Sustainability and waste management : a case study on an UK oil refinery during day-to-day and turnaround operations.

To achieve sustainability in the global economy requires all organisations to operate in ways which are equitable and socially acceptable, technological viable, economically affordable and with minimum impact to the environment. Worldwide, and in particular in the UK, the sustainability of the oil refining industry has come under increasing scrutiny in an environment with high energy demand and stringent regulations. The oil refining sector processes large amounts of raw materials and produces substantial quantities of waste which need to be treated, mostly at facilities away from the refinery site. Waste management represents a challenge to the industry not only because of the impacts to the environment but also due to high treatment costs. This thesis describes research carried out to investigate and address some of the problems related to sustainability, in particular the management of raw materials and waste, based on the Valero Refinery, Pembroke, Wales as a specific example. The starting point of this research was a review of general theory, legislation and practice for measuring, monitoring and managing raw materials consumption and waste production. This was followed by an analysis of specific waste management practices at the Valero Refinery which showed that individual process units can do much to improve their performance by increased monitoring and control. Following the identification, classification and quantification of refinery waste over 2007-2013, it was observed that although variable, the annual amount of total waste produced has shown an increasing trend from about 21 kt to 24 kt with a peak of 29 kt in 2011. Similarly, the total annual costs of waste treatment have increased from about £2.0 M to £5.0 M. From this trend it was identified that hazardous waste was the largest (about 75 % w/w) and costliest (about 70 % of total) waste to treat, composed mainly of fluoridic caustic (about 85 %) but with significant contributions from phenolic caustic and oily sludge. Finally, a novel application of material flow analysis (MFA) methodology was developed to detect points where value could be recovered and waste reduced during a refinery-wide turnaround for maintenance and project purposes. The MFA revealed that waste management practices, in particular collection, segregation and temporary storage of some wastes, can be improved to avoid environmental contamination, landfilling and transportation within and outside the Refinery boundaries. It also evidenced opportunities to investigate alternative treatment methods, especially for used catalysts