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Pyrolysis of a fraction of mixed plastic wastes depleted in PVC
Journal cl
4rla+icsl and Applkd Pyrolysis
w-41
ELSEVIER
(IW7)
365-371
Pyrolysis ol”a fraction of mixed plastic wastes depleted in PVC ho-Sik
A
Kim *, W. Kaminsky, B. Schlesselmann
hction of plastic wastts from DSD (Dules System Dcutschlandj uphich is depleted in
(PVC) was pyrolyzed at 638, 690 and 73X in 3 technical-scale flukiizcd bed reactor. At 638OC over 50 wt.% of the pyrolysis product *as an oil with a boiling point less than 295% this can be usd as feedstock in a steam cracker. The expcrimcnt at 6!WC yielded about 40 wt.% of an oil, about the half of which consists of bilZeoC. tolu~t~ and xylenc (BlXuromntics). At the highest reaction temperature of 73YC. the main product was a highly aromatized oil; the EWX-aromatics content is about 20 wt.% of the pyrolysis product. 0 1597 Hsevier Science 3-V.
polyvinylchloride
K~JwJ~~ -_-
Fluidized bed; Pyrolysis; HTX-aromatics
Much intensive research has recently focused on solving problems cau& by plastic wastes, and some possibilities [I -31, not yet used to their full potential, seem to be have bPen found. One of them is a process developed at the University of Hamburg. This has been developed in o&r to gain petrochcrnicai oils and eases of high caloric value fram plastic wastes. Nowadays the target of the research using the Hamburg Process has diversified and can be classified into three categories; 1. TO ru.AnIre the yields of benzene, toluene, xylene (BTX-aromatics) or aIiphatic oils from mixed plastic wstev [41. Corresponding author.
??
0165-2~7O!W:Si7.KJQ 1997 Elxvier Science B.V. All rights rcscrwd. Ptf SOl65-2370(97)00042-9
2. To maximize the yields of monomers from polymers, such as poly(methylmethhcrylate) and polystyrene [S]. 3. To maximize the yields of olcfins from polyolefin wastes (61, This paper contains the results of three experiments using the technical-scale Aarnburg Process (Fig. 1). The goal was to maximize the yields of BTX-aromatics or aliphatic oils from plastic wastes collected and separated by the DSD (kales Sysrem Deuischland). The% were selected to be depleted in polyvinylchloride (PVC).
2. Experimntaf
The pyroIysis plant at the University of Hamburg was designed and constructed 1976. Since then, it has been reconstructed and expanded sever<imes. Some supplements, e,g., a prtscesscontrol system, have been add& The main body of the reactor is made of stainless steel. It consists of three parts. The lower tube which contains the fluidized bed and has a diameter of 0.45 m, The height of this tube is limited to 0.65 III by the middle part which has an overflow vessel and connects the lower tube and the upper tube. The upper tube has a diameter of OAm and a height of I.08 m. The separation sytem contains a cyclone, quench cooler, scrubber und electrostatic precipitator. Previous rem” ,,__.. give G!! details of the plant [S-7]. in
Fig. I.
I.-S+ Kim Ed al. iJ. Ami. Appl. P~rolpti 40-41 (19971 MS-372
r!xpcrimcnt
@I
E2
E3
Tmpcrature I’C) Residence time in reactor (s!
63%
690
735 9
Amcmt of input (kg? Duration {h) Feed I;ltt [kg h-‘1 Quench medium
84 5 17.5 Toluene
367
-_-
Enput of sbwbent -..
(kt)
8
8
4.8
321 22 14.6
Mix of xyleoe and ethyllmxenc 12,o
430 z9 14.8 Mix of xykne and ahyltm-
mlc IO.1
Two types of material, the differen= of which lies in the mc?hd of cltibtion, were used for the experiments. In El and E2 (see Table I) plastic wastes were sorted
as electropositive and then separated in a stream ofair. The light fraction tier air separation, which was again deformed as agglomclrte at 13X. was wed as the feed material. According to the analysis of DSD, .:he composition was W-75% polyokfin, IO-20% polystyrene, 4-S% polyvinykhloride, and 5- 10%other wastes. The clcmtntal analysis (Table 2) shows that 1.9 wt.% of Cl existed in the material. in a sodium In the case of E3 (see Table !, too), the ptsstic wastes were tmtai chloride soWon in a worm-conveyor centrifuge, from which the low density w &es were separated. The material transferred from IXD had to be red& in *sizeto pellets, as it was inadequate for the input system. Elemental analysis and the analysis frcrm density separation showed that the material consisted of 79-75% polyolefin, 25-300/o polystyrene, and O-5% polyvi~ykhloride, The feed material contained 0.63 wt.% of chlorine. Lime was fed in addition to the plastic wastes, in order to capture HCI produced during the pyrolysis.
