Abstract: In order to expand and renovate its 600 000 ton/year methanol distillation project,ENN Group Xinneng Energy Co.,Ltd.has replaced the existing fillers in the pressured tower by 69 layer valve trays.When the project starts up after renovation,some abnormal phenomena happens,including insufficient capacity,over-high tray pressure drop,high ethanol percentage in product,high liquid hold up on tray even flooding and so on,which all impact the operation.The reasons for these abnormal phenomena are analyzed,the further modifying ideas and the design philosophy of new tray are also put forward.Low back-mixing equal efficiency spray trays are used to replace 10 layers of valve trays in stripping section of the pressured tower.After the further modification,the capacity of the project reaches 760 000 ton/year and the product quality can meet China's superior grade GB standard requirement.Besides,the whole tower pressure drop reduces to 55 KPa from 100 KPa and the steam consumption decreases significantly.