Viscosity/temperature equations for coal tar pitches and refined tars

Abstract

The viscosities of eighteen tar products ranging from refined tar of 34° equiviscous temperature to electrode binder pitch of 102° softening point (Ring Ball) have been measured between wide temperature limits and within the viscosity range of 10 to 1010 centipoises. The applicability of three equation forms to these results has been assessed. A simple logarithmic relationship in terms of Fahrenheit temperature is satisfactory for most products at viscosities greater than 104 centipoises, but does not apply at lower viscosities or to the harder pitches. A double logarithmic viscosity/temperature relationship fits the results well, except those relating to the hard pitches, but it is insensitive and unreliable at viscosities of about 109 centipoises and greater. A third equation relating the logarithm of viscosity to the fifth power of absolute temperature has been shown to apply over the full range of materials, temperatures and viscosities examined. The significance of the constants used in these equations is discussed with respect to their value in comparing the temperature susceptibility of tar products. It is shown that the correct order of viscosity of a tar product, within the range of materials and viscosities investigated, can be predicted from its softening point or equiviscous temperature and its toluene‐insoluble content.

Experimental determination of chemical diffusion within secondary organic aerosol particles

“…A viscosity of B10 8 Pa s, for fresh SOA, is equivalent to that of tars, 25,30,34,35 and the substance would normally be considered to be semisolid. Again, this is entirely consistent with the recent experiments by several research groups, 14,[18][19][20][21]23,26 who, based on entirely different types of experiments, conclude that SOA is an amorphous solid or semisolid.…”

Temperature‐ and Humidity‐Dependent Phase States of Secondary Organic Aerosols

“…Gray filled circles and dashed lines are data/Vogel-Fulcher-Tammann fits from the literature (tabulated in the supporting information). (a) α-pinene-derived SOA; (b) five SOAs, including three measurements for Δ 3 -carene-derived SOA, compared to other substances (Diamante & Lan, 2014;Wood & Downer, 1965;Yanniotis et al, 2006). Colors match side illustrations showing precursor structures.…”

Coal Tar Viscosity when Dissolving Coke Oven Gas Deposits

“…The temperature dependence of the coal tar viscosity can be estimated by the Walter equation in logarithmic form [6], which is included in the methodology for viscosity determining on ASTM D341: …”

“…Equation of Cornelissen-Waterman is used to assess, in particular, the rheological properties of coal tar pitch and coal tar [6]:…”

“…It is known that the constants K 2 in the modified Walter Equation and B in the Cornelissen-Waterman equations are the measure of the temperature dependence regardless to the liquid level of viscosity [6].…”