Klas J. Andersson, Poul Erik Højlund Nielsen - IFC 2012

Options for tar reforming in biomass gasification

Gasification

COH2

CO2

BiomassNatural gasCoalWaste

HydrogenMethanol

DMEGasolineSNGPowerAmmoniaSyngas

Haldor Topsøe A/S- A global supplier of catalysts and technologies

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Rio

Introduction to biomass gasification

� Biomass gasification (except black liquor) is usually based on fluidized bed.

– Carbona, FW, Repotech etc

– The outlet temperature (800-900°C) is restricted by ash stickiness

� Tar (C6+-PAHs), ~500 ppm – 1 vol %

– Energy loss, fouling, waste water treatment, downstream catalyst deactivation etc.

� H2S: 20-200 ppm

BIOMASS

ASH

GASIFIERTAR REFORMER

Tar reforming

� 1. Increased gas production

� 2. Convert polyaromatic components to an extent that allows the syngas to cool for further processing without fouling or precipitation

� 3. Utilize the high temperature levels from gasification for increased efficiency

Tar reforming

� Tar reformerSyngas

Treated Syngas

750-950°C1-10 bar

Easy:H2O + CO ⇄ H2 + CO2H2O + COS ⇄ H2S + CO2Always (almost) in equilibrium

Difficult in 20-200 ppm H2S:CH4 + H2O ⇄ CO + 3H2CnHm + H2O → CO + H2Tar + H2O → CO + H22NH3 ⇄ N2 + 3H2

strongly endothermic

Links to neighboring HTAS technologies

� Similarities: Reforming of higher hydrocarbons

– Prereforming of heavy NG

– Naphtha steam reforming

– Sulfur passivated reforming (SPARG)

Hot gas filters

BIOMASS-FEED

ASH

GASIFIERTAR REFORMER

AIR / O2 / H2O

DUST

HOT GAS FILTER

SYNGAS CLEAN-UP

5 -10 mg dust / Nm3

Quench gas

Hot gas filters

� Pressurized gasification = yes

– ”clean” tar reforming

� Atmospheric gasification = less likely, huge filter vessel

– ”dirty” tar reforming

Choice of catalyst in ”dirty” vs. ”clean” tar reforming: coated monolith vs. catalyst pellets

Monolith, coated w/ catalyst Catalyst pellet, bulk catalyst

* Low ∆P: can handle dusty environments.

* Low density of active material.

* Higher ∆P: dust sensitive.

* High density of active material.

Tar reforming layouts

� Dusty tar reformer

– Combined heat and power applications

� Low pressure drop

� Coarse clean up

� Avoiding dust accumulation is the major challenge

Tar reforming layouts

Clean tar reformer

– Chemicals: SNG, gasoline etc.

– Higher catalyst load

– Clean syngas

– Can design to preserve or convert methane

Heating options in clean tar reforming

Direct

CMD

Syngas

Oxygen

Treated Syngas

Indirect (SPARG)

Clean vs. dirty tar reforming, pros and cons

� Clean, pressurized � Chemicals, from SNG to BTL+ Increased range of operability, flexibility

+ High poison capacity

- Higher O2 consumption (filter temperature)

- Dust sensitivity

� Dirty, atmospheric � Combined Heat and Power (CHP)+ Largely dust insensitive, high alkali content

+ High Tinlet

- Limited flexibility

HTAS tar reforming activities

� Commercial projects,

collaboration with Carbona

– E.On, pre-FEED Bio2G, SNG (200 MWLHV-CH4)

– Skive Fjernvarme, CHP (20 MWth)

� Gas Technology Institute pilot (5 MWth)

– Tests financed by E.On and UPM

– Proof of concept & design basis

� Laboratory tests on model gases

Learned

� Tar reforming economy

� Opex: ~Cost neutral

– Increased gas production

� Competitive compared to washes (bio diesel, OLGA etc)

Wood to GasolineWood to Gasoline DemonstrationDemonstration ProjectProject

OXYGEN

Green Gasoline From Wood Using Carbona Gasification and Topsoe TIGAS Processes

BIOMASS

ASH

GASIFIERTAR REFORMER

BIOMASS

ASH

GASIFIERTAR REFORMER

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BIOMASS

GA

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ASH

http://www.energy.gov/news2009/releases.htm

GasCleaning

Gasoline Synthesis

MeOH / DMESynthesis

Wood to GasolineWood to Gasoline DemonstrationDemonstration ProjectProjectGreen Gasoline From Wood Using Carbona Gasification and Topsoe TIGAS Processes

Thank you!