Advanced Boiler Water Treatment System
Compliant with water quality standards and sampling protocols (EN 12952-12 and ISO 5667)
Water Pretreatment
Select the method Pretreatment according to the boiler type and feedwater quality.
Detailed Comparison Table: Boiler Feedwater Quality
| Parameter | ✅ Good Quality | 🟡 Medium Quality | ❌ Poor Quality | Measurement Method | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Optimal | Acceptable | Limit | Upper | Typical | Lower | Moderate | High | Extreme | ||
| Conductivity (μS/cm) | < 100 | 100-150 | 150-200 | 200-300 | 300-400 | 400-500 | 500-1000 | 1000-2000 | > 2000 | Conductivity Meter |
| Total Hardness (ppm CaCO₃) | < 0.5 | 0.5-0.8 | 0.8-1.0 | 1.0-2.0 | 2.0-3.5 | 3.5-5.0 | 5.0-10 | 10-20 | > 20 | EDTA Titration (ISO 6059) |
| Silica (SiO₂) (ppm) | < 0.5 | 0.5-0.7 | 0.7-1.0 | 1.0-1.5 | 1.5-2.5 | 2.5-3.0 | 3.0-5.0 | 5.0-10 | > 10 | Spectrophotometry (ISO 16264) |
| Alkalinity (ppm CaCO₃) | 30-50 | 50-70 | 70-100 | 100-130 | 130-170 | 170-200 | 200-300 | 300-500 | > 500 | Acid Titration (ISO 9963) |
| Turbidity (NTU) | < 0.5 | 0.5-0.7 | 0.7-1.0 | 1.0-2.0 | 2.0-3.5 | 3.5-5.0 | 5.0-10 | 10-20 | > 20 | Nephelometry (ISO 7027) |
| Solids Suspended (ppm) | < 0.5 | 0.5-0.7 | 0.7-1.0 | 1.0-3.0 | 3.0-6.0 | 6.0-10 | 10-20 | 20-50 | > 50 | Filtration/Gravimetry (ISO 11923) |
Comparison Table: Makeup Water Quality
| Parameter | Quality Levels | Measurement Method | ||
|---|---|---|---|---|
| ✅ Optimal | 🟡 Acceptable | ❌ Unacceptable | ||
| Conductivity (μS/cm) | < 50 | 50 – 200 | > 200 | Conductivity meter |
| Total Hardness (ppm CaCO₃) | < 1 | 1 – 5 | > 5 | EDTA certification (ISO 6059) |
| Chlorides (ppm) | < 10 | 10 – 30 | > 30 | Titration with AgNO₃ (ISO 9297) |
| Silica (SiO₂) (ppm) | < 1 | 1 – 3 | > 3 | Spectrophotometry (ISO 16264) |
| Turbidity (NTU) | < 0.5 | 0.5 – 1 | > 1 | Nephelometry (ISO 7027) |
Pretreatment Options
| Method | Description | Recommended Pressure | Effectiveness |
|---|---|---|---|
| Multimedia Filtration | Removal of suspended solids (>5 μm) | All | High |
| Reverse Osmosis | Removal of 95-99% of impurities | Medium and High | Excellent |
| Ion Exchange | Water Softening | Low and Medium | Excellent |
| Deaeration Thermal | Dissolved Oxygen Removal | All | Critical |
| Magnetic Descaling | Crystal Structure Modification | Low | Moderate |
Advanced Technologies
Reverse Osmosis
Semi-permeable membrane system that removes ions, molecules, and particles from water.
Efficiency: 95-99% reduction in dissolved solids
Pressure: 150-1200 psi
Electrodeionization (EDI)
Combines ion exchange membranes with electric current for continuous demineralization.
Advantage: No need for chemical regeneration.
Vacuum Deaeration
Efficient removal of oxygen and other dissolved gases through pressure reduction.
