Cr/W/稀土氧化物涂层的抑制结焦性能

急冷锅炉(TLE)是乙烯热裂解装置的重要设备,在运行中急冷锅炉炉管内壁会有结焦现象,降低急冷锅炉传热系数并增加炉管压力降,严重影响传热效果,需要进行周期性清焦.为了能够有效地抑制结焦,在炉管内壁表面上制备了一层Cr/W/稀土Re_xO_y惰性涂层,借助乙烯裂解结焦模拟装置、金相显微镜、扫描电子显微镜(SEM)和透射电镜(TEM)等设备从试样结焦表面形貌特征和结焦量等方面对所开发的涂层进行了抑焦性能研究.实验结果表明,无涂层试样表面存在催化焦和颗粒状焦,结焦严重;而涂层试样抑焦效果明显,表面不存在催化结焦,且焦层与涂层表面黏附性差结合较弱容易脱落,其结焦抑制率可达79.1%.

Anti-coking property of Cr/W/rare earth oxides coating for transfer line exchanger

Transfer line exchanger (TLE) is an important equipment for ethylene cracking unit. In actual operation, coke formation occurs on the inner surface of tubes in TLE. In effectively inhibit coking on the inner surface of tubes, inert coating of Cr/W/REO was applied on the surface of the tube metal. With aids of ethylene cracking simulator, metallurgic microscope, electronic scanning microscope (SEM), and transmission electron microscopy (TEM), coking inhibition performance of inert coating was studied, including the characteristics of coke surface and coking amounts of specimens. Serious coking occurred on the blank specimen surface with catalytic coke and granular coke, while the coated specimen showed great anti-coking effect without catalytic coke and the coke layer was easy to remove. Coking inhibition rate reached 79.1%.