Int. J. Pure Appl. Sci. Technol., 11(2) (2012), pp. 36-44
International Journal of Pure and Applied Sciences and Technology
ISSN 2229 - 6107
Available online at www.ijopaasat.in
Research Paper
Thermal Conversion of Polymer Wastes (LDPE) into
Hydrocarbon Diesel Fuel without Cracking Catalysts
Moinuddin Sarker1,*, Mohammad Mamunor Rashid2 and Muhammad Sadikur Rahman3
1, 2, 3
Natural State Research, Inc. Department of Research and Development, 37 Brown House Road
(2nd Floor), Stamford, CT 06902, USA
* Corresponding author, e-mail: ([email protected])
(Received: 30-6-12; Accepted: 16-7-12)
Abstract: Thermal conversion process was applies with low density
polyethylene (LDPE) waste plastic without using any kind of cracking
catalyst, and two types of temperature was use for diesel grade fuel
collection. Experimental purposed LDPE waste plastic was use 100% by
weight and initial feed LDPE sample was 800 gm. In this experiment was
perform laboratory small scale under Labconco fume hood without vacuum in
presence of oxygen and fully closed system. LDPE waste plastic to diesel
grade fuel fractional distillation collection temperature was 260-290 ºC and
LDPE waste plastic to direct liquefaction process temperature was 120-430
ºC. Produced fuel was analysis by Perkin Elmer GC/MS, FT-IR and DSC.
Fuel density is 0.80 g/ml. By using GC/MS analysis result showed
hydrocarbon compounds range is C3 to C28, FT-IR analysis result indicate
that produce fuel has functional group such as H Bonded NH, C-CH3, CH3, CH=CH2, -CH=CH-(cis), C=CH2 etc. DSC analysis result indicates that fuel
enthalpy delta H value 18116.1385 J/g. Produce fuel could be use as
combustion engines or feed stock for refinery process.
Keywords: Thermal conversion, waste plastic, fuel, hydrocarbon, diesel,
conversion, GC/MS.
1. Introduction:
The amount of plastic wastes is growing year after year, and the fraction of plastics in municipal solid
wastes (MSW) and in refuse-derived fuels (RDF) is progressively increasing. Pyrolysis and
gasification processes appear to be promising routes for the upgrading of solid wastes to more usable
and energy dense materials such as gas fuel and/or fuel oil or to high value feed stocks for the
chemical industry. Therefore the characterization of the pyrolysis behavior of plastic wastes is of
Int. J. Pure Appl. Sci. Technol., 11(2) (2012), 36-44.
37
interest in the optimization of pyrolysis processes for the recovery of energy rich or valuable product
fractions. Furthermore, a pyrolysis step is always present in the initial stages of gasification and of
combustion. Pyrolysis and gasification processes yield three different product fractions: a solid
fraction (char), a condensable fraction (tar), and a gaseous fraction. The operating conditions (mainly
heating rate and temperature) and the starting materials influence the composition and the relative
amount of the three product fractions. Moreover the final product yields from pyrolysis and
gasification processes are strongly influenced by secondary gas-phase reactions occurring to the
primary products released during solid degradation [1].
The thermal pyrolysis of plastic wastes produces a broad distribution of hydrocarbons, from methane
to waxy products. This process takes place at high temperatures. The gaseous compounds generated
can be burned out to provide the process heat requirements, but the overall yield of valuable gasoline
range hydrocarbons is poor, so that the pyrolysis process as a means for feedstock recycling of the
plastic waste stream is rarely practiced on an industrial scale at present [2, 3]. In contrast, thermal
cracking at low temperatures is usually aimed at the production of waxy oil fractions, which may be
used in industrial units for steam cracking and in fluid catalytic cracking units [4]. An alternative to
improve gasoline yield from plastics pyrolysis is to introduce suitable catalysts. High conversions and
interesting product distributions are obtained when plastics are cracked over zeolites [5-7]. Moreover
the catalytic cracking of polymers has proven itself to be a very versatile process, since a variety of
products can be obtained depending on the catalyst, [8-11] the polymer, [12, 13] the reactor type, [14,
15] and the experimental conditions used, [16, 17, 18] among other variables. Most published studies
concentrate on discussing the results obtained from the analysis of the global composition of the
products generated. However, studies regarding the evaluation of the composition of the products
generated in the degradation process at different conversion levels are scarcely available. This type of
study can provide very interesting information regarding the reaction sequences during the course of
the degradation process or the deactivation suffered by the catalysts.