Table 2 Elemental analysis and composition of the feed mattrialo Component
El and E2 (m.%)
E3 (m.%) -
Carbim Hyd%W
Nitrogen Chlorine water lllO&WlkX “.1_-.-
74.0
79.8
Irl.i 0.4 1.9 4.!!
10.6 0.2 0.6 4. f
4.0 -.....
I.9 -.
.. .. _ _
_
Some parameters of the experiments are listed in Table I. The exp-erimentEl. the reaction temperature of which was 638*C,has as its target a high yield in aliphatic
oil. The lluidizing stream was srelcctedso that the effect of temperature on the mass balance of the products in El could be compared directly with that in E2. In contrast to El, in E2 and E3 the optimal reaction temperature to yield the maximal content of BTX-aromatics was investigated. Pyrolysis gas was used as the fluidizing medium for all three experiments.
Gases. oils, solid residues and water were obtained as pyrolysis product fractions. A representative sample of oil was distilled in a bench-scale apparatus (210°C, 13.3 kPa) to give a fraction of oil and residue. The gases and oils were analysed by GC and GC/MS. All the fractions of the products were also analysed elementally, In addition, the content of chlorine in all the fractions was determined.
3. Results and discussIon Table 3 shows the mass balance of the experiments, referring to the total organic input. The sum of the oil in El is about 50 wt.%. The sums of the BTX-aromatics in E2 and E3 are about 18 wt.% and 20 wt.%, respectively.
In all the experiments the gases consist chiefly of methane, ethenc and propene. Especiallyin El and E2 more carbon monoxide and -dioxide are produced, because of the higher content of oxygen m the feed material than that in E3. The experiments El and E2, which were carried out with the same material, show that the content of gas increases as the temperature rises, The amount of the gas in E3 is less than that in the experiments E2, is due to the higher content of polystyrene, which is converted to a great extent into oil during pyrolysis, in the feed material.
In El much of aliphatic oil is produced on the basis of the relatively low reaction temperature. in the case of E2 and E3, in which the reaction temperatures are selected so that the maximum amount of BTX-aromatics can be produced, the content of BTX-aromatics amounts to about 20 wt.% of the products. The amount of BTX- aromatics increases as rhr reaction temperature rises, In contrast, the amount of styrene decreaseswith increasing temperature, as shown in El and E2. The increased amount ol styrene in E3 is due to the higher content of polystyrene in feed material.
Temperature (“C)
638 (El)’
690 (EZr
735 (E3yl
-
Gases
37.0
42.9
35.0
HydraSen Carbon monoxide Carbon dioxide Methane Ethcnc Ethanc
0.3 3.4 2.4 7.3 7.6
0.5 4.7 2.2 14.1 ID.7
0.4 1’ .L 0.4 11.9 8.9
3.7
Propcnc
6.9
4.5 4.5
3.9 5.0
2.0 17.3 b.8
41.0 3.2 3.1 0. I 18.7 11.6
48.4 3.6 3.5 0.1 20.6 9.1
a.1 1.7 17.7 3.0 10.2 1.3 0.6 0.7 0.4 n.db 0.1 5.8 5.4
5.9 1.24 15.4 0.8 6.4 I.2 I.1 2.8 I.1 0.01 1.1 10.8 4.8
Dils Aliphatic oil CSC7 Hydrocxbons cW.20 Hydroccurbons BTX-aromatics Benzene Tolueni Xytent Orher arom*tin Ethylknzcnc SlywIle Mrthylstyrcnc lndrne Naphthakne Sicthynaphthalcnes Nitrogen comvmds Oxygen compound Distillation nsiduc soot
51.8 I5.D 13.0
7.6 3.9 24.3 2.5 IO.8 I.6 1.2 2.3 I.U D.02 n.d 14.3 2.2
’ Mass bdancc (wt.%.) b n.d. Not dttcctcd.
