Prediction of Octane Numbers and Lead Susceptibilities of

Methods for the prediction of the octane are plotted against the relative now in US0 are generally variety of constituent gasoline types or blending s...
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Prediction of Octane Numbers and Lead Susceptibilities of Gasoline Blends DUBOIS EASTMAN The Texas Company, Port Arthur, Texas

T H E commercial gasolines

are plotted against the relative Methods for the prediction of the octane now in US0 are generally proportions Of the two Stocks numbers and lead response characteristics of gasoline blends are presented. blended. The octane values of prepared by blending a variety of constituent gasoline the two base stocks are shown numbers are predicted by means Of a types or blending stocks which as points A and B, and a typical ing coefficient which has been correlated have been prepared by various blend is shown as point The refining procedures. These with the difference in octane sensitivity deviation of C from the straight blends are made with due re. between the stocks blended. A mo&ficaline connecting A and repregard t o the availability of the sents the deviation ( d ) of this tion of the Hebl, Rendel, and ,-arton chart various stocks and to the propblend from an arithmetic is presented for the erties desired in the final blend. Of lead reblending relation. The magniTetraethyllead is usually added SPonse, and correlations for the Prediction tude of the deviation has been insufficient quantity to obtain of this factor from sulfur content and ocfound to depend on the relative proportions in which the the desired octane number in tane sensitivity are given. the finished gasoline. two stocks are the Methods for the prediction of the lead Since the octane number of difference in octane number response of blends are described. It is between the two base stocks the finished product is a matter of importance and since the Pointed out that all the correlations are used, and the difference in cost of the tetraethyllead reempirical and should be verified before character between the two gasolines. being applied to unusual stocks. quired is often substantial, it In studying a large number is desirable that methods be of blends, it has been found available for the prediction of that curve ACB can be satisfactorily represented as a skewed the octane numbers of blends, and for the prediction of the lead susceptibility or response of these blends to the addition parabola such that for blends of any two base stocks the ratio d/&is a constant when 1: is taken as the volumetric of tetraethvllead. fraction of either A or B in the blend, whichever is the smaller. Prediction of Octane Number It has also been found that a factor may be obtained which is dependent only on the difference in character of the stocks Data on pure hydrocarbons (3) and experience with commercial gasolines have shown that the octane values of blended if this ratio d / f l is divided by the difference in octane number of the two stocks. Thus: blends of saturated hydrocarbon types, such as paraffins and naphthenes, are related arithmetically to the octane numbers d c=of the components and to the relative proportions in which ~5Ao they are blended. If, however, these materials are blended where c = blending coefficient which is dependent only on the with unsaturated fractions containing olefinic or aromatic difference in character of the two stocks types, substand = deviation of observed octane value from arithmetic tial deviations average x = volumetric fraction of either stock in the blend, from an arithmetic relation are whichever is smaller AO = difference in octane number between the two stocks commonly enblended countered. . A0 The behavior The difference in character c& the two stocks is convenof a typical twoiently measured in terms of their respective octane sensitivicomponent blend ties, where the term “sensitivity” refers to the difference in of the latter type octane number as measured by the C. F. R. Research (1939) is illustrated in method and by the C. F. R. Motor or A. S. T. M. method. F i g u r e 1, i n It has been found that values of the blending coefficient, c, -x--i whioh the octane are not the same for the Research and Motor methods and A COMPOSITION -VOL. X ‘wtB values of various that the respective values of C M and C R can be correlated FIGURE1. TYPICAL BLENDINQ blends of base empirically with the sensitivity factor AS2 as in Figure 2. stocks A and B I n this relation c is the blending coefficient defined above, RELATIONS 1555

octane

c.

I N D U S T R 1.AL A N D E N G I N E E R I N G C H E M I S T R Y

1556

/ I

0'40L-

Component A C. F. R . Motor method or A. 8. T. &f. 58.3 octane No. C. F. R. Research method (1939) octane 58.G NO. Volume % in blend 40

C

B

D

82.9

70.5

67.0

98.4 40

79.2 10

73.8

8.7 76 76 0.112 12.2 1.37

5.9 35 35

10

Method

0.30

0

Vol. 33, No. 12

0.3 0.1

..

.. .. ..

15.5 240 240 0.445 24.6 10.95

0.065

9.6

0.62

+ (1.37)(0.10) + (0.62)(0.10) 0.60 - 4.380 + 0.137 + 0.062 = 4.579 - 7.63

average C A O=

(10.95)(0.40)

0.060

0.60

I

I

-0ig

I

I

50 SENSITIVITY

0

50

100 FACTOR

1

4; = 4/0.40

I

I

150

250

200

AS'

OF BLENDING COEFFICIENT FIGURE 2. EVALUATION

and the sensitivity factor AS2 is the square of the octane sensitivity for the higher octane stock less the square of the octane sensitivity for the lower octane stock. This may be expressed mathematically as follows :

= 0.632 d =c ~ G A= o (7.63)(0.632) = 4.82 octane of blend = (58.3)(0.40) (82.9)(0.40) (70.5)(0.10) (67.9)(0.10) 4.82 = 23.32 f 33.16 7.05 6.79 4.82 = 75.1 (C. F. R. Motor method)

++ +

+

+

+-

+

With the method for the prediction of the unleaded octane values of gasoline blends established, a study was made of methods for the prediction of the response of such blends to the addition of tetraethyllead.

