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From: "tvoivozhd" <tvoivozd AT infi.net>
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Subject: Re: Sascha---you out there somewhere?
Date: Sun, 24 Jun 2001 12:32:55 -0700
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----- Original Message -----
From: Sascha <mrk AT sombor.com>
To: Homestead mailing list <homestead AT listserv.unc.edu>
Sent: Sunday, June 24, 2001 4:28 AM
Subject: Re: Sascha---you out there somewhere?


> I am here,my communication lines are still open for the homestead
> list,but  I have not much time right now.Fighting for survival takes most
> of my energy these days,but I am achieveing some progres.
> Thanks for the link it is interesting,but I have the impression that the
> gay is interested in industrial exploatation of his proces more than
> sharing the secret with ordinary peple like myself.
> But I want to ask about the sawdust burner you mentioned in another
> post,can it be used for burning other kind of biomas like the sunflower
> husk leftover ?
>
> Cheers,
> Sascha

tvoivozhd---yes, but you would have to run the husk through a
chipper-shredder----the type with a curved steel screen that you can remove
and put back in.  Different screens have different size openings to control
particle size.

There used to be one made by Kemp Mfg., Erie, Pennsylvania with some good
features, some bad.  It had a spring-loaded rock-ejector door and several
screens---good.  It had a high center of gravity, and a solid rotor---bad.
Tipped over easily and the solid rotor had to be cleared of jams often.
Five horsepower engine which isn't really adequate---an eight or nine
horsepower is the minimum I prefer.  It also had no clutch of any type, so
was harder to start.

I also had an old WW Grinder, like Kemp, one of the earliest for home use.
It also had a five horsepower engine, which wouldn't handle stalks from my
banana grove, and a solid rotor.  It worked well with an eight horsepower
engine, and it also was made of cast iron, which is much more durable than
the sheet metal used in MTD and other cheap brands of chipper-grinders.

A rotor with swinging hammers is much better.  Instead of stopping when an
overload of material threatens to jam the rotor, the hammers swing back and
slowly gnaw away at the overload until it is worn away. A centrifugal clutch
or tension-roller on the drive belt also makes the engine easier to start.

The particles from sunflower husks would be less dense than sawdust, so some
adjustment for that might have to be made in the sawdust burner air-supply,
or if it uses a feed auger, in the auger speed.  I suspect sunflower husks
would burn more completely and use less ash, which is helpful. Also for long
firing chamber life it would probably have to be lined with fire brick.
You might want to turn the sunflower particles into a briquette by a piston
press somewhat like a hydraulic or flywheel-type metal stamping
machine---use any cheap starch for a binder, potato, spoiled grain--even
lignin if the pressure in the stamping dies is high enough.

There are other sources of plans for a sawdust burner:

http://www.potters.org/subject37636.htm  (this is intended for firing
ceramics).
http://www.potters.org/subject37559.htm  (a modification of the above design
to avoid clogging)
http://www.potters.org/subject07829.htm  (more sources and useful
information)
http://vwww.netcom.net.uk/~n/nri/pfrp/r5073.htm  (reference to sawdust
suspension burners---I don't know what this means---probably that the
sawdust grains are suspended by an air blast from below where they enter the
firing chamber)
http://www.dantrim.com/  (some ideas from a sophisticated Danish pellet
burner manufacturer)
http://keenjunk.com/_junkyard/jp0007_5.htm  (see the section on radial
blowers---you can feed dry sawdust or dry sunflower granules right through
the blower into the fire chamber.  Note for really small scale
experimentation you can use something as small as a hand-held hair dryer to
supply forced air---a squirrel-cage furnace blower for something larger, but
don't feed sunflower granules through them, that requires a radial blower)

http://www.videncenter.dk/uk/yellow.htm  (use of automatic stoker as part of
pellet or chip
stove)

http://solstice.crest.org/renewables/stoves-list-archive/msg01152.html
(cheap briquetters using any poor quality, cheap starch as a binder are made
and sold in Calcutta, India)

http://bioenergy.ornl.gov/  (U.S. Govt information, links on bioenergy)

http://www.ikweb.com/enuff/public_html/Stoves.html  (a gasifier is really a
type of a biomass-burning stove.  This is a fine compendium of gasifier and
stove information.  See the English Big Top gasifier for a cheap, simple,
efficient gasifier to run a a truck or engine-generator. Something on a
briquetting machine too)

http://www.fao.org/docrep/T0275E/T0275E05.htm  (making biomass pellets or
briquettes)
WOOD PELLETS

