Development of Chemical Process Design and Control for Sustainability

Abstract

This contribution describes a novel process systems engineering framework that couples advanced control with sustainability evaluation for the optimization of process operations to minimize environmental impacts associated with products, materials and energy. The implemented control strategy combines a biologically-inspired method with optimal control concepts for finding more sustainable operating trajectories. The sustainability assessment of process operating points is carried out by using the U.S. EPA's Gauging Reaction Effectiveness for the ENvironmental Sustainability of Chemistries with a multi-Objective Process Evaluator (GREENSCOPE) tool that provides scores for the selected indicators in the economic, material efficiency, environmental and energy areas. The indicator scores describe process performance on a sustainability measurement scale, effectively determining which operating point is more sustainable if there are more than several steady states for one specific product manufacturing. Through comparisons between a representative benchmark and the optimal steady states obtained through the implementation of the proposed controller, a systematic decision can be made in terms of whether the implementation of the controller is moving the process towards a more sustainable operation. The effectiveness of the proposed framework is illustrated through a case study of a continuous fermentation process for fuel production, whose material and energy time variation models are characterized by multiple steady states and oscillatory conditions.

Development of Biomimetic-Based Controller Design Methods for Advanced Energy Systems

“…This analysis also shows that the steady-state concentration of product, , varies significantly with . In addition, the oscillatory behavior that arises from the interaction between cell growth, substrate consumption, and the ethanol production portrayed in Figure 3.4 is in agreement with the literature [46,47,49]. The potential existence of multiple steady states and the oscillations are undesirable in terms of system's performance and stability.…”

“…Biomass plays the role of catalyst for substrate conversion and is also a product of the fermentation process, while the substrate is a solution of glucose for feeding the microorganisms. Moreover, ethanol is the desired product of the process and also an inhibitor for the enzymatic reactions [46,47]. implementation of such optimal controller for this fermentation process is a challenging task, mainly due to these highly nonlinear dynamics and the constraints imposed on the process variables.…”

“…In the given indirect inhibition structural model, the concentration of the key component is affected by both substrate and product concentrations. In particular, the key component formation is inhibited by the product concentration and is also a function of substrate concentration [46,47]. In this case, the small values of 0 and 0 in the inlet concentrations are considered for the purpose of initializing the simulations.…”

Case Study about the Energy Absorption Capacity of Metal Oxide Varistors with Thermal Coupling

“…This would be lost through progressive dissipation in the colder environment only in the event of disconnection of the equipment from the grid. The value of this latent heat represents only a fraction of the value of the electric energy that turns into heat inside the varistor, through the effect of Joule-Lenz in the event of a surge wave [7].…”

Realizing Energy Savings in Integrated Process Planning and Scheduling

“…Nevertheless, with a rapidly deteriorating global climate and the urgency of energy efficiency and carbon emission reduction requirements [17], environmental friendliness, which has never been a major concern in existing research on the IPPS problem, should be considered to be a serious topic [18,19]. The absence of sustainable practices will lead to negative impacts on the environment and society [20,21]. Although there are many approaches to realize energy savings in manufacturing processes, energy-effective scheduling is a very effective way with no capital investment to reduce energy consumption in manufacturing processes.…”