On 05/01/2016 1:28 PM, Peter Davies wrote:
Dear Tom,
The end of 2015 has been very busy for us, and
the start of 2016 looks even busier. Essentially
we have successfully proven our gasifier systems
with high ash, pelleted ag-residues in a high
temperature, low tar gasifier scenario with
simple dry scrubbing. Even when slightly over
aspirated with some residual oxygen coming
through the tars were limited to low viscosity
condensates (and very little of these), though
the gas quality varied slightly with the
appearance of some C2-C8 hydrocarbons (nothing
higher though, within detectable limits of the
GC system used by the lab). We also now have one
of the leading European CHP providers sign off
on our gas quality for use in their IC engine
systems, so expect to be able to supply complete
turnkey plants shortly which have a global
support network.
Yes it does require a pelleting step at this
stage, but we are working with a couple of
pellet equipment manufacturers for a lower cost,
gasifier optimised pellet which will be
substantially cheaper and lower maintenance than
conventional wood pellet plants used for the
combustion industry. Accompanying innovative
financing for village scale densification
systems is also now well advanced.
So we don't agree that water scrubbing is either
necessary or where gasifiers will be in the
future. However if you only have old gasifier
tech to work with then you can try torrefied
sawdust filters to recirculate your scrubber
water through, our early testing found these
very effective till we fixed the hearth core in
the gasifier design so they were not needed.
New Years Cheers,
Peter
ID Gasifiers Pty Ltd
Australia.
On 5/01/2016 2:31 AM, Tom Miles wrote:
Since 2005 hundreds of small scale gasifiers
have been installed in Myanmar, Cambodia and
other South East Asian countries to offset high
cost diesel to generate shaft and electric
power in rice mills and palm factories. They
are often in the 100+kW scale. Initially they
were dual fueled with diesel but increasingly
they are 100% producer gas. Ankur Scientific
introduced a dry cleaning system in 2009 but in
most cases the gasifiers use water scrubbers
and the waste water and sludge is discharged
into ponds without remediation. Simon Shackley
and others have published a thorough
characterization of waster waters from several
gasifiers.
Crop residues are best gasified at low
temperatures. Low temperatures generate tars.
Scrubbers are the lowest cost cleaning
technique. Water strips toxic chemicals from
the gas which become carried into the
environment with water and sludge. Gasifier
char is very useful. Sludge and black water are
dangerous.
The remediation of gasifier wastewater is a
challenge for us. As we look forward to
installing small scale gasifiers around the
world we need to solve this problem . What are
your solutions for filtering and remediating
gasifier scrubber water? One solution might be
running continuous blowdown though a vegetated
biological filter where the biochar is used as
part of the media. What have you tried?
Tom
T R Miles Technical Consultants Inc
Portland, OR 97225
[email protected] <mailto:[email protected]>
www.trmiles.com <http://www.trmiles.com>
Tom, what about VCD using waste heat from the
gasifier ? Possible ? David Murphy
Characterisation of waste water from biomass
gasification equipment: A case-study from Cambodia
Article in World Review of Science Technology
and Sustainable Development
12(2):126-151 · December 2015
DOI: 10.1504/WRSTSD.2015.073829
Abstract
The gasification of rice husks for small-scale
power generation in rice mills and other small
factories in Cambodia has spread rapidly in the
past decade and has a favourable investment
payback period where the facility is off-grid.
The technology is widely regarded as a
sustainable, low-carbon power option. However,
installed gasification technologies produce a
black waste water which is frequently disposed
of into the local environment without any
treatment. An analysis was undertaken to
identify and measure the key potential
contaminants and compare concentrations in the
water and sediment with regulatory thresholds
established in Cambodia and within other
jurisdictions. It was found that concentrations
of organic contaminants such as phenols and
benzene-type molecules (BETX) (water and
sediment) and polycyclic aromatic hydrocarbons
(PAHs) (sediment), as well as macro water
quality indicators, were far higher than
regulatory thresholds prescribe, posing threats
to sensitive aquatic ecosystems into which such
waste is introduced.
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--
Peter Davies
Managing Director
ID Gasifiers Pty Ltd
Delegate River, Victoria
Australia
Ph: 0402 845 295
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