[Paleopsych] depolymerization doubts (energy future)

[Lynn D. Johnson, Ph.D.]

This depends on how this demo project in Missouri goes. They are 
supposed to be converting turkey guts to light crude oil, but I can't 
find actual results. There may be some propriatary info about the 
process they don't tell, and as my brother says, there isn't enough info 
to really piece together what they are doing. Interesting, and certainly 
attractive. Will it work? No data yet.
Lynn

Steve wrote:

>In essence, no quick fix?
>
>Steve Hovland
>www.stevehovland.net
>
>-----Original Message-----
>From:	Lynn D. Johnson, Ph.D. [SMTP:ljohnson at solution-consulting.com]
>Sent:	Sunday, August 08, 2004 4:31 PM
>To:	The new improved paleopsych list
>Subject:	[Paleopsych] depolymerization doubts (energy future)
>
>My smart brother (prof, chem engineering, expert in mathematical 
>modeling of chemical processes) says the following about thermal 
>depolymerization in regards to the Discover article:
>
>Dear Lynn, 
>
>Sorry for the slow reply. I've been busy trying to finish sections of the 
>book I'm working on. 
>
>I just read the article you attached and read some (not all) the comments 
>on the web pages. 
>
>Random thoughts:
>Depolymerization is indeed possible and has been performed on different 
>materials for a long time.
>
>Breaking chemical bonds takes a fixed amount of energy. You can't cheat 
>thermodynamics (at least you can't and get an A in my class). Therefore, I 
>doubt the claim of 85% efficiency. I do not see how that can possibly be 
>close to the correct number. The process they describe requires a good 
>deal of mechanical and thermal energy. Even if you put water in (as they 
>claim about making water your friend) then you still have to provide about 
>350 kJ/mol of energy to break a carbon-carbon bond. Hence, I can't see how 
>you could get 85% efficiency. Maybe I'm wrong, but it would mean that you 
>are only breaking about 15% of the bonds in the material that you are 
>depolymerizing. That seems unlikely to produce "pure oil" as claimed. 
>
>Could it work? Yes. Does it work as advertised? I doubt it. Maybe I'm 
>wrong. There's really not enough information there to analyze the process. 
>
>Water at high temperature and high pressure has been used to degrade 
>organics before, but typically they use supercritical or near-critical 
>water. This does not mean water that nags you to pick up your socks, but 
>water that is near 650 K = 377 C = 710 F and 220 bar = 3200 PSI. Their 
>process is at 500 F and 600 PSI. Still, I think you could do some fairly 
>aggressive chemistry at those conditions that would require higher 
>temperatures otherwise. 
>
>The other thing that bothers me is this claim:
>Dehydration via depressurization is far cheaper in terms of energy 
>consumed than is heating and boiling off the water, particularly because 
>no heat is wasted.
>
>The fact is that it still costs energy to vaporize water. If you have to 
>vaporize 1 kg of water it will take you about 2000 kJ, no matter how you 
>do it. The heat of vaporization changes as a function of temperature, 
>decreasing at higher temperatures. However, I don't see any way to cheat 
>thermodynamics. 
>
>If you don't vaporize the water, but instead separate it in a two-phase 
>separator then you can do the separation for much less energy. I.e., you 
>rely on the fact that oil and water don't mix and take the oil off the top 
>of a gravitational separator or cyclone separator. 
>
>End random thoughts. 
>
>
>
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