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Dear Fred, Dick,
Tom, Jane & All,
I agree with Fred
that sub-stoichiometric gasification of biomass is a good replacement for coal
as a technical innovation. However, when we compare the effective unit cost of
energy from coal combustion and biomass gasification, replacing the first with
the second may not be economically attracfive particularly considering the
capital investment on gasifiers.
Much more economic benefits accrue by replacing
costlier liquid fossil fuels such High Speed Diesel,LDO &FO with
producer gas. The pay back period depends on the number of hours the plant is
annually operated. For instance, we installed a 300 kg/hr biomass gasifier
(based on IISc technology) at a Heat Treatment facility in Tamilnadu,
India, which replaces LDO consumption of about 100 lt/hr. The plant
operates on 100 % gas basis using Casuarina feedstock and has clocked more than
5,000 hrs of operation, averaging about 20 hr/day. The plant cost was
paid back within an estimated period of less than one year. Had the
facility been using coal instead of LDO, the pay back period would have exceeded
5 years !!
We are in the
process of implementing a Megawatt Class grid connected power project. The
plant, expected to be commissioned shortly, will gasify coconut shell to
annually generate about 7 Million kWhs of electricity and 400 MT of
Activated Carbon as a by-product. Since the same plant is used to manufacture
both products, the unit cost of manufacturing each product is a fraction of the
cost from the Electricity Utility and other Carbon manufacturers resp.
Dick's aversion to
biomass combustion is intriguing. All processes based on biomass utilisation are
essentially CO2 neutral. Any leaking methane from anaerobic digestion has a much
higher GHG index than CO2.
As for digestion,
it is admirably suited to high moisture and fibre content biomass such as
chicken litter, cattle dung, food waste and fibrous plants. Its suitability to
woody biomass (particularly the high yielding C4 varieties) needs investigation.
Firstly, woody biomass contains significant fractions as lignin which does not
easily get digested, reducing yield and increasing cost. Secondly, it needs
further pre-processing adding to costs. The yield varies with the seasons and is
at best a dubious source of energy for industry.
I agree with Tom
that there is urgent need to concentrate on principles and conversion first than
on materials and resource. Biomass resource availability is not at all a serious
issue even in far Northern latitudes, where countries like Sweden &
Denmark meet a substantial proportion of their energy needs from
biomass.
Biomass
gasification is no longer a lot of hot air. It gives us a special glow of
satisfaction to see it ignite interest in cost conscious industrial units.
Regards.
T R
Krishnaswamy
Energreen Power
Ltd.,
# 2/1, North
Avenue,
Srinagar
Colony,
Saidapet,
Chennai, Tamil
Nadu
India - 600
015
Tel : 91(44) 2301231,
2201840.
e-mail : energreenpower@
lycos.com
----- Original Message -----
Sent: Friday, May 24, 2002 8:28 PM
Subject: Re: Improvement of energy crop
yield
In a message dated
5/24/02 9:40:05 AM Eastern Daylight Time, dglickd@pipeline.com
writes:
Changing focus from wood and/or waste in northern climes,
biomass grown in
tropical and semi-tropical regions, used directly as
feedstocks for
anaerobic fermentation that produces both methane rich gas
and
compost-fertilizer -- both energy products on a global scale,
together with
focusing on locations without indigenous energy resources
provide sound
economic bases for concentrating on improving biomass
yields as well as
species developments.
I completely agree with Dick, here. Our work has shown
that biomass is a great way to replace coal in coal-fired units -- but not by
sticking the biomass material into the boiler. We first have to gasify the
material -- and this can be done economically -- before firing the gas in the
boiler.
We don't like digestion, as we don't care for the waste
product. However, we have found that substoichometric gasification is quite
effective, provides a clean, flammable gas and replaces coal with great
alacrity when introduced into the boiler in the proper location.
This
has been shown to be a great way to get significant percentages of coal
reduced at specific power stations. Next on the agenda will be to translate
the system into 100% biomass fired (with all its attendant infrastructure
issues). We will be starting burn tests on this next month in Illinois.
Tom was correct in saying that biomass (compared to more energy dense
fuels) falls short. However, the Europeans -- and more recently some of us
colonists -- have shown that it can be a very effective fuel when introduced
into the combustion process properly.
Is it just me, or does it seem
to others that this topic is really catching fire of late? (No pun
intended.)
Regards,
Fred Murrell
Biomass Development
Company
Bradenton Florida USA
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