Heater for LPG Liquid

[GL431]

It is late at night, eyes are getting heavy and I do not find anything on google. So I ask here.

The problem is offloading of -42°C LPG from a marine tanker to onshore storage at 500 cubic meters per hour. The storage terminal will accept LPG liquid only with approx. 3°C. A heater against seawater has been chosen. My question is whether there are also heaters against air for this duty?

The LPG is going into quite a long 10" pipeline from the jetty to storage. I would find it quite a pity that all that length could not be used to realise perhaps a finned convectional heater. Or would it have to be forced/induced draft finfan? Or a package of finned tubes stacked next to each other? I have not done any calculations yet to get an approximate size (it is late at night), so that could be the answer.

 

[GL431]

A heater against air can actually not cover the full required duty. At the location the minimum winter air temperature is 2.6°C. At these times a heater against air will not be able to heat the LPG to the required minimum storage temperature and sea water (min temperature 16°C in winter) will be needed. But what about splitting the duty so that in summer a heater against air would be sufficient and in winter the heater against sea water will assist?

You can see that I am trying to minimise the trouble I expect to see with a heater against sea water.