Generation of Transportation Fuel from Solid Municipal Waste Plastics
Moinuddin Sarker, PhD, MCIC
Natural State Research, Inc.,
37 Brown House Road (2nd Floor),
Stamford, CT-06902, USA
E-mail: [email protected]
ABSTRACT
Transportation fuels derived from imported fossil
fuels are subjected to the price fluctuations of the
global marketplace, and constitute a major expense
in the operation of a vehicle. Emissions from the
evaporation and combustion of these fuels
contribute to a range of environmental and health
problems, causing poor air quality and emitting
greenhouse gases that contribute to global warming.
Alternative fuels created from domestic sources
have been proposed as a solution to these problems,
and many fuels are being developed based on
biomass and other renewable sources. Natural State
Research, Inc. proposes a different alternative
hydrocarbon fuel which is produced from abundant
waste plastic materials. This fuel burns more
efficiently and cleaner than commercial gasoline
and diesel. The process exists to efficiently convert
waste plastic into a reliable low cost source of fuel.
Keywords: waste plastic, hydrocarbon fuel,
transportation fuel, thermal cracking, gas
chromatography, differential scanning calorimetry.
INTRODUCTION
In the United States and in most part of the globe,
transportation fuels are predominantly derived from
imported fossil fuel, which creates an economic and
political dependence on foreign supplies. In recent
period, gasoline and diesel have been subject to
large price swings that strongly affect regional
economic and transportation planning and
budgeting. Economic, political, and environmental
pressures provide the motivation to reduce the use
of conventional transportation fuels and a growth in
the interest for alternate sources to these
conventional transportation fuels.
In urban areas in the United States and around the
world, vehicle emissions are the largest single
source of air pollution and greenhouse gases.
Emissions from gasoline cars include unburned
hydrocarbons, which are responsible for groundlevel ozone and smog; nitrogen oxides (NOx),
which contribute to ozone and acid rain; carbon
monoxide (CO), a toxic byproduct of incomplete
combustion and a health hazard; sulfur dioxide
(SO2), which contributes to acid rain; and carbon
dioxide (CO2), a greenhouse gas that contributes to
global warming.
The exhaust from gasoline
vehicles or from evaporative emissions include
many other harmful compounds, including benzene,
toluene, xylene, styrene, 1,3-butadiene, aldehydes,
ketones, phenols, halogenated hydrocarbons, and
trace metals.
According to a recent study, United States
consumes ~20.7 million barrels of fuel everyday
[1]. With this high level of consumption, the non
renewable fossil fuel sources will be depleted in the
near future. In order to preserve these nonrenewable sources, many nations and countries
around the world are focusing a lot of research on
finding an alternate renewable source to the non
renewable fossil fuel.
Alternative fuels developed from a reliable
domestic source have the potential to overcome
many of these economic / environmental problems
and help us preserve our non renewable fossil fuel
source, by providing a steady, low cost source of
fuel, by providing local employment in energy
production, and by providing fuel types that are
cleaner and produce fewer harmful emissions. Some
of the major alternative fuel research have been
focused on biomass for example, creating cellulosic
ethanol from non-edible biomass sources. However,
biomass energy requires large amount of arable land
to be devoted to the cultivation of plant sources.
There are also strong benefits in deriving alternative
fuels from waste plastic materials because plastics
are predominantly manufactured from petroleum
products. Waste plastic is abundant and its disposal
creates large problems for the environment. Plastic
does not break down in landfills causing lands to be
contaminated, it also causes severe problems in city
water ways, marine ocean life and natural ground
water sources. Plastics are not easily recycled, and it
degrades in quality during the recycling process.
However, chemical processes such as pyrolysis and
de-polymerization can be used to safely convert
plastics into hydrocarbon fuels that can be used for
transportation [2-4]. The United States produces 30
million tons of waste plastic per year, and ~300
million barrels of fuel can be obtained, using a
factor of one ton of waste plastics yielding 10
barrels of fuel using the process described in this
manuscript.
Natural State Research, Inc. (NSR) has developed a
different alternative hydrocarbon fuel which is
produced from abundant solid waste plastic
materials.
The NSR fuel contains additional
hydrocarbons in the range of C3-C27 as compared
with commercial gasoline with an octane rating of
87 (gasoline-87) in the hydrocarbon range C4-C9.
