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है”ह”ह

IS 1448-18 (1991): Methods of test for petroleum and itsproducts, Part 18: Distillation of Petroleum Products [PCD1: Methods of Measurement and Test for Petroleum, PetroleumProducts and Lubricants]

IS 1448 [ P : 18 ] : 1991

Indian Standard

METHODS OF TEST FOR PETROLEUM AND ITS PRODUCTS

[P:l8] DISTILLATION OF PETROLEUM PRODUCTS

( Second Revision )

First Reprint NOVEMBER 1998

UDC 665’6’048 : 543

0 BlS 1991

BUREAU OF INDIAN STANDARDS MANAK BHAVAN. 9 BAHADUR SHAH ZAPAR MARG

NEW DELHI 110002

May 1991 Price Group 7

-

Methods of Test for Petroleum, Petroleum Products and Lubricants Sectional Committee, PCD 1

FOREWORD

This Indian Standard [ P : 18 ] ( Second Revision ) was adopted by the Bureau of Indian Standards, after the draft finalized by the Methods of Test for Petroleum, Petroleum Products and Lubricants Sectional Committee had been approved by the Petroleum, Coal and Related Products Division Council.

IS 1448 1 P : 18 ] : 1991

Indian Standard

METHODS OF TEST FOR PETROLEUM AND ITS PRODUCTS

[?:18]

DISTILLATION OF PETROLEUM PRODUCTS

( Second Revision )

Adapted with permission from the Joint Publication ASTM D 86-82 and IP 123/84

I

1 SCOPE

1.1 This method of test covers the distillation of motor gasolines, aviation gasolines, aviation turbine fuels, special boiling point spirits, napthas, white spirit, kerosenes, gas oils, distillate fuel oils and similar petroleum products.

NOTE -This method is not intended for the distillation of natural gasoline and volatile organic liquids or relatively pure solvents.

1.2 For the distillation of ajjiation turbine fuels and other products of such wide boiling range that the low distillation thermometer specified in Group 3 of Table 1 is inadequate, this method may be applied by substituting the high distillation thermometer together with the other test condi- tions specified in Group 3 ( see 8.3 1.

2 SUMMARY OF THE METHOD

2.1 A 100 ml sample is distilled under prescribed conditions which are appropriate to its nature ( see Table 1 ). Systematic observations of thermometer readings and volumes of condensate are made, and from the data, the results of the test are calculated and reported.

3 SIGNIFICANCE

3.1 Distillation f volatility ) characteristics of petroleum products are indicative of performance in their intended applications. Petroleum product specifications generally include distillation limits to ensure products of suitable volatility performance.

3.2 The empirical results obtained by use of this distillation method have been found to correlate with automotive equipment performance factors and with other characteristics of petroleum pro- ducts related to \,olatility.

4 TERMlNOLOGY

4.0 For the purpose of this standard, the following definitions shall apply.

4.1 iuitial Boiling Point

The thermometer reading which is observed at the instant that the first drop of condensate falls from the lower end of the condenser tube,

4.2 End-Point or Final Boiling Point

The maximum thermometer reading obtained during the test. This usually occurs after the evaporation of all liquid from the bottom of the flask. The term ‘maximum temperature’ is a frequently used synonym.

4.3 Dry Point

The thermometer reading observed at the instant the last drop of liquid evaporates from the lowest point in the flask. Any drops or film of liquid on the side of the flask or on the thermometer are disregarded.

NO 1-E - The end ( final boiling ) point, rather than the dry point, is intended for general use. The dry point may be reported in connection with special purpose naphthas. such as used in the paint industry. Also. it should be substituted for the end (final boiling 1 point whenever the sample is of such a nature that the precision of the end ( final boiling) point cannot consistently meet the requirements given in 10.

4.4 Decomposition Point

The thermometer reading which coincides with the first indication of thermal decomposition of the liquid in the flask.

SO1 E - Characteristic indications of thermal decom- Ix’sillon ale an evoiution of fumes, and erratic thermometer rL,adings which usual!y show a decided decreax after any attempt is made to adjust the heat.

4.5 Percent Recovered

The volume in ml of condensate observed in the receiving graduate, in connection with a simult- aneous thermometer reading.