Residual O₂: <7 ppb
Cost Analysis
| Technology | Initial Cost | Operating Cost | Useful Life | ROI |
|---|---|---|---|---|
| Multimedia Filtration | $5,000-$20,000 | Low | 10-15 years | 1-2 years |
| Reverse Osmosis | $50,000-$200,000 | Moderate | 7-10 years | 3-5 years |
| Ion Exchange | $30,000-$100,000 | High (chemicals) | 10-15 years | 2-3 years |
Internal Boiler Water Treatment
Select internal treatment chemicals based on your boiler’s needs.
Comparison Table: Boiler Water Quality
| Parameter | Operating Pressure Ranges | Measurement Method | |||
|---|---|---|---|---|---|
| ≤30 bar | 30-60 bar | 60-90 bar | >90 bar | ||
| Conductivity (μS/cm) | ≤5000 | ≤3000 | ≤1000 | ≤500 | Conductivity Meter |
| pH (25°C) | 10.5-11.5 | 9.5-10.5 | 9.0-10.0 | 9.0-9.5 | Thermal Compensated Electrode (ISO 10523) |
| Phosphates (ppm PO₄) | 20-40 | 15-30 | 5-15 | 2-10 | Spectrophotometry (ISO 6878) |
| Silica (ppm SiO₂) | ≤150 | ≤50 | ≤20 | ≤2 | Spectrophotometry (ISO 16264) |
| Dissolved Solids (ppm) | ≤3500 | ≤2500 | ≤1500 | ≤500 | Gravimetry (ISO 9963) |
Internal Treatment Options
| Category | Product | Mechanism | Dosing Limits |
|---|---|---|---|
| Scale Inhibitor | Ortho-Phosphates | Controlled Precipitation | 20-40 ppm PO₄ (low pressure) 5-15 ppm PO₄ (high pressure) |
| Polyphosphates | Ion Sequestration | 10-30 ppm (low pressure only) | |
| Phosphonates | Crystal growth inhibition | 2-10 ppm (all pressures) | |
| Dispersants | Acrylic polymers | Particle dispersion | 5-20 ppm |
| Lignosulfonates | Dispersion and chelation | 10-50 ppm (low pressure only) | |
| Copolymers | Multi-action | 2-15 ppm | |
| Control of pH | NaOH | Alkalinity Adjustment | pH 10.5-11.5 (low pressure) pH 9.0-10.0 (high pressure) |
| O₂ Scavenger | Sodium Sulfite | Chemical Oxygen Removal | 20-50 ppm (residual SO₃⁻) |
Pressure Treatment Programs
Low Pressure (<600 psi)
- Phosphates + Dispersant Polymers
- pH Control with NaOH
- Sodium Sulfite for pH Control O₂
High Pressure (>900 psi)
- Organic Phosphonates
- Advanced Copolymers
- Precise pH Control
- Volatile Products for O₂ (DEHA, Hydroquinone)
Dosing Calculation
Corrosion Control and Prevention
Configure parameters to prevent different types of corrosion in the boiler system.
