Two issues regarding the urea plant
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Accidents occur from time to time when inadequate flushing of urea emissions during shutdown prevents the machine from starting properly the next time. Personally, I think there are two reasons for this: 1. The operator is too busy during the parking process; they have to go to the 9th floor to start the discharge and flushing processes, and at the same time they need to operate the pumps on the first floor, close the shut-off valves, and flush the water pumps, etc. This approach makes it very tiring for the operators to climb up and down, and it reduces work efficiency, preventing timely rinsing. 2. Generally, it is required to flush the critical areas for 40 minutes; however, the operator has to stay on the 9th floor for those 40 minutes. It’s simply impossible to endure that time period. Climbing down and then back up again seems too exhausting, so they end the process hastily. In my opinion, solving this problem is not difficult: by replacing the shut-off valves at all flushing points with quick-shut off control valves and assigning the task of flushing and discharge to the central control system, operations can be carried out more promptly and efficiently. The rinsing is also more thorough. Please discuss possible solutions to this problem – whether the isolation valves at all flushing points should be replaced with rapidly acting isolation valves that are controlled centrally. What should be the reason? What are the reasons it shouldn’t be? Also, is the high-pressure flushing water pump a backup unit? Is it necessary to have a backup pump, and what are the reasons for that?
1. Management still needs to be strengthened; how can it be wrapped up hastily? 2. Is there no elevator? Do we have to climb up and down? 3. Is one person responsible for starting the pump and performing the flushing? Can’t we communicate via walkie-talkie? The actual issue raised by the original poster is a management problem.
1. Primarily, the workshop needs to strengthen its management, and employees should further enhance their sense of responsibility at work. 2. If controlled by a main control valve, check valves must be added at each flushing point. However, there are still issues with faulty check valves, causing the material to flow back and cause blockages.
Strengthening management is key. There is no need to have a backup pump for the high-pressure flushing water pump, as the pump operates stably and is rarely used.
Flush the 9th floor for 40 minutes. Flush HV202 and H203? These flushing operations shouldn’t be carried out for too long; otherwise, there might be excessive absorption, pushing the system into its explosion limit. Under normal circumstances, at least two people are required for flushing: one to perform the actual flushing, and the other to control the pump’s start/stop and monitor its operation. By observing changes in the pressure gauge of the flushing water on the first floor, it’s possible to determine whether water has entered the system. If all responsibilities are left to the main controller, a malfunction in the solenoid valve at the flushing point—such as internal leakage or blockage caused by crystallization—could prevent water from entering the system. Should the controller fail to detect this in time, serious consequences could ensue. During normal shutdowns, thorough planning is essential; there must be sufficient personnel with clearly defined roles, so that everything proceeds in an orderly manner. In cases of emergency shutdowns, different measures must be taken depending on the cause and the expected restart time, prioritizing actions based on urgency. Regular accident drills should be conducted to improve employees’ operational skills. Roles must be clearly assigned so that everyone knows what they’re supposed to do during emergencies; having multiple people performing the same task would result in a waste of manpower
Reply to 5# ythwangbo: I would like to ask how many people are needed to start up and shut down the main framework in your workshop?
Reply to 6# Zhang Xiaopeng: No specific figures have been recorded; for normal start-up and shutdown operations, there are teams composed of members drawn from various shifts, with around four or five people in such teams
Reply to 4# fjhuyuyang: Once in our workshop, there was a shutdown due to the inability to start the high-pressure flushing pump; we temporarily used an ammonium pump for flushing, but the condensate was not completely replaced, which resulted in extensive blockages in the flushing pipes. I would like to ask how you handle such situations when the flushing pump cannot be started during a shutdown
Reply to 7# ythwangbo: Thank you for your reply!
Reply to 8# Zhang Xiaopeng: It has never happened. As the saying goes, one should be prepared for potential dangers, so regular inspections are necessary.
Thanks for the great idea! But don’t you perform periodic tests on your high-pressure washing water pumps?