Conductivity of water out of the final step mixed-bed is 0.056 µmhos. |
"As a result, we have not only saved more than $750,000 in the first year and over $1,000,000 in the second year in chemical costs, but also due to longer service cycle time we now need 40% less man-hours for demineralization and 20% less for DI wastewater treatment. That has allowed me to use my technicians for other analyses to help make the plant run more efficiently, while I have more time for equipment repair and maintenance."
"I have also cut water consumption for regeneration by 25%, or about 100,000 gpd, helping us to avoid a crisis in water supply for the high pressure boilers."
An IX co-flow DI system serves each of the plant's two 450 MW boilers. Each 1,005°F, 2,600 psi boiler uses 1,950 gpm of feedwater, and requires 6000 gph of makeup water. The DI systems perform eight-to-10 12,000-gal. regenerations per month, generating about 6 million gal. of wastewater that derives from DI and some polishing inside the system.
Each of three treatment trains contains three 500 ft³ cations and three 250 ft³ anions. Raw water conductivity has reached over 900 µmhos/cm. Cation conductivity is 1,400 µmhos/cm and the anion ranges from 15-40 µmhos/cm. Conductivity of water out of the final step mixed-bed is 0.056 µmhos.
Santini recalled that when shipments of acid and caustic to the plant had reached 16 truckloads per month, he was asked to investigate if it needed to be that much.
"I started consulting with our distributor, Manuel Bismarck, who had experience as a plant chemist," he said. "After he had been visited by Fabio Sousa from Purolite resins, he advised that a resin change might help. I then looked at a variety of different resins, and found them all to be the same, except for Purolite, which had a shallow shell technology."