Benchmark #'s and questions- how much difference between Permeate and Sap

[bmbmkr]

I bought a second or third hand DR 125 last year, it worked great and was the equalizer for us having a 22 gph evaporator and 250 taps on 3/16 on steep hills. This year I replaced the Honda gas engine and piston pump with a 220v, 1 1/2 hp and 330gph Procon and 1 HP sprinkler pump for feed. I added another vessel in series, and two brand new XLE4040's. Ran it today with permeate from last year, 36F. I used the benchmark data from the MES website. After letting about 200 gallons through, I adjusted it to 150 psi and read 3.6 gph Perm and 2.4 gpm Conc for a total of 6 gpm, which is 360 gallon per hour- I was surprised that it exceeded the HP pump specs especially with all my plumbing past the filter being 1/2". I was worried about restricting the flow.

Running with the concentrate valve wide open, I really couldn't tell what the gpm was because both meters are 0-5 gpm, and the ConC meter was pegged at the top past the scale

I did play around a little, opened the recirc valve til the main pressure came down to 100, then tightened the conc valve until HP was back to 150 psi- This gave me 0.5 Conc and 3.5 Perm. I punched these #'s into the MES RO calculator with 1.5% Sap the Conc brix should be 10%- my expectation for this machine is 8% in one pass, but if it will do 10 without plugging, I will be ONE happy sugarmaker!

I have a question for those who are running RO's, It won't matter next week because I will be running sap through it and getting what I get-so I know permeate and sap are a bit different because of the sugar/mineral content, but i can't find the %- isn't it like 10-15% less efficient with sap than water?

As soon as I get the leaks fixed, I'll be tapping

[bowhunter]

There are a lot of variables but as a general rule you will get about half the permeation rate at the same pressure on sap vs. permeate or water. So to get the same permeation rate running sap you will have to approximately double the pressure. Most membranes are rated at 100 psi.

[maple flats]

What pressure is that one rated to run at? If it is 300 max, once you get sap, try building up to about 275-280. With 2 membranes in series, if you have 275 you should get about 1 gpm concentrate and 3 gpm permeate. If yours is not rated for 300 psi, but is less than that the percentages of concentrate and permeate will be closer to equal. Does your RO have a high pressure shut off? If not, you need to either keep a closer eye on it when running or add one.
I never heard that most membranes are tested at 100 psi for rating. Maybe yes, maybe not.
As you increase the pressure the total flow will drop, your flow meters will be good. On mine with sap I get about 245-260 GPM total at about 37F, if the sap is warmer that increases and if colder it falls. When I run a permeate rinse I get 320-330 gph rate once the membrane is fairly clean.
It sounds like your's is pretty much on track.

[bmbmkr]

Thanks for the replies fellas.

My vessels are 300 PSI. I knew these numbers were going to be reduced with sap-but I sure am happy to have the larger capacity pump and second membrane. I do not have pressure switches yet. Hopefully will get those and temp shutoff plumbed in for next year. I didn't have any problems running the RO last year with out electric fail safes, kept a close eye on it. The only poblem last year was when I let my pan scorch when the ol honda ran out of gas. I was so thankful to not have that noise Friday when I did my test run. Can't beat a Honda motor, but it sure will be nice to have the RO humming on electric this year. Future upgrades will be getting the wash tank back on the machine, I didn't think the 2 1/2 gallon tank fro the 125 was going to suffice with 2 membranes, so I'm using a 10 gallon SS milk can that I'll heat permeate with a propane stove .

I really appreciate you guys helpin me with my journey through the rabbit hole. I'm headed out to tap- got 40 in last night before dark, hope to get another 150 in today.
Ben

[maple flats]

Most of all, have fun!

[DrTimPerkins]

Not exactly pertinent to the thread, but in case anyone is interested in the chemistry of sap, concentrate, and permeate.

https://www.scirp.org/Journal/PaperI...?PaperID=89798

Just came out a few days ago.