FischerTropschAERGasifier

Production of Fischer-Tropsch fuels based on syngas from the AER gasifier Master Thesis

March 26, 2012


Stefan Hemetsberger – Vienna University of Technology

Supervision: Lasse Røngaard Clausen – Department of Mechanical Engineering, DTU Lyngby Hermann Hofbauer – Department of Chemical Engineering, Vienna

3 DTU Electrical Engineering, Technical University of Denmark

Fischer Tropsch Process in ASPEN PLUS


Fischer Tropsch Process

Advantages FT- Diesel:

+ no engine changes are required

+ no changes in distribution



• Low temperature process (210-250 ºC) – using Co- based catalyst – creating of middle distillates (diesel, waxes) – Slurry reactor

• High temperature process (320-350 ºC)

– using Fe- based catalyst – creation of shortchain products (gasoline, α-olefins, compounds

containing oxygen) – Fluidized bed



• Fischer Tropsch simulation data will be compared to experimental lab scale data from CHP Plant in Güssing


Güssing

• City in Austria

• 4000 inhabitants

• Self- sufficient energy supply

• Wood input of 1760 kg/h

• Heat energy (4,5MW) for district heating system covers >85% of demand

• Electric Power 2 MW

• Research for FT- diesel

• Future goal: whole district energy self- sufficient


Feedstock Biomass

• Because of Syngas production via Gasification in comparison to Fermentation -> Exact Composition less important

• Biomass = Wood:


AER- Gasification

• Absorption Enhanced Reforming – Dual fluidized bed reactor

Steam

Biomass

Product gas with H2 high content

Flue gas with high CO2 content

Bed material - Catalyst

Bubbling fluidized bed in gasification reactor

Circulating fluidized bed in combustion reactor

Air


AER- Gasification

• Gasification Reactor – Bubbling fluidized bed

Biomass bbbbbbbbbbbbbäääb

• Conditions: Temperature 600-700°C Pressure atmospheric

Steam

Biomass


AER- Gasification


Drying 100-150°C

Pyrolytic Devolization 200-650°C

Gasification 700-1000°C

Biomass Biomass dry

Char

Heat

Ash

Steam

Steam

Volatile matter (H2, CO, CO2, CH4, etc.)

Gaseous pyrolysis products

Product of char gasification


AER- Gasification


Biomass bbbbbbbbbbbbbäääb

Biomass Bi

• Conditions: Temperature 600-700°C Pressure atmospheric

• Volatile CO2 from WGS reaction CO + H2O CO2 + H2 (exothermic)

is absorbed by CaO (bed material)

CaO + CO2 CaCO3

calcium carbonate is formed

Steam


AER- Gasification

• Combustion Reactor – Circulating fluidized bed

Biomass Bi

• Conditions: Temperature 800-900°C Pressure 0,1 bar

• Regeneration of bed material CaO + CO2 CaCO3 (endothermic)

Bed material loaded: CaCO3 + ungasified char

Bed material revitalized: CaO + heat

Air


AER- Gasification

• Absorption Enhanced Reforming

Air Steam

Biomass



Bed material

Bubbling fluidized bed in gasification reactor

Circulating fluidized bed in combustion reactor


AER- Gasification

• Comparison to Fast Internally Circulating Fluidized Bed (FICFB) Process • FICFB (Güssing) same process but bed material is just for heat transport

no CO2 absorption

Biomass


AER- Productgas Cleaning

Steam

Biomass



Air

Fabric filter

Scrubber RME

Product gas

RME

particles tars water tars

Syngas


FT- Synthesis

• Process Güssing Lab Scale– Gas/Liquid conversion

Steam Reformer

Scrubber RME

Activated charcoal

Compressors

ZnO reactor

CuO reactor

FT reactor Condenser

Scrubber OGS

Cooler OGC

Off-gas Syngas


FT- Synthesis

• Scrubber

Steam Reformer

Scrubber RME

Activated charcoal

Compressors

ZnO reactor

CuO reactor


Scrubber OGS

Cooler OGC

Off-gas Syngas

RME

Aromatic compounds

H2O


FT- Synthesis

• Activated charcoal

Steam Reformer

Scrubber RME

Activated charcoal

Compressors

ZnO reactor

CuO reactor


Scrubber OGS

Cooler OGC

Off-gas Syngas

Activated charcoal converts H2S to elementary sulphur which is absorbed

Sulphur deactivates Co- catalyst in FT reactor !


FT- Synthesis

• Purification

Steam Reformer

Scrubber RME

Activated charcoal

Compressors

ZnO reactor

CuO reactor


Scrubber OGS

Cooler OGC

Off-gas Syngas

Purification to a sulphur content of <1ppm or even 60 ppb


FT- Synthesis

• FT reactor – 3 phase Slurry reactor

ZnO reactor

CuO reactor


Scrubber OGS

Cooler OGC

Off-gas

+ 30% less investment costs comparing to fixed bed + homogeneous temperature distribution

• Solid catalyst particle: Co- based • Liquid phase: waxes

Syngas

FT product

+ FT- reaction temperature is removed fast by waxes -> no deactivation of catalyst because of sintering + isothermal reactor -> higher temperature -> higher conversion rate


FT- Synthesis

• Condenser

Steam Reformer

Scrubber RME

Activated charcoal

Compressors

ZnO reactor

CuO reactor


Scrubber OGS

Cooler OGC

Off-gas Syngas

Condensing long hydrocarbons and water from product containing gas


FT- Synthesis

• Scrubber - OGS

Steam Reformer

Scrubber RME

Activated charcoal

Compressors

ZnO reactor

CuO reactor


Scrubber OGS

Cooler OGC

Off-gas Syngas

Removing FT waxes ->no packing blockage


FT- Synthesis

• Cooler - OGC

Steam Reformer

Scrubber RME

Activated charcoal

Compressors

ZnO reactor

CuO reactor


Scrubber OGS

Cooler OGC

Off-gas Syngas

Condensation of short hydrocarbon chains


Goal: Simulation of an industrial scale process for FT- diesel production based on FT- process in Güssing

Current state: Modeling AER gasifier in Aspen Plus

Ma

Thank you for your attention.

FischerTropschAERGasifier

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