Exergetic life-cycle analysis

Part III, "Case Studies" (Chapters 9 through 12), takes these illustrations a bit further, namely, by demonstrating the analysis for some of the most important processes in industry energy conversion, separations, and chemical conversion. Chapter 12 briefly discusses the concept of life cycle analysis, which aims to compare the consolidated inputs and outputs of a process or a product "from the cradle to the grave" [9], and its extension to include the minimization of process irreversibilities in a so-called exergetic life cycle analysis [10]. 

Chapters 9 through 12 demonstrate thermodynamic, or exergy analysis of industrial processes. First, Chapter 9 deals with the most common energy conversion processes. Then, Chapter 10 presents this analysis for an important industrial separation process, that of propane and propylene. Finally, Chapter 11 analyzes two industrial chemical processes the production of polyethylene. Chapter 12 is included to discuss life cycle analysis in particular its extension into exergetic life cycle analysis, which includes the "fate" or history of the quality of energy. 

One year before Ayres publications [7,8], Cornelissen [9] completed his PhD dissertation in which he had combined life cycle analysis with exergy analysis. He called this extension of LCA exergetic life cycle analysis. He explained that ELCA should be part of every LCA because the loss via dissipation of exergy is one of the most important parameters to properly assess a process and measure the depletion of natural resources. Cornelissen even went one step further and extended ELCA to what he called zero-emission ELCA. In this extension of ELCA, the exergy required for the abatement of emissions, that is, the removal and reuse of environmentally friendly storage of emissions, is accounted for. Cornelissen illustrated his ideas with examples of... 

Neelis, M., Kooi, H. van der, Geerlings, J. (2004). Exergetic life cycle analysis of hydrogen production and storage systems for automotive applications. Int.. Hydrogen Energy 29,537-545. 

Brehmer B, Struik PC, Sanders J. (2008). Using an energetic and exergetic life cycle analysis to assess the best applications of legumes within a biobased economy. Biomas Bioenerg, 32,1175-1186. 

Next, Cornelissen extended the LCA study to include the effect of depletion of natural resources making use of ELCA, the exergetic life cycle assessment. In this analysis a full mass and energy balance was made, that is, a first law analysis. Exergy values for all mass and energy streams were included in accordance with the Tables 6.1, 6.2, 6.3, 7.1, 7.2, 7.3 and 7.4 in Chapters 6 and 7. This analysis clearly showed where work was available in inputs and outputs and where it was lost. He could show that the cup scored less favorable than the mug in terms of depletion of natural resources (817 MJ vs. 442 MJ). 

Exergy analysis can be used to compare FP-FC systems with rechargeable batteries and combustion engines. Other important aspects, in addition to exergetic efficiency, are environmental impact, safety and life cycle cost. Efficient fuel utilization is particularly important for larger FP-FC systems. For small systems, the energy... 

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