What to do if the DCS loses power?
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As a catalytic cracking operator, we all know that our operations rely on observing the changes in DCS parameters in the operating room, but I often wonder, what should I do if the DCS loses power? Regarding this issue, I asked a lot of senior craftsmen around me, but they said that this kind of situation is very rare, and they have basically never encountered it. If this kind of situation really happens, they can also give some key points to deal with it, but I always feel that they are not complete and specific enough. There are so many things and equipment in the catalytic device, the system is quite complex, and we have so few personnel, so we must deal with it in priorities. Please discuss it with all friends of catalysis!
It's best to have a backup power source, just in case.
There is a standby power supply UPS behind the DCS.
1. Report to the squad leader after discovering DCS failure. 2. Operators at each position must immediately go to the scene for emergency treatment. 3. Contact the instrument and computer to resolve the DCS system failure. 3. Processing principles: 1. Put safety first and strictly prevent high pressure from changing into low pressure. 2. Keep the circulation of each road as much as possible to prepare for the resumption of production.
1) Notify the DCS class. And call up the screen through other device consoles. 2) The external operator should observe the primary meter on the spot, especially the feed amount, the liquid level pressure of the low-pressure parts of each high-pressure string, and the gas flow rate of the furnace. If there is no change, there is no need to adjust it to prevent fluctuations. 3) Use manually controlled parameters for key monitoring. 4) Change the parameters that need to be adjusted to secondary line control. 5) After recovery, adjust the operation records and process card indicators.
Are you talking about dcs black screen? If a single DCS loses power and the screen goes black, switch to another operating station and contact us for processing. If all operating stations have a black screen and do not recover within a short period of time, there is nothing to say. Just invest in self-protection and the device will stop working urgently.
How should the DCS communication interruption team handle DCS communication interruption? When data is lost due to DCS communication interruption, the monitor data is not displayed, and most instruments are still in the automatic state, but the signal cannot be output and the adjustment function is lost. When DCS communication is interrupted, the person on duty should immediately report to the factory coordination and workshop duty, and request an emergency shutdown at any time. At the same time, contact instrument processing and arrange personnel to monitor key parts of the site. 1. For fractional distillation, immediately check the pressure gauge on the top of the top reflux tank and keep in touch with the operation room through the intercom. If there is a slight change in pressure (20kp), report it to the squad leader immediately. 2. Immediately go to the on-site primary surface such as the regenerator differential pressure, and immediately use the intercom to contact the squad leader if there are any changes. 3. Remove the boiler from the steam drum to monitor the water level. If there is a change, manually adjust it on site to keep the water level within the normal range. If the self-protection is enabled and the water is full, it should be released urgently. 4. Go to the top of the boiler to monitor the water level, monitor the deaeration water level and observe the combustion situation of the furnace
If a single DCS is powered off or has a black screen, you can operate it on another machine. If the device encounters a power outage, the DCS will not lose power and can continue to work for about 4 hours.
I have only encountered this once. When I was driving and preparing to feed materials after shaking the bed, all DCS and controllers were powered off due to a short circuit while the instrument man was cleaning the ups. I had to do the following.: 1. Contact an electrician quickly to shut off the power to the entire device. 2. Treat it as an emergency. I drove the car after waiting. It's really luck, there is no feed, otherwise it would be very dangerous. Because all instrument controllers are powered off, the valves will be fully open or fully closed, which is completely uncontrollable. Since then, we have all developed * I'm used to seeing that the UPS power supply is abnormal. If there is just a power outage to the device, the DCS will not lose power because it is powered by UPS and can continue to work for 2-4 hours. The instrument display will be normal. If it's just a black screen (I've encountered this too), contact the instrument immediately for on-site monitoring, and it's usually fine.
Important systems are equipped with UPS, which can maintain the instrument valve control time for 20-30 minutes after a power outage. Make emergency plans and drills for power outages at ordinary times. After the DCS is completely powered off, it is necessary to check on site whether the instrument valves (air opening and air closing) are in safe positions.
DCS will not have a power outage because it is powered by UPS and can continue to work for 2-4 hours. The DCS operation station crashes and the on-site valve position will not be automatically adjusted. Just restart it. The DCS engineering station crashes, and the on-site valve position is the same as the wind stop action. When the DCS engineering station is restored, the control valve opening output may be 50%.
After the UPS loses power, will all valve position output signals change (fully open or fully closed)? Or is it fixed at the state before power failure? This post was last edited by mmhgb on 2009-3-2 20:15 ]
All DCS operations with a black screen rushed to the scene, cut the feed, closed each slide valve on site, operated the pneumatic machine and set off a torch to control the reaction pressure, the main fan controlled the regeneration pressure, the fractionation site changed to a three-way cycle, and the liquid level was controlled with reference to a primary meter or glass plate.
First, let’s talk about the DCS power outage. There is a power outage at the operating station and a power outage at the control station. After the DCS operating station loses power, the internal operator can neither see the screen nor adjust the operation, but the on-site control valve position will not change. The main processing steps are: 1. The outside operator goes to the site to confirm whether the main valve position is normal. 2. The operator can go to the DCS control station to make operational adjustments. 3. If production cannot be maintained, the DCS control station will be treated as an emergency shutdown due to power outage. Not only will the operation station be unable to control, but the on-site control valve will also be in the extreme position. Main processing steps: 1. Immediately go to the site to change the important control valve to the secondary line control 2. Go to the site to check the on-site instructions of important parameters and make corresponding adjustments 3. When the operation cannot be controlled, immediately stop the work urgently
Each device has a backup power supply, which is what we call a UPS. It automatically switches over when there is a power outage and can last for at least 30 minutes. In addition, the outside operator must have experience in emergency handling of the device so that it can deal with the UPS switching failure.
If all the DCS screens are black, immediately activate the feed self-protection, and the external operator will go to the site to check the self-protection and control valve operation. Because when effective monitoring cannot be carried out, various dangerous situations may occur, so we must prepare for the worst and not take chances.