The question is pretty broad. If you look at NFPA 30 it's not going to give you an answer because for operations, it requires that an analysis of the process be performed before the designer and AHJ decide the minimum requirements.
Questions I have are:
-- Batch or continious?
-- How is the ethanol produced?
-- What is the number and diameter of the storage tanks?
-- What is the standard for construction of the tanks?
-- Is the plant located in an area served by a Fire Department or is it in the boonies?
-- Does the plant have its own fire brigade and if so, what are their capabilities and limitations?
-- Do you have a water supply and what is its available fire flow?
Good luck.