Lead Blending Chart factor BR E sensitivity octane sensitivity C. F. R. Research method

where A ( S *

=

fif =

(1939) octane No. C. F. R. Motor method (A. S. T. M.) octane NO.

Subscripts H = stock of higher octane No.; L

=

stock of lover octane No.

The following example illustrates the method of calculation used : To find the octane value of a blend of 60 volume per cent A and 40 volume per cent B where the octane values of A and B are as follows:

C. F. R. Motor Stock A

B

or A. 9. T. M . Octane No. 58.3 82.9

C. F. R . Researoh (1939) Octane No. 58.6 98.4

A S z = 240

- 0.1

S

-

R M 0.3 15.5

3

Sa

-

The rate of increase of the octane number of gasolines on the addition of tetraethyllead has been the subject of extended studies by Hebl, Rendel, and Garton ( 2 ) . They developed charts on which the relation of octane number to lead addition appear as substantially straight lines. These charts have proved satisfactory for most gasolines but have shown a tendency toward nonlinear relations for high-octane-number saturated gasolines of the aviation type. I n reviewing a large amount of lead response data, it became apparent that this tendency in the revised Hebl, Rendel, and Garton chart 100

-

(R M), 0.1 240

90

= 240

The C. F. R. Motor method @ending coefficient,c,v, from Figure 2 is 0.445. Then d = C ~ X A=O(0.445)(d0.40)(82.9 58.3) = (0.445){0.632)(24.6)

80

= 6.92.

+ (0.4) + 33.16 = 68.14. The predicted octane number is 68.14 + 6.92 = 75.1 (C. F. R. The anthmetic average octane number is (0.6)(58.3)

70

(82.9) = 34.98

Motor method).

60

Y

When more than two components are blended, calculations can be made stepwise, but the procedure is tedious and the following method has been found more convenient. I n this method the lowest octane number component is considered as the base, and values of the blending coefficient c are evaluated as above for each of the higher octane number components relative to the base. The products of each of these blending coefficients and the respective differences in octane number relative to the base are then averaged according to the relative proportions of the various higher octane components. This average value of CAOis then multiplied by the square root of the volumetric fraction of the base or of the ~ u m of the higher octane components in the blend, whichever is the smaller. This procedure is illustrated in the following example: To fmd the C. F. R. Motor method octane number of the following blend:

so

40

30

20

10

0

TEfRAETWL

LEAD

GC./GAL.

FIGURE 3. TETRAETHYLLEAD BLENDING CHART

December, 1941

INDUSTRIAL AND ENGINEERING CHEMISTRY

TABLEI. COMPRESSION RATIOSCALEFOR OCTANE AXIS VALVES OF Y

,

FOR LEADAXISVALVESOF 100 X TABLE11. SCALE

Co. T.

E.L./

Ootane

No.

0.0

20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 76 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.6 12.1 12.6 13.1 13.6 14.1 14.6 15.2 15.8 16.4 17.0 17.7 18.4 19.1 19.8 20.5 21.2 21.9 22.6 23.3 24.0 24.7 25.5 26.3 27.1 27.9 28.8 29.7 30.6 31.6 32.6 33.6 34.7 35.8 36.9 38.0 39.1 40.2 41.3 42.5 43.7 44.9 46.1 47.3 48.5 49.7 51.0 52.3 53.7 55.1 56.5 58.0 59.5 61.1 62.8 64.6 66.4 68.3 70.2 72.1 74.1 76.1 78.2 80.4 82.6 84.9 87.2 89.6 92.0 94.5 97.2 100.0

0.1 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.6 12.1 12.6 13.1 13.6 14.1 14.7 16.3 15.9 16.5 17.1 17.8 18.5 19.2 19.9 20.6 21.3 22.0 22.7 23.3 24.0 24.8 25.6 26.4 27.2 28.0 28.9 29.8 30.7 31.7 32.7 33.7 34.8 25.9 37.0 38.1 39.2 40.3 41.4 42.6 43.8 45.0 46.2 47.4 48.6 49.8 51.1 52.4 53.8 55.2 56.7 58.2 59.7 61.3 63.0 64.8 66.6 68.5 70.4 72.3 74.3 76.3 78.4 80.6 82.8 85.1 87.4 89.8 92.3 94.8 97.5

0.2 7.1 7.6 8.1 8.6 9.1 9.6 10.1 10.6 11.1 11.7 12.2 12.7 13.2 13.7 14.2 14.7 15.3 15.9 16.5 17.1 17.8 18.5 19.2 19.9 20.6 21.3 22.0 22.7 23.4 24.1 24.8 25.7 26.5 27.3 28.1 29.0 29.9 30.8 31.8 32.8 33.8 34.9 36.0 37.1 38.2 39.3 40.4 41.5 42.7 43.9 45.1 46.3 47.5 48.7 50.0 51.3 52.5 54.0 55.4 56.8 58.3 59.8 61.4 63.2 65.0 66.8 68.7 70.6 72.5 74.5 76.5 78.6 80.8 83.1 85.4 87.7 90.1 92.5 95.0 97.8