2. Materials and Process Description:
LDPE waste plastic was collected from local restaurant and LDPE waste plastic was transparent color
food /soup container cover. Collected all LDPE waste plastic food container cover washed with liquid
soap and dry into room atmosphere. LDPE waste plastic food container cover was hard shape and it
was grinded by grinder machine for fit into reactor chamber. After grinder finished LDPE waste
plastic put into reactor chamber and placed into reactor inside with LDPE waste plastic as initial feed.
Reactor cover was covered with screw and screw tighten was properly prevent gas or any vapor loss.
In this experimental process was setup small scale under laboratory Labconco fume hood without any
vacuums system and set up was fully closed system but in presence of oxygen.
Figure 1: LDPE waste plastic to diesel grade fuel production process
Int. J. Pure Appl. Sci. Technol., 11(2) (2012), 36-44.
38
In this experiment performed without catalyst or any kind of chemicals. Experimental process setup
explain in figure 1 from LDPE waste plastic to diesel grade fuel production such as 1 = LDPE waste
plastic, 2= Steel reactor, 3 = Fractional distillation column, 4= 1st fractional temperature, 5= 2nd
fractional temperature, 6=3rd fractional temperature, 7= 4th fractional temperature, 8= 5th fractional
temperature, 9= light gas cleaning system with alkali solution, 10= 1st fractional fuel collection tank,
11=2nd fractional fuel collection tank, 12=3rd fractional fuel collection tank, 13=4th fractional fuel
collection tank, 14 = 5th fractional fuel collection tank, 15 = Small pump for gas transfer into Teflon
Bag, 16 = Teflon bag for light gas storage. For experimental purposes initial feed was use only 800
gm by weight. In this experiment main goal was LDPE waste plastic to liquefaction then fractionation
process to diesel grade fuel collection. For LDPE waste plastic to diesel grade fuel production
purposed two type temperature was used one for liquefaction temperature and another for
fractionation temperature profile. LDPE waste plastic to liquefaction temperature range was 120-430
ºC and fractional distillation column temperature was 260-290 ºC for diesel grade fuel collection. In
the experiment LDPE plastic melting point 120ºC known temperature for that reason LDPE waste
plastic to diesel grade fuel collection experiment starting temperature was 120 ºC and finished
temperature was 430 ºC. Temperature was increased gradually from 120ºC to up to 430 ºC, then
plastic start to melt, then melted plastic turn into liquid phase when temperature increased, then liquid
phase plastic turn into vapor when temperature profile more than 300 ºC and at the end vapor travel
through fractional distillation column according to their boiling point range wise. Light fraction
boiling point hydrocarbon which boiling point range negative that gas will come out faster and was
not condense and its call light gas or natural gas. Low boiling to high boiling point range hydrocarbon
was collected different by fractional column and diesel grade fractional fuel was collected in the
diagram 13 number collection tank and fractional column number was 7 and temperature range for
diesel grade fuel collection at 260-290 ºC. This process was batch process and light gases were
purified by using alkali solution wash then transferred into Teflon bag using small pump. Light gas is
hydrocarbon mixture such as methane, ethane, propane and butane. Produced diesel grade fuel was
purified after finished whole experiment and separated into container for further analysis. Produced
fuel density was 0.80g/ml. in this experiment mass balance calculation indicate that initial feed 800
gm LDPE waste plastic to diesel grade liquid fuel was 152 gm, rest of other grade fuel was 584 gm,
light gas was from 800 gm initial feed to 32 gm and leftover solid black residue is 32 gm from total
initial feed. In percentage calculation for this experiment from 800 gm LDEP waste plastic to diesel
grade fuel is 19%, other grade fuels is 73%, and light gas is 4% and solid black residue is 4%. Total
experiment run time was 6 hours 45 minutes and input electricity was 7.52 kWh. In put electricity cost
could be reduce by using produced light gas as a heat source when commercialization plant will be
implement.
