[Gasification] warm season grass pellets are ready to go!

[Roger Samson]

Tom and all

 

In Canada we are running out of sawdust and trees in Canada. We are
overharvesting the forests and the warm winters are causing the pine beetles
to decimate our productive west coast forests which will cause major fibre
supply problems in the longer term.. 

 

Ash is not a problem for commercial boilers for combustion. Coal of 7-20%
ash is commonly burned. Some of the boilers we are using for agri-fibre fuel
pellet combustion can burn coal or biomass. The greenhouse growers prefer
using agri-fibre pellets as they have less particulate load and can reach
higher temperatures for quick turn-up when temperatures get cold compared to
coal. 

 

Fall harvested switchgrass in Montreal contains 4.5-5.2% ash. Overwintered
switchgrass contains 2.7-3.2% ash. This is a much easier fuel to deal with
than coal in commercial boilers. The overwintering is the key to getting out
the chlorine and potassium to make them problem–free fuels. There are 25
greenhouses owners in Ontario using agri-fibe fuels (crop milling residue
pellets of oat hulls and wheat middlings). Some of them tried switched to
coal (to save money) from natural gas and then switched to agri-fibre fuel
pellets because they didn’t like babysitting their boilers. Coal is wet,
coal is dirty, you can’t use the coal ash on farm fields it goes to dumps
and coal is getting more expensive. Agricultural commodity prices have been
going down for 600 years. Some farmers also tried burning corn but switched
to agri-fibre fuel pellets as they are easier to light and produce less
particulates and you lose less heat driving off the moisture. Corn is 14-15%
moisture, agri-fibre pellets are 7-9%.  Crop milling residue pellets are
moderately low in chlorine and potassium.  They are not ideal, some boilers
may not handle even this level of corrosion potential over a longer term.
The best solution is to blend the wheat middling with overwintered
switchgrass. You get a binding effect from the starch in the wheat middlings
and very low K and Cl from the overwintered switchgrass.  About 25% of the
product from milling wheat is wheat middlings. That’s a lot of binder in
North America sitting in all those mills in North America.  

 

This year we will start planted commercial fields of switchgrass for use in
commercial boilers. Presently we have a problem in that the switchgrass
fields currently in production in Canada are at least 3 hours away from
existing alfalfa dehydration pellet or cubing plants. Farmers groups are now
planting grasses around these mills and others are looking at putting up
plants where switchgrass grows best.   As far as cubing, in Canada the
dehydration industry also seems to like the equipment of Cooper Industries
in Idaho  for herbaceous feedstock densification
http://www.cooperequipmentinc.com/. Alan Teel reports from Iowa they can
cube overwintered switchgrass but not fall harvested crop. It seems there is
some waxy-like surface condition on the fall harvested crops that make them
less conduce to agglomeration processes. Cubing is cheaper but pellets are
more readily accepted and used by the market. 

 

My recommendation is to forget co-firing unless it is a co-gen plant.
Farmers will be left in a state of penury if they have to sell biomass to
compete with coal for power generation.   Switchgrass in co-firing
applications converts at 30-35% efficiency but it converts at 85% efficiency
in modern boilers fro BIOHEAT. We believe farmers can earn about
$70-$80/tonne for direct bioheat applications. They plant developers want to
pay ½-2/3rds of that for other bioenergy conversion options currently
favoured by the US government.    

 

We are also working on strategies for the residential fuel market but this
is a longer term process. We are also working on a production guide for
farmers to get into bioenergy production. If anyone knows of any funding
support we would highly appreciate more support as this field looks highly
promising. We are doing our research work on a modest budget so we have
started providing consulting support to a number of projects in North
America. We believe all the appropriate conditions (high fossil fuel prices,
wood-like biomass feedstock chemical composition from grasses, and excellent
advances in boiler technology) are now present to makes the warm season
grass pellets industry a go. It’s the best chance for an immediate biomass
breakthrough in the North American energy market that is economically
competitive with fossil fuels. 

 

Roger Samson

www.reap-canada.com

 

  

  _____  

From: Thomas Reed [mailto:tombreed at comcast.net] 
Sent: Sunday, April 30, 2006 4:42 PM
To: Roger Samson
Cc: MMBTUPR at aol.com; Gasification at listserv.repp.org
Subject: Re: [Gasification] warm season grass pellets are ready to go!