3.3. Disrillation residue The distillation k, 3, s in E2 and E3 (bp > 21OOC.13.3 kPa) are highly aromatic with a C/H ratio (Table 4) of about 1.1. In contrast to E2 and E3, the distillation residue of El has an aliphatic character. Table 4 C/H ratio of the products Reaction temperature (‘C)
638 (El)
690 (E?r
735 tE3)
oil
0.84 0 79 I28
fi.8? 1.10 2.03
0.85 I .07 I .07
Distillation residue soot
~
--
Table 5 Distribution Experiment
of chlcrine
over the products
(E2)
Chlorine in input (g) Plastic wastes Lime Chlorine in output (g) Oil Dist. rcsiduc SCM ikd malcriat W&r Recovery rate I%)
in EZ” (m.%) --
(d) 6099.36 6099 0.36 3024.61 3.37 7.29 2527.81 488.04 0.1 50.38
_. ._...
: .!:0 3.00 E-03 1.72 E-03 0.02
I I xl 0.28
I .a0 E-03 -
._.-_
” Rcacliontemperaturrr: @WC.
Fine particles of sand or inorganics in the feed material wcrc swept away by the of pyrolysis gas and then precipitated in tht- ryslnn~ with !he KY!!, whkh mainly consists of aromatic solids and carbon black. stream
3.5. Wuter After the distilIation in the technical-scale apparatus, a porlion of water was separated from the pyrolysis oil, The water in $22and E3 was basic with a pH IO, The basic character of the water is due to atnmonia dissolved in the water and derived from polymer containing nitrogen element, for instance polyamide, in the feed material.
In order to avoid the corrosion by chlorine during the petrochemical processing, the content of chlorine, particularly in oil, must be low. The product oils in the three experiments should contain less than IO ppm of chlcr:ne ~:t the request of petrochemical industries. Table S show: the distribution of chlorine in E2 over the product fractions. Must of it was found in the distillation residue and the soot. About the half crfchlorine was recovered, The recovery rale of 50% results on one hand from the p--ihI uti.ut Ity crf inuccutacy of the chlorine andysis, on the other hand from some amount of soot which sticked to the w:rl!of the reactor and rhe pipeline of the plant.
J.-S. Kint CI al. ,‘J. Aml. Appl. Pqrol~sis 40-41 (1997) 365-371
371
4. comparkioa Some other projects are now in progress on the puq~~ of the recycling of pIas& wastes, for instance BASF in Germany [a]. But the wmparision with expeUcntal data ofother companies is dimuh in a great part owing tr; different feed materials 3”A ‘AU1-b “*“kaf &-%:i!cdlitcraturcs. Table 5 sho!vs tt-4%,GSults -(SIMON [q; KIM [9]) of two experiments at 700 and 738°C in a laboratory scak plant at Uni. of Hamburg. SIMON used steam as a fluididng medium. in order to obtain high yields of okfins. The sum of ethylene and propylene amounts to M wt.%. KIM’s laboratory experiment was carried out with the sIlmcfeed material 8s that in E3, but the great difference is the residence time in t!s fluidi& bed. KIM’s result shows a relative high yield of oils in spite of the higher reaction temperature, owing to the about four times shorter resideace time than that in E3 [9]_
Tublc 6 Comparison OFthe results _Experiment
E3 (73DY
SlMON
{7DD)*
Feed marcriaI Pyrolysis plant Ftuidizing gas Residence rk,ic (I)
MPWlb Teebnkal Pyrolysis gas 8.8
Laboratory H,O No intormation
KIM
MPWF
PrcHJltcts (W1.s) GilSCS Hydrogen Carbon monoxide Carbon dioxide Methane Efhane Ethane Propene
35 0.4 1.2 0.4 11.9 8.9 3.9 5.0
“Temperature (‘Cl. t The compositiou of the mixed plastt waste is shown in Table 2. L‘ This feed material consists of about 73 wt.% PE/PP, 26 nt.% E% and
37
(i.7 1.3 0.6 2D.3 10.8 1.9 0.8
I I&% PVC.
(Xi
372
J.-S. Kim FI ul. ;f.
Ad.
Appt.
