自由基引发剂对重油加氢裂化的影响研究

在高压釜式反应器中考察了添加过氧化特二丁基(DTBP)、偶氮二异丁腈(AIBN)和单质碘(I2)三种自由基引发剂对克拉玛依蜡油、孤岛减压渣油加氢裂化反应的影响。在氢气初始压力7.0 MPa,反应1 h的条件下,对引发剂用量、催化剂用量、反应温度等影响因素进行了考察。结果表明,添加自由基引发剂后,重油的加氢裂化转化率,轻质油收率以及HDS、HDN都明显增加。添加质量分数5 000×10-6或10 000×10-6引发剂后,蜡油和减压渣油加氢裂化的轻质油收率最大可增加10%、13%,HDS和HDN最大可增加11%和7%左右。采用较少的催化剂用量或较低的反应温度即可以实现较高的重油转化率和轻质油收率。相对而言,DTBP和I2的促进作用优于AIBN。添加引发剂前后的加氢裂化的产物分布对比说明,引发剂的加入有利于蜡油或渣油原料一次裂化产物的生成。

Effect of free radical initiators on the hydrocracking of heavy oils

The effects of three free radical initiators including azodiisobutyronitrile (AIBN), Di-tert-butyl peroxide (DTBP) and iodine (I₂) on the hydrocracking of Kelamayi vacuum gas oil (KVGO) and Gudao vacuum residue (GDVR) were investigated in an autoclave-style reactor. The effects of the amounts of initiator and catalyst added and the reaction temperature on the hydrocracking were examined under an initial H₂ pressure of 7.0MPa (reaction time, 1h). The results indicated that the conversion of heavy oil, the yield of light distillates, and the extent of hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) are improved largely by the addition of the initiators for hydrocracking. By adding 5000×10^-6 or 10000×10^-6 initiator in the feed, the yield of light distillates can be increased by 10% or 13% and the extent of HDS and HDN is increased by about 11% or 7%, respectively. DTBP and I₂ are better initiators in the hydrocracking than AIBN. An analysis of the cracking-products reveals that the addition of initiators is favorable for the formation of the primary cracking products with VGO or vacuum residues as the hydrocracking feed.