 

Dear Roger:

I have believ that most grasses tend to be high in ash - (our book S. Gaur
and T. Reed "Thermal Data for Natual and Synthetic FUels", Marcel Dekker,
1998) lists switch grass, 1.8%; wheat straw 7.4%.  So the species seems to
be quite important.  Do you have other candidates?

  _____  

I have been trying a number of pellet species in my pellet stove this season
and cherry pits (1.4% ash) were acceptable, more ash cleanout than wood.
Distillers dried grains (6% ash) were awful.  My stove wouldn't burn corn.  

We have drifted into using 1/4 inch pellets, but I'm not convinced that that
is the best size.  I think 3/8 or even 1/2 inch would work in current stoves
and result in less die wear and power in the manufacture.

We need a good collection of experience on pellets and should all get pellet
stoves.  We are running our of sawdust. 

Tom Reed     BEF

Roger Samson wrote: 

Lewis
 
 
 
We are focusing on warm season grasses, cutting them late fall at freeze up,
overwintering them in the field to leach out the potassium and chlorine and
then pelleting  them using a low cost binder like wheat bran or a low cost
grain like rye (about a 10% mix you can try). It's even better if you can
access lighter soils for growing grasses as there is less silicic acid
uptake on sandy soils than clay soils. Less ash equals less wear. You can
also use 2% animal fat to reduce wear. The low N content of warm season
grasses makes them relatively inert to breakdown during the winter (They are
the preferred material for making straw bale housing).  
 
 
 
Our goal is to produce pellets with less than .1% potassium and 0.02%
chlorine. That way we have limited issues with corrosion or clinker. I think
this can be done in all the northern states of the US and all provinces of
Canada. The semi-arid regions may have some problems with leaching otherwise
it should work. 
 
 
 
Yes its time for the farmers to give the "hole diggers" a run for their
money. They are doing it in Brazil with cane ethanol, we can do the same in
North America and other temperate regions with warm season grass pellets.
 
 
 
Grass pellets have a fuel cycle energy output:input of 12-14:1, corn ethanol
is about 0.8-1.5:1.  That's the reason the subsidies are so high on corn
ethanol, the fuel cycle isn't decoupled from the fossil energy industry. 
 
 
 
I have burned straight overwintered switchgrass pellets in my gasifier
pellet stove in my house starting in the winter of 2004-2005.  They burn
without clinker and can be recommended. All it requires is emptying the ash
pan every other day. I have to mix fall harvested switchgrass pellets with
wood pellets to successfully burn them. This can also be done but fall
harvested material I think is more suitable to larger combustion systems and
blending with other fuels. 
 
 
 
In 2006 we are now working on how to reduce the ash content of fuels with
the goal of creating a wood pellet substitute for residential heating
applications.   However we still think the entry market is rural commercial
energy heating applications like greenhouses. 
 
 
 
Roger Samson
 
www.reap-canada.com
 
 
 
  _____  
 
From: MMBTUPR at aol.com [mailto:MMBTUPR at aol.com] 
Sent: Friday, April 28, 2006 10:56 AM
To: rsamson at reap-canada.com; MMBTUPR at aol.com; Gasification at listserv.repp.org
Subject: Re: [Gasification] [Gasificiation] Future Saudi oil production
 
 
 
          to     Gasification List                    from        Lewis L
Smith
 
Thanks to Roger Sampson for his encouraging comments on pelletizing.
 
I only have experience in evaluating one pelletizing system but remember
that die wear was a major issue, and that controlling this begins in the
field, with plant uptake from the soil and with what gets attached to the
plant in harvesting but which is not successfully removed in feedstock
preparation.
 
In Puerto Rico, we have a large fluidized-bed, coal-fired generating plant
which would be a good candidate for co-firing biomass pellets with coal. 
 
What has been the experience of Canada and other areas in this regard ?
 
Since combustion is a propagating process, I imagine that one issue is the
compatibility of pellet size with the size of the chunks of coal, but that
feedstock prep for fluidized bed should take care of this.
 
Cordially. End of message.
 
 
 
 
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