Circular Economy in the Oil and Gas Exploration and Production: Resource Recovery from Drill Cuttings and other Oily Wastes

Abstract

With an increasing awareness of minimising the environmental footprint combined with the inclusion of circularity in the oil and gas industry, stricter laws and therefore more rigorous treatment targets will have to be implemented in the waste/resource management. Increasingly complex solid and liquid waste streams result in the further need to implement safer, more advanced technologies. Emission levels, resource recovery, energy efficiency, worker safety, and input material flexibility will become key assessment factors. The vacuum thermal desorption process allows for the recovery of resources from different industrial hazardous wastes. At the core of the process is a specially designed vacuum evaporator chamber utilizing indirect heat and controlled vacuum to evaporate contaminants. With this process, resources can be recovered and solids/mineral fractions decontaminated therefore minimising the hazardous waste and bringing valuable resources back into the value chain. A wide range of input materials, independently from their consistency, can be treated using the same process, as a result of the batch-wise working principle of the vacuum evaporator. The process reduces air emissions derived from two sources. One originates from the thermal oil heating system (flue gas), the other from the vacuum desorption process (exhaust). For the latter, in an oily waste recycling facility that processes approximately 30,000 tonnes per year, <<100 m3/h are emitted, of which on average 96 % are nitrogen. Regarding resource recovery, typical output material parameters include clean solids with a TPH (up to C40) content < 0.5 %, oil in product quality with a recovery rate > 99.5 %, and clean water for moistening of the solids. Highest energy efficiency is achieved because the vacuum reduces the boiling point of the hydrocarbons by more than 100 °C. In addition, the recovered oil can be used as fuel to run the equipment. In conclusion, resources will be recovered and therefore hazardous waste reduced, emissions decreased and highest safety for workers observed. Aside from the above stated advantages of using indirectly heated thermal desorption, this process also offers the possibility to be operated using renewable energy. Therefore, guaranteeing zero emissions supporting the health & safety of our environment and its people.