RE:What I ( WE) need now from rfguysd: confirmationBossu: Yes the PR report is not the same overall number as presented in the table. Let me explain without too much scientific jargon.
At room temperature(15C) propane is a gas at standard atmospheric pressure. At about 7-10 bars (7-10 x atmospheric pressure ) propane will turn into a liquid.(as in your barbecue tank). It is more efficient to ship propane in pressurized tanks in order to increase the amount of propane that can be shipped. Propane is normally shipped in pressurized railcar tanks or trucks to increase the weight of shipment.
In a the VLGC tankers, the containment tanks are not built for these pressures (10 atmospheres) to keep ship construction costs down. The route that is taken is to lower the propane temperature to a point when the propane turns to a liquid. The propane is refrigerated and stored at temperatures near -20 to -40C on the ship and at RIPET/Ferndale as well.
All gases, liquids and solids contract when they are cooled(except water).When propane is chilled to -30C, the given volume of propane for a given weight will shrink…as compared to 15C. There are correction factors to account for this volume change. I have attach a link.
https://www.ic.gc.ca/eic/site/mc-mc.nsf/eng/lm00136.html The conversion I provided was for cubic meters to barrels at the standard temperature and equilibrium pressure. This would be 15C. It appears that propane is being shipped near -30C so the conversion would be different.
To convert to tonnes directly
At 15C:
Density of propane = 500kg/m3
At -30C:
Density of propane = 560.75kg/m3
Total weight for the QTR (RIPET)= 560.75 kg/m3*656961 m3 = 368,391 tonne. For Ferndale, I would use the same assumptions and assume shipment at -30C < 2bars.
Total weight for the QTR (Ferndale)= 560.75 kg/m3*497400 m3 = 278,917 tonne. I will add a column for propane shipped (tonnes at -30C) in the next updates. I will continue to use barrels (15 C) which is standard but remember when one goes from -30C to 15C propane will expand it's volume by the correction listed on the website.
GLTA
RFguy