Mixed bed ion exchanger water treatment plant ion exchange resin filter (FISD)

Mixed bed ion exchanger water treatment plant ion exchange resin filter (FISD)

Purpose. Mixed-bed ion-exchange filters (FISD) are designed to remove Na+, K+ cations and silicic acid anions from the incoming flow as the final stage of water desalting. The produced deeply desalted water is most often used as makeup for steam boilers (medium and high pressure steam generation). FISDNr filters are also used for afterpurification of turbine condensate. The FISD filter is filled with the rated amount of mixed cationite-anionite charge. Water after deep ionite treatment is mostly used in various industrial technologies that require ultra-pure water in large quantities. One FISD filter can replace two series-connected H- and OH- ion-exchange filters

Ion-exchange materials of natural and artificial origin, such as cationites and anionites, are used as the filtering media in ion-exchange filters.

Design description. Mixed-bed ion-exchange filters FISD consist of:

• housing;
• inspection windows;
• upper and lower distribution devices;
• piping;
• stop valves;
• sampling devices.

FISD filter housing is cylindrical, welded of sheet steel, with welded elliptical stamped bottoms. Three supports are welded to the bottom for mounting the filter on the foundation.

Upper and lower bottoms have flanges welded in the center, to which outside along the filter front – pipes are to be connected, and inside – collection-distribution devices (NRU and VRU).

Upper collection-distribution device of the "cup-in-cup" type and lower collection-distribution device of the duplicating type "spider" with stainless slot caps FEL are most often used for FISD filters.

A medium collection-distribution device (USSR) of stainless steel for the separation and regeneration of ion exchange resin is provided for FISDVr filters.

Operation principle. The FISD filter cycle consists of the following stages:

• water desalting (filtration);
• backwashing and separation of cationite-anionite charge;
• regeneration (inside the filter or remote);
• cleaning;
• mixing of ionite charge;
• discharge of the primary filtrate before it is put into the scheme.

Operation principle of FISDVr filter

The incoming flow under pressure enters the upper collection-distribution device of the FISDVr filter, is evenly distributed and passes through a layer of mixed cationite-anionite charge downwards. Na+, K+ cations and silicic acid anions are kept in the grains of the material, providing a deeply desalted filtrate, which is discharged from the filter to the collector through the lower collection-distribution device.

Backwashing (separation) of ionites is performed upwards. The result of separation of cationite and anionite is observed visually through the inspection windows. Regeneration of ionites with alkali solution and acid solution can be performed simultaneously or alternately. Ionite cleaning is performed with deeply desalted water in the direction of the regenerant solutions flow. At the end of cleaning, the ionite charge is mixed with compressed air. At the end of cleaning and mixing, the filter is switched on or remains in standby mode. Right after the filter is switched on, the first portion of the filtrate is discharged into the drainage and analytical control is performed. After getting the regulatory figures for the deeply desalted water, the FISDVr filter is connected to the filtrate collector.

Operation principle of FISDNr

The filter cycle consists of the following stages: deep desalting, stopping for regeneration, hydraulic reloading of ionite charge into the regeneration filter (FR), hydraulic reloading of regenerated ionite charge from FR filter, mixing of ionite charge, cleaning of ionite charge. Deep desalting (desilication) occurs when the incoming flow passes through a layer of mixed cationite and anionite.

Hydraulic reloading of the used ionite charge is performed by water pulp into the regeneration filter at the speed of 0.5 m/s (one regeneration filter is used for a group of three FISDNr filters). Hydraulic loading of the regenerated ionite charge is performed by water pulp from the regeneration filter. The next stage is mixing the ionite charge with compressed air. Ionite cleaning is performed with deeply desalted water downwards. Right after the filter is switched on, the first portion of the filtrate is discharged into the drainage and analytical control is performed. After getting the regulatory figures for the deeply desalted water, the FISDNr filter is connected to the filtrate collector.

The FISD filter operation cycle ends when the content of Na+, K+ cations and silicic acid anions in the filtrate approaches the maximum permissible values.

Specifications. Material of FISD filter housing: stainless steel, carbon steel, low-alloy steel, plastic (polyamide 6, reinforced polyester).

Material of internal devices: stainless steel 12H18N10T, 03H17N14M3 or 10H17N13M2T, PVC, CPVC, polypropylene, PVDF, titanium.

Diameter of the housing of the manufactured FISD filters varies from 2000 to 2600 mm, capacity of the devices: from 300 to 380 m³ /h, working pressure: from 0.6 MPa to 1.6 MPa.

Protective coatings. A special anti-corrosion coating is applied to the filters’ inner surface, which contacts the working medium. The type and brand of coating is selected depending on the characteristics of the aggressive environment (epoxy, polyurethane, gumming with rubber, preserving primer, etc.). At the request of the customer, any coating available on the market can be applied.

The outer surface of the filters is coated with standard priming enamel. At the customer’s request, the outer surface can be painted in corporate colors and with the use of special protection against corrosion (ROSNEFT, SIBUR, GAZPROM, LUKOIL, etc.).

Product range and specifications of manufactured mixed-bed ion-exchange filters (FISD)

Mixed-bed ion-exchange filters FISD have a number of advantages:

• High mechanical strength. All filter models undergo strength calculation, the results of which are attached to the certificate.
• Long-term trouble-free operation. The internal design of the filters is unique development of our company. They have been effectively used at many sites for more than 25 years.
• Production by individual order or technical specification of the Customer. Any packaging arrangement and design of filters according to customer requirements is possible.
• Quality assurance from the manufacturer. All technologies, equipment and personnel at the enterprise are certified in accordance with the requirements of regulatory documents of the Russian Federation. All materials undergo incoming inspection and testing.