Fluid Viscosity of light hydrocarbons 2

[Timmigrant]

I'm currently trying to establish the fluid viscosity of a mixed gas. Within the mixed gas is hydrogen, methane, ethane, propane and butane. In order to do that I need the individual viscosities at my process temperature and pressure. I've found a neat formula using Sutherland's Constants to determine each viscosity, however I'm having troubles finding the Sutherland's Constants for the hydrocarbons. Does anyone have either a another method of determining the fluid viscosity, or a source for the Sutherland's Constants for methane, ethane, propane and butane?

 

[TD2K]

ln viscosity is proportional to 1/T where T is the absolute temperature.

This is some data from "The Properties of Gas and Liquids" by Reid, Prausnitz and Sherwood, 3rd edition

methane

20 deg C, 109 micropoise
100 deg C, 133 micropoise
200 deg C, 160 micropoise
300 deg C, 185 micropoise

ethane

20 deg C, 90.1 micropoise
50 deg C, 99.8 micropoise
100 deg C, 114 micropoise
250 deg C, 153 micropoise

propane

20 deg C, 80.6 micropoise
60 deg C, 92.2 micropoise
125 deg C, 107 micropoise
200 deg C, 125 micropoise
275 deg C, 142 micropoise

n-butane

20 deg C, 73.9 micropoise
60 deg C, 83.9 micropoise
120 deg C, 99.8 micropoise

i-butane is very similar to n-butane's viscosities

 

[25362]

The requested properties at various T,P are tabulated by the Nist webbook.

Look for

http://webbook.nist.gov/chemistry/

for each of the above hydrocarbons, after you submit its name, hit the fluid properties heading. Good luck.

 

[mbeychok]

Timmigrant:

If I read your posting correctly, you want to know how to calculate the viscosity of a gas mixture at a given temperature and pressure.

The book "Data Book on Hydrocarbons" written by J.B. Maxwell and published by D. Van Nostrand in 1950 has this formula for calculating the viscosity of a gas mixture at atmospheric pressure and at a given temperature:

Zm = A/B
A = the summation of (Ni)(Zi)(Mi)^0.5 for each component
B = the summation of (Ni)(Mi)^0.5 for each component

where:
Zm = viscosity of the gas mixture
Ni = mole fraction of each gas component
Zi = viscosity of each gas component
Mi = molecular weight of each component

That same book also has a graph for use in converting atmospheric pressure viscosities to higher pressure viscosities. The graph is a plot of (Zp)/(Za) versus the reduced pressure of the gas (Pr), where:

Zp = the higher pressure viscosity
Za = the atmospheric pressure viscosity
Pr = (the higher pressure)/(critical pressure of the gas)

 

[mbeychok]

Timmigrant:

If you need further information regarding "Data Book on Hydrocarbons", you can contact me at my web site (see below).

Milton Beychok
(Contact me at www.air-dispersion.com)

 

[TangoCleveland]

There are several used copies of "Data Book on Hydrocarbons: Application to Process Engineering" by J. B. Maxwell on Amazon.com, as well as a new 1975 reprint. I like the volume because the graphs let you SEE how properties change with temperature, pressure, etc.

Larry