6. Recent technological advances
6.1. Current industrial status
Olah et al. (2011)discussed the current industrial status of
methanol production from CO2; this state-of-art is represented here. A major milestone was achieved when Lurgi
AG and Sud–Chemie together developed a highly active and
selective catalyst for producing methanol from CO2 and H2
atT= 260
◦
C. The activity of this catalyst decreased at about
the same rate as the activity of the commercial methanol
synthesis catalyst (Goehna and Koenig, 1994). In another
major development, the first pilot plant for the production of
methanol (50 kg/h) from CO2and H2was built in Japan using a
SiO2-modified Cu/ZnO catalyst. Recycling the feed produced a
space-time yield of methanol around 600 g/(L h), with 99.9%
selectivity over 8000 h operation at 250
◦
C and 5 MPa (Saito,
1998). Yet another pilot plant producing methanol from CO2
and H2 with an annual capacity of 100 tonnes is being built
by Mitsui Chemicals in Japan. To accomplish this target, H2
will be generated by photochemical splitting of water using
solar energy (Tremblay, 2008). For the first time, a liquid-phase
methanol synthesis process was also developed, which allows
aCO2and H2conversion to methanol of about 95% with very
high selectivity in a single pass (Air Products, 2003). Then, the
first commercial CO2to methanol recycling plant using locally
available cheap geothermal energy is presently being built
after successful pilot plant scale operation in Iceland by the
company Carbon Recycling International. This plant is based
on the conversion of CO2, a significant by-product accompanying local geothermal energy sources or industrial sources
(aluminium production). H2is produced by water electrolysis
(vide infra) (Shulenberger et al., 2007).
The technical feasibility of methanol production from CO2
has also been demonstrated in pilot plants using a two-step
approach, viz. KIST (CAMERE) process (reverse WGS separate from methanol synthesis) or a single step approach proposed
by NIRE/RITE (the two stages integrated in a single reactor)
(Centi et al., 2008). The first approach seems preferable in
terms of higher catalyst productivity, lower gas recycle and
reactor size (Centi and Perathoner, 2009).
Very recently, researchers at the Institute of Bioengineering
and Nanotechnology (IBN) in Singapore used organocatalysts
to activate CO2in a mild and non-toxic process for producing
methanol. Certainly, all these developments are very encouraging.