On Tue, 11 Sep 2007 22:03:31 -0700, Keith Hughes
wrote:

Water vapor - what you can actually see -

Water vapor is a gas and is invisible. Steam is the vapor phase of
water. Clouds are liquid water. The liquid is hundreds of times as
dense as the vapor, by the way.

On Wed, 12 Sep 2007 00:36:28 GMT, Jere Lull wrote:

TW, though I don't believe a small engine such as ours could
practically boil much water --that last degree to flash to steam is a
killer-- it seems a good idea to distill water drawn from the hot water
tank, gaining a good bit of the required BTUs for free.

A BTU is a British Thermal Unit. It is the ammount of heat that it
takes to raise one pound of water by one degree F. It takes about 1073
BTUs to evaporate a pound of water. Roughly 140 BTUs to raise the
water from room temperature to the boiling point. If you are heating
the water in the hot water tank for free, it would help, but not by
much.
There is not really a last degree. The phase change from liquid to gas
takes place at a constant temperature, the boiling point, and and the
last degree of heating below that point, is the same as any other
degree, one BTU per pound. In round figures, seven eights of the
energy goes into the evaporation, one eighth to temperature change.

Boiling point varies greatly with pressure, but I assume that we are
all talking about ordinary sea level, 14.7 psi type air.[give or take
changes with the weather]

Casady

On Wed, 12 Sep 2007 00:44:05 GMT, Jere Lull wrote:

You say that viruses are smaller than sodium or chloride ions? I got
A's in college chemistry, and I have trouble believing it.

As I understand him from the past, the viruses are broken down to toxic
chemicals that will pass.

Thank you for relaying that little tidbit. I remain skeptical. I may
drop by the local waterworks and look at a few trade magazines. Check
out the ads for the millions of gallons a day RO plants.

Casady

Jere Lull wrote:
:On 2007-09-11 12:06:19 -0400, (Richard
:Casady) said:

: You say that viruses are smaller than sodium or chloride ions? I got
: A's in college chemistry, and I have trouble believing it.

:As I understand him from the past, the viruses are broken down to toxic
:chemicals that will pass.

Toxic chemicals smaller than a sodium or chlorine ion?

On Wed, 12 Sep 2007 15:28:03 +0000 (UTC), David Scheidt
wrote:

Jere Lull wrote:
:On 2007-09-11 12:06:19 -0400, (Richard
:Casady) said:

: You say that viruses are smaller than sodium or chloride ions? I got
: A's in college chemistry, and I have trouble believing it.

:As I understand him from the past, the viruses are broken down to toxic
:chemicals that will pass.

Toxic chemicals smaller than a sodium or chlorine ion?

I also liked the carbon molecules.

Casady

(Richard Casady) wrote in
:

I also liked the carbon molecules.

Casady



Ok, you got me. Carbon molecules are called.....

Lamp Black, which is what I'm filtering water through....
Graphite, a lubricant because different layers are loosely coupled
Diamond, whose existence is obvious.

Just for your reference:
http://www.edinformatics.com/math_science/carbon.htm
http://www.nyu.edu/pages/mathmol/mod...n/carbon1.html
http://chemistry.suite101.com/articl..._and_nanotubes
http://rich.en.alibaba.com/product/0...lar_Sieve.html

http://www.newscientist.com/article/mg12416962.700.html
I wonder if they made them?

http://en.wikipedia.org/wiki/Molecule
Molecule - at least 2 atoms joined by sharing pairs of electrons in a
covalent bond.

What school did you attend?


Larry
--
Search youtube for "Depleted Uranium"
The ultimate dirty bomb......

Richard Casady wrote:
On Tue, 11 Sep 2007 22:03:31 -0700, Keith Hughes
wrote:

Water vapor - what you can actually see -

Water vapor is a gas and is invisible.

You are correct, I should have said "mist". The point being that what
most people routinely think of as "steam" is not steam, but condensate.

Steam is the vapor phase of
water. Clouds are liquid water.

