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July 17, 2009

David Dunn

Central Vermont Public Service

77 Grove Street

Rutland, Vermont 05701

RE: Assessment of Digested Cow Manure Solids for Densified Boiler Fuel

Dear Mr. Dunn:

We are pleased to enclose the final report on the assessment of digested cow manure

solids for densified boiler fuel. These preliminary results show that this material

cannot effectively be used as a boiler fuel due to issues around combustion. Several

case study examples are included that highlight some specific challenges to using

manure as a boiler fuel. Diluting the digested manure solids by blending it with

other biomass materials such as wood, however, would dramatically improve its

viability as a boiler fuel.

We have greatly appreciated the opportunity to collaborate with Central Vermont

Public Service and to research this topic in detail. If you have any questions or

require any additional information, please do not hesitate to call.

Sincerely,

Christopher Recchia

Executive Director

Encl.

PO Box 1611, Montpelier, VT 05601-1611 ph 802-223-7770 fax 802-223-7772 [email protected] www.biomasscenter.org


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FINAL REPORT

Assessment of Digested Cow

Manure Solids for Densified BoilerFuel

Prepared for:

David Dunn


Rutland, Vermont

July17, 2009


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BERC Assessment of DMS for Boiler Fuel July 17, 2009 1

EXECUTIVE SUMMARY.............................................................................................................. 3Project Overview ...................................................................................................................... 3DMS as a Boiler Fuel................................................................................................................. 3Feasibility of Electrical Generation and Heating with DMS.................................................. 4Case Studies............................................................................................................................... 4Conclusions................................................................................................................................ 4

INTRODUCTION......................................................................................................................... 6Project Overview ...................................................................................................................... 6Central Vermont Public Service.............................................................................................. 6Biomass Energy Resource Center ........................................................................................... 6Scope of Study........................................................................................................................... 6Methods...................................................................................................................................... 7

CVPS COW POWER FARMS ..................................................................................................... 8Montagne Farm ......................................................................................................................... 8Green Mountain Dairy .............................................................................................................. 9Blue Spruce Farm ..................................................................................................................... 9St. Pierre Farm........................................................................................................................ 10

DIGESTED MANURE SOLIDS FUEL PROPERTIES .............................................................. 11DMS AS A FUEL ......................................................................................................................... 13

Processing DMS into a Useable Fuel..................................................................................... 13Drying DMS.............................................................................................................................. 13

Rotary Drum Drying ................................................................................................. 14Air Drying................................................................................................................. 15

Natural Air Drying .............................................................................................................. 16Enhanced Air Drying ............................................................................................................ 16

DMS Densification................................................................................................................... 16

Densification Methods............................................................................................... 16Uses and Markets for Densified DMS ........................................................................ 17Test Densification...................................................................................................... 18

COMBUSTION ........................................................................................................................... 19Combustion Options............................................................................................................... 19Combustion Technologies...................................................................................................... 19

Stoker Systems .......................................................................................................... 19Pneumatic Fuel Injection Suspension Combustion ..................................................... 19

Mineral Fusion During Combustion ...................................................................................... 19Combustion Emissions ........................................................................................................... 20

Potential Emissions from DMS Combustion.............................................................. 20Emissions Rates from Wood Combustion .................................................................. 21

FEASIBILITY OF ELECTRICAL GENERATION FROM DMS COMBUSTION SYSTEM .. 22Electrical Generation Technology......................................................................................... 22Potential for Electrical Generation ....................................................................................... 22

CASE STUDIES OF EXAMPLE PROJECTS ............................................................................ 24Manure Pelletization for Fertilizer........................................................................................ 24


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Promest BV: Helmond, Netherland ........................................................................... 24Perdue-AgriRecycle: Seaford, Delaware...................................................................... 24

Manure Briquetting................................................................................................................. 25Cow Manure for Combustion ................................................................................................ 25

Weise Farms: Greenleaf, Wisconsin ............................................................................ 25Eagle Creek Wholesale: Portage County, Ohio........................................................... 26

Others ...................................................................................................................................... 27CONCLUSIONS ......................................................................................................................... 28APPENDICES

Appendix A. Ultimate and Proximate Analysis

Appendix B. Mineral Composition Analysis

Appendix C. Pellet Fuels Institute Table of Pellet Fuel Quality Specifications

Appendix D. Mars Minerals Test Pelletization Report


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EXECUTIVE SUMMARY

Project Overview

Central Vermont Public Service (CVPS) launched the Cow Power program with the installation of

an anaerobic digester at the Blue Spruce Farm in Bridport, Vermont in 2004. Since then CVPS hassigned on five more farms that are currently producing electricity. The biogas from the digester

fuels engine gen-sets while the digested manure is passed through a solids separator. Liquids are

diverted to a lagoon and stored for periodic land application as part of the farms nutrient

management program. Solids from the separation process are used as a bedding substitute to

sawdust. This study explores the potential for these digested manure solids (DMS) to instead be

used as a boiler fuel.

DMS as a Boiler Fuel

DMS is significantly different from typical raw dairy manure. Two main factors make DMSfavorable for use as a biomass combustion fuel: it has been de-watered and many of the problematic

nutrients have been removed with the water. The material sampled has a sufficient energy value of

7,883 Btu per dry pound (only 5 percent less than typical wood fuel). While DMS is comparatively

better suited for both densification and combustion than raw manure, it still faces numerous

challenges. The dewatered manure solids have nearly ten times the amount of ash content as typical

wood fuels. Higher ash fuels can present issues such as slagging and fouling of ash material when

combusted. (Most biomass combustion equipment manufacturers design their systems to handle a

maximum of 6 to 7 percent ash content.) Also the remaining nutrients, especially nitrogen and

sulfur could present significant emissions issues.

The dewatered solids have a very high moisture content averaging 65 percent. Considerable drying

is necessary before the material can be densified, and some drying is required to burn the loose

material directly. The material also has a high concentration of relatively large fibers (100 percent of

DMS were between 10 45 mesh) due to the fact that many of the small fibers are removed in the

dewatering process, making it necessary to further grind the material before it can be densified.

Despite this minor challenge, with the proper conditions of moisture content, pressure and heat, a

durable pellet can be produced. However, other densified form factors such as larger tablets or

briquettes may prove more feasible given the materials characteristics. Also blending the dewatered

manure solids with other fibers such as grass or sawdust could achieve more desirable physical

properties for pelletization.

Drying the digested manure solids from 65 to 5 percent as needed for densification would require

tremendous amount of energy and would dramatically reduce the net energy assuming the DMS

were used to fuel to drying process. BERCs calculations indicate that as much as 16 percent of the

materials energy value (on a dry matter basis) would be used to dry the DMS for densification. The

best option for consideration is drying to 45 percent moisture, using 12 percent of the materials

energy value, for direct use as loose boiler fuel.


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Feasibility of Electrical Generation and Heating with DMS

Given the volumes of digested manure solids beyond the farms bedding requirements most farms

had insufficient amounts of possible boiler fuel to fire a large enough steam boiler to warrant

electrical generation using steam turbine technology (St. Pierre farm, the largest of the four farms,

would generate a maximum of 121 kWh of electricity). It should be noted that while there isinsufficient volumes of fuel to power a larger enough steam boiler to produce electricity, there is

enough fuel to run a smaller boiler that could help meet the farms thermal load. If the farms no

longer recycle the digested manure solids as bedding and the volumes generated increased

significantly (more than 15,000 wet tons per year), further analysis of feasibility of steam boiler and

turbine systems may be advisable. If the farms have distinct thermal loads that could be met using

smaller hot water boilers, the detailed feasibility of using the digested manure solids should be

examined.

Case Studies

Many equipment manufacturers claim they are able to effectively burn cow manure as a boiler fuel.

However, there are practically no installed systems in the United States at this time. Perhaps the

only known system in the US that has attempted to burn dried cow manure on a large-scale is the

Weise Brothers Farm that installed a manure drying system, a 400 horse power high pressure steam

boiler, and 600 kW steam turbine at their farm in Greenleaf, Wisconsin. The 1,600-cow farm

incinerates most of its manure to produce enough electricity to power 700 homes. Unfortunately,

since the system was first installed and throughout its operation, it has been plagued by numerous

issues most of which stem from using cow manure as a boiler fuel. Eagle Creek Wholesale in

Portage County, Ohio heats 3.5 acres of greenhouse space with manure, but supplements with

sawdust and woodchips.

