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<DIV><FONT face=Arial size=2><STRONG>Hi Peter and
Colleagues,</STRONG></FONT></DIV>
<DIV><STRONG><FONT face=Arial size=2></FONT></STRONG> </DIV>
<DIV><STRONG><FONT face=Arial size=2>Appreciate this level of information, and
know the work it takes to record all these details:</FONT></STRONG></DIV>
<DIV><FONT face=Arial size=2> <BR>> In this message I will only focus on
the gas out of the RPS linear <BR>> hearth, it is already long winded but am
attempting to provide as much <BR>> detail as possible without compromising
proprietary bits.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2><STRONG>For the reason of retaining your propriety
bits, my comments have to be restricted, so that what you have and how you think
it works, is retained. </STRONG></FONT></DIV>
<DIV><FONT face=Arial size=2> <BR>> Doug has mentioned our gas analysis
as being "very unusual" for an air <BR>> drawn system so for the benefit of
the list I provide it here so people <BR>> can see for themselves:<BR>>
<BR>> Major Gasses,<BR>> Hydrogen: approx 36.00%<BR>> Carbon
Monoxide : approx 28.00%<BR>> Nitrogen:
29.00%<BR>> Carbon Dioxide: 6.81%<BR>> Low
level Gasses,<BR>> Oxygen:
Less than 0.02%<BR>> Methane: 0.96%<BR>>
Argon: 0.37%<BR>> There were also a range of minor
gases in the less than 50ppm range.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2><STRONG>The high H2 is unusual in a downdraft
gasifier, but it's creation results from how the char bed behaves in
"certain" conditions of design. This design also sees the CO and other
combustible gases, form in a way that while "different", can be
explained, and is confirmed by the waste char, and flare
colours.</STRONG></FONT></DIV>
<DIV><FONT face=Arial size=2> <BR>> The flow rate measured at the time
of the test was 130m3/hr, though <BR>> this was not recorded on the lab
certificate.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2><STRONG>We learn as we go, but testing times should
begin after the system has reached it's heat operating soaked temperature, and
then measured over a range of flows. Depending on the intention of the tests,
not just gas analysis, the test time should be extensive enough to show that the
gas making is sustainable with the selected fuel.</STRONG></DIV>
<DIV> <BR>> This is not full flow and the same system has been measured
up to <BR>> 400m3/hr without apparent over aspiration for a 20 minute run
before <BR>> overheating of the fan motor caused it to trip. The
sustained upper <BR>> limit has not been determined and may well be lower or
higher (it has <BR>> taken a while to get a suitable high temperature fan of
adequate <BR>> capacity, but will have one within the next few weeks, like
most <BR>> components we have ended up building this ourselves), but the
system is <BR>> quite comfortable at 200m3/hr with similar gas quality
observed in the <BR>> flare and can be turned back to 40m3/hr without losing
this</DIV>
<DIV> </DIV>
<DIV><STRONG>Hot gas suction fans can be a high maintenance component. The gas
outputs can be estimated given sufficient information, but, in this case, you
have proprietary knowledge protection and I will not breach that in order to
explain for the benefit of others.</STRONG></DIV>
<DIV><STRONG> <BR>></STRONG> <STRONG>snip<</STRONG><BR> <BR>>
We have made numerous attempts to engage university researchers to <BR>>
formally measure system performance without any real success.</DIV>
<DIV> </DIV>
<DIV><STRONG>Not easy to do any where, unless you find one set up to do gas
analysis, then make a department donation for a test to be done. Better know as
bribe with cash.</STRONG></DIV>
<DIV> </DIV>
<DIV><STRONG>>snip<</STRONG></DIV>
<DIV> <BR>> Condensate test results RPS first development unit<BR>>
<BR>> Percentage Compound<BR>> 40.625
Pyridine C5H5N<BR>> 2.298 Column
Bleed<BR>> 7.509 Phenol C6H6O1<BR>>
0.750 Methyl Phenol C7H5O1<BR>>
1.305 Methyl Phenol C7H5O1<BR>> <BR>>
3.340 Naphthalene C10H3<BR>>
0.529 Dodlecene C12H24<BR>>
1.163 1 Methyl Naphthalene C11H10<BR>>
1.097 2 Methyl Naphthelene C11H18<BR>>
0.566 Tetradecine C14H28<BR>>
5.092 Biphenylene C12H8<BR>>
0.562 2, 3 Dimethyl 1 Naphthelene
C12H12<BR>> 0.869 Dibenzofuran
C12H8O1<BR>> 0.674 ?<BR>> 1.125
Fluorene C13H10<BR>> 0.818 ?<BR>>
0.552 ?<BR>> 9.291
Anthracene C14H10<BR>> 2.077
Anthracene C14H10<BR>> 0.777
Anthracene C14H10<BR>> 1.626
4HCyclopentaphenathracene C15H10<BR>>
0.806 1methylAnthracene C15H12<BR>>
0.951 2Pheny1Naphthalene C16H12<BR>>
6.725 Fluroanthene C16H10<BR>>
1.762 Pyrene C16H10<BR>>
7.112 Fluroanthene C16H10<BR>>
