Fisher-Tropsch diesel production in a well-to-wheel perspective; a carbon and energy flow analysis

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Fisher-Tropsch diesel production in a
well-to-wheel perspective a carbon and energy
flow analysis

• Oscar van Vliet, Andre Faaij, and Wim Turkenburg
• Unit Science, Technology and Society
• Copernicus Institute Utrecht University
• w.c.turkenburg_at_chem.uu.nl
• Conference Kennis in Zicht, NWO/SenterNovem
• Amsterdam, 18 January 2007

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Global CO2 emissions from fossil fuels (in 2002,
forecast for 2030)
Source IEA, WEO, 2004
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Some challenges in transportation

• Transportation contributes 21 of GHG emissions
  in Europe more than 90 due to road traffic
  these emissions have grown by 22 in period
  1990-2002.
• Also other emissions (fine particulate matter,
  volatile organic compounds, and others).
• Relatively high and unstable oil prices.
• Insecurity about stability oil supplies.
• Doubts about sufficiency oil stocks on the long
  term.
• gt Search for alternatives like new and cleaner
  fuels.

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Characteristics of different energy sources for
road transport (EU)

) Biofuel figures are those for the cheapest
production techniques ) Assuming oil price of
48/barrel and 70/barrel respectively
Source European Committee An energy policy for
Europe Brussels, January 2007.
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Focus on FT-diesel

• In this study the potential of Fischer-Tropsch
  diesel as a replacement of conventional diesel is
  investigated.
• FT-diesel is compatible with existing vehicles
  and infrastructure.
• Can be produced from wide range of feedstocks
  (like natural gas, coal, biomass).
• Fuel doesnt contain sulphur or nitrogen.
• Share diesel in EU is expected to grow
  substantially.
• Marginal production of conventional diesel is
  stretched and relatively inefficient at
  refineries in EU.
• gt Situation presents potential entry point for
  FT diesel.

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Fischer-Tropsch conversion

• Gasification of feed stocks, followed by gas
  cleaning.
• Synthesis gas catalytically converted to
  hydrocarbons.
• FT fuel production first started in Germany in
  1935 nine CTL-plants were built, and shut down
  in 1945.
• After WWII, FT-fuels primarily made in
  South-Africa.
• At present, many companies are working on CTL and
  GTL plants (e.g. Shell, Sasol Chevron, Total,
  Exxon).
• Large scale GTL activity underway in especially
  Quatar large CTL plants planned in China and
  India BTL is developed in e.g. Germany.

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Impact on local air quality

• Driving our existing vehicle fleet on (blends of)
  FT fuels will provide significant benefits to
  local air pollution.
• Emission reductions applying Shell GTL FT-diesel
  vs. conventional diesel in a standard VW Golf
  vehicle
• NOx -6.4
• PM10 -26 to -28
• Hydrocarbons -63
• CO -91

Source Seyfried, 2005
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Research questions

• Aim of study to trace a development path for FT
  diesel, based on a well-to-wheel (WTW) approach
  to compare different chains on costs, land use
  and GHG emissions.
• Study is done by bottom-up simulations, applying
  existing and emerging technologies, using data
  from literature.
• Research questions
• What are the main determinants of GHG emissions
  and costs of FT based chains?
• What are desirable chains that can replace
  conventional diesel production?
• Is it possible to make credible recommendations?

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Fischer-Tropsch conversion plant

• Plant capacity used in this study 400-2000 MWth
  (input).
• Note 2000 MWth (input) plant produces 14,000
  barrels/day )
• Main components of the plants investigated
• 1. Power island, for heat balancing and
  electricity supply.
• 2. Pre-treatment of the feedstock (biomass
  coal).
• 3. Syngas production, using a gasifier and/or a
  reformer.
• 4. Gas cleaning, to remove tar and sulphur.
• 5. Water-Gas Shift reaction (WGS), to provide
  the required
• H2/CO ratio for the FT synthesis.
• 6. Capture and Storage of CO2 from the syngas
  (CCS).
• 7. Fischer-Tropsch synthesis to produce FT fuel
  (diesel).
• 8. Upgrading of the product mix, by
  hydro-treating and -cracking.

) For comparison two refineries in the
Rotterdam area each produce 400,000 barrels / day
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Syngas production

• Gasifiers (to produce syngas) applied in this
  study
• - Fluidized Bed gasifier (manufacturer IGT)
• - Entrained Flow (EF) gasifier (manufacturer
  Shell)
• - Multi-stage gasifier (manufacturer CHOREN)
• Note all gasifiers are oxygen-blown (requiring
  an Air Separation Unit) and pressurized (20 bar
  or more).
• In addition Syngas production by methane
  reforming current plants often use auto-thermal
  reformers (ATR).
• Selection of gasifier ultimately depends on
  design choices (scale, feedstock, product mix).

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FT synthesis

• Three FT processes evaluated in this study
• Two FT processes have significant market share
  now
• - Shell Middle Distillate Synthesis process
• - Sasol Slurry Phase Distillate process
• Both were developed since the 1980s and are used
  commercially since the 1990s. In both cases
  upgrading of the product is required.
• A combination of the Sasol process with a Shell
  Hydro Paraffin Cracker unit may provide an
  optimal FT synthesis plant (regarding costs,
  product flexibility and yield). It is assumed
  that this process may come available in 2015.

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Feedstock supply

• Bituminous coal shipped to Europe with CTL
  conversion in Rotterdam. Cost coal 2.01 Euro/GJ.
• Natural gas produced and converted (GTL) in
  Middle-East diesel shipped to Rotterdam. Cost
  natural gas 0.93 Euro/GJ.
• Biomass is collected from farming region in
  Canada (1.9 Euro/GJ for forestry residues),
  Eastern Europe (4.9 Euro/GJ for willow or
  poplar), or Latin America / East Africa (2.5
  Euro/GJ for eucalyptus).
• Conversion of biomass to intermediates two
  production processes considered here,
  conventional pellets production and TOPs (using
  torrefaction).

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Well-to-wheel chains

• Eventually 24 WTW chains investigated (20 FT
  diesel chains and 4 conventional diesel reference
  chains).
• WTT Seven basic well-to-tank (WTT) chains
  investigated
• 1. Crude oil ? shipped to Western Europe (WE) ?
  refined to diesel (conventional or fossil
  diesel).
• 2. Natural gas ? converted to FT fuel ? shipped
  to WE.
• 3. Coals ? sent to port ? shipped to WE ?
  converted to FT fuel.
• 4. Biomass ? converted to pellets ? sent to port
  ? shipped to WE ? converted to FT fuel.
• 5. Biomass ? converted to pellets ? sent to port
  ? converted to FT fuel ? shipped to WE.
• 6. Biomass ? converted to FT fuel ? sent to port
  ? shipped to WE.
• 7. Biomass ? converted to TOPs ? sent to port ?
  shipped to WE ? converted to FT fuel.
• TTW diff. config. of vehicles investigated
  (2005, 2015, 2030).

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Results
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Results