Direct Pervaporation of Ethanol from Fermentation Broth
In 2013 Gaykawad and coworker reported their studies on a novel approach for using pervaporation in dehydration of wet ethanol. In these experiments direct pervaporation of ethanol from lignocellulosic
|
Membrane |
Temperature (°С) |
Total flux (kgm-2 h-1) |
Separation factor |
Selective layer thickness used in permeability calculation (pm) |
Water permeability (kmolmm-2 s_1 kPa1) |
Reference |
|
PVA composite membrane (Deutsche Carbone AG/GFTa) |
60 |
0.14 |
170 |
— |
— |
[61] |
|
PVA composite membrane (Deutsche Carbone AG/GFTa) |
80 |
0.68 |
100 |
— |
— |
[61] |
|
PVA composite membrane (PERVAP 2201, Sulzer Chemtech) |
60 |
0.1 |
100 |
— |
— |
[62] |
|
PVA on ceramic support |
70 |
1.25 |
35 |
0.5 |
0.58E-12 |
[63] |
|
PVA, 95% hydrolyzed |
70 |
0.086 |
88 |
30 |
2.6E-12 |
[64] |
|
PVA, 99% hydrolyzed |
50 |
0.20 |
50 |
20 |
9.2E-12 |
[65] |
|
PVA blended with sodium alginate on ultrafiltration support |
45 |
0.40 |
250 |
1.8 |
2.5E-12 |
[66] |
|
Table 15.5 Performance of PVA-based membranes reported in the literature at 10 wt% water in feed (the values of some parameters were estimated by interpolation and/or calculated from other reported parameters). |
|
Dehydration to Fuel Grade Ethanol 497 |
fermentation broth was investigated without using the traditional distillation step. They postulated that this type of single-step operation can save energy and lower the production cost in the whole cellulosic ethanol process. In these experiments, pervaporation experiments were performed using a commercially available PDMS (polydimethylsilox — ane) membrane obtained from Pervatech BV (Enter, the Netherlands) using fermented barley straw and willow wood hydrolyzates [67]. Pervaporation was carried out with three different lignocellulosic fermentation broths. The researchers noted that fermentation broths reduced the membrane performance by 17-20% as compared to a base case containing only 3 wt% ethanol in water. The membrane fouling caused by these fermentation broths was irreversible. Solutions containing model lignocellulosic components were also tested during pervaporation at the same conditions. A total flux decrease of 12-15% compared to the base case was observed for each component except for furfural. Catechol was found to be the most fouling component, whereas furfural permeated through the membrane and increased the total flux. Furthermore, Gaykawad and coworkers reported that membrane selectivity increased in the presence of fermentation broth but remained unchanged for all selected components [67].