Limited Life Cycle Analysis
There's more to chemical engineering than meets the eye...
An overview of LLCA
Limited Life-Cycle Analysis, LLCA, is a tool for quantitatively comparing solutions to environmental problems. It's applications in the chemical engineering field allow users to protect the environment by choosing the most environmentally-friendly option when designing a process. By breaking the process down into fundamental inputs and outputs, the impact of each option is determined and compared, yielding a comparatively optimal choice.
How to use LLCA
The process of LLCA consists of a few steps. First, define boundary conditions so that only the most important factors are considered. This greatly decreases the time and money needed to perform LLCA. Then create a list of the wastes produced and the resources consumed during each process. This includes local and remote contaminants to air, water, and soil, as well as any fuel or energy required. Then name a numerical Pollution Factor (PF) for each element of the list. This is a weighing factor that indicates the specific environmental impact of each element. This value can be based on legal limits, EPA guidelines, or other suggestions. The PF is expressed in Environmental Impact Units (EIU). Normalizing the pollution factors of each element to that of a single element, provides a basis for relative comparison. Finally, to compare the relative impact of one option to another, sum the PF's for each process.
History of LLCA
The environmental impact of chemical engineering processing became a premier issue during the 1960's and 1970's. At this time, the general public became more aware of the need to protect the environment. This led to the development of Life-Cycle Analysis, which gained wide-spread use throughout Europe, USA, and Japan by 1989. After years of research with LCA, a new, more concise approach, LLCA, was developed by Schaltegger and Sturm in 1996.
Looking to the Future
LLCA is currently being researched by both Ford and Volkswagon in attempts to create more environmentally friendly automobiles, considering production, use and eventual destruction of the vehical. This is becoming increasingly important due to the recent energy crisis.
LLCA is also being considered as a tool in implementing the new EPA limits. Since the EPA is now making different limits for air, water and soil pollution, LLCA can help make life simpler for the manufacturers. One thought is to use LLCA to create a holistic system to make the EPA limits more useful and standardized. Instead of having to worry about the effects of each individual system output, one can find the total effect of the system in Environmental Impact Units using LLCA and then stay within the limits for total environmental impact. This concept however is still in the brainstorming stage, so it remains to be seen what will become of it.
Examples of LLCA in practice can be found at the aiche website
A computer program demo of the extent of LCA can be found from
For further information contact:
Shannon Phillips and Lauren Raetz
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Last updated: May 2, 2001