Intensity (a.u.)
3. Result and Discussion:
0
5
1 0
1 5
2 0
2 5
3 0
R e te n tio n T im e (M )
Figure 2: GC/MS chromatogram of LDPE waste plastic to diesel fuel
3 5
Int. J. Pure Appl. Sci. Technol., 11(2) (2012), 36-44.
39
Table1: GC/MS chromatogram of LDPE waste plastic to diesel fuel compound list
Number
of Peak
1
2
3
Retention
Time
(min)
1.53
1.65
1.91
Trace
Mass
(m/z)
40
43
42
4
5
6
7
8
9
10
11
12
13
14
15
16
1.95
2.53
2.60
3.65
3.77
5.19
5.34
6.92
7.07
8.64
8.79
10.30
10.43
43
41
41
41
43
41
43
41
43
41
43
41
43
17
18
19
11.85
11.98
13.33
41
57
41
20
21
13.45
14.60
43
70
22
14.71
41
23
24
14.82
15.91
71
41
25
16.01
43
26
27
16.12
16.65
57
43
28
16.88
83
29
17.15
70
30
31
17.24
17.35
41
43
Compound
Name
Propane
Butane
Cyclopropane,
ethylPentane
1-Hexene
Hexane
1-Heptene
Heptane
1-Octene
Octane
1-Nonene
Nonane
1-Decene
Decane
1-Undecene
Undecane
1-Dodecene
Dodecane
3-Tridecene,
(E)Tridecane
3-Tetradecene,
(E)3-Tetradecene,
(Z)Tetradecane
E-2Hexadecacen-1ol
1-Pentadecene
Pentadecane
1-Hexadecanol,
2-methyl1-Nonadecanol
2-Methyl-E-7hexadecene
1-Hexadecene
Hexadecane
Compound Molecular
Formula
Weight
C3H8
C4H10
C5H10
44
58
70
C5H12
C6H12
C6H14
C7H14
C7H16
C8H16
C8H18
C9H18
C9H20
C10H20
C10H22
C11H22
C11H24
72
84
86
98
100
112
114
126
128
140
142
154
156
C12H24
C12H26
C13H26
168
170
182
C13H28
C14H28
184
196
C14H28
196
C14H30
C16H32O
198
240
C15H30
210
C15H32
C17H36O
212
256
C19H40O
284
C17H34
238
C16H32
C16H34
224
226
CAS
Number
74-98-6
106-97-8
1191-964
109-66-0
592-41-6
110-54-3
592-76-7
142-82-5
111-66-0
111-65-9
124-11-8
111-84-2
872-05-9
124-18-5
821-95-4
1120-214
112-41-4
112-40-3
4144657-5
629-50-5
4144668-8
4144667-7
629-59-4
N/A
1336061-7
629-62-9
2490-484
1454-848
6418352-4
629-73-2
544-76-3
Int. J. Pure Appl. Sci. Technol., 11(2) (2012), 36-44.
