Environmental Engineering Reference
In-Depth Information
Table 8.2
Comparison of oil yield vs required land for different biodiesel feedstocks in the US
[74, 75]
Required land (M ha)
a
Crop
Oil yield (L/ha)
Microalgae
b
136,900
2
Microalgae
c
58,700
4.5
Oil palm
5950
45
Jatropha
1,892
140
Canola
1190
223
Soybean
446
594
Corn
172
1540
a
To meet 50% of all US current transport consumption;
b
70% (w/w) oil yield in biomass;
c
30% (w/w) oil yield in biomass.
Table 8.3
Oil production (oil content and yield) of different microorganisms grown on various
carbon sources [79, 80]
Biomass
(g/L)
Oil content
(%)
Oil yield
(g/L)
Microorganism
Carbon source
References
Trichosporon
fermentans
Molasses
36.4
35.3
12.8
[78]
Lipomyces
starkeyi
Sewage sludge
9.4
68.0
6.4
[79]
Mortierella
isabellina
Starch
10.4
36.0
3.7
[80]
Pectin
8.4
24.0
2.0
Cunningamella
echinilata
Starch
13.5
28.0
3.8
Pectin
4.1
10.0
0.4
In general, the cultivation of such microorganisms is not dependent on seasons
or climate. They can also be easily grown on a variety of inexpensive substrates
including waste residues from agriculture and industry [79], providing they have
the nutrients needed for the microorganisms.
8.2.2.2 Biofuels Produced by Thermo-(Chemical) Conversion
Biofuels included under this headline are also prepared from various non-edible
biomass feedstocks. Thermo-chemical conversion pathways include processes such
as gasification and pyrolysis (Fig. 8.8) [81-83].
Biofuels from Gasification
The process involves the partial combustion of the feedstock to produce syngas
(a mixture of carbon monoxide (CO) and hydrogen (H
2
) denoted as bio-Synthetic
Natural Gas, bio-SNG) via conventional or alternative gasification processes. Then,
bio-SNG is subsequently transformed into liquid hydrocarbons (mostly diesel and
kerosene-type fuels) and/or gases via different processes, leading to a variety of
biofuels that will be outlined. Such prospective liquid/gas biofuels for transport