Acid Corrosion
Caused by: Presence of CO₂ forming carbonic acid (H₂CO₃) or acidic contaminants
Recommended Treatments
| Product | Mechanism | Dosage | Effectiveness |
|---|---|---|---|
| Neutralizing amines | Raise condensate pH | 3-10 ppm (pH 8.5-9.2) | Excellent |
| Morpholine | Volatile Neutralization | 2-8 ppm | Excellent |
| Cyclohexylamine | Vapor Phase Protection | 1-5 ppm | Good |
Oxygen Corrosion
Danger: Dissolved oxygen causes localized pitting that can rapidly weaken the metal
Oxygen Control Treatments
| Product | Mechanism | Pressure Range | Dosing |
|---|---|---|---|
| Sodium Sulfite | Direct Reaction with O₂ | <600 psi | 8 ppm per 1 ppm O₂ |
| Hydrazine | Volatile product | All | 1 ppm times 1 ppm O₂ |
| DEHA | Catalyzed, less toxic | All | 0.5-5 ppm |
| Carbohydrazide | Alternative to hydrazine | All | 1.5 ppm per 1 ppm O₂ |
Galvanic Corrosion
Caused by: Contact between dissimilar metals in the presence of electrolyte
Prevention
- Avoid dissimilar metal joints
- Use insulating gaskets
- Cathodic protection in condensate systems
- Strict control of pH and oxygen
Cathodic Protection
| Method | Application | Effectiveness |
|---|---|---|
| Sacrificial anodes | Small systems, tanks | Good |
| Impressed Current | Large Systems, Piping | Excellent |
Fatigue Corrosion
Caused by: Combination of cyclic stresses and corrosive environment
Critical Areas
- High stress points
- Welded joints
- Changes in section
- Areas of vibration
Prevention
- Proper design to minimize stresses
- Heat treatments for stress relief
- Strict control of water chemistry
- Inspections Periodic Ultrasonic Treatments
Steam and Condensate Treatment
Set up treatment to prevent corrosion in the condensate system.
Comparison Table: Condensate Return Water Quality
| Parameter | Quality Levels | Measurement Method | Recommended Frequency | ||
|---|---|---|---|---|---|
| ✅ Optimal | 🟡 Acceptable | ❌ Dangerous | |||
| pH (25°C) | 8.8-9.2 | 8.5-8.7 9.3-9.5 |
<8.5 >9.5 |
pH electrode (ISO 10523) | Continuous or daily |
| Iron (Fe) (ppb) | <10 | 10-20 | >20 | Spectrophotometry (ISO 6332) | Weekly |
| Copper (Cu) (ppb) | <5 | 5-10 | >10 | Spectrophotometry (ISO 8288) | Weekly |
| Dissolved Oxygen (ppb) | <5 | 5-7 | >7 | Amperometric electrode (ISO 5814) | Continuous |
| CO₂ (ppm) | <2 | 2-5 | >5 | Titration (ASTM D513) or sensor | Diary |
| Conductivity (μS/cm) | <50 | 50-100 | >100 | Conductivity meter | Continuous |
Treatment Options
| Problem | Treatment | Products | Dosage |
|---|---|---|---|
| CO₂ Corrosion | Neutralizing Amines | Morpholine, Cyclohexylamine, DEAE | 3-10 ppm (pH 8.5-9.2) |
| O₂ Corrosion | Corrosion Inhibitors | DEHA, Hydroquinone, MEKO | 0.5-5 ppm |
| Vapor Contamination | Carryover Control | Defoamers | 1-5 ppm |
| Contaminant return | Condensate filtration | Pre-coat filters, mixed beds | – |
Treatment Strategies
Volatile Treatment
- Hydrazine + Ammonia
- For high-purity systems
- Minimizes solids in the system
Amine Treatment
- Neutralizers (morpholine)
- Film (octadecylamine)
- Combinations
Physical Treatment
- Precoat Filters
- Exchange ionic
- Mechanical separators
Monitoring and Control according to ISO 5667 and EN 12952-12
Configure the monitoring parameters for the water treatment system according to:
ISO 5667-7: Sampling Guidelines
EN 12952-12: Water Quality Limits
EN 12952-12: Water Quality Limits
Sampling Protocols
| Spot | Sample Type (ISO 5667) | Frequency (EN 12952) | Preservation |
|---|---|---|---|
| Feed Water | Spot or Composite | Continuous/Hourly | Cooling, pH Adjustment |
| Boiler water | Spot-on | Immediate filtration | Each shift |
| Steam | Spot-on | Cooled condenser | Daily |
| Condensate | Spot-on | Hermetic containers | Each shift |
Water Quality Limits according to EN 12952-12
Note: Values for boilers Water tubes operating continuously
| Parameter | Feed Water | Boiler Water | |||
|---|---|---|---|---|---|
| ≤30 bar | >30 bar | ≤30 bar | 30-60 bar | >60 bar | |
| Conductivity (μS/cm) | ≤500 | ≤200 | ≤5000 | ≤3000 | ≤1000 |
| pH (25°C) | 8.5-9.5 | 8.5-9.5 | 10.0-11.0 | 9.5-10.5 | 9.0-10.0 |
| Dissolved Oxygen (μg/kg) | ≤20 | ≤10 | |||
| Total Iron (μg/kg) | ≤50 | ≤30 | – | – | – |
| Total Copper (μg/kg) | ≤10 | ≤5 | – | – | – |
| Silica (ppm SiO₂) | ≤500 | ≤200 | ≤15000 | ≤5000 | ≤2000 |
Key Regulatory References:
- EN 12952-12: Requirements for boiler and feedwater quality
- ISO 5667-7: Guide for boiler water and steam sampling
- EN 12953-10: Requirements for fire-tube boilers
Safety Considerations in Sampling (ISO 5667-1)
Precautions: Sampling boiler water may involve risks due to high temperature and pressure.