P~rnlpi~
40-41
(1997)
365-372
5. Conclusion From the resulfs of the three experiments, it is shuwn that the Hamburg Process is capable of recycling the mixed plaslic wastes. Over 50 wt.% of oil. where aliphatics amount to about 3oU4, was produced at the reaction temperature of 638°C. This oil. owing to the relative high content of aiiphatics, could be used as feedstock in a sleam cracker. In the experiments E2 and E3, about 18 wt.% of BTX-aromatics was formed. Significantly, the product oil 11; E3 has a very low chlorine content. which allows this oil to be used in petrochemical processing. The gas produced during the pyrolysis can be used as a fuel gas. The gas produced in E3 has a calorific value of about 50 MJ/kg. The distillation residue could also be used LS a heating source. Another advantage of the process is that chlorine is concentrated in solid products which is easily removed. In addition, the product oils contain almost no metals, which reduces the processing cost. But from the results of E2 and E3, in which the feed material contains about 2 wt.% chlorine, the product oils contain about 20 ppm of chlorine. In order to solve this problem, some further work is now in progress.
References [I] G. Menges (Ed.], Recycling von KunslstolT. Hacw Vcrldg. Munchcn, 1992. [I] H. Sutter (Ed.). Erfassung und Verwertung von Kunstaofl’, EF-Verlag. Berlin. 1993. [3] J.H. Brophy. S. Hardman, in: H. Sutter (Ed.), E&ssung und Venvertung von Kunsrstolf. lag. Berlin. 1993. p. 426. [4] R. Rahncnfiiihrer. Ph.D. Thesis, University of Hamburg 1993. [51 W. Kuminsky, J. Frank, J. Anal. Appl. Pyrolysis 19 (1991) 311. [6] W. Kaminsky. B. Schlesselmann. C. Simon, J. Anal. Appl. Pyrolysis 32 (1995) 19. [7] W. Kaminsky. H. Rdsslcr. Chemrech 2 (1992) IO& [R] M. Ciebiuer. Lruna. RohstofIliches Recycling von Ahkunstsloffen, [9] Joo-Sik Kim. Dissertation. University of Hamburg. in manuscript,
EF-Ver-
KunststofTe 85 (1995) 3.
4rla+icsl and Applkd Pyrolysis
w-41
ELSEVIER
(IW7)
365-371
Pyrolysis ol”a fraction of mixed plastic wastes depleted in PVC ho-Sik
A
Kim *, W. Kaminsky, B. Schlesselmann
hction of plastic wastts from DSD (Dules System Dcutschlandj uphich is depleted in
(PVC) was pyrolyzed at 638, 690 and 73X in 3 technical-scale flukiizcd bed reactor. At 638OC over 50 wt.% of the pyrolysis product *as an oil with a boiling point less than 295% this can be usd as feedstock in a steam cracker. The expcrimcnt at 6!WC yielded about 40 wt.% of an oil, about the half of which consists of bilZeoC. tolu~t~ and xylenc (BlXuromntics). At the highest reaction temperature of 73YC. the main product was a highly aromatized oil; the EWX-aromatics content is about 20 wt.% of the pyrolysis product. 0 1597 Hsevier Science 3-V.
polyvinylchloride
K~JwJ~~ -_-
Fluidized bed; Pyrolysis; HTX-aromatics
Much intensive research has recently focused on solving problems cau& by plastic wastes, and some possibilities [I -31, not yet used to their full potential, seem to be have bPen found. One of them is a process developed at the University of Hamburg. This has been developed in o&r to gain petrochcrnicai oils and eases of high caloric value fram plastic wastes. Nowadays the target of the research using the Hamburg Process has diversified and can be classified into three categories; 1. TO ru.AnIre the yields of benzene, toluene, xylene (BTX-aromatics) or aIiphatic oils from mixed plastic wstev [41. Corresponding author.
??
0165-2~7O!W:Si7.KJQ 1997 Elxvier Science B.V. All rights rcscrwd. Ptf SOl65-2370(97)00042-9
2. To maximize the yields of monomers from polymers, such as poly(methylmethhcrylate) and polystyrene [S]. 3. To maximize the yields of olcfins from polyolefin wastes (61, This paper contains the results of three experiments using the technical-scale Aarnburg Process (Fig. 1). The goal was to maximize the yields of BTX-aromatics or aliphatic oils from plastic wastes collected and separated by the DSD (kales Sysrem Deuischland). The% were selected to be depleted in polyvinylchloride (PVC).
