A New LCA Methodology of Technology Evolution (TE-LCA) and its Application to the Production of Ammonia (1950-2000) (8 pp)

Goal, Scope and Background

This paper presents a new LCA method of technology evolution (TE-LCA), and its application to the production of ammonia, the second largest chemical product in the world, over the last fifty years. The TE-LCA of a chemical process is the procedure in which historical information on a process, mainly the evolution of technical parameters, is translated by simulation to mass and energy balances as a function of time. These mass and energy balances are then transformed into environmental impact indicators using common LCA approaches. Finally, the evolution of environmental impact resulting from the investigated process can be related to its technical and other, i.e. legislative, developments.

Methods

The technological evolution of the production of ammonia was compiled according to three basic sources of information: patents, publications and industry data. From these sources in a first step, the major technological advances of the process were identified as a function of time delivering different process variants that were modelled using the simulation software Aspen Plus®. In a second step, the evolution of environmental regulations is studied. For those energy related emissions that were regulated, e.g. SOx and NOx, it was assumed that threshold values defined in legislation were realized immediately. The aggregation of both steps allows the calculation of the emissions resulting from the production (cradle to gate view) of the investigated chemical as a function of time.

Results and Discussion

The application of the TE-LCA to the production of ammonia revealed when and to which extent technological and legislative developments resulted in the reduction of energy related emissions in the production of this chemical compound. Overall, the reduction of emissions from ammonia production was highly influenced by the technological development and only to a lower extent by environmental regulations.

Conclusion

The results obtained from the TE-LCA method is useful to reveal how the environmental performance of a process developed in the past and to identify the reasons for this development. The investigated case study of ammonia production shows that investment in technological development also paid off in terms of being ahead of tightened environmental legislation that might bear potential cost consequences such as carbon dioxide tax.

Outlook

The presented method can be easily extended by including an economic analysis, which provides additional information on why certain technological developments were enforced and which the economic consequences of changes in environmental legislation were. The new methodology has to be applied to additional case studies, i.e. to other chemical sectors than basic chemicals and to other branches than chemicals. In other chemical sectors, toxic emissions from the production process might have to be considered and trade-offs between these and the overall energy consumption might result.