- Wear personal protective equipment (gloves, goggles, suitable clothing).
- Check that sampling valves are in good condition.
- Sample at points designed for this purpose
- Cool samples to high temperatures before handling
- Use containers appropriate for each type of analysis
Standards and References
Technical documentation and standards applicable to boiler water treatment.
Related ISO Standards
| Code | Title | Application |
|---|---|---|
| EN 12952-12 | Water-tube boilers – Requirements for boiler feedwater and boiler water quality | Water quality limits for boilers |
| ISO 5667-1 | Guide to the design of sampling programs | General design of sampling programs |
| ISO 5667-3 | Preservation and handling of water samples | Post-sampling handling |
| ISO 5667-7 | Guide to sampling Water and Steam Sampling in Boiler Plants | Boiler-Specific Sampling |
| ISO 5667-10 | Guide to Wastewater Sampling | Blowdown and Effluent Sampling |
| ISO 5667-14 | Guide to Quality Assurance Sampling | Quality Control |
Combined Key Requirements EN 12952-12 and ISO 5667
EN 12952-12 (Water Quality)
- Pressure Limits: Defines maximum values for each parameter by operating range
- Feedwater: Requirements for O₂, iron, copper, and silica
- Boiler water: pH, conductivity, and solids control
- Prevention: Anti-scaling and anti-corrosion criteria
ISO 5667-7 (Sampling)
- Representative points: Correct sampling location
- Frequencies: Daily minimum for critical parameters
- Preservation: Methods to prevent sample alteration
- Documentation: Record of conditions during sampling
Implementation Note: The limits apply according to EN 12952-12, while the verification methods follow ISO 5667-7.
Relationship between standards:
- EN 12952-12 establishes the limits for water quality.
- ISO 5667 defines the methods for verifying these limits.
ASME Boiler Water Standards
| Code | Title | Application |
|---|---|---|
| ASME BPVC | Boiler and Pressure Vessel Code | General requirements for boilers |
| ASME PTC 19.11 | Water and Steam in the Power Cycle | Water and vapor analysis |
| ASME Consensus | Industrial Boiler Water Limits | Limits recommended |
ASME Limits for Boiler Water
| Parameter | Feedwater | Boiler Water |
|---|
Other Technical References
EPRI (Electric Power Research Institute)
- Guidelines for water treatment in power plants
- Advanced Monitoring Protocols
- Corrosion Studies
ASTM Standards
- Standard Methods for Water Analysis
- Materials Testing Protocols
- Treatment Equipment Standards
APTA (Association of Water Technologies)
- Guides for Industrial Water Treatment
- Commercial Boiler Protocols
- Best Practice Manuals
Recommended References
- “The NALCO Water Handbook” – McGraw-Hill
- “Boiler Water Treatment Principles and Practice” – ChemTreat
- “Water Treatment Handbook” – Degremont
- “Combined Cycle Journal” – Artículos técnicos