15. Distillate and Residual Fuels

Question 1

■ Industrial and transport fuels in the middle and the bottom of the barrel?

Answer 1

■
▪ Kerosene
▪ Jet Fuel
▪ Heating Oil
▪ Diesel Fuels
▪ Residual Fuels

Question 2

■ Commercial Jet Fuel?

Answer 2

■
▪ Commercial jet fuels are hardly more than hydrotreated kerosene. But given the sensitive, 35,000-foot nature of the product use, the specifications
of the kerosene feed to the hydrotreater are considerably tighter.

▪ Jet A & Jet A-1 has a boiling spec of 205ºC to 300ºC. 205ºC 10 higer than initial boiling point.
▪ Freeze oint
▪ Smoke Point
▪ Aromatics Content (aromatics have a smaller hydrogen-to-carbon ratio than paraffins or naphtenes and are therefore more prone to incomplete combustion)
▪ Military jet fuel JP-5 and JP-8 has a lower 10% recovery point to allow more naphta cut.
– Reason for this is to expand the capacity of domestic refineries during emergencies.
– More countries moved from JP-5 to JP-8 as it has higher flash point spec., meaning it is safer to hande.

Question 3

■ Diesel
▪ Cetane Number?
▪ Blending Components?
▪ Quality?

Answer 3

■
▪ Outside the US automotive diesel fuel is known as gas oil. (the fuel has been boiled out of the crude and then condensed back to liquid).
▪ Blend of cetane (C16H34) and alpha-methylnaphtalene (C11H12).
▪ All the light gas oil components can be used for diesel blending, but as in gasoline some are better than others
– Paraffins have a higher cetane number (SRLGO)
– Aromatics have lower cetane number (CLGO)
▪ Numerous additives to improve performance:
– Organic nitrates for cetane improvement
– Pour point depressants
– Viscosity improvers
– Biocides to reduse slime
– Polymeric additives to reduce wax buildup for flow improvement
– Antioxidants to reduce varnish formation
– Copper deactivators
– Dispersants to reduce asphaltene deposition and fouling
– Antistatic additives to reduce explosions.