32
33
18.06
18.32
43
41
34
18.40
43
35
36
18.50
19.26
57
57
37
19.51
43
38
39
19.60
20.57
40
41
40
C20H42O
C18H36O
298
268
629-96-9
N/A
C16H30O
238
C17H36
C19H40
240
268
C17H32O
252
33020753-9
629-78-7
6186803-9
N/A
57
43
1-Eicosanol
E-2Octadecadecen1-ol
E-14Hexadecenal
Heptadecane
Heptadecane,
2,3-dimethylE-15Heptadecenal
Octadecane
9-Nonadecene
C18H38
C19H38
254
266
20.65
21.57
71
55
Nonadecane
1-Docosene
C19H40
C22H44
268
308
42
43
21.65
22.53
57
43
C20H42
C21H42
282
294
44
45
46
47
48
49
50
51
22.61
23.51
24.39
25.24
26.06
26.86
29.20
29.97
85
71
43
57
57
57
57
57
Eicosane
10-Heneicosene
(c,t)
Heneicosane
Heneicosane
Heneicosane
Tetracosane
Heneicosane
Octacosane
Octacosane
Heptacosane
C21H44
C21H44
C21H44
C24H50
C21H44
C28H58
C28H58
C27H56
296
296
296
338
296
394
394
380
593-45-3
3103507-1
629-92-5
1599-673
112-95-8
9500811-0
629-94-7
629-94-7
629-94-7
646-31-1
629-94-7
630-02-4
630-02-4
593-49-7
Perkin Elmer GC/MS analysis of LDPE waste plastics to 4th fractional fuel/ diesel fuel (Figure 2 and
Table 1) hydrocarbon compound list is analyzed based on their peak intensity. GC/MS chromatogram
analysis is showing higher concentration level peak intensity. This fuel fractional temperature is 340365 ºC. This fuel is similar to fuel oil category. Chromatogram analysis starting compound is Propane
(C3H8) at retention time is 1.53 minutes. From data table we saw all hydrocarbon compounds are
straight chain hydrocarbon compounds and some are branch chain hydrocarbon compounds are as
well. From the fuel we found alkane group and alkene group compound. Long chain hydrocarbon
compound showing at retention time 29.97 minutes and compound is Heptacosane (C27H56) and
molecular weight is 380. In the fuel all hydrocarbon compounds contains heavy hydrocarbon and their
derivatives as well as hydrocarbon range is C5-C28.In the detail analysis prospects maximum
compounds are mention from the analysis result index. Such as in detail analysis according to the
retention 1.65 and trace mass 43, compound is Butane (C4H10), retention time 1.91 and trace mass
42, compound is Cyclopropane, ethyl ( C5H10), retention time 2.60 and trace mass 41, compound is
Hexane (C6H12), retention time 3.65 and trace mass 41,compound is 1-Heptene (C7H14), retention
time 3.77 and trace mass 43, compound is Heptane (C7H16), retention time 5.19 and trace mass 41,
compound is 1-Octene (C8H16), retention time 5.34 and trace mass 43, compound is Octane
(C8H18), retention time 6.92 and trace mass 41,compound is 1-Nonene (C9H18), retention time 7.07
and trace mass 43,compound is Nonane (C9H20), retention time 8.64 and trace mass 41,compound is
Int. J. Pure Appl. Sci. Technol., 11(2) (2012), 36-44.
