Emergency response plan for leaks and fires in the high-pressure system of hydrocracking

Pressure relief, emergency shutdown； It should not be extinguished lightly; fire-fighting water should be used to protect the equipment surrounding the area where the fire is occurring ； Release completely, replace with nitrogen, extinguish the fire ； During the pressure relief process, attention must be paid to controlling the liquid level, regulating the fire in the heating furnace, and preventing secondary issues such as human poisoning and explosions.

Be careful: never use cold water in areas where high temperatures are present, as uneven heating can cause the pipes to leak more severely. You can refer to post zgd1237 on \"What to pay attention to in case of leaks in areas with high hydrogen concentrations\": http://bbs.hcbbs.com/viewthread.php?tid=397908&highlight=%B8%BB%BA%AC%C7%E2%C6%F8

1. Turn on the fire suppression steam curtain； 2. Emergency pressure relief, shutdown of the unit 3. Discharge of oil from the rear section

The most important thing is to relieve the pressure as soon as possible; relieve the pressure at both 0.7 Mpa and 2.1 Mpa, and then replace it with nitrogen. Fire steam and fire foam can be used.

Thank you for your advice, everyone. I want something like an operation card; if anyone has one, please share it with me. Thank you!

Fire caused by a leak in a high-pressure system (1) Accident symptoms 1) When the leak is significant, a noticeable leaking sound can be heard. 2) If it is in a high-temperature area, it may catch fire. (2) Cause of the accident: A leak occurred in the high-voltage system, which is highly dangerous. (3) Accident confirmation 1) When the leakage is severe, the sound of the leakage can be heard clearly. 2) If it is in a high-temperature area, it may catch fire. (4) Accident handling – Immediate steam shielding is required; for leak points that can be shut off, do so immediately before proceeding with further actions, being careful to prevent hydrogen sulfide poisoning. If the leak site cannot be shut off, or if shutting it off is extremely difficult and may pose a risk to the operator’s safety, operations should be halted for handling. – If the leak is near a heat source or upwind of the furnace, pressure must be relieved at a rate of 2.1 MPa/min immediately to shut down the system urgently. (5) In a defensive mode, any leak that can be sealed off should be done so right away, followed by further handling. If the leak site cannot be shut off, or if shutting it off is extremely difficult and may pose a risk to the operator’s safety, operations should be halted for handling.

Accident symptoms: Abnormal noises were heard inside the unit; system pressure dropped rapidly; the combustible gas alarm in the unit went off.
Cause of the accident: Aging of high-pressure equipment led to leaks.
Confirmation of the accident: On-site inspection confirmed a large-scale leak in the high-pressure system.
Response measures:
1. Activate the emergency pressure relief button at a rate of 0.7 MPa/min.
2. Trigger the gas alarm; if a fire occurs, trigger the fire alarm as well.
1. Carry out emergency pressure relief to prevent further escalation of the situation.
2. Ensure the safety of personnel and equipment during the response process.
1. In cases of large-scale leaks, fires, explosions, and poisoning can occur; appropriate preventive measures must be taken.
2. Emergency pressure relief may cause leaks in other equipment; caution is required.

Level A procedures:
– The person who discovers the accident should immediately report to the shift supervisor.
– Contact the control room and the workshop to inform them of the situation.
– Contact the flare station to prepare for pressure relief.
– Contact the tank farm to stop feeding raw materials.
– Inform the tank farm to switch to an alternative pipeline.
– Trigger the gas alarm; if a fire occurs, trigger the fire alarm as well.
– Activate the emergency pressure relief button at a rate of 0.7 MPa/min.
– Switch the ESD display to the “Interlock Logic Diagram (Unit)” mode.
– Confirm that the emergency pressure relief valve is in the open position on the ESD display.
– Verify on-site that the emergency pressure relief valve is indeed open.
– Confirm that system pressure has dropped significantly.
– Ensure that the operating raw material pump has stopped.
– Close the electric valve at the outlet of the raw material pump.
– Close the flow control valve at the outlet of the raw material pump.
– Confirm that the operating hydrogen pump has stopped.
– When the exit temperature of the reaction effluent/raw material oil heat exchanger tubes is below 180°C, shut down the feed water pump according to the relevant procedures.
– Close the inlet and outlet valves of the feed water pump.
– Close the valves at both ends of the feed water injection points in the reaction effluent/light fraction oil heat exchanger.
– During pressure reduction, control the raw material oil buffer tank, high-pressure separator, and low-pressure separator.
– When system pressure drops to 2.0 MPa, shut down the cycle hydrogen compressor according to the shutdown procedures.
– Confirm that system pressure has dropped to a slight positive level.
– Close the emergency pressure relief valve.
– Use hydrogen-rich light fraction gas to control the pressure in C1106 and direct it to the low-pressure separator.
– Confirm that the reaction system has been relieved of pressure.
– Shut down the heating furnaces in the distillation system immediately.
– Drain all oil from the containers in the distillation system.
– Stop all operating pumps in the distillation system.

Standby state:
• System pressure is at a slight positive level.
• The distillation system is in a state where oil is stored.
In this state, if the leak is repaired, the unit can resume operations according to the normal startup procedures. If the leak cannot be repaired, the unit will remain in standby mode

Fire incidents near high-voltage equipment: Immediately assess the extent of the fire and its location. If the fire is small, use steam from fire extinguishing systems to cover the area and carry out firefighting efforts. If the fire is severe and poses a threat to the safety of the equipment or installations, immediately report the fire as required, notify the fire department and the production control center, and take the following actions: 1) Immediately shut down reactor heater F101 (including the permanent lights). 2) Stop the air preheating system and open the flue dampers. 3) Quickly open the pressure relief valves at 0.7 MPa/min and 1.4 MPa/min to relieve pressure, reducing the pressure in the reaction system to a slight positive pressure. 4) Confirm that the make-up hydrogen compressor K101, the circulator K102, and P102, P103 shut down due to interlock. 5) Stop P10l, cease feeding to the reactor, and redirect the diesel product to a short-cycle in the distillation system. 6) When the pressure drops below 0.7 MPa, add an adequate amount of nitrogen to the system if necessary, and use nitrogen to continue cooling. Note: When the temperature of either surface of the reactor is below 93°C, the inlet pressure of reactor R101 should be less than 3.0 MPa. 7) Closely monitor all high-level liquid levels to prevent them from becoming too high. 8) Close all valves in the boundary area, especially those on the fuel gas and fresh hydrogen lines. 9) The distillation system shall be maintained in circulation or handled according to normal shutdown procedures.