0.3

7.1 7.6 8.1 8.6 9.1 9.6

10.1

10.6 11.1 11.7 12.2 12.7 13.2 13.7 14.2 14.8 15.4 16.0 16.6 17.2 17.9 18.6 19.3 20.0 20.7 21.4 22.1 22.8 23.5 24.2 24.9 25.7 26.5 27.3 28.2 29.1 30.0 30.9 31.9 32.9 33.9 35.0 36.1 37.2 38.3 39.4 40.5 41.7 42.9 44.1 45.3 46.5 47.7 48.9 50.1 51.4 52.7 54.1 55.5 57.0 58.5 60.0 61.6 63.3 65.1 67.0 68.9 70.8 72.7 74.7 76.7 78.9 81.1 83.3 85.6 87.9 90.3 92.8 95.3 98.0

0.4 7.2 7.7 8.2 8.7 9.2 9.7 10.2 10.7 11.2 11.8 12.3 12.8 13.3 13.8 14.3 14.8 15.4 16.0 16.6 17.2 18.0 18.7 19.4 20.1 20.8 21.5 22.2 22.9 23.6 24.3 25.0 25.8 26.6 27.4 28.3 29.2 30.1 31.0 32.0 33.0 34.0 35.1 36.2 37.3 38.4 39.5 40.6 41.8 43.0 44.2 45.4 46.6 47.8 49.0 50.2 51.5 52.9 64.3 55.7 57.1 58.6 60.1 61.8 63.5 65.3 67.2 69.1 71.0 72.9 74.9 76.9 79.1 81.3 83.5 85.8 88.2 90.6 93.0 95.6 98.3

0.5 7.2 7.7 8.2 8.7 9.2 9.7 10.2 10.7 11.2 11.8 12.3 12.8 13.3 13.8 14.3 14.9 15.5 16.1 16.7 17.3 18.0 18.7 19.4 20.1 20.8 21.5 22.2 22.9 23.6 24.3 25.1 25.9 26.7 27.5 28.4 29.3 30.2 31.1 32.1 33.1 34.2 35.3 36.4 37.5 38.6 39.7 40.8 41.9 43.1 44.3 45.5 46.7 47.9 49.1 50.4 51.7 53.0 54.4 55.8 57.3 58.8 60.3 62.0 63.7 65.5 67.4 69.3 71.2 73.1 75.1 77.2 79.3 81.5 83.8 86.1 88.4 90.8 93.3 95.8 98.6

0.6 7.3 7.8 8.3 8.8 9.3 9.8 10.3 10.8 11.3 11.9 12.4 12.9 13.4 13.9 14.4 14.9 15.6 16.2 16.8 17.4 18.1 18.8 19.5 20.2 20.9 21.6 22.3 23.0 23.7 24.4 25.2 26.0 26.8 27.6 28.4 29.3 30.2 31.2 32.2 33.2 34.3 35.4 36.5 37.6 38.7 39.8 40.9 42.0 43.2 44.4 45.6 46.8 48.0 49.2 50.5 51.8 53.1 54.5 55.9 67.4 58.9 60.5 62.1 63.9 65.7 67.5 69.4 71.3 73.3 75.3 77.4 79.5 81.7 84.0 86.3 88.6 91.0 93.5 96.1 98.9

0.7 7.3 7.8 8.3 8.8 9.3 9.8 10.3 10.8 11.3 11.9 12.4 12.9 13.4 13.9 14.4 15.0 15.6 16.2 16.8 17.4 18.2 18.9 19.6 20.3 21.0 21.7 22.4 23.1 23.8 24.5 25.3 26.1 26.9 27.7 28.5 29.4 30.3 31.3 32.3 33.3 34.4 35.5 36.6 37.7 38.8 39.9 41.0 42.1 43.3 44.5 45.7 46.9 48.1 49.3 50.6 51.9 53.3 54.7 56.1 67.6 59.1 60.6 62.3 64.1 65.9 67.7 69.6 71.5 73.5 75.5 77.6 79.7 81.9 84.2 86.5 88.9 91.3 93.8 96.4 99.2

0.8 7.4 7.9 8.4 8.9 9.4 9.9 10.4 10.9 11.4 12.0 12.5 13.0 13.5 14.0 14.5 18.1 15.7 16.3 16.9 17.5 18.3 19.0 19.7 20.4 21.1 21.8 22.5 23.2 23.9 24.6 25.3 26.1 26.9 27.7 28.6 29.5 30.4 31.4 32.4 33.4 34.5 35.6 36.7 37.8 38.9 40.0 41.1 42.3 43.5 44.7 45.9 47.1 48.3 49.5 50.7 52.0 53.4 54.8 56.2 57.7 59.2 60.8 62.5 64.2 66.0 67.9 69.8 71.7 73.7 75.7 77.8 80.0 82.2 84.4 86.7 89.1 91.5 94.0 96.7 99.4

0.9 7.4 7.9 8.4 8.9 9.4 9.9 10.4 10.9 11.5 12.0 12.5 13.0 13.5 14.0 14.5 15.1 15.7 16.3 16.9 17.6 18.3 19.0 19.7 20.4 21.1 21.8 22.5 23.2 23.9 24.6 25.4 26.2 27.0 27.8 28.7 29.6 30.5 31.5 32.5 33.5 34.6 35.7 36.8 37.9 39.0 40.1 41.2 42.4 43.6 44.8 46.0 47.2 48.4 49.6 50.9 52.2 53.6 55.0 56.4 57.9 59.4 60.9 62.6 64.4 66.2 68.1 70.0 71.9 73.9 76.9 78.0 80.2 82.4 84.7 87.0 89.4 91.8 94.3 96.9 99.7

1557

Gal.

