Superior Boiler Watertube Boiler Operation & Maintenance Manual

Overview

Industrial watertube boiler system designed for continuous duty service. This manual covers initial startup, normal operation, maintenance, and emergency procedures.

Pre-Startup Safety Requirements

Before lighting any fire:

1. Ensure vertical safety valve discharge pipe is clear and won't touch during unit expansion
2. Verify gage glass and water level indicators are functioning
3. Ensure fuel burning equipment is in safe operating condition
4. PURGE setting of all combustible gas for 5 minutes minimum before ignition
5. If burner ignition is lost, completely purge before relighting
6. Install proper discharge pipes for blowoff and drain valves

Initial Startup Procedure

Water Preparation

1. Fill boiler with soft water (if available) to 2-3 inches below manhole using feedwater pump
2. Dissolve chemical treatment: 20 lbs Trisodium Phosphate + 2.5 lbs Caustic Soda per 8,000 lbs water
3. Pour chemical solution into boiler through manhole or chemical feed system
4. Close manhole and open drum vent
5. Raise water level to above normal using feedwater pump

Initial Firing Sequence

1. Completely purge setting with forced draft fan for 5 minutes minimum
2. Light burner at minimum firing rate
3. Leave drum vent open until steam blows at steady rate (approximately 5 psig)
4. Close vent and continue firing at minimum rate until 30 psi reached
5. Shut off burner for 15 minutes to equalize temperature
6. Relight and fire at minimum rate - approximately 1 hour to reach 75% line pressure or 100 psi (whichever is higher)
7. Shut off burner and refire as needed to maintain pressure for 4 hours
   • During 4-hour hold: crack open continuous blowdown line
   • Blow down water column every hour from 3/4 glass to 1/4 glass
   • Do not allow safety valves to pop (damage seats)
8. Fill to near top of gauge glass and maintain 75% line pressure
9. Blow down from full to 1/2 glass to reduce chemical concentration
10. Restore normal water level and raise pressure
11. Set safety valves at nameplate pressure
12. Place boiler online

Load Increase Protocol

1. Increase load gradually to not more than 1/2 load maximum
2. After 4 hours operation, blow down boiler to below recommended water treatment limits
3. If 1/2 load cannot be reached due to steam demand, extend 4-hour period to 12 hours
4. Inspect for oil presence on water surface - continue blowdown if oil detected

Normal Cold Startup (After Initial Startup)

1. Close boiler stop valve
2. Open drum vent and establish water level slightly below normal
3. Light burner at minimum firing rate (thermocouples determine safe rate for superheated units)
4. When steady steam flow from vent at ~5 psi, close vent valve
5. Continue firing until 30 psi reached
6. Shut burner off for 15 minutes
7. Relight and fire at minimum rate - 45 minutes to 1 hour to reach line pressure
8. Place water level regulator on automatic, start feed pump
9. After line pressure reached, open boiler stop valve
10. Bleed steam as load dictates, increase combustion air and fuel to maintain pressure

Water Treatment

Treatment Quality Importance

Proper water treatment prevents three major problems:

1. Internal Deposits: Causes furnace tube failures and overheating
2. Corrosion: Attacks boiler metal leading to leaks
3. Foaming: Causes carryover and steam quality issues

External Treatment (Recommended if makeup > 30%)

• Hot Lime Soda softeners - remove scale-forming calcium/magnesium
• Demineralizers - condition to virtually eliminate scale compounds
• Evaporators - provide makeup water free of suspended/dissolved solids

Internal Treatment

• Trisodium phosphate for hardness precipitation
• Caustic soda for pH control (alkalinity)
• Sodium sulfite for oxygen scavenging
• Chelating agents for residual hardness

Blowdown Requirements

• Continuous blowdown: Keep open during operation to maintain water quality
• Lower drum blowdown: Performed hourly during initial startup, as needed during operation
• Water column/gauge glass: Blow down for 2-3 seconds every 8 hours
• Recommended solids concentration: Keep below manufacturer-specified limits via blowdown

Normal Operation

Routine Monitoring

• Monitor water level in gauge glass (keep at center mark)
• Verify fuel pressure and combustion air flow
• Check steam pressure against gauge
• Listen for unusual noises (rumbling = scale/sludge, whistling = air in lines)
• Monitor feedwater temperature and flow

Pressure Control

• Fuel control modulates burner firing to maintain set pressure
• Automatic water level regulator maintains proper level
• Safety valves provide overpressure protection

Blowdown Schedule

• Every 8-12 hours: Blow down water column and gauge glass
• During startup: Every hour
• Daily: 5-10 minutes of continuous blowdown
• As needed: Increase if water clarity declines

Boiler Shutdown

Normal Shutdown

1. Reduce fuel input to minimum
2. Allow boiler to cool naturally
3. Close fuel supply valve
4. When pressure drops to zero, crack open drum vent
5. Close stop valve

Emergency Shutdown

1. Immediately shut off fuel supply
2. Open all blowdown and drain valves
3. Close fuel and air supply lines
4. Verify pressure gauge reads zero
5. Allow complete cooling before inspection

Inspection and Cleaning

External Inspection (Every 6 months)

• Check for scale buildup on tubes (sight glass)
• Inspect burner firing pattern
• Verify all gauges functioning
• Check for water leaks at connections
• Inspect refractory/insulation condition

Internal Inspection (Annually or as needed)

• Remove manhole cover when cool
• Inspect drum interior for deposits/corrosion
• Clean tubes if scale present using tube cleaner
• Inspect stays and baffle tubes
• Check for pitting or erosion

Chemical Cleaning (If heavy deposits)

1. Drain boiler completely
2. Prepare mild acid solution (20% HCl typical)
3. Circulate through boiler for 24-48 hours
4. Drain acid solution
5. Rinse thoroughly with soft water (multiple cycles)
6. Refill and perform normal startup procedure

Boiler Storage (Long-term layup)

Dry Storage Method (Preferred)

1. Drain boiler completely - use air pressure if needed
2. Dry interior with dry heat (portable heater in setting)
3. Place drying agent (calcium chloride/silica gel) in boiler
4. Close all openings with watertight caps
5. Inspect every 30 days and replace desiccant as needed

Wet Storage Method

1. Fill boiler with treated water
2. Add corrosion inhibitor (sodium nitrite: 1.5% solution)
3. Maintain slight pressure using inert gas (nitrogen)
4. Monitor water quality monthly
5. Drain and repeat every 6 months

Common Issues & Solutions

| Issue | Cause | Solution | |-------|-------|----------| | Low water level | Leaks, high usage | Check for leaks, adjust feedwater | | High pressure | Control malfunction | Check fuel control and pressure regulator | | Scale in tubes | Hard water/improper treatment | Perform chemical cleaning, improve treatment | | Foaming in drum | Water treatment issues | Blow down continuously, adjust chemicals | | Pilot won't light | Ignition failure, fuel supply | Check fuel pressure, verify ignition electrode | | Flame loss | Flame sensor issue | Clean sensor, verify air/fuel ratio | | Corrosion leaks | Acidic water/deposits | Improve water treatment, reduce oxygen | | Uneven heating | Sludge buildup | Perform internal cleaning |

Maintenance Schedule

Daily: Water level check, pressure verification, fuel observation Weekly: Continuous blowdown inspection, gauge function test Monthly: Water quality analysis, refractory condition check Quarterly: Safety valve setting verification, tube inspection Annually: Full internal inspection, chemical treatment review, efficiency test Every 2 Years: Major tube cleaning if needed, burner rebuild

Safety Features

• Safety valves: Set at nameplate pressure (prevent over-pressurization)
• Low water cutoff: Automatic burner shutdown if water level drops
• Flame failure: Automatic fuel shutoff if flame is lost
• Pressure gauge: Monitor for over-pressure condition
• Gage glass: Visual water level indicator with shutoff valves

Safety Warnings

• Steam hazard: High-temperature steam under pressure - risk of severe burns
• Chemical hazard: Caustic and phosphate chemicals can cause burns
• Explosion risk: Never plug safety valve or operate without blowdown
• Carbon monoxide: Ensure adequate ventilation - install CO detector
• Confined space: Internal inspection requires proper entry procedures
• Pressure relief: Safety valves must not be bypassed