焦化装置油气携带大量泡沫焦的原因分析和对策

Analysis of foam coke carry-over in delayed coking unit and countermeasures

延迟焦化装置的工艺特点决定了油气中会携带少量泡沫焦,但大量的泡沫焦携带往往造成装置被迫紧急停工。分析了大量泡沫焦携带的原因,主要是泡沫层前沿突破焦炭塔直筒段引起,而加热炉出口温度降低、反应压力降低、焦炭塔气速增加和消泡剂注入的突然中断都可能导致泡沫层厚度突然大幅增加,进而造成泡沫焦冲塔。为了避免冲塔,生产中应控制好焦炭塔料位、反应压力和反应温度等参数;在可能导致反应温度低的特殊工况下,控制好泡沫层厚度;改进分馏塔底的设计,让分馏塔底能容纳更多的泡沫焦。

In the delayed coking process, a small amount of foam coke carry-over in oil vapor is inevita- ble. Whereas, a large amount of foam carry-over will lead to emergency shutdown of the unit. The analysis shows that the large amount of foam carry over is mainly caused by the foam layer overflowing the coke drum straight section to the fractionators. The reduction of furnace outlet temperature, lowering of reaction pressure, the higher gas velocity in the coke drum and sudden interruption of defoaming agent injection will all lead to the sudden increase of foam layer thickness and coke drum flooding by foam. To avoid the tower flooding, the process parameters such as coke level, reaction pressure and reaction temperature, etc should be appropriately controlled. In addition, the thickness of foam layer should be properly controlled and the design of fractiona- tors bottom should be optimized so as to treat more foam coke at the bottom of fractionators.