thought of combining H2 made of water and coal (or whatever C
containing material) into C in gigantic plants? The product is gasoline and the
raw material will be there for hundreds of years to come. The process already
exists since 1920s–1930s
and it is called Fischer–Tropsch synthesis. The infrastructure is already there and the
process is profitable even today.
The technology was invented in 1920s by two German chemists Franz Fischer and
Hans Tropsch. In the Second World War, German warfare was in part fueled by
Fischer–Tropsch liquids from coal. Most of Nazi Germany’s synthetic fuels were
produced by direct coal liquefaction using the process developed by German
chemist Friedrich Bergius (Nobel laureate in 1931). During the isolation period
because of its apartheid policy, South Africa produced fuels from coal using the
At first the raw
material is converted to synthesis gas (CO + H2) and then using
proprietary Fischer–Tropsch catalysts (cobalt) the synthesis gas is converted mostly to sulfur-free high-quality diesel and chemicals.
Fuel synthesis is a
proven technology since World War 2. In Hydrocarbon
Processing there was a piece of news that Chinese can produce synfuel that is
economic even with US$15 oil barrel (coal to liquids, CTL).
Shell and Sasol in
particular have a lot of interests in gas-to-liquids (GTL) from natural gas.
Shell already has a commercial GTL plant in Malaysia and new GTL plants will be
commissioned in Qatar and Nigeria. The most interesting in long term, however,
is the BTL (biomass to liquids) development (google: Choren, sundiesel, sunfuel,
synfuel, Volkswagen, BTL).
conditions fuel should preferably be liquid. Fischer–Tropsch diesel is low-sulfur fuel.
Because of its high quality, Fischer-Tropsch diesel has a price advantage of
about US$8 a barrel. See below gasoline and hydrogen vehicle, when fuel is at
Various sources can be used to
produce synthesis gas, and various products can be made from synthesis gas.
Fischer–Tropsch products: diesel, gasoline and chemicals, are
just one choice. See the chart below:
Fischer–Tropsch biodiesel and cellulosic
ethanol have fairly good fossil energy balance and they do not compete directly with
There are three routes to manufacture
biodiesel: 1) from vegetable or waste food oils and some alcohol to produce
ester (biodiesel), 2) from vegetable or waste food oils or animal fats and
hydrogen to produce high-cetane biodiesel (Neste's NExBTL) and 3) from biomass
via synthesis gas and Fischer-Tropsch to produce more dinodiesel-like biodiesel,
but sulfur free. The latter involves the manufacture of H2 from biomass, and one
alternative is to stop there and purify the hydrogen and use it as a fuel (see
Gas to liquids
(e.g. stranded natural gas fields), coal to liquids and biomass to liquids using
Fischer–Tropsch technology may be the answer for at least some decades after the
oil era –
or in the near future after the peak oil.
The abundance of coal
and the simple product, diesel/gasoline, make it possible to use the same
engines and infrastructure as today. It may be a good enough reason to choose
coal to oil rather than hydrogen.
of coal to oil Fischer–Tropsh is higher CO2 emissions per MJ
output. The F–T
products are also more expensive than petroleum based gasoline and diesel. In
short term (10 to 20 years), not enough Fischer–Tropsch capacity can be built in case the
consumption increase will be as big as predicted and the oil production cannot
meet the demand. We may already have reached peak oil (read about the peak oil
math by Kenneth S. Deffeyes) or we will soon reach peak oil. The coming crisis is about
the shortage of liquid fuels. You better prepare for three-digit crude prices
for one barrel.
Sasol's break-even price
is about US$22 (crude market price) for coal to liquids using Fischer-Tropsch.
It may be low, because they have the best and proven F-T technology with very
low cost coal.
Natural gas is very
suitable for the syngas production because of its purity and good C to H ratio.
Coal has a lot of impurities, sulfur etc. There is lack of natural gas in some
decades and that is why coal should be chosen for Fischer–Tropsch.
However, Fischer–Tropsch could be the best choice for stranded gas, where pipelines and
LNG infrastucture are uneconomic.
The main raw material
for the U.S. chemical industry is natural gas and in order to maintain this
situation natural gas reserves should not be used in energy generation (heat,
electricity, gasoline, hydrogen).
There are newer
statistics, but I had the book of Weissermel and Arpe (Industrial Organic
Chemistry) from 1993 on my reach. It says about the fossil reserves:
Natural gas 60–70 years
Coal. "A study by the
Leningrad Geological Institute reached a similar conclusion: even at the current
rate of growth, the minable hard and brown coal reserves would be adequate for
at least 5000 years."
Oil 40 years (proven)