Do you know why the tubes of a tubular furnace are coking

Tubular furnaces are mainly used in metallurgy, tubular furnace tube glass, heat treatment, lithium positive and negative electrode data, new energy, abrasives, and other professional measurement equipment under certain atmospheric conditions. Today, I would like to introduce the causes of furnace tube coking:
1. The quality of the material tar is unstable, prone to coking at high temperatures, or the tar has high water content, and the dehydration effect may be poor;
2. The feeding of the heating furnace fluctuates, causing the furnace outlet temperature to fluctuate from high to low;
3. Uneven heat distribution in the furnace causes overheating of the furnace tubes
4. If the feeding amount is too small or stopped, the tar flow rate in the furnace tube is too slow, and the heat transfer resistance of the oil layer increases, resulting in excessively high pipe wall temperature and formation of coking;
5. Incomplete cleaning of furnace tubes before commencement (referring to furnaces that have already burned coke), and the original coke in the furnace tubes has an induction effect. Why does coking promote the occurrence of new coke;
6. The flame burns the furnace tube, causing partial overheating and coking;
7. If the indicator of the thermometer fails to check, the furnace temperature increases, and no indicators are displayed, the oil in the tube will also be cracked and coking at high temperatures.
Have you understood the causes of coking in the tubes of the tubular furnace summarized above.