How to deal with high residue value of paraffin oil
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Our company’s DN5000 coking fractionation tower has a residue feed temperature of 180°C to the fractionation tower. The temperature in the evaporation section is controlled at 365°C, the temperature of the wax oil collection tank is controlled at 360°C, and the temperature at the bottom of the distillation tower ranges from 315–325°C. The residue content in the wax oil is 0.5%. If the temperature of the wax oil collection tank is adjusted to 360–370°C, the processing capacity increases slightly, but the residue content in the wax oil rises to 3–4%. I’m not sure how to make adjustments to ensure that the product meets the required standards; I would appreciate some guidance from experts How much residual carbon does your company have?
We generally keep the residual carbon level below 0.5%, with typical analysis values ranging around 0.1-0.3. The reasons for excessive residual carbon are basically a low circulation ratio, high temperatures in the evaporation section, changes in the properties of the raw materials, and overloading. But it seems that the temperature in your evaporation section isn’t that high either, right? Is it operating under overload?
Reduce the top temperature of the coke tower, lower the gas velocity in the coke tower, decrease the temperature of the wax oil collection tank, and increase the flow rate of wax oil returning to the tower.
The design load is 100 t/h, while the operating load is 105 t/h – what could be the reason for the overload? The device has been in operation for a long time