Machine learning-based discrete element reaction model for predicting the dechlorination of poly (vinyl chloride) in NaOH/ethylene glycol solvent with ball milling

Neural network based prediction of the efficacy of ball milling to separate cable waste materials

“…The simultaneous training with multiple series of datasets can facilitate the model to learn general parameters applicable to different series 63 . However, there is a phenomenon that the model is overfitted based on data from the later period 37 . Thus, the asynchronous training with multiple timesteps can mitigate the overfitting issue, which can be proven by validating the trained model with fewer timestep numbers shown in Figs.…”

“…Furthermore, a new dimension representing the calculation timestep (d t [s]) is created for Y sep of each dataset. Asynchronous timesteps are introduced because the model training will overfit the experimental results at the end of treatment based on our previous study 37 . With the dimension of d t , the parameters can be optimised to balance the prediction errors for the entire dynamic process.…”

“…With a three-dimensional (feature, dataset, and timestep) input tensor ( Input ), artificial neural networks are defined to predict a new Y sep with the advance of treatment time ( t , [s]). In our previous ML modelling to predict a dechlorination reaction of PVC waste by ball milling 37 , the output of each timestep was calculated by a pre-defined function based on the process mechanism 46 . However, for the cable separation by ball milling, only a qualitative mechanism was available 20 .…”

“…Existing studies modelled cable separation processes as polynomial 35 or support vector regression 36 ; however, none of these works carry out dynamic modelling of the process, which is innovatively realised by recurrent neural network (RNN) in this study. Previously, we have developed an RNN model combined with the chemical reaction mechanism for predicting the dechlorination degree of PVC in ethylene glycol/NaOH solvent 37 . However, the separation of PVC and Cu from cable waste is a physical process that requires a more general modelling framework for predicting the dynamic behaviour without chemical kinetics.…”

Synergistic effect of polyvinyl chloride and coal ash on thermal separation of heavy metals from MSWI fly ash through molten salt process

“…PVC waste could also be converted into coal-alternative fuels or adsorbent through hydrothermal treatment (Huang et al, 2019;Lu et al, 2020b;Xu et al, 2021). A Cl recovery process is dechlorination of PVC by ball milling (Lu et al, 2019(Lu et al, , 2020a. Due to the large amount of chlorine (Cl) in PVC, HCl gas is produced during thermal treatment, which would cause the corrosion of treatment facilities (Kumagai et al, 2017;Torres et al, 2020).…”