-Environmental impact assessment is becoming indispensable for the design and operation of chemical plants. Structured and consistent methods for this purpose have experienced a rapid development. The more rigorous and sophisticated these methods become, the greater is the demand for convenient tools. On the other hand, despite the incredible advances in process simulators, some aspects have still not been sufficiently covered. To date, applications of these programs to quantify environmental impacts have been restricted to straightforward examples of steady-state processes. In this work, a life-cycle assessment implementation with the aim of process design will be described, with a brief discussion of a dynamic simulation for analysis of transient state operations, such as process start-up. A case study shows the importance of this analysis in making possible operation at a high performance level with reduced risks to the environment.

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This paper provides an uncertainty analysis for efficiency gains in internal combustion engines generated by cycling between two operating points. The uncertainties are due to incomplete knowledge of the bsfc field of the engine. In the case of bio fuels, these uncertainties can be fairly large and exact bsfc curves are rarely available. The proposed concept provides a graphical method for determining whether cycling provides efficiency advantages despite the presence of uncertainties. If cycling is beneficial for efficiency, the introduced concept provides the power range those results in efficiency advantages. The proposed method is based on a graphical evaluation in the engine bsfc field, with uncertainties being represented by a bsfc envelope. The decision making criterion is based on the bsfc envelope and its relationship to the cycling induced bsfc curve.

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