Ship loading temperature

[essenwood]

Hi all,
Had this debate with my oil movements and ship people.
Why is it that most petroleum product ships (eg fuel oil) dictate that they can only receive the product at max around
160 deg F to 170 deg F (the rest of the world around 70 - 75 deg C). I can understand the minimum temp but the max tempe requirement?
We thought it couldn't be safety related,as water boils at higher temp. We thought also maybe, this is the ship people way of making sure that the load port and outturn volumes are close; i.e everyone using the same temp as the reference. Any ideas?

Thanks.

 

[25362]

My guess is the limitation may be related to either of two factors:

a. One reason may be the fuel's flash point. As we all know the flash point is the temperature to which the fuel must be heated to produce an ignitable vapor-air mixture when exposed to an open flame. Flash point is used primarily as an index to fire hazards.

I think the minimum flash point for heavy No. 6 fuel oil is 60^oC = 140^oF. Thus, if flash points are indeed the reason, even the maximum temperatures you quoted seem to be a bit on the high side.

b. Another possible reason I could see may be to minimize emissions in the port area.

Why not ask the ship people and clarify the issue for all of us to learn ?

 

[bimr]

It is probably because the cargo tanks and cargo tank relief venting systems are rated for low pressures, say 1 psig. As the temperature of the petroleum product increases, the vapor pressure increases.

 

[121202]

The limitation is generally based on tank coating limitations. Crude tankers for example can rarely accommodate temperature much greater than 65-70 deg C.

Rgds

 

[essenwood]

Guys,
I will indeed post the clarification when I get them. Will talk to the Captain soon. We tried once to have the product temp raised from 70 deg C, and the Captain waivered the requirement to 75 deg C. I thought I did some homework first before asking the Captain how he got to the 75 deg C.




Thanks