Hydrogen Tech World February 2025 | Page 34

[ e-methanol ]

Pure methanol

Figure 3 . Process flow diagram of the e-methanol production process

refining , eliminating possible heavy by-products such as fusel oil ( a mixture of undesired alcohols ) and water .

column reboiler by condensation . This reduces the net energy requirement of the purification system ( Figure 3 ). 4

On the other hand , there is the possibility of using three distillation columns . This alternative is more expensive in terms of investment but more economical in terms of operational costs , as it reduces the heat demand via heat integration . In this distillation strategy , the topping column is accompanied by two columns : a pressure column and a refining column . The pressure column is operated at a higher pressure than the refining column , and the product from the topping column heads ( methanol vapor ) can be used to provide the necessary heat to the refining

Finally , a single distillation column can be installed for methanol purification if it is to be used as a fuel . This configuration would result in a lower methanol purity but high enough to be used as a fuel for energy purposes ( 95 % vol .). 4

Costs and consumptions of e-methanol plants

Methanol plants investments are not negligible ; however , in a Power to X plant , these can still represent less than 30 % of the total investment compared to the

34 Hydrogen Tech World | Issue 20 | February 2025