SiO_2/S涂层和硫磷抑制剂的抑制结焦性能研究

RESEARCH ON THE COKING INHIBITION PERFORMANCE OF SiO_2/S COATING AND SULFUR/PHOSPHORUS CONTAINING COKING INHIBITOR

采用常压化学气相沉积法(APCVD)在退役25Cr35Ni乙烯裂解炉管内表面制备了SiO_2/S涂层,分别研究了表面涂层与裂解原料中添加结焦抑制剂的抗结焦性能;并对表面涂层与结焦抑制剂的联合结焦抑制性能进行研究。利用扫描电子显微镜(SEM)、能量色散谱仪(EDS)和Raman光谱对SiO_2/S涂层形貌、成分和结构进行分析,对焦层形貌进行表征。结果表明:SiO_2/S涂层粒子结合紧密,粒径为6～10μm,涂层厚度约为7μm;涂层由Si—O—Si三节环结构和非晶态的Si—O—S结构构成;炉管内表面经过涂层处理后,结焦抑制率为65.07%;裂解反应原料中加入结焦抑制剂的质量分数为200μg/g时,结焦抑制率为69.20%;表面涂层与结焦抑制剂联合使用时,结焦抑制剂最佳质量分数约为50μg/g,联合结焦抑制率为98.50%。

SiO2/S coating was prepared by atmospheric pressure chemical vapor deposition（APCVD） method on the inner surface of an off service 25Cr35Ni cracking tube in ethylene furnace. The anti-coking performance of the coating, adding sulfur/phosphorus containing coking inhibitor in feed and their combination was investigated respectively. The feature,chemical compositions and microstructure of the coating were characterized with scanning electron microscopy（SEM）, X-ray energy dispersion spectrometry （EDS）and Raman spectroscopy, so were the morphologies of coke deposits formed in various conditions. The results showed that the coating film was packed with 6--10 μm SiO2/S particles perfectly with a thickness of about 7 μm, and it was composed of three-member ring Si--O--Si structure and amorphous Si--O--S structure. The coking inhibition rates for coating and adding 200 μg/g coking inhibitor in feed were 65.07% and 69.20% ,respectively. However,for the combination of coating and coking inhibitor with an adding dosage of 50 μg/g,the rate of combined coking inhibition reached 98.5%.