The following procedure describes the neutralising of LPG drums, containing a strong Ethyl Mercaptan odor, on a large LPG vessel. A dosage of 10% O-Scent in 90% water was enough to neutralise multiple drums.
Started washing empty mercaptan drums.
We took 2 empty mercaptan drums and drained with mercaptan drums all liquid until max.
After we put in the each drum 10 % “O” Scent ( 20 lit ) and 90 % water ( fresh water) and fill – up until the top from the drum ( 180 lit ) each drum.
Kept this liquid “O” Scent + water inside 5 days in the mercaptan drum ( from December 10/2019 to December 15/2019 ).
After that we transfer this mixture to other 2 empty mercaptan drums and Leave this liquid “O” Scent + water inside 7 days in the other mercaptan drum ( from December 15/2019 to December 22/2019 ).
After that we transfer this mixture to other 2 empty mercaptan drums from 22 December 2019 and at the moment the mixture is in the 2 mercaptan drums.
We use a mixture 10 % “O” Scent ( 20 lit ) and 90 % water ( fresh water) and fill – up until the top from the drum ( 180 lit) 3 times ( !! )
In the next empty mercaptan drums we will begin to use a new mixture 10 % “O” Scent and 90 % water ( fresh water).
After completed blow empty drum we checked with DRAGER tube mercaptan 20/a ( 20-100 ppm)
the result negative ZERO discoloration /ZERO mercaptan ,
thereafter we check drum’s atmosphere with more accurate scale DRAGER tube
mercaptan 0.5/a ( 0.5-5.0 ppm ) the result :discoloration corresponds to 0.4 ppm mercaptan content in the atmosphere of empty drum
Finally we checked the smell by means of breathing via nose several crew members including Ch off and Gas Eng and did not recognize any presence of Ethyl Mercaptan
We’re going to continue above procedure until deactivation odor in all empty mercaptan drums.