微量物质对乙烯装置的影响

Effect of Trace Contaminants on Ethylene Plant

微量物质可随裂解原料、稀释蒸汽和化学助剂进入乙烯装置,对裂解炉炉管造成损害、腐蚀管线与设备、使催化剂中毒,甚至影响下游聚烯烃装置的运行。乙烯装置中常见的微量物质主要有重金属、非金属及氧化物。硫会增加裂解产物中硫化氢的生成量,羰基硫可造成丙炔和丙二烯加氢催化剂活性下降,并污染丙烯产品;砷会腐蚀炉管并使加氢催化剂失活;钠会造成炉管腐蚀,加剧炉管内的结焦,还会促进CO和CO2的生成;汞能在低温设备中累积,侵蚀铝合金,造成设备故障,并降低催化剂的活性;CO2、甲基叔丁基醚、甲醇、氯化物及一些金属元素也会对乙烯装置产生不利影响。

Trace contaminants in feedstock, dilution steam and chemicals could enter ethylene plant and lead to damage to cracking furnace tubes, corrosions of pipe-line and equipments, catalyst poisoning, and disadvantageous effect on polyolefin plant. The common contaminants in ethylene plant are heavy metals, nonmetals and oxides. Sulfur would bring increase of hydrogen sulfide in cracked gas. Carbonyl sulfur would reduce activity of catalyst in hydrogenations of propyne and propadiene. Arsenic could erode the furnace tubes and cause deactivation of the hydrogenation catalyst. Sodium could cause corrosion of the furnace tube, aggravate coking within the tubes and generate CO and CO2. Mercury could accumulate in low temperature equipments, corrade aluminium alloy and reduce the catalyst activity. Carbon dioxide, methyl tert-butyl ether, methanol, chloride and some metal contaminants could also produce disadvantageous effect on ethylene plant.