The Use of Life Cycle Assessment with Crankcase Lubricants to Yield Maximum Environmental Benefit – Case Study of Residual Chlorine in Lubricant

Life Cycle Assessment (LCA) is a methodology used to determine quantitatively the environmental impacts of a range of options. The environmental community has used LCA to study all of the impacts of a product over its life cycle. This analysis can help to prevent instances where a greater degree of environmental harm results when changes are made to products based on consideration of impacts in only part of the life cycle.

This study applies the methodology to engine lubricants, and in particular chlorine limits in engine lubricant specifications. Concern that chlorine in lubricants might contribute to emissions from vehicle exhausts of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), collectively called PCDD/F, led to the introduction of chlorine limits in lubricant specifications. No direct evidence was available linking chlorine in lubricants to PCDD/F formation, but precautionary principles were used to set lubricant chlorine limits.

To complete this study, the LCA was supplemented by detailed emissions testing from the use and disposal phase of lubricants. Used in this way, it provides a model methodology to determine the optimal method of engine oil specifications to reduce total environmental impact. In the specific case of chlorine limits, the LCA and testing demonstrate that restricting chlorine does not (at least below 259 mgkg^-1- the highest level tested in the study) produce lower PCDD/F, and the higher energy costs and reduced frictional performance of low-chlorine dispersants can lead to greater overall environmental impacts.