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In our refinery,straight run LPG is used as Automotive fuel LPG to meet the minimum MON spec of 88. Why is cracked LPG not used for Auto-LPG ? Will it not meet the MON spec ? What is the composition wise difference in Straight run and Auto LPG ?
 
Answers
06/06/2017 A: Sridhar Balakrishnan, Bharat Oman Refineries Limited , laksrid@yahoo.com
Any refinery straight run LPG generally will be used as Automotive fuel LPG , since it contains lot of branched paraffins , whose octane number is very high compared to normal paraffins and olefins. Cracked LPG cannot be used as fuel for Auto LPG since , dienes are generally present in cracked LPG particularly from FCC and Delayed Coker. In the hydrocarbon type composition of LPG olefins not favoured for automotive use , because it has very low octane number compared to its equivalent carbon number of paraffin component of the LPG . No major differences between Straight run and Auto LPG except for dienes content, motor octane number, all testing parameters are same for both LPG. Cracked LPG composition helps in meeting the octane (MON) of the fuel.
06/06/2017 A: Bruce Carr, Suncor Inc, matukaze1@hotmail.com
Cracked LPGs are mostly olefins. They are unstable and can combine with other olefins which would affect your MON.