4.6 Percent Recovery

The maximum percent recovered, as observed in accordance with 8.7.

4.7 Percent Total Recovery

The combined percent recovery and residue in the flask, as observed in accordance with 8.8.

4.8 Percent Loss

100 minus the percent total recovery.

IS 1448lP:181:1991

Table 1 Test Conditions

( Clauses 1.2 and 2. I )

SI No. Requirements

1) Sampic characteristics

a) Vapour pressure at 37’8°C. ha1

b) Distillation

2)

i) Initial boiling point’

ii) End ( final boiling ) point*

Preparation of apparatus: a) Thrrmomete~

i) ASTM thermopleter No. ii) IP thermometer No.

b) Diameter of hole in flask supfxxt. mm

c) Temperature at slart of test

i) Flask and thermometer

ii) Flask support and shield

3)

iii) Graduate and 100 ml charge

d) Flask

Conditions during test procedure:

a) Temperature of condenser bath

b) Temperature of bath around graduate

c) Time from first application of heat to initial boiling point. minutes

d) Time from initial boiling point to 5 percent recovered. seconds

e) Uniform average of condensation from 5 percent recovered to 5 ml residue in flask. ml/min

f) 1 ime from 5 ml residue to end point. minute

Croup 1 Goup 2 Group 3 Group 4

0’66 or above ISelow 0’66 Helo\\ 0’66 HeloW 0.66

-

250°C or below 25O’C or below Above 250°C

100°C or belo\\ Aho\c 100°C

:I buvc ‘50°C

Low; 7C 5C

37’5

Lo\\: 7c 5c

37’5

Low; 7c SC

High; YC K

50 50

l3-18’C 13-18°C I;-18°C

Not above Not above Not above ambient ambient ambient l3-18°C 13-18°C l3-18°C

I25 ml 125 ml 125 1111

o- 1°C

13-18°C

5-10

60-75

J-5

3-5

o--4°C

l3-18°C

5-10

60-75

4-5

3-5

O--J”<

13-18°C

S-10

-

4-5

5 .\icr.u

13°C to ambient

125 Illl

0-60'Ct

Within 23°C of temperature of distillation charge

5-15

*As determined under all test conditions of the group concerned.

tThe proper condenser bath temperature will depend upon the wax content of the sample and of it5 distrllation fraction. The minimum temperature which permits satisfactory operation should bs used. In ,general a bath temperature in 0 to 4°C range is suitable for kerosene’ATF.

4.9 Percent Residue

The percent total recovery minus the percent recovery, or the volume of residue in miiliiitres if measured directly.

4.10 Percent Evaporated

The sum of the percent recovered and the per- cent loss.

5 APPARATUS

5.0 A typical assembly of apparatus using gas burner and electric heater respectively is shown in Fig. I and Fig. 2. The apparatus consists of the following parts.

5.1 Distillation Flasks

Distillation flasks of heat-resistant glass and of capacity, shape and dimensions shown in Fig. 3.

5.2 Condenser and Cooling Bath

Typical approved types of condenser and cooling bath are included in Fig. I and 2. The condenser shall be made of seamless brass tubing, 560 mnl

in length. It shall be 14 mm in outside diameter, and shall have a wail thickness of 0’79 to 0’91 mm. The condenser shall be set so that approxi- mately 390 mm of the tube will be in contact with the cooling medium, with about 50 mm outside the cooling bath at the upper end, and about 114 mm outside at the lower end. The length of tube projecting at the upper end shall be straight and shall be set at an angle of 75” with the vertical. The section of the tube inside the cooling bath may be either straight or bent in any suitable continuous, smooth curve. The average gradient shall be 0’26 mm per linear mm of condenser tube ( sine of angle of 15” ). and no section of the immersed portion 01’ the con- denser tube shall have a gradient less than 0’24 and 0’28 mm per linear mm of tube. The projecting lower portion of the condenser tube shall be cur\.ed downward lbr ;I length of 76 mm and slightly backward so as to ensure contact with the wail of the recciGng graduate at a point approxi- mately 25 to 32 mm below the top of the graduate when it is in position to receive the distillate. The lower end of the condemer tube shall be cut off at an acute angle so that the tip may be brought into contact with the wall of the cylinder.

