[Prev][Next][Index][Thread]

Re: MSDS

<snip>
>
>Re: Ozone, etc
>	I have been told in the past by someone who should
>know that the main product of the coil discharge is oxides
>of nitrogen, with ozone only a minor constituent of that
>"good coil smell".  Wonder if there is a plasma physicist
>in the group who can provide more info?
>	I wouldn't worry about the stuff from the electrodes,
>as there just isn't enough of it to matter.  (At least, with
>coils below the multi-kw range.)
>Ed
>
>
For the most part Ed you (or your source) is correct.  While I am not
designated a plasma physicist, I usually deal mainly with power and
propulsion physics.  In both I have dealt with MHD (MagnetoHydroDynamics)
specifically in plasmas (MHD Plasma Propulsion and MCF-Magnetically Confined
Fusion).  I do recall that in Fusion Reactor design especially, Ozone (O3 or
trioxygen) is an allotrope of oxygen and in reactor design it is constidered
a useful plasma form.  The ozone in a plasma contained within a magnetically
confined fusion reactor helps aid in reseeding the deuterium-tritium plasma
after Joule heating has deionized the plasma.  The ozone (called a inert or
neutral particle fuel) cases the deuterium-tritium plasma to reionize thus
allowing further Joule heating to take place (BTW Joule heating is not the
only way to heat the plasma to fusion temperatures but is usually the
easiest)...but this kinda off the topic!

As for the ozone being only a partial constituent of the smell so to speak.
One must remember that air is made up of:

Nitrogen (78.084 mole percent)
Oxygen (20.946 mole percent)
Argon (0.934 mole percent)
Carbon Dioxide (0.033 mole percent)
Neon (0.002 mole percent)
Helium (0.001 mole percent)


There are probably small fractions of other gases (pollution) in there as
well but that would depend on location.  

What is actually happening at the TC output terminal is as follows:  First
the high voltage causes the air around the terminal to break down the gases
[the O2(g) -> O(g) + O(g) and N2(g) -> N(g) + N(g)].  The other gases
breakdown as well but are negligible.  The single gas molecules then move to
the outer side of the corona and begin to bond with the other molecules in
the air that is outside of the HV effects (corona).  Thus if an O molecule
comes up to a O2 molecule it will usually bond to form a O3 molecule, ozone.
But you must remember that the nitrogen:oxgen ratio is about 4:1 so more
nitrogen molecules are present than oxygen molecules so the nitrogen oxides
you spoke of have a higher probability to form, thus decreaseing the chances
of ozone (O3) forming.  There are complex energy patterns and formulas to
show all this but I think you get the picture.  It is true to say that most
of the smell is nitrogen oxides, but you also have to realize that the smell
of nitrogen oxides and ozone are destinctly different, the ozone is usually
strong in oder and partially overpowers the nitrogen oxides.  It is rather
involved to create 100% ozone (even most that is in the upper atmosphere,
3mm thick at 1 atm and 0C, is not pure 100% ozone).


For those interested in the ozone layer itself...Ozone is the essential
component of the stratosphere (a region of the atmosphere beginning at about
15km above the surface of the earth).  The lower portion of the atmosphere,
near the surface of the earth, is called the troposphere.  If one moves
upward through the troposphere, one finds that the temperature usually
decrease.  But at 10km to 15km the temperature begin to rise.  This
temperature increase is caused by the absorption of UV radiation (between
200nm and 300nm) by ozone (O3), which is then broken down into O and O2 by
the UV radiation.  Ozone is formed by the reaction in the stratosphere by
the reaction:  O2(g) + O(g) -> O3(g).  Oxygen forms in the stratosphere when
O2 absorbs short wavelength UV radiation (<200nm).  The most energetic UV
radiation is filtered (absorbed) by the O2 in the upper atmosphere and the
remainder UV radiation is filtered (absorbed) by the O3 (ozone) in the
stratosphere.

ChloroFluoroCarbons (CFC's) [especially, but not soley, CClF2 and CCl2F2]
are a source of chlorine atoms that act to catalyze the decompostion of
ozone, thus it is destroyed faster than it can be produced.  CFC's being
inert, rise into the atmosphere, when they reach the UV radiation they
breakdown and Cl atoms  are formed, these Cl atoms act as theives and steal
an oxygen (O) atom from the ozone.  The ClO molecules then act as a chlorine
chain:

Cl(g) + O3(g) -> ClO(g) + O2(g)
ClO(g) + O(g) -> Cl(g) + O2(g)
-------------------------------
O3(g) + O(g) -> 2O2(g)

The net result is the decompostion of ozone to dioxygen.  The chlorine atoms
are consumed in the first step of the reation, but are regenerated in the
second step, thus they act as a catalyst.

There is a GREAT possibility that I'm wrong on some of the above, if so
someone please correct me...

Well enough babbling for now...

Tim
+------------------------------------++---------------------------------+
] Timothy A. Chandler                []   M.S.Physics/B.S.Chmeistry     [
+------------------------------------++---------------------------------+
| NASA-Langley Research Center       --   George Mason University       |
| Department of Energy               ||   Department of Physics         |
| Fusion Research Team- Alpha        ||   Department of Chemistry       |
| CHOCT Fusion Reactor Designation   --   OPC-EFC                       |
+------------------------------------++---------------------------------+
)                 Private Email Address:  tchand-at-slip-dot-net               (
+-----------------------------------------------------------------------+