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为抑制镍基不锈钢油道本身对吸热型碳氢燃料裂解的金属催化结焦积碳作用,采用化学气相沉积法在Ф3 mmφ0.5 mm,800 mm长的3128型不锈钢基体管道内表面分别沉积了TiN和Al2O3涂层,沉积温度分别为950和1050℃,沉积时间为3 h。通过SEM、EDS和XRD分析了涂层的形貌特征和组织结构。SEM结果表明,CVD法制备的TiN、Al2O3涂层结构均匀致密;EDS结果显示,实验制得的氮化钛涂层的组成为非化学计量比的TiN0.67,氧化铝涂层的Al和O原子比为1:3;XRD结果表明,实验所得到的TiN为立方晶相结构,Al2O3为惰性的α-Al2O3。以二甲苯为原料采用自制的超临界裂解装置对TiN、Al2O3涂层的钝化效果进行了评价。二甲苯超临界裂解实验结果表明,TiN涂层钝化效果不明显,而Al2O3涂层的钝化效果十分显著,达到2倍的钝化效果。
In order to restrain the metal-catalyzed coking coke deposition of the Ni-based stainless steel oil passage itself on the endothermic hydrocarbon fuel cracking, the inner surface of the 3128 type stainless steel substrate pipe with diameters of Ф3 mmφ0.5 mm and 800 mm was deposited by chemical vapor deposition TiN and Al2O3 coatings, the deposition temperature was 950 and 1050 ℃, the deposition time was 3 h. The morphology and microstructure of the coating were analyzed by SEM, EDS and XRD. The results of SEM showed that the TiN and Al2O3 coatings prepared by CVD were uniform and compact. The results of EDS showed that the composition of TiN coatings was non-stoichiometric TiN 0.67, Al and O Atomic ratio of 1: 3; XRD results show that the experimental results TiN cubic crystal structure, Al2O3 is inert α-Al2O3. The passivation effect of TiN and Al2O3 coating was evaluated using homemade supercritical cracker with xylene as raw material. Xylene supercritical pyrolysis experimental results show that TiN coating passivation effect is not obvious, while the passivation of Al2O3 coating effect is very significant, up to 2 times the passivation effect.