Different Resin Brands

[solan]

I am trying to write a 3-year contract for the purchase of new resins for my anion, cation, and mix bed exchangers.

I currently have two issues:
1) We are very happy with the resin that we currently use, is there any technical reason that I can use to sole-source this purchase to that brand of resin? I have found an alternate resins that (on paper) are almost identical to the products we use.

2) I know mixing different brands of resin in a mixed bed is not good due to differing specific gravitites, but can you mix the brands in the cation or anion beds if they are similar? I have recieved differeing opinions.

Background:
We are treating municipal water for use in an industrial medium pressure boiler. There is nothing unusual about the water or the treatment process.

We currently use readily available, uniformly sized (Uniformity Coef of 1.1 or better) strong acid (H+) and strong base (OH) resins in our beds.

Thanks

 

[GarySCWSVI]

1) Technical reason to sole source: "If it ain't broke then don't fix it.". Alternate resins that are "almost" identical always makes me think: "Close only counts in horseshoes and hand grenades.". Many resin suppliers can duplicate their competitors, however, you need to see the complete technical specs and a Certificate of Analysis, in order to make a "change" decision. It also helps to have someone else, neither resin supplier, to confirm the quality of the alternate and the trustworthyness of the supplier. Do not switch suppliers just because of lower pricing. Lower pricing is indicative of lower quality.

2) Mixing of different brands is not a good idea. Not only from a "specific gravities" standpoint, but also from the standpoint of which in the mix is the problem. Once different brands are mixed there is no way to separate one from the other. We don't put labels or initials on each of the beads. Resins fail for a variety of reasons. When the bed fails due to a resin quality issue you will not know who to blame nor will either supplier accept blame.

Gary Schreiber, CWS VI
The Purolite Co.

 

[solan]

Gary,

Thanks for your post. It was good to hear from one of the major manufacturers.

I would love to follow your advice on not fixing what ain't broke, but unfortunately the plant is State owned. Therefore compeditively bided (i.e. cheap) is the name of the game. The trick is writing a spec that is fair and open while restrictive enough to get what you need (if not what you realy want).

One question specific to your Purofine resins.. how do you achieve your uniformity coefficient of 1.1? Is it by mechanical means or some other method?

 

[jmj5152]

Solan: I used to own a company that manufactured a counter current, packed bed ion exchange system. My experience with uniform beads has been very mixed. I have had excellent luck with companies that have a production process that produces uniform beads, but very, very, very bad experience with companies that use "screening" to achieve a uniformity coefficient. My advice...DO NOT BELIEVE THE SALESMAN! I have had to replace resins in many of my packed bed units due to continuous leaking of fines.

Demanding that the uniform beads are actually produced as uniform, would be the most appropriate technical reason to put in the specifications.

 

[solan]

Jmj, Thanks for the info. Our chemistry consultant has stated something similar, but your real world experience is usefull.

Not suprisingly, I am finding that the manufacturers literature is not terribly clear about how their products are made. Are you aware of which brands uniformly manufactured?

 

[GarySCWSVI]

My company does it both ways. Mechanical screening and jetting. Jetting produces uniform beads without screening. Typically, jetted resins are more expensive. As far as I know there are others that do the same. I believe you can get competitve bids by specifying what it is you want and then with a little research can include a list of resin suppliers that supply what it is that you want and put them in the spec as the "Only Approved" list. Whatever you do, don't just buy price.

I am disappointed to read "DO NOT BELIEVE THE SALESMAN". Granted there are unscrupulous manufactures and, yes, unscrupulous salespeople. HOWEVER, there are trustworthy manufacturers and salespeople. Without someone out selling a product where would we be today? Think about that before you put down salespeople in general.

Gary Schreiber, CWS VI
The Purolite Co.

 

[jmj5152]

Solan: My best experience has been with the R&H & Dow Resins.
I still maintain you should stick to your specs. My statement about salesman was misconstrued. Perhaps a better statement would have been to stick to the specs, and do not believe the salesman if he claims there is no difference betwen the jetted product and the screened product. Truth of the matter is, an end user such as yourself has no way of knowing the coefficient of uniformity.
GarySCWSVI, sad to say, but it was your company's claims about the uniform bead sizes I had the most problems with.

 

[GarySCWSVI]

jmj5152: Contact me privately so that we can discuss your claims about my company's claims. GSchreiber@puroliteusa.com



Gary Schreiber, CWS VI
The Purolite Co.