Biomass- and coke oven gas based methanol production

Abstract: This study considers production of methanol as a motor fuel, generated from
coke oven gas at the steel mill SSAB Tunnplåt in Luleå. In addition,
different systems with a biomass gasification plant included are
considered. The produced synthesis gas is mixed with the coke oven gas to
enhance the methanol production. Different technologies for production of
the alcohol are applied. The selected techniques are based upon their
advantageous by economical and technical characteristics. The selected
systems are modelled in Aspen plus, which is a widely used process
simulation software. The resulting dimensions of streams, units and the
energy balances are subsequently used for the economic analysis.

Global warming caused by an increased concentration of greenhouse gases is
of major concern today. It is predicted that global warming will cause sea
level rise and other environmental impacts that may harm humans and nature.
The significant increase of greenhouse gases over the last 200 years is
almost entirely due to human activities and particularly due to combustion
of fossil fuels. By using biomass as fuel for production of methanol as
motor fuel, it would contribute to decrease the total green house gas
emission level. The coke oven gas which origins from fossil based coal,
could be used in a better manner as fuel for methanol production than for
increase the present electricity production at LULEKRAFT AB (LUKAB). That
is because the methanol production leads to a product with lower specific
CO2 emissions due to that the conversion- and total plant efficiency are
much higher.

The wood-pellets produced from sawdust at Bioenergi are to a large extent
exported from the county to heat and power plants, which purchase the
pellets to a low price. A better option would be to use the sawdust for
methanol production, which would be more profitable and could be used
within the county and thereby also minimize the transportation costs and
green house gas emissions.

The conclusion is that methanol produced from 400 GWh coke oven gas would
have a production cost in the range of 1,20-2,44 SEK/litre. Methanol
produced from both 420 GWh sawdust and the coke oven gas would result in a
production cost in the range of 1,20-2,70 SEK/litre.

The minimum methanol sale price was calculated via a fuel value analysis
which analyzed the fuel input value within the MEOH plant, LUKAB and
Bioenergi. The methanol produced from the coke oven gas would have a
minimum sale price in the range of 1,20-2,68 SEK/litre. Methanol produced
from both sawdust and coke oven gas would result in a minimum sale price in
the range of 1,28-3,17 SEK/litre.

The produced methanol from sawdust and coke oven gas could potentially
replace about half of the present gasoline demand in the county. This would
decrease the import of fossil based motor fuel considerable.