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Rocket Heater - 6,000 Gallons Vegetable Oil  RSS feed

 
Posts: 4
Location: Foothills of Appalachia
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Ello...,

I goht ah prahblem.

Need to heat 6,000 gallons of Used Cooking Oil (UCO) to 90*F in ~48-72 hours, then boost the temp to ~100*F in another 24 hours, all in preparation of shipping. 3.2 million btus initially, at 100% efficiency (Hah!), with a flash of 700,000 btus thereafter Hah! Hah!). Storage is ambient temp, currently approximately (~)20*F. (Final storage, as well as shipping tanker, IS insulated.)

NG is out of the question as the draw would shut down other users on the same rural line. Besides, we have tons of wood chips on the back 40 from a local line clearing service.

Would like to create a rocket similar to Ernie & Erica's Okanagan Highlands mass heater, but different, as I'd be heating liquid, and creating some conduction modifications. And I'd also like to utilize the wood chip biomass 24/7, with a continuous feed of chips...

The rough "visual" follows: Ten 550 gallon HDPE tanks, all with 2" outlets manifolded into one 2" line. Run manifold's outlet line to Rocket, through a "heat exchanger," and back to tank. Repeat for each tank until all 10 have been pre-heated to 90*F. Repeat process for ~ 10*F boost.

Would appreciate input on the following: At the rocket, split the 2" line into four 1" lines. Run one 1" line (with 180* sweeps at each end) vertically like Christmas ribbon candy on each 90*s of the 55 gallon drum's radius. Four 1" feed loops all plumbed back into to a 2" return manifold. Tighten the 1" pipe to the drum with metal banding strap. To improve conduction, put ~12" long inserts of ~1" aluminum U- or C-channel between the pipes and drum, in between each rib on the drum, before tightening with metal strap. Wrap rocket and "heat exchanger with 12" aluminum flashing (radiant barrier). Wrap with 6" of rock wool. Put a sheet metal skin on it to protect surface from clumsy persons (such as myself, upon occasion).

Utilize the 2' in diameter drum top for further heat exchange..., somehow... (keep me tea and crumpets warhm...)

This is my first go at a rocket. Can't afford expensive. Can't afford failure.

Suggestions...?

 
pollinator
Posts: 4154
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
59
books fungi hugelkultur solar wofati woodworking
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Walt Thornwald : Donno! You are definitely breaking new ground here, I have some experience with Biodiesel and various pour point depressants to help
keep these oils flowing when it gets cold !

My grandmother had a Summer recipe for molasses cookies, and they jug went glug, glug, glug! And then she had a winter Recipe were the jug went
ga-lug - - - ga-lug! Right now, any where around here fighting the thick as molasses Viscosity of your Used veg oil would make a saint cry - Where are you
located ?

From what I have learned, I would try filtering small batches of your oils, starting with th clearest, and discarding all that are really dark.

The best advice I have for you is Don't Follow or pay any attention to the Piles of stinking Crap on U-tube, there truly is a lot of Garbage there.

This is where I recommend that you go to tp Download a PDF Copy of Rocket Mass Heaters with over 100,000 RMHs build world wide this is " The Book"
95% of all the 1st time builds (that worked) were made from the pages of this book.

Get the book, read the book, and try a few test models outdoors to prove to yourself that these rockets do Indeed work. After it warms up will be soon
enough to tackle making what you have flow.

Sorry I could not be more positive, hope this helps a little ! Big AL
 
Walt Thornwald
Posts: 4
Location: Foothills of Appalachia
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Allen,

It's just an overly-over-glorified H2O heater, eh?

Location is SE Ohio. The UCO is already de-watered, filtered and ready to hit the feed line of any biodiesel plant. Unfortunately the "suits" at some of these facilities have their knickers in a knot over incoming feedstock that's not Goldilocks' "just right," and are beginning to decline shipments of UCO upon arrival.

So, in part, while this inquiry may seem to be appropriate for a "biodiesel forum," me thinks the unconventional heating experts might be more inclined to "slum" in the rocket forum.

No html embedded in your Rocket Mass Heaters link. I did find RMH books at www.rocketstoves.com by Googling a few of the words after the faulty link.

No doubt part of this will be trial & error. Only room for one or two errors. Hopefully enough variable controls are built in to quickly adjust to any "errors," such as, "what if the cold oil flow is too great a volume and too much heat is sucked away from the barrel?"

