Environmental Engineering Reference
In-Depth Information
The lignocellulosic feedstock (530 ktonnes/a) is pretreated through an acid catalyzed
hydrolysis step which splits the raw material in 2 flows: a solid flow containing cellulose and
lignin and a liquid flow containing the hydrolyzed C5 sugars. The pretreatment occurs at
temperatures higher than 160°C and with a reaction time of 2-10 minutes (Sun and Cheng,
2002). The liquid flow is made of C5 sugars (xylose and arabinose monomers coming from
hemicellulose hydrolysis with an efficiency of 95%) which are treated with a dilute sulfuric
acid solution at low temperature for a short period of time. The product output is furfural,
obtained with an efficiency of 90% by the following reaction: C
5
H
10
O
5
→ C
5
H
4
O
2
+ 3H
2
O
(Kaylen et al., 2000).
Furfural is then converted to the following products (Kamm et al., 2006b; Vazquez et al.,
2007):
Figure 12. Conversion of furfural to MTHF via methylfuran.
•
70% to the fuel additive methyltetrahydrofuran (MTHF) by reduction with H
2
via the
intermediate methyl furan, as illustrated in Figure 12 (1
st
reaction: C
5
H
4
O
2
+ 2H
2
→
C
5
H
6
O + H
2
O, molar efficiency 80%; 2
nd
reaction: C
5
H
6
O + 2H
2
→ C
5
H
10
O, molar
efficiency 95%; both reactions needs a Ni catalyst; overall yield 76%);
•
15% to furan resins, made by polymerization of furfural, furfuryl alcohol or other
compounds containing a furan ring;
•
15% to fumaric acid (FUMA) by oxidation (followed by opening of the furan ring) in
presence of a V
2
O
5
catalyst (C
5
H
4
O
2
+ 2O
2
→ C
4
H
4
O
4
+ CO
2
) (Figure 13).
Figure 13. Conversion of furfural to FUMA via oxidation.