2

IS 1448 I P : 18 1 : 1991

FLASK-SUPPORT

FLASK-SUPPORT

f

BATH COVER

ASBESTOS

SUPPORT 1

FIG. 1 ASSEMBLY OF APPARATUS FOR DISTILLATION USING GAS BURNER

52.1 The capacity of the cooling bath shall be not less than 5’55 litres of cooling medium. The arrangement of the tube in the cooling bath shall be such that its centre line shall be not less than 32 mm below the plane of the top of the bath at its point of entrance and not less than 19’0 mm above the floor of the bath at its exit.

5.2.2 Clearance between the condenser tube and the walls of the bath shall be at least 12’7 mm except for the sections adjacent to the points of entrance and exit. Multipie installations are permissible, provided they conform to the dimensional requirements and the capacity of the

bath is not less than 5’55 litres per tube.

5.3 Metal Shield or Enclosure for Flask

5.3.1 Type 1 shield (see Fig. 1 ) is 480 mm high, 280 mm long, and 200 mm wide, made of sheet metal of approximately 0’8 mm. It shall have a door on one narrow side, and two openings 25 mm in diameter, equally spared in each of the two narrow sides, with a slot cut in one side for the vapour tube. The centres of these four openings shall be 216 mm below the top of the shield. There shall be three 12’7 mm holes in each of the four sides, with their centres 25 mm above the base of the shield.

3

IS 1448 I P : 18 I : 1991

I r

__----------- 1

I I

CONDE NSE R-\

BLOTTING PAPER-,

GRADUATED CYLINDER\

I I

-4 L i I’ ‘t I ’ ---7

‘I\ J II r

1. 11 lr - - -

SHIELD’ ( TYPE 2)

‘,i 1,’

@I

0

-CONDENSER TUBE

FLASK

ASBESTOS BOARD

ELECTRIC-HEATING MANTLE

FLASK-SUPPORT PLATFORM

FLASK-ADJUSTING KNOB

SWtTCH

HEAt- ADJUSTING

DIAL

~PEN-~oTTOM

FIG. 1 ASSEMBLY OF APPARATUS FOR DISTILLATION USING ELECTRIC HEATP~R

4

IS 1448 I P : 18 I : 1991

[BEA REINFORCING

1 POLISHED1

6.5 TO 75 00 WALL THICKNESS t*oow5

.\I1 dimensions in mill:mctres

FIG. 3 DISIILLATION FLASK ( 125 ml )

5.3.2 Type 2 shield ( see Fig. 2 ) is 440 mm high, but the part below may be omitted provided this 200 mm lonp, and 200 mm wide, made of sheet does not cause the distillation flask to be exposed metal of approximately 0’8 mm, with a window to draughts. on the front bide. The open bottom of the shield shall be spaced approxima!ely 50 mm frond the base of the unit. The rear of the shield shall have

5.4 Heat Source

an elliptical hold for the vapour tube. A flask- adjusting knob shall be located on the front of the 5.4.1 Gas Bwxer

shield for adiusting the flask support. Also, a heat- adjusting indicating dial shall -t-i used to provide Gas burner (see Fig. 1 1. 50 constructed that stepless heat control n,hen the electric heater is used. sufficient heat from the available gas can be The entire mcchsnism shall be built into the bottom portion of the shield. N’hen an electric heater

obtained to distil the product at the specified rate.

I\ employed, the portion of the shield above the A sensitive regulating valve and gas pressure governor to give complete control of heating may

board shall be the same as with the gas burner, be provided.

5

IS 1448 I P : 18 1 : 1991

5.4.2 Electric Heater

Electric heater (see Fig. 2), may be used instead of a gas burner, provided it is capable of bringing over the first drop from a cold start within the time specified and of continuing the distillation at the specified rate. Heater units. of low heat retention, adjustable from 0 - 1 000 W, have been found satisfactory.

5.5 Flask Support

5.5.1 Type I .for Use with Gas Burner ( see Fig. I ) A ring support of the ordinary laboratory type, 100 mm or larger in diameter, supported on a stand inside the shield, or a platform adjustable from the outside of the shield, may be used.