Conclusions

Unlike the cow manure being burned at the Weise Farm in Eastern Wisconsin, the digested manure

solids produced by the Cow Power Farms has been dewatered and many of the nutrients and

minerals that cause slagging and fouling when combusted are not present. Without any successful

systems using cow manure to learn from, it is difficult to definitively conclude whether this material

can be used as a boiler fuel. In the absence of successful projects, BERC relied upon the laboratory

analysis and the experience and knowledge of solid fuel combustion experts.

The data gathered and examined as part of this study suggest that the digested manure solids can be

used as a boiler fuel and that the material could provide further energy value. However, the high

moisture and ash contents can present challenges for combustion and maintenance.

Given the relative small volumes of DMS produced, the possible technical difficulties of

combustion, the overall nutrient and soil amendment value of composted DMS, and the abundance

of inexpensive and cleaner burning solid biomass fuels (such as woodchips and wood pellets), the


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viability of DMS as a densified fuel for on-farm energy production or off-farm pellet fuel sales is

limited.


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INTRODUCTION

Project Overview

Central Vermont Public Service (CVPS) launched the Cow Power program with the installation of

an anaerobic digester at the Blue Spruce Farm in Bridport, Vermont in 2004. Since then CVPS hassigned on five more farms that are currently producing electricity. Biogas from the digester fuels

engine gen-sets, while the digested manure slurry is passed through a solids separator. Liquids from

the dewatering process are diverted to a lagoon and stored for periodic land application as part of

the farms nutrient management program. Solids from the separation process are used as a bedding

substitute to sawdust. However, several of the farms generate more digested manure solids (DMS)

than is needed for bedding the cows. This presents an opportunity to study potential on-farm uses

for this material. CVPS hired BERC to explore the potential for using digested manure solids as a

boiler fuel.


Central Vermont Public Service (CVPS) is an independent, investor-owned electric utility providing

energy and energy-related services to customers in nearly three-quarters of the towns, villages and

cities in Vermont.

Biomass Energy Resource Center

The Biomass Energy Resource Center (BERC) is an independent, national nonprofit organization

located in Montpelier, Vermont with a Midwest office in Madison, Wisconsin. BERC assists

communities, colleges and universities, state and local governments, businesses, utilities, schools,and others in making the most of their local energy resources.

BERC is a project-focused organization whose mission is to achieve a healthier environment,

strengthen local economies, and increase energy security across the United States through the

development of sustainable biomass energy systems at the community level. BERC's particular

focus is on the use of woody biomass and other pelletizable biomass fuels.

Scope of Study

BERC was hired by CVPS to examine the feasibility of using digested manure solids (DMS) fromthe digester systems from four of the CVPS Cow Power farms as a boiler fuel. This assessment

consists of three main components: a review of any existing similar projects using manure as fuel,

evaluation of the materials suitability for densification, and a review of the materials fuel

properties. While many options for blending DMS with other biomass materials (wood fibers,

grasses, etc.) exist and could possibly help improve the viability of DMS as an effective boiler fuel,

comparing the numerous blends was not part of the scope of this study.


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Methods

BERC conducted a detailed review of the literature and contacted national manure management

experts and renewable energy equipment vendors to identify any existing technologies,

commercially available equipment, and existing operations that use dairy manure as a boiler fuel.

BERC visited the four farms, interviewed the farm owners, and gathered samples for densificationtrials and for laboratory analysis. DMS samples were shipped to a pelletization laboratory in

Pennsylvania and brought to a local bench-scale pellet mill for test densification. Additional samples

were shipped to a national laboratory in Colorado which specializes in analyzing biomass fuels.

Laboratory and densification results were analyzed and our findings are summarized in this report.


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CVPS COW POWER FARMS

While the number of farms that are participating in the CVPS Cow Power program is increasing,

four dairy farms with digesters and dewatering equipment were selected for this study.

The following tables give basic background information on the four farms that were examined aspart of this study.

Montagne Farm

Location St. Albans, Vermont

Background

David Montagne grew up on his grandparents' farm and in 1975 David

began running the farm for his parents. As time went on, he and his wife

Cathy purchased the farm, and it grew from 80 cows to the nearly 700

they have now. The digester was installed and has been producing

electricity since September 18, 2007.

Cows 680 milking

Milk and Electricity

Production

The farm produces over 15 million pounds of milk per year and is

expected to produce 1.4 million KWHkilowatt hours (kh) of electricity

per year.

Estimated production of

manure solids

11,500 cubic yards annually


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Green Mountain Dairy

Location Sheldon, Vermont

Background

Owners Brian and Bill Rowell grew up on a farm in Albany, Vermont.

Brian's family owns Green Mountain Forest Products in Sheldon. Ten

years ago, Brian decided to go back into farming and started up Green

Mountain Dairy. Green Mountain Dairy Farm came online in March,

2007.

Cows 1,050 milking


Production

The farm produces over 20 million pounds of milk per year and is

estimated to produce 1,828,000 kWh of electricity per year.

Estimated production ofmanure solids


Blue Spruce Farm

Location Bridport, Vermont

Background

The Audets' Blue Spruce Farm was started in 1965 by Norm Audet, with

30 cows. Norm has passed on the farm to his three sons, Earnest, Earl

and Eugene and it has since grown to 1,500 cows.

Cows 950 milking


Production

The farm produces approximately 24 million pounds of milk a year and

produced 1.3 million kWh in the Cow Power program in 2006. The

Audets recently added a second generator to boost their energy

production.


manure solids



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St. Pierre Farm

Location Richford, Vermont

Background

The Pleasant Valley Farm, owned by Mark and Amanda St. Pierre, was

constructed in 1998. Mark began farming on his own in 1986, and at one

time operated four farms in the Richford area, until he consolidated and

built the Pleasant Valley Farm. Berkshire Cow Power, a subsidiary of

Pleasant Valley Farm, began generating electricity in 2006.

Cows 1,500 milking


Production

The farm produces over 40 million pounds of milk per year, and is

expected to produce 3.5 million kWh of electricity per year.


manure solids



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DIGESTED MANURE SOLIDS FUEL PROPERTIES

Digested manure solids (DMS) differ from typical

dairy manure in several main ways that dramatically

affect the materials suitability as a biomass fuel.

Typical dairy manure is 90 percent liquids and 10percent solids and has significant concentrations of

nutrients such as nitrogen, phosphorus and

potassium. DMS, on the other hand, has been

through the digestion process (thereby removing

some of the materials potential energy value), has

been dewatered using screw or belt press equipment

(effectively lowering the moisture content from 90

to 65 percent moisture, making is a stackable solid

versus a liquid slurry), and has significantly lower nutrient concentrations (the dewatering process

separates out water soluble nutrients from the solids).

In order to better understand the specific fuel qualities of DMS, samples from all four farms were

gathered and shipped to a nationally accredited biomass fuel testing laboratory in Golden,

Colorado. Proximate and ultimate analyses were conducted, both of which are common tests used

for determining the properties of solid fuels including biomass materials. Proximate analysis gives

the fixed carbon, volatile and ash content of biomass, helping to understand how a fuel will

combust. The ultimate analysis gives the elemental (C, H, O, S, N) composition.

DMS Ultimate & Proximate Analysis Results

Parameter Wet Basis Dry BasisMoisture Content 60.96 75.95% N/A

Ash Content 2.60 4.40% 9.05 11.85%

Volatile Matter 17.86 29.30% 69.22 73.85%

Fixed Carbon 3.59 7.02% 14.94 18.93%

Btu/lb (HHV1) 1909 - 3084 7809 - 7902

Carbon 11.29 - 18.72 46.69 - 47.96

Hydrogen 1.28 - 2.15 5.23 - 5.50

Nitrogen 0.56 - 0.73 1.41- 1.96

Sulfur 0.09 - 0.23 0.38 - 0.62

Oxygen 8.45 - 13.92 33.65 - 35.66

For comparison, proximate and ultimate analysis test results of typical woodchip boiler fuel are

included as well in the table below.

1 Higher Heating Value


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The material sampled has a sufficient energy value of 7,883 Btu/dry pound (only 5 percent less

than typical wood fuel). Although DMS has been de-watered, the moisture content is still quite

high as compared to other biomass fuels like green woodchips (60 to 75 percent compared to 35 to

45 percent, respectively). Ideally, solid fuels used for direct combustion would have a moisture

content less than 50 percent. DMS ash content (on a dry weight basis) ranged from 9 to nearly 12

percent. This is, on average, over 20 times more ash than from premium grade pellets and seven

times more than from typical woodchips (containing some bark). The volatile matter content of

DMS is fairly comparable to the volatile matter content of woodchips; similarly, the amount of fixed

carbon is comparable to that for wood. On a dry weight basis the Btu content is also very similar to

wood only 5 to 10 percent less.

