Consultation and review of heat transfer oil process flow diagram

Could you provide the relevant flowcharts and existing measures?

Use a liquid seal or nitrogen seal to isolate air: to prevent the high-temperature heat transfer oil from coming into contact with air and oxidizing or deteriorating. Nitrogen sealing: Low-pressure nitrogen is introduced into the high-level expansion tank for sealing, while a breather valve is installed in the oil storage tank to maintain pressure balance. This is a more thorough and effective sealing method. The overflow can go to the low-level tank

The volume of the oil storage tank must be sufficient to hold all the heat transfer oil in the system after shutdown (the tank is not equipped with pipes to allow oil to flow outside the system). The overflow from the elevated tank flows into the oil storage tank.

Solution for the rear end of the overflow pipe: 1. Gravity-driven flow of the overflow pipe → sealed receiving tank at a lower level (oil storage tank/overflow collection tank). The pipeline should have a slope of ≥3‰, with the pipeline running in a downward direction throughout, to prevent any accumulation of liquid in pockets； The outlet of the overflow pipe is inserted below the liquid level in the low-level collection tank, with a liquid seal in place ； ① All oil spills are contained and recovered completely, with no leakage ； ② The liquid seal isolates the gas phase, preventing air in the collection tank from flowing back into the secondary expansion tank and ensuring that the nitrogen seal remains sealed and effective. The top of the low-level collection tank is equipped with a vent pipe (flame arrester + breather valve), a level gauge, and an overlevel alarm ； Install a pumping unit to regularly return the collected heat transfer oil to the secondary system or the waste oil tank. In Option 2, a U-shaped liquid seal section is added to the overflow pipe before it is connected to the low-level sealed collection tank; the height of the U-shaped liquid seal is greater than the maximum set pressure of the nitrogen seal ； Even if there are fluctuations in the nitrogen pressure in the expansion tank, the nitrogen will not escape through the overflow line, thereby maintaining a slight positive pressure inside the tank. Operating principle: Primary-side heating. The thermal oil furnace heats the primary thermal oil to a high temperature; the primary circulation pump then drives the hot oil into the tube side/shell side of the heat exchanger, transferring heat to the secondary-side thermal oil ； After cooling, the heat transfer oil is returned to the heat transfer oil furnace for reheating, thereby providing a steady heat source. Closed secondary circulation: The secondary circulation pump drives the secondary heat transfer oil to flow through the heat exchanger to absorb heat, which is then delivered to the process equipment in Class A workshops (such as reactor jackets), where it releases its heat to the process materials ； The cooled heat transfer oil returns to the heat exchanger to absorb heat again, forming an independent closed loop. Secondary expansion tank + nitrogen seal: A high-position sealed expansion tank is installed in the secondary system, along with a self-acting nitrogen seal device (nitrogen supply valve + nitrogen release valve) to compensate for the volume changes caused by the thermal expansion and contraction of the heat transfer oil; when the temperature rises, the volume expands, and the excess heat transfer oil flows into the expansion tank ； Cooling contraction → The expansion tank replenishes oil to the system, keeping it filled with liquid and preventing cavitation in the circulation pump ； Hermetic protection with a slight positive nitrogen pressure: The gas phase inside the tank is maintained at a slight positive pressure of nitrogen, thereby isolating it from air.

Since it is a Class A workshop, the requirements of the factory construction fire protection regulations as well as the \"Petrochemical Design Code\" should be followed. In the case of consulting and reviewing process flow diagrams, it is necessary to first check whether they meet the specifications regarding hot oil

The overflow port returns to the heat transfer oil receiving tank.