After all, this is essentially a RMH without the M, unless you consider the veg oil the "M."

So technically it's a RHE (Rocket Heat Exchanger)?

Still fielding suggestions...
 
gardener
Posts: 2581
Location: Upstate NY, zone 5
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Does the oil currently flow well enough to get from the tank to the heater to start with? If so, your design sounds workable. I might make the 1" pipes straight from manifold at bottom to another manifold at top, so the oil will want to flow in the right direction naturally. A pump can boost the speed as desired. How close together are the tanks? Will you be able to put the heater in a spot convenient to all of them, or does that not matter?

The barrel of an RMH can get to 500 f or more at the top of the sides, so be sure you can keep the oil moving fast enough to not overheat.
For best use of the heat generated, you might want to add another barrel on top of the first (open ends together) to make a 6' tall bell. This would give much more dwell time for the hot gases to give up heat to the oil, and double the exchanger pipe length without doubling the work to build it.

Taking heat from the exterior barrel will not hurt the function, as long as the internal heat riser gets freaky hot as designed. Once the gases exit the riser, their sole function is to give up the heat that has been generated.
 
Walt Thornwald
Posts: 4
Location: Foothills of Appalachia
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Gravity feed assist on all tanks @ approximately 4' of head pressure to the top of RMH. UCO will move s-l-o-w-w-w-w-w-w-l-l-l-l-l-l-l-y-y-y-y-y-y-y on its own. Positive displacement pump (gear) will create further vacuum/pull.

Might have to focus a torpedo heater at the exit valve on the occasional tank to help initial flow. Maybe preheat the feed line to the RMH. Will have ~400 gallons of 90-100* F oil on hand to "get the ball rolling."

Return line will be dipped to the bottom of each tank close to the exit valve. This should heat tank's contents from the bottom up. Move upward as tank warms. Slightly defeats previous head pressure gain by doing so, but that negative comes after the pump rather than before.

Would tend to believe it to be more energy efficient to return oil to the bottom of the tank and let warm oil shed its heat upward into colder oil.

Slightly warm oil getting to the pump's intake faster and continually also cuts down the amperage being drawn.

RMH can be located almost perfectly equidistant from all tanks. Maybe 25' from the furthest two.

Increase the RMH's riser height the same as the internal height of the second barrel, yes?

Rather like the idea of longer heat exchanger pipes. 180* sweep widths definitely restrict the number of exchanger tubes around the barrel's circumference. Aluminum U- or C-channel between drum ribs would need to be tall enough to allow exchanger tubes to pass over the lock-ring used to connect the two barrels.

That could be a $100.00 + mistake before ever getting out the door...

When all is said and done (Like this is gonna' be easy?), maybe build a 48' x 32' building around the stove some year in the future, rather than move it. Move all the tanks into a properly insulated structure where the temp rise will only need to be maybe 50*F next winter, rather than 70-80*F. (Why heat what's not being used?)
 
Glenn Herbert
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Posts: 2581
Location: Upstate NY, zone 5
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The double barrel bell would just give lots of space above the riser for hot gases to accumulate. The riser would stay the same length as usual. Look for Peter van den Berg's three-barrel bell in the forum at donkey32.proboards.com. He used a batch box, but you could just as easily use a J-tube combustion core.
 
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what if you wrapped 4 lines of 1" copper around the barrels and insulated that all (increase surface area)? then pump your oil around the barrels and back up to the tanks? you could tie into a manifold after its heated to lower surface restiance then branch off with separate pex lines to dump into your tanks.

the 6' barrels seems like a great idea to me, you could even put the cooling fins for refrigeration units on the copper to act as a heat collector and run coils of it on the inside of the barrels to further increase your pickups. Anyone else have ideas on the practicality of that?



or instead of dumping the oil into the tanks use the fins again to run a coil through the tank The cool oil in the tank will take the heat away and disperse it automatically. this reduces the amount of restiance of your product going to and from the rocket heater as it is flowing like hot deep fryer oil
 
Glenn Herbert
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Posts: 2581
Location: Upstate NY, zone 5
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No liquid-filled coils inside the barrel - the temperatures are so high near the top that most anything will boil or flash to vapor when surrounded by 600-1000 degree f gases. It would even be important to keep the exterior coils/pipes a bit away from the barrel at the top.
 
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