BASIC ION EXCHANGE SYSTEM TROUBLESHOOTING

Some people thought that when their ion exchange system (softener, dual bed, mixed or polisher) does not perform according to their expectation, they simply think that the resin has a problem. More often than not, the resin is NOT the problem. For whatever reason, many service technicians blame the resin before they thoroughly troubleshoot the system. There are several accounts when unit seems to be working perfectly but the treated water is bad, they easily relate the problem with the “bad” resin. Here’s the truth. Yes, resin do fail. RESIN gets old like the rest of us. It can become fouled. But that is not a resin fault. Yes, resin beads break into fines and are backwashed out of the unit. This is not a fault of the resin because the beads are not made of steel. FOR WATER SOFTENERS – First, make certain that all mechanical components of the system are functioning properly. Easy to say, but for some reason, some people do not regularly do this in enough detail, either on purpose or due to lack of sufficient knowledge. Second, be on a lookout for a change in the feed water. Take note if your feed water is chlorinated, as this will chemical oxidize your resin. If your source is a private well, Dissolved Iron present in the feed water can foul your resin. Third, look for changes in water usage (daily water consumption or increased flow rates or leaks after the system), as your system may be treating more than it can handle. Fourth, having done all that, check how much resin is in the softener. Finally, while you are in there, take a look at the resin. How old is it? Does it appear to be mushy? Does it appear to be fouled? Is it lighter in color than it should be? Is it darker in color than it should be? The general stability of ion exchange RESIN depends on several factors. Deterioration can be physical, chemical or a combination of both. RESIN beads can crack and/or break due to OSMOTIC SHOCK – The shrinking and swelling effect resin is exposed to during regeneration and the service run. These "plastic" beads shrink during the service run and swell during regeneration. Think about that when you are bending a metal coat hanger and it finally breaks. Too high a salt dose or concentration will cause excessive swelling. Running the RESIN to complete exhaustion increases the shrinking. Fully exhausted RESIN swells faster even with a standard salt dose and concentration. Pressure on the beads caused by high feed water pressure or by excessive resin fines or sediment causing increased pressure on the beads will cause bead cracking and breaking. Broken beads (fines) and sediment if not adequately backwashed out will aggravate the condition. Chlorine in the feed water will degrade the RESIN by decrosslinking – the dissolving effect of Chlorine on the Divinylbenzene (DVB) Crosslinking in all RESIN. Iron or Manganese fouling (accumulation of Iron or Manganese within the beads will cause bead cracking and breaking. Frequent defouling procedures on the resin bed will cause damage. The list of causes of shortening of the RESIN LIFE is a long one. If all things are equal and the softener is properly operated and maintained and the feed water quality is not of a RESIN damaging nature, you should expect between Two (2) million to Ten (10) million gallons processed per cubic foot of RESIN or 10 years and longer.

Improving the Quality of Deionizers

When minerals dissolve in water, they dissociate into positively charged cations and negatively charged anions. The demineralization process exchanges these ions with hydrogen (H+) and OH– in the ion exhange resins producing "pure" water in the effluent.

Although both the cation and the anion resin are responsible for the quality of a deionization (DI) system effluent, it is the cation resin that is the big contributor to leakage. Improving the leakage characteristics of DI cation will reduce effluent conductivity, drop the pH and will lead to better silica removal efficiency.

The effluent of a dual bed DI system is generally alkaline or high pH (8.5 to 10). This is because the low pH of the cation reaction (pH 2.5 to 3.0) causes some of the residual sodium left on the resin from the previous regeneration to "leak" during the run. Sodium is the least tightly held of the cations. In the anion bed, this sodium is converted to sodium hydroxide (NaOH), which causes the high pH. One ppm of Na+ in the effluent will give a pH of about 9.5 and 4 ppm will result in a pH of around 10.0. This pH will also give rise to an increase of silica in the final effluent (leakage from the anion). It is, therefore, apparent that improving the leakage performance of the cation resin is key to overall good product quality from the system.

One way to reduce overall cation leakage is to increase the acid dosage during regeneration of the cation resin. In fact, the regenerant level is about the only controllable variable. However, there is a question in the economics for increasing the acid dose compared to the increase in capacity and reduction of leakage. Typical acid levels are approximately 8 pounds per cubic feet of resin.

Merlin TV Series Fansite - Merlin TV Show

Merlin TV Series Fansite - Merlin TV Show