Wood pellets are a comparatively new and attractive form of fuel. When you
burn wood pellets, you are utilising an energy resource that would otherwise
have gone to waste or been dumped in a landfill. Pellets are usually made
out of waste (sawdust and wood shavings), and are used in large quantities
by district heating systems. The pellets are made in presses, and come out
1-3 cm long and about 1 cm wide. They are clean, pleasant smelling and
smooth to touch. Wood pellets have a low moisture content (under 10% by
weight), giving them a higher combustion value than other wood fuels. The
fact that they are pressed means they take up less space, so they have a
higher volume energy (more energy per cubic meter). The burning process is
highly combustible and produces little residue. Some countries have exempted
pellet appliances from the smoke emission testing requirements.
There are different kinds of pellets. Some manufacturers use a bonding agent
to extend the life of the pellets; others make them without it. The bonder
used often contains sulphur, which goes up the chimney on burning. Sulphate
pollution contributes to acid rain and chimney corrosion, so it is best to
buy pellets without a bonding agent.
Wood pellets characteristics:
Diameter : 5 - 8 mm
Length  : max. 30 mm
Density : min. 650 kg/m3
Moisture content : max. 8% of weight
Energy value : 4,5 - 5,2 kWh/kg
2 kg pellets = 1 litre of heating oil

And a gasifier incorporated in a pellet stove which burns the generated
producer gas in a secondary chamber is the most efficient use of biomass
fuel, and emits the lowest level of pollutants.




The Combined Use of Perennial Grass Biofuels and Gasifier Pellet Stoves and
Furnaces as a Greenhouse Gas Offset Strategy


R. Samson, P. Girouard, B. Mehdi Resource Efficient Agricultural
Production-Canada Box 125, Ste. Anne de Bellevue, Quebec, H9X 3V9

M. Drisdelle, C. Lapointe Dell-Pointe Technologies, Blainville, Quebec, J7C
2Z6

R. Braaten CANMET Advanced Combustion Laboratories, Natural Resources
Canada, Ottawa, KIA OGI

S. Hall Macdonald Campus of McGill University, Ste. Anne de Bellevue,
Quebec, H9X 3V9


Abstract
Recent advances in biomass feedstock development and conversion technologies
have created opportunities for using agricultural land as a means of
producing renewable fuels. Closed loop biomass production in the form of
perennial grass has been identified as a near carbon neutral energy cycle
with significant energy production potential for the Canadian economy. These
grasses can abate greenhouse gas emissions by increasing carbon storage in
the landscape, as well as by displacing fossil fuels in combustion
applications. Current research includes optimizing the fuel pelleting system
of these grasses in order to facilitate the handling and enduse conversion.
The development of the world's first gasifier pellet stove by
DellPoint/CANMET has created new opportunities for using pelleted
agricultural fuels, particularly perennial grasses. The gasifier pellet
stove technology has provided energy end-use efficiencies of 81-87%, which
represents a significant improvement compared to the first generation
systems. The efficient production and conversion of the grasses represents a
strong net energy chain. The warm season (C4) grass, switchgrass, holds much
potential due to its high yields and modest ash content, as well, it has an
estimated energy output:input ratio of 20: 1. The opportunity for offsetting
greenhouse gas emissions are particularly attractive for Eastern Canada,
where fossil fuel prices are generally higher and electrical heating of
homes is widespread. Every I million hectares of switchgrass contains the
equivalent energy of 30 million barrels of oil. High yielding closed loop
biofuels harbour a potential for assisting Canada in meeting its climate
change commitment, while also stimulating rural development and export
market opportunities.

