Life cycle assessment of low-temperature thermal desorption-based technologies for drill cuttings treatment.

ABSTRACT

The life cycle impacts of treatment of typical oil-based drill cuttings (OBDCs) using three low-temperature thermal desorption (LTTD)-based systems, including thermomechanical cuttings cleaner (TCC), screw-type dryer (STD), and rotary drum dryer (RDD), were explored with a case study in British Columbia, Canada. Two energy supply scenarios, including diesel generator-based onsite (scenario i) and hydropower-based offsite (scenario ii) treatments, were considered in the assessment. The results show that RDD generated the lowest life cycle impacts in terms of damages to human health, ecosystems, and resources in scenario i. TCC-scenario ii generated the lowest impacts among all assessed cases, suggesting that using renewable energy can greatly reduce the impacts of LTTD-based OBDCs treatment. Also, net environmental benefits could be achieved considering the reuse of recovered oil, and the highest net environmental benefits were obtained in TCC-scenario ii. The process contribution analysis found that thermal desorption process accounted for 80-95 % of impacts in almost all impact categories. Energy consumption contours and linear regression models were also developed to help drilling waste managers estimate the life cycle impacts of using hydropower-driven TCC to treat OBDCs with different water and oil contents.