A.0.65~0.75 B.0.55~0.65 C.0.85~0.95 D.1.05~1.15
A.<0.5% B.>2.0% C.=0.5-2.5% D.>2.5%
A.恩氏蒸餾 B.平衡蒸餾 C.閃蒸 D.精餾