Introduction
In order for biomass fuel production and utilization systems to become a
major supply option in helping the world make the transition to a
sustainable energy economy, modernization is required. Many renewable energy
sources such as hydro, wind and solar can be used for electricity
generation. Biomass fuels are also well suited to economically reduce
greenhouse gas emissions from our heating and transportation related energy
needs. Canada is well positioned to become a major contributor to greenhouse
gas reduction in the global economy via dedicating a significant portion of
its surplus agricultural land base for biofuel production. This could be
used to help not only Canada in meeting its greenhouse gas emission
reduction targets, but also to assist European and United States reduction
targets, through the use of highly productive closed carbon loop biomass
fuels replacing fossil fuels and through increases in carbon storage in
agricultural landscapes resulting from the production of these crops.

Since 1991 REAP-Canada has been working with farmers and scientists to
develop and evaluate perennial grasses as a means to economically capture
and store solar radiation. Working relationships have also been developed
with industry partners to convert these feedstocks into economical energy
applications.

Greenhouse gas mitigation may offer the potential to create new domestic and
export market opportunities from Canada's agricultural sector as well as
energy efficient end use technologies. This paper will outline the
possibilities offered by growing perennial grasses for biofuels and
converting them into space heat using the Dell-Point close-coupled gasifier
pellet stove.

Perennial Grasses: Economical and Efficient Solar Collection from Plants
Fast growing perennial grasses are ideal candidates for biomass production
as they have lower maintenance costs and are more efficient at storing solar
radiation during the growing season than annual crops. Perennial grasses are
also better adapted to marginal soils, which have low opportunity costs for
agricultural production. In 1991, results by the US Department of Energy,
and feedback from farmer cooperators, led REAP-Canada to initiate a biofuel
feedstock development program focussed on grasses. The program has received
eight years of continuous support from Natural Resources Canada. The results
(ref 1, ref. 2) from the program indicate these crops: 1) result in the
highest net energy production per hectare; 2) have the lowest cost of
production of all dedicated energy feedstocks; 3) increase carbon storage in
the landscape compared to annual crops.

Warm season grasses have further been identified to have biomass quality
advantages for improving combustion efficiency compared to agricultural
residues which include lower silica, potassium and chlorine contents (ref,
3). The typical ash content of overwintered C4 perennial grasses is 3%,
while that Of C3 perennial grasses is 6%, and cereal residue is 7-10%.

In Eastern Canada, warm season (C4) grasses, such as switchgrass, have
obtained the highest biomass yields relative to the rest of the country
(8-13 odt/ha). C4 photosynthetic mechanisms use only one half as much water
per tonne of biomass produced, which contributes to a higher yield potential
than C3 species, such as willows and timothy (ref 4). In cooler regions
where switchgrass is not well adapted, other C4 perennial grasses with
higher cold tolerance are in need for further evaluation and development.
Alternatively, in cooler regions, productive C3 grasses, such as reed canary
grass can be used if combustion equipment and markets will accept the higher
ash fuel contents of these grasses.

In the case of switchgrass, late maturing grasses, which have longer periods
of solar radiation collection, were found to produce the highest yields (ref
5). Further yield increases up to 15 t/ha can be realistically achieved in
Eastern Canada via an aggressive plant-breeding program. Development of
these high yielding perennial grasses could enable a diversification of
Canada's energy economy and create export opportunities. The crop appears to
have an excellent energy output to input ratio of approximately 20: 1, while
annual crops, such as wheat or corn, are at approximately 5:1. Switchgrass
is also relatively dry (<15% moisture) at the time of baling and its
moisture content further declines with proper storage. Switchgrass contains
approximately 18.4 GJ of energy per dry tome (ref 6), which is slightly
lower than wood. A yield of 10 t/ha represents the energy equivalent of
approximately 30 barrels of oil, assuming a barrel of oil contains 6090 MJ
of energy.

