Exploring the potential of resource-recovery from plastic waste in New-Zealand Elsa Dhombres1 , Oseweuba Valentine Okoro2 , Zhifa Sun2∗ 1EPF Graduate school of Engineering 2Department of Physics, Otago University , *Email address: zhifa.sun@otago.ac.nz; Phone: 64 3 479 7812 1 Contents • Activities undertaken in the last weeks • Results obtained • Conclusion 2 Activities undertaken in the last weeks 3 Characterisation of the HTL-oil via elemental analysis. Estimating the molecular formula of the HTL-oil. Estimation of the mass of CO2 produced by burning 1kg of plastic as justification for the un-favourability of incineration as a waste management strategy. Higher Heating Value (HHV) estimation of the HTLoil. Identification of major chemical species present in the oil via Gas Chromatograph–Mass Spectrometry (GCMS) and Nuclear Magnetic Resonance (NMR). 4 Results obtained 5 Characterisation of the HTL oil via elemental analysis: Exp. run C H N S O wt. % wt. % wt. % wt. % wt.% Initial 82.60 13.64 Trace Trace 3.76 Second 83.48 14.09 Trace Trace 2.43 The mean mass percentage of oxygen, carbon, hydrogen, is therefore determined to be 3.1 wt. %, 83.04 wt.% and 13.9 wt. % respectively. 6 Molecular formula estimation of the HTL-oil • Molecular formula of the HTL-oil : 𝐶𝐻2 37𝑛 𝑂 • The feedstock was 𝐶𝐻2 1261𝑛 𝑂 + 𝐴𝑠ℎ The HTL-oil is ash free. The mean carbon and hydrogen content of HTL-oil of 83.04 wt. % and 13.9 wt. % is similar to the mean carbon and hydrogen content of fossil crude of 84 wt % and 14 wt. % 7 Estimation of the mass of CO2 produced from plastic incineration Mass of CO2 produced by burning plastic: 𝑦 [𝐶𝑥 𝐻𝑦 ]𝑛 + 𝑛 𝑥 + × 𝑂2 + 3.76𝑁2 + 𝐴𝑠ℎ 4 𝑛𝑦 𝑦 → 𝑛𝑥𝐶𝑂2 + 𝐻2 𝑂 + 𝑛 𝑥 + 3.76 × 𝑁2 + 𝐴𝑠ℎ 2 4 Considering that the molar mass of CH2 and CO2 are 14g/mol and 44g/mol respectively, burning 1kg of plastic would produce 3.1 kg of CO2, therefore based on the estimated mass of waste plastic generated per year (275 million metric tons) an additional 852.5 million tons of CO2 will be introduced to the atmosphere annually. 8 HHV estimation of the HTL-oil The HHV of the HTL-oil was estimated using the equation: 𝐻𝐻𝑉𝐻𝑇𝐿−𝑜𝑖𝑙 %𝑂 = 0.338 %C + 1.28 %H − + 0.095 %𝑆 8 = 47.90 ± 0.41 MJ/kg The HHV of the HTL–oil is higher than the HHV of the plastics and similar to the HHV of fossil crude of 47 MJ/kg. 9 NMR analysis The protons detected via NMR are largely from compounds with alkyl and alkene functional groups. 100 GC-MS analysis The main compound was found to be largely long chain alkanes representing about a mole fraction of 0.75 of the HTL-oil mixture. Name: Heptacosane Formula: 𝐶27 𝐻56 These n-alkanes can be recovered via High-performance liquid chromatography separation. 91 100 O O 50 55 100 69 83 O O 108 55 207 125 147 179 282 0 50 100 150 200 250 300 350 (mainlib) 9-Octadecenoic acid (Z)-, phenylmethyl ester 50 81 67 99 111 141 167 198 226 268 0 50 100 150 200 250 (mainlib) 7-Methyl-Z-tetradecen-1-ol acetate 300 350 111