Concerns about stratification with solid feedstocks and blocked drain valves?

[julianf]

My plan was -

• 205ltr drum
• with cone bottom
• with copper heating coil from domestic hot water tank

But -

• The coil will never go right to the base of the cone
• I have solid feedstock

I cant work out what my best plan is?

What i want is a tank where i can leave the solids, and gently heat / settle with hot water from my bio-boiler.  I dont want to pump the feedstock at all, as that will stop the water etc. settling out.


I could just install the coil in a standard, flat bottomed, drum, and put two ports in the side - one for draining the water (at the same level as the heating coil) and the other for taking the feedstock (a bit higher up) but this would mean that my drum will *always* have a layer of water at its base, that i wont be able to get rid of.  I dont know if this really matters?


The only other thing i can think of is having some sort of double skinned cone, with water in the middle.  But construction of that is going to be somewhat involved : (


So -

a) Im pretty sure im right in that a cone bottom solids tank is not the best idea, right?
b) Whats my next best option?

[Maurice_Mynah]

If I understand your objectives correctly, Would it be possible to have two cones of different angles, welded together creating a jacketed cone with the hot water in the jacket?

[julianf]

Yep, that would be perfect - if it were not for the fact that i think id have trouble making it.

(i dont have a welder, and, whilst i can attempt to weld stuff, im only a beginner)

[Maurice_Mynah]

And I always thought you were a man of the weld!
OK, thinking cap back on!

[Tony]

Could you wind microbore copper around the outside of the cone, silver soldering it to the cone itself for heat transfer?

[Julian]

Make your own, vertical, annular heating coil using 180° bends (available from BES) or two 90° and a copper tube bender.  That way you could arrange a concentration of heat near the bottom of the cone.

[julianf]

Make your own, vertical, annular heating coil using 180° bends (available from BES) or two 90° and a copper tube bender.  That way you could arrange a concentration of heat near the bottom of the cone.

I did strongly consider that before.  It would only need a little heat down by the drain valve - im not needing to melt the whole drum from that point, just stop the port from blocking.

But then i also remembered how easy it is to block the drain port on my reactor with glycerol etc.  The idea is a contender, for sure.

Could you wind microbore copper around the outside of the cone, silver soldering it to the cone itself for heat transfer?

That might be an idea also.  As above i wouldnt need much heat.


Another possible idea i had was -

Make a cone, but, instead of putting it on the outside of the drum (with the base cut out) put it on the inside (with the base still in place)

The volume of the drum would be that much less, but id get a built in stand.


I think the cone in cone idea is the best though.  That way i wouldnt have to use a coil at all, and the drum would be easier to clean out then too.

[Dickjotec]

Julian
If it is any help you may remember my solid heating tank? It is just a hot water cylinder with the top cut off. I have added a water drain tap at the bottom and the oil comes out of what was the cold feed. The bottom tap is not heated but once it is up to heat there is enough heat transferred to enable oil to flow out. The oil tap is heated with a piece of tube that runs round it.
I drain the water daily and it works well. It is heated with hot water through the coil.
In your case why not use a shallow cone or even just a dome like RM did with his dome tool? The tap only needs to be at the lowest point so all the water comes out.
Dick

[1958steveflying]

James RL makes a nice twin walled cone tank, I have one.