The conversion process of converting waste plastic
materials to liquid hydrocarbon fuel has been
successfully demonstrated in a laboratory scale.
The advantages of NSR’s technique are its
simplicity, which would allow municipalities to
construct local fuel production plants; its ability to
handle many plastic types; and its ability to produce
a variety of fuel types for different transportation
needs, e.g., for gasoline, diesel, or aviation fuel
engines.
PROCESS DESCRIPTION
The process involves heating the plastic to form
liquid slurry (thermal liquefaction in the range
370°-420°C), distilling the slurry in with or without
cracking catalyst, condensing the distillate to
recover the liquid hydrocarbon fuel, and routing the
remaining slurry residue back into fresh slurry to
undergo another distillation/condensation process.
No additional chemicals are used in the thermal
liquefaction phase. The fuel is filtered using a
commercial fuel filter that operates using
coalescence and centrifugal force.
Small-scale conversion tests have been performed
with the simplified process shown in Figure 1, on
various waste plastic types: High density
polyethylene (HDPE, code 2), low density
polyethylene (LDPE, code 4), polypropylene (PP,
code 5) and polystyrene (PS, code 6). These plastic
types were investigated singly and in combination
with other plastic types. In the laboratory scale
process, the weight of a single batch of input plastic
for the fuel production process ranges from 300
grams to 3 kilograms. The plastics are collected,
optionally sorted, cleaned of contaminants, and cut
or divided into small pieces prior to the thermal
liquefaction process. It should be noted here that
NSR process does not exclude the use of random
mixtures of plastic types.
Preliminary tests on the produced NSR fuel have
shown that it is a mixture of various hydrocarbons
having a range of carbon chain lengths from C3 to
C27. The produced NSR fuel density is typically
0.776 g./ml which is slightly higher than the density
of commercial gasoline (0.711 – 0.770 g./ml) and
lower than the density for kerosene (0.820 g./ml).
The fuel is highly flammable and volatile, contains
high heat capacity, and has been shown to
successfully run a gas-powered generator, Diesel
generator, a gas-powered lawn mower and an
automobile.
The filtered fuel obtained goes through another
thermal distillation process. Early 40% of the
distillate was collected. It was named “NSR double
condensed fuel 1st collection” or “NSR-1”; another
50% was collected and named “NSR Double
condensed fuel 2nd collection” or “NSR-2” and the
last 10% remains in the double distillation boiling
flask and it is termed “Residual Fuel” or “NSR-3”.
To obtain further refined grade, NSR is working on
using fractional distillation to separate the mixed
waste plastic to individual category fuels. The fuels
that will be obtained are; (a) Gasoline, (b) Naphtha,
(c) Aviation / Jet fuel (Kerosene), (d) Diesel fuel,
and (e) Fuel oil.
Figure 2: Chromatogram of NSR Double
condensed 1st collection.
2
4
6
Intensity (a.u)
2
10. 2,4-Dimethyl-1-Heptene (C9H18)
11. Ethyl-Benzene (C8H10)
12. Styrene (C8H8)
13. 1-Methyl-Benzene (C9H12)
14. 1-Decene (C10H20)
15. 3,3-Dimethyl-Octane (C10H22)
16. 3,7-Dimethyl-1-Octene (C10H20)
17. Undecane (C11H24)
18. Dodecane (C12H26)
7
5
NSR Double Condensed 1st Collection
9
14
6
13
2
4
6
8
15 16 17
10
18
12
14
16
18
20
22
Retention Time In Minutes
24
26
28
24
13
25
9
11
8
14
17
26
21
27
19
16
10
28
29
30
12
14
16
18
20
22
24
26
28
30
6
14
12. Heptane C7H16
13. Methyl-Cyclohexane C7H14
14. Toluene C7H8
15. Octane C8H18
16. Ethyl Benzene C8H10
17. P-Xylene C8H10
18. P-Xylene C8H10
19. 1-Ethyl-4-Methyl-Benzene C9H12
20. 1,2,4-Trimethyl-Benzene C9H12
7
4
2
11
9
8 10
5
1
Commercial Gasoline-87
17
12 13
4
16
6
20
18
19
8
10
12
14
16
18
20
22
24
26
28
30
Figure 4: Chromatogram of Commercial gasoline
87.
