Sodium bicarbonate (NaHCO₃, CAS 144-55-8) has gained attention in dry/semi-dry flue gas desulfurization (FGD) applications. Its primary function is to react with SO₂ and HCl in flue gas, producing sodium sulfate and sodium chloride.
Technical parameter requirements for sodium bicarbonate in this application include:
Purity (as NaHCO₃) ≥99%
Particle size: D90 ≤20μm recommended for injection systems to increase specific surface area for reaction
Decomposition temperature: begins to decompose above 50°C into Na₂CO₃, CO₂, and water; complete decomposition at 270°C
Aqueous solution pH: 8.0–8.6 (1% solution at 20°C)
In terms of operational parameters, sodium bicarbonate is typically milled to 10–25μm before injection into the flue duct. Flue gas temperature should be controlled within 140–250°C to ensure adequate decomposition and formation of porous sodium carbonate structure, thereby improving SO₂ removal efficiency. Excess dosage is typically set at 1.1–1.5 times the stoichiometric ratio.
For storage, sodium bicarbonate is stable in dry air but slowly deliquesces in environments with relative humidity ≥70%. It is recommended to use 25kg bags or jumbo bags with PE inner liners and store in a cool, dry area. Each batch should be tested for moisture content (standard limit ≤0.1%) and purity.
