Hi, Kevin.
So many questions, so little time. I shall attempt to give you some answers,
but they are subjective to linear hearth architecture. My responses will
follow your text and be preceded by "==>".
###
1: For a given gasifier design, feed size is extremely important
==> I believe feedstock size is no more important than feedstock
preparation. There is no magic involved in the process, but there are basic
laws that must be observed if one is to make a good gas. Let's face it,
applied science still rules the roost.
###
2: For an otherwise good gasifier design and feedstock selection, the
presence of leakage is extremely important. (Presumably, this means
air leakage IN, in a suction system, and gas leakage OUT in a
pressurized system.
==> I was taught that a cornerstone of making good gas is intake air
management. It controls the temperature which enables proper conversion. If
one does not have an airtight system, one cannot possibly manage air flow.
###
3: Testing of the design and fuel selection, and final "tuning" is
extremely important.
###
: FUEL SIZE
The "Engine Grade Gas"(EGG) successes we see on this list seem to fall
into two categories:
A: Those who use chunkwood fuel (such as Wayne Keith, Mike Larosa,
Powerhearth, Vesa Mikkonen)
B: Those who have instrumented systems and do extensive testing and
utilize "on line controls."
C: Chip fueled gasifier systems, such as Greg Manning's system. Greg
has reported extensively on the use of screened wood chips being used
in his "Heating Grade Gas" (HGG) system, but I am not sure if his
system has produced EGG on a continuous basis. (Perhaps Greg could
clarify whether or not his system will produce EGG on a consistent
basis.)
==> The Powerhearth is easily able to gasify chunks, chips and briquettes
with equal success and without adjustments other than calibration and
setting the data points into the program/PLC.
Personally, I like chunks for their char quality.
###
While chunkfuel is the preferred fuel size, what would you suggest as
the minimum size of fuel that teh "Home Gasifier Builder" should
consider, to avoid major problems, and to have some reasonable
expectation of success?
==> Kevin, it would be unfair of me to pretend to know the proper answer. I
have never built a gasifier outside of a sheetmetal shop, with our own
drawings and using uniform materials. I have, however, seen many units made
privately, all of round hearth architecture. My response to similar
questions has always been the same. I don't know, but don't be afraid to
experiment. Make friends with your gasifier and learn what she likes. Never
put the cart before the horse.
###
More specifically, what do you feel is the likelihood, and the
circumstances under which a Woodgas List Member could build an EGG
gasifier that ran reasonably well using screened wood chips that were
available free from a Tree Surgeon, or right-of-way clearing Contractor?
==> I have no experience in that area. We buy many tons of chips from local
sawmills and with our system, moisture content is a non issue.
###
2: AIR LEAKAGE
Would you have any suggestions on the best way to test for leaks, and
to diagnose the probable area of leakage? Would you have any
suggestions on the amount of air leakage that would be acceptable?
==> Proper welds and proper gaskets, plenty of pipe dope at threaded joints.
Build airtight and, if done properly, it stays airtight. No amount of
leakage is acceptable if you are serious about good gas!
###
3: TESTING and TUNING
Would you have any guidelines or suggestions for testing and
evaluating a home built gasifier, such as:
3:1 What is a good way to measure tar content of gas?
3:2 With the test you suggest, is there any way quantify it, so that
teh Builder would know if the tar content is low enough to allow a
typical engine to run for a minimum of say 1,000 hours?
3:3 What would you recommend as the minimum requirement for test
equipment for the home builder?
3:4 What tests would you suggest?
3:5 When designing and building a gasifier, what are the minimum
provisions that the Back Yard Builder should make for testing and
tuning? (eg, Viewports, temperature and pressure measuring points, etc)
==> Kevin, I don't know. I would think a backyard builder would have a plan,
an agenda and a budget.
We shall be assembling and testing a model before shipping and
commissioning. The process lasts about a week and a half and is pretty
intense. If there is any interest in dropping in for the sake of observing
and/or learning, contact me off list. We would be pleased to welcome you to
a Vermont summer of long hours, but good coffee and tea.
###
Kevin, I'm sorry I couldn't be more helpful, but it seems an exercise in
futility to pontificate about that which one has a high degree of ignorance.
Respectfully,
Bill Klein
3i
Your helpful comments will be very much appreciated, and will go a
long way to preventing Home Gasifier Builders from wasting time on
gasifier and fuel combinations that are very likely to fail.
Thanks!
Kevin
Quoting Bill Klein <[email protected]>:
Hi, Kevin.
Your question of feedstock size is rather interesting and one to which I
can
easily relate. That said, I hope the following provides a little bit of
insight and doesn't aggravate the experts on this list.