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0

0.0 6.6 12.8 18 7 24:3 29.6 34 6 39:4 43 8 48'1 52:l 55.8 59.3 62.6 65.7 68.6 71 3 73:9 76 4 78:s 81.1 83.3 85.4 87 5 8915 91.4 93 3 95:l 96.8 98.4 100.0

1.3 7.8 14.0 19.9 25.3 30.6 35 5 4013 44 7 48'9 52:s 56.5 60.0 63.2 66.3 69.1 71.8 74.4 76 9 79:3 81.6 83.7 85.8 87 9 89:9 91.8 93 7 9514 97.1 98.7

0.7 7.2 13.4 19 3 2418 30.1 35 1 3918 44 2 48:5 52.5 56.1 59.7 62.9 66.0 68.9 71 6 74:l 76.6 79.0 81.3 83.5 85.6 87 7 89:7 91.6 93 5 95:3 97.0 98.6

2.0 8.4 14.6 20 4 25:9 31.1 36 0 40'7 45'1 49'3 53:2 56.8 60.3 63.5 66.6 69.4 72 1 7417 77 1 79:s 81.8 83.9 86.0 88 1 9O:l 92.0 93 9 9516 97.3 98.9

2.6 9.1 15.2 21 0 2614 31.6 36 5 4112 45 5 49'7 53:6 57.2 60.7 63.8 66.9 69.7 72 3 74:9 77 3 7917 82.0 84.1 86.2 88 3 90:3 92.2 94 0 95:s 97.4 99.0

3.3 9.7 15.8 21 5 26:s 32.1 37 0 4116 45 9 50'1 5319 57.5 61.0 64.1 67.1 69.9 72 6 7511 77.6 79.9 82.2 84.4 86.4 88 5 9015 92.4 94 2 96:O 97.6 99.2

3.9 10.3 16.4 22 1 27:4 32.6 37 5 42'0 46:4 50 5 5413 57.9 61.3 64.5 67.4 70.2 72 8 7514 77.8 80.2 82.4 84.6 86.7 88 7 90:7 92.5 94 4 96:l 97.8 99.3

4.6 11.0 17.0 22 7 2810 33.1 38 0 42'5 46:s 50 9 54:7 58.2 61.6 64.8 67.7 70.5 73 1 75:7 78 1 8014 82.6 84.8 86.9 88 9 90:s 92.7 94 6 96:3 97.9 99.5

5.3 11.6 17.6 23.2 28.5 33.6 38 4 42'9 47'2 51'3 55:l 58.6 62.0 65.1 68.0 70.8 73 4 75:9 78 3 8017 82.9 85.0 87.1 89 1 9110 92.9 94 8 96:5 98.1 99.7

5.9 12.2 18.1 23 8 29.1 34.1 38 9 43'4 47'7 51'7 5514 58.9 62.3 65.4 68.3 71.0 73 6 7611 78 6 80:9 83.1 85.2 87.3 89 3 9112 93.1 94 9 96:s 98.2 99.8

The chart developed as a result of this study is shown in Figure 3; the Hebl, Rendel, and Garton octane numbercompression ratio scale is retained as the Y axis, but a new tetraethyllead scale is used for the X axis. Tabular values for the Y-axis scale are given in Table I and for the X-axis scale in Table 11.

e5

5-

was associated with the warping of the lines of constant tetraethyllead addition and could be corrected by returning to the earlier chart form in which the lines of constant tetraethyllead addition were placed a t right angles to the lines of constant octane number. This change would also permit a simplification of thefmethod of evaluating lead response, as will be discussed below.

0'

I

0.OI

I

0.02

I

0.04

LAMP

I

l

l

1

I

0.10

0.20

a40

SULFUR-

I

l

l I.a

WT. %

FIGURE 4. PREDICTION OF LEAD RESPONSE (above) BY C. F. R. MOTORMETHOD AND (below)BY C. F. R. RESEARCH METHOD (1939)

I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY

1558

Vol. 33, No. 12

TABLE 111. COMPARISON OF OBSERVED AND PREDICTED CLEAROCTANENUMBERS yo Compn. of Blend A 100 95 90 75 50 0 B 100 95 90 75 50 C 100 95 90 75 50 A 95 90 75 50 0 B 95 90 75 50

D 0 5 10 25 50 100 D

Obsvd. 58.3 60.6

63.2 67.0 73.0 79.5 70.5 70.9 71.4 73.4 75.4

0

5 10 25 50 D 0 5 10 25 50 E 5 10 25 50 100 E 5 10 25 50

67.9 68.7 69.9 72.5 74.7 60.6

TABLE IV.

70Compn. of Blend

C. F. R. M. Octanes C.F. R. R. (1939) Octanes Predicted

..

