Petroleum and refinery industries are facing many challenges like depleting resources, climate change and stringent environmental regulations. Efforts are being taken to increase economy, reduce energy consumption and emissions. Re-refining of oil has potential to increase the economy and reduce environmental footprints. Efficient use of energy with novel techniques for regeneration, co-generation and heat transfer enhancement can reduce the cost and pollution. Many processes in petroleum industries are hazardous, due to properties of the petroleum products and raw materials. This book provides an insight into research and studies on re-refining, enhanced oil recovery, energy efficient, environment friendly and safe practices.