Two ceramic heat resistant boards, 3 to 7 mm in thickness, shall rest upon the ring of the platform, whichever is used. The board immediately above the ring or platform shall have a centred opening 76 to 100 mm in diameter and outside line dimen- sions slightly smaller than the inside boundaries of the shield.

The second or flask support board shall be slightly smaller in outside dimensions than the first board and shall have a 37’5 mm or a 50 mm centred opening. It shall be 3 to 6 mm in thick- ness at the centre hole rim. This flask support board may be moved slightly in accordance with

the directions for placing the distillation flask, and direct heat shall be applied to the flask only through the opening in this board.

5.5.2 Type 2 for Use with Electric Heater (see Fig. 2 )

The top of the electric heater shall consist of a ceramic heat resistant flask support board with a centred hole as specified, and a thickness of 3 to 6 mm at the centre hole rim. ‘Provision shall be made for moving the heater unit, with its top, in order to place the distillation flask so that direct heat shall be applied to the flask only through the opening in the flask support board.

5.6 Graduated Cylinder

A loo-ml graduated cylinder with I ml subdivi- sions shall be provided. Construction details and tolerances are given in Fig. 4.

5.7 Thermometers

5.7.1 Conforming to the requiremeqts given below. For partly or fully automatic apparatus and procedure, an alternative means of measuring or recording temperature may also be used provided this gives the same reading under distillation test conditions and has a precision not less than that of the prescribed thermometer:

Characteristic

Range

Graduation

Immersion

Overall length

Stem diameter

Bulb shape

Bulb length

Bulb diameter

Length of graduated portion

Distance from bottom of bulb to 0°C

Longer lines at each

Figured at each

Expansion chamber

Top finish

Scale error not to exceed I

Thrrmometcr No. 1

-2°C to $3OO”C

1°C

Total

380f 10 mm

5’5 to 8’0 mm

Cylindrical

Sto 16mm

Not less than 5’5 mm and not greater then stem

223 to 254 mm

100 to 110 mm

5°C

10°C

Required

Ring

+ 0’5°C up to 150°C & 1°C above 150°C

Thermometer No. 2

-27z to $4OO”C

1°C

Total

380f 10 mm

5’5 to 8’0 mm

Cylindrical

8 to 16 mm

Not less than 5’5 mm and not greater than stem

288 to 329 mm

25 to 45 mm

5°C

10°C

Required

Ring

il”C up to-300°C f 1’5°C above 300°C

NOTE - I’hermometres with the Institute of Petroleum designation II’ 5C and 6C conform to the requirements for thelmometres No. 1 and 2 respectively.

6

1s 1448 [ P : 18 I : 1991

‘OURlNG LIP

_

: t

248 TO 260

SCALE LENGTH

178 TO 203

POLlSHE

I

I

I a I

I I

--I C -I - I

= I

- I

-1 _I

I----&. I-- I=

t t

15 I

t t- IS t I---- t

1.5 TO 20

SHAPE OF THE FOOT(OPTIONAL)

All dimensions in millimctres.

FIG. 4 GRADUATED CYLINDER

7

IS1448IP:181:1991

5.7.2 The thermometer shall bear a certificate from the National Physical Laboratory, New Delhi, or any other institution authorized by the Government of India to issue such certificate.

6 SAMPLE

6.1 In the case of any product having a Reid Vapour Pressure of 655 mbar or higher, cool the sample bottle to a temperature in the range 13°C to 18°C. Collect the sample in the previously cooled bottle, preferably by immersing the bottle in the liquid, where possible, and discarding the first sample. Where immersion is not possible, the sample shall be drawn off into the previously cooled bottle in such a manner that agitation is kept at a minimum. Close the bottle immediately with a tight-fitting stopper, and place it in an ice bath or refrigerator capable of maintaining the sample at a temperature not to exceed 15°C.

6.2 Samples of materials that visibly contain water are not suitable for testing. If the sample is not dry, and the initial boiling point is below 66”C, obtain another sa’mple which is free from suspended water for the test. If the initial boiling point is above 66”C, shake the sample with anhydrous sodium sulphate or other suitable drying agent and separate it from the drying agent by decanting.

