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Operations Summary of a Commercial Biomass Gasifier Generating a Clean, Combustible Gas for Industrial Heat or Repowering an Existing Power Boiler

Frontline GasifierBenson, MN

Jerod Smeenk2011 TAPPI IBBC Conference

March 15, 2011

CVEC Ethanol Plant – Benson, MN

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Chippewa Valley Ethanol Company

• Located in Benson, MN• 48 MMGY corn ethanol plant• Innovative farmer co-op

– Produce alcohol for two different vodkas– Largest organic alcohol producer in the US

A Strategic Decision in 2005 Driven by:

• Concern about natural gas price trend vs potential biomass energy lying in co-op members’ fields (keep $13M/yr energy costs ‘at-home’)

• Interest in improving fossil energy balance of the plant– Probability of carbon monetization in the US– Make the ethanol more “renewable”

• Desire to participate in cellulosic biofuel technology



CVEC Design Considerations• Displace 90% of natural gas with renewable biomass

– Disruption free operation of existing ethanol plant– ~ 280 ton/day biomass required

• Enable biomass feedstock flexibility– wood, cobs, stover, grass, oil or glycerin (liquid injection)

• Utilize existing energy assets– Retrofit existing “Gas Fired” appliances– Distributed gas integration network required to fire TO/HRSG,

ICM drum dryer, Barr-Rosin ring dryer, package boilers– Natural gas & propane backup required

• Platform suitable for future BTL efforts– Syngas-to-ethanol platform– Low tars



Frontline’s Gasifier Systemat Chippewa Valley Ethanol Company

• Phase 1: – 75 ton/day (40 MMBH)– high efficiency particulate

removal before combustion– retrofit existing gas-fired boiler

• Phase 2: – add CLEANGAS™ system to

eliminate tars– distribute gas to multiple

burners

• Phase 3: – Upgrade system to achieve

280 ton/day (> 90% NG displacement)



What is Gasification?

7

CO H2

Also,CH4, CO2,H2O

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



8

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”



Gasification & Combustion(Gas Integration vs. Steam Integration)

• Gasification allows piping of combustible gas to multiple locations for integration with existing appliances– Change natural gas burner to a multi-fuel burner on boilers, dryers,

and TO’s– Avoid stranded capital, retrofit existing appliances

• Gasification allows gas independent interface, not steam dependent– Instant, robust natural gas or LP backup– Decouples plant reliability from energy system avail.– Protects and values your on-line production time



Gas Integration cont’d

10

• Gasification allows gas conditioning and cleanup before firing gas appliance (boiler, dryer, etc.)– Gas conditioning (emissions control) done at one location, not each

individual appliance– Protect equipment from particulate and alkali– Smaller filtration system (pre-combustion gases)

• Bridge to ligno-cellulosic ethanol & products– Builds a biomass market– Convert from air blown (producer gas) to oxygen blown (syngas)



CVEC Gasification System

11

BIOMASS DG DRYER

BAGHOUSEFILTER

AIR

CHAR-ASHCOOLING,DEDUSTING,…LOAD-OUT

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

GA

SIF

IER COOLING

(steam generation)

BOILER



METERINGVESSEL

LOCK HOPPERVESSEL

BIOMASSSTORAGE

SILO

One Gasifier Many Multi-fuel Burners

DRYER #1

DRYER #2

T.O./HRSG #1

Etc….

MULTIGAS BURNERSFRONTLINE GASIFIER

COEN MULTIGAS BURNER

• Deliver CLEANGAS® to the burners– Cleaner boiler means less production down-time

• Downstream PM control not required– pre-combustion filter is >99.9% efficient

• Avoids new boiler capital & complexity– Expensive solid fuel boilers, steam appliances not required



NAT GAS BACKUP

Gasifier System



BiomassSilo

Char/AshLoad-Out

GasifierBuilding

Gas Product Pipe LineMCC

Air Blower



Gasifier

Filter

Boiler

Flare Test

Feedstock Unloading

Gasifier

Gasifier System Design

• Pressurized (up to 60 psig)• Bubbling Fluidized Bed• Scalable – units > 1000 tpd• Fuel flexible – omnivorous• Simple, robust, and stable

operation• Minimizes footprint • Up to 10 : 1 turndown



Advanced Gas Cleanup

PMFree Gas™ – high efficiency hot gas filtrationCommercial demo at CVEC

Removes bad actors from producer gas prior to combustion

>99.999% particulate matter (PM) down to < 2 mg/Nm3

including alkali metals and alkali chlorides

~95% capture of chloride (HCl)

~90% sulfur capture



CVEC Operations Cost atPhase 1 Capacity



$‐

$1.00

$2.00

$3.00

$4.00

$5.00

$6.00

Natural Gas Wood Cobs RDF

$5.00

$5.91 $5.80

$4.02

Cost per million Btu

Includes:•Fuel•Labor•Electricity•Maintenance

CVEC Operations Costs Ex Capital



$‐

$1.00

$2.00

$3.00

$4.00

$5.00

$6.00

Natural Gas

Wood Cobs RDF

$5.00

$5.91 $5.80

$4.02

$4.72 $4.61

$2.83


40 MMBH

160 MMBH

Operating, Feedstock, & Amortized Capital Costs



$‐

$1.00

$2.00

$3.00

$4.00

$5.00

$6.00

$7.00

Natural Gas RDF Wood


Fuel

Opex

Capex

$5.15

$4.22

$6.29

400 MMBH$5/MMBtu nat gas$30/bd‐ton RDF$70/bd‐ton wood

Lessons learned by CVEC

• Feedstock– Biomass is not always a commodity - requires

proactive sourcing and solid supplier relationships– Wood is not wood is not wood– Increased moisture = decreased efficiency– Bubbling fluidized bed has proven its flexibility - wood,

corn cobs, glycerin and corn oil feedstocks– Should have permitted the gasifier for a wide range of

feedstocks




• Gasifier Operation– Process has worked per design intent– Component reliability issues have caused the most

headaches - valve selection is critical– Thermal cycling destroys refractory– Fouling of the Producer Gas Cooler with certain

feedstocks & operating conditions– Multi-fuel burner has worked well




• Char-ash– Residual ash and unconverted carbon– Must establish proper handling techniques – it is a

combustible dust!– Obtained beneficial use permit that authorizes land

application as a soil amendment



CVEC Gasifier Status• Have logged thousands of operating hours –

but displacement of natural gas with wood gas not economical

• Working to permit the system to use lower cost waste feedstocks

• Anticipate emissions testing on engineered fuel (sorted MSW) this summer



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

25APTURE THE ENERGY | RELEASE THE POTENTIAL


frontline gasifier benson, mn operations summary of a ... · – smaller filtration system...

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