HEXENE 1 shipped by Sasol Alpha Olefins is extremely sensitive to oxygen and moisture. If the Oxygen content in the ullage space ia greater than 50ppm the parcel gets contaminated due to production of peroxides and carbonyls.
If the Nitrogen pad is no good the cost of removing oxygenates and water from the parcel will be on owners account. Use graphite rupture discs.
Bottom wall wash is done for Hexene 1 if the previous cargo is incompatible.
Mild pleasant odour
Uses/ perfurmes , dies, resins, polymer modifier
USCG cargo group/ 30
Marpol category/ Y
VP/ 200 mm hg at 20C
SG at 20C/ 0.673
Water solubility/ Negligible
Visc at 20C/ 1 mPas
Vapor inhalation/ dizziness and difficulty in breathing
WWT/ depends on last cargo. Sasol wants 1 ppm chlorides and PTT to hold for 50 minutes. The tank must be to methanol standards a, clean and dry.
Normally loaded in stainless steel tanks as a shippers requirement. Consult list of acceptable prior cargoes as provided by shippers.
Sasol spec is <50ppm oxygen content in ullage space. Ship must maintain gas check log and report to operator every day. All tank openings must be gas tight to prevent escape of nitrogen.
Before loading the PV valve is pressure tested to +1900 mm Aq and checked for pressure drop.at this time check all butterworth port gaskets and tank dome gaskets for leaks using a Ultraprobe.
Purge nitrogen till the dew point is -45C or oxygen content is<50 ppm inside the tank dome prior loading.
VCS is used. All tanks must be individual and not connected together .
First foot sample is taken at pump stack drain cock bt running the pump.
Tanks are filled to 98% to reduce the oxygen in ullage space.
When blowing shore line throttle the manifold valve.
Directional Rupture discs must be installed on top of PV valve with +2000 mmAq on one end and -500 mm AQ on the other branch . This is done only on completion of loading and completion of nitrogen pad with nitrogen of 99.99% purity. Between the PV valve and the discs there must be a bleeder cock to release gas pressure at regular intervals. Keep always one set rupture discs as spare. Be careful while handling the discs as they are brittle.
Use silicon tubes after loading if the gaskets of the tank do not have double defence.
During voyage maintain the nitrogen pressure of tank between 1000mm to 1500 mm AQ. When padding keep the outlet as far away from the inlet as possible to prevent short circuiting.
The voyage nitrogen log must be carefully maintained. Record every 4 hours the pressures , oxygen content, and weather. The padding times and quantity consumed must be included in the log.
STS operations and barge loadings are not allowed by Sasol.
Hexane 1 is not good cargo if the next cargo is wall wash as the UV test is affected. Use emulsifier and cold wash.
Peroxides can decompose violently and form a source of ignition.—hence blanketed with N2
CAPT AJIT VADAKAYIL ( 28 YEARS IN COMMAND )