Where DMS differs dramatically and where significant issues may arise with using DMS as a solid

fuel for combustion are the nitrogen and sulfur content. DMS material sampled from the four farms

contained, on average, over 27 times more nitrogen and more than 46 times more sulfur than

typical wood fuels. Both nitrogen and sulfur content in combustion fuels have a direct impact on

the amount of nitrogen oxide and sulfur oxide emissions, both of which have associated

environmental impacts. Both NOx and SOx are air pollutants that help form acid rain; NOx is also a

greenhousegas.

One critical parameter not analyzed by the laboratory was the bulk density of DMS material. Basedon the materials particle size, consistency, and moisture content we estimate DMS to weigh

approximately 37 lbs per cubic foot or roughly 1,000 lbs per cubic yard.

Typical Wood Fuel Ultimate & Proximate Analysis

Parameter Wet Basis Dry Basis

Moisture Content 35-45% N/A

Ash Content 0.25 1.0% 0.5 2.0%Volatile Matter 48 55% 80 90%

Fixed Carbon 7 10% 10 17%

Btu/lb (HHV1) 4,700 5,000 8,000 9,000

Carbon 29 30% 50 51%

Hydrogen 3 4 % 5 -7%

Nitrogen 0.03 - 0.04% 0.04 0.08%

Sulfur


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DMS AS A FUEL

Processing DMS into a Useable Fuel

DMS is not a viable fuel as is. The 10 percent ash content can present some challenges in

combustion, since most biomass combustion systems can handle fuels with ash content up to 6 or 7percent. Nutrient composition may also present some challenges, since this can translate to higher

ash content, formation of fused minerals, and pollutant emissions. But the main reason the material

is not suitable on an as is basis is the excessive moisture content. As was shown in the analysis

results presented above, DMS has a moisture content of 60 to 75 percent, while most solid biomass

fuel combustion systems require a drier fuel in the range of 50 percent moisture. When wet

materials are burned, water vapors are driven off and significant amounts of latent heat can be lost

with the combustion of wet materials. If materials can be dried, combustion can be made more

efficient. Solid biomass materials under 50 percent moisture content can generally be combusted

while materials over 50 percent moisture content typically prove difficult to burn.

There are still ways, however, to use DMS as a boiler fuel, all of which require some further

processing. One option would be to blend DMS with other drier biomass fibers, creating a lower

moisture fuel. It is also possible to avoid blending by further drying DMS, with two main options. .

The material can be dried:

1. to 5 percent moisture for densification (pelletization), or2. to approximately 45 percent moisture for loose combustion.

Pelletized solid fuels are easier to transport, store, convey and combust since they are uniform in

shape, size and moisture content. Pellets can also be a more marketable product and have a higher

energy density on a volume basis compared to loose, dried DMS. There is a significant energyinvestment in pelletizing fuels, however, and so for on-site use combusting loose, dried DMS

material can be more cost-effective. These two fuel options are the primary focus of the assessment

conducted here.

Drying DMS

There are numerous methods of drying materials such as cow manure beyond the levels achieved

with mechanical methods of dewatering, all of which involve using air to absorb moisture from the

material and to transport vapor. Methods of drying material vary depending on the starting

moisture content and the target moisture content, and so drying DMS for densification may use adifferent method than drying for direct combustion. Methods for both options are described in this

section.


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Rotary Drum Drying

For the DMS material from the Cow Power farms, the starting moisture

content is assumed to be, on average, 65 percent. For the first option (drying

to 5 percent moisture for DMS densification) more aggressive drying

methods are needed. The most common technique for drying green biomassmaterials for densification is the use of rotary drum driers, used for a wide

array of materials from sawdust at pellet plants to feed at grain mills.

A recent study by a

Polish researcher

concluded the energy requirements of

drying biomass materials for pelletization

are very significant1,508 Btu per one

pound of water evaporated2. The

following graph and tables illustrate theamount of energy required to dry DMS

to various moisture content levels using

the rotary drum method.

The table below shows the energy

required to dry DMS to various moisture

contents using the rotary drum method

as well as the net energy content after

drying. Based on our calculations this

would require nearly 2.0 million Btu perton of materialrequiring over 16 percent of the materials total energy value.

2 Swigon et al. 2005


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DMS will need to be dried for direct combustion as well, though not to the same degree as for

densification. Still, DMS will need to be dried from approximately 65 to approximately 45 percent

moisture content for direct combustion.

The following table illustrates the amount of energy required for both options assuming theadditional drying for loose combustion will require direct energy inputs. The starting moisture

content for both options is 65 percent and both options consider using a rotary drum drier.

Air Drying

However, loose DMS can be dried for direct combustion using other methods that are less energy

intensive than the rotary drum drier. These passive methods involve using air to drive the

evaporation process. Material can be dried passively as it is moved by conveyors, or the drying can

be done by blowing ducted air, which can be heated, over the material as it is conveyed thereby

speeding up the drying process. In both methods, the effectiveness of the drying depends largely on

the amount of material surface area exposed to dry air.

StartingMoisture

Content

Ending Moisture

Content

Energy Input

(Btu)

Resulting Energy

Value (Btu)

Percent

Energy

Required to

Achieve

LowerMoisture

Content

65% 45% 618,280 5,029,354 12%

65% 40% 769,080 5,675,760 14%

65% 35% 919,880 6,353,698 14%

65% 30% 1,070,680 7,063,168 15%

65% 25% 1,221,480 7,804,170 16%

65% 20% 1,372,280 8,576,704 16%

65% 15% 1,523,080 9,380,770 16%

65% 10% 1,673,880 10,216,368 16%

65% 5% 1,824,680 11,083,498 16%

65% 0% 1,975,480 11,824,500 17%

Drying to 45% Drying to 5%

Energy Required in Btu 618,280 Btus 1,824,680 Btus

Gallons of Oil/ton 4.50 13.25

Gallons of Propane/ton 6.75 20.0


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Natural Air Drying

Although piles of DMS located in the storage garages may experience some air drying, there are

ways to speed up the drying process. Stored piles of DMS can be spread thinly over the garage floor

with a bucket loader or skidsteer to expose more material to the air. Another method relies on

passive drying as the DMS material is conveyed from the screw/belt press units to the storage area.

If the material is spread thinly over the conveyor belt and the belt runs slowly, more moisture willbe evaporated. Agitating the material as it is moved can also speed up the process, but will add to

the electrical energy invested in drying.

Enhanced Air Drying

It may be feasible to reduce moisture in DMS by ducting warm air over a transport conveyor as the

solids travel from the screw/belt press units to the solids storage area instead of either passive air

drying or using a rotary drum drier. Instead of burning a fuel to provide the heat for the drying, it

would be possible to capture some warm air from the engine room or boiler room for this purpose.

If waste heat from either the engine or boiler room were used drying the DMS down to 45%

moisture content could be achieved without significant additional energy inputs.

DMS Densification

Densification Methods

After the material has been dried to a suitable moisture content, DMS may require further mixing

and grinding to get an even mixture of small particle size material that presses easily into the dies of

the machine making the pellets. If DMS is blended with other fibers such as grass or sawdust

mixing and regrinding will be even more important. According to the laboratory results from Mars

Minerals, the high concentration of relatively large fibers in DMS material (100 percent of DMSwere between 10 45 mesh), left over after the small fibers are removed in the dewatering process,

makes it necessary to further grind the material before it can be densified. The grinding can be done

with a hammer mill. However, there is both an art and science to densification and slight

adjustments to either the material or the settings of the pellet mill could yield a durable pellet

without further need for grinding and mixing.

Once the material has been dried and blended to

optimal conditions, this material is then fed into the

pelletizer. There are two main types of pellet mills: a

flat die mill and a ring die mill. A ram piston orpressing roller (depending on the type of mill used)

on the pelletizer forces the material through a die

which molds the material into the desired pellet shape and size. The material can be pressed into

the more typical pellet shape (between one or one and one-half inches long by approximately one-

quarter to five-sixteenths inches in diameter)or into larger briquettes, which may prove morefeasible given the materials characteristics.


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The high amounts of pressure and heat created in the process help the material to bind (heat is

generated by the piston or rollers). For wood pellets, lignin naturally present in the material holds

the pellets together and so no additional binders are required. For other materials low in lignin

content wax, vegetable oil, starch and clay can be added to the material to enhance the binding of

the material into a durable pellet.

Once the pellets are made, they are spread out to cool; once cooled, they are moved to storage

from where they would be distributed for use. The figure below summarizes this process.

There is significant energy input into conveying and drying the material for pelletization, but also

for pressing the material into pellets. This high-energy process can be costly.

