Evaluation of resin capacity

The following outlines a calculation method, using an example, to determine the amount of resin needed to remove an inventory of ions from a water volume.

Inputs:

— Ion exchange capacity of resin — assume a resin with a capacity of 1.85 equivalents/litre (eq/L);

— Conductivity — assume water with a conductivity of 200 μS/cm;

— Water volume — assume a volume of 10 000 litres (L).

TABLE 4. SOME COMMERCIALLY AVAILABLE CATION RESINS AND THEIR PROPERTIESa CATIONEXCHANGERESINS — RESINTECH INC. PRODUCT TYPEIONIC FORM

APPROX SHIP WT lb/cuft

SCREEN SIZE US mesh per cent WATER RETENTION Per cent TOTAL CAPACITY meq/mL (kgr./cu.ft.)

MAX. TEMP. degrees FSWELLING Per centRECOMMENDED USES CG8Strong acid gel 8% DVB

Na 52+16 <2 –50 <1 45–491.95 (42.6) 280 Na to H 5–9

Premium grade gel type strong acid cation resin suitable for softening, and demineralization, including mixed beds, dealkalization. Supplied in the hydrogen form as CG8-H. Available in black colour for easy visual separation in mixed beds.

CG8-H Strong acid gel 8% DVBH50+16 <2 –50 <149–54 1.85 (40.4)265— CG8-CStrong acid gel 8% DVB Na52+16 <2 –45 <1 45–491.95 (42.6) 280 Na to H 5–9

CG8 with coarse bead size, intended for high flow rate applications and chemical process. CG8-FStrong acid gel 8% DVBNa52+16 <2 –50 <145–49 1.95 (42.6)280Na to H 5–9CG8 with fine mesh size, intended for softening and iron removal. CGS-BLStrong acid gel (black colour)Na51+16 <2 –50 <1 49–531.9 (41.5) 280Na to H 5–12Strong acid cation resin for use in domestic softening. Specially processed to be free of colour, taste and odour. CGSStrong acid gelNa51+16 <2 –50 <1 49–531.9 (41.5) 280Na to H 5–12 CG10 Strong acid gel 10% DVB

Na54+16 <2 –50 <1 40–452.2 (48.0) 280 Na to H 4–8

Premium grade 10% DVB gel type strong acid cation resin. More resistant to oxidation than CG8. Excellent for high temperature applications, softening, deionization, and chemical processes. Particularly well suited for use in mixed beds. Also supplied in the hydrogen form as CG10-H. Available in black colour for easy visual separation in mixed beds.

CG10-HStrong acid gel 10% DVB H52+16 <2 –50 <146–532.1 (45.9) 265— SACMPStrong acid Macroporous Na50+16 <2 –50 <147–521.70 (37.2)300Ca or Na to H 4–7 Macroporous structure and high DVB level gives this strong acid cation resin the best resistance to oxidative, thermal and osmotic stresses. Also supplied in the hydrogen form as SACMP-H.SACMP-H Strong acid macroporousH48+16 <2 –50 <150–5651.6 (35.0)300—

WACGWeak acid gel (Carboxylic) H47+16 <2 –50 <1 42–494.0 (87.4) 300 H to Na 100

This gel type weak acid cation resin has nearly 100% regeneration efficiency (Carboxylic) and an extraordinary total capacity, of over 85 kilograins/cu.ft. Useful in dealkalization and chemical processing applications. Also available in the sodium form for use in high TDS softening applications.

WACG- NaWeak acid gel (Carboxylic) Na50 +16 <2 –50 <1Approx. 752.6 (43.7)300— WACMPWeak acid macro (carboxylic)H 47 +16 <2 –50 <153–58 3.8 (83.0)250H to Ca 27 High capacity macroporous weak acid cation resin with nearly 100% regeneration efficiency for dealkalization, deionization, etc., with improved physical stability. This resin is also available in the sodium form for use in high TDS softening applications.

WACMP-NaWeak acid macro (carboxylic) Na50 +16 <2 –50 <1 Approx.75 2.1 (45.9) 250H to Na 80 WACMAWeak acid macro (methacrylic) H 41+16 <2 –50 <143–533.9 (85.2) 250— Recommended for industrial and domestic softening. Has lower pH than WACMP and WACG. WACMA-NaWeak acid macro (methacrylic)Na 43+16 <2 –50 <1Approx.672.5 (54.6)250H to Na 75–100Product purification, buffering, etc. a Table courtesy of Resin Tech, Inc.

TABLE 4. SOME COMMERCIALLY AVAILABLE CATION RESINS AND THEIR PROPERTIESa (cont.) CATIONEXCHANGERESINS — RESINTECH INC. PRODUCT TYPEIONIC FORM

APPROX SHIP WT lb/cuft

SCREEN SIZE US mesh per cent WATER RETENTION Per cent TOTAL CAPACITY meq/mL (kgr./cu.ft.)

