Abstract: The deep-cut vacuum distillation can improve the light oil yield and reduce the secondary processing capacity of residual oil, which is an important development direction for refinery to improve product structure and economic benefits. According to the characteristics of two-stage vacuum distillation unit, the feasibility and effect of deep-cut by increasing the outlet temperature of vacuum heater were analyzed. Results showed that the peak heat flux exists in the middle and lower part of each tube of the furnace. The difference between the maximum and minimum oil film temperature on the fire side was about 20 ℃ and that on the back fire side was 6~8 ℃, due to the uneven heat flux. Based on the outlet temperature of the vacuum heater at 400 ℃, the total pulling out rate increased by 2.05 ,4.01 percentage points respectively when the temperature of the furnace outlet was increased to 410 ℃ and 420 ℃. According to the processing capacity of 8.0 MM TPY, the annual economic benefits can be increased by 6.56 million yuan and 12.83 million yuan respectively. Therefore, the economic benefits of the deep-cut vacuum distillation are very considerable.

Key words: two-stage, vacuum distillation unit, deep-cut vacuum, vacuum heater, coking

摘要： 减压深拔能提高轻油收率、减少渣油二次加工量,是炼油企业改善产品结构、提高经济效益的发展方向。针对双级减压蒸馏装置特点,分析了通过提高减压炉出口温度实施深拔的可行性和效果。结果表明,立管型减压炉每根炉管在炉膛中下部均存在热强度峰值,热强度不均导致向火面侧油膜温度最大与最小值相差 20 ℃左右,背火面差值为6~8 ℃。以减压炉出口温度400 ℃为基准,炉出口温度提高至410 ℃和420 ℃时,总拔出率分别增加 2.05, 4.01百分点,按8.0 Mt/a加工量,每年可增加经济效益分别为3 360万元和9 632万元,经济效益非常可观。

关键词: 双级, 减压蒸馏装置, 减压深拔, 减压炉, 结焦