Introducing Quantitative Life Cycle Analysis into the Chemical Engineering Curriculum
The concept of “sustainability” can have a range of meanings depending upon the stakeholder. The challenge for chemical engineers, with their knowledge of processes and their interaction with the environment, is to provide objective input into overall judgement of what is sustainable practice.
In chemical engineering a range of approaches are applied in development and impact assessment of industrial processes. For example, life cycle analysis is used to quantify the impact of a product or process over its entire (cradle-to-grave) lifetime. Green engineering focuses largely on inputs, and alternative pathways, to minimise the usage and generation of harmful components. Finally, systems thinking takes a holistic approach to address not only the question of how we can do things better, but does society really need the product or process in the first place. The challenge for chemical engineering educators is to introduce the abovementioned concepts which integrate with the traditional framework of mathematical and scientific skills.
This paper describes a number of quantitative examples whereby the principles and methodologies of life cycle analysis are introduced at the very beginning of the chemical engineering program. The examples are staged in their complexity. Firstly, they describe the process by which a cradle-to-grave analysis is carried out, based on applying intuitive material and energy balances to determine outputs and impact assessment. Secondly, the basic models are then extended to be used as a tool for optimisation (minimisation) of impacts at both local and global scales.