Boiler Water Dosing System: Automatic Chemical Feed

Boiler water chemistry decides whether a boiler runs a full campaign or loses tubes to scale and oxygen pitting. Manual batching drifts; an automatic dosing system holds the setpoint.

The Operating Reality

A steam plant feeds oxygen scavenger, phosphate and alkalinity control into the feedwater and boiler drum. Load swings change blowdown rate, so the required dose changes hour by hour.

Why Manual Dosing Falls Short

Manual dosing typically wastes 15-25% of chemical and reaches only 65-80% concentration compliance. Automatic feed cuts waste to 2% or less and lifts compliance to 98% or higher, which is what protects the tube bundle.

How Automatic Chemical Dosing Fits

• Metering is done by imported plunger pumps at ±0.5% accuracy (national standard allows ±3%), with pulse rates above 5000 per minute for fine control at low dose.
• Dose is driven by live water-quality signals, not a fixed timer, so blowdown swings do not push chemistry out of band.
• Dry-running protection and a leak alarm within 2 seconds protect the pump and the plant floor when a drum or tank runs empty or a line fails.

Selection Checklist

• Define the control signal first (pH, ORP, conductivity or flow-proportional) before sizing the pump.
• Size the metering pump to the lowest expected dose with margin, not to the peak dose.
• Confirm chemical compatibility of wetted parts (316L, PVC, PVDF) with every product to be fed.
• Provide containment, leak detection and dry-running protection in the dosing room design.
• Integrate the skid with PLC, DCS or remote telemetry so dose is visible in the control room.

Related Products

• Automatic Chemical Dosing System
• Automatic Condenser Tube Cleaning System (ATCS)
• Constant Pressure Water Make-up System

FAQ

Related Dosing Guides

• Corrosion Inhibitor Dosing System
• Scale Inhibitor Dosing System
• Chemical Dosing System Working Principle