41
1-Decene (C10H20), retention time 8.79 and trace mass 43, compound is compound is Decane
(C10H22), retention time 10.30 and trace mass 41, compound is 1-Undecene (C11H22), retention
time 10.43 and trace mass 43, compound is Undecane (C11H24) ,retention time 11.85 and trace mass
41, compound is 1-Decene (C10H24), retention time 11.98 and trace mass 57, compound is Dodecane
(C12H26), retention time 13.32 and trace mass 41, compound is 3-Tridecene,(E)- (C13H28), retention
time 13.45 and trace mass 43, compound is Tridecane (C13H28), retention time 14.60 and trace mass
70, compound is 3-Tetradecene,(E)- (C14H28) , retention time 14.82 and trace mass 71, compound is
Tetradecane (C14H30), retention time 16.01 and trace mass 43, compound is 1-Pentadecene
(C15H30), retention time 16.12 and trace mass 57, compound is Pentadecane (C15H32), retention
time 17.24 and trace mass 41, compound is 1-Hexadecene (C16H32), retention time 17.35 and trace
mass 43, compound is Hexadecane (C16H34), retention time 18.40 and trace mass 43, compound is
E-14-Hexadecenal, (C16H30O), retention time 18.50 and trace mass 57, compound is Heptadecane
(C17H36), retention time 19.51 and trace mass 43, compound is E-15-Heptadecenal (C17H32O),
retention time 20.65 and trace mass 71, compound is Nonadecane (C19H40), retention time 21.65 and
trace mass 57, compound is Eicosane (C20H42), retention time 22.61 and trace mass 85 , compound
is Heneicosane (C21H44) etc. In the ultimate phase of the analysis index at retention time 23.51 and
trace mass 71, compound is Heneicosane (C21H44), retention time 24.39 and trace mass 43, and
compound is Heneicosane (C21H44) as well, retention time 25.24 and trace mass 57, compound is
Tetracosane (C24H50), retention time 26.06 and trace mass 57, compound is Heneicosane (C21H44),
retention time 26.86 and trace mass 57, compound is Octacosane (C28H58), retention time 26.86 and
trace mass 57, compound is Octacosane (C28H58), retention time 29.20 and trace mass 57,
compound is Octacosane (C28H58) and eventually retention time 29.97 and trace mass 57, compound
is Heptacosane (C28H58) respectively.
70.0
65
60
2026.40
55
50
3618.53
45
2332.06
1821.23
40
35
%T
30
1716.17
1606.78
633.39
25
20
813.34
1076.40
15
10
2672.73
5
991.78
2730.56
1378.50
1302.76
0
3077.01
965.08
1641.60
2932.59
887.81
1465.79
909.32
721.33
-4.0
4000.0
3600
3200
2800
2400
2000
1800
1600
1400
1200
1000
cm-1
Figure 3: FT-IR spectrum of LDPE waste plastic to diesel grade fuel
800
600
450.0
Int. J. Pure Appl. Sci. Technol., 11(2) (2012), 36-44.
42
Table 2: LDPE waste plastic to diesel fuel functional group name
Number of
Wave
1
2
Wave
Number
(cm-1)
3618.53
3077.01
3
4
5
8
2932.59
2730.56
2672.73
1821.23
9
1716.17
10
1641.60
Functional
Group
Name
Free OH
H Bonded
NH
C-CH3
C-CH3
C-CH3
NonConjugated
NonConjugated
NonConjugated
Number of
Wave
Functional
Group Name
11
12
Wave
Number
(cm-1)
1606.78
1465.79
13
16
17
18
1378.50
991.78
965.08
909.32
CH3
-CH=CH2
-CH=CH-(cis)
-CH=CH2
19
887.81
C=CH2
21
721.33
-CH=CH-(cis)
Conjugated
CH3
FT-IR analysis of LDPE waste plastic to diesel grade fuel or 4th fractional fuel (Figure 3 and Table
2) shows the following types of functional groups at wave number 3618.53 cm-1, derived functional
group is Free OH, wave number 3077.01 cm-1, functional group is H bonded NH, wave number
2932.59 cm-1,2730.56 cm-1 and 2672.73 cm-1 functional group is C-CH3, wave number 1821.23 cm-1,
1716.17 cm-1, and 1641.60 cm-1 functional group is Non-Conjugated, wave number 1606.78 cm-1
functional group is Conjugated. As well as wave number 1465.79 cm-1 and 1378.50 cm-1 functional
group is CH3,wave number 991.78 cm-1 and 909.32 cm-1,functional group is -CH=CH2 and ultimately
wave number 887.81 cm-1 functional group is C=CH2 and wave number 721.33 cm-1 functional group
is -CH=CH-(cis). Energy values are calculated for all functional group and using formula is E=hυ,
