[ e-methanol ]
Methanol Distillation Column
Refrigerant in
Refrigerant out
Reflux drum
Enriching Section
Reflux
Pure methanol
Crude methanol
Stripping Section
Vapor ( methanol and water ) return to column
Reboiler
Steam in Steam out
Residual water
Figure 2 . Methanol distillation column
Delegated Acts for RFNBOs , it achieves at least a 70 % reduction in greenhouse gas emissions compared to the reference fuel .
E-methanol production
The most mature and simplest technology for e-methanol production involves the production of hydrogen using water electrolysis powered by renewable electricity and its combination with CO 2
. The e-methanol synthesis process is very similar to the production of methanol from fossil fuel-derived synthesis gas , which ensures a high degree of technological maturity ( TRL 8 – 9 ). Slight differences such as a higher water formation need to be addressed ; however , catalyst providers have already developed materials to address this issue .
To produce e-methanol , the electrolysis process is complemented by a catalytic reactor where CO 2 hydrogenation takes place . Key components of a methanol plant include the reactor , distillation columns , gas compressors ( H 2 and CO 2
), and auxiliaries ( cooling and other process elements ), as shown in Figure 1 .
In terms of chemistry , methanol synthesis via CO 2 hydrogenation can be explained by three fundamental equilibrium reactions : CO 2 hydrogenation ( 1 ), reverse gas-water shift ( 2 ), and CO hydrogenation ( 3 ).² , ³
CO 2
+ 3H 2
↔ CH 3 OH + H 2
O ∆H ° = -49.8 kJ / mol ( 1 )
CO 2
+ H 2 ↔ CO + H 2
O ∆H ° = 41.2 kJ / mol ( 2 )
CO + 2H 2
↔ CH 3
OH ∆H ° = – 91.0 kJ / mol ( 3 )
From a thermodynamic point of view , the hydrogenation of CO 2 to produce methanol
( CH 3
OH ) is most efficient at low temperatures and high pressures . The adequate catalysts for the hydrogenation of CO 2 to methanol are
32 Hydrogen Tech World | Issue 20 | February 2025