Updraft counter-current systems suffer from intrinsic high tar production and
if one burns the tarry gas near the reactor, it may appear to be high in
heating value, but really isn't without the tars. There are other factors which
may affect the gas heating value after distances and I have seen this when the
percent of tar is high.
There are other than downdraft designs that will produce low tar
content gas that saves a lot of downstream handling of tars which is never
really productive to economics or overall success of gasification. The design
doesn't require a briquette feed, can handle MSW, tires, dried sewage sludge
and other waste materials.
It is surprising that with the number and preponderance of downdraft,
briquette fed gasifiers that you didn't use one, but there are issues with
using larger ones of this configuration.
Removing the contaminants from the water can be an issue also, but if
you know some basic chemical properties of the mixed tar oil water stream, it
can be cleaned up rather easily. Even the low tar content downdraft gasifiers
produce contaminants in the gas stream that should be removed prior to engine
operation to prevent engine damage, lowered heating value into the combustion
chamber. For thermal operations such as an oven, with long distance piping and
acid water in the gas, comes corrosion, potential freezing, water accumulation
and potential dumping or dripping into the gas combustion area, or blockage of
flow in the piping system.
An interesting experience with a high profile gasification and other
chemical process modeling group was during a demonstration when they went into
great detail about an IGCC coal project their complex spreadsheet did not take
into account tar production and removal from the reactor output gas stream.
When I asked the demonstrating engineer about it, he initially said "Tar
production would depend on how much is put into the reactor" then I explained
that tars were spontaneously produced in a gasifier and he said that they would
look into it. So, if one wants to build a successful gasification system, don't
use the modeling programs for your design.
Thermogenics is seeking a third party reviewer of out technology for
financing sources. The qualifications have to include experience with
successful design, construction and operation of a gasification system, and
this cannot be a two stage combustor which many tout as a gasifier but isn't.
Although there have been project failures such as Range Fuels, my understanding
is that the gasifier worked but the catalyst didn't, so someone who worked on
the gasifier system may still be eligible.
Thermogenics finds it amusing to watch the industry do the same things
over and over again and have repeated brain damage around the world from doing
so. We have parties who realize the value of the decades of work to address the
problems and are wisely working in licensing the technologies to accelerate the
field. The technologies are feeding, ash discharge, gas cooling without using
fixed, foulable surfaces or liquid sprays, water treatment, residue
neutralization, process control architecture using 2 wires for control and 2
wires for power distribution, overall single layer platform for process control
without PLCs, and other process simplifications.
The other global aspect of gasification is that it is one of the fields
still able to show good economics in the sinking energy price field, when waste
is used, but the financing world is well aware of the muddy tracks left in the
field that it is gun shy of getting into it. Any more plasma or pyrolysis
technologies get funded and go bust, we all suffer and the field gets farther
and farther away from acceptable in the financial world.
Sincerely,
Leland T. "Tom" Taylor
Thermogenics Inc.
www.thermogenicx.com
-----Original Message-----
From: Mano Va <[email protected]>
To: Discussion of biomass pyrolysis and gasification
<[email protected]>
Sent: Thu, Feb 25, 2016 9:20 pm
Subject: Re: [Gasification] Producer Gas issues in a baking oven
Hi srini sir,
1.Tar content based on your gas outlet position and I want to know your gas
outlet temperature
2.Above 450 'C its possible to reduce tar but in updraft Pyrolysis gas also
mixed in it
3.Duel fuel Oil burners may help to solve this issues
Regards,
Manova.M
On Thu, Feb 25, 2016 at 8:13 PM, Srinivas Nuti <[email protected]>
wrote:
Dear all,
We have installed an updraft gasifier of 8 TPD capacity using biomass
briquettes for substitution of LPG in a baking oven of temperature of 170 C.
The gasifier is air based atmospheric updraft. The producer gas generated has
successfully erected and commissioned.
But we have observed these issues in one out of 3 ovens while the other two are
working fine.
We have faced these problems with burner of third oven.
1) It ran for 6 days but later on the producer gas is not able to catch fire at
the burner end.
2) Due to lack of flame burner does not start.
3) We have installed tar condenser anticipating tar choke on burner nozzle, but
still no positive results.
Your guidance and experience on the same is highly appreciated.
with best regards,
Srinivas Nuti
ᐧ
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