Synthesis and optimisation of the recovery route for residual products

Abstract The present work describes an optimisation model for the management of the recovery of residual products originated at industrial plants. The mSTN (maximal State Task Network) representation is used as the modelling framework for the general proposed network superstructure where all possible process transformations, storage, transports and auxiliary operations are accounted for. This is combined with the evaluation of a set of environmental impacts (EI), quantified by metrics (for air, water pollution, etc.) through the minimum environment impact analysis (MEIM) methodology and associated with waste generation at utility production and transportation levels. The final model is described as a MILP, which, once solved, is able to suggest the optimal processing and transport routes, while optimising a given objective function and meeting the design and environmental constraints. A motivating example based on the recovery of the sludge obtained from Aluminium surface finishing plants is explored. This aims at maximizing the quantity of sludge processed and reflects the trade-off between the cost for its disposal, processing, transport and storage, while accounting for the limits imposed in the environment pollutants associated.