It is, however, possible to convert a 3DS ROM into a Citra (Citra being the code name for the 3DS) Installable Archive, which will play off your SD Card once installed, provided you patch out the signature checks with CFW, install a legit CIA dumped from a system with a pack-in game - which your converted ROMdump will not be - or somehow miraculously figure out how to properly sign your CIA with Nintendo's private signatures. Which you won't do, unless your name is Merasmus or something.
So, either fork out money for a Sky3DS and make sure not to get banned from online play for not having a unique private header, or get a hardmod, install a9lh, and enjoy homebrew and warez.