It can be done but will not be very rigid if the wall is 1.5mm. If you really meant ridged then that could be done and it would make it more rigid. Vertical ridges are no problem but horizontal ones might well create a problem with support. 8 inches might be slightly high for a lot of 200mm build height printers. An option would be to make 2 tubes that fit together.
To print it you will probably need to use a raft to avoid it detaching from the print bed.
If you put a PLA tube in boiling water for 10 secs then it can be shaped and should retain its strength after cooling.