Viscosity Charts

Unfortunately, there are very few experimental measurements for the viscosity of hydrogen sulfide. A review of the available data is presented in the appendix of this chapter. However, from the few data available and by applying the principle of corresponding states to the viscosity, a chart for the viscosity of H2S was constructed. The resulting plot is shown in figure 2.6. Details of this new correlation are also in the appendix to this chapter. 

There are a couple of things of interest from these two charts. In the liquid phase the viscosity decreases with increasing temperature - which tends to be the common experience. On the other hand, in the gas phase the viscosity increases with increasing temperature. This was demonstrated earlier at low pressure and reaffirmed by the behavior shown in the new plots. Furthermore, these charts show the viscosity of the acid gas components over a rather wide range of pressure and temperature, and yet the viscosity only varies by about an order of magnitude (from about 0.02 to 0.2 mPa-s). 

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The viscosity of ttie liquid may reduce the velocity and capacity enough to require a larger orifice size than the usual liquid capacity equation would indicate This simplified viscosity chart and the Kj viscoscorrection factors obtainable from i( are for use m properly sizing relief valves intended for viscous liquid ser vice. Equations and graphs used m prepanng this chart reflect conservative engmeenng data on the subject... 

Figure 20. Temperature-viscosity chart indicating influence of sulfur contents in...

Using the reduced-viscosity chart (Fig. 3.3) and knowledge of the critical properties, develop an approximate temperature-dependent expression for the viscosity of air at atmospheric pressure and in a temperature range 300 [Pg.136]

How to determine any HC liquid viscosity. For the viscosity of most any HC, see Fig. A-3 in Crane Technical Paper No. 410 [3], If your particular liquid is not given in this viscosity chart and you have only one viscosity reading, then locate this point and draw a curve of cP vs. temperature, °F, parallel to the other curves. This is a very useful technique. I have found it to be the more reliable, even when compared to today s most expensive process simulation program. Furthermore, I find it to be a valuable check of suspected errors in laboratory viscosity tests. If you don t have the Crane tech paper (available in any technical book store), then get one. You need it. I have found that most every process engineer I have met in my journeys to the four corners of the earth has one on their bookshelf, and it always looks very used. 

Estimate the viscosity of a mixture described in the table below at T = 330 K and P = 25 atm using the reduced viscosity chart in Figure 2.4 ... 

This correlation was used to generate the viscosity chart for pure H2S which is shown in figure 2.6. Furthermore it has been implemented in AQUAlibrium and used for many acid gas projects. 

The Wright method, as illustrated in Fig. 4-45, utilizes the standard ASTM viscosity chart but in a way different from the method recom-... 

A chart by J. Groff relates the SAE grades, the kinematic viscosity, and the viscosity indices. This correlation is given in Figure 6.1 in the 1994 edition. 

The viscosity of a hydrocarbon mixture, as with all liquids, decreases when the temperature increases. The way in which lubricant viscosities vary with temperature is quite complex and, in fact, charts proposed by ASTM D 341 or by Groff (1961) (Figure 6.1) are used that provide a method to find the viscosity index for any lubricant system. Remember that a high viscosity index corresponds to small variation of viscosity between the low and high... 

Viscosity—Temperature. Oil viscosity decreases with increa sing temperature in the general pattern shown in Eigure 8, an example of ASTM charts which are available in pad form (ASTM D341). A straight line drawn through viscosities of an oil at any two temperatures permits estimation of viscosity at any other temperature, down to just above the cloud point. Such a straight line relates kinematic viscosity V in mm /s(= cSt) to absolute temperature T (K) by the Walther equation. 

Although the viscosity index is useful for characterizing petroleum oils, other viscosity—temperature parameters are employed periodically. Viscosity temperature coefficients (VTCs) give the fractional drop in viscosity as temperature increases from 40 to 100°C and is useful in characterizing behavior of siHcones and some other synthetics. With petroleum base stocks, VTC tends to remain constant as increasing amounts of VI improvers are added. Constant B in equation 9, the slope of the line on the ASTM viscosity—temperature chart, also describes viscosity variation with temperature. 

Some quite viscous oils in the 450 650 mm /s are employed for high temperatures. Less viscous oils, down to 25 mm /s and lower at 40°C, are used in special greases for low temperatures. The maximum oil viscosity in a grease for starting medium torque equipment is about 100, 000 mm /s(= cSt) (4). Extrapolations for various oils can be made on viscosity—temperature charts, as shown in Figure 8, to estimate this approximate low temperature limit. 

In most cases it is sufficient to be able to convert from one viscometer value to another or to approximate kinematic viscosities with the help of charts or tables Hterature from manufacturers is useful. 

Fig. 4. An alkaH—gravity—viscosity (AGV) control chart for a 3.22-weight ratio sodium siHcate solution, where (—) and (----------- represent lines of constant...

Fig. 12. A viscosity-temperature chart, mm /s = cSt ----, iadustrial asphalts ---cutback asphalts ...

Saturation and superheat tables and a chart to 15,000 psia, 840 F appear in Stewart, R. B., R. T. Jacobsen, et al., Theimodynamic Propeities of Refiigerants, ASHRAE, Atlanta, GA, 1986 (521 pp.). For specific heat, thermal conductivity, and viscosity, see ASHRAE Theimophysical Propeiiies of Refiigerants, 1993. 

Saturation and superheat tables and a diagram to 300 bar, 580 K are given by Reynolds, W. C., Theimodynamic Propeities in S.I., Stanford Univ. pubL, 1979 (173 pp.). Saturation and superheat tables and a chart to 10,000 psia, 640 F appear in Stewart, R. B., R. T Jacobsen, et al., Theimodynamic Propeiiies of Refiigerants, ASHRAE, Atlanta, GA, 1986 (521 pp-)- For specific beat, thermal conductivity, and viscosity, see Theimophysical Propeiiies of Refiigerants, ASHRAE, 1993. The 1993 ASHRAE Handbook—Pundamentals (SI ed.) contains a thermodynamic diagram from 0.1 to 700 bar for temperatures to 600 K. 

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