Uses and Markets for Densified DMS

Ideally, the cost to produce these pellets would be off-set by the production of a marketable

product, either as an energy product or fertilizer/soil amendment. Off-site sale of this pelletized

material as an energy product is not feasible because of the high ash content produced during

combustion (as discussed in the preceding section on fuel properties). The high ash content from

these pellets is too high even for some industrial users. There is currently no local market for super

industrial grade pellets or briquettes for fuel.

Off-site sale of pellets as a fertilizer or soil amendment is technically feasible, though this material

would likely have a low market value due to reduced nutrient content after the dewatering process.

Soil amendments such as compost range in market value between $20 and $40 per cubic yard

(approximately $40 and $80 per ton). As a soil amendment, the added value of drying and

pelletizing the DMS is small when compared to the added costs.

While pelletization for off-site sales does not appear to be cost-efective, pelletization for use on-site

as an energy product could be technically feasible. However, economically speaking, there is also

little return on investment in making pellets for on-site use. The pelletizing equipment is expensive,

there is a significant amount of space required for pelletizing, and the energy input is high (and alsoexpensive). It would not make sense to invest the energy, space, time and money into making DMS

into pellets for use on-site when the material could be used for energy by directly combusting loose,

dried DMS or applying it as is for fertilization or soil amendment.

Blending& Mixin

Grinding Drying Densification& Extrusion

Cooling &Stora e


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Test Densification

As part of the assessment of the feasibility of using DMS as a densified boiler fuel, BERC collected

samples from all four farms and sent samples to Mars Minerals for preliminary evaluation of whether

the DMS can be effectively pelletized. Mars Minerals first conducted sieve analysis on the material

to determine the distribution of particle size. Mars Minerals found that 39.6% of the DMS wasretained by and 10 mesh screen and the remaining 60.4% were retained by a 45 mesh screen. This

means that there were no fine particles in the 80 to 325 mesh size. The likely reason for little fine

particles is that the belt or screw press dewatering process only captures the larger DMS fibers and

the fine particles remain suspended in the water. Having a range of particle and fiber sizes is helpful

for making quality pellets.

Mars minerals conducted several attempts to pelletize the

DMS samples with little success. Numerous runs using a

pin mixer pelletizer yielded partially agglomerated

granulesnot durable pellets. Mars Minerals concludedthat the material was too wet and contained insuffiencent

fine particles to effectively pelletize. They recommended

further testing of blending the DMS with other materials.

Further information on Mars Minerals pelletization trials

can be found in Appendix D.

In effort to get a second opinion, samples of DMS were taken to Palmer Garage located in North

Ferrisburg, Vermont. Nate Palmer, the owner of Palmers Garage, spread the DMS material on the

garage floor and air dried the material for two days and ran the dried DMS through a small 5

horsepower Chinese-made pelletizer. Mr. Palmer was successful at achieving the right conditions ofmoisture content, feed rate, and extrusion pressure to produce a durable pellet. See photo shown

above. While these pellets would likely not meet the Pellet Fuels Institute standards of pellet quality

(see Appendix C), it was demonstrated that the DMS material could be effectively pelletized

without further blending with other materials or the use of binders.


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COMBUSTION

Combustion Options

As with drying DMS, there are two options for combusting the material. One option is to combust

loose DMS that has been dried to 45 percent moisture content; the second option is to combustdensified DMS material that has been dried to 5 percent moisture and made into pellets. While

pelletization for off-site sale or on-site use as an energy product was not found to be the best use of

the material (see discussion in the above section on processing DMS into a useable fuel) it is

included in this discussion on combustion for the purpose of comparison.

Combustion Technologies

There are two main types of solid fuel combustion systems: stokers and suspension combustors.

Each type is described in more detail below. Both types could be suitable for combusting biomass

fuels, but each lends more easily to different applications.

Stoker Systems

Stoker systems feed fuel into the combustion chamber using augers (or stokers). Most often the fuel

is augered in horizontally on to a grate where the fuel is held during combustion. Many stoker

systems used fixed grates set at a downward angle and feed fuel in at the top of the grate and ash

tumbles to the bottom of the angled grate. Other stoker systems use a traveling grate that is slowly

moving material from the feed inlet to the ash outlet. Both fixed bed and traveling grate stoker

boilers are a readily-available commercial technology that has been the standard for combusting

biomass fuels. They are offered by a number of manufacturers in the United States. A travelinggrate stoker is the best system option for high ash fuels such as DMS because it does not allow the

minerals enough time to slag during combustion. A fixed grate option may be a viable option for a

small system using DMS fuel.

Pneumatic Fuel Injection Suspension Combustion

Several biomass combustion system manufacturers offer units that inject the biomass fuel into the

combustion chamber using forced air and burn the fuel in suspension. These systems are excellent

for large systems fueled with loose, dry materials with low ash content (such as sawdust). Due to

the extremely high ash content of the DMS material this system type is not recommended.

Mineral Fusion During Combustion

Total ash content is an extremely important factor in assessing a materials overall viability as a

biomass combustion fuel; however it is actually the mineral composition of the ash that is most

vital. The presence of certain forms of minerals in biomass fuel can cause serious complications

during combustion. Significant amounts of silica and alkali minerals such as potassium, sodium,


22/50


sulfur, or chlorine present in the ash can form slag or fused minerals that melt and bind to the

inside of the combustion chamber, blocking air flow and in turn limiting combustion efficiency. In

addition to impacting combustion efficiency, clinker creation can impact system performance by

jamming automatic ash removal equipment and even blocking the flow of new fuel stokered onto

the combustion bed grates. These minerals can also lead to fouling or the production of corrosive

exhaust gases that can degrade the interior of combustion systems.

To determine whether the DMS material would present issues with slagging and fouling as a result

of the mineral composition of the ash, laboratory analysis was performed (see Appendix C for full

results). As a general guideline, the alkali content of the ash should not exceed 0.4 lbs per million

Btu. Above this threshold the potential for mineral fusion increases significantly.3 The DMS

material has a calculated 2.39 lbs/MMBtu of alkali (nearly six times more the threshold level for

slagging issues). With this concentration of alkali minerals combusting the DMS (without blending

with other materials) would prove very problematic.

Combustion Emissions

Potential Emissions from DMS Combustion

The emissions from biomass-fired boilers are different from emissions of natural gas, propane or oil

boilers. A number of these components are air pollutants and are discussed below. Boiler emissions

are typically measured in pounds of pollutant per million British thermal units (Btu).

In terms of health impacts from biomass combustion, particulate matter (PM) is the air pollutant of

greatest concern. Particulates are pieces of solid matter or very fine droplets, ranging in size from

visible to invisible.

Relatively small PM, 10 micrometers or less in diameter, is called PM10. Small PM is of greater

concern for human health than larger PM, since small particles remain air-born for longer distances

and can be inhaled deep within the lungs. Particulate matter exacerbates asthma, lung diseases and

increases mortality among sensitive populations. Increasingly, concern about very fine particulates

(2.5 microns and smaller) is receiving more attention by health and environmental officials for the

same reasons. Investigation is ongoing into emissions of very fine particulates from biomass boilers.

The particulate emissions rate from DMS fuel is estimated to be roughly the same as for wood fuels,

approximately 0.1 0.2 lbs of PM 10 (without pollution controls) and depending on system size acombustor would require either a multi-cyclone mechanical device or a fabric filtration system such

as a bag house. BERC recommends a cyclone in sequence with a baghouse to minimize particulate

emissions to the greatest extent possible.

3 Miles, Tom.Alkali Deposits Found in Biomass Power Plants. April, 1995.


23/50


Emission rates of nitrogen oxides from DMS fuel would be higher than that for typical wood fuel,

about 27 times greater or nearly 4.5 lbs per million Btu. Similarly, emission rates of sulfur oxides

from DMS fuel would be about 46 times the amount of that from typical wood fuels; however, this

rate would be less than that for heating oil, and so would not likely trigger air quality permitting

thresholds. Both the system size and its potential to emit pollutants can trigger air quality

thresholds. If a system has the potential to produce more than 10 tons of NOx per year, airdispersion modeling would be required; at more than 50 tons per year, the system (or farm) would

be considered a major source of pollution, triggering an air quality review and possibly requiring

installation of emissions reduction equipment. In short, the greater the number and overall quantity

of pollutants emitted, the more regulations will be triggered at the State level and possibly up to the

Federal level.

Emissions Rates from Wood Combustion

The chart below characterizes emission rates of several criteria pollutants from wood, oil, natural gas

and propane, for comparison to those from DMS fuel discussed above.

