Boiler water dosing guide – Aided with simulators
Boiler water dosing guide by Dieselship Academy
Master Dashboard: From daily operational checks to advanced troubleshooting and chemical concepts.
Daily Routine: The Traffic Light System
Operational Logic: Test Blowdown Dose
Step 1: Input Test Results
Step 2: Blowdown (Yellow Light)
Step 3: Dosing (Green Light)
Reason: Replace chemicals lost during Step 2. Restore reserves.
1. Alkalinity: The "P" vs. "M" Battle
Alkalinity neutralizes acid to prevent corrosion (Target pH 9.5–11). However, we must balance "Active" protection against the risk of caustic embrittlement. Use the simulator below to understand the relationship between P-Alkalinity (Primary Control) and M-Alkalinity (Total/Contamination Monitor).
Lab Simulator Controls
Target: 100–300 ppm. Measures OH⁻ & ½ CO₃²⁻.
Measures All OH⁻, CO₃²⁻ & HCO₃⁻.
Rule of Thumb
In a healthy boiler,
2 x P-Alkalinity ≈ M-Alkalinity.
System Status: Assessing...
Adjust sliders to simulate water conditions.
2. Oxygen Scavengers: The "Pit Fighter"
Dissolved Oxygen causes Pitting Corrosion[Image of oxygen pitting corrosion]—pinhole drills that destroy tubes in weeks. We add scavengers to "hunt" oxygen. Select a chemical type and adjust the reserve level to see the consequences.
Hydrazine ($N_2H_4$)
- Pro: Adds NO solids (TDS). Promotes magnetite layer.
- Con: Carcinogenic and toxic. Requires strict handling.
Simulate Test Result: Scavenger Reserve (ppm)
Guards are waiting. Oxygen is dead.
Critical Warning: If Red Iron Oxide (Rust) is found in the boiler, oxygen attack is active regardless of reserve. Investigate feed system tightness immediately.
3. Phosphate Hideout: The "Ghost" Effect
Phosphate becomes less soluble at high temperatures (High Load) and plates onto tubes, disappearing from the water test. When load drops, it returns. Don't panic dose! Use the controls to simulate load changes and observe the "Ghost" effect.
The Mistake
Engineer sees 0 ppm at High Load and panic doses. When load drops, hidden phosphate returns + new dose = Massive Spike (>80ppm).
Correct Action
If P drops at High Load: Do NOT Dose. Wait/Reduce load for 1 hr to confirm hideout. Only dose if P stays low at Low Load.
4. Condensate pH: The "Silent Killer"
Steam absorbs CO₂ to form Carbonic Acid, eating copper pipes. Volatile amines in your boiler treatment travel with steam to neutralize this. Click the nodes in the system loop to trace the path and check the pH risks.
Boiler
Amines Added
Steam Line
Amines Travel
Condenser
Acid Forms
Hotwell
TEST POINT
Hotwell Analysis (The Test)
This is where we verify if the amines neutralized the Carbonic Acid. Use the buttons below to diagnose the pH reading.
Condition: Safe Zone
Amines are effectively neutralizing acid. Corrosion is minimized.