12
11
1 3
23
12
Retention Time in Minutes
4
8
18
15
1. Butane C4H10
2. Ethylalcohol C2H6 O
3. 2-Methyl-Butane C5H12
4. Pentane C5H12
5. Cyclopropene C5H10
6. 2-Methyl-Pentane C6H14
7. Hexane C6H14
8. Methyl-Cyclopentane C6H12
9. 2-Methyl-Hexane C7H16
10. 3-Methyl-Hexane C7H18
11. 1,3-Dimethyl-Cyclopentane C7H14
3
2
1. 2-Methyl-1-Propene (C4H8)
2. Pentane (C5H12)
3. 2-Methyl-Pentane (C6H14)
4. 2-Methyl-1-Pentene (C7H14)
5. Hexane (C6H14)
6. 2,4-Dimethyl-1-Pentene (C7H14)
7. 3,5-Dimethyl-2-Hexene (C8H16)
8. Toluene (C7H8)
9. Octane (C8H18)
10
NSR Double Condesned
2nd Collection
Figure 3: Chromatogram NSR Doubled condensed
2nd Collection.
15
10
8
22
20
Retention Time in Minutes
Intensity (a.u)
Tests have been performed to investigate the
composition of the produced fuel. Figure 2-6 show
gas chromatograms of five different fuels
illustrating the differences in carbon chain length:
(2) NSR double condensed fuel 1st collection (
NSR–1), (3) NSR double condensed fuel 2nd
collection ( NSR–2), (4) commercial gasoline
(octane # 87), (5) Aviation fuel, and (6) commercial
diesel. The NSR 1st collection fuel contains
hydrocarbon groups ranging from (C4-C12)
compared with commercial gasoline with (C4-C9).
Gas chromatography (GC) tests, Figures (2) and (3),
show peak intensity distribution throughout the
range of hydrocarbon groups C3-C27, with
retention times ranging from 2 min to 27 min. On
the other hand GC tests for commercial fuels show
narrow ranges of hydrocarbon groups – Figure (4)
for commercial gasoline (87) contains C4-C9;
Figure (5) for commercial aviation fuel contains
C9-C19; Figure (6) for commercial diesel contains
C7-C27.
Intensity (a.u)
FUEL CHARACTERIZATION
1. 2,4-Dimethyl-1-Heptene (C9H18)
2. Styrene (C8H8)
3. Decane (C10H22)
4. 2,4-Dimethyl-1-Heptanol (C9H20 O)
5. 1,4-Dimethyl-Cyclooctane (C10H20)
6. Undecane (C11 H24)
7. 3,7,11-Trimethyl-1-Decanol (C15H32 O)
8. 3-Dodecene (C12H24)
9. Dodecane (C12H26)
10. 2,3,5,8-Tetramethyl-Decane (C14H30)
11. 2-Tridecene (C13H26)
12. 3-Octadecene (C18H36)
13. 2-Isopropyl-5-Methyl-1-Heptanol (C11H24 O)
14. 1-Tetradecene (C14H30)
15. Tetradecane (C14H30)
16. 2,3,5,8-Tetramethyl-Decane (C14H30)
17. 1-Tridecene (C13H26)
18. Hexadecane (C16H34)
19. 3,7,11-Trimethyl-1-Dodecanol (C15H32 O)
20. Hexadecane (C16H34)
21. 1-Nonadecene (C19H38)
22. Heptadecane (C17H36)
5
23. Octadecane (C18H38)
6
24. Nonadecane (C19H40)
25. Eicosane (C20H42)
26. Heniecosane (C21H44)
27. Heniecosane (C21H44)
3
29. Eicosane (C20H42)
30. Heptacosane (C27H56)
7
4
1 2
30
8
5
1. 2-Methyl-Octane (C9H20)
2. Nonane (C9H20)
3. 2,6-Dimethyl-Octane (C10H22)
4. 4-Methyl-Nonane (C10H22)
5. Decane (C10H22)
6. 4-Methyl-Decane (C11H24)
7. 1,3-Diethyl-Benzene (C10H14)
8. Undecane (C11H24)
9. 3-Methyl-Undecane (C12H26)
10. Dodecane (C12H26)
11. 2,6-Dimethyl-Undecane (C13H28)
12. 2,6-Dimethyl-Heptadecane (C19H40)
13. Tridecane (C13H28)
14. 2,6,10-Trimethyl-Dodecane (C15H32)
15. Tetradecane (C14H30)
16. Hexadecane (C16H34)
17. Hexadecane (C16H34)
18. Nonadecane (C19H40)
10
Intensity (a.u)
13
15
2
16
11
6 7
9
4
Commercial
Aviation Fuel
12
14
17
3
1
patterns of the commercial diesel. The
hydrocarbons distribution of NSR-2 fuel is observed
up to the retention time of 27 minutes which is the
same as commercial diesel.