The current cost of warm season grass production is $41-$68 per dry tonne
(costs depend on the yield and the time of harvest (ref 2)). When
switchgrass is used to manufacture pellets, it requires little or no drying.
A survey of wood pellet producers in the United States indicated the average
cost of wood residues and drying for pellet manufacturing to be $46.29 (ref
7). With increased demand for forest residues since the time of the survey
(1994), current prices for wood wastes and drying in some regions are now in
the range of switchgrass production costs. In contrast to wood and fossil
energy prices, prices of agricultural commodities have a long-terrn trend of
slowly declining in real dollars. The economics of growing biofuels will
become increasingly attractive, particularly if a strong research and
development effort is implemented.

Creating Energy Efficient End Use Technologies for Biomass
It is obvious perennial grasses will not create a transition in our energy
economy in the short term unless they are used in energy efficient end use
technologies. For example, switchgrass at $50 tome holds little potential
against $40/tonne for coal as an electricity generating fuel, given that
coal contains a third more energy and has a much higher energy density.
However, new energy efficient end use technologies such as cellulosic
ethanol are being developed for biomass crops. One of the most interesting
combustion applications is the conversion of the grasses into fuel pellets
for use in pellet stoves and furnaces that are able to efficiently bum
higher ash containing fuels.

Recognizing the long term market potential for growth in the pellet industry
would be from agricultural biomass and higher ash wood residues (such as
bark), Dell-Point Technologies established a partnership with the Natural
Resources Canada advanced combustion laboratory to explore this opportunity.
The goal was to create a high efficiency, low emission, pellet stove capable
of burning higher ash fuels than tolerated by most equipment on the market.
The result

was the licensing of a close coupled gasification technology pellet stove in
1998. The technology has an overall efficiency of 81-87% which compares
favourably to the more modest efficiencies of 35-70% with most stoves on the
market. Normally, combustion of higher ash fuels can cause slag and clinker
as the silicate in the ash initially starts to melt at around 600 degrees
Celsius. The design of the close couple gasifier technology is such that a
lower operating temperature exists in the bottom of the gasifier where the
first stage of the combustion occurs, causing the ash to simply fall through
the grate and into the ash pan. The resulting gases are then super combusted
as they leave the burner, resulting in near complete combustion. The design
of the Dell-Point close coupled gasifier technology, enables excess air
levels to be used that are 7 times lower than current technology, which is
the basis of the high stove performance. A furnace is currently under
development.

Economics of Heating with Pelleted Closed Carbon Loop Biofuels
In Canada, biomass can probably play its most important role in reducing
fossil fuel emissions in Eastern Canada where limited supplies of natural
gas, oil and coal create higher heating costs. As well, there exist other
opportunities for expanding the export of pellets into Europe. In 1999, four
Canadian pellet producers will export approximately 100,000 tonnes of
pellets in bulk, which represents almost 10% of North American production.

In the market of Eastern Canada, pellet stoves can economically replace
electrical or propane heating of homes in Ontario, Quebec and the Maritimes.
There are many opportunities for displacement of electrical heating
particularly in Quebec, where approximately 50% of homes are heated with
electricity. This high level of electrical heating is unique in a northern
climate. Heating with pelletized agricultural and forest residues using the
new gasifier pellet stove technology could save consumers money while
enabling Quebec to export its existing electricity production to displace
coal generating electrical plants in Ontario, New Brunswick and the US
Northeast. The analysis in Table I indicates that consumers 'in the Montreal
region of Quebec would save approximately 1/3rd of their energy costs by
using pellets, compared to electricity, and would have similar heating costs
to oil.

Greenhouse Gas Emissions
Unlike fuel heating costs, the relative C02 emitted into the atmosphere of
the three systems varies dramatically (Table 2). Switchgrass pellets are
able to heat houses with 1/10 the C02 emissions of homes heated with
electrical energy from coal and 1/4 the C02 emissions of oil heated homes.
Emissions using switchgrass would be reduced by 98.3% and 95.2% compared to
electricity (from coal) and heating oil, respectively given that renewable
energy was used for electricity generation for the pellet plant, instead of
coal. This could become the case, if electrical energy was not used in home
heating in some provinces, such as Quebec.

