Gasification Archive for August 2002

Dosing 

Dosing is done by a dosig screew and a weighband before the feeder.
The rotation speed of the dosing screw is controlled by a frequency converter.

Plug breaker

The plug breaker has the purpose of down sizing the plug after the sealing. In order to avoid blockage under the plug breaker the cutting head is mounted with a screw section below the head. 

Feed screw

The feed screw is feeding the biomass into the reactor. 

The Fuel control system.

The fuel control system consist of a mass measurement and a moisture measurement placed as close to the gasification process as possible. 
This means that there is a dead time of 15-20 second from when the fuel mass and moisture is measured until it is entering the reactor.
By measuring the mass and the moisture, the heating value of the fuel can be estimated with good accuracy assuming that the ash content is constant and low. 

Fuel quality.

This system will work with biomass with a particle size from 0 to 100 mm. The system can work with input bulk densities in the biomass from 50 to 350 kg/m3. 

Fuel feeding accuracy.

Each fuel line will feed one piston stroke every 3 seconds. 
The fuel feeding accuracy at mass base at a capacity of 6000 kg pr hour will be: 
The mass variations measured over 1 second will be from - 90 % to + 160 % of nominal capacity.
The mass variations measured over 3 second will be from - 15 % to + 15 % of nominal capacity.
The mass variations measured over 60 second will be from - 5 % to + 5 % of nominal capacity.

Inert gas consumption

Maximal inert gas consumption is 20 Nm3 gas pr. hour.


If any one are interested in more details you are velcome to contact me at 
Phone +4546191554 or mail tk@tke.dk

Best regards

Thomas Koch

----- Original Message ----- 
From: "Tom Miles" <tmiles@trmiles.com>
To: "gasification" <gasification@crest.org>
Sent: Tuesday, August 20, 2002 1:26 AM
Subject: GAS-L: Biomass Gasification and Feeding


> Subject:     Biomass Gasification and Feeding
> > 
> > 
> > 
> > 
> > I've been following with interest the recent exchanges between Tom Reed,
> > Tom Miles, Thomas Koch and others over biomass feeding, in particular the
> > feeding of bagasse.   This topic has also surfaced several times in the
> > past.   SRI's James Joyce has recently posted a brief commentary on our
> > development work.   My purpose with this brief commentary is to bring the
> > gasification community up to speed with where the QBIG gasification
> > development and SRI's feeder development is at right now.
> > 
> > I'm encouraged by Tom Reed's comment on 4 August ".... the world's most
> > difficult feeding fuel - raw bagasse from sugar cane".  Chopped straw is
> > not too far behind !!!   Our considerable experience with the handling of
> > raw bagasse at high rates in Australian sugar mills has told us that over
> > many years.  But to the point.  Put simply, SRI and University of
> > Queensland, Chemical Engineering (as part of the QBIG gasification
> > syndicate) embarked on the development of bagasse gasification technology
> > integrated with a sugar mill (that combination provides unique hot fuel gas
> > process advantages not found anywhere else) because of a host of technical
> > and economic reasons.   Whether those reasons remain strong into the future
> > remains to be seen !!!!  But for now these still exist.
> > 
> > But in setting out on this journey, based on our own extensive experience
> > and judgement and with the benefit of the work done elsewhere around the
> > world on biomass gasification, we settled on two basic principles to
> > underpin our gasifier development (1) the process has to be pressurised
> > (although this has yet to be confirmed with detailed engineering, process
> > design and costing for Australian circumstances) and (2) we needed a whole
> > new feeder for bagasse and cane trash.   Based on the Maui experiences
> > directly, on our own long experiences with the screwing of bagasse and the
> > commercial operating experiences of a sugar mill feeding bagasse using lock
> > hoppers for furfural production, any screw device was not acceptable, and
> > other devices including lock hoppers did not fit the goals.  But as Tom has
> > said, bagasse being bagasse, you need a damned good feeder to feed bagasse
> > whether the pressure is 25 bar or 2 bar (so called atmospheric - although
> > rotary valves would be okay here).   Remember that our primary goal in all
> > of our development work has been to focus on technology that would deliver
> > commercially sustainable plant.  The feeder that we have now developed,
> > even though it is quite small, has all of the engineering and process
> > features that can be readily scaled-up to the rates that we need for our
> > proposed BIG/CC projects in our large Australian sugar mills.  Raw bagasse
> > feeding rates of between 20 and 70 t/h per feeder will be required.
> > Notwithstanding Thomas Koch's admirable developments with his piston
> > feeder, the intermittent piston approach was judged not to be acceptable
> > for our goals - we needed continuous feeding at high very rates.
> > 
> > We have now successfully developed a continuous bagasse feeder that has
> > been tested at rates up to about 5 t/h (not sure of the exact figure) for
> > test periods of up to two minutes. That is as long a test time as out
> > developmental rig will allow us.  Our experimental data tells us that this
> > has been more than sufficient time to establish stable and consistent
> > operating conditions  in the feeder.  The feeder operations over that time
> > also tell us that the real world engineering issues that have to be
> > addressed are being addressed, and the feeder can be scaled-up to much
> > larger sizes.  The current feeder size was selected to be a direct
> > application for our proposed 15 MWt (~ 5 MWe) demonstration gasifier, now
> > in the planning stages.  The particular technology for our feeder comes out
> > of our extensive experience with the milling of bagasse to extract sugar
> > juice.
> > 
> > I would be happy to provide more information and comment on bagasse feeding
> > and gasification in general to those interested as you make contact with me
> > directly or through the gasification network.
> > 
> > Dr Terry Dixon
> > Manager Engineering Group
> > Sugar Research Institute
> > Box 5611
> > Mackay MC 4741
> > AUSTRALIA
> > Ph:  +61 7 49527600
> > Fx:   +61 7 49527699
> > Mb:  0418 185 309
> > email: t.dixon@sri.org.au
> > 
> > 
> > -------------------------------
> > 
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> > and privileged information.  Any unauthorised alteration, disclosure or
> > distribution is prohibited.  If you received this email in error, please
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> > 
> > Any confidentiality or legal professional privilege is not waived or lost
> > by any mistaken delivery of the email.
> > 
> > -------------------------------
> 
> 
> 
> 
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Gasification List Archives:
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Gasification List Moderator:
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www.webpan.com/BEF
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Other Gasification Events and Information:
http://www.bioenergy2002.org
http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon