How to deal with power outage accidents in diesel hydrogenation units
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2007.6.20.15: 05 The internal operation found that there was a power failure in the operation room. At the same time, the compressor DCS and ESD alarmed at the same time and displayed K-101.K-102.P-102.P-103 to stop. After on-site confirmation and consultation with dispatch, it was a power outage accident and all machines and pumps were out of service. After 10 seconds, the operating room light went out again. Ask the dispatcher to confirm that it was a power plant failure that caused the entire plant to shut down the high and low voltage power supply (the operating room was shut down for 25 minutes from 15: 04-15: 29, on-site parking for 40 minutes from 15: 04-15: 44). Immediately assign two outside operators to the Gaofen site to close the Gaofen liquid level regulating valve, auxiliary line valve and front and rear hand valves, and check the actual liquid level of the Gaofen glass plate. It only took 8 minutes for the high-grade liquid level to drop from 39.62% to 4.47%, which is 15: 05-15: 13. At this time, the system pressure dropped from 7.86MPa to 6.86MPa. It only took 15 hours for the system pressure to drop from 7.86MPa to 3.35MPa.: 05-16: 05, the high-point liquid level is re-established to 44%, and its regulating valve is put into use and the oil is intermittently reduced to the low-point liquid level. D-105.D-104 pressure control is changed to remove the torch and close the dry gas desulfurization valve. At the same time, the internal operation controls the pressure relief speed based on the no temperature rise of the R-101 bed, and the maximum temperature of the R-101 bed reaches 330.63°C (TI-3127B). Close the front and rear hand valves of the low dividing position regulating valve, and the reaction is interrupted to reduce oil by fractionation. In addition, assign 2 people to close the outlet valves of each pump and press the pump stop button, in order:: P-103.P-102.P-101.P-201.P-202.P-203.P-204. Each air-cooled motor and each auxiliary oil pump. Strengthen the turning of each pump after stopping to prevent shaft locking. After the other two people went to extinguish furnace F-101, they opened the front and rear hand valves of PIC-3119/B, and the internal control controlled the pressure of D-106 at 1.12MPa (because the supply of oil, gas and hydrogen was normal). After stopping the pump, the two people go to stop C-201 and C-202 stripping steam, that is, close the hand valve of the stripping steam regulating valve. Then close the hand valve in front of the D-201.D-202 interface regulating valve, and slightly open the C-201.C-202 stripping steam terminal until the condensation is visible. Change the pressure control of D-201 to the torch and close the valve to C-203, close the valve of the rich and poor liquid inlet and outlet device of C-203, and close the valve of C-203 to D-203. When the pressure of D-104.D-201 cannot be maintained, open the D-104.D-201 step nitrogen valve to maintain its pressure. 15: Within 30 days, the operation found that the regulating valve on the DCS failed and the purification air pressure was low and an alarm was issued. At this time, the purification air pressure was only 0.29 MPa, and the flow into the device was zero (the purification air pressure reached 0.01 MPa when it was the lowest). Immediately notify the external operator to change PIC-3119/B.LIC-3109 to the on-site auxiliary line to control D-106 pressure and D-103 liquid level, and close the front and rear hand valves of the regulating valve. Purifying wind until 16: 40 is restored. At this time, the internal operation notifies the external operation to put the PIC-3119/B.LIC-3109 regulating valve into use and close the auxiliary line valve. Two of them strengthened the maintenance of the compressor after shutdown, strengthened the inspection of the device after emergency shutdown, and promptly dealt with leaks, leaks, and leaks to avoid further expansion of the accident. Production will resume after high and low voltage power is restored. Things to note: The following matters should be paid attention to when a high-voltage and low-voltage power outage accident occurs based on the current situation of diesel-electric conversion equipment. 1. Immediately after the accident, send 2 people to the auxiliary line valve of the Gaofen hydraulic control valve to close the auxiliary line valve. And leave someone to confirm the actual liquid level of the high-resolution glass plate to prevent oil leakage and cross-pressure accidents. 2. Immediately after the accident, send someone to close the P-103 and P-102 outlet valves at the same time to prevent cross-pressure. 3. People must be put first when handling accidents to ensure personal safety. 4. In the process of handling accidents, unified command and standardized operations must be achieved. 5. Strengthen the turning work after the large unit and hot oil pump are stopped. 6. Contact internal and external staff in a timely manner to confirm every step and respond to everything. 7. When the temperature at any point of the catalyst bed in the reactor exceeds 420°C or the temperature at each point of the entire bed is ≥ 15°C, start the emergency venting system. 8. During the process of cooling and reducing pressure, it must be observed that when the temperature at any point in the reactor catalyst bed is lower than 93°C, the system pressure cannot be greater than 2.375MPa. 9. Pay attention to each static sealing point.
What the poster mentioned is instantaneous low voltage. Many variable frequency motors will be affected. The probability of tripping is more than 90% (I have counted). Non-variable frequency motors generally do not trip. It is usually caused by fluctuations in the superior power grid or fluctuations in the high-voltage section. Regarding the instantaneous low voltage, a plan must be made according to the conditions of the motors in each process.
Our company also often encounters this problem of power failure. Generally, it occurs more often during lightning. But here, the power grid is cut off and restored within a very short period of time (perhaps only 1 to 2 seconds). There is no pattern in the motor that stops after each power failure. It is also difficult for operating employees to find problems, which poses a huge safety hazard. Contact the power supply department and the answer is that there is no solution. Dear brothers, how do you usually deal with such problems?
I am deeply touched by what the poster mentioned about the electric shock. I have personally experienced it no less than 20 times, basically two or three times a year. The accidents I dealt with during the electric shock are really scary now when I think about it. However, I feel that accidents can be minimized as long as the power is shaken by mastering a few points. 1. Prevent high pressure from flowing into low pressure, mainly feeding materials to the high-pressure separator and high-pressure system, and closing all valves between the systems when power is shaken. 2. On the premise of ensuring personal safety, mainly protect the catalyst and equipment. This mainly involves appropriate temperature and pressure reduction, nitrogen replenishment into the circulation system, and appropriate emissions. 3. Let the circulation compressor start as quickly as possible. Stop the new hydrogen machine, 4. Close the boundary valve that may cause danger, 5. Let the distillation system circulate on its own under the premise of stability. Of course, what I said may be very general, and the specific operation may need to be experienced first-hand to be clear. However, I feel that as an operator, whether it is internal or external operation, the first thing is to stay calm and composed, not to panic, and usually to improve the basic skills. For example, when production is stable, Duoduodu * The emergency shutdown method includes not only power failure, but also what to do when the circulating water stops, what to do when the fuel gas stops, what to do when the steam or hydrogen stops, etc. You can also classify the operating points into cards and put them in a fixed location so that they can be easily accessed when needed to guide the operation. The above is my personal experience, I hope friends can correct me.
After a power outage, once the compressor stops operating, the UPS battery can usually power the DCS for 30 minutes. The device needs to shut down in an emergency, turn off the furnace, and relieve pressure. Pay attention to monitoring the bed temperature (when a certain point reaches 420 degrees Celsius or a certain point exceeds the normal temperature of 30 degrees Celsius, the pressure will be released urgently), cut off raw materials, retreat to a safe state, and resume operations after inquiring about dispatch and ensuring that the power is sustainable.