二氧化硅抗结焦涂层的制备及性能研究

Preparation and Performance of Silica Anti-Coking Coating

在裂解小试装置中,采用化学气相沉积法在裂解炉管的内壁沉积了二氧化硅抗结焦涂层,通过EDS和SEM等方法研究了二氧化硅涂层在裂解管内的分布规律,通过裂解结焦评价实验考察了二氧化硅涂层的抑制结焦性能。表征结果显示,在裂解炉管中间区域可以得到较好的二氧化硅涂层,但在裂解炉管的入口和出口处二氧化硅沉积较少,涂覆效果较差。实验结果表明,所制备的二氧化硅涂层在850℃的裂解温度下具有很好的抑制结焦效果,但经1 000℃蒸汽高温热冲击2 h后,抑制结焦效果急剧下降;所制备的二氧化硅涂层对裂解产物中乙烯、丙烯和丁二烯的收率影响不明显。

Silica anti-coking coating on the inner wall of cracking tube was prepared by chemical vapor deposition in a laboratory scale steam cracker for producing ethylene.The distribution of the silica coating along the tube was investigated by means of EDS and SEM.Its anti-coking performance was studied by cracking and coking experiment.Uniform silica coating was formed in the middle of the tube and uneven silica coating was got in the inlet and outlet of the tube.The coating showed high coking inhibition rate in the naphtha cracking at 850 ℃,but the coking inhibition rate sharply decreased after the silica coating was treated with steam at 1 000 ℃ for 2 h.In addition,the silica coating showed no obvious influence on the yields of ethylene,propylene and butadiene.