steam away preheater

[jrthe3]

i know there has been alot of talk about preheating sap befor it goes into the steam away has anyone had any info from this saeson sofar i was at a buddy sugar house watching the condensate roll out of the steam away at 200 plus degrees got me thinking here are my ?

is preheating sap befor it goes into steam away good or bad

would running sap and condensate threw a plate heat exchanger work to preheat sap

then do you think runing hot sap that came out of heat exchanger threw the regulor preheater in the hood cool it down or maybe run it trew the hood preheater first the into the heat exchanger then into steam away

[Brent]

I don't know anyone that bothers pre-heating before going into a Steam-Away. The condensate is mostly above 200 degrees and I don't think there's much to be gained by getting to 205 or so. A preheater on a standard evaporator only adds about 10% to the throughput, not easy to justify the expense. Better to put the money towards and RO or a SteamAway.

[sapman]

Dr. Perkins commented a little on how they went through a heat exchanger on the way into the Steamaway. Helped like 10-15% I think.

[WESTVIRGINIAMAPLER]

According to Leader they could not find any measureable difference with our without a preheater above the Steamaway.

[Brent]

According to Leader they could not find any measureable difference with our without a preheater above the Steamaway.

No surprise there, after all a SteamAway is really not much more than a preheater with bubbles.

[Dill]

Can someone explain how a steamaway works?

[Brent]

A Steamaway is a pan that sits on the flue pan. It has several large diameter copper ( more recently made with stainless ) tubes that carry the steam through them before discharging it to the hood and away. There are 4 or 5 copper tubes, 2" diameter on mine. These tubes are covered by sap. Under the copper tubes are several small diameter stainless tubes. At one end the stainless tubes are welded into a manifold. A medium high pressure blower, about 8-10" WC, blows air into the stainless tubes. There are numerous small holes on the bottom of the stainless tube, maybe 1/8" diameter. The bubbles coming out pick up humidity in a big way. The condensation in the hood and walls of the Steamaway is collected and run off. On a rig our size the condensation is about 100 gallons an hour and the sap goes to the flue pan at 200 degrees.

Not bad for the cost of running a 1/3 Hp motor.
Compared to an RO
- about the same cost to purchase
- runs 100% of the time the evaporator is boiling
- no membranes to clean/replace
- no worries about freezing
- no filters to replace
- uses 5 amps of 110V power vs 15 to 50 and more amps or 220 V for an RO
- no more flow space
- much quieter.
- like flue pan aeration or running an RO you tend to get lighter syrup.

The performance on a 2-1/2' x 8' rig dumps almost as much water as at 150 GPH RO

One the other hand you can't let it run alone at night like an RO. For a remote sugar shack with limited power like a generator, it is certainly worth consideration

[jrthe3]

so maybe there is no benifit to running the sap threw the preheater in the hood befor in goes into the steam away but it got to help having the sap at say 150 degrees as to 34 degrees befor it goes in steam away witch i think using the hot water that is comining off the steam away run it threw a plate heat exchanger and running the sap threw heat exchanger would help

[Brent]

There may be some benefit, but I think it will be very small. If the condensate that comes out of the SteamAwau is 200 degrees, then the sap is likely to be the same temp. I have not measured it yet. I may get it going later tonight and check it, but to go to the trouble of making a preheater to raise the sap coming out of the SteamAway by 5 degrees, is working against the laws of diminishing returns.

[jrthe3]

i want to raise the temp of the sap going into the steam away coming from the head tank

[Brent]

i want to raise the temp of the sap going into the steam away coming from the head tank

why ?
all the engergy that drives the SteamAway comes from waste steam that would otherwise go up the stack. The sap is as hot as it can get, just below 212 deg. The condensate comes out just below boiling.

Yeah you might get a little bit extra condensate but that's a lot of expense and trouble. Save you money towards an RO.

I'd even talk to Leader and see what they think you get out of it. You only get 8 to 10% GPH with a preheater by itself. I'd bet you'd only get a fraction of that if you already run a SteamAway.