Am I Ready for an RO Upgrade?

[SeanD]

I'm currently on a Deer Run 125 expandable and I'm wondering if I'm ready for the 250 expansion now.

This year, I have about 100 taps on vacuum, 110 on 3/16" natural vac, 50 on gravity, and a range of buckets from 12 - 30 depending on how many I feel like putting out. I average 350 gallons of raw sap per boil.

Last year I collected 3,800 gallons of sap over a month and a half. This year, I've collected that in one month and it's still going.

I've had it in my head that I'd make the jump to the 250 RO when I add mechanical vac to the 110 on natural vac, but this season has had so many mad rushes of sap at once, that even without it, I wonder if maybe I'm there already there. TO make things a little harder, the freezes have come on the weekends and the big flows have all come on weeknights.

I currently take the sap through two passes, removing 50% of the water in each pass. The first pass is somewhere around 2-3 hours depending on how much I have and the condition of the sap. I'm able to light the fire about 45 min to an hour into the second pass. On a weeknight, it would be great to get going sooner.

If I go from 125 to 250, aside from cutting the processing time in half, is it still removing 50% of the water on each pass or is that changing, too?

Input appreciated.

Thanks,
Sean

[maple flats]

With my 250 Deer Run, I remove 75% in one pass, when I run a second pass I then remove about 50% more. So if I start with 2% sap (this year it's been much lower) in one pass I have about 8% concentrate and in 2 passes I'm at or near 12%. I don't try to go over 14% because the RO membranes start to plug and I need to do a cold permeate rinse for about 5 minutes before I can resume. I don't like doing that because it is adding lots of water back into the concentrate that the RO removed once already.
Pricier RO's can get more concentration. By the way, the 2 membranes are in series.

[SeanD]

So, the 250 is doing what my 125 does right now in about a quarter of the time. Based on those numbers I would only ned to do a single pass to stay where I am now. That would save on wear and tear, too. I'm running the RO for 4+ hours on a typical boil. Longer for the big runs.

What about the slow periods? I'm boiling on a 2x6, so I try to have at least 200 gallons of raw sap before getting things going. Sounds like that would still be my threshold. What do you do during those periods at the end of the season when things are slowing down and the tank is sitting less than full in the heat? Do you boil the raw sap? What's your minimum amount to process?

Sean

[NhShaun]

Bump for the sake of curiosity.

[maple flats]

How many gph do you get on the 125 per hour and what are your outputs? My understanding was that a 125 did about 125 gph thus the model designation. My Deer Run 250 gets 250 gph, +/- about 10 gph. Much of that variation is caused by either sap temperature or/and running pressure.
What pressure do you try to operate the 125 at? On my 250 I try to hold it at 275. I start nit at about 250-260 for maybe 10 minutes, then I crank it up to 275. Then after every fueling (9 minutes) I make the rounds, I check everything on the evaporator and the pre-heater sap temp out. I used to also add 4-5 drops of defoamer (back before I had the RO I added 1 or 2 drops). As I pass the RO when making those rounds I check and adjust the pressure if needed. As I stated above, running at 275 psi I get about 250 gph thru the RO, with about 75% rejection (barely over 1 gpm concentrate and barely over 3 gpm on the permeate).
If you add a second membrane, in series with the first you will get about the same.

[maple flats]

The plumbing for that will be, pressure in the outer fitting on the bottom of the housing, then a high pressure hose out the top outer fitting, loop to housing #2 and into the outer fitting. The top of both housings will get a hose on the center fitting, for permeate. Most often it will be out the top center with an elbow, then a tee out the top center on #2 then to where it goes now (your permeate tank). If it's easier you could do it with a hose out top center on each then join them later using a tee. On the outer fittings, after housing (membrane) #2 you go to your needle valve, that is how you adjust the pressure. You will also have a smaller needle valve for recirculation, that small line goes back to the HP pump infeed. That will also affect the pressure, as you open the recirc. you need to adjust the main needle valve to keep the pressure you want.
The pressures I stated above are for when I'm right there in the sugarhouse. If I have to go get another load of firewood or anything that will take me out of the sugarhouse for more than 4-5 minutes max, I back the pressure off to about 240-250. If I need to leave longer, I only do it as it's time to add fuel, but I wait to fuel until I'm back (never more that 12-15 minutes max) otherwise I shut down both the RO and the fire. I most often boil solo.

[SeanD]

I ended up upgrading the unit this past summer - actually, Ray did it. I brought it out to him and I parlayed the trip into a stop at A and A for a couple of new tanks. It helps that I love road trips. I made the right decision to upgrade for the coming season. In addition to the vac I'm adding, I scouted out a couple dozen more taps I can add to that line. The year after I can add some more.

Ray recommended a similar process you shared - take 2/3 of the water out in the first pass. Start out at 250 psi and go to 275 psi. With the 125 unit, I usually started at 270 psi and it would naturally rise to 275 and I'd have to make micro adjustments until it stayed put at 275. After 15 minutes or so, I could walk away. On the second pass I got boiling within an hour, so I could keep an eye on it.

Ray recirculates his raw sap then sends the final pass to his head tank. That frees him up to make more runs for sap. I'm undecided. I'm set up to do either. It's easier to see the math of it all keeping the passes separate, but I'm curious about recirculating and freeing up a tank and space. I guess it will depend on how much sap I have on hand. These are good things to be wondering about. I've never gone higher than 8%. I can't imagine what 12% is like. The syrup must pour off the rig.

Sean

[maple flats]

The syrup is 50% faster. At 8% you need to boil off 10 gal of water to get each gallon of syrup, at 12% concentrate you need to remove 6.3333 gal of water for each gallon.
I noticed one advantage to going to 12% other than the boil time and fuel savings, you also make a little lighter grade syrup. Even though I sell far more dark syrup, it's still nice to have golden and amber. I do end up blending lighter with a little dark, resulting with dark, it takes little dark to darken a lighter syrup. That way I can pack for example some amber until I have what I need for a few weeks worth of sales, and I put up the rest in dark, where the bulk of my sales are, all from one barrel of syrup.
My coolers don't have enough space to pack a full barrel of each grade in a short time span. That's another reason why I'm leaning towards more 15-16 gal barrels and I'll sell some 26.5 gal barrels. Besides I've reduced my tap count, from 1320 5 or 6 years ago, to 400 this year, possibly up to 500 next year. When I was at 1320 I had 2 leases there were 7 and 10 miles away, now all taps are on my land, and vacuum brings all sap to the sugarhouse. I still have trees for about 100 more taps on my land and I have trees on the adjacent neighbor that could add maybe 75-100 more, that could also be brought direct to the sugar house.