Reviewer 2, comment 1.1: lower Tr limit, PR, reviewer believes the text is misleading

[mostafa-razavi]

1.1 There is no reason that coexistence calculations must extend to a reduced temperature of 0.45 only. The industrial needs extend over the whole liquid-vapor coexistence curve down to the triple point and this may be down to Tr=0.30 for many compounds (eg isooctane, toluene, heavy iso-alkanes,… ). The Peng-Robinson EOS loses accuracy between Tr=0.3 and Tr=0.45. The current text is misleading. The text must indicate that prediction methods are required down to Tr=0.3 and that the PR EOS is not accurate in the range Tr=0.3 to 0.45.

Response:

We agree with the reviewer that coexistence calculation should ideally cover the entire temperature range, not only down to Tr=0.45. Therefore, the current text is stating that the entire temperature range from triple point to critical point is desired. However, it is not quite clear to the authors why the reviewer finds the current text misleading. The choice of Tr=0.45 as the lowest reduced temperature is rather arbitrary and mainly for the sake of consistency. We believe that this paragraph does not imply that the temperature range between triple point and Tr=0.45 is less important, therefore we did not modify the current text.

Any suggestion to improve this response?

[ramess101]

@mostafa-razavi

I would just add a parenthetical clause stating how low some triple points are:

"common methods for industrial applications treat the temperature range from triple point (which may be as low as Tr=0.3) to the critical point."

This way you satisfy some of the reviewers demands without modifying the whole manuscript for the 0.3 value.