Obsvd. 58.6 60.9 65.1 71.3 80.8 93.1

7i:3 71.8 73.4 75.9

79.2 80.8 82.2 86.1 88.3

66:s 62.3 66.6

72.8

69:l 69.9 72.1 75.5

Predicted

73.8 75.4 78.1 81.6 85.9 60.0

A C 95 90 75 50 A 95 90 75 50 0 B 95 90 75 50 C 95 90 75 50 G 0 25 50 75

6i:O 64.5 71.1 81.3

..

si):5 81.5 84.1 88.2 7i: 7 77.0 80.7 86.3

63.2 67.1 73.1 75.3

6317 66.7 73.0 75.3

63.0 71.6 80.8 91.4

Si:9 73.0 79.9 91.1

71.8 72.2 73.0 74.2

71.0 71.4 72.4 73.8

80.8 81.3 84.6 87.6

80.4 81.3 83.6 87.2

100

D E

C. F. R. M. Octanes .C. F. R. R. (1939) Octanes Obsvd. Predicted Obsvd. Predicted

5

10 25 50 F 5 10 25 50 100 F 5 10 25 50 F 5 10 25 50 H 100 75 50 25 0

69.1 70.6 72.6 74.6

69.0 69.5 71.2 73.7

75.4 76.5 80.0 85.3

75.6 76.9 80.2 85.5

62.0 64.2 70.6 78.8 82.9

62.0 64.2 69.9 78.5

..

60.9 64.7 73.4 85.4 98.4

62.7 65.5 73.2 85.1

71.1 72.2 75.3 78.3

71.7 72.6 75.1 78.8

81.0 82.4 87.2 91.9

81.1 82.4 86.1 91.8

69.6 70.4 74.2 78.2

69.7 71.0 74.1 79.0

77.5 78.3 83.6 89.9

76.1 77.7 82.4 89.5

69.7 76.2 81.6 86.2 91.6

7610 81.1 85.5

COMPARISON OF OBSERVED AND PREDICTED LEADED OCTANE NUMBERS BY

..

..

c. F. R.MOTORMETHOD

Octane Values

yo Compn. of Blend

A 100 95 90 75 50

0 B 100 95 90 75 50 C

100

95 90 75 50 A 95 90 75 60 0

B 95 90 75 50 C 95 90 75 50 A 95 90 75 50

D 0

5 10 25 50 100 D 0 5 10 25 50

D

0 5 10 25 50

E

5 10 25 50 100 E 6 10 25 50 E 6 10 25 50 D 5 10 25 50

0

100

B 95 90 75 50 C 95 90 75 50 G 0 25 50 75 100

F 5

c c ' T ' E ' L'