2. Experimntaf
The pyroIysis plant at the University of Hamburg was designed and constructed 1976. Since then, it has been reconstructed and expanded sever<imes. Some supplements, e,g., a prtscesscontrol system, have been add& The main body of the reactor is made of stainless steel. It consists of three parts. The lower tube which contains the fluidized bed and has a diameter of 0.45 m, The height of this tube is limited to 0.65 III by the middle part which has an overflow vessel and connects the lower tube and the upper tube. The upper tube has a diameter of OAm and a height of I.08 m. The separation sytem contains a cyclone, quench cooler, scrubber und electrostatic precipitator. Previous rem” ,,__.. give G!! details of the plant [S-7]. in
Fig. I.
I.-S+ Kim Ed al. iJ. Ami. Appl. P~rolpti 40-41 (19971 MS-372
r!xpcrimcnt
@I
E2
E3
Tmpcrature I’C) Residence time in reactor (s!
63%
690
735 9
Amcmt of input (kg? Duration {h) Feed I;ltt [kg h-‘1 Quench medium
84 5 17.5 Toluene
367
-_-
Enput of sbwbent -..
(kt)
8
8
4.8
321 22 14.6
Mix of xyleoe and ethyllmxenc 12,o
430 z9 14.8 Mix of xykne and ahyltm-
mlc IO.1
Two types of material, the differen= of which lies in the mc?hd of cltibtion, were used for the experiments. In El and E2 (see Table I) plastic wastes were sorted
as electropositive and then separated in a stream ofair. The light fraction tier air separation, which was again deformed as agglomclrte at 13X. was wed as the feed material. According to the analysis of DSD, .:he composition was W-75% polyokfin, IO-20% polystyrene, 4-S% polyvinykhloride, and 5- 10%other wastes. The clcmtntal analysis (Table 2) shows that 1.9 wt.% of Cl existed in the material. in a sodium In the case of E3 (see Table !, too), the ptsstic wastes were tmtai chloride soWon in a worm-conveyor centrifuge, from which the low density w &es were separated. The material transferred from IXD had to be red& in *sizeto pellets, as it was inadequate for the input system. Elemental analysis and the analysis frcrm density separation showed that the material consisted of 79-75% polyolefin, 25-300/o polystyrene, and O-5% polyvi~ykhloride, The feed material contained 0.63 wt.% of chlorine. Lime was fed in addition to the plastic wastes, in order to capture HCI produced during the pyrolysis.
Table 2 Elemental analysis and composition of the feed mattrialo Component
El and E2 (m.%)
E3 (m.%) -
Carbim Hyd%W
Nitrogen Chlorine water lllO&WlkX “.1_-.-
74.0
79.8
Irl.i 0.4 1.9 4.!!
10.6 0.2 0.6 4. f
4.0 -.....
I.9 -.
.. .. _ _
_
Some parameters of the experiments are listed in Table I. The exp-erimentEl. the reaction temperature of which was 638*C,has as its target a high yield in aliphatic
oil. The lluidizing stream was srelcctedso that the effect of temperature on the mass balance of the products in El could be compared directly with that in E2. In contrast to El, in E2 and E3 the optimal reaction temperature to yield the maximal content of BTX-aromatics was investigated. Pyrolysis gas was used as the fluidizing medium for all three experiments.
Gases. oils, solid residues and water were obtained as pyrolysis product fractions. A representative sample of oil was distilled in a bench-scale apparatus (210°C, 13.3 kPa) to give a fraction of oil and residue. The gases and oils were analysed by GC and GC/MS. All the fractions of the products were also analysed elementally, In addition, the content of chlorine in all the fractions was determined.
3. Results and discussIon Table 3 shows the mass balance of the experiments, referring to the total organic input. The sum of the oil in El is about 50 wt.%. The sums of the BTX-aromatics in E2 and E3 are about 18 wt.% and 20 wt.%, respectively.
