A.爐管過(guò)長(zhǎng) B.開(kāi)停車次數(shù)多 C.管壁厚 D.催化劑裝填過(guò)量
A.800~1000 B.1200~1300 C.1000~1200 D.1100~1300
A.2 B.10 C.1 D.5