7 PREPARATION OF APPARATUS

7.1 Refer to Table I and select the flask support, and thermometer which are required by the sample to be tested. Bring the respective temperatures of the flask, thermometer, graduate, flask support, and shield to their required values for starting the test.

7.2 Fill the condenser box to cover the condenser tube with any non-flammable coolant which is suitable for the temperature required by Table 1, such as chopped ice, water, brine, or ethylene giycol solution. If chopped ice is used, add sufficient water to cover the condenser tube. If necessary, make any suitable provision, such as circulation, stirring or air blowing, so as to maintain the required condenser bath tempera- ture throughout the test. Similarly, make any necessary provision so that the temperature of the bath around the graduate will remain within the limits required in Table 1.

7.3 Remove any residual liquid in the condenser tube by swabbing with a piece of soft, lint-free cloth attached to a cord or copper wire.

7.4 Bring the temperature of the sample within the range prescribed in Table 1. Measure 100 ml of the sample in the graduated cylinder and transfer it as completely as practicable to the distillation flask, taking care that none of the liquid flows into the vapour.tube.

7.5 Fit the thermometer, provided with a snug- litting, well-rolled cork, tightly into the neck of

the flask so that the bulb is centred in the neck and the lower end of the capillary is level with the highest point on the bottom of the inner wall of the vapour tube ( see Fig. 5 ).

7.6 Place the flask containing the charge in its support; and by means of a cork through which the qapour tube has been passed, make a tight connection with the condenser tube. Adjust the flask so that it is in a vertical position, and so that the vapour tube extends into the condenser tube for a distance of 25 to 50 mm.

7.7 Place the graduate that was used to measure the charge, without drying, into its bath under the lower end of the condenser tube so that the end of the condenser tube is centred in the graduate and extends therein for a distance of at least 25 mm, but not below the 100-ml mark. Cover the graduate closely with a piece of blotting paper, or similar material, suitably weighted, which has been cut to fit the condenser tube snugly. Maintain the level of the bath around the graduate so that it is at least as high as the 100 ml mark.

7.8 Note and record the prevailing barometric pressure, and proceed at once with the distillation, as given in 8.

8 PROCEDURE

8.1 Apply heat to the distillation flask and contents. The heating at this stage shall be so regulated that the time interval between the first application of heat and the initial boiling point does not exceed the limit as prescribed in Table 1.

8.2 Immediately after observing the initial boiling point, move the graduate so that the tip of the condenser touches its inner wall. Continue to regulate the heating so that the rate of con- densation into the graduate shall be uniform and within the limits prescribed in Table 1. Repeat any distillation which did not meet the fore- going conditions.

8.3 In the interval between the initial boiling point and the end of the distillation, observe and record whatever data are necessary for the calculation and reporting of the results of the test as prescribed in 9. These observed data may include thermometer readings at prescribed percentages recovered, or percentages recovered at prescribed thermometer readings, or both. Record all volumes in the graduate to the nearest 0’5 ml and all thermometer readings to the nearest 0’5°C.

NOTE - In cases in which no soxific data reauire- nxnts have been indicated, recorh the initial boiling point, the end point (final boiling point ) or dry point, or both. and thermometer readings, at 5 pxcent and t)5 pxcent recovered and at each multiple of 10 percent recovered from 10 to 90, inclusive.

8.4 If a decomposition point is observed, dis- continue the heating and resume the procedure

8

lS1448IP:lSI: 1991

I I I . _

i ‘1 ?T=+_

.=- .- -

5 .,

FIG. 5 POSITION OFTHERMOMETER IN DISTILLATION FLASK

9

IS 1448 [ P : 18 1 : 1991

9.5 After barometric corrections of the thermo- meter readings have been made, if required, the following data require no further calculation prior to reportin,. 0’ initial boiling point, dry point, end ( final boiling ) point. decomposition point, percent recovery, percent total recovery, and all pairs of corresponding values involving per- centaaes recovered and thermometer readings. Percent loss and percent residue are calculated in accordance with their respective definitions as set forth in 4.8 and 4.9.

