Abstract
Chemical engineers however need quick and reliable cradle-to-grave evaluations, conforming to the ISO norm 14040, already at the design stage in order to assess the ecological performance of their design compared to design alternatives as well as to identify ecological hotspots in order to decrease the ecological impact of the process in question.
The Sustainable Process Index methodology has been particularly developed for this purpose and has been widely applied to the measurement of the ecological performance in production systems. Ecological performance is expressed in aggregate form as Ecological Footprint per service unit, thus allowing the engineer to take decisions. De-aggregation into different environmental pressure categories that this methodology allows as well helps the engineer to understand, what causes the engineer to pinpoint the process steps that are critical to the overallperformance of the ecological pressure in a certain process step. For the modelling of these problems the software tool SPIonExcel has been in use in the last decade.
SPIonWeb is a web browser based software tool substituting SPIonExcel, which allows to model industrial processes on a thoroughly revised data base and a still more encompassing methodological base. Basic processes like electricity, transport, base chemical production chains are provided in a life cycle based database. Dynamic modelling allows creating process loops which allows simulating changes in the final product ecological performance if sub-process modification are assumed. Besides the Ecological Footprint (calculated with the SPI method) theprogram also features process visualization, detailed material balance for inputs and emissions, CO2 and GWP life cycle emissions.
The paper provides examples of ecological process evaluation for different chemical engineering applications, in particular processes providing energy from different renewable sources and bio-chemical processes, e-g. bio-plastic production. Analysing these thoroughly different process chains will be used to highlight the information that can be gleaned from ecological process evaluation during chemical engineering design.