Plastics World Plastics Production 299 Million Tonnes/year EU - PowerPoint PPT Presentation

FLEXI-PYROCAT T Pyrolysis-Catalysis of Waste Plastics to Fuels, Chemicals & Materials Research and Innovation Staff Exchange Project, Grant number: 643322-FLEXI-PYROCAT; as part of the Marie Sklodowska-Curie Action: H2020; H2020-MSCA-RISE-2014 Paul T. Williams University of Leeds, Leeds, UK

Plastics  World Plastics Production 299 Million Tonnes/year  EU Plastics Production 57 Million Tonnes/year Source : Plastics the Facts 2014/2015, Plastics Europe 2015

Life Cycle of Plastics European Plastics Life Cycle Energy Recycling Recovery 6.6 8.9 Mtonne Mtonne Export Export Export Recovery 15.6 Mtonne EU-27 Converter Plastics Post-consumer Consumer demand Production plastics waste demand 45.9 25.2 57 Mtonne Mtonne Mtonne Disposal 9.6 Mtonne Import Import Import Source : Plastics Europe 2014

Waste Plastics Trade Global map of export Global map of import transactions in waste plastics transactions in waste plastics (2011) (2011) Annual volume of globally traded waste plastics is ~15 Million tonnes Source: Velis, C., Global recycling markets - plastic waste: A story for one player - China . ISWA, International Solid Waste Association: Vienna, 2014

China: Waste Plastics  56 wt.% of Global imports of waste plastics end up in China  87 wt.% of EU exports of waste plastics end up in China  45 wt.% of EU waste plastics collected for recycling also ends up in China Weight Contribution 1,000 Tonnes (%) Hong Kong 1,984 24.7 Thailand 802 10.0 Sources of waste Japan 737 9.2 plastics imported Germany 669 8.3 into China Philippines 455 5.7 USA 426 5.3 Others 2,972 36.9 Total 8,042 100 Source: Velis, C., Global recycling markets - plastic waste: A story for one player - China . ISWA, International Solid Waste Association: Vienna, 2014

Waste Plastics in the EU EU Waste Plastics: 25.2 Million Tonnes/year “European Strategy on Plastic Waste in the Environment” Members of the European Parliament noted;  “illegal dumping, illegal exports and improper storage, had led to significant global damage to human health and the environment”  “insufficient internal demand for recycled materials”  “increased exports of waste plastics, resulting in loss of materials and employment in the EU.” Source:2013/2113(INI) – 14/01/2014 Text adopted by EU Parliament

Process Conditions Two-stage pyrolysis-catalysis of waste plastics; Waste Plastics • Facilitates decreased plastic viscosity, reducing mass transfer and heat transfer problems in the subsequent catalysis • Process is more controllable e.g. the temperature of each stage Thermal can be easily controlled. Reactor • Greater control of the catalytic process conditions Catalytic • Mixed plastic wastes : any residues and dirt associated with the Reactor plastics remains in the pyrolysis unit. • Improves contact between pyrolysis products and the catalyst High Value and enables the reacted catalysts to be recycled and reused. Products Hydrogen Carbon nanotubes Gasoline & chemicals Source: Serrano D.P., et al. ACS Catalysis, 2, 1924-1941, 2012.

Catalysts are KEY Waste Plastics Two-stage processing with Pyrolysis Reactor catalysts for higher value Catalytic Reactor products Reforming Catalysts Solid Acid Catalysts High Value Products High Value Products Carbon Hydrogen Gasoline Chemicals nanotubes Depending on the type of catalyst used and the process conditions, high value products can be targeted. For example, the hydrocarbon pyrolysis products derived from the waste plastics can be steam reformed in the second stage catalytic reactor with nickel based catalysts at typical catalyst temperatures of ~800 °C to produce a hydrogen rich syngas. Alternatively, solid acid catalysts such as microporous Zeolites and mesoporous MCM-41 can be used in the second stage catalytic reactor at temperatures of ~500 °C to produce an upgraded oil product for use as premium grade fuels or chemicals.

Contents Thermochemical Conversion of Waste Plastics to Fuels, Chemicals & Materials 1. Hydrogen 2. Carbon nanotubes Waste Plastics 3. Gasoline & Chemicals

1. Hydrogen Thermochemical Conversion of Waste Plastics to Fuels, Chemicals & Materials 1. Hydrogen 2. Carbon nanotubes Waste Plastics 3. Gasoline & Chemicals

Catalytic methane steam reforming World H 2 production ~50 Mt/yr Steam-methane reforming reaction CH 4 + H 2 O → CO + 3H 2 Water-gas shift reaction CO + H 2 O → CO 2 + H 2 Commercial catalytic methane steam reforming Hydrogen is currently produced mostly (96%) from fossil fuels, the largest source being natural gas (methane). The process involves steam reforming of methane in the presence of nickel catalysts at temperatures ~ 800 °C to produce hydrogen and carbon monoxide. Further reaction of the carbon monoxide with steam using an iron oxide catalyst at ~350 °C produces enhanced hydrogen yields, but also carbon dioxide via the water gas shift reaction. Source: http://www.digipac.ca/chemical/; http://www.airproducts.com

