The resin regeneration contractor for a major electronics manufacturer and a prominent pharmaceutical maker reports that substitution of a new mixed bed ion exchange (IX) resin in both primary and secondary service has ended recurring out-of-spec episodes for their deionized (DI) water.
For the electronics manufacturer, the resin change has increased their DI water resistance from an average of 16.5 meg-ohm to consistent measurement at 18+ meg-ohm, thereby allowing them to reliably meet the specification for ASTM Electronic Grade Type I Water in their manufacturing and processing operations.
For the pharmaceuticals maker, the resin change has allowed them to consistently meet an especially low total organic carbon (TOC) specification of <50 ppb for their DI water in the process loop. The United States Pharmacopeia (USP) specification for TOC calls for <500 ppb.
"The electronics plant wasn't too pleased with the previous occurrences of low DI water quality, in the form of ups and downs, and consequent low product yield," said Dave Weatherill, principal at Regeneration Services in Burlington, ON. "Since we substituted the new resin, we hardly ever hear from them anymore. We are continuing to service their working and polishing mixed bed resin regeneration requirements, and they are consistently getting Type 1 water.
"At the pharmaceutical plant," he said, "they said they were getting over 250 ppb half the time, which was causing them shortfalls in their production. Since we substituted the new resin, they have been consistently far below their 50 ppb spec, and thereby able to reliably move forward with production schedules as planned."
At the electronics plant, the original source water for the DI process passes through 5 micron sand filtration, and is then treated with both sodium meta bisulfite (SMBS) to neutralize chlorine in the feed water, and hexa meta phosphate (HMP) to prevent scale formation in the subsequent reverse osmosis (RO) reject streams. The filtered and treated water passes through double pass RO that leaves it 99% pure.
It is then pumped from the RO storage tank to the primary (working) and secondary (polishing) DI systems, which are set up in series. Each features a tank containing a 34 cu. ft. column of the new resin. Polished water then passes through a 0.2 micron filter. A third tank, also containing a 34 cu.ft. resin column, serves as a standby unit.
After ultraviolet (UV) sterilization that feeds the DI loop, the ultrapure water is recirculated back to the storage tank at a makeup rate of 100 gpm.
At the pharmaceuticals plant, the DI water is analyzed continuously for TOC, using calibrated, certified, and validated methodology. Since the new resin was installed, readings have been consistently below 3 ppb.
Original lake source water drawn by the city passes through 60-micron disposable filters to bring total suspended solids (TSS) down to 5 ppm.
It is then pumped from a storage tank to the primary (working) and secondary (polishing) DI systems, which are set up in series. Each features a tank containing a 3.5 cu. ft. column of the new resin. A third tank, also containing a 3.5 cu.ft. resin column, serves as a standby unit. The ultrapure water is recirculated back to the storage tank at a makeup rate of 10 gpm.
The new mixed bed resin is manufactured by the Purolite Co. of Bala Cynwyd, PA, which develops, manufactures, services and supports an extensive variety of resins for a broad range of industrial applications. This new resin was among the first produced with new machinery in a specially controlled environment.
"The new manufacturing process is designed to reduce leachables to very low levels, and to eliminate microbiological contamination," said Francis Boodoo, technical director. "The ability to rinse quickly to resistivity and TOC quality standards are of fundamental importance to both the semiconductor and pharmaceutical industries.
"Particle shedding should be at a minimum, while the resins should be free of microbiological problems. We test every batch to ensure it meets our specifications for resistivity and TOC before it is released for distribution," he said.
Designated UltraClean™ UCW 3700, the new resin is described as a ready-to-use, 1:1 chemical equivalent that is highly regenerated in the H+ and OH- forms. The cation and anion are gel resins that are polymerized with a styrene-divinylbenzene matrix, and then functionalized. The resin beads effectively resist fragmentation that could result in particle release into treated water.
The new mixed bed resin is specially designed to meet key challenges for every regeneration, particularly including proper separation of cation-anion during backwashing, which is critical in preventing cross-contamination of the resin with the wrong regenerant.
Regeneration Services is a partnership of water purification experts offering water system design, service and troubleshooting. It offers consulting services for all types of ion exchange systems, as well as membrane systems.
The company can also provide independent review and validation of water purification equipment performance, and maintains several pilot system columns, with associated controls and reagents, for testing process solutions.