In all the experiments the gases consist chiefly of methane, ethenc and propene. Especiallyin El and E2 more carbon monoxide and -dioxide are produced, because of the higher content of oxygen m the feed material than that in E3. The experiments El and E2, which were carried out with the same material, show that the content of gas increases as the temperature rises, The amount of the gas in E3 is less than that in the experiments E2, is due to the higher content of polystyrene, which is converted to a great extent into oil during pyrolysis, in the feed material.
In El much of aliphatic oil is produced on the basis of the relatively low reaction temperature. in the case of E2 and E3, in which the reaction temperatures are selected so that the maximum amount of BTX-aromatics can be produced, the content of BTX-aromatics amounts to about 20 wt.% of the products. The amount of BTX- aromatics increases as rhr reaction temperature rises, In contrast, the amount of styrene decreaseswith increasing temperature, as shown in El and E2. The increased amount ol styrene in E3 is due to the higher content of polystyrene in feed material.
Temperature (“C)
638 (El)’
690 (EZr
735 (E3yl
-
Gases
37.0
42.9
35.0
HydraSen Carbon monoxide Carbon dioxide Methane Ethcnc Ethanc
0.3 3.4 2.4 7.3 7.6
0.5 4.7 2.2 14.1 ID.7
0.4 1’ .L 0.4 11.9 8.9
3.7
Propcnc
6.9
4.5 4.5
3.9 5.0
2.0 17.3 b.8
41.0 3.2 3.1 0. I 18.7 11.6
48.4 3.6 3.5 0.1 20.6 9.1
a.1 1.7 17.7 3.0 10.2 1.3 0.6 0.7 0.4 n.db 0.1 5.8 5.4
5.9 1.24 15.4 0.8 6.4 I.2 I.1 2.8 I.1 0.01 1.1 10.8 4.8
Dils Aliphatic oil CSC7 Hydrocxbons cW.20 Hydroccurbons BTX-aromatics Benzene Tolueni Xytent Orher arom*tin Ethylknzcnc SlywIle Mrthylstyrcnc lndrne Naphthakne Sicthynaphthalcnes Nitrogen comvmds Oxygen compound Distillation nsiduc soot
51.8 I5.D 13.0
7.6 3.9 24.3 2.5 IO.8 I.6 1.2 2.3 I.U D.02 n.d 14.3 2.2
’ Mass bdancc (wt.%.) b n.d. Not dttcctcd.
3.3. Disrillation residue The distillation k, 3, s in E2 and E3 (bp > 21OOC.13.3 kPa) are highly aromatic with a C/H ratio (Table 4) of about 1.1. In contrast to E2 and E3, the distillation residue of El has an aliphatic character. Table 4 C/H ratio of the products Reaction temperature (‘C)
638 (El)
690 (E?r
735 tE3)
oil
0.84 0 79 I28
fi.8? 1.10 2.03
0.85 I .07 I .07
Distillation residue soot
~
--
Table 5 Distribution Experiment
of chlcrine
over the products
(E2)
Chlorine in input (g) Plastic wastes Lime Chlorine in output (g) Oil Dist. rcsiduc SCM ikd malcriat W&r Recovery rate I%)
in EZ” (m.%) --
(d) 6099.36 6099 0.36 3024.61 3.37 7.29 2527.81 488.04 0.1 50.38
_. ._...
: .!:0 3.00 E-03 1.72 E-03 0.02
I I xl 0.28
I .a0 E-03 -
._.-_
” Rcacliontemperaturrr: @WC.
Fine particles of sand or inorganics in the feed material wcrc swept away by the of pyrolysis gas and then precipitated in tht- ryslnn~ with !he KY!!, whkh mainly consists of aromatic solids and carbon black. stream
3.5. Wuter After the distilIation in the technical-scale apparatus, a porlion of water was separated from the pyrolysis oil, The water in $22and E3 was basic with a pH IO, The basic character of the water is due to atnmonia dissolved in the water and derived from polymer containing nitrogen element, for instance polyamide, in the feed material.
In order to avoid the corrosion by chlorine during the petrochemical processing, the content of chlorine, particularly in oil, must be low. The product oils in the three experiments should contain less than IO ppm of chlcr:ne ~:t the request of petrochemical industries. Table S show: the distribution of chlorine in E2 over the product fractions. Must of it was found in the distillation residue and the soot. About the half crfchlorine was recovered, The recovery rale of 50% results on one hand from the p--ihI uti.ut Ity crf inuccutacy of the chlorine andysis, on the other hand from some amount of soot which sticked to the w:rl!of the reactor and rhe pipeline of the plant.