This table is from the Resource Systems Group report titled Air Pollution Control Technologies for Small Wood-fired

Boilers (2001).


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FEASIBILITY OF ELECTRICAL GENERATION FROM DMS COMBUSTION SYSTEM

Electrical Generation Technology

While thermal loads can readily be met with smaller combustion systems and densified DMS

(pellets), electrical generation requires larger boilers generating sufficient amounts of steam byburning sufficient amounts of fuel. In this case, loose, dried DMS fuel is best. It is assumed that

systems below 100 kW would use steam engines and systems larger than 100 kW would utilize

steam turbines.

Potential for Electrical Generation

The following table provides ballpark calculations of potential electrical generating capacity based

on the volumes of DMS generated at each farm. These numbers are not detailed engineering

calculations.

Farm

Annual DMS

Generation

(green tons)4

Hourly DMS

output5

(green tons)

Boiler size

(MMBtu/hr

output)6

Steam

output

(lbs/hr)7

Potential

Electrical

Generation

(kW/hr)8

Montagne

Farm 5,750 0.82 2.6 2,224 55

Green

Mountain

Dairy 8,750 1.25 4.0 3,385 85

Blue SpruceFarm 8,000 1.14 3.7 3,095 77

St. Pierre

Farm 12,500 1.78 5.8 4,803 121

As is shown in the chart above, most of the farms do not produce enough DMS to fuel the larger

steam boilers required for electrical production. The greatest potential for electrical generation is at

the St. Pierre Farm, where an additional 121 kW of electricity could be produced if all DMS

material generated on the farm was dried to 45 percent moisture and used as fuel. This is, however,

on the small side for warranting an electrical generation project. Ultimately, it is up to CVPS todetermine where electrical generation could make the most sense, given their program goals. It is

4 Assumes 1,000 pounds per cubic yard for 65% moisture content DMS and that100% of the farms DMS generation isdevoted to fuel versus bedding or compost.5 Assumes 20 hours per day and 350 days per year6 Assumes a high pressure (300PSI) steam boiler system7 Assumes 65% boiler efficiency8 Assumes 100% of high pressure steam is used for electrical generation (no thermal)


25/50


important to note that the electrical generation capacity could be increased by supplementing with

wood fuels.


26/50


CASE STUDIES OF EXAMPLE PROJECTS

Several examples of existing manure-pelletization projects were found through BERCs literature

and on-line review. While there were no operational projects actually pelletizing and combusting

dairy manure, there were several projects worth mentioning where manure is pelletized for energy

and fertilizer and manure is directly combusted.

Manure Pelletization for Fertilizer

It should be noted that many of the pelletization projects mentioned in this section differ slightly

from the common pellet referred to by those in the energy industry. These pellets are perhaps

more accurately called granules.

Promest BV: Helmond, Netherland

This centralized bio-gas facility aimed to take 100,000 tons of swine manure for digestion and make10,000 tons of manure pellets for export to Spain and Portugal for agricultural markets. The plant,

originally built in 1990 is no-longer operational due to technical issues related to manures

corrosive properties and the high cost of transporting the raw manure to the centralized plant.9

Perdue-AgriRecycle: Seaford, Delaware

This poultry manure pelletization plant, designed as a waste management strategy for local chicken

farmers, has processed approximately 60,000 tons of chicken manure since it opened in July,

2001. After incineration and composting proved to be poor choices for dealing with the excessmanure (due to emissions restrictions and logistical problems, respectively), pelletizing the material

for fertilizer became the most feasible option since the waste could be easily transported before and

after processing and because the plant produced a marketable product.

A $13 million investment from Perdue and a grant from the State of Delaware helped build the

plant that now processes 95,000 tons of manure per year. Before the pelletization plant, farms were

spreading some of the material on their fields according to their Nutrient Management Plans. Now

manure is swapped between chicken farmers and grain growers, becoming a pelletized fertilizer

before being applied at grain farms.

The plant now serves a mutually-beneficial relationship, where Perdue contracts the clean-out and

transport of the waste to a third party at no cost to the growers, and the plant is supplied with lots

of material for fertilizer (one chicken house generally supplies 200 tons of manure per year). Once

the delivery truck arrives at the plant (one of about 10 that visit per day), it is driven directly into a

large, completely enclosed holding area where the manure is unloaded after the doors are closed.

9 http://igitur-archive.library.uu.nl/dissertations/2007-0219-200257/c5.pdf


27/50


The negative air pressure of the plant draws air in from the outside, preventing the escape of any

dust or particulates, and the air inside is completely changed and cleaned with special scrubbing

technology 9 to 10 times every hour.

The manure is smashed by machine and is then moved to a 10 by 40 foot heating chamber where

the material is dried and pasteurized by spinning it through a stream of heat (650 F). The productcan be as hot as 180 F, killing any remaining bacteria and fungus; it is then ground and mixed

with steam so that it can be shaped into pellets. These pellets are packaged in one-ton containers

that are then shipped by truck or railway car and are primarily for large-scale agricultural

applications such as amendment for golf courses, catfish feed, or fruit and vegetable fertilizer. An

additional grinder has been installed to make smaller pellets which are more suitable for commercial

markets such as lawn care and gardening.

Manure Briquetting

Pelletization is just one method of densifying material for use as a fuel. Loose materials includingcow manure can also be pressed into larger bricks or briquettes. While no specific cases of industrial

briquetting of cow manure were found, multiple references to programs promoting briquetting of

cow manure as cooking fuel in developing counties were found.

Cow Manure for Combustion

Weise Farms: Greenleaf, Wisconsin

This 1,600-cow farm near Wrightstown, Wisconsin incinerates most of the farms manure using a

system that will generate steam to power a turbine/generator combination with the capacity toproduce 600 kilowatts (kW) of electricity, or enough to power 700 homes. Wiese Farms has signed

a contract to sell the electricity to Wisconsin Public Service (WPS). While numerous projects

combust poultry manure, this farms system is one of few examples of using straight cow manure as

a combustible fuel.

Previously, manure had been applied to land used to grow 800 to 1,000 acres of winter wheat.

Excess manure had to be trucked off site, as far as ten miles, which was getting expensive. The

intent of this project was turning a waste into power as a cost-effective way to remove excess

manure.

Skill Associates, based in Kaukauna, Wisconsin, designed the system. Manure at the Weise Farm is

deposited into reception pits located under each barn, then into a dry pit, and then further to a

homogenizing tank that is 35 square feet and 10 feet deep and holds about 2 days worth of

manure. Agitators in the tank keep the manure moving to reduce anaerobic activity and odor and

also to chop the manure into finer particles. Waste grain and feed, dry-pack manure and milking

water are sometimes added to the tank as well.


28/50


The finely chopped manure is then pumped from the homogenizing tank to a bio dryer, which is a

concrete tank resembling a bunker silo. Augers mix this material with water and heated air (160 to

200 F) is pumped through a ground layer of gravel. This drying and mixing process brings drier

solids to the top as the wetter solids sink towards the bottom gravel layer and heat source.

Computers regulate the whole process and sensors track the temperature and moisture content of

the mixture; the augers can be directed to work in specific areas of the dryer. Moisture leaving themixture is exhausted through fans at the top of the building. Dry manure can be diverted at this

point for use as bedding; otherwise, the material is sent to the boiler house located 23 feet away.

Within the boiler house, the conveyor dumps dry manure into a steel feed tank that is

approximately 20 by 40 feet and 10 feet deep, holding 3 days worth of boiler fuel. From here,

the material is augered and conveyed to a feed box, from which it is fed into the firebox of the

incinerator. Woodchips are burned at first to get the

system up to temperature; the manure is burned at

1,800 to 2,000 F and blowers force air into the

combustion chamber for more complete combustion.The ash produced reportedly amounts to a manure

spreaders-worth every week.

Steam is produced at 305 pounds per square inch (psi)

to turn a turbine that in turn drives an electrical generator. Waste heat from electrical generation is

collected and piped back into the drying system. The system is requires 6 to 15 gallons of well

water per day to supplement the recycled water from the cooling tower.

Based on telephone conversations with several industry experts who were involved with the

installation of the system and postinstallation trouble-shooting, this

system has been plagued with a

range of on-going issues. Many of

the issues facing the system stem

from the nutrients and minerals

concentrated in the dehydrated

manure boiler fuel.