100.001</DIV>
<DIV> </DIV>
<DIV><STRONG>This incorrectly done condensate analysis taken from the gas bag
walls, are a few of over 200 chemical compounds found in the unstable chemistry
of pyrolysis gas in the fuel hopper. When found in the final gas supply
after the gas cleaning,etc, indicate that the tar cracking is less than opimised
for either the output, or the type of fuel being tested.</STRONG></DIV>
<DIV> <BR>> Doug also indicated that if we are only getting low
overall condensate <BR>> levels then the water is probably going out with the
gas as steam, and <BR>> ordinarily I would agree, except none of our
observations of our linear <BR>> system whilst operating on optimal fuels
support this.</DIV>
<DIV> </DIV>
<DIV><STRONG>The key word here is optimal fuels which create the right gas
making for all gasifiers. It is however agreed already, that more moisture can
be turned to H2 "if" in beds are performing a certain
way.</STRONG><BR> <BR>> The condensate analysis above does not show any
free water at all (we <BR>> did query this at the time and asked whether this
result was after water <BR>> had been excluded, ie reporting only the
percentages of the non water <BR>> component, but were told no, if water had
been present it would have <BR>> been reported).</DIV>
<DIV> </DIV>
<DIV><STRONG>The material collected from the bag wall would have the appearance
of light oil, or thin grease. They float on water, but do not take it up, and
if left out in the open, they literally evaporate.</STRONG></DIV>
<DIV><BR>> Before I go on I would add that yes we have seen wet gas out of
the <BR>> system, but only when running truly excessively high mc feed stocks
in <BR>> the range of 30-50%. At 40% mc H2 drops to as little as 5% and CO to
11% <BR>> with a corresponding increase in CO2 & N2 (lab analysis result
during <BR>> testing of mixed wood chip/ sewerage sludge blends). Stretching
a length <BR>> of paper towel over the (un-ignited!) gas stream under these
conditions <BR>> results in it getting rather damp quite quickly, and a brown
condensate <BR>> dripping off the outer rim of the flare head can be observed
(no funny <BR>> comments about the possible relationship to sewerage sludge
please...). <BR>> Under other much less extreme gasification conditions
though no moisture <BR>> collecting in the paper or free liquids on nearby
metal surfaces are <BR>> readily apparent.</DIV>
<DIV> </DIV>
<DIV><STRONG>Environmental conditions are also a factor affecting condensate
formation, as is altitude. The dew points of producer gas drop accordingly with
dryer fuel. The fact that sewage sludge is a hazardous waste for biological
reasons, would seem to be ignoring the problems of heavy metal emissions,
specifically mercury. Testing with an incorrectly operating gasifier,
is no test at all, unless it is operating in a very thorough tar cracking mode.
This first ensures that the pyrolysis gases are fully disassociated, and then
the mercury is taken up by the activated carbon that fills the reduction
zone. If you do this again, then ensure you are doing emission testing as
well as the gas analysis.</STRONG><BR> <BR>> The following additional
observations are for "chunky" wood fuels below <BR>> 25% mc (the fuel spec at
the time of the formal gas analysis, piece <BR>> sizes ranging from 25mm to
50mm on a side).</DIV>
<DIV> </DIV>
<DIV><STRONG>Width and thickness also affect char formation
behaviour.</STRONG></DIV>
<DIV> </DIV>
<DIV>> * Yes we do have gas cooling (of our own design like the rest of it),
<BR>> and gas exit temperature immediately prior to the flare head are
between <BR>> 40oC and 70oC, depending on flow rate, and the current system
also <BR>> includes mesh mist filters on the exit from the coolers, which we
<BR>> thought might also be an efficient way of trapping the sub 10 micron
<BR>> particulates, assuming that these would be wetted by condensate. </DIV>
<DIV> </DIV>
<DIV><STRONG>This is probably why you do not see much condensate. I have
seen dew points of producer gas go down to around 30C, but not made any real
study of all the permutations possible. One thing for sure though, is that if
you have submicron carbon blacks in your output gas, then they are there because
of moisture still in the gas. Dry gas cannot carry particulates in
suspension.</STRONG></DIV>
<DIV><STRONG>>snip</STRONG></DIV><STRONG></STRONG>
<DIV><BR> > * The system "chuffs" when the mc is below 25%, a resonance
coming from <BR>> the intakes sounding a little like a fast revving steam
engine and the <BR>> upper hopper vibrating like a long, low drum roll....
