Fractional distillation

Preparation and Planning

This lesson contains diverse stimuli to aid students' appreciation of the physical attributes of various oil fractions, the relationship between burn-off temperature and properties of a fraction, and the commercial aspects of oil extraction. Students should be encouraged to consider the end-to-end journey of crude oil and to appreciate the critical role of fractional distillation in obtaining the highest possible value from each barrel.

All activities are paper-based though supported with numerous visual stimuli (slides and first hand accounts). Student debate should be encouraged and knowledge gained in this lesson will support numerous other curriculum areas touching on environmental issues and our responsibility to seek fuel alternatives.

About the MOD Topic

The supertanker, Torrey Canyon, hit rocks between Land's End and the Scilly Isles on 18th March 1967, threatening the West Country coastline and the French coast with over 100k tonnes of crude oil. Billed then as one of the UK's most serious environmental disasters, the Royal Navy (RN) and Royal Air Force (RAF) were called in to assist the coastguard and civilian clean-up efforts, plotting the direction of the oil and patrolling the coastline.

The RN Fleet Air Arm (FAA) and the RAF were called in 10 days after the Torrey Canyon went aground; by this point the ship had already been broken into two sections. Normal containment efforts were prohibited by severe weather conditions and so the Armed Forces were finally called in to bomb the tanker and burn off the tens of thousands of tonnes of oil which had already formed a slick 35 miles (56km) long and up to 20 miles (32km) wide around the area. As a last ditch measure, the RAF and the Royal Navy dropped 42,000lb (19,051kg) of bombs, 23,639 litres of petrol, 11 rockets and large quantities of napalm onto the ship. Flames could be seen for 100 miles (161km) and the smoke plum rose up to 30,000 feet.

Considerable lessons were learned from this spill, with the environmental disaster made far worse by the heavy use of detergent to disperse the slick. A report into the effect on the marine environment found that the detergent killed far more marine life than the oil.

Further Opportunities for Learning

Students propose possible solutions to minimise future pollution, including restrictions on shipping, clean fuels, co-ordinated clean-up efforts and voluntarily minimising consumption of oil derivatives.

Research other examples of MOD involvement in environmental damage limitation.

Students research alternative fuels and how they are obtained.

Students research other oil spill incidents e.g. Exxon Valdez, Piper Alpha, Napoli, compiling a picture of the relative impact of each and the clean-up exercises in each case.

Introduce the notion of carbon footprinting, inviting students to measure their own footprint and make recommendations for reducing this.

Student worksheet answers

Download the teachers notes PDF to access the answers for this lesson.