Reducing Cost in Pelleting Operations
Cost reduction in producing pellets and supplying pellets needs to be a
priority for the development and further expansion of pellet fuel heating. A
1994 survey of pellet manufacturers indicated that raw material, energy,
labour and bagging costs were the largest costs associated with pellet
production (Figure 1) (ref 7). The survey also indicated 48% of pellet
producers to have experienced raw material supply shortages and producers
being concerned about rising feedstock costs. The production of high
yielding biomass feedstocks such as switchgrass could help stabilize
feedstock costs and reduce drying costs. Other needs of the pellet industry
are to develop higher throughput pelleting technologies, and bulk delivery
systems to help reduce labour, bagging, and plant maintenance costs.

Preliminary pilot plant research by Dell-Point Bioenergy Research and
REAP-Canada indicate switchgrass to have similar pelleting properties to
alfalfa (which is commonly pelleted for the livestock feed industry).
Throughput estimates were 80-100 pounds per Hp for switchgrass compared to
established values of 20 lbs per Hp for hardwood and 40 lbs for softwood
(ref 8). This could reduce pellet fuel costs considerably as throughput on a
typical 150 Hp pellet machine would increase to 12.4-15.5 tomes per hour in
the case of switchgrass, compared to 3.1 and 6.2 tonnes per hour in the case
of hardwood and softwood sawdust. Further testing is required in commercial
pellet plants to better assess these estimates and determine accurate pellet
production associated costs.

Future Directions
The current agri-fuel pellet project partnership aims to commercialize
closed loop agricultural biofuels as a practical and economical solution to
help reduce greenhouse gas emissions. Optimization of the production of
perennial grass fuel pellets has now been initiated to examine means of
reducing the fuel chain costs, from field to final space heating costs. This
work will entail harvesting, storage, comminuting, pelleting, delivery and
finally burning in the Dell-Point pellet furnace and stove.

These initiatives along with improvements in biomass feedstock development
through plant breeding could enable pelleted biofuels to become a low cost
contender in the search for greenhouse gas offset strategies in temperate
regions. Canada is well positioned to take advantage of this opportunity: it
has existing expertise in pellet production and combustion stove technology,
it has a proven record to produce low cost commodities on its large
agricultural land base and it is well positioned to expand export of
pelleted biofuels into the US and European markets.



References


I . Samson, R., Girouard, P., Omielan, J., Chen, Y. and Quinn, J.;
"Technology Evaluation and Development of Short Rotation Forestry for Energy
Production: Final Draft Report"; PERD Program, Natural Resources Canada and
Agriculture Canada. DSS contract 23440-2-9493/01-SQ; p.215; 1995

2. Girouard, P., Samson, R., Zan, C and Mehdi, B.; "Economics and Carbon
Offset Potential of Biomass Fuels, Progress Report"; PERD Program, Natural
Resources Canada, Contract 23341-6-2010/00 1/SQ pp. 120; 1998

3. Samson, R. and Mehdi, B.; "Strategies to reduce the ash content of
perennial grasses"; Expanding Bioenergy Partnerships, Bioenergy 98, Great
Lakes Regional Biomass Energy Program, Chicago, Illinois; pp 1124-113 1;
1998

4. Samson, R. and Chen, Y.; "Short-rotation forestry and the water problem";
Proceedings of the Canadian Energy Plantation Workshop, Natural Resources
Canada, Ottawa Ontario; pp.43-49; 1995

5. Madakadze, I.C., Coulman, B.E., Peterson, P., Stewart, K.A., Samson, R.
and Smith, D.L.; "Leaf area development, light interception, and yield among
switchgrass populations in a short-season area."; Crop Science Vol. 38, pp
827-834; 1998

6. Mclaughlin, S.B., Samson, R., Bransby, D. and Wiselogel, A.; "Evaluating
physical, chemical, and energetic properties of perennial grasses as
biofuels"; Proceedings of the Seventh National Bioenergy conference. Volume
2. September 15-20, Nashville. Tennessee, pp 1-8; 1996

7. Council of Great Lakes Governors; "Wood Pelletization Sourcebook"; pp 41;
Great Lakes Regional Biomass Energy Program; 1995

8. Samson, R., Girouard, P., Mehdi, B., Drisdell, M. and Lapointe, C.;
"Assessment of Pelletized Biofuels: Annual Report" PERD Program, Natural
Resources Canada, Contract 23348-8-3145/001/SQ; April 1999.

