Black Pellets: A Fuel for Power

Choosing Pellet Fuel to Cut Costs and Improve Operations

Nordic Baltic BioenergyBjörn Forsberg

RigaApril 14-15, 2015

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Nordic Baltic Bioenergy

  How Black pellets are made

  Selma: construction status, conversion scope, pellet transport & storage at port

  Safety in Operations: Advantages of Black vs. white

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Zilkha Black® Pellets—A Real Option for Power ProducersAdvanced wood pellet that is:•  Grindable•  Low-dust•  Water-resistant•  Stored outside•  High bulk density•  Can be burned direct in

existing coal power plants •  Co-fired up to 100%•  Reduced capital required

Certified sustainably harvested

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Zilkha Black® PelletTechnology

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What Is a Black Pellet?

  Zilkha Black® pellets are thermally conditioned biomass pellets  100% wood with no natural or artificial additives. NONE.

  The thermal conditioning process is well known. NOT TORREFACTION

  The pellet itself has mechanical and physical properties which are highly desirable for use in power plants to replace coal

  Specifically, Black pellets are harder than white pellets because when pelletized, the abundant free lignin melts and acts as a water resistant glue

  As a result Black pellets have reduced fines and very low dust compared to conventional white pellets. Not zero. But greatly reduced.

  Black pellets can be shipped, received, stored, conveyed, and milled just like coal

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Zilkha Technology at a Glance

Manufacturing of Zilkha Black® Pellets is similar to the production of standard white pellets, with the addition of our patented thermal conditioning step.

IntakeSawdust, wood chips, and first

thinning

DryingReduce moisture content from

ambient (~50%)to 6-10%

Proprietary Patented Zilkha

Thermal Conditioning

Milling & Pelletizing

Feedstock is resized then passed through dies to create

Zilkha Black® pellets

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Making Black Pellets

  Wood is chipped, sealed in a pressure vessel, and pressured with steam  After “cooking” briefly (5-15 min) the pressure is quickly released and the steam

pressure “blows” the material into a receiving tank  The conditioned material moves by conveyor to a standard pellet mill

  Wood is composed of cellulose, hemicellulose, and lignin (~1/3-1/3-1/3)  The thermal conditioning frees the lignin  Lignin is a natural waterproof glue which melts at ~125+ °C, a temperature which is

reached inside the pellet die  Results in a tight, hard pellet bonded together with a natural, waterproof glue  No additives of any kind are used.

HOW:

KEY:

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Thermal Conditioning Before and After

Hammer-milled wood particles before thermal conditioning

The result AFTER thermal conditioning: the wood is more easily pelletized and is “glued” using abundant lignin

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End Result: A Direct Replacement for Coal

How do Black pellets stack up vs. white pellets ?

  Harder and more brittle  Fewer fines  Less dust  Water resistant

Just Like Coal

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Selma Alabama USA, 275 000 tpy

Selma Plant Startup

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Selma Plant Undergoing Commissioning & Startup

Zilkha Thermal Conditioning

Island

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First Black Pellets from Selma

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Selma Rebuild = General Improvements + Black Conversion

General improvements:  New chip yard BRUKS (scale, truck dump, radial stacker, chip reclaim, scalper,

green chip resizing, new green feed delivery conveyors)   Dryer island (MEC dryers reconditioned, new powder fired hot gas generation

system from WTS powder burners)  Pelleting (reconditioned Andritz pellet machines, aspiration, pellet conveyors)  Out loading (more storage, de-dusting, truck loading station)

White to Black conversion:  Black pellet island (thermal conditioning and blow tank)  Post conditioning (dry grinding, delivery conveyors)

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Conversion to Black—Reroute Through Conditioning

ChipyardDryers

Pelleting

Coolers

Outloading

Resizing

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Adding Black Unit Achieves Conversion from White

Chipyard

Reroute Through

Thermal Conditioning

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New Thermal Conditioning Island

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Pellets Are Trucked from Selma to Mobile, Alabama

280 km from

Selma to Mobile

25 Metric Tonnes per

Truck

36 Trucks per Day

216 Trucks per Week

936 Trucks per Month

11 Hours of Unloading per Day / 6 Days per

Week

End-Dump Wood Chip

Trailer

Truck Loading System

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Terminal Operations in Mobile

Pellets received using truck dump dedicated to

Black pellets

Pellets stored in hopper

barges

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Barges Fleeted Prior to Mid-Streaming Onto Ships

Barge Fleeting

Area

Barge Fleeting

Area

Mid-streamShip Loading

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Reduce White Pellet Safety Risk by using Black Pellets

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White Pellet Risk Factors

Key areas where Black pellets have a storage and handling advantage:

  Self Heating Off-Gassing Dust

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  Dust = very real explosion risk

  Explosion mitigation takes capital beyond that required to handle coal

  Off-gassing of CO, CO2, and CH4 require venting during storage and transport

  Pellet pile self heating can lead to fires

White Pellets Taught Safety Lessons

Source: Staffan Melin. Safety in Handling Wood Pellets. 2008.

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University of Nottingham: Self Heating Not Present

  University of Nottingham  2 thermally conditioned

piles and 2 wood chip piles  6 month storage test

  Conclusion:  Thermally conditioned

Black pellets, both indoor and outdoor, saw no distinct increase in temperature. No evidence of self-heating.

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UBC: Dangerous Gas Emissions Greatly Reduced

Less methane:

WHITE

BLACK

Less carbon monoxide:

WHITE

BLACK

More oxygen:

BLACK

WHITE

  Zilkha Black® pellets tested at UBC were far less reactive than white pellets. Black pellets were found to have significantly reduced oxygen depletion

  Oxygen depletion is a significant operational issue. Extra workers and other special safety restrictions are required for workers entering white pellet storage areas

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Minimal Dust from Conveyor Drop

  Pellets drop several feet from final conveyor discharge at Zilkha’s Crockett plant

  No visible dust

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Parking Lot Drop Test Shows Minimal Dust

  Pellets stored outside in Europe

  Urban location sensitive to dust

  Pellets were exposed to a few days of rain

  Operator test was looking for dust

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Black Pellets are Water-Resistant which Means …

Zilkha Black® Pellets

compared to conventional white pellets

after brief exposure to

water

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Black Pellets Load Like Coal and No Problem with Rain

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Black Pellets Can Use Established Dust Suppression Technology

Water is a very effective, widely used method of dust suppression for coal. The same methods can be used for Black pellets. Just like coal.

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Water Spray on Coal at Transfer Points & Hoppers

Transfer Points

Hoppers

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Zilkha Black Pellet Outdoor Storage Experience

Canada Sweden

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Zilkha Black Pellet Outdoor Storage Experience

Coal

Black Pellets

Denmark France

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Summary  Zilkha’s Selma plant construction and commissioning complete—in startup  Selma proves conversion of white pellet plants to make Black pellets is

straightforward  White conversions to Black will accelerate Black pellet availability  The combination of conversions and new build Black plants provide geographic

diversity as well as multiple suppliers  Cooperative “backup” relationships and agreements will form a robust supply

system  Zilkha has an active license program for new producers as well as conversion from

white to Black  Zilkha Black pellets offer a low capital solution for power producers  Black pellets handle, store, and can be managed just like coal  Black pellets are a lower risk, cost effective option for power plant owners