Eagle Creek Wholesale: Portage County, Ohio

Eagle Creek Wholesale LLC, a greenhouse operation Portage County heats 3.5 acres of greenhouse

space with cow and horse manure, sawdust and woodchips and there are plans to add 2 acres more

acres of greenhouse space to be heated the same way. The greenhouse is one part of a

mulitcompany family business that includes cattle farming and a mulch and sawdust service. The

other businesses fuel the greenhouse operation: the cattle produce fuel and the sawdust is delivered

to horse farms where more fuel is collected.


29/50


The goal is to be completely energy self-sufficient. John Bonner, general manager of Eagle Creek,

found biomass to be a financially feasible source of renewable energy (in addition to wind: the

operation also has a 50 kW wind turbine with a second one on the way). Hes not sure what the

payback from the biomass boiler will be, but is impressed with the tremendous fuel cost savings

over a natural gas bill that was approaching $200,000 in the 2005-06 heating season.

Eagle Creek's 5 million-BTU boiler is fired by a mixture of sawdust, woodchips, and cow and horse

manure.

These solid fuels are dried and stored in a room adjacent to the boiler in two piles contained in

concrete stalls: one pile of a manure mixture and one pile of a wood mixture. Paddles on the floor

of each stall move, sift and mix the fuels before sending them to the boiler. The boiler keeps more

than 60,000 gallons of water at 200 degrees and pressurized to 25 pounds per square inch; this

superheated water is piped to the greenhouses for heating.

Others

As part of the literature review conducted for this study numerous other preliminary projects

looking to use manure as a fuel were identified. Many of the other projects identified had

announced their intent to use cow manure as a boiler fuel or were still in the preliminary stages of

project development. Several combustion system vendors approached claimed numerous installed

systems using cattle manure as boiler fuel. When pushed further for project specifics, claims were

altered to suggest these projects were still under consideration by clients. Several examples of energy

projects or studies using cow manure as boiler fuel are listed below:

A corn ethanol plant in Herford, Texas owned by Panda Energy is planning to use cowmanure as boiler fuel to meet the plants steam needs. Texas A&M University is currently conducting and study on manure from cattle feedlots as

a boiler fuel

A nonprofit organization based in Colorado, ICAST, is conducting a study of feedlot cattlemanure as a boiler fuel.


30/50


CONCLUSIONS

The DMS material sampled had a sufficient energy value of 7,883 Btu per dry pound (only 5

percent less than typical wood fuel). Two main factors make DMS more favorable for use as a

biomass combustion fuel than normal cow manureit has been de-watered and many of the

problematic nutrients have been removed with the water. While DMS is comparatively better suitedfor both densification and combustion than raw manure, it still faces numerous challenges.

DMS was not found to be a viable fuel as is, due mainly to its high moisture content. The material

would need to be dried in order to use it as a boiler fuel. It would be possible to dry the material

from 65 to 5 percent moisture content and pelletize it for easier storage, conveyance and

combustion or application (depending on whether an energy or soil amendment product is being

produced). This process would involve using a small rotary drum for drying, a hammer mill for

grinding the material down to a small particle size, and a pelletizer (or pellet mill) to make the

pellets. These pellets could then potentially be sold as an energy or soil amendment product;

however, with ash content over 10 percent and a diminished nutrient content after the dewateringprocess, neither potential product is likely to be viable in the respective markets. The pellets could

instead be used on-site for energy production; however, pellets are energy- and cost-intensive to

produce, with as much as 16 percent of the energy present in the material being used for drying to

5 percent. The farms would be better off directly combusting loose DMS material dried to 45

percent moisture using forced warm air while the material is spread thin over a conveyor belt.

Many equipment manufacturers claim they are able to effectively burn cow manure as a boiler fuel.

However, there are practically no installed systems in the United States at this time. Perhaps the

only known system in the US that has attempted to burn dried cow manure on a large-scale is the

Weise Brothers Farm that installed a manure drying system, a 400 horse power high pressure steamboiler, and 600 kW steam turbine at their farm in Greenleaf, Wisconsin. The 1,600-cow farm

incinerates most of its manure to produce enough electricity to power 700 homes. Unfortunately,

since the system was first installed and throughout its operation, it has been plagued by numerous

issues most of which stem from using cow manure as a boiler fuel. Eagle Creek Wholesale in

Portage County, Ohio heats 3.5 acres of greenhouse space with manure, but supplements with

sawdust and woodchips.

DMS produced by the Cow Power Farms has been dewatered and is absent many of the nutrients

and minerals causing slagging and fouling problems seen at Weise Farms. Despite leaching out

many of the problematic nutrients in the dewatering process, there was still nearly six times morealkali minerals than the recommended threshold of 0.4 lbs/MMBtu. At this concentration

significant slagging and fouling of minerals would occur during combustion, making the use of

DMS as a reliable boiler fuel extremely unlikely.

Given the small volumes of DMS produced beyond the farms bedding requirements, most farms

had insufficient amounts of possible boiler fuel to fire a large enough steam boiler to warrant

electrical generation using steam turbine technology. Electrical production could be possible at


31/50


farms producing substantial DMS fuel, with the largest potential capacity at the St. Pierre farm.

CVPS should decide where electrical generation makes sense, given the results shown here and their

program goals. Electrical generation capacity could be increased by supplementing with wood fuels.

While there are insufficient volumes of fuel to power a large enough steam boiler to produce

electricity, there is enough fuel to run a smaller boiler that could help meet the farms thermal load.

Pollutant emissions could be an important factor in the feasibility of DMS as boiler fuel. While

particulate emissions, which are roughly equivalent to those from wood, could be minimized with a

cyclone and baghouse in sequence, NOx and SOx emissions will be much greater than those from

wood. SOx emissions will not likely be of concern to air quality regulators since the emission rate

from DMS would still be less than from heating oil. NOx emissions, however, could be a greater

concern as they could be as much as 27 times greater than those from wood. Any farm interested in

pursuing the use of DMS as boiler fuel should involve air quality regulators early on in the

development of the project concept. CVPS may look to other states, such as Wisconsin, that may

already have systems in place for addressing air quality issues. These states could serve as examplesfor the air quality side of a program focused on converting farms to using DMS as boiler fuel.


32/50

I HazenResearcn.nc.I'|AZEN c"io"", oio+o-isrI E;l333l3l3,iiilBiomass nergyResource enterAdanSherman43 State StreetMontpeler , W 05602Reporti gBasisProximateZ)

Moi tureAshVolat i I eFixedCTotalSul urBtu/lb (HHV)]'1l'lF tu/l bl"lAF tu/lbAir Dry Loss 3)

Ultimate 3)l'|o stureCarbonHydrogenNi rogenSul urAshOxygen*TotalChl ri ne*

As Rec'd

Date December3 2008HRIProject 002-ZM5HRISeriesNo. 1117/08-LDateRec'd. L2/09/08Cust .P.0.#Sampledentif icationGreenMountain airy11/201-0:30 t'|

Air Dry

60. 63.5329.306.2r100. 00.1613084320L

60.33

60.96t8.722.L50.560.163.53t3.92100.0

0.009.0575.0515.90100.000 413790287578689

0.0047 965.50L.420.419.0535.66100.00

l - . bu8.9173.8515.64100.000 4067775

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Formsf Sulfur(asS,Z)Sul atePyri i c0rgancTotal

Waten olubleAlkalies (fr)0 41

Lb. Alkali/MM tu=Lb. Ash/MMtu= LL.46Lb. S02/MMtu= 1.04HGI= @ X MoistureAs"Rec'd. p.Gr.=FreeSwelling ndex=F-Factor(dry),DSCF/] '1MTU=9,79RgportPrepared y:t.Vidria Sir,-)ar krffiFuelsLaboratory upervisor

0.16

Na20Yr20* 0xygen y Difference.* Not usually reported s part of the ultimateanalysis.

An Employee-Ownedompany


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II.U\ZENIHazenResearch,nc.4601 ndiana treetGolden, O 80403 USATel: (303)279-4501Fax: 303) 78"1528

Biomass nergyResource enterAdam hennan43 State StreetMontpelier,W 05602

DateHRIProjectHRISeries No.DateRec'd.Cust .P.0.#Sampledentif icationST. P'iemeFarmL1./20 :45 PM

Air Dry

Decenber3 2008002z]..|sLLLT08-2L2/09/08

Reporti gBasisProximate3)

Moi tureAshVol ti I eFixedCTotalSul urBtu/lb (HHV)MMFtu/lbMF Btu/lbAir DryLoss Z)

Ultinate fr)Moi tureCarbonHydrogenNi rogenSulurAsh0xygen*TotalChl rine**

As Rec'd

0.09

0.00L0.7974.27L4.94100. 00 384793989868899

1.6710.6173. 314.69100. 00.3787806

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75.952.60t7.863.59100.00.09219091961

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0.0046.93s.331 410.38L0.7935.16100.00

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Formsf Sulfur asS,fr)Sul atePyri i corganiTotal

Water oluble lkalies E)Na20K20

* 0xygen y Difference.* Not usuallyreported s part of the ultimateanalysis.

