Because Alchemy uses statics to keep track of its ram, etc, you sort of can't have more than one instance. The libraries would be sharing the same ram, which can cause problems.
However, you can dodge the issue by loading your alchemy libraries into separate Application Domains. I'm doing this in my project:
- Compile your libs as SWCs
- Extract the SWFs from inside the SWCs
- Embed the library SWFs in your application
- Use Loader.loadBytes to load your library into its own Application Domain
The other benefit of doing it this way is that if your alchemy lib crashes it won't affect any other alchemy libraries because they're using entirely separate ByteArrays for ram, etc.