Octane Sensitivitya

Pre3icted

0.018 0.027 0.042 0.076

0.3 0.3 1.9 4.3 7.8 13.6

24.8 23.5 21.9 17.9 13.8 7.9

63.2 67.0 73.0 79.5

64.4 66.3 68.1 72.4 77.5 81.3

65.1 67.0 68.8 71.4 76.2 81.0

70.0 71.3 73.0 76.0 79.7 82.2

69.9 71.3 72.9 74.7 78.4 82.2

75.8 77.1 78.5 80.2 82.2 83.3

75.8 76.8 77.8 78.5 81.1 83.5

79.9 80.9 81.0 82.2 83.4 84.0

79.1 79.8 80.2 80.8 82.7 84.4

0.085 0.084 0.086 0.084 0.085

8.7 9.9 10.8 12.7 12.9

11.5 10.5 9.9 8.6 8.4

70.6 70.9 71.4 73.4 75.4

73.7 74.6 75.4 76.8 78.5

73.3 73.5 73.8 75.4 77.2

75.8 76.1 76.8 78.5 79.7

75.4 75.4 75.6 76.8 78.6

78.1 78.7 79.2 79.7 81.0

77.8 77.6 77.5 78.6 80.2

79.4 80.0 80.3 80.8 81.8

79.3 79.0 79.0 79.7 81.2

0.054 0.054 0.057

14.8 14.2 13.0

0.063

5.9 6.7 8.2 9.1 11.2

67.9 68.7 69.9 72.5 74.7

72.3 73.7 73.8 75.0 77.6

71.6 72.2 73.2 75.2 76.9

74.3 75.8 76.0 77.1 79.2

74.5 74.8 75.4 77.2 78.5

77.8 78.6 78.9 79.9 81.0

77.5 77.8 78.1 79.5 80.4

79.8 80.5 80.5 80.5 82.2

79.4 79.6 79.8 81.0 81.7

0.091 0.164 0.407 0.847 1.485

-0.6 -0.2 4.5 7.7 16.1

17.5 15.8

60.6

65.4

0.157 0.228 0.452 0.877

Lamp Sulfur,

70

0.011

0.016

0.066

4 M b

11.6

10.0

gal.,

obsvd. 58.3

60.6

0.5 08. T. E. L./gal. Obsvd. Predicted

1.0 cc. T. E. L./gal. Obsvd. Predicted

2.0 cc. T. E. L./gal. Obsvd. Predicted

3.0 cc. T. E. L./gal. Obsvd. Predicted

7.3 3.4

63.2 67.1 73.1 75.3

70.1 74.5 76.0

65.4 67.4 69.7 74.8

76.1

68.6 69.1 73.0 75.7 76.5

68.8 70.3 71.7 76.1 76.6

72.6 73.0 75.0 76.9 77.2

73.0 74.2 74.2 77.6 77.4

75.3 75.4 76.8 78.2 77.8

75.6 76.4 75.8 78.6 77.8

9.0 9.1 11.6 13.4

10.0 9.2 6.9 5.2

71.8 72.2 73.0 74.2

74.4 74.6 75.0 76.7

74.3 74.4 74.6 76.4

76.3 76.5 76.8 76.8

76.0 76.0 75.8 76.3

78.1 77.8 77.8 77.7

78.1 77.9 77.3 77.3

78.9 78.6 78.6 78.7

79.4 79.1 78.2 78.1

0.123 0.191 0.406 0.814

6.3 5.9 7.4 10.7

12.4 11.1 9.0 6.3

69.1 70.6 72.6 74.6

72.2 72.7 74.1 75.9

72.2 73.3 74.8 76.1

74.6 74.6 75.1 76.8

74.4 75.3 76.3 77.1

77.7 77.2 77.5 78.3

77.2 77.6 78.2 78.3

78.9 78.6 78.7 78.8

78.8 79.1 79.3 79.2

0.014 0.018 0.026 0.041

-1.1 0.5 2.8

25.2 22.8 19.5 14.8 6.5

62.0 64.2 70.6 78.8 82.9

67.2 69.9 75.3 81.2 83.7

68.7 70.1 75.3 81.7 84.0

72.1 73.8 79.4 82.4 84.5

73.3 74.3 78.5 83.6 84.8

77.2 78.5 82.2 84.0 85.2

78.8 79.1 82.2 86.0 86.8

80.7 81.5 83.7 85.6 85.8

82.0 82.0 84.3 87.4 86.4

74.2 75.0 77.3 80.2

73.7 74.6 77.4 79.8

76.1 76.9 78.9 81.2

75.5 76.4 78.8 81.0

78.3 78.8 80.7 82.5

77.8 78.6 80.6 82.4

79.6 80.1 81.6 83.5

79.2 79.8 81.8 83.4

73.2 74.2 76.3 80.8

72.8 73.8 76.9 80.2

75.0 76.0 78.5 81.4

75.2 76.1 78.8 81.7

78.6 79.3 80.5 83.0

78.0 79.5 81.2 83.4

80.2 81.0 82.0 84.0

79.7 80.5 82.5 84.4

75.0 80.9 85.6 91.6 97.2

75.7 81.4 86.0 90.4 95.3

79.4 84.2 89.6 94.1

83.0 88.4 93.2 98.9

84.0 88.5 92.8 96.8

85.2 90.5 94.6

86.6 90.9 95.0

0.066

6.6

15.5

10.6

10.6 71.1 0.087 9.9 10.3 72.2 10.2 0.086 10 75.3 9.3 11.9 0.075 25 7.9 78.3 13.6 0.078 50 F 13.2 69.6 0.051 7.9 5 70.4 13.4 7.9 0.049 10 12.0 74.2 0.048 9.3 25 78.2 11.7 10.0 0.050 50 H 24.9 69.7 100 0.005 76.2 25.4 75 0.005 26.7 81.6 0.006 50 86.2 28.0 25 0.007 28.5 91.6 0.004 0 0 C.F. R. Research (1939) octane less-C. F. R. Motor octane. 5 From Figure 4 (upper graph).

66.6

a .

..

..

..

..

..

'

INDUSTRIAL AND ENGINEERING CHEMISTRY

December, 1941 TABLE v.