18
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Retention Time In Minutes
Figure 5: Chromatogram of Commercial Aviation
Fuel.
Intensity (a.u)
1. Methyl-Cyclohexane (C7H14)
2. Octane (C8H18)
3. Ethyl-Cyclohexane (C8H16)
4. Ethyl-Benzene (C8H10)
5. P-Xylene (C8H10)
6. Nonane (C9H20)
7. 3-Methyl-1-Ethyl-Benzene (C9H12)
8. 1,3,5-Trimethyl-Benzene (C9H12)
9. 2-Propyl-1-Methyl-Benzene (C10H14)
10. Undecane (C11H24)
11. Dodecane (C12H26)
8
12. 6-Methyl-1,2,3,4-TetraHydroNapthalene (C10H12)
13. Tridecane (C13H28)
14. 2,6-dimethyl-1,2,3,4-TetraHydroNapthalene (C12H12)
15. Tetradecane (C14H30)
16. 2,6,10-TrimethylTetradecane (C17H36)
17. Pentadecane (C15H32)
18. Hexadecane (C16H34)
19. Nonadecane (C19H40)
20. Octadecane (C18H38)
21. Nonadecane (C19H40)
22. Eicosane (C20H42)
23. Heniecosane (C21H44)
24. Heniecosane (C21H44)
25. Nonadecane (C19H40)
26. Nonadecane (C19H40)
27. Heptacosane (C27H56)
17
11
18
15
19
20
10
13
A comparative analysis, using a differential
scanning calorimeter, shows that NSR fuel has a
higher boiling point (>94 °C) than that of the
commercial gasoline-87 (68.14 °C). These values
indicate that NSR fuel contains more long chain
hydrocarbon compounds than those in commercial
gasoline-87, and these chains can be shortened
during the double condensation process. As shown
in Figure 3, NSR’s double condensed filtered fuel
1st and 2nd collections, respectively, show the onset
of the boiling points to 94.52 °C and 194.52 °C.
Both GC and DSC data indicate that NSR fuel
contains a higher percentage of volatile
hydrocarbon compounds.
21
22
23
12
14
16
24
9
7
5
4
1 2
25
6
26
3
27
Commercial Diesel
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Retention Time In Minutes
Figure 6: Chromatogram of Commercial Diesel.
Commercial gasoline (87) chromatogram (Figure 4)
shows an even peak intensity distribution up to the
retention time of 9 min. For longer retention times,
the peak intensities are decreased.
Thus,
commercial gasoline has a higher intensity of
hydrocarbon compounds (C4 to C9) at the lower
retention time, and fewer hydrocarbon compounds
with longer carbon chain (C10 to C20) or none in
the retention time range of 9 to 27 min. It is also
observed that commercial gasoline-87 has a lower
intensity of straight chain hydrocarbon compounds
when compared with NSR fuel.
Commercial diesel chromatogram (Figure 6) shows
a peak intensity distribution up to the retention time
of 27 minutes. The indicates that commercial diesel
contains high molecular weight hydrocarbon
compounds (C7 to C27). In a comparison with NSR
fuels, the double condensed 2nd collection fuel
“NSR-2” matches the retention time and the peaks
Figure 7. Differential scanning calorimeter (DSC)
curves of several fuels illustrating different onsets
of the boiling points.
Experiments with 2 ml samples showed that NSR
fuel required 4.48 minutes to burn, while
commercial gasoline-87 required 1.72 minutes to
burn. This indicates that NSR fuel should yield
more energy than gasoline-87 because of NSR
fuel’s longer burning time. Gasoline-87 has higher
concentrations of benzene, toluene, styrene, xylene,
and naphthalene compounds compared with the
NSR fuel. Furthermore, unlike gasoline-87, NSR
fuel contains no sulfur, methyl trer-butyl ether
(MTBE), tret amyl-methyl ether (TAME) and (Diisopropyl Ether (DIPE). These emission test
parameters are obtained from EPA standard test
result conducted at intertak laboratory in New
Jersey.
