Compare small-sized RO membrane "permeate single element recovery rates".

[Wizbi]

I have been pouring over manufacturer specs and trying to understand why AMI, Axeon, Filmtec single element permeate recovery rates differ so much for the same sized XLE membranes.

AMI XLE T2514 spec is 8%,
Axeon XLE HF5-2514 spec is 15%,
Filmtec XLE-2521 spec is 8%.

I am trying to justify procon pump volume based on needed feed flow - wanting to insure I have 2x rated flow rate as a means to keep from fouling membranes.

By using the permeate flow rate, I can calculate needed feed flow rate.
In this case, the Axeon filter would be ~2x better needing about half the input feed flow to produce the same permeate output.

Anyone have any insights as how to base comparisons?

[BreezyHill]

I think from what the dow tech was telling me about model numbers your 2514 and 2521 are different overall size branes. 2.5" by 14 and by 21".

I have an old ( 1982 Memtek) RO, & back then you ran 500-550 psi on the branes. This unit had two 4" x 40".

My pumps, a 1 or 1.5 hp centrifugal feed pump and then a piston pump ( M3 I think).

Problem was when I went to the xle branes I had to much feed rate to throttle the concentrate down to where we always ran her at. A round 2 gpm. I would start to pass sugar at this rate right away on the xles.

After talking to the Teck guy and explaining what we sugar guys do it finally dawned on him; my inflow was over the branes rate and I was forcing sugar thru due to a very low passage rate. Increased the concentrate rate to not less than 3 and all was good.

the 4040 branes are designed for only 16 gpm feed rate and I am in the mid thirties on a clean filter. So this fall...ya now...I will be putting on two more branes parallel to the two that I already have in series. Current design is a reducer out of the pump from 1" to 3/4" so I will be running 1" to a tee to the two pairs of branes that will be parallel to each other.

Currently when my branes start to foul I just increase the concentrate flow for a few minutes and we are good. The lowest pressure I can run now is around 125-130 with no restrictions; and I will run to 300 with no problems, even 450 to keep up with the flow one day.

IMO get the largest pump you can afford and be at the max flow for your branes size, plus a bit more to make up for when the filter starts to foul and you only have a few hours left to run the RO.

With an over sized pump you can always change pulleys to slow it down or if direct drive use a frequency drive to slow her down. I am adding more branes because I need more volume and I need it simple to run for the wife, sons, sons girl friends, or who ever gets to the sugar house first.

Keep this one key design parameter in mind and you will have a great system.

Mine has an auto run switch. So the operator can walk away and if anything happens like out of sap, high pressure, high temp, low pressure, leak, etc the system shuts down and a light shows the issue and an alarm sounds. I need to get a camera on it so we can check it from phones and the pc in the house someday.

Most days it is running by 10 am and runs til well after the run stops. With more branes I hope to reduce operation time and increase the sugar % to reduce boil time and wood usage.

Bigger membrane (brane) is better too. To small and you will be buying another to add in series or parallel if you have pump enough.

My size only drops 13 psi each brane so if feeding #1 at 175 then #3 should be getting around 149 psi. Plenty for an xle.

Yes I do batch if you were wondering. The system has valves for different holding tanks for feed and destination and the head tank is another destination valve.

My goal is to use not less than 12% sugar and if there is time to go to 15-18%. Some times I have to refill the head tank prior to reach goal and other times I have to suck off the nearly full collection tank to prevent an over flow. When pulling in raw sap you flush the branes very well. I found a batch tank that will allow me to run for 2 hours per batch so I can flush the branes every two hours. This should keep my efficiency up more than running for 3-5 hours on a batch.

I also made my feed pipe height adjustable so that I can test the raw sap and have the amount left in the tank so I don't get it too high on the sugar. Did that one time. Don't recommend that. Took for ever to flush the branes of the sugar and started passing a bunch of sugar too.

Good Luck! You can always add more bells and lights later as you find a need. LED strings on Ebay are really cheap and work great for low tank warnings or for near full warnings.

Ben

[Wizbi]

What components are you using for your high pressure cuttoff circuit ?

[BreezyHill]

High pressure and low pressure are in one unit with rotory selection of different pressure. One 1/8" line connects to an elbow with a threaded port.

[Wizbi]

Hi Breezy,

So that I can be clear -

I believe you are sayiong that your XLE RO setup was passing sugar because your feed rate was too high for the XLE 4040 membranes. I just confirmed the XLE 4040 designed as max feed 14gpm. You must have one heck of a pump to be pushing in excess of 30gpm. (Thats 1800gph!). That had to cause your feed pressure to be rather high also.

By opening up for more concentrate, I guess you were just letting more of the feed flow to bypass permeating the membranes. No real effect other than to mitigate a "too much" inflow problem.

Everyone I am talking to suggests that membranes are kept clean by sweeping pores with increased flow to the concentrate port. It sort of ruts out loosely lodged molecules and gives the membrane a "deep cleaning facial".

On my config, I am trying to size my high pressure pump to have slightly greater than the membrane's deigned feed flow limits. That way I can use the needle valve to constrict concentrate flow and thereby increase RO system operating pressure. Of course, one can't make the pump spin any faster than it is designed for.