退役炉管内表面二氧化硅涂层的制备及抗结焦性能研究

Preparation of SiO_2 coating for inner surface of cracking tube after service and its anti-coking properties

采用常压化学气相沉积法在退役Fe-Cr-Ni炉管内表面制备了SiO2涂层,对其抗结焦性能进行了研究。运用扫描电子显微镜和能量色散谱仪分析了原始退役炉管及SiO2涂层的表面形貌和组织结构;考察了在乙烯裂解的工艺条件下SiO2涂层的抗结焦能力,并对其抗热冲击性能进行了研究。结果表明,所制备的涂层表面完整、粒子结合致密,结焦试验2 h的结焦抑制率为70.6%;涂层可以经受7次900℃高温水冷热冲击试验。采用常压化学气相沉积法在炉管内表面制备SiO2涂层是行之有效的抑制结焦的方法。

SiO2 coating is prepared by atmospheric pressure chemical vapor deposition for the inner surface of Fe- Cr-Ni cracking tube after service, and its anti-coking performance is investigated. The morphologies of the inner surface and the distribution of elements composition along the cross section of the used cracking tube are inspected by means of scanning electron microscopy and energy dispersion spectrometry, so are the morphologies and elements composition of the SiO2 coating. The anti-coking performance of the prepared SiO2 coating is investigated under the conditions of naphtha steam cracking for producing ethylene, and its performance of thermal shock is also tested. The results show that the SiO2 coating is integral and compact. The coating reduces the coke deposition by 70.6% for 2 h＇ s coking experiments, and the thermal shock could stand 7 times in water quenching at 900℃. Preparation of SiO2 coating for the inner surface of cracking tube by atmospheric pressure chemical vapor deposition is an effective method for inhibiting coke deposition.