Repeat Rupture Discs (RD) bursts shut down a Urea Plant each time.
Article Type: | Root Cause Analysis (RCA) |
Category: | Mechanical |
Equipment Type: | Pipelines and Miscellaneous Problems |
Author: | S. Raghava Chari |
Note: This root cause analysis (RCA) is from real-time scenarios that happened in industries during the tenure of two or three decades ago. These articles will help you to improve your troubleshooting skills and knowledge.
Urea Plant’s first Flash Separator (FFS) Rupture Discs Burst repeatedly a few years after commissioning.
Since the rupture disc (RDs) functioned well during the last 5-years fit-up problems are unlikely.
Perhaps, de-bottleneck steps achieved higher than rated capacities streams’ throughputs have increased first flash separator pressure higher than before.
Verifying was not easy because of the older generation pneumatic instrumentation and not saved charts.
The author found from the Process Licensor data sheet that RDs are of
1) Burst Pressure (BP) 21 bars and
2) 30% margin between burst and operation pressures and 5%burst pressure tolerance.
That means the RD could burst at 0.95*21 = 19.95 bars. In addition, the operation pressure shall be < 70% burst pressure i.e. <19.95*0.7=13.965 bars is necessary for reasonable RD lives!
The old batch RDs lasted perhaps because of +ve tolerance and lower vessel pressures at the former lower production rates.
Since the operation pressure now is 19.95 bars and temperature 165oC, the author insisted on getting 5% tolerance RDs of stamped BP = 19.65 / (0.9*0.95) =21.05 bars at 165o C. and holders to suit the Indian Co the present RDs supplier.
This meets the code requirements as vessel design pressure is 21.5 bars and thickness 16 mm against the calculated 11 mm +3 mm corrosion allowance.
The new RDs eliminated nuisance RD bursts, associated plant shutdowns, and lost production.
Author: S. Raghava Chari
Do you face any similar issues? Share with us through the below comments section.
If you liked this article, then please subscribe to our YouTube Channel for Instrumentation, Electrical, PLC, and SCADA video tutorials.
You can also follow us on Facebook and Twitter to receive daily updates.
Read Next:
Lube oil consoles of rotary equipment packages in industrial process plants are usually equipped with…
Rotating equipment packages such as pumps, compressors, turbines need the lube oil consoles for their…
This article explains how to blink lights in ladder logic with a detailed explanation video…
In this article, a simple example will teach you the conversion from Boolean algebra to…
In this article, you will learn the PLC cooking timer example for kitchen automation using…
Learn an example PLC program to control a pump based on level sensors using ladder…