9.6 It is advisable to base the report on relation- ships between thermometer readings and per- centages evaporated in any case in which the sample is a gasoline, or any other product classed under Group 1 in Table 1, or in which the percent loss is greater than 2’0. Otherwise, the report may be based on relationships between thermo- meter readings and percentages evaporated or recovered. Every report shall indicate clearly which basis has been used.

9.7 To report percentages ev:lporaied at prescri- bed thermometer readings, add the percent loss to each of the obser\ed pxcentages recovered ;tt the prescribed thermometer readings, and report these results as the respective percentages evaporated

Rn = percent recovered adjacent to, and higher than R, at which a thermometer reading ‘TH’ was noted; and

RL = percent recovered adjacent to, and lower than R, at which a thermometer reading ‘TL’ was noted.

NOTES

1 Values obtained by the arithmetical procedure are affected by the extent to which the distillation graph is non-linear. Intervals between successive data points shall, at any stage of the test, be at least as narrow as indicated in Note under 8.3. In no casae shall a calculation bz made which involved extra- polation.

2 See Annex A for numerical examples illustrating the foregoing graphical and arithmetical procedures.

9.9 If thermometer readings are corrected to 1 013 mbar ( 760 mm Hg ) pressure, the actual loss shall be corrected to I 0 13 mbar ( 760 mm Hg ) pressure, according to the equation given below. The corresponding corrected percent recovery is com- puted on the basis that it is greater than the actual recovery by the same amount as the corrected loss is less than the actual loss. When reporting data, state whether the corrections have or have not been applied.

Corrected loss = AL+ B, . . . . . , etc,. . .pressure

where

9.8 To report thermometer readings at prescribed L L-_

percentages evaporated. use either of the t14.0 following proccdurcs, and indicate on the report whether the graphical procedure or tRe :trithrneti-

A :tnd B =

cal procedure has been used.

9.8.1 Grapllicctl Procedure

percent loss as calculated from test data; and

numerical constants, the values of which depend upon the prevailing barometric pressure. These constants are listed in Table 3, in connection with the prevailing pressure.

Using go-aph paper \vith unifor;;l subdivisions, plot each thermometer reading ( corrected for

Table 3 Values of the Constant ‘A’ and ‘B’ __ . . _

barometric pressure, if required ) against its Used in Obtaining Corrected Distillation Loss

corresponding percent recovered. Plot the initial Ohserved Barnmetric /t B boiling point at 0 percent recovered. Draw a I’ressure

( mm Ha )

560

570

580

590

600

610

620

630

640

650

660

670

680

690

700

7 IO

720

730

740

:50

760

_ . smooth curve <nnnecting the points. For each prescribed percent evaporated, deduct the distillation loss, in order to obtain the corres- ponding percent reco\,ered. and take from the graph the thermometer reading which this percent recovered indicates (.ree Note under 9.8.2). Values obtained by graphic:tl interpolation procedures are atyected by the cart with the plot is made.

Deduct the distillation loss from each prescribed percentage evaporated in crder (0 obtain. the corresponding percentage recovered. Calculate each required thermometer reading as follows:

T_ TL + ( TH -- TL ) ( R -- RL ) ( RH -- RL )

lllIX3l

747

760

773

787

800

Xl3

826

840

853

866

880

Is93

goi,

920

933

9-16

960

thermon~rter re,rding at the prescribed percent evaporated:

percent recovered corresponding to the . . .

973

986

1 000 , n,,

0.231 0’3S4

0’240 0.380

0’250 0’375

0’261 0‘369

0 273 0’363

0.286 0.357

0’300 0’350

0’316 0’342

0.333 0’333

0’353 0’ 323

0’375 0’312

0’400 0.300

0’428 0’286

0’461 0’269

9’500 0.250

0’545 0’227

0’600 0.200

0’667 0.166

0’750 0’ I25

O’b57 0.071

1’000 0’000 prescrtbed percent evaporated: L “1.1

11

A

B

C

D

IS 1448 I P : 18 I : 1991

10 PRECISION

10.0 The following criteria shall be used for judging the acceptability of result (95 percent confidence ).

10.1 Duplicate results obtained by the same

-t

I 3

I 2

1

A

4:

2

“C

I 3

I 2

1

C

%

I

2 3

0

operator and apparatus should not be considered suspect unless they differ by more than the repeata- bility which according to Fig. 6, is appropriate to the test result obtained and to the rate of change in thermometer reading which prevailed at the stage at which the result was obtained.