Catalytic steam reforming of waste plastics pyrolysis gases Waste plastics catalytic steam reforming Reactions taking place during pyrolysis-catalytic steam reforming of waste plastics Plastic Pyrolysis wastes Reactor 500 °C Steam Catalyst Reforming/ Gasification Reactor 800 °C Producing hydrogen from waste plastics would offer an alternative feedstock and also Hydrogen solve a major waste treatment problem. rich gas

Cerznik & French 2006  0.34 g H 2 g -1 polypropylene  80% of the maximum H 2 potential amount (0.429 g H 2 g -1 polypropylene (i.e. if all of the polypropylene was completely converted to CO 2 and H 2 )  Gas composition ~70 vol.% Pyrolysis-Catalytic Steam Reforming of waste plastics H 2 , ~16 vol.% CO 2 , ~11 Commercial C11-NK nickel catalyst vol.% CO Pyrolysis 650 °C & catalytic steam reforming 850 °C Source: Czernik S., French R.J., (2006) Energy & Fuels, 20, 754-758.

Catalyst type a: Ni-Al (1:4) i: Ni-Al (1:4) b: Ni-Al (1:2) j: Ni-Al (1:1) 70 c: Ni-Al (1:1) 65 k: Ni-Al-Mg (1:1:4) Potential Hydrogen Production (%) 60 d: Ni-Mg-Al (1:4:1) l: Ni-Mg-Al (1:1:1) 55 e: Ni-Mg-Al (1:1:2) Potential H 2 production (wt.%) 50 f: Ni-Mg-Al (1:1:1) (i-l are calcined at 850 °C) 45 g: Ni-Cu-Al (1:1:2) 40 h: Ni-Cu-Mg-Al (1:1:1:3) 35 30 (a-h are calcined at 750 °C) 25 20 Type of catalyst and catalyst preparation 15 procedure influence catalyst activity and 10 therefore H 2 production 5 0 a b c d e f g h i j k l a b h l c d e f g i j k • Increased Ni content: increased H 2 potential Catalyst Catalyst • Syngas: H 2 67 vol.%, 24 vol.% CO • Mg: no influence on H 2 Potential H 2 production from pyrolysis- • Cu: negative influence on H 2 gasification of polypropylene with different catalysts • High calcination temperature: negative influence on H 2 Source: Wu C., Williams P.T. (2009) Applied Catalysis B: Environmental, 90, 147-156.

Influence of process parameters 70 60 70 Ni-Al Ni-Mg-Al Potential H 2 production (%) 60 Steam Potential H 2 production (%) Catalyst Potential Hydrogen Production (%) 50 Ni/CeO 2 /Al 2 O 3 60 Potential H 2 production (Wt.%) Ni/ZSM-5 input Gas composition (Vol.%) 50 support 50 40 CO H 2 40 40 Ni/Al 2 O 3 Ni/CeO 2 30 CO 2 30 CH 4 30 C 2 -C 4 20 20 20 Ni/MgO 10 10 10 0 0 Catalyst 0 2 4 6 8 10 12 14 16 Catalyst -1 ) Water flow rate (g h Polypropylene Potential H 2 production (%) Gas composition (vol.%) • Type of support and catalyst Catalyst preparation influence H 2 yield temperature • Steam input reaches an optimum followed by saturation • Catalyst temperature influences H 2 yield; but can sinter the catalyst Catalyst Temperature (°C) Source: Wu C. and Williams P.T. (2009), Applied Catalysis B: Environmental, 87, 152-161.; Wu C, Williams P.T. (2009) Energy & Fuels, 23, 5055-5061; Wu C. Williams P.T. (2008) Energy & Fuels, 22, 4125-4132.

Influence of type of plastic 70 CO Gas composition (vol.%) H 2 65 CO 2 60 H 2 production (g/g plastic) CH 4 55 C 2 -C 4 Gas composition (vol.%) 50 Gas composition (Vol.%) 45 40 35 30 25 20 15 Catalyst Temperature (°C) 10 5 Post-consumer waste plastics 0 PP PS HDPE Waste Plastic Mixed Plastics Waste Mixed PS HDPE PP plastic plastic 70 65 Plastic type 60 Gas concentration (Vol.%) 55 50 H 2 Effect of extended 45 CO 40 CO 2 continuous reaction time 35 30 Screw Kiln 25 20 15 10 0 1 2 3 4 5 6 7 8 9 Reaction Time (h) Wu C, Williams P.T., (2010), Int. J. Hydrogen Energy, 35, 949-957 Wu C., Williams P.T. (2010) Fuel, 89, 3022-3032.

Tokyo Institute of Technology, Japan Polypropylene • 5%Ru/γ -Al 2 O 3 catalyst • 630 °C catalyst temperature • 98.3 wt.% gas yield • 170.8 mmol H 2 /g PP • Syngas: 71 vol.% H 2 Polystyrene • 5%Ru/γ -Al 2 O 3 catalyst • 630 °C catalyst temperature • 96 wt.% gas yield • 165.1 mmol H 2 /g PS • Syngas: 68 vol.% H 2 Source: Park Y., et al. (2010) Fuel Processing Technology, 91, 951-957. Namioka T., et al. Applied Energy, 88, 2019-2026, 2011.