Feedstock agnostic upcycling of industrial mixed plastic from shredder residue pragmatically through a composite approach

Shredding of a vehicle or an electrical and electronic equipment at its end-of-life (EOL) is a common practice to extract valuable critical raw materials. Unfortunately, this has the unintended consequence...


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. The process was modelled in Aspen Plus V10, using the RK-SOAVE thermodynamic property package, employing the Redlich-Kwong-Soave cubic equation of state-suitable for predicting the properties of hydrocarbon mixtures at high temperatures and pressures (ACS Sustainable Chem.Eng. 2023, 11, 3238-3247).The feedstock (25 o C, 1 bar), comprising a mixture of 50 wt% acrylonitrile butadiene styrene (ABS), 40 wt% polystyrene (PS) and 10 wt% polypropylene (PP), was mixed with saturated low pressure (LP) steam (6 bar) in a mass ratio of 1:1.5 (plastic: steam), and fed to a gasification unit operating at 800 o C and 1 bar.The gasification process was modelled using a Yield reactor (D-101) and a Gibbs reactor (GASIFIER), where synthesis gas (CO, H 2 , CO 2 , CH 4 , N 2 ) was produced from the chemical transformation of waste plastics.D-101 facilitates the decomposition of the plastics into C, H 2 and N 2 , utilizing mass balances guided by the feedstock elemental composition provided in Table S1, while the GASIFIER operates by predicting the mass flows of the synthesis gas based on Gibbs Free Energy minimization.The subsequent synthesis gas was combusted with excess air producing flue gas, which was routed to a combined cycle power generation unit comprising a Brayton cycle using a gas turbine (G-TR), and a Rankine cycle utilizing heat recovery steam generation (HRSG) -involving saturated/superheated steam heat exchangers (HX3/HX2 respectively) and two steam turbines operating at 100 bar (HP) and 6 bar (LP).The exhaust steam was condensed (COND1), pumped to 100 bar (BFWPUMP) and recycled to the HRSG unit.Additionally, heat was recovered from cooling hot effluent synthesis gas facilitating LP steam production (HX1) as well as integrating thermal heat from combustion (R-101) into gasification.Ultimately, the thermal efficiency of the process was estimated to be 44% (Table S2) -in alignment with common gasification processes (Energy Conversion and Management 2015, 105, 530-544).S4: Exemplary calculation to determine the mass of the f.u.
In this example, we used the mechanical properties of 40 wt.-%CF-reinforced mixed plastic as the model material.
In tension: Tensile yield strength = 31 MPa (   ) @ 0.14% In fracture: From section 3.5, K IC of 40 wt.-%CF-reinforced MP was found to be 2.61 MPa m 0.5 .Assuming the existence of a crack in an infinite plate and in the worst case scenario, the crack possesses the same dimension as the diameter of the CFs (7 μm), is calculated   as:

S1:1
Steam gasification of industrial mixed plastic from shredder residue 2 S2: Life-cycle inventory of processes considered in the LCA 4 S3: Mass of functional unit of PP, WF-reinforced, GF-reinforced and CF-reinforced residual mixed plastic (MP) with FEA and E-driven beam bending design 5 S4: Exemplary calculation to determine the mass of the f.u.6 S5: Mesh convergence of our chair model in Abaqus 7 Electronic Supplementary Material (ESI) for Green Chemistry.This journal is © The Royal Society of Chemistry 2023 S1: Steam gasification of industrial mixed plastic from shredder residue The process model (Fig. S1) gives an overview of a combined cycle power generation plant utilising waste plastics gasification.The model is developed and validated in accordance with the works from Saebea et al. (Energy Reports 2020 6, 202-207) and Salah et al. (ACS

Figure S1 :
Figure S1: Process flow diagram of waste plastics gasification and power generation.
Fig S3.Elastic fitting for tensile yield strength

Table S1 :
Chemical characterisation of industrial mixed plastic from shredder residue for use in the process model in Fig.S1.Ash, moisture and sulphur composition was assumed to be negligible for this study.

Table S2 :
Power generation system inventory normalised to 1 kg of industrial mixed plastic from shredder residue.