Lb. Alkali/ l ' lM tu=Lb. Ash/]'|t'l tu= 13.59Lb. S02/M}'ltu= 0.97HGI= @ Y,MoistureAs,Rec'd. p.Gr.=FreeSwelling ndex=F-Factor(dry),DSCF/l'l]'iTU=9,50ReportFrepared y:,Vi.uja 6r+r+.rGbr@Fuel Laboratoryupervior

0.38



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II.AZENIHazenResearch,nc.4601 ndiana treetGolden, O 80403USATel: (303)279-4501Fax: 303) 78-1528

Biomassnergy esourceenterAdamhennan43 State StreetMontpelier.W 05602

Date Decenber 3HRIProject 002-ZM5HRISeriesNo.1117/08-3DateRec'd. L2/09/08Cust .P.0.#Sampledentif icationMontagnearmLL/20L2:00PM

Air Dry

2008

Reporti gBasisProxinateX)

MostureAshVol t'i eFixedCTotalSulurBtu/lb (HHV)l'lt'lF tu/lbMF Btu/lbAir DryLoss X)

Ult inate 8)l4oi tureCarbonHydrogenNitrogenSulurAsh0xygen*TotalChl nine**

Forns f Sulfun asSufatePyri i c0rganiTotal

As Rec'd

0.23

0.0011 8569.2218.93100. 00.62078098955B8s9

2.L311 6067.75L8.52100.00.6077643

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62.884.4025.707.02100. 00.23028993035

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0.0046.695.231.960.6211.8533.65100. 0

2.L345.705.L2r .920.6111.6032.92100.00

Lb. Alkali/t'|]'lBtu=S,U) Lb. Ash/l4l.|tu=Lb. S02/MM tu=HGI= @AsRec'd.SP.Gr.=FreeSwelling ndex=F-Factor(dry),DSCF/M]'|TU=ReportP.repared y:t ..Vttr"lc-.Arst*'-- Av--ffiFuelsLaboratory upervisoranaysis

15. 81.59I }'loisture9.680.62

WaterSolubleAlkalies (X)Na20K20

* Oxygen y Difference.* Not usually reportedas part of the uitimateAn Employee-Ownedompany


35/50

IF]AZENIHazenResearch,nc.4601 ndiana treetGolden, O80403USATel: (303) 79-4501Fax: 303) 78-1528

Bionass nergy esearchenterAdanShermanP0Box1611-Montpeuer,W 05602

Elementalnalvsis f Ash E)

HRIProject 002'ZV0HRISeriesNo.A1.66/09DateRec'd. 0I/26/09Cust.P.0.#Sampledentification:BlubSpruce armSolids1/16934AH

AshFusion enperaturesDeq )

February 5 2009

ReducingAtmosphere21002LL52L252140

In i t i a lSofteningHemipheri a1Fluid

Date

OxidizingAtnosphere2L392L492L502l5r

sI02AL2O3TI02FE2O3cAo].,tG0NMOK20P205s03L Lc02Total

28.2L0.630.041.1323.706.817.L210. 010.303.003.700.8295.96

Note: The ashwascalcined @1LL0deg FFugls

(600C) prior te;analysis.' l : - " . . - .

ReportPrepared y:

. uunnngnamLaboratory up



36/50

IFIAZENIBiomass nergyesearch enterAdamShermanPOBox1611Montpeuer,T 05602

HazenResearch,nc.4601 ndiana treetGolden, O 80403 USATel: (303) 79-4501Fax: 303) 78-1528 DATE February5, 2009PROJ.# 002-Z'lOoTRL# 4166/09REC'D 01n6l09

ldentification Moisture, /o

A166/09-1 BlueSDruce armSolids /16 344M

Note: TU/lbalues renotsulfur orrected.

69.22

GeraldH.Cunningham



37/50

HazenResearch,nc.4601 ndiana treetGolden, O 80403 USATel: (303) 79-4501Fax: 303) 78-1528 DATE February 5,2009PROJ. O02-7t0CTRL# A166/09REC',D 01t26109iomassEnergy esearch enterAdamShermanPOBox161Montoeuer.T 05602

Number ldentification Sodium s Na2O,% Sodium s Na2O,%

A166/09-1 BlueSDruce armSolids /16 34AM 0.170 0.551

II.1AZENI

Gerard .Cunningham



38/50

IF1AZENIHazenResearch.nc,4601 ndiana treetGolden, O 80403 USATel: (303) 79-4501Fax: 303) 78-1528 DATE February5, 2009PROJ.# OO2-a'/0CTRL# A166/09REC'D 01'26109iomass nergyesearch enter

AdamShermanPOBox16t1Montpeuer, T 05602

ldentification Potassiums K2O,% Potassium s K2O,%

A166/09-1 BlueSprucFarmSolids /16 344M 0.296u.voz

GerafdH. Cunningham

An Employee-Owned ompany


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PFI Standard Specification for Residential/Commercial Densified Fuel18-June-2008

Page 1 of 8

Copyright June 18, 2008

Pellet Fuel Institute (PFI) Standard Specification for Residential/Commercial Densified Fuel

1. Scope1.1 This specification is applicable for the determination of fuel quality grade for Residential

or Commercial Densified Fuel as shown in Table 1.1.2 Fuel properties included in the specification are fines, bulk density, diameter, length,

chloride, ash fusion properties, moisture content, heating value, pellet durability index

and inorganic ash content. Bag weight is measured but is not part of the determination offuel quality grade.

1.3 This specification is for the use of purchasers and users of Residential/CommercialDensified Fuel in selection of the grade most suitable to their needs.

1.4 Commercial users include commercial facilities that utilize densified fuel burningappliances or equipment that have the same fuel requirements as residential appliances.

Commercial applications should not be confused with industrial applications, which canutilize a much wider array of materials and have vastly different fuel requirements.

1.5 The values stated in inch-pound units are to be regarded as the standard. Any valuesgiven in parentheses are mathematical conversions to the International System of Units(SI units), which are provided for information only and are not considered standard.

1.6 This standard specification does not purport to address all of the safety concerns, if any,associated with its use. It is the responsibility of the user of this standard specification to

establish appropriate safety and health practices and to determine the applicability ofregulatory limitations prior to use.

2. Referenced Documents2.1 ASTM Standards:ASTM E 873-82 (2006) Standard Test Method for Bulk Density of Densified Particulate

Biomass Fuels.ASTM E 871-82 (2006) Standard Test Method for Moisture Analysis of Particulate Wood

Fuels

D 1102-84 (2001) Standard Test Method for Ash in Wood

ASTM E 791-90 (2004) Standard Test Method for Calculating Refuse-Derived Fuel Analysis

Data from As-Determined to Different Bases

ASTM E 776-87 (2004) Standard Test Method for Forms of Chlorine in Refuse-Derived FuelASTM D 4208-02e1 Standard Test Method for Total Chlorine in Coal by the Oxygen Bomb

Combustion/Ion Selective Electrode Method

ASTM D 6721-01 (2006) Standard Test Method for Determination of Chlorine in Coal by

Oxidative Hydrolysis Microcoulometry

ASTM E 711-87 (2004) Standard Test Method for Gross Calorific Value of Refuse-DerivedFuel by the Bomb CalorimeterASTM E29-06b Standard Practice for Using Significant Digits in Test Data to Determine

Conformance with SpecificationsASTM C702-98(2003) StandardPractice for Reducing Samples of Aggregate to Testing Size

ASTM D1857-04 Standard Test Method for Fusibility of Coal and Coke Ash


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2.2 Other Referenced Documents:Kansas State University -Mechanical Durability of Feed Pellets, Call Number: LD2668 .T4

1962 Y68

PFI Quality Assurance/Quality Control (QA/QC) Program for Residential/Commercial

Densified Fuels

3. Terminology3.1 Definitions: General3.1.1 Bulk Density the fuel mass per cubic foot of the fuel sample as determined by

ASTM E873-82 (2006).

3.1.2 Bag Weight the weight of the fuel plus the bag, determined by weighing a standardbag of fuel.

3.1.3 Diameter the average diameter of the fuel pellets in the fuel sample.3.1.4 Pellet Durability Index (PDI) a parameter for specifying the ability of the fuel

pellets to resist degradation caused by shipping and handling.