Yes, and clouds 'fly'. Hence the "water doesn't flow uphill" statement,
in this context doesn't...hold water.

The liquid is hundreds of times as
dense as the vapor, by the way.

Really?

Keith Hughes

Richard Casady wrote:
snip

The phase change from liquid to gas
takes place at a constant temperature, the boiling point,

Which isn't a constant temperature, as you address below..

and and the
last degree of heating below that point, is the same as any other
degree, one BTU per pound.

This is true from a physics perspective, but not, unfortunately from an
applications engineering perspective. Since the effectiveness of
whatever heat exchange mechanism you use is proportional to the delta-T
between the process and the exchange medium, each degree of process rise
requires more heat input into the system than the previous one. Not into
the 'process', but into the 'system'.

This, IMO, is the crux of the issue of trying to use engine heat for
evaporation (i.e. distillation), versus just preheating. For an
efficient process, the engine-to-transfer medium exchanger needs to run
with a significant delta-t, and so to does the transfer
medium-to-process exchanger. This two-step cascade would likely require
much higher engine operating temperatures than normal, with all the
attendant maintenance and longevity issues.

In round figures, seven eights of the
energy goes into the evaporation, one eighth to temperature change.

Boiling point varies greatly with pressure, but I assume that we are
all talking about ordinary sea level, 14.7 psi type air.[give or take
changes with the weather]

Casady

Keith Hughes

Richard Casady wrote:
On Wed, 12 Sep 2007 00:44:05 GMT, Jere Lull wrote:

You say that viruses are smaller than sodium or chloride ions? I got
A's in college chemistry, and I have trouble believing it.

Smaller isn't necessarily the issue with retention of ionic species. A
membrane that electrostatically adsorbs ions can still pass much larger
non-polar molecules and materials.

As I understand him from the past, the viruses are broken down to toxic
chemicals that will pass.

Thank you for relaying that little tidbit. I remain skeptical. I may
drop by the local waterworks and look at a few trade magazines. Check
out the ads for the millions of gallons a day RO plants.

Casady

There are a number of studies showing that RO membranes (which are not
absolute porosity filters, but are spiral wound depth filters) are not
100% viral retentive, or bacterial retentive (especially for Giardia
oocytes, and certainly not for mycoplasma) when challenged with a
significant upstream population. The prevalence of these organisms (and
almost-organisms) in seawater is, however, extremely low, and a 2 to
3-log reduction (about what the literature seems to support) gives a
very high probability of 100% removal. Safer than tap water, by a long shot.

As for viral proteins being toxic, the only studies I'm aware of have
been done on the common viral pesticides, where no oral toxicity has
ever been observed - doesn't mean it can't happen, but given how rapidly
protein is denature in the stomach, it's pretty unlikely. For
injectables, some hepatotoxicity has been shown in mice injected with
solubilized viral proteins - hence my reluctance to inject RO water
while out sailing...

The DNA/RNA does not appear to be orally toxic either.

Keith Hughes

On Wed, 12 Sep 2007 23:17:40 -0700, Keith Hughes
wrote:

This, IMO, is the crux of the issue of trying to use engine heat for
evaporation (i.e. distillation), versus just preheating. For an
efficient process, the engine-to-transfer medium exchanger needs to run
with a significant delta-t, and so to does the transfer
medium-to-process exchanger. This two-step cascade would likely require
much higher engine operating temperatures than normal, with all the
attendant maintenance and longevity issues.

There is no escaping the simple fact that equipment for using the
waste heat from an engine for distillation was around for decades. Off
the shelf. It was intended for boats, of all things. RO may have
killed them off, however. Why do you insist that proven, available off
the shelf [ at one time, at least,] equipment cannot work?
Under load, the exhaust headers on my car run yellow hot, with a
ninety MPH breeze cooling them Enough temperature difference?
Something like a quarter of the fuel goes to a hot exhaust. Three
quarters of the fuel burned in a gas engine goes to waste heat.
Diesels do a bit better, and get maybe one third as shaft work.

Casady