1-2hrs if you can speak English fluently.
If you need a translator that time could turn to 2-4hrs easily.
If you have a dependent add another 30 minutes.
basis step including
Oath, sign paper work
Review i589 personal information together
If you are not eligible for affirmative asylum your interview may be referred to immigration court. (For example someone apply asylum 1 year later of their last entry to the US)
If you are eligible game start
Interview about the prosecution
30-50questions
Ask legal required questions
15-20questions, say no to those questions
Case finished and Dismissal