Are there any design guidelines for the pneumatic purging of a diesel fuel line (1 1/2)from an undeground unloading station to an underground fuel bay? Would the air and diesel vapors create an explosive fuel gas mixture?
Purging of lines filled with hydrocarbons should always be done with an inert gas such as Nitrogen.
Portable bottles or quads can be arranged if its only an occasional requirement. Based on your line size you can get a lot done by this method.
Watch your pressure regulation, and have appropriate containment to avoid spills.
Rgds,
RKK