SPListItemCollection Export To Excel timer job

I have a timer job that queries specific SPListItemCollection and transform it to DataTable.

I want to export this DataTable to an excel file that will be saved to a specific location (ftp)

how will I do the exporting to excel programmatically? can you share some code snippets that will work for this?

I have tried some codes but it asks me if I want to Save SaveAs or Cancel. What I want is it will immediately download this to a specific location (ftp)