Where h=Planks Constant, h =6.626x10-34 J, υ= Frequency in Hertz (sec-1), Where υ=c/λ, c=Speed of
light, where, c=3x1010 m/s, W=1/λ, where λ is wave length and W is wave number in cm-1. Therefore
the equation E=hυ, can substitute by the following equation, E=hcW. According to their wave
number such as for 3618.53 (cm-1) calculated energy value is 7.18x10-20 J, wave number such as for
3077.01 (cm-1) calculated energy value is 6.11x10-20 J , 2932.59 (cm-1) calculated energy, E=5.82x1020
J, wave number such as for 2730.56 (cm-1) calculated energy value is 5.42x10-20 J, wave number
such as for 2672 (cm-1) calculated energy value is 5.30x10-20 J. Similarly, wave number 1821.23 (cm1
) energy, E =3.61x10-20 J, wave number 1716.17 (cm-1), energy, E =3.40x10-20 J, wave number
1606.78 (cm-1), energy, E =3.19x10-20 J , wave number 1465.79 (cm-1), energy, E =2.91x10-20 J, wave
number 1378.50 (cm-1) energy, E = 2.73x10-20 J, wave number 991.78 (cm-1), energy, E =1.97x10-20 J,
wave number 965.08 (cm-1), energy, E =1.91x10-20 J, wave number 909.32 (cm-1), energy, E
=1.80x10-20 J, wave number 887.81 (cm-1), energy, E =1.76x10-20 J and eventually wave number
721.33 (cm-1) functional group is 1.43x10-20 J respectively.
Int. J. Pure Appl. Sci. Technol., 11(2) (2012), 36-44.
43
Figure 4: DSC graph of LDPE waste plastic to diesel grade fuel
Diesel grade fuel collected from LDPE waste plastic and diesel grade fuel (Figure 4) was analyzed by
using DSC equipment for messaging boiling point temperature and enthalpy value. The fractional
temperature range was for diesel grade fuel collection during production period at 260-285 ºC. This
temperature is giving longer hydrocarbon compounds based on their boiling point range wise. Perkin
Elmer DSC analysis graph showed in this fuel onset temperature is 14.74 ºC, peak temperature is
205.50 ºC, peak height is 36.3382 mW, area is 18116.139 mJ and enthalpy delta H value is
18116.1385 J/g. Peak height is representing heat Endo up 50% from total 100%. This fuel
hydrocarbon compounds are heavier and fuel hydrocarbon compounds mixtures of alkane and alkene
groups. This fuel is giving us high boiling point because this fuel has heavier long chain hydrocarbon
compounds as usual. Fuel analysis temperature profile indicates that 17.53% fuel was boiled at 100 ºC
and 100% fuel boiled was 396 ºC.
4. Conclusion:
Most of the LDPE plastic is using as shopping bag and LDPE waste plastic percentage is 23 % from
total waste plastics. LDPE waste plastic problem is biggest environmental concern because LDPE
waste plastic thin and light for that reason every sector are using LDPE plastic. For saving the
environmental problems from LDPE waste plastic can convert into diesel grade fuel by using thermal
degradation with fractional distillation process without adding any kind of catalyst or chemicals in
this process. Produce fuel density is 0.80 g/ml which is similar density like commercial diesel fuel.
Produced diesel fuel was analysis by GC/MS and found hydrocarbon compounds range showed
GC/MS chromatogram Propane (C3H8) to Octacosane (C28H58). Because initial raw material has
straight chain hydrocarbon which was break down into short chain hydrocarbon as well as long chain
hydrocarbon by using thermal and fractional distillation process. Produce fuel could be use in internal
combustion engine and feed for feed stock refinery or using diesel grade fuel could be generated
electricity as well.
Int. J. Pure Appl. Sci. Technol., 11(2) (2012), 36-44.
44
Acknowledgement:
The authors acknowledge the support of Dr. Karin Kaufman, the founder and sole owner of Natural
State Research, Inc. The authors also acknowledge the valuable contributions NSR laboratory team
members during the preparation of this manuscript.
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