Liquid-filled capacitors are designed to produce rapid, very high voltage electrical pulses and are typically used in particle accelerators. Frequently, deionized (DI) water is the preferred dielectric, as it is environmentally safe and inexpensive to replenish, when compared with alternative fluid media, such as oils, which degrade.
A DI water system was required to service the water capacitors in a new facility at the Russian Federal Nuclear Centre – All-Russian Scientific Research Institute of Experimental Physics (part of the State Atomic Corporation ROSATOM). These high-voltage capacitors produce the burst of energy needed to create high power X-ray radiation used in radiology experiments at the Institute.
However, as the charge/discharge cycle affects the conductivity (and insulation capability) of the DI water between the capacitor plates, it must be flushed out and replaced periodically. This procedure maintains the performance level of the capacitors. Conventional water systems in this application used a mixed-bed deionization plant for the final purification stage. Unfortunately, the process required chemical regeneration of the resin beads in the ion exchange vessels and disposal of spent reagents.
Working to strict environmental safety standards, ROSATOM looked to avoid specifying equipment with such an adverse environmental impact. Consequently, the water treatment system design and build specialists, Hydrotech, proposed an alternative to mixed-bed deionization.