Pyrolysis—Catalytic Reforming of Br-HIPS Over Fe- and Ni- Modified Catalysts
C. Ma, J. Yu, B. Wang, Z.J. Song, Q.Q. Yan, L.S. Sun*
State Key Laboratory of Coal Combustion
Huazhong University of Science and Technology
1
21-06-2017 Athens, Greece
Contents
Experimental
Results & Discussion
Background
2
Conclusion
China
Worldwide
41.8Mt in 2014, expected to 50 Mt in 2018
5.52Mt in 2013, expected to 20 Mt in 2040
Numerous e-wasteWaste of resourceEnvironmental problems
3
Background
INCINERATION
RECYCLING
LANDFILL
TRASH
TRASHGreenhouse gas Mercury Dioxins
“ZERO LANDFILL”in 2025
30.8%
39.5%
29.7%
Leaching of toxic metals and chemicals into the soil.
Source : National Bureau of Statistics of China (2014); PlasticEurope (2015)
Increasing quantity of e-waste
Potential secondary resources
Economicbenefit
Social benefit
Environmentalbenefit
4
Background
Material Kilotons MillionEuros
METALIron,Steel 16,500 9,000Copper(Cu) 1,900 10,600Aluminum(Al) 220 3,200Precious MetalsGold(Au) 0.3 10,400Silver(Ag) 1 580Palladium(Pd) 0.1 1,800PLASTICSPP, ABS, PC, PS 8,600 12, 300
48 Billion EUROS
CHEMICALS
Poly-/Brominated Flame Retardants PhosphorsPCBs/A Polychlorinated biphenylHexavalent chromium (PW)Ozone depleting substances (CFCs, HCFC, HFC, HCs)
METALSMercury, CadmiumChromiumLead
Source :Baldé et al., United Nations University, IAS – SCYCLE(2015)
30% of WEEE
56% of BFR
186,000 tonsBFR-plastics
Significance of recycling e-waste plastics
5
DecaDBEHIPS
+
Pyrolyzer Reformer(catalyst)
Char
Liquid
Gas
Residue
BrR
HR
HBr, SbBr3
catalyst
Pyrolysis Debromination
Liquid
recovered
Gas
GC-MS
XRD SEM
Raw plastics
Background Pyrolysis—Catalytic reforming process
6
Pyrolyzer
Reformer
Experimental conditions: Pyrolyzer:
Sample: Br-HIPS (5 g)
Tf : 450 C;
Heating rate: 10 C/min;
Reformer:
Catalyst: Fe/ZSM-5,Ni/ZSM-5,
Fe/MCM-41,Ni/MCM-41 (0.5 g)
T : 450 CN2 atmosphere
Experimental Schematic diagram of the experimental setup
7
Proximate analysis wt % Ultimate analysisa wt %Moisture 0.1 C 79.5Volatile matter 99.5 H 6.8Fixed carbon 0 N 0.1Ash 0.4 Ob 1.1
Br 7.8Sb 4.7
Characterization of the sample and catalystsTable1. The property of Br-HIPS
Catalyst HZSM-5 FZ NZ MCM-41 FM NM
Fe/Ni content (wt.%) 0 9.17 8.67 0 8.34 9.07
BET surface area (m2 g-1) 342.72 228.82 278.46 1091.98 810.86 848.12
Micropore area (m2 g-1) 242.62 190.30 201.55 36.03 - -
Micropore volume (cm3 g-1) 0.112 0.099 0.105 0.003 - -
Total pore volume (cm3 g-1) 0.189 0.150 0.184 0.958 0.584 0.633
Average pore size (nm) 2.21 2.62 2.64 3.51 2.88 2.98
Total acidity (mmol g-1) 0.746 0.727 1.008 0 0.062 0.281
Table2. The property of the catalysts
Results
8
XRD and SEM analysisa
1 µm
b
1 µm
c
2 µm
d
2 µm
agglomerated on the surfaceof parent HZSM-5.
dispersed in the porousstructure of the MCM-41
Results
9
NH3-TPD analysis
Figure 5 NH3 -TPD plots of the catalysts
Results
Weak and middle acid sites were detected in the parent HZSM-5.
New strong acid sites were created at 490 C in Ni/ZSM-5
The modified FM and NM catalysts exhibited weak acid sites.
10
Zeolites reduced the yield of oil product.
NZ promoted the gas product at the expense of liquid product.
Modified MCM-41 catalysts tended to convert the wax product into liquid oil.
Coke deposition increased in the Fe-modified catalysts.
Product distribution
Results
11
High content of 2 ring aromatics inthe oil.
Fe-modified catalysts slightlypromoted the single ring aromatics.
naphthalene and indene derivatives
styrene dimer and substitutedderivatives
Characterization of pyrolysis oil
Results
12
Single ring aromatics maintained ahigh feedstock recovery from Br-HIPS
Fe-catalysts promoted the productionof styrene.
FN and FM catalysts obtained the highrecovery of these selected compoundsup to 542.8 and 604.0 mg/g(plastic)
Characterization of pyrolysis oil
Results
13
2 µm
b
2 µm 2 µm
5 µm
a
c d
5 µm
e
2 µm
f
Sb/Br compounds
Weak peaks of Fe2O3/
NiO
NiSb
Sb/Br compounds
New peaks of NiO
NiSb/NiSb2O6
XRD patterns of the reacted catalysts
SEM images of the reacted catalysts(a)ZSM-5; (b) Fe/ZSM-5; (c) Ni/ZSM-5; (d) MCM-41; (e) Fe/MCM-41; (f) Fe/MCM-41
Characterization of spent catalysts
Results
14
Bromine Content in the Oils
76.74% of Br in Br-HIPS was transferred to the oils.
Modified catalysts reduced the bromine content in the oils
FM exhibited a better absorption ability of Br in the catalyst.
Results
HBrSbBr3
Organobromine
HBrSbBr3
Organobromine
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Possible catalytic reaction mechanism
1 Oligomerization
3 Cyclization
2 Carbanion mechanism
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2 3 3 2Fe O +6HBr FeBr +3H O
3 2 22FeBr 2FeBr +Br
Possible debromination mechanism
The modified catalysts of FZ and NZ significantly decreased theamount of oils with a corresponding increase in gas yield.
FM and NM tended to preserve the oil yield, exhibiting catalyticcracking performance in transforming the Br-HIPS sample into oil.
FZ and FM enhanced the depolymerization of Br-HIPS, withincreased formation of styrene monomer.
The Fe-catalysts intended to exhibit relatively higher debrominationefficiency than the Ni-catalysts, with high absorption abilities ofinorganic bromine.
17
Conclusion
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National Natural Science Foundation of China
( No. 51576073, 51376073)
Funds of Graduate Innovation and Entrepreneurship Program of HUST
(No.0118650043)
Acknowledgements
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