3.1.5 Fines the percentage of fuel material in the fuel sample passing through a 1/8 inchscreen when the fuel is sampled after completion of production and bagging andbefore transportation, unloading, distribution, use, etc.

3.1.6 Inorganic Ash the percent inorganic material in the fuel sample as determined byASTM D1102-84 (2001).

3.1.7 Length the weight percent of pellets exceeding 1.5 inches in length in the fuelsample.

3.1.8 Moisture the moisture content of the as-received fuel sample as determined byASTM E871-82 (2006).

3.1.9 Heating Value The higher heating value of the fuel sample as determined by ASTME711-87 (2004).

3.1.10 Additives Any substance other than virgin cellulosic material that has beenintentionally introduced into the fuel feed stock prior to pellet extrusion (exceptsteam/water). Trace amounts of grease or other lubricants that are introduced into thefuel processing stream as part of normal mill operations are not considered as

additives.

3.1.11 Chemically Treated Materials Any feed stock material (cellulosic or otherwise) thathas at any time been processed, formed, treated or contaminated with any bondingagent, resin, preservative, surface coating or other finish, or any other chemical

compound. Trace amounts of grease or other lubricants that are introduced into the

fuel processing stream as part of the normal mill operations are not considered aschemically treated materials.

3.1.12NIST - The National Institute of Standards and Technology is a federal technologyagency that develops and promotes measurement, standards, and technology.


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TABLE 1 PFI Fuel Grade Requirements

Table 1 Notes:

1. There is no required value or range for Heating Value. It is required to print the mean higherheating value in BTU per pound as well as the ash content on the fuel bag label using a bar scale

to represent the mean value 2 Std. Dev. See note 9.

2. The bag must be labeled indicating which PFI grade of material is in the bag. See note 9.3. The bag label must also disclose the type of materials as well as all additives used. For

purposes of this standard specification, additives are defined in 3.1.10. See note 9.

4. It is required that manufacturers include on their bags the PFI logo and in a printed block the

guaranteed analysis of the fuel. See note 9.5. PFI prohibits the use of any chemically treated materials. For purposes of this standard

specification, chemically treated materials are defined in 3.1.11.

6. The following applies to all limits in this table: For purposes of determining the fuel grade,all properties must fall at or within the specified limits listed for a particular grade. Observed or

calculated values obtained from analysis shall be rounded to the nearest unit in the last right-

hand place of the figures used in expressing the limit in accordance with ASTM E 29-06b

Standard Practice for Using Significant Digits in Test Data to Determine Conformance with

Specifications.

7. It is the intent of these fuel grade requirements that failure to meet any fuel property

requirement of a given grade does not automatically place a fuel in the next lower grade unless itmeets all requirements of the lower grade.


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8. It is required to report ash fusion properties at a frequency as specified in the PFI QualityAssurance/Quality Control (QA/QC) Program for Residential/Commercial Densified Fuels.

9. Refer to PFI Quality Assurance/Quality Control (QA/QC) Program for

Residential/Commercial Densified Fuels for specific labeling requirements for fuel properties

and other information.

4. Detailed Requirements4.1 The various grades of densified fuel shall conform to the limiting requirements shown in

Table 1.

5. Sampling and Sample Handling5.1 The reader is strongly advised to review all intended test methods and sampling

requirements prior to sampling in order to understand the importance and effects ofsampling technique and special handling required for each method. Representative

samples shall be taken for testing in accordance with the PFI Quality Assurance/QualityControl (QA/QC) Program for Residential/Commercial Densified Fuels.

6. Test Methods6.1 The requirements enumerated in this specification shall be determined in accordance

with the referenced ASTM test methods or other referenced methods except wheremodifications are noted or in accordance with the test procedures specified.

6.1.1 Bulk Density Test Method E 873-82 (2006) except this method shall be revised toutilize a 1/4 cubic foot container that is tapped 25 times from 1 inch. In order toinsure that an adequate sample quantity is available for this revised method, a

minimum sample size of 12 pounds (5.44 kilograms) is recommended.

6.1.2 Bag Weight Record and report the sample bag weight using the balance or scalespecified in 8.1. All weights shall be measured and recorded to the nearest gram.6.1.3 Diameter - Select 5 pellets randomly out of the pellet sample being evaluated and

measure the diameter of each pellet with the caliper specified in 8.2. Each measured

pellet diameter shall be recorded to the nearest 0.001 inch. The average pellet

diameter as well as the range of all pellet diameters measured shall be calculated and

reported to the nearest 0.001 inch .6.1.4 Pellet Durability Index (PDI) - Durability shall be determined by using the Kansas

State method with one modification. The screen size used in determining durability

shall be a 1/8-inch (3.17 mm) wire screen sieve. A summarization of the KansasState method with the specified modification is provided in Annex A.1. All weight

measurements shall be conducted using the analytical balance specified in 8.3 andrecorded to the nearest 0.1 grams. It should be noted that the pellets remaining afterperforming the fines determination as specified in 6.1.5 can be used without further

preparation to conduct the durability test.

6.1.5 Fines Determined using the following procedure that incorporates the use of a 1/8-inch (3.17 mm) wire screen sieve. All weight measurements shall be recorded to thenearest 0.1 gram.

6.1.5.1 Secure a representative fuel sample.


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6.1.5.2 Reduce the sample size down to a minimum of 2.5 pounds (1,133 grams) using asample splitter with 3.5-inch (89 mm) slots. Larger sample sizes may be used.

6.1.5.3 Using the analytical balance specified in 8.3, weigh the sample and record as theinitial sample weight.

6.1.5.4 Weigh the receiving pan and record the weight.6.1.5.5 Attach a 1/8-inch (3.17 mm) screen to the receiving pan and place the pelletsample on the screen using care not to overload the screen. The maximum load

on the screen should not exceed 1 pound (453 grams) of pellets per 100 squareinches (654 square centimeters) of screen surface area. Smaller screens may

require the sample to be screened in increments.

6.1.5.6 Screen the sample by tilting the screen side to side 10 times.6.1.5.7 If the sample is being screened in increments, after the first portion has been

screened remove the 1/8-inch (3.17 mm) screen from the base pan, and empty the

pellets off the screen.6.1.5.8 Repeat 6.5.1.5 through 6.1.5.7 until the entire sample has been screened.6.1.5.9 Remove the 1/8-inch (3.17 mm) screen and weigh and record the weight of thebase pan with the fines.6.1.5.10 Calculate and report the percent of fines to the nearest 0.01% as follows:

% Fines = [(Weight of Base Pan + Fines) (Weight of Base Pan)] x 100

Initial Sample Weight

6.1.6 Inorganic Ash - ASTM D 1102-84 (2001)6.1.7 Length - Starting with 2.5 pounds (1.13 kilograms) of pellets randomly selected from

the sample being evaluated, hand sort to identify pellets over 1.50 inches in length.

Use the caliper specified in 8.2 or a certified measuring block as specified in 8.4 to

confirm that a pellet exceeds the specified length. The weight percent of all pelletsexceeding the specified length shall be reported. In addition, of the pellets exceeding

the specified length, the longest pellet shall be identified, measured with the caliperspecified in 8.2, and the length reported as the maximum pellet length.

6.1.8 Moisture - ASTM E 871-82 (2006)6.1.9 Higher Heating Value - ASTM E 711-87 (2004)6.1.10 Chloride - ASTM E 776-87 (2004) or ASTM D 4208-02e1 or ASTM D 6721-01

(2006)

6.1.11 Ash Fusion - ASTM D1857-047. Sample Preparation

7.1 A sample preparation schematic is shown in Annex B.1 to illustrate how a 40 lb bag ofpelletized material should be subdivided to perform the analysis procedures. All samplesubdividing shall be conducted utilizing a sample splitter with a slot width of 3.5 inches

(89 mm) and meeting the requirements specified in ASTM C702-98 (2003).

8. Equipment and Supplies8.1 Scale A scale capable of weighing the sample bag of fuel to within 0.1 lb (0.05 kg).

Must meet the calibration requirements specified in 9.1.


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8.2 Caliper A vernier caliper capable of measuring fuel diameter and length to within0.001 in. (0.025 mm). Must meet the calibration requirements specified in 9.2.

8.3 Analytical Balance A balance with a resolution of 0.1 g or better. Must meet thecalibration requirements specified in 9.3.

8.4 Measuring Block A 1.50 inch long gauge block used for screening fuel pieces forlength. Must meet the requirements specified in 9.4.9. Calibration and Standardization

9.1Scale - Perform a multi-point calibration (at least five points spanning the operationalrange) of the scale before its initial use. The scale manufacturer's calibration results are

sufficient for this purpose. Before each certification test, audit