Hierarchical Integration of Planning and Scheduling for Industrial Waste Incineration

Abstract

This works aims to demonstrate that hierarchical integration of planning and scheduling of industrial waste incineration improves the energy efficiency of the process, compared to available scheduling approaches. Through the integration with planning models, scheduling models can rely on more far-sighted information; therefore, energy deficits and excesses can be better compensated in the long run. Subsequently, the auxiliary fuel consumption of the incineration process can be further reduced, which leads to an overall increase of the energy efficiency. Planning and scheduling models are formulated as mixed-integer linear programming (MILP) problems with discrete time representation, based on single, uniform grids. The considered waste incineration system consists of storage tanks, a complex piping network, tank wagons for waste transport, unloading stations, and firing lances of incineration units. The conducted industrial case studies reveal substantial improvement potential of daily empirically based waste incineration routines and show that systematic integration of planning and scheduling outperforms consecutive stand-alone scheduling of industrial waste incineration both economically and environmentally by reducing auxiliary fuel usage and CO 2 emissions per ton of waste treated, by 16% and 1%, respectively.

Optimal Design and Management of Industrial Waste-to-Energy Systems

“…,max (11) From the described external tanks, trucks, wagons, and regions, waste can be shipped to internal tanks, incineration units or, in the case of external tanks and regions, outside the system. Internal tanks are located at incineration facilities and are used for temporary storage, buffering, and mixing different waste streams w before these are incinerated.…”

“…The investigated waste-to-energy system is modeled as a mixed-integer linear problem (MILP) with discrete time representation, as successfully introduced in previous studies on the optimization of industrial waste incineration. , The developed multiperiod model is written with a modular formulation, such that it can be applied to both single-site systems and multisite networks. Moreover, it is easily adaptable to different time resolutions by changing the affected parameters accordingly, in order to achieve the desired result precision.…”

“…Auxiliary fuels, such as natural gas and water are used in case of energy shortage and excess, respectively. In this sense, recent studies have shown that an optimized planning and scheduling of hazardous waste incineration can be an efficient tool to reduce the consumption of such auxiliary fuels, with important economic and environmental benefits. , The model proposed by Abaecherli et al , optimizes waste flows between different storage and treatment units, while imposing relevant operational constraints on waste mixing, treated capacity and combustion temperature under an auxiliary fuel minimization objective.…”