Do you know why the tubes of tubular furnace coke?

The tubular furnace is mainly used for metallurgy, tubular furnace glass, heat treatment, lithium positive and negative electrode data, new energy, abrasive tools and other professional equipment under certain atmosphere. Today, I would like to introduce the causes of furnace tube coking:
1. The tar of the material is unstable, easy to coke under high temperature, or the tar has high water content, so the dehydration effect may be poor;
2. The feeding of the heating furnace shakes, causing the furnace outlet temperature to rise and fall;
3. Uneven heat distribution in the furnace makes the furnace tube overheat
4. 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, which makes the tube wall temperature too high and forms coking;
5. Before commencement, the coke cleaning operation of furnace tube is incomplete (referring to the furnace that has burnt coke), and the original coke in furnace tube has induced effect. Why will coke form to promote the occurrence of new coke;
6. The flame flapping furnace tube is partially overheated and coking occurs;
7. The indicator of the thermometer is out of order, and the furnace temperature increases. If there is no indicator, the oil in the tube will be cracked and coking under high temperature.
Do you understand the reasons for coking of tube furnace tubes summarized above.