MAX. TEMP. degrees FSWELLING Per centRECOMMENDED USES

TABLE 5. SOME COMMERCIALLY AVAILABLE ANION RESINS AND THEIR PROPERTIESa ANION EXCHANGE RESINS — RESINTECH INC. PRODUCT TYPEIONIC FORM

APPROX SHIP WT lb/cuft

SCREEN SIZE US mesh per cent WATER RETENTION Per cent

TOTAL CAPACITY meq/mL (kg/cuft)

MAX. TEMP. Degrees F

TOT. REV. SWELLING Per centRECOMMENDED USES SBG1Strong base gel Type 1

Cl44+16 <2 –50 <1 43–471.45 (31.7) 170Cl to OH 18–22

Standard gel Type 1 anion resin for use in condensate deionization and single use mixed beds. Has the highest total capacity of Type 1 gel anion resins. Superior physical strength and resistance to oxidation. SBG1- OHStrong Base Gel Type 1 OH42+16 <2 –50 <153–601.2 (26.2)140 —Standard gel Type 1 anion resin supplied in the OH form for use in condensate deionization or single use mixed beds (radwaste), cartridges or single use separate beds (anion complexed metals). SBG1PStrong base gel Type 1 Porous Cl43+16 <2 –50 <1 51–571.25 (27.3)170Cl to OH 20–27Porous gel Type 1 anion resin, superior kinetics to SBG1, for use in deionization and mixed beds. Has the highest regenerable operating capacity of the Type 1 anion resins. Especially recommended for regenerable systems. Good resistance to organic fouling.

SBG1P- OHStrong base gel Type 1 porous OH41+16 <2 –50 <1 65–701.0 (21.9)

140— SBG2 Strong base gel Type 2 Cl44+16 <2 –50 <138–441.45 (31.7)170Cl to OH 10–15 Standard gel Type 2 anion resin, featuring very high capacity and regeneration efficiency. Greater resistance to organics than Type 1 resins. Excellent for two bed service. Its good regeneration efficiency and high capacity can help minimize caustic consumption and save operating costs.

SBG2- OHStrong base gel Type 2 OH42+16 <2 –50 <1 43–501.3 (28.4)

95— SBMP1Strong base Type 1 macro Cl42+16 <2 –50 <150–601.15 (25.1)170Cl to OH 15–20 Type 1 macroporous anion resin featuring high exchange capacity, porous gel matrix and superior elution of large organic molecules. Also offered in hydroxide form for immediate use.SBMP1- OH Strong base Type 1 macro

OH 40 +16 <2 –50 <1 64–73 .95 (20.8)

140 — SBMP2Strong base Type 2 macro

C143+16 <2 –50 <1 52–58 1.2 (26.2) 170Cl to OH 10-–15 Type 2 macroporous anion resin featuring high exchange capacity and superior elution of large organic molecules. Suitable for high salt content waters. Also offered in hydroxide form for immediate use.SBMP2- OH Strong base Type 2 macro OH41+16 <2 –50 <162–711.0 (21.9)140—

SBACR1 Strong base gel (Acrylic) Cl45+16 <2 –50 <1 57–621.2 (26.2) 95Cl to OH 10–15

Acrylic structure allows operating capacity and fouling resistance in applications with a high level of organics. This resin should not be used when service water temp exceeds 85 degrees F. SBACR2Strong base gel (Acrylic)Cl FB 43+16 <2 –50 <157–631.4 (30.6)95 — Acrylic resin containing a mixture of strongly basic and weakly basic exchange groups. High total capacity and resistance to organic fouling. WBG30Weak base (epoxy polyamine)CI FB 38+16 <2 –50 <152–623.0 (65.6)110FB to Cl 5 High capacity granular intermediate base resin for use in applications requiring extremely high throughput capacity or nearly 100 per cent regeneration efficiency. WBMPWeak base macroporous

Free Base

40+16 <2 –50 <1 48–541.6 (35.0) 212FB to Cl 10–15

Macroporous weakly basic anion resin, with excellent physical strength and high throughput capacity. Nearly 100 per cent regeneration efficiency and high resistance to organic fouling. WBACR1 Weak base (acrylic)Free Base44+16 <2 –50 <160–651.7 (37.2)250FB to Cl 10–15 Weakly basic acrylic resin with high total capacity, throughput capacity and regeneration efficiency. Organic substances sorbed during service are easily removed during regeneration. a Table courtesy of Resin Tech, Inc.

TABLE 5. SOME COMMERCIALLY AVAILABLE ANION RESINS AND THEIR PROPERTIESa (cont.) ANION EXCHANGE RESINS — RESINTECH INC. PRODUCT TYPEIONIC FORM

APPROX SHIP WT lb/cuft

SCREEN SIZE US mesh per cent WATER RETENTION Per cent

TOTAL CAPACITY meq/mL (kg/cuft)

MAX. TEMP. Degrees F TOT. REV. SWELLING Per centRECOMMENDED USES

First, determine the amount of equivalents of impurities to be removed in the water at 200 μS/cm conductivity. To do so, the total equivalent impurities (TEI) that needs to be removed are calculated, by using bicarbonate, HCO₃^– as reference, a mobile ion that is typically used to represent the equivalency of both anions and cations, and that presents conductivity equal to 1.72 μS/cm at concentration of 1 ppm. Using the ‘input’

information, TEI is calculated as:

(30)

which gives TEI = 19.06 equivalents of HCO3^– (eq HCO3^–).

Since the ion exchange capacity of the resin is 1.85 eq/L, the resin volume required (RVR) is:

RVR = 19.06 eq/(1.85 eq/L) = 10.3 L (31)

For a more accurate calculation, instead of using HCO₃^-, the actual equivalency of the species to be removed from the water can be used in the calculation.

A deionization system using cation and anion ion exchange resins should remove essentially 100% of the ionic impurity species from the inlet water; i.e. the outlet conductivity should ideally be that of pure water at the ambient temperature. The outlet conductivity can be used as an indicator of a resin that is approaching its capacity.

When the outlet conductivity climbs to a target value (e.g. 0.3 μS/cm) above that of pure water at ambient conditions (e.g. at room temperature, the conductivity of pure water is 0.0548 μS/cm), the resin from a deionizer system should be changed out or regenerated.