J.-S. Kint CI al. ,‘J. Aml. Appl. Pqrol~sis 40-41 (1997) 365-371
371
4. comparkioa Some other projects are now in progress on the puq~~ of the recycling of pIas& wastes, for instance BASF in Germany [a]. But the wmparision with expeUcntal data ofother companies is dimuh in a great part owing tr; different feed materials 3”A ‘AU1-b “*“kaf &-%:i!cdlitcraturcs. Table 5 sho!vs tt-4%,GSults -(SIMON [q; KIM [9]) of two experiments at 700 and 738°C in a laboratory scak plant at Uni. of Hamburg. SIMON used steam as a fluididng medium. in order to obtain high yields of okfins. The sum of ethylene and propylene amounts to M wt.%. KIM’s laboratory experiment was carried out with the sIlmcfeed material 8s that in E3, but the great difference is the residence time in t!s fluidi& bed. KIM’s result shows a relative high yield of oils in spite of the higher reaction temperature, owing to the about four times shorter resideace time than that in E3 [9]_
Tublc 6 Comparison OFthe results _Experiment
E3 (73DY
SlMON
{7DD)*
Feed marcriaI Pyrolysis plant Ftuidizing gas Residence rk,ic (I)
MPWlb Teebnkal Pyrolysis gas 8.8
Laboratory H,O No intormation
KIM
MPWF
PrcHJltcts (W1.s) GilSCS Hydrogen Carbon monoxide Carbon dioxide Methane Efhane Ethane Propene
35 0.4 1.2 0.4 11.9 8.9 3.9 5.0
“Temperature (‘Cl. t The compositiou of the mixed plastt waste is shown in Table 2. L‘ This feed material consists of about 73 wt.% PE/PP, 26 nt.% E% and
37
(i.7 1.3 0.6 2D.3 10.8 1.9 0.8
I I&% PVC.
(Xi
372
J.-S. Kim FI ul. ;f.
Ad.
Appt.
P~rnlpi~
40-41
(1997)
365-372
5. Conclusion From the resulfs of the three experiments, it is shuwn that the Hamburg Process is capable of recycling the mixed plaslic wastes. Over 50 wt.% of oil. where aliphatics amount to about 3oU4, was produced at the reaction temperature of 638°C. This oil. owing to the relative high content of aiiphatics, could be used as feedstock in a sleam cracker. In the experiments E2 and E3, about 18 wt.% of BTX-aromatics was formed. Significantly, the product oil 11; E3 has a very low chlorine content. which allows this oil to be used in petrochemical processing. The gas produced during the pyrolysis can be used as a fuel gas. The gas produced in E3 has a calorific value of about 50 MJ/kg. The distillation residue could also be used LS a heating source. Another advantage of the process is that chlorine is concentrated in solid products which is easily removed. In addition, the product oils contain almost no metals, which reduces the processing cost. But from the results of E2 and E3, in which the feed material contains about 2 wt.% chlorine, the product oils contain about 20 ppm of chlorine. In order to solve this problem, some further work is now in progress.
References [I] G. Menges (Ed.], Recycling von KunslstolT. Hacw Vcrldg. Munchcn, 1992. [I] H. Sutter (Ed.). Erfassung und Verwertung von Kunstaofl’, EF-Verlag. Berlin. 1993. [3] J.H. Brophy. S. Hardman, in: H. Sutter (Ed.), E&ssung und Venvertung von Kunsrstolf. lag. Berlin. 1993. p. 426. [4] R. Rahncnfiiihrer. Ph.D. Thesis, University of Hamburg 1993. [51 W. Kuminsky, J. Frank, J. Anal. Appl. Pyrolysis 19 (1991) 311. [6] W. Kaminsky. B. Schlesselmann. C. Simon, J. Anal. Appl. Pyrolysis 32 (1995) 19. [7] W. Kaminsky. H. Rdsslcr. Chemrech 2 (1992) IO& [R] M. Ciebiuer. Lruna. RohstofIliches Recycling von Ahkunstsloffen, [9] Joo-Sik Kim. Dissertation. University of Hamburg. in manuscript,
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