一趟 vs 一次、is there any difference?
My English is not good. This answer translated by Google Translate.

Nowadays these two words are mixed and there is no serious mistake. But here are some explanations.

趟

趟 is generally used for round trips in a specified time. Example:


  我今天去了兩趟超市。
  
  I went to the supermarket twice today


I went and came back twice. Now I'm home.

次

次 emphasizes number of travels and your experience from the trip. Example:


  我去過两次北京。
  
  I went to Beijing twice.


I just want to tell you that I have that trip.