Chrome tab - auto close

Team,

I have a 50 portal links and login credentials which has same portal design,
I need to open each portal and logged in and click download the reports it might take time from 2 mins to 30 mins the time might different from one portal to another ,

so i made a bot to open and click download the reports by adding tab , but i need to close the tab after downloading.

I was tried to create a loop to check each tab if download popup came made a simulate key strokes to close the current tab, however it went some time fails if portal is not loading or some issue ,

How to made the tab as auto close after downloading , and suggest me , if any alternatives to handle this