A = aromatics, volume %

G = gravity, API (American Petroleum Institute)

V = volatility: boiling point or average of Test Method D 86 10%, 50%, and 90% points, C.

To correct for the effect of the sulfur content of the fuel on the net heat of combustion, apply the following

equation:

Q = Qp x [1-0.01(S1)] + C(S1) (3)

Where:

Q = net heat of combustion, megajoules/kilogram or British thermal unit (BTU) per pound, of the fuel

containing S1 weight percent sulfur,

Qp = Qp1 (inch-pound units) or Qp2 (SI units),

S1 = sulfur content of the fuel, mass %, and

C = 0.10166 (SI units) or 43.7 (inch-pound units) = a constant based on the thermochemical data on

sulfur compounds.

The empirical equations for the estimated net heat of combustion, sulfur-free basis, were derived by stepwise

linear regression methods using data from 241 fuels, most of which conform to specifications for aviation

gasolines and aircraft turbine or jet engine fuels.

Calculate the net heat of combustion, sulfur-free basis, using equation No. 1. Round the value obtained to

the nearest one-thousandth.

Example:

Sample: Kerosene

Determined Values:

Aromatics, A= 12.5% volume

3

Density, D = 805.0 kg/m

Distillation

T10 = 203C

T50 = 233C

T90 = 245C

T= (203 + 233 + 245) / 3 = 227C

(4)

Calculated Value: A x T = 2837.5

(5)

Substitute into equation No. 2.

Qp2 = [5528.73 - 92.6499A = 10.1601(227)+ 0.314169 (2837.5)] / D + 0.0791707 (12.5) (2) -

0.00944893(227) - 0.000292178 (2837.5) + 35.9936

Therefore:

Qp2 = 43.4101015 = 43.410 MJ/kg, sulfur-free basis

Report the result to the nearest one-thousandth as net heat of combustion of the fuel in megajoules per

kilogram.

1-8

QM 5181

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