Paper Mill Repowering with Gasification · Package Boiler Firing on Producer Gas • Particulate free producer gas enables use of standard gas package boilers • Low maintenance

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Paper Mill Repoweringwith Gasification

Frontline GasifierBenson, MN

Jerod Smeenk2011 TAPPI IBBC Conference

March 14, 2011

Repowering Options –Looking Inside the Box

• Kiln – replace fossil fuel with liquid or gaseous renewable fuel– Existing resources – tall oil– New sources include pyrolysis oils or producer gas derived from

biomass or waste feedstocks

• Steam generation – replace worn out or low efficiency wood boilers with new, high efficiency steam generation equipment

• Electricity - displace utility power (likely fossil based) with internally generated renewable power in a power only or combined heat and power approach with steam generation



Repowering Options –Looking Outside the Box

• Electricity – use existing infrastructure to generate renewable power– Green-Brown Arbitrage – value of REC’s?– Long term PPA with local utility

• Biorefinery– Shift some or all of the mill’s products to fuels and

chemicals– Leverage existing brown field site with established

feedstock supply chain, feedstock site infrastructure, regulatory permits, labor pool, and utility interconnects



Why Repower?• Reduce operating costs and exposure to fuels

market volatility• Utilize local resources to keep energy dollars

close to home• Reduce carbon footprint• Improve public image by being renewable• Diversify product portfolio to mitigate risks

associated with single product/industry



Gasification in P&P Industry

• Over thirty year history of P&P applications – Gasification of mill residue and wood for thermal

energy – Gasification of black liquor for syngas production and

chemical recovery



What is Gasification?

6

CO H2

Also,CH4, CO2,H2O

Direct Gasification (Air or Oxygen)Indirect Gasification (Heat Exchange)

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7

Gasification is a Thermochemical Process• CombustionFuel + Excess Air → Heat + Hot Exhaust Gas + Ash

• Direct GasificationFuel + Limited Air→ “Producer Gas” + Heat + Char-ash + “Tar”Fuel + Limited Oxygen→ “Syngas” + Heat + Char-ash + “Tar”

• Indirect Gasification and PyrolysisFuel + Heat → “Syngas” or “Pyrolysis Gas” + Char-ash + “Tar”



When Should GasificationBe Considered?



Wood feedstock MSW-derived feedstock

Kiln fuel X XBoiler fuel XKiln & boiler fuel X XBiorefinery X X

Frontline Gasification System

9

BIOMASS LIME KILN

BAGHOUSEFILTER

AIR

CHAR-ASHCOOLING,DEDUSTING,…LOAD-OUT

PRODUCER GAS(H2, CO, CH4, H2O, CO2, CXHY, N2)

GA

SIF

IER

METERINGHOPPER

2nd STAGECOOLING(steam generationor hot air tobiomass dryer

LOCK HOPPER

1st STAGECOOLING(heated air to gasifier)

BIOMASSDRYER BOILER



Feasibility Study• Repower objectives include

– Reduce operating expenses in the power island by lower fuel cost and higher conversion efficiencies

– Decrease their carbon footprint through eliminating use of fossil fuels

– Improve public relations by having a totally ‘green’product

– Learn about gasification for possible future biofuel applications



Repower using producer gas• Lime recovery kiln

– Replace existing multi-fuel kiln burner (fuel oil, natural gas, tall oil) with a new burner that could use all those fuels AND producer gas

– New burner required because the low energy density of producer gas requires large volumes of gas

• High pressure package boiler– Generate power in an underutilized condensing

steam turbine– Tie into mill steam header to facilitate scheduled

maintenance of mill boiler fleet



Lime Kiln Firing Producer Gas• Flame temperature – adequate flame temp• Heat transfer – producer gas flame

emissivity slightly less than natural gas• Gas volume – with 15% MC feedstock,

estimated 13% increase in flue gas flow rate– Increase in kiln flue gas was deemed manageable

with existing ESP and induced draft fan– Biomass dryer required to condition feedstock to

15% MC target



• Particulate in producer gas– If present can contribute to emissivity for radiant

heat transfer in the kiln, but we weren’t convinced it was essential to successful heat transfer

– If present will result in lime contamination– Quality of mill products may require high purity lime

in which case lime purge is expensive and prohibitive



Lime Kiln Firing Producer Gas

Package Boiler Firing on Producer Gas

• Particulate free producer gas enables use of standard gas package boilers

• Low maintenance – removal of contaminants from the producer gas eliminates boiler fouling and corrosion

• Fuel flexibility – able to operate on producer gas or natural gas

• High availability – fuel flexibility provides very high on-stream time



Package Boiler Firing on Producer Gas

• Low emissions – proper combustion to minimize formation of NOx emissions that otherwise would result from combustion of ammonia (NH3) in the producer gas



Project Economic Results • Detailed economic analysis to establish

CAPEX, OPEX, and projected IRR• Breakdown of CAPEX

– ~ 44% for gasifier system– ~ 36% for biomass dryer– ~ 9% for wood yard upgrades– ~ 11% for package boiler and trim



Project Economic Results • Project IRR fell a few points short of the

internal hurdle rate; included ITC to reduce CAPEX

• The mill is still interested in performing the project but need to have financial fundamentals change– Increased fossil fuel costs– Lower cost feedstocks– Reduced CAPEX



Repower Economics



0%

5%

10%

15%

20%

25%

30%

35%

$3.00 $4.00 $5.00 $6.00 $7.00

Ann

ual Cash Flow

, % of Invested Ca

pital

Fuel Gas Value, $/MMBtu

Effect of Feedstock Cost and Fuel Gas Value on ROI

$2/MMBtu

$3/MMBtu

$4/MMBtu

$5/MMBtu

400 MMBH Biomass Gasifier, Including Dryer

Biomass Fuel Cost

Repower Economics



2

3

4

5

6

7

8

9

10

$3.00 $4.00 $5.00 $6.00 $7.00

Simple pa

yback, years

Fuel Gas Value, $/MMBtu

Effect of Feedstock Cost and Fuel Gas Value on ROI

$0/MMBtu

$1/MMBtu

$2/MMBtu

$3/MMBtu

400 MMBH Biomass Gasifier, Including Dryer

Biomass Fuel Cost

Summary• Natural gas and feedstock prices dictate plant

economics• Biomass is uniquely suited among renewables

for providing low carbon gaseous fuels• True gasification provides the opportunity to

utilize existing gas appliances (gas integration) and provide instant natural gas backup to protect plant operation

• Energy dollars directed to local economy instead of foreign countries

• Biorefinery optionality for biofuels productionCAPTURE THE ENERGY | RELEASE THE POTENTIAL


Frontline BioEnergy, LLC

1421 S. Bell Avenue, Suite 105Ames, IA 50010

515-292-1200www.frontlinebioenergy.com



Documents

Paper Mill Repowering with Gasification · Package Boiler Firing on Producer Gas • Particulate free producer gas enables use of standard gas package boilers • Low maintenance