Life cycle analysis of gas to liquids (GTL) derived linear alkyl benzene

The production of normal paraffin from the Gas to Liquids (GTL) process is of relevance to the detergents industry. The environmental benefits of GTL derived Linear Alkyl Benzene (LAB) production relative to petroleum derived LAB production can be demonstrated by a rigorous comparison of the lifecycle impacts of both pathways. Using current industrial knowledge and consistent Life Cycle Assessment (LCA) methodological choices, we estimated life-cycle cradle-to-gate environmental impacts, including greenhouse gas (GHG) emissions, of LAB production from petroleum-derived crude oil and natural gas, respectively. In addition, we developed sensitivity cases to assess the robustness of the results due to the uncertainty or variability of key parameters in both pathways. Our base case results show that the lifecycle cradle-to-gate GHG emissions of GTL LAB production are 20% lower than conventional LAB production. Compared to conventional LAB production, lifecycle GHG emissions of GTL LAB are consistently lower, regardless of which allocation method is applied. Despite this, cradle-to-gate GHG emissions of GTL LAB are highly sensitive to assumptions associated with upstream natural gas venting and flaring emissions. Other environmental impacts for the GTL LAB pathway also appear to be favorable when compared to conventional LAB production. This can be rationalized by the GTL LAB route achieving (a) reductions in fired-duty emissions associated with the avoided prefractionation/Molex™ step and (b) avoided fired-duty emissions associated with the normal paraffin coproduct displacing kerosene-derived paraffin production. These results are broadly consistent with previous studies that demonstrate high-quality GTL coproducts affording a net GHG emissions avoidance when displacing conventional, crude oil derived analogs.