B B2 4 Ac

C = n6t2 + n7t + n with t according to Eq. (29b). The coefficients ni of Eq. (30) are listed in Table 34.

Table 34. Numerical values of the coefficients of the dimensionless saturation equations, Eqs. (29) to (31)

i

i

ni

1

0.116 705 214 527 67 x 104

6

0.149 151 086 135 30 x 102

2

- 0.724 213 167 032 06 x 106

7

- 0.482 326 573 615 91 x 104

3

- 0.170 738 469 400 92 x 102

8

0.405 113 405 420 57 x 106

4

0.120 208 247 024 70 x 105

9

- 0.238 555 575 678 49

5

- 0.323 255 503 223 33 x 107

10

0.650 175 348 447 98 x 103

Equations (29) to (31) reproduce exactly the p-T values at the triple point according to Eq. (8), at the normal boiling point [12] and at the critical point according to Eqs. (2) and (3).

Equation (30) is valid along the entire vapor-liquid saturation line from the triple-point temperature Tt to the critical temperature Tc and can be simply extrapolated to 273.15 K so that it covers the temperature range

Computer-program verification

To assist the user in computer-program verification of Eq. (30), Table 35 contains test values for three selected temperatures.

Table 35. Saturation pressures calculated from Eq. (30) for selected values of Ta

T/K

ps / MPa

300

0.353 658 941 x

10-2

500

0.263 889 776 x

101

600

0.123 443 146 x

102

a It is recommended to verify the programmed equation using 8 byte real values for all three values of T given in this table.

a It is recommended to verify the programmed equation using 8 byte real values for all three values of T given in this table.

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