6 replies to this topic

[populas]

Hello,

I am looking for the specific heat of naphta (C10H8) at around 20°C. Unlike many researches on some good chemical books, even in google, I failed to find a reliable value (or formula). Actually yes, I found in the Perry this : 0,402 cal/(g.°C) at 87,5°C. But what about 20°C (up to 60°C)?

Can anybody help me? A reference or a table would be highly appreciated.

Thank you in advance.

[MrShorty]

DIPPR's database and/or Prausnitz et al's The Properties of Gases and Liquids will have equations for the heat capacity as a function of temperature. I generally prefer DIPPR because they will better document what data they used in regressing the equation which leads to a better idea of how reliable the value is.

[kkala]

Indeed expression in Perry (7th edition) is for temperatures between 80.3 and 218 oC, with 0.403 cal/g/oC at 80.3 oC.
DDBST at http://ddbonline.ddb...8cP%29%29.shtml can give an answer, presenting heat capacities of solid or liquid naphthalene at several temperatures. You can start from measurements by Southard & Brickwedde (1933).

Edited by kkala, 28 October 2011 - 12:11 PM.

[breizh]

http://infosys.korea.../kdb/index.html

Let you try this resource , it should help .
Are you talking Liquid , Gas or Solid form ?

Go to Hydrocarbon , pure properties and type the chemical formula and you will get all the properties you need

Breizh

Edited by breizh, 29 October 2011 - 01:16 AM.

[populas]

Thank you all for your help.

Something is fishy. I have been told the feed is Naphtha (liquid), but by visitng all your links/references, it seems naphtha is liquid from 80°C! And the problem here is that the liquid feed is in a range of 20 to 50°C. I guess I should conclude that the feed is not naphtha (at least not a pure one)?

Again, thank you!

regards

[MrShorty]

I guess I should conclude that the feed is not naphtha (at least not a pure one)?

Either that, or you are misunderstanding the term "naphtha." When you put the molecular formula C10H8 in your original post, we all assumed you meant the pure compound "naphthalene," which, as you noted, has a melting point ~80 C.

The term "naphtha," in its most general sense, refers to any mixture of hydrocarbons (I've seen gasoline referred to as a naphtha). So, it would seem the most important first step in answering your question is to decide what is meant by "naphtha" in your context, and any other information you can get about the naphtha in question (composition, boiling point/boiling point range, MW, etc.).

[kkala]

I agree with MrShorty. Most probably you refer to naphtha, not to naphthalene, especially if mentioned "naphta" is a refinery product.
Note. Info about naphtha and naphthalene in wikipedia indicates that : naphthalene production in refineries is not usual today, contrary to naphtha; name of naphthalene came from what was called naphtha in ~ 1821.
Freezing point of naphthaline=80.3 oC, versus -30 oC for naphtha or less.
It seems rather easy to identify the mentioned "naptha" liquid. If the "liquid feed" goes to a catalytic reforming or desulfurization unit, this indicates refinery naphtha.

Edited by kkala, 09 November 2011 - 04:59 PM.