Either you read a column or an entire range it is recommended to use Excel Application Scope.
Reading very large Excel files has a nice solution: do it in chunks of 10000 rows. Read A1:C10000
, then A10001:C:20000
and so on until you get less than 10.000 rows in the resulting datatable.
I don’t quite get what are you trying to do with the file. Is that a file on disk, an Excel file, some rows in Excel…