Before we ship our units, they undergo several tests.
Test 1 is a 24 hour non stop test in which we push all of the limits. Said
differently, we look for the weaknesses, leaks, etc.
Test 2 is another 24 hour non stop test. It provides us with systems
calibration.
Test 3 is a 100 hour non stop test. During this period, all of the
necessary
data points are established for our automation and management system.
Why am I describing an important phase of our unit fabrication, truncated
as
the description may be?
I wanted to point out the importance of properly sized feedstock for, if
there is a screw up with gas flow or aglomeration, the test is stopped and
rerun.
When we test, depending upon the customer's intended feedstock, we test
and
evaluate the gas from at least three feedstocks, one of which is a close
approximation of that which the customer will use. Size of the feedstock
is
critical unless one really enjoys non stop runs, grumpy technicians and
buckets of coffee.
Pellets: We won't use them. They are seldom uniform (cross sectionally) in
moisture content and generally sealed. With heat, they shatter
magnificently, leaving a pile of sawdust. The exception seems to be
pelletized switchgrass: a great feedstock.
The chip size we like resembles an Oreo cookie, squared. As an
approximation
it works to gauge sizes. Overall length or width uniformity doesn't seem
to
be as critical as thickness. Still, there is a lot of flexibility and
smaller sizes are okay to integrate, as an exception, not the rule.
Gasifiers are not stoics. Built properly, they have some versatility, but
you have to make friends with your unit before you learn her secrets. Then
you merely have to respect them. .
Charcoal briquettes as a feedstock too often creates a huge problem as
they
plug the grate with compacted fines.
The best and my most favorite feedstock is still chunks. 2x4x4 - or
briquettes of almost anything.
Kevin, I would have gladly answered earlier, but you posted hours after my
bedtime. We old folks need our beauty sleep.
Respectfully,
Bill Klein
3i
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Tuesday, June 21, 2011 10:13 PM
Subject: Re: [Gasification] Any experience with Stak Properties 10K
gasifier?
Dear Bill
Quoting Bill Klein <[email protected]>:
To underscore Greg's email, repeating what I was taught, "The
quality of the gas is in direct proportion to the quality of the
char." Larger feedstock makes great char!
# OK!! Do you think one can make "Engine Grade Gas" using:
1: Wood pellets, 1/4" diameter, 1/4" to 1/2" long?
2: Wood chips screened to -1/4", +1/8"?
3: Wood chips screened to -1/2",+ 1/4"?
4: Wood chips screened to -1", + 1/2"?
Thanks!
Kevin
Respectfully,
Bill Klein
3i
http://www.3iAlternativePower.com
-- Original Message -----
From: Greg Manning
To: Discussion of biomass pyrolysis and gasification
Sent: Tuesday, June 21, 2011 7:40 PM
Subject: Re: [Gasification] Any experience with Stak Properties
10K gasifier?
Pete, (and list)
What, and how big, are the fuel chunks ?
most gasifiers do NOT like wood chips, or really "fine" fuel, the
interstitial space the gasifier is designed to run with, is
generally much larger than that of chips or fine feedstock, using
the correct sized fuel, in-turn, lowers the reaction core
temperature, thus creating more, and more consistant amounts, of CO.
(the main flamable gas, in woodgas). (H2 and CH4 are simply "bonus"
gases.....)
Greg Manning.
On Mon, Jun 20, 2011 at 6:01 PM, Pete & Sheri
<[email protected]> wrote:
Has anyone here had any experience running an engine using the
Stak Properties 10K gasifier?
They tell me that the JXQ-10 gasifier is a forerunner to this
machine. I have one of those. I?d like to be able to correspond
with others who have this style of machine. Currently I am having
mixed results getting a steady flow of good gas to run my 6.5 KW
Onan 1800 rpm genset from it. On Saturday, I got it to deliver
about 3.8 kw for about 12 minutes, but then the quality of the gas
deteriorated. On Sunday a similar test produced worse results, but
over about a one hour period, with gas quality again deteriorating
as the test went proceded.
I am not writing to waste the time of senior members here by
asking them to troubleshoot my problems, without enough info. Just
want to show what kind of issues I have for those who might be
involved with similar equipment.
My goals are to: 1. See how much power I can squeeze out of
the generator for an extended period of time with this gas source,
and 2. To get some actual experience making woodgas.
Looking back over my videos and notes, I can see a dozen or two
things that I could do better next time.
Pete Stanaitis
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--
Regards,
Greg Manning,
Brandon, Manitoba, Canada
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