Normal use of anion resins for condensate polishing exposes resins to the hampering effects of corrosion and organic breakdown products originating from chemical control additives and oxygen scavengers. These metals and organic materials on resin surfaces are chemically immune to regeneration chemicals, remaining on resin surfaces even after the regeneration process has been completed, making it very difficult to achieve final rinse specs.

The patented Ionx chemical cleaning process removes all corrosion products and organic foulants from resin surfaces, allowing it to be fully regenerated. Efficient and effective rinses are achievable when resins are foulant-free and fully regenerated. Information is available describing recent technical advances in safe and efficient removal of surface contaminants.

The presence of suspended metal oxides (crud) during chemical injections results in serious anion resin fouling. Iron oxides and regenerant chemicals (sodium hydroxide) combine to form highly insoluble ferric hydroxide compounds which aggressively attach to resin surfaces. Over time, resin surfaces become covered with enough foreign material that chemical contact with ion exchange sites is hindered. This physical blockage produces incomplete anion resin regenerations, excessive impurity leakage, and extended rinse times. High priority must be applied to ensuring all suspended crud is removed during the initial physical cleaning phase of the regeneration process.

Recent developments in resin cleaning technology have resulted in a chemical cleaning process that fully deconstructs ferric hydroxides, metal oxides, and organic foulants, producing resin surfaces where ion exchange sites are completely unobstructed. More information is available concerning the Ionx resin cleaning process.

The density of suspended hematite (Fe2O3 - red iron oxide) and magnetite (Fe3O4 - black iron oxide) is approximately 5.0 times greater than that of water, with the resin density itself being only 1.5 times greater. A delicate balance exists between bottom water flow rates, backwash water temperatures and densities, resin bed expansion rates, and the resulting terminal settling velocities required to flush the dense crud up through the resin charge and out to waste. Backwash flow rates great enough to flush crud out the top of a cleaning vessel will also flush large amounts of resin out to waste, or create resin pluggage at discharge screens completely halting backwash water flow. Ineffective cleaning using traditional backwash techniques requires large amounts of process waters (deionized water) to remove even a small percentage of the heavy crud from resins, leaving the majority of the crud behind.

To avoid this kind of waste generation, the Ionx cleaning process recirculates the crud-loaded resin from the bottom of the vessel up to the top and then back to the bottom, offering crud the shortest discharge path to waste. This requires very little water and places crud directly at the discharge strainer providing a much higher crud removal efficiency. The small amount of crud remaining in resins using this approach is merely dissolved by cleaning solution as iron is liberated from oxide, putting it into solution for removal to waste.

Brand new ion exchange resins are delivered to users in containers in which the resin is essentially dry, rather than in a fully hydrated state. As a result, brand new resins contain very high percentages of resin fines (broken/fractured beads). Additionally, newly manufactured cation resins contain high levels of organic chemical residues (sulfonates) as a byproduct of the manufacturing process. Sulfonates are organic and therefore do not possess ionic charges, allowing them to easily pass-through resins completely undetected. High temperature/pressure regions of the plant thermally break these sulfonates down into ionic sulfates, challenging sulfate chemistry control limits.

The Ionx chemical cleaning process eliminates resin fines that harbor residual regeneration chemicals and create a “channeling” environment within deep-bed polishers. Remaining chemical residuals left behind from manufacturing processes are also removed during the Ionx cleaning process, avoiding unnecessary challenges to chemistry control limits. The Ionx process ensures maximum resin performance for extended periods.

No, not necessarily. Decreased run-times and impurity leakage is usually the result of drifting regeneration process parameters and/or resin surface foulants which reduce resin kinetics (speed at which ion exchange occurs). Severely degraded resin kinetics/performance previously translated into discarding the resin to waste and purchase of replacement resins. An effective resin health and readiness program incorporates periodic reviews of the current regeneration process, and directs periodic resin maintenance activities designed for removing surface fouling. Extending the useful life of resin can be achieved by ensuring that resin fine levels are controlled at low levels while maintaining proper ion exchange kinetics.

Until now, there has been no viable way to chemically remove metals or organic materials from resin surfaces. The Ionx chemical cleaning process efficiently removes all surface foulants in just a hand-full of hours for each resin charge. Ask for more information about the Ionx solution for maintaining resin health and readiness while adding ten to fifteen years onto resin life.