Where are you getting mercaptan free butane?
Have you read of their removal?
Yes. You can use N2 to enable solvent injection.
Then you need to figure out how/when to vent it.
Lots of threads in the subject…
Search.
Read.
Ask clarifying questions before proceeding.
See also responses to: Will nitrogen compress butane gas into a liquid or just push liquid? - #209 by Obas2070