tank vents & dryers
tank vents & dryers
(OP)
I need to get a vent system for a diesel tank figured out. It's approx 300,000 gal of 5% biodiesel. The fuel is expected to sit unused for long periods of time.
The tank is 40' dia & 32' high shell. The tank will be located in a coastal marine environment.
The tank is being designed for 2.5 psig / -2 in-WC (vacuum). It's starting to look like a conservation vent and blowoff vent might do the job.
I'm worried that the conservation vent will still let in considerable moisture.
Is a desiccant vent a good idea for this?
Would a desiccant stop the ingress of salts to the tank?
The tank is 40' dia & 32' high shell. The tank will be located in a coastal marine environment.
The tank is being designed for 2.5 psig / -2 in-WC (vacuum). It's starting to look like a conservation vent and blowoff vent might do the job.
I'm worried that the conservation vent will still let in considerable moisture.
Is a desiccant vent a good idea for this?
Would a desiccant stop the ingress of salts to the tank?





RE: tank vents & dryers
RE: tank vents & dryers
The total sodium and potassium allowed in the fuel is 1 ppmw.
The fuel has 5% biodiesel which is hygroscopic. I'm still looking into what the limitations on this phenomenon are. If you have good resources/references for this, please let me know.
Nomally, a water wash of the fuel would remove the salts very effectively, but I can't say that for sure with the biodiesel.
I realize the chemistry involved here may be more appropriate for another forum.
If someone has experience with this type of storage situation, I thought this might be the place to ask.
Consequently, I wonder whether eliminating the water from air entering the tank will be a reasonable and effective way to deal with this concern.
RE: tank vents & dryers
RE: tank vents & dryers
Google still works realllly, really well...!!
https:/
Try the search terms "vent" "biodiesel" and "tank"
Have you calculated your vent massflow rate yet ?
This, of course, affects your device size and selection
Please complete this thread and let us know of your final size and selection
RE: tank vents & dryers
I've been in contact with various manufacturers of desiccant beds. I was hoping someone on this forum who has had real life experience with similar equipment would comment.
The problem isn't the existence or availability of desiccant beds. It's just that I can't find information on anything this size.
At this point, I'm moving away from this option. It's not looking very promising. I do not like the idea of putting an extra 1000 lb of media inside a vertical tank, on top of another tank, in an earthquake zone, where the benefits are not clear, and the equipment doesn't seem very common.
RE: tank vents & dryers
You can put a nitrogen or argon blanket on the tank when your are [infrequently] pumping out, at gas flowrate that gives you at net positive pressure -- no intake of moist air.
RE: tank vents & dryers
I hadn't thought of using N2 blanket as a method of moisture control.