.1 Discussion—The vapor reaching the top of the
points above 400°C.
column is totally condensed and the resulting liquid is divided
into two parts. One part L (reflux), is returned to the column
6. Apparatus
and the other part, D (distillate), is withdrawn as product. The
6.1 Distillation at Atmospheric Pressure—All components
reflux ratio ( R 5 L/D), can vary from zero at total takeoff
must conform to the requirements specified below. Automatic
(L 5 0) to infinity at total reflux (D 5 0).
devices can be employed provided they meet the same require-
3.1.11 static hold-up or wettage—the quantity of liquid
ments. A typical apparatus is illustrated in Fig. 1.
retained in the column after draining at the end of a distillation.
6.1.1 Distillation Flask—The distillation flask shall be of a
3.1.11.1 Discussion—It is characteristic of the packing or
size that is at least 50 % larger than the volume of the charge.
the design of the plates, and depends on the composition of the
The size of the charge, between 1.0 and 30 L, is determined by
material in the column at the final cut point and on the final
the holdup characteristics of the fractionating column, as
temperature.
shown in Table 1 and described in Annex A2. The distillation
3.1.12 takeoff rate—the rate of product takeoff from the
flask shall have at least one sidearm.
reflux divider expressed in millilitres per hour.
6.1.1.1 The sidearm is used as a thermowell. It shall
3.1.13 theoretical plate—the section of a column required
terminate about 5 mm from the bottom of the flask to ensure its
to achieve thermodynamic equilibrium between a liquid and its
immersion at the end of the distillation. When a second sidearm
vapor.
is present, it can be used for pressure drop detection with a
3.1.13.1 Discussion—The height equivalent to one theoreti-
nitrogen bleed or for mechanical stirring, or both.
cal plate (HETP) for packed columns is expressed in millime-
6.1.1.2 If a magnetic stirrer is used with a spherical flask,
tres. In the case of real plate columns, the efficiency is
the flask shall have a slightly flattened or concave area at the
expressed as the percentage of one theoretical plate that is
bottom on which the magnetic stirrer can rotate without
achieved on one real plate.
grinding the glass. In this case, termination of the thermowell
4. Summary of Test Method
shall be off center 40 6 5 mm to avoid the magnetic stirring
4.1 A weighed sample of 1 to 30 L of stabilized crude bar. Boiling chips can be used as an alternative to a stirrer.
petroleum is distilled to a maximum temperature of 400°C 6.1.1.3 Warning—While the advantage of visibility in glass
AET in a fractionating column having an efficiency at total distillation flasks is desirable, flasks of glass may become
reflux of at least 14, but not greater than, 18 theoretical plates. hazardous
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.