REPnoouclelLlTY f I

“t

I 7

t

6

,t 5

t 4

t 3

I

A

T

I 5

I 4

I

3

8

Initial Boiling Point In “C.

End Point or Dry Point in “C.

Thermometer Reading at Prescribed Percent in ‘C.

“C

I 8

t 7

t 6

t

5

t

4

t

3

t 2

1

C

‘1.

1

r so

- 4O

- 3O

- 2O

~

lo

O0

Evaporated or Recovered

Percent Evaporated or Recovered at Prescribed Thermometer Reading in Percent.

FIG. 6 PKECISIUN OF DISTILLATION Mtmwn

12

IS 1448 I P : 18 1 : 1991

10.2 The results obtained by each of two laboratories, should not be considered suspect unless the two results differ by more than the reproducibility which, according to Fig. 6, is appropriate to the test result obtained arid to the rate of change in thermometer reading which prevailed at the stage at which the result was obtained.

10.3 To facilitate the use of Fig. 6, the rate of 10.4 In Fig. 6, it will be noted that the left and change in thermometer reading in degrees Celsius right marginal scales, representing the rate of per the percentage evaporated or recovered, at any point between the initial boiling point and

change in thermometer readir1.g. are identical. This is to facilitate the establishing of ;I horizontal

the end ( or final boiling ) point or dry point. line across the chart and at the required level, should be assumed to be the same as the average which may be done in any convenient manner. rate between two data points which are equidis- Wherever this line intersects the appropriate pre- tant above and below the point in question. The cision scale, the zone in which such intersection span from the point in question to either of the other data points should not represent more than

falls will indicate the expected repeatability or reproducibility.

10 percent evaporated or recovesed in any case, nor more than 5 percent if the point in question is not included in the IO-90 percent range. For the initial boiling point end ( or final boiling ) point, or dry point, the rate of change should be assumed to be the same as the average rate over an interval, not to exceed 5 percent evaporated or recovered, between the extreme point and the next data point above or below it.

ANNEX A

( Clatrse 9.8 )

( NON-MANDATORY INFORMATION )

EXAMPLES ILLUSTRATING CALCULATIONS OF THERMOMETER READINGS AT PRESCRIBED PERCENTAGES EVAPORATED

A-l Assume observed distillation data as follows:

“C

Initial boiling point 36’5

5 % recovered 45’5

10% recovered. 54

20% recovered 65’5

30% recovered 17

40% recovered 89’5

50% recovered 101’5

70 % recovered 131

80% recovered 149

90% recovered 171

95 % recovered 186’5

End ( final boiling ) point 309

Recovery, percent 97’5

Residue, percent 1’0

Loss, percent 1’5

A-2 To apply the graphical method. plot the data in A-l as indicated in Fig. 7. Read from the graph thermometer readings at percentages

recovered correspondin g to prescrr bed percentages evaporated, as shown by the following examples:

Prerribetl Correspordirlg Percent Petwnt

Evaporated Rem wrd

5 3’5 SO 48’5 90 88’5

A-3 To apply the arithmetical method, substitute appropriate data from A-l in the general formula given in 9.8 as shown in the following examples:

1) Thermometer reading at 5 percent evapor- ated ( 3’5 percent recovered ): f

T,,C _ 36,5 +(45’5--36’5) (3*5--O) - (5--O)

-- 43

2) Thermometer reading at 50 percent evapor- ated ( 48’5 percent recovereLi !:

l.,,c _ s9,5 +( lOl’5-88”). (45.5 ---it)‘0 ) -- ( W-4) )

YY’5 3) Thermometer reading at 90 percent ev;lpor-

ated ( 88’5 percent recovered ):

( 171.-139) (SS’:;-SO-t)) T”C = 1 jy L ~________~

( NJ -x0 ) 107’5

13

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Amendments Issued Since Publication

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