Hand held digital <BR>> anemometer also records this as a regular, fast
pulsing of the air <BR>> intake flows.</DIV>
<DIV> </DIV>
<DIV><STRONG>You are seeing a phenomena created in the oxidation
char, where the interstitial space opens up channels or caverns usually
beginning in front of the air inlets.The normal process of oxygen connecting
with carbon in a continuous ribbon to where the gas exits the char is
disrupted. On entering the hole in the bed, the CO on the surface of the char
flashed creating a mini explosive pulse. This combustion flash results in
CO2, and that quenches the flare, but makes more CO ready for the next air flow,
by reduction, reducing the temperature </STRONG></DIV>
<DIV><BR> > This seems consistent with a rapid cycling of water cracking
and the <BR>> free oxygen made available displacing that from the incoming
air. This <BR>> cracking uses up thermal energy which then drops below
the threshold <BR>> required to support this water shift reaction, and the
process pauses, <BR>> reverting to pulling in outside air to satisfy the
oxygen demand, </DIV>
<DIV> </DIV>
<DIV><STRONG>I cannot separate this possibility from my previous comment,
but the bed channelling and holes in the bed do provide more dwell time for the
formation of H2, because the gas velocity is lower than in a packed carbon
bed.</STRONG></DIV>
<DIV><STRONG>>snip<</STRONG></DIV><STRONG>
<DIV><BR></STRONG> </DIV>
<DIV>> *Charcoal from the ash bin has a very high fixed carbon in the 85-93%
<BR>> range (reported by a NATA certified lab) consistent with high <BR>>
temperature. </DIV>
<DIV> </DIV>
<DIV><STRONG>High fixed carbon char is great for burning and carbon sinks,
and it will have other uses as well. It is not however activated carbon, which
is light and fluffy, and is the result of the gas being made by reduction, an
important requirement if you are going to play with contaminated fuels. The char
you show and have tested, may be made by high temperature, but when
found in a gasification system, originates in the slow moving char that has no
gas flows through it. <FONT color=#ff0000>(no further
comment)</FONT></STRONG></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Soot taken from the particulate collection system below the <BR>>
cyclones has been examined with a microscope and we are told it had a <BR>>
crystalline structure normally also only found when forming under high <BR>>
(>1000oC) temperatures.</DIV>
<DIV> </DIV>
<DIV><STRONG>Crystalline soot's are reformed from the pyrolysis gases, not the
char.( <FONT color=#ff0000>I don't wish to comment further on this, as it
affects what Peter might call proprietary knowledge.)</FONT></STRONG></DIV>
<DIV> <BR>> My wife Kerry, equal co developer, has asked that I also
point out when <BR>> we designed the original system we made allowance for
running it in <BR>> either downdraft, or updraft, mode and have used this
facility to break <BR>> up bridging on occasion when working with difficult
fuels (though on the <BR>> early units this does interrupt the gas flow to
the flare). The current <BR>> (Mark 3.2?) under construction allows for this
without stalling the <BR>> system. This was done as part of improving the
overall material handling <BR>> side on the path to a more easily automated
commercial model.</DIV>
<DIV> </DIV>
<DIV><STRONG>Whenever you see bridging of the fuel, you can create bed
conditions and gas analysis similar to the RPS gasifier, which Peter has honed
to his liking. Round gasifiers behave exactly the same where they have deep
beds, and how they work will depend on how good your suction fan performs. I
assume that the current system Peter, has no fuel feeding, or waste clean out,
and is all manual? If so, then automation may very well completely change
the way the it all behaves.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>In closing, it is necessary to appreciate that gas can be made from
any combustible materials, and multi testing of fuels has been done many times
over. It cannot prove that a gasifier is different from others, just by making
gas, that's the easy part. Remember that if the gas making is not working
correctly, then you have to start adding components to make it do
so. It's a good reality check to review how much effort it takes to keep
the gas flowing. </STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>My spare time is up folks, and I have to drop out of sight again,
but will watch ongoing discussion.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
<DIV><STRONG>Doug Williams,</STRONG></DIV>
<DIV><STRONG>Fluidyne Gasification.</STRONG></DIV>
<DIV><STRONG></STRONG> </DIV>
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