Chlorine safety valve issues
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Dear sea friends: Regarding the existing liquid chlorine storage tanks, some information found on them is as follows: The safety valve was previously configured as a burst disc in combination with a safety valve, and the safety valve did not have a bypass line. Regarding pressure storage tanks, clause 6.4.2(d) of SH/T3007-2014 states that the safety valves for such tanks should be equipped with an online standby safety valve as well as a backup line for the safety valves. The current storage tank does not have any extra pipe connections; here are a few ideas for now: no online backup. The rupture disc + safety valve setup is being used; a secondary line is wanted, but considering corrosion issues, is it really necessary to add one?
The safety valve was previously configured as a rupture disc + safety valve; the safety valve does not have a bypass line
It’s some reference drawings that were found, along with information about the conditions at the old factories in the past. No secondary line was added.
The advantage of having one safety valve in use and another as a backup is that it ensures the storage tank remains protected at all times. Not all pressure vessels need to be equipped with dual safety valves; a review of the regulations related to chlorine shows no requirement for such dual safety valves. If no auxiliary line is installed, how can residual chlorine be released to a safe place during shutdown for maintenance?
Refer to the diagram; there is a dedicated pipeline there for removing residual chlorine.
This pipeline is equipped with two valves. Is it true that dual valves are rarely used in the safety valve bypass lines? Is that why a separate residual chlorine pipeline is installed, without adding an additional line? ! !
This post was last edited by ckwcba on 2015-12-31 at 13:56. Doesn’t the pipeline behind the safety valve also need to be connected to the safety system? When maintaining and removing the safety valve or replacing the burst disc, isn’t the residual chlorine in the pipeline behind the safety valve released? Adding a secondary line is very necessary; firstly, it facilitates pressure relief, and secondly, it allows for purging with nitrogen. For the safety valve bypass, one valve is usually sufficient; it’s sealed with a lead seal and not used very often.
Well, that makes sense! It’s been thought through quite carefully, thank you! !