Tom and listers,
GC's are limited in their ability to detect broad ranging components. A
GC set up for fixed gases usually can't detect compounds like ethanol,
methanol, acetic acid which are all present in gasifier produced gases unless
specifically removed and acetic or other organic acids will contribute to
engine oil acidification and corrosion over time.
There are system that can provide instantaneous broad ranged gas
analysis going from hydrogen to whatever you want in MW.
The other question is to gas heating value for combustible components
to adjust the engine air/fuel ratio as it may change, such as change in
moisture content in feedstock, ambient humidity, composition of feedstock or to
increase the range of acceptable feedstock for improved economic performance.
There is such a device which is surprisingly inexpensive and effective with any
combustible component being analyzed instantaneously, which a GC cannot do.
Sincerely,
Leland T. "Tom" Taylor
Thermogenics Inc.
-----Original Message-----
From: Peter Davies <[email protected]>
To: gasification <[email protected]>
Sent: Mon, Jan 4, 2016 7:30 pm
Subject: Re: [Gasification] Characterization of waste water from biomass
gasification equipment: A case-study from Cambodia
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]
www.trmiles.com
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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