9. Natural Resources Canada.; "Heating with Oil, Home Heating and Cooling
Series"; Book #4; p. 58; 1997

10. NOVEM.; "Pretreatment technologies for energy crops"; Biomass Technology
Group, Enschede; The Netherlands; p. 98; 1996

11. Girouard, P., Walsh, M.E. and Becker, D.A; "BIOCOST-Canada: A new tool
to evaluate the economic, energy, and carbon budgets of perennial energy
crops"; Fourth Biomass Conference of the Americas, August 29-September 2,
Oakland, CA.; 1999 In Press



Tables and Figures


Table 1. Fuel Costs of Home Heating in Quebec with Electricity, Pellets and
Oil
  Electricity
   Pellets
 Heating Oil

Fuel Cost
 5.97 cents/kWh
   $180/tonne
 35.00 cents/litre

    wood

Raw Fuel Cost after taxes (7% GST, 7.5% TVQ)
   6.87 cents/kWh
 $207/tonne
 40.26 cents/litre

Cost/GJ
 $19.24
 $10.45
 $10.53

Cost/GJ after conversion

(95% electricity, 85% pellets, 85% oil)
   $20.25
 $12.29
 $12.39

Cost to heat a new detached 2000 sq. ft. home in Montreal
   $2025
 $1229
 $1239


Note 1. Wood Pellets are assumed to have an energy content of 19.8 GJ/tonne
electricity 3.6 MJ/kWh and oil 38.2 MJ/litre (ref 9). Switchgrass pellets
would have to sell at 7% less the cost of wood pellets, due to their
slightly lower energy value (18.4 GJ/tonne vs. 19.8 GJ/ tonne).

Note 2. The analysis does not include capital costs associated with
equipment.

Note 3. Heat requirement of home is 100 GJ (ref. 9)



Table 2. Relative C Emissions from electricity, switchgrass and heating oil
of heating a home with a 100 GJ heat demand
  Electricity
   Pellets
 Heating Oil

Net Heat required
 100 GJ
 100 GJ
 100 GJ

Energy Conversion Efficiency
 37% eff. Coal plant

95% household
   85% household
 85% household

Total GJ Energy Required to 284 GJ provide 100GJ delivered
 117 GJ
   117 GJ

Carbon emissions associated with each energy form
   24.7 kg C/GJ
 1.0 kg C/GJ
 22.3 kg C/GJ

C produced
 7015 kg C
 117 kg C
   2609 kg C

Total carbon emissions including chopping & densification of biomass
   7015 kg C
 685 kg C
 2609 kg C


Note 1. Assumes 6.4 tonnes of switchgrass pellets consume 5.76 GJ of energy
(900MJ/t) for chopping and 2.56 GJ of energy (400 MJ/tonne) for pelletizing
(ref. 10). Electrical energy for chopping and pelletizing from coal.

Note 2. Switchgrass production emissions range from .89-1.05 kg C/GJ (ref.
11).

Note 3. Some additional energy costs may be incurred in operating the
combustion appliances



Fig. 1 Breakdown of Costs Associated with Pellet Manufacturing

If you can paste all this in your browser, the graphics on the cost
breakdown is displayed as part of the above article.


http://www.reap.ca/Reports/The%20combined%20use%20of%20perennial%20grass%20b
iofuels%20and%20gasifier%20pellet%20stoves%20and%20furnaces%20as%20a%20green
house%20gas%20offset%20strategy.htm