MTO装置碱洗塔塔盘堵塞原因分析及应对措施

Analysis of Reasons for Tray Blockage in Alkali Washing Tower of MTO Device and Corresponding Measures

甲醇制烯烃(MTO)工艺是在催化剂作用下,通过连续流化床反应-再生形式,将甲醇转化生成乙烯、丙烯和其他副产品,同时产生少量甲酸、乙酸、二氧化碳、二甲醚、醛/酮类氧化物等副产物,其中酸性物质甲酸、乙酸、二氧化碳会造成设备和管道腐蚀,同时二氧化碳还会在分离系统的深冷部位降温后固化,影响分离系统运行。因此为了脱除工艺气中的酸性物质,在MTO装置烯烃分离单元设置碱洗塔,采用氢氧化钠碱洗的方法,但碱洗塔在运行中生成黄油,堵塞塔盘,影响装置运行负荷,针对黄油生成的原因进行分析,并提出了相应的解决措施,为碱洗塔的长周期运转提供理论保障。

The methanol to olefin(MTO)process is a continuous fluidized bed reaction regeneration process that converts methanol into ethylene,propylene,and other by-products under the action of a catalyst.At the same time,it produces small amounts of by-products such as formic acid,acetic acid,carbon dioxide,dimethyl ether,aldehyde/ketone oxides,etc.The acidic substances formic acid,acetic acid,and carbon dioxide can cause equipment and pipeline corrosion.At the same time,carbon dioxide will also solidify after cooling in the deep cold part of the separation system,affecting the operation of the separation system.Therefore,in order to remove acidic substances from the process gas,an alkali washing tower was installed in the olefin separation unit of the MTO unit,using sodium hydroxide alkali washing method.However,during operation,the alkali washing tower generates butter,blocks the tray,and affects the operating load of the unit.The reasons for butter generation were analyzed,and corresponding solutions were proposed to provide theoretical support for the long-term operation of the alkali washing tower.