Radiation pump filter switching steps

I. Background Information 1. Unit where the accident occurred: Coking workshop 2. Time and location of the accident: January 30, 2013, at the bottom of the distillation tower 3. People involved in the accident: Coking Team XX 4. Casualties and economic losses: XXX, an operator from Team 3 responsible for distillation operations, suffered minor burns 5. Type of accident: Minor accident II. Course of the accident On January 29, 2013, it was detected that the pressure difference before and after the circulation extraction filter (south) at the bottom of the distillation tower was abnormally high. With the Spring Festival approaching, and in order to ensure safe production during this period, the workshop decided to clean this filter in advance. On that day, the night shift switched to the backup filter (North), while the other unit was prepared for shutdown, cooling down, and oil removal as well as coking removal. Around 5 o’clock after taking over the night shift on January 30, steam cleaning was started in order to transfer the oil stored in the filter to the sludge line. As a result, a fire accident occurred. Upon detecting the fire during shift, steam was immediately used to cover the area and fire extinguishers were employed to put out the fire. At the same time, the incident was reported to the workshop, the dispatch team, and the fire department. The workshop rushed to the scene right away to organize rescue and firefighting efforts, and also mobilized non-shift personnel living in the apartments to assist in handling the situation. With the cooperation of the department heads in the company and the fire brigade, the situation at the scene was quickly brought under control around 6 o’clock ； The disassembly, inspection, and cleaning of the filter were completed after draining all the remaining oil. At 2 p.m., the basic filter returned to normal operation. III. Cause Analysis: Direct cause: During the cleaning process, although low-pressure steam was continuously discharged to release water, it still contained water. Upon entering the filter, high-temperature residue experienced boiling, resulting in extremely high pressure that caused the high-temperature residue to leak from the flange cover and catch fire. Indirect cause: After removing the filter, it was found that the level of coke powder was almost at the same height as the inlet and outlet of the filter; there was a large amount of coke powder. The short section at the outlet of the filter’s oil drainage line was blocked by the coke powder, which prevented proper drainage of the residue oil – this was also an important factor. Management reasons: There is a lack of experience in the operation and management of heavy oil equipment, as well as inadequate consideration; no appropriate technical solutions and preventive measures were established in accordance with standards for operations related to switching heavy oil filters and other such equipment. Engineering reason: None. IV. Accident liability analysis: During this filter cleaning process, although it was anticipated in advance that steam containing water would cause problems, the workshop required that the steam be dehydrated before injection, and the opening degree of the steam injection valve was set to only 2 turns at the beginning. Nevertheless, even after dehydration, the low-pressure steam still contained a certain amount of saturated water, and there was a significant temperature difference with the contents inside the filter, which led to boiling ； The workshop bears primary managerial responsibility for this accident; the operational planning was inadequate and the plans were not detailed enough ； The operator on duty, while handling oil return, used steam for purging without first confirming whether the oil return line was unobstructed, which resulted in delayed pressure relief during boiling over; he is held partially responsible ； V. Lessons Learned from the Incident and Preventive Measures
Lessons learned from the incident: 1. This fire accident has made us acutely aware of the significant hazards posed by residue oil as such a type of **chemical. In future operations, it is necessary to proceed with caution, taking into account the characteristics of various hazardous **substances and corresponding preventive measures. Thorough risk analysis should be conducted, and work should be carried out in an organized and step-by-step manner in accordance with established plans. 2. Both workshops and teams should strengthen relevant training and learning. Emergency response plans should be revised and improved for various types of major hazard sources, especially those related to high-temperature residue oil, and corresponding drills should be organized to ensure that problems are identified and addressed promptly. Preventive measures: 1. Continue to intensify the identification of potential hazards, especially in areas where high-temperature heavy oil is used. Identify potential hazards, address them promptly, and maintain a record of such hazards. 2. To prevent similar situations from occurring again, the workshop has developed relevant technical measures and plans, as well as arranged learning and training ； 3. In response to this incident, specific treatment plans and emergency procedures have been developed for dealing with the situation after switching the hot oil pump, as well as after switching the high-temperature filter ； Special accident drills are organized to ensure that every employee is aware of the hazards associated with residue oil, thereby enhancing their safety awareness and firefighting skills, allowing them to make quick judgments and take decisive actions in the event of an accident. VI. Determination of responsibilities and handling: Through discussions in the workshop, the most direct cause of the leak and fire was identified, and the person responsible was given a warning ； Based on the summary, measures and plans were formulated to handle similar situations