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Dr. Philip Steele
Professor
Mississippi State University
Production of Multiple Fuel Types from
Bio-oil
Philip H. Steele
Venkata K Penmetsa
Satish K Tanneru
Forest Products Department
Mississippi State University
Bio-oil properties:
40-50% oxygen content is the primary factor causing the
negative properties of bio-oil:
• High acidity
• Aging problem (polymerization)
• Immiscibility with petroleum-derived fuels
• Pungent odor
• Low energy density (35 – 40% petroleum fuels)
Olefination of bio-oil requires reaction of an
olefin (10%) with the bio-oil; a relatively high
HHV boiler fuel is produced (fuel 1):
• Olefination requires alcohol addition at a
relatively low percentage (20%)
• An aqueous fraction is produced that reduces
water content of the fuel after being
separated from the organic fraction
Olefination reaction scheme:
• The reaction predominantly produces ethers
and esters; a small percentage of water (<5%)
is converted to alcohol
Mass balance of olefination process:
Olefinated bio-oil
Olefination fuel properties:
Raw Bio-oil
Boiler Fuel
Acid value
98.0
19.2
HHV, MJ/kg
16.1
34.0
Water, %
30.6
1.7
C, %
36.2
71.1
H, %
7.8
10.0
N, %
0.03
0.1
O, %
55.9
18.8
Product testing:
• A highly combustible boiler fuel is produced
by olefination as the test below indicates:
Esterification to bio-diesel (fuel 2):
Catalyst
•
R-COOH + R’-OH
R-COOR’+ H2O
•
Complete conversion of the acids, aldehydes, and
ketones require 10-14 moles of alcohol per kg of
bio-oil; not economically viable
•
The high water content (20-30%) in raw bio-oils
plus water from the esterification reaction create
equilibrium limitations
Esterification to bio-diesel (fuel 2):
•
Our research has focused on reducing the amount of
alcohol to accomplish the reaction and to provide
adequate stability such that equilibrium reaction
reversal due to presence of water was slowed
•
Aqueous fraction for 20% alcohol is about 20% with
about 55% boiler fuel yield
Esterification to bio-diesel (fuel 2, early
results):
Raw Bio-oil
Bio-diesel
ASTM D 6751
bio-diesel
Acid value
98.0
16.7
0.5
HHV, MJ/kg
16.1
36.5
36
Water, %
30.6
5.3
0.05
C,%
36.2
78.2
77
H,%
7.8
9.7
12
N,%
0.03
0.4
0.05
O,%
56.0
11.7
11
Bio-oil hydroprocessing to hydrocarbons:
Bio-oil
Using 100%
hydrogen
Packed bed reactor
*Provisional patent filed
Low hydrogen* (<50%)
Continuous stirred
tank reactor
Both packed bed reactor hydrogen
processing and low hydrogen autoclave HT
a high-quality hydrocarbon mix is produced:
Removal of
oxygenated
compounds
100%Hydrogen/
Low Hydrogen*
Hydrocarbons
Water
Bio-oil
*Provisional patent filed
Upgraded bio-oil
Packed bed reactor plugging and catalyst
deactivation occurs quickly:
Hydrotreating plugging
Catalyst deactivation
Elliott (2007)
Coke plugging
48 h
Elliott (2009)
Coke plugging
100 h
Elliott (2010)
Coke plugging
10 – 100 h
Elliott (2012)
Coke plugging
90 – 91.5 h
MSU experiments
(2012)
Coke plugging
28 h and improving
MSU continuous packed bed reactor:
Hydroprocessing with the MSU
continuous packed bed reactor (fuel 3):
Raw bio-oil
MSU hydrocarbons
Acid value
98.0
13.4
HHV, MJ/kg
16.1
41.3
Water, %
30.6
1.9
0.3
38
42
Yield %
*Elliott et al
2012
C,%
36.2
79.0
84.0
H,%
7.8
10.6
10.4
N,%
0.03
0
0.1
O,%
56.0
10.4
2.1
*Energy and Fuels 26(6):3891-3896. doi:10.1021/ef3004587
Hydrotreating bio-oil with low hydrogen:
• MSU has developed a hydroprocessing
technique (provisional patent filed) utilizing
low hydrogen rather than 100% hydrogen for
the hydrotreating stage
• This can allow a low hydrogen hydrotreating
closer to the resource rather than at a
methane cracking facility; the stabilized bio-oil
can then be transported and stored without
aging
1st stage hydrotreating comparing 100%
hydrogen and low hydrogen results (fuel 4):
Raw Bio-oil
Hydrogen
Low Hydrogen
Acid value
98.0
55.5
51.6
HHV, MJ/kg
16.1
34.7
36.5
Water, %
30.6
3.1
2.7
C,%
36.2
73.7
76.4
H,%
7.8
9.7
9.1
N,%
0.03
0
0
O,%
56.0
15.2
14.0
Comparison of diesel fuel with hydrocarbon mix
produced with low hydrogen HT followed by 100%
hydrogen HC and comparison with diesel fuel (fuel
4, early results):
Raw Bio-oil
HC bio-oil (H2)
Diesel
Acid value
98.0
< 0.1
0
HHV, MJ/kg
16.1
43.0
45.8
Water, %
30.6
0.5
0
C,%
36.2
86.2
85.1
H,%
7.8
12.1
12.2
N,%
0.03
0.01
0
O,%
56.0
1.5
0
Simulated distillation of hydrocarbon mix
produced by low hydrogen HT followed by
100% hydrogen HC:
Gasoline, 55%
Summary:
• MSU has explored both traditional and new
approaches to upgrading bio-oil
• Olefination is a novel method of producing a boiler
fuel (fuel 1) with low water content and a relatively
high HHV of 34 MJ/kg (patent pending)
• Esterification of bio-oil to biodiesel produces a high
energy (36.5 MJ/kg) boiler fuel (fuel 2) with the
potential to produce biodiesel meeting ASTM
transportation fuel quality
• MSU has progressed to production of mixed
hydrocarbons with packed bed technology (fuel 3);
improvement is ongoing
Summary:
• MSU has pioneered the utilization of low hydrogen
in the hydrotreating stage to conserve hydrogen.
The resulting mixed hydrocarbons (fuel 4) contain
the petroleum molecular weight equivalents of 55%
gasoline, 30% jet fuel and 15% diesel
Acknolwedgement:
• This research is based upon work funded
through the Sustainable Energy Research
Center at Mississippi State University and is
supported by the Department of Energy under
Award Number DE-FG3606GO86025.
Production of Multiple Fuel Types from
Bio-oil
Philip H. Steele
Venkata K Penmetsa
Satish K Tanneru
Forest Products Department
Mississippi State University
Dr. Philip Steele
Professor
Mississippi State University