COMPARISON OF OBSERVED AND PREDICTED

LEADEDOCTANE NUMBERS BY 1 . 0 c c . T. E. L . / g d . Obsvd. Predicted

'7 Compn. Ef Blend

A

D

100 95 90 75 50 0 B 100 95 90 75 50

0 5 10 25 50 100

C

D

0 5 10 25 50 0 5 10 25 50

A

E

0

2.0 cc. T.E.L./gal. Obsvd. Predicted

3.0 CC. T.E. L./gal. Obsvd. Predicted

24.0 23.4 22.8 21.3 19.7 13.5

58.6 60.9 65.1 71.3 80.8 93.1

64.4 67.4 71.3 77.5 B5.8 94.7

65.1 67.2 70.8 76.3 84.2 94.8

69 0 72.3 74.3 80.2 88.1 95.6

69 8 71.6 75.1 79.7 86.8 96.1

74.9 77.7 79.2 83.9 89.9 96.3

75.5 76.9 79.8 83.5 89.6 97.7

78.6 80.7 81.9 85.4 91.8 97.4

78.8 80.0 82.5 85.8 91 3 98.7

17.9 17.1 16.5 14.5 14.1

79.2 80.8 82 2 86 1 88 3

83.6 84.4 85.4 87 3 96:1

82.6 83.8 84.9 88.3 90.4

86.1 86.1 87 2 89.2 91.0

84.8 85.9 86.9 90.0 91.8

88.6 89.1 89.4 91.0 93.0

87.6 88.5 89.3 92.0 93.6

90.1 90 3 90.8 92 0 93.8

89.3 90.1 90 8 93.2 94.8

19 8 19.5 19.0 18 0 16.5

73.8 75.4 78.1 81.6 85.9

78.4 79.6 81.2 83.8 89.1

78 2 79.4 81.8 84.6 88.4

81.5 83.4 84.3 86 8 90.5

81.2 82.4 84.3 86.8 90.3

85.2 85.5 86.6 89.9 92.5

84.6 85.4 87.2 89.5 92.5

87.1 87 2 88.0 90 4 93.5

86.5 87 4 89.0 91.2 93.9

20.5 19 4 16.5 14 2 5.1

60.0 63.0 71.6 80 8 91.4

65.1 67.2 74.0 83.2 92.6

65.4 68.1 75.5 83.4 92.1

69.6 70.3 76.1 84.6 92.8

69.5 71.8 78.2 85.1 92.7

73.8 73.8 79.6 86.7 93.2

74.4 76.2 81.4 87.2 93.2

77.0 77.5 81.6 88 3 93.8

77.3 78.8 83.3 88 6 93 7

16 7 15 9 12.8 9.6

80.8 81.3 84.6 87 6

84.4 84.7 86.5 89.3

83.7 84.0 86.6 89.0

86.2 86.4 87.9 90.3

85.8 86.0 88.2 90.1

88.4 88.6 89.3 91.3

88.3 88.4 90.0 91.4

89.8 89 9 90 5 92.2

89.9 89.9 91.2 92.2

18 2 16.9 15.0 12 2

75.4 76 5 80.0 85.3

78 8 80.0 83.3 87.2

79.2 80.0 82.8 87.2

81.6 82.0 84.8 88.9

82.0 82.4 84.6 88.6

85.4 85.6 87.6 90.3

85.0 85.2 87.0 90.4

87.5 87 8 88.9 91.6

86.8 86.8 88.4 91.4

23 9 23.1 21 9 20.3 10.7

6p.9 64 7 73.4 85.4 98.4

89'.2 78 8 89.1 99.8

67.2 70.6 78 2 88.6 99.6

71.3 73.2 82.4 91.1

71.8 74.8 81.6 90.8

77.6 79.8 85.4 94.3

77.2 79.6 85.2 93.5

81.0 81 8 87.2 95 1

80.3 82.4 87.4 95 2

17 3 17.0 15.6 13.5

81 0 82.4 87.2 91.9

84 4 85.7 89.8 94-6

84.0 85.2 89.6 93.7

87.9 88.6 91.5 95.6

86.1 87.2 91.2 95.0

89.4 90.6 93.1 97.2

88.7 89.8 93.2 96.7

91.1 91.9 94.4 98.0

90.4 91.3 94.6 97.7

20.4 19.4 18.6 16.5

77.5 78.3 83.5 89.9

81.4 81.9 87.3 93.4

81.6 82.0 86.4 92.2

83.6 85.4 89.9 94.9

84.2 84.6 88.6 93.8

86.6 87.8 91.9 96.5

87.4 87.5 91.3 95.9

88.3 89.7 93.9 97.4

89.4 89.4 92.8 97.2

5 10 25 50 100

B

E *

95 90 75 50

5 10 25 50

C

E

95 90 75 50

5 10 25 50

A

F

95 90 75 50

5 10 25 50 100

0

F

B 95 90 75 60

5 10 25 50

C

F

95 90 75 60

a

c. R. R. RESEARCH (1939) METHOD

D

100 95 90 75 50 95 90 75 50

1559

5 10 25 50

'

..

..

..

'

I

..

..

..

From Figure 4.

I n measuring the tetraethyllead response or lead susceptibility from this chart, it has been found convenient to define lead response or susceptibility as the slope of the line (dY/dX) on the chart. Since the X values given in Table I1 range from 0 at 0 cc. tetraethyllead per gallon to 1.0 a t 3.0 cc., this slope is numerically equal to the difference in Y value between 0 and 3 cc. tetraethyllead per gallon, or mathematically, dY ys--yo YS - Yo lead response, + ax - xs 1 -xo

-

.p

The evaluation of 4 is illustrated in the following example: T. E. L. Added, Cc./Gal.

0 2.0 3.0

'

Octane No. 67.9 77.7 79.8

X (Table 11)

Y (Table I)

0.0 0.811 1.00

42.4 54.7 57.7

54'7 - 42'4 = 15.2 (for the 0- and 2-co. values) 0.811 - 0.0 57.7 42.4 = 15.3(for the 0- and 3-02. values) or+ = 1.0 - 0.0

-

When relatively unreliable data are used or when a number of leaded octane values are available, it is sometimes desirable to plot the data points on the chart and establish the best average line graphically.

Prediction of Lead Response As pointed out by Graves (1) the response of the octane number of gasolines to the addition of tetraethyllead is dependent on the sulfur content and on the character of the gasoline used. Although the nature of the sulfur compound present is a factor of some importance in determining its effect on lead response, it has been found for merchantable gasolines which are substantially free of mercaptans and elementary sulfur that the effect on lead response can be satisfactorily correlated logarithmically with the 'sulfur content as determined by the A. S. T. M. lamp method. It has also been found that the character of the gasoline can be satisfactorily measured by the octane sensitivity or the difference between the C. F. R. Research method (1939) octane number and the C. F. R. Motor method or A. S. T. M. octane number. Figure 4 shows relations of this type which have been developed for the C.F. R. Motgrior A. S. T. M. method and for the C. F. R. Research method] (1939) octane values. I n predicting the lead response of a blend of two or more gasolines, values may be read directly from the upper or lower curves of Figure 4,using the volumetric average sulfur contont calculated for the blend and the octane sensitivity calculated for the unleaded blend as described above. Since octane sensitivity is not an additive property, this

