Form 8582 vs Form 8990 in regard to Schedule K-1 for a Publicly Traded Partnership

I have a Publicly Traded Partnership , Energy Transfer LP, with a K-1.

What is the difference Between Form 8582 and Form 8990?

Why would an accountant use Form 8582  instead of Form 8990?

Why would an accountant also use Schedule E?

My K-1 Box 13 K, Excess Interest Business Expense, is $2.

 

Thank you.