Life-cycle inventory methods

Hirsinger, F. (1998) Comparing oleochemical and petrochemical surfactants with the life cycle inventory method (LCI). Chim. Oggi, 16 (10), 62-66. 

The production of the agrochemical 6 (Scheme 5.7) is carried out batchwise via a three-step protocol. Mass balancing has been conducted for three stages of development Laboratory-, pilot- and operation scale. An LCA was available for the operation stage only. A description of this LCA including data sources and data acquisition methods was published by Geisler et al. (product A in reference [9] corresponds to product 6 here). Many parameters in the Life-Cycle Inventory (LCI) are estimated, especially utihty demands and yields of processes for the production of precursors. Uncertainty in these estimations was illustrated in a... 

The core of LCA is a cradle-to-grave life-cycle inventory analysis that is fundamentally an engineering exercise describing a chemical, material, and energy accounting balance for the entire product system. The various inputs and outputs are collected or inventoried for each unit operation in the defined system (see fig. 4.4). A key qualifier in the figure is the definition of the system boundary, as it will directly affect the quality of the final results and conclusions. The inventory practice and methods are relatively well defined. 

Frischknecht R, Jungbluth N, Althaus H-J, Bauer C, Doka G, Dones R, et al. Implementation of life cycle impact assessment methods. Ecoinvent report No. 3, v2.0. Dubendorf Swiss Centre for Life Cycle Inventories 2007. 

Life-cycle assessment methodology has been used since the 1960s with early studies that focused solely on energy usage and solid waste issues. This focus continued in life-cycle assessments performed during the oil crisis in the 1970s.86>87 The unique aspect of all of these initial studies was the early development and use of life-cycle data inventories with less emphasis on environmental risk impacts of the associated processes studied. A method published by the Royal Commission on Environmental Pollution in 1988, employing the Best Practicable Environmental... 

The inventory data and the classified and characterized results are the ecological profile of the product or product system under study. These profiles may be used as modules for the life cycle assessment of subsequent products, for which these products are input of goods (e.g. LCl data of a steel production analysis are the basis for an LCA of a car made of tailored blanks such as building material profiles, for example, may be used to analyze buildings). A prerequisite for this is however that the methods and background data used for the modeling of the systems are identical. 

Let us pause and take an inventory of the situation up to this point. (1) We have a plausible mechanism of modulation of both components of WF of a selective layer (palladium) and (2) we have at least two methods of measurement of this effect, the macroscopic Kelvin probe and a field-effect transistor. However, the placement of the selective layer within the structure used for either measurement determines whether the effect is observable. In order to explain this caveat, we add another layer of the same metal M between Pd and the insulator in the structure shown in Fig. 6.33. This would correspond to the real life situation when we would try to connect a selective layer by a wire to the IGFET or a Kelvin Probe. It is not necessary to perform the same cycle as we did in Fig. 6.33. Instead, we add the individual energy contributions in the cycle, which begins and ends at the silicon Fermi level (moving again anticlockwise) ... 

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