AUTOMOBILE TEST DRIVING RESULT
We used NSR fuel (double condensed 1st collection)
and commercial gasoline-87 for automobile test
driving. A 1984 Oldsmobile vehicle (V-8 powered
engine) was used for the test driving and one gallon
of fuel was used for both cases after complete
drainage of the pre-existing fuel in the fuel tank.
The test driving was done on a rural highway with
an average speed of 55 mph.
Based on the preliminary automobile test driving,
the NSR fuel has offered a competitive advantage in
mileage over the commercial gasoline-87. NSR
fuel showed better mileage performance of 18 miles
per gallon (mpg) compared to 15 miles per gallon
(mpg) with commercial gasoline-87. That’s an extra
3 miles more output from the NSR fuel. A diagram
is presented to blow for visual understanding.
V8 Engine Car Run Test Result in Miles
18.5
NSR 1st
NSR 1st Collection Fuel
Commercial Gasoline 87
Collection Fuel,
(18 Miles)
18
17.5
17
16.5
16
15.5
Commercial Gasoline 87 ,
(15 Miles)
15
14.5
14
13.5
1
Figure 8: V8 Engine Car Run Test Result using
NSR -1st Collection Fuel and Commercial gasoline
87
It is expected that NSR double condensed fuel will
show even higher performance with more fuel
efficient car such as V-4 engine and hybrid
vehicles. Additional driving tests are in progress.
While performing the above mentioned automobile
test driving, we have also checked the emission
from the fuel burning using ENMET MX 2100
emission tester positioned 1 foot from the car
exhaust. The test results were found to be similar
(see Table 1).
Table 1. Emission results (1 foot from car exhaust)
for comparison between NSR double condensed
filtered fuel (1st collection) and commercial
gasoline-87.
Emission Gas
CO
H2S
O2
CH4
NSR Double
Condensed 1st
Collection Fuel
1200
-3
21.0
5
Commercial
Gasoline 87
1200
-2
16.8
0
CONCLUSION
A simple thermal process for de-polymerizing waste
plastic to useful transportation fuel has been
developed and further refined using a laboratory
scale double condensation process and fractional
distillation process. Characterization studies by GC
and GC-MS indicate the de-polymerization product
is essentially all straight chain hydrocarbons when
linear thermoplastic polymers are used as the feed.
Both GC and DSC studies indicate the product
includes hydrocarbons ranging from C3 to C27, a
range that includes commercial gasoline-87 and
diesel fuel. Automobile test driving with double
condensed filtered NSR fuel shows competitive
advantage in mileage over commercial gasoline-87,
while using a low fuel efficient engine.
A
calculated 16.7% higher mpg is observed with NSR
fuel when compared to gasoline-87. Further testing
is in progress with high fuel efficient engine.
ACKNOWLEDGMENTS
The author acknowledges the valuable contributions
made by NSR science team, Dr. Richard Parnas and
Dr. Sabir Majumder during the preparation of this
manuscript.
REFERENCES
1.
U.S. Energy information Administration, world
supply and consumption of petroleum products,
Wikipedia,
http://en.wikipedia.org./wiki/Petroleum
2.
Y. Uemichi, Development of a catalytic
cracking process for converting waste plastics to
petrochemicals, J. Mat. Cycles Waste
Manage.,5(2), 89-93, 2003.
3.
A. Marcilla, A. Gómez-Siurana and F. Valdés,
Catalytic cracking of low-density polyethylene
over H-Beta and HZSM-5 zeolites: Influence of
the external surface. Kinetic model, Polym.
Degrad. and Stability, 92(2), 197-204, 2007.
4.
G. Manos, “Catalytic Degradation of Plastic Waste to
Fuel Over Microporous Materials” Chapter 7 in
Recycling of Waste Plastics: Pyrolysis and Related
Feedstock Recycling Techniques, (Eds: J. Scheirs,
W. Kaminsky), J. Wiley, 193-208, 2006.
CONTACT:
Moinuddin Sarker, PhD, MCIC
Vice President (R&D)
Natural State Research Inc.
37 Brown House Road, (2nd Floor)
Stamford, CT, 06902, USA
Phone: 203-406-0675
Fax: 203-406-9852
Email: [email protected]