PHYSICAL TESTSON STOCKS USED

TABLE VI. Stock Gravity A. P. I. Reid vabor pressure, lb./ss. in. Lamp sulfur, wt. % Aniline point, F. Acid heat value, O F. A. 8, T . M. distillation, Initial 5 % over 10%

50%

_ .

yo recovered

Vol. 33, No. 12

INDUSTRIAL AND ENGINEERING CHEMISTRY

1560

O

A 65.0

B 56.6

C 59.4

8.5 0.011 135 8

6.8 0.085 90 130

105 134 149 175 194 209 225

109 135 151 179 205 227 249 269 291 318 351 378 401 98.0

D 56.4

E 62.1

F 63.6

G 66.5

H 71.8

9.9 12.0 5.2 7.6 0.054 0.076 1.485 0.066 120 69 101 106 82 203 219 170

6.4 0.005 128 3

7.3 0.004 165 3

105 133 149 176 199 220

118 141 151 166 176 185 2 3 201 209 224 236 256 283 98.0

104 138 156 186 202 214

F.

239 253 273 303 329 355 98.0

E

255 275 298 339 368 393 98.0

92 118 132 164 194 224

250

282 312 344 380 400 402 96.0

125 172 187 203 215 228

240

256 274 291 325 361 399 98.0

98 138 166 217 233 242

251 263 284 346 400

4'3'0 94.0

method is preferred over an alternative method in which the values of lead susceptibility are read for each constituent a t their respective sensitivities and a t the volumetric average sulfur content, and then averaged to obtain the final value. This latter method is sometimes more convenient, however, and can be safely used if the differences in sensitivity are small. Comparisons of observed C. F. R. Motor and C. F. R. gasolines with Research (1939) Octane data On values predicted by Figure 2 are shown in Table 111. Similar

220 224 230 236 246 250 302 98.0

comparisons for leaded octane values are given in Tables IV and V in which the predicted octanes are based on 4 values read from Figure 4 and on the observed clear octanes prior to lead addition. Physical tests on the various stocks are given in Table VI. These tabulations average deviations of about 0.5 and maximum deviations of about 1.5 octane numbers. It should be borne in mind that although a wide variety of gasoline types has been studied, the relations shown are strictly empirical and due caution should therefore be exercised in the application of these correlations to new or unusual gasoline types.

Acknowledgments I

The writer wishes to acknowledge the assistance of Howard Wilson and E. M. Barber in the development of the octane blending relations, and of G. J. Goddard and N. B. Haskell in the development of the lead response relations,

Literature Cited CHEM., 31,850 (1939). Graves, IND. ( 2 ) Hebl. Rendel. and Garton. J . Inst. PetroZeurn Tech.. 18. 187 (1932); I I D . ENO.CHEM., 31,865 (1939). (3) Lovell, Campbell, and Boyd, Ibid., 26, 1105 (1934).

PRESENTED before the Division of Petroleum Chemistry at the 102nd Meeting of the American Chemical ~ o c i e t y , ' ~ t i a n tcity, i c N. J.

CALCIUM METAPHOSPHATE Rate of Reaction of Phosphorus Pentoxide

with Rock Phosphate G. L. FREAR AND L. H. HULL Tennessee Valley Authority, Wilson Dam, Ala.

HE process and equipment used in the manufacture of fertilizer-grade calcium metaphosphate by the Tennessee Valley Authority were described in previous publications (1, 2 ) . The experiments comprising the present work included measurements of the rate of absorption of phosphorus pentoxide vapor in hot rock phosphate as influenced by the temperature, phosphorus pentoxide concentration in the gas, velocity of gas, grade of rock phosphate, and presence of water vapor. The method of measurement consisted in exposing previously calcined test pieces, which had been compacted from finely ground rock phosphate, to atmospheres containing phosphorus pentoxide and in determining the weights gained by the test pieces in different periods of exposure under controlled conditions.

T

Materials The phosphorus pentoxide was generated within the apparatus by burning wi.th cylinder-grade oxygen the phosphorus vapor obtained by saturating oxygen-free nitrogen with high-grade yellow phosphorus.

The rock phosphate used as absorbent in most of the experiments was prepared by crushing several large lumps of Tennessee brown rock. The fluorapatite mas a high-grade Canadian mineral, the phosphatic matrix was from Tennessee, and the calcium oxide was National Formulary grade. The composition of the phosphatic absorbing materials, all of which were -150 mesh, is given in Table I as corrected for ignition loss a t 1100" C.

Equipment The principal elements of the apparatus were the means for generating P205*, the absorption chamber, the P20ssampler, and the means for disposal of the exit gas. Phosphorus pentoxide was absorbed by the material under study in the tube assembly shown in Figure 1. The mullite absorption tube, of 4.3-cm. inside diameter and 70-cm. length, was drilled through the side a t a point near its center; this

* Pi05 is used throughout this paper as the simplest formula for the oxide of pentavalent phosphorus and is not intended t o represent any particular

molecular species.