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

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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.

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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.

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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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