Question

How to calculate molar average viscosity of hydrocarbon mixture?

Answer 1

The viscosity of gas mixtures at one atmosphere and reservoir temperature can either be read from Fig. 2 or determined from the gas-mixture composition with Eq. 1.

RTENOTITLE....................(1)

where:

μga = viscosity of the gas mixture at the desired temperature and atmospheric pressure

yi = mole fraction of the ith component

μi = viscosity of the ith component of the gas mixture at the desired temperature and atmospheric pressure (obtained from Fig. 1)

Mgi = molecular weight of the ith component of the gas mixture

N = number of components in the gas mixture.

This viscosity is then multiplied by the viscosity ratio (from Fig. 3 or Fig. 4) to obtain the viscosity at reservoir temperature and pressure.