R/O recirculating

[doocat]

Does recirculating sap through the R/O to raise to 10 or 12 % stess the membrane or cause the membrane to need to be cleaned more.

Is there any Ill effects on the R/O

Thanks
Craig

[802maple]

It doesn't require them to be cleaned more, but having said that not many sugarmakers clean there membranes enough anyway. I highly recommend that after 4 hours of processing that you rinse your membranes (with a hot water rinse if possible and followed by a short cold water rinse) after the next 4 hours the same thing and at the end of 12 hours total, if it goes that far a complete soap wash and rinse.

The only thing it stresses is the Membrane and only if you don't clean it properly. As you see in my signature, we concentrated to 24%, all six membranes that we used are now 7 years old and I don't have a idea how much sap has gone thru them. All I do know is there has been alot and when we send them up to be tested they come back at over 100% production and don't pass sugar.

[Russell Lampron]

When recirculating the only thing that you are interested in is getting rid of the water. Run the RO at a lower pressure with the permeate and concentrate flows about equal. The way I used to run my RO I would concentrate down to the level that I could get with the flow rate that would keep up with my evaporator. When I did that I was running at the highest pressure possible which hammers the membrane and slows down the permeate flow real fast. When recirculating you can set the pressure around 300 to 400 psi and let the RO run. The total output of the RO is much higher and the sap gets sweeter without hammering it.

[maplwrks]

Russ is correct, it's all about water removal. When I recirc, I worry about keeping the flow as high as I can with as low of a pressure possible. I keep my RO concentrate flow at 4-5 gpm and permeate at 12-14 gpm. I usually rinse my membranes at 4-6 hour intervals. Once I acheive the desired concentration, I crank it down to the flow of the evaporator.

[doocat]

Thanks. I'm going to try it this year but wanted reliable information before I started.

Craig

[maplwrks]

Craig--- Keep in touch, let us know how it works!

[doocat]

I will, Thanks

[sapman]

802, I've heard that the beauty of the CDL machines is that you can do a fast flow every 4 hours to wash the sugar out, so to speak. But you advocate a little more than that? On my Airablo, would you recommend following the same guidelines that you gave above? They say to do that in the literature, but I'm not sure it made much difference last year the few times I did it. FWIW, I went through a whole bottle of soap in the ten or so times I concentrated last year. Probably overkill, but I was trying to figure things out.

Thanks,
Tim

[802maple]

Tim, a membrane is a membrane and the cleaner you keep them, the better they will perform over the long haul. I say don't wait until they are failing but keep up the preventative maintainence and rinse and clean often, right Theron......

[Amber Gold]

Reading one of Theron's posts he mention recirculating 3000 gallons of sap to x number of gallons over 10 hours or something. If you're recirculating/concentrating the sap for that long of a period are you also concentrating the bacteria affecting the quality of the syrup? When concentrating aren't you supposed to concentrate, then boil right afterwards for this reason?

[maplwrks]

Josh---By recirculating back into the raw sap, you don't get a high concentration of bacteria until right up to the very end, right before you boil.If you were to concentrate all of your sap into a separate tank, and then reconcentrate, you would see a higher bacteria count due to the fact that the bacteria is sitting in concentrated sap right from the start. When Theron is concentrating all that sap, his RO is only putting out 5% concentrate. He's trying to remove 3-400 gallons of water an hour. He's putting 2-300 gallons back into the raw sap. His last 2-3 hours of concentration is when most of the high concentrate comes into play. I think, when he starts to see 15% off the RO, he's probably thinking about starting a fire. The high concentrated sap doesn't sit around long enough for bacteria to become an issue.

[Amber Gold]

Got it. Thanks.