Isolation valves for isolation of reboilers

Question

Isolation valves for isolation of reboilers

terrorist (Mechanical)

(OP)

1 Apr 21 13:57

Hello everyone,
We have one LPG column installed in our unit for recovering LPG from natural gas by thermoexpansion process. There are 3 more columns namely LEF, propane and naphtha. Recently we countered leakage from reboiler tube of one column. For attending the leak we required depressuisation of complete loop and column as there is no provision for isolation of reboiler. Hence for reducing the down time and flaring of huge amount of gas, we are planning to put isolation valves for isolating the reboilers.
I need your comments on this. Does any code prevent us from doing this or any other interlock we need to incorporate after this modification.

mk3223 (Mechanical) · Answer 1 · 2021-04-04 00:03:29

There is no restriction by Code for adding isolation valves in the process. But, you need to involve proper peoples to review the process changes, including Process & other Discipline Engineers, Ops and Maintenance, etc.
And, the new system may require to perform MOC and PHA to identify the potential hazard and provide the necessary safe guards for mitigation.

georgeverghese (Chemical) · Answer 2 · 2021-04-04 00:25:40

If you want to avoid installing relief valves specifically for this reboiler after putting in these isolation valves, then these valves will have to be locked open ( or car sealed open ). But to implement LO valves, there should be the appropriate strict operating safety culture in this plant ( which is subjected to Management Audit every year or so), otherwise LO valves cannot be used. Such valves should only be closed during maintenance (when required) and only with approved work permit. Plant Operations Management should also approve the use of LO valves for this application, not design team alone.

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Isolation valves for isolation of reboilers