Demineralization Calculators

Total Cation Load: TCL = Ca + Mg + Na + K (mg/L as CaCO₃)

Service Volume: V = Q(GPM) × t(hr) × 60 (gallons)

Cation Load: Load (kgrains) = V(gal) × TCL(ppm) / 17,120 — 1 grain/gal = 17.12 mg/L

Resin Capacity interpolated from regenerant level: HCl @ 10 lb/ft³ → 21 kgr/ft³; H₂SO₄ @ 8 lb/ft³ → 17 kgr/ft³

Required Resin Volume: V_resin (ft³) = Load / Capacity

Vessel Diameter: Target SLR 8 GPM/ft² → area = Q/8; round up to standard diameter (1.5, 2, 2.5, 3, 4, 5, 6 ft)

HCl 31% consumption: gal = lbs_100% / 3.0 (3.0 lb HCl/gal at 31% → SG 1.16)

H₂SO₄ 93% consumption: gal = lbs_100% / 14.17 (SG 1.83)

Total Anion Load: TAL = Cl + SO₄ + HCO₃ + (SiO₂ × 1.667) + NO₃ (mg/L as CaCO₃)

SiO₂ conversion: SiO₂_equiv = SiO₂_ppm × (50/30) = SiO₂_ppm × 1.667

Capacity: Type I @ 8 lb NaOH/ft³ → 18 kgr/ft³; Type II → 20 kgr/ft³. If silica >20% TAL: apply 0.85× (Type I) or 0.70× (Type II) efficiency factor.

NaOH 50% consumption: gal = lbs_100% / 6.38 (SG 1.53 → 6.38 lb NaOH/gal)

Vessel sizing: same SLR approach as SAC calculator (8 GPM/ft² target).

Effluent Quality: From influent <50 µS/cm → ≤0.1 µS/cm (10 MΩ·cm); from <5 µS/cm → ≤0.055 µS/cm (~18 MΩ·cm). Pure water at 25°C = 0.0551 µS/cm = 18.18 MΩ·cm.

Mixed Capacity: C_total = SAC_vol × 21 + SBA_vol × 18 kgrains (at typical regeneration levels)

TDS Equivalents: TDS_kgr/gal = TDS_ppm / 17,120

Service Volume: V_svc (gal) = C_total / TDS_kgr_per_gal

Run Time: t (hr) = V_svc / (Q_GPM × 60)

CO₂ from SAC effluent: CO₂ = Alk (mg/L as CaCO₃) × 0.44 — at SAC effluent pH ≈ 3–4 all alkalinity converts: 1 meq HCO₃ = 22 mg CO₂

Henry's constant (dimensionless): H_cc(T) = 0.83 × exp(0.021 × (T_°C − 25))

Stripping factor: S = H_cc × A:W

NTU: NTU = ln[(CO₂_in/CO₂_target) × (1 − 1/S) + 1/S] / (1 − 1/S)

Packing height: Z = NTU × HTU where HTU = 2 ft (1" Pall rings)

Air flow: Q_air (SCFM) = Q (GPM) × 0.134 × A:W

Tower area: At 150 ft/min air velocity → A = Q_air / 150; D = √(4A/π)