1 | Crack | The heat exchanger in the inlet pipeline of T-28 cracked | The heat exchanger E-17 inner leak | The feedstock will be blended with the production, the process must be shutdown | 5 | 3 | III | The operation procedure rules the production must be rechecked every 2h | |
1 | Pressure high | The pressure of T-28 is too high | The temperature of the cool water in the condenser on the T-28’s top is too high | The T-28 outlet gas'rsquo;s temperature is too high. The following condenser’s capability may be insufficient. The amount of the final production reduces up to 10% | 2 | 5 | III | | 3. The cooling public utilities should be expanded |
1 | Leakage | The reboiler E-15 leakage | The reboiler E-15 inner leaks | 1. The gas in T-28 leaks to the liquid. The production is lost partly 2. The heat will be wasted | 5 | 4 | IV | The operation procedure rules the production must be rechecked every 2h | |
1 | No flow | The reboiler E-15 flowrate is zero | 1. Power failure 2. The E-15’s feed pump P-25 is damaged | The reboiler E-15 is over heated, result in blockage or coking | 5 | 3 | III | | |
2 | Level low | T-32 aldehyde removing column | The T-32 outlet pump P-30s flow rate is too high due to its outlet control value widely opened on error or the public utility’s faults. The level of column T-32 is decreased down to zero. | The pump P-30 is empty, resulting in temperature raising. The potential fire and blasting hazard exists due to the high temperature | 5 | 3 | III | The pump has a output pressure indicator PT-17 | 2. Add an interlock: Stop the P-30A/B when the T-32’s level is too low |
3 | No flow | Heat exchanger E-06’s flow rate in tube pass (Dilute alcohol) | 1. The manual valve on T-03’s outlet pipe is closed by mistake. (In maintenance or startup/shutdown phase) 2. Feed-in pump P-30 failure 3. The manual valve on E-06’s outlet pipe is closed by mistake. (In maintenance or startup/shutdown phase) | 1. E-06 or its accessory flanges are damaged by over pressure. Ethanol leakage will result in fire or explosion hazards 2. Refer to the consequences of the T-03’s temp-high deviation | 5 | 4 | IV | | 4. Add an interlock system to shut pump P-30 down when its outlet pressure is too high 5. Confirm that the manual valves are timely opened in the maintenance, startup and shutdown operating procedures |
3 | No flow | Heat exchanger E-06’s flow rate in shell pass (Hot water) | 1. The control valve on water line malfunction 2. The level controller on V-01 malfunction | T-03’s temperature decreases rapidly, which will result in process shutdown | 4 | 3 | III | | 6. The V-01 has a twin backup vessel V-01B having its own level controller. The control strategy of the level controller on V-01 and V-01B should be changed to 2oo2 |
3 | Temperature low | T-03’s Temperature is too low | 1. Inlet flowrate is too high, refer to T-28’s deviation–flow high 2. The steam, feed into E-16, flowrate control valve PV-52 closed by fault 3. the steam pressure controller PT-52 closed by fault 4. The instrument-air failed | The steam feed into the T-03 through PV-52 is the main heat source of this process. Therefore, if the steam is failed, the whole process must be shutdown | 5 | 3 | III | | 16. Inquire the instruments department, apply an auto switch system on the instrument-air compressor 17. Enforce the maintenance on PV-52 and PT-52, which should be added in the operation procedure |
3 | Temperature high | T-03’s Temperature is too High | The steam, feed into E-02, pressure controller PT-52 opened by fault | The pressure of T-03 raised rapidly, the column may cracks | 5 | 2 | III | | 7. Add a control loop, control the inlet steam flowrate by T-03’s pressure or temperature 10. Add relief valve on T-03 |
3 | Temperature high | T-03’s Temperature is too High | The heat exchanger E-15/19’s efficiency decreased after long time working | T-03’s top reflux is insufficient, then T-03’s pressure increases, which make a positive feedback loop, resulting in the temperature and pressure increasing continuously | 2 | 5 | III | | 7. Add a control loop, control the inlet steam flowrate by T-03’s pressure or temperature |
3 | Level high | T-03’s bottom level | The T-03’s bottom level controller frozen in winter | The column T-03 is flooded | 2 | 5 | III | Insulating cover is applied | 8. Add some insulating measures against the frozen, such as heat tracing on the level control pipe lines 9. Add another different type instruments for generating level high alarm |
3 | Level low | The level on vessel V-08 is too low | The control valve on the P-31’s outlet is widely opened by fault | The pump P-31 is empty, resulting in temperature raising. The potential fire and blasting hazard exists due to the high temperature | 5 | 4 | IV | | 12. Add an interlock: Stop the P-31 when the V-08’s level is too low |
3 | Level low | The level on vessel V-08 is too low | The level controller on V-08 fault | No reflux to T-03, the temperature and pressure of T-03 increased (Refer to the T-03’s temperature high deviation) | 4 | 3 | III | | |
4 | Pressure high | T-11’s pressure is too high | The auxiliary steam valve is opened by operator’s mistake | Over-pressure results in the column leakage or pipeline leakages, may result in fire or blasting | 5 | 3 | III | | 14. Add a relief valve on the distillation column T-11 |
4 | Level low | T-11’s bottom level is too low | The level control valve is opened by fault, or by instrument-air failure | The heat exchanger E-09 is over heated, result in blockage or coking | 5 | 4 | IV | Level low alarm exists | 19. Add an interlock: Stop P-21 when the T-11 level is too low |
5 | Temperature low | T-21’s temperature is too low | The steam control valve is closed due to the steam feed in controller failure, or by instrument-air failure | Temperature decreased, much more ethanol is pumped out through the waste fluid pipeline. Ethanol lost | 5 | 3 | III | | 16. Inquire the instruments department, apply an auto switch system on the instrument-air compressor |
5 | Temperature high | T-21’s temperature is too high | The heat exchanger E-17’s efficiency decreased after long time working | No reflux to T-21, the temperature and pressure of T-21 increased | 2 | 5 | III | | |
5 | Level high | T-21’s bottom level is too high | The T-03’s bottom level controller frozen in winter | The column T-21 is flooded, the process must be shutdown | 2 | 5 | III | | 8. Add some insulating measures against the frozen, such as heat tracing on the level control pipe lines 9. Add another different type instruments for generating level high alarm |
5 | Level high | T-21’s bottom level is too high | Pump P-19 failed | T-21 will serious flood. Furthermore the T-21 may be damaged due to the liquid weight | 5 | 2 | III | | 29. Enforce the maintenance and routing inspection on P-19 |
5 | Leakage | E-17 inner leakage | E-17 inner leakage | Feedstock blends with the production gas, result in the increase of COD. The cost of waste water treatment will increase | 5 | 4 | IV | The operation procedure rules the production must be rechecked every 2 h | |
5 | Level low | V-24’s Level is too low | The control valve on the P-20s outlet is widely opened by failure | The pump P-20 is empty, resulting in temperature raising. The potential fire and blasting hazard exists due to the high temperature | 5 | 4 | IV | | 25. Add an interlock: Stop P-20 when the V-24 level is too low |
5 | Level low | V-24’s Level is too low | The level controller on V-24 failed | No reflux to T-21, the temperature and pressure of T-21 increased(Refer to the T-21’s temperature high deviation) | 4 | 3 | III | | |