Effect of the preheating line in the catalytic nozzle
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What is the function of the pre-heating line? Everyone, please help look for it.
In the case of cut-off feeding, it prevents the raw material from condensing between the feed isolation valve and the nozzle line; it can also be referred to as an emergency return line
In the cutting mode, the isolation valve for the feed oil is closed; the isolation valve of the emergency return line is opened, allowing the feed oil to flow into the distillation tower. At the same time, the operator increases the amount of steam used for atomizing the fluid at the nozzle, closes the nozzle’s isolation valve, and opens the emergency return line at that location. The operator then opens the isolation valve for the feed oil entering the system
Here, we usually keep the valve open at a very low degree to prevent high pressure from building up in this area after it is shut off; if there is internal leakage in the valve, it can easily cause crude oil to enter the lift pipe. During startup, we adjust the pressure in the crude oil collection pipe to ensure the proper feeding pressure
Whether it is feeding or cutting, the purpose is to utilize the pre-heating line in a cyclic manner to ensure the proper operation of the pumps, similar to the function of a minimum flow line. Furthermore, when feeding material, the nozzle should be activated smoothly; as the flow rate through the nozzle increases, the flow rate of the preheating line should be gradually reduced, thereby ensuring stability in both flow rate and pressure.