Alternate performance metrics, impact

Thus far, we have focused on alternate performance metrics and associated supply chain architecture. Now we will consider the impact of competitors who independently make decisions to maximize their performance. The presence of competitors may often benefit individual customers but may also decrease the profitability of supply chain entities. A key concept is that competing supply chains generate equilibrium results, in which each supply chain makes decisions independently, anticipating but not knowing decisions by competitors. There are several ways that supply chains affect the competing choices and performance of a given supply chain. 

The aim of this case study is to illustrate the environmental impact assessment through a life cycle approach of HgnoceUulosic biorefineries, which are representative examples of multifunctional systems comprising various production lines. This example highlights the need to provide environmental performance metrics by allocating the total bio-refinery impacts to the biorefinery final products. This kind of allocation is particularly useful when a certain final product of interest can also be produced by alternative ways (i.e., other biomass- and fossil-based pathways) and, therefore, a comparison between these alternatives for the functional unit of 1 kg of product is required. In other words, in this case the focus is not on the utilization of 1 kg of biomass where the total biorefinery environmental performance would be of interest, but on a specific production path within the biorefinery production network, considering of course the joint or coproduction nature of the system. This allocation procedure (here the term allocation is... 

It should be understood that to develop process metrics based on a credible risk assessment will require a considerable number of tests to assess appropriately the potential environmental hazards associated with the process and the materials used in the process. One typically needs to screen compounds to assess their environmental hazard and their tendency for persistence, bioaccumulation, and toxicity. Depending on how a compound is ultimately used, environmental testing might lead you to the conclusion that it is best to avoid the commercial production of a particular compound. Alternatively, you might devise a process that uses the compound but controls the environmental risk to acceptable levels. For the latter case, performing a process-specific risk assessment would be imperative to assess the impact of the inherent hazard and environmental fate and effects of a given chemical or set of chemicals. In addition, the unique characteristics of the process, available treatment, and volumes will need to be taken into consideration. 

In principle, aU these aspects related with the solvent selection will have an impact on the outcome of the LCA metrics of the various alternatives. Fig. 13.2 presents a generic flowsheet for the solvent-based postcombustion CO2 capture processes, illustrating also the main concerns from an LCA point of view. If the LCA scope is to screen solvents for postcombustion CO2 capture without performing process simulations (i.e., in a very early phase of process design, where perhaps the number of solvent molecules to be screened is immense, for instance, in computer-aided molecular design [CAMD] of solvent molecules [68]), the potential solvents should be characterized based on properties that would indicate their expected performance in the capture process (e.g., the standard flowsheet of Fig. 13.2). These properties can be thermodynamic in nature (e.g., solubility parameters between CO2 and the solvent, solvent heat of vaporization. 

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