.caustic embrittlement  .ce

Caustic Embrittlement ( Caustic Stress Corrosion Cracking) is the phenomena in which the material of a boiler becomes brittle due to the accumulation of CAUSTIC SODA (Sodium Hydroxide).

 Sodium Carbonate is used in softening of water to prevent scaling, due to this – some sodium carbonate maybe left behind in the water. As water evaporates in the boiler, the concentration of sodium carbonate is increases in the boiler. As the concentration of sodium carbonate increases, it undergoes hydrolysis to form Sodium Hydroxide at temperatures of 200 to 250°C.
Na2CO3 + H2O → 2NaOH + CO2
The presence of Sodium Hydroxide makes the water alkaline . This alkaline water enters to minute cracks present in the inner walls of the boiler by capillary action. Inside the cracks, the water evaporates and concentration of sodium hydroxide increases. This sodium hydroxide attacks the surrounding material and dissolves the iron of the boiler as SODIUM FERRATE (Na2Fe2O4) or Rust. This causes Caustic Embrittlement.

CAUSES:

There are many causes of caustic embrittlement, including the combined action of the following three components:
1. Usage of material like carbon steel
2. Alkaline chemicals such as concentrated NAOH
3. Tensile stress ( for example- around the riveted holes)

PREVENTION:

Caustic embrittlement can be prevented through several methods, including:
1. Controlling the temperature
2. Controlling the stress levels(Residual Or Load) and hardness
3. Use of materials that do not crack when used in given environments
4. Avoiding alkali where it necessary
5. Replacing Sodium Carbonates with Sodium Phosphate as softening reagents
6. Adding Lignin, Tannin or Sodium Sulphate that blocks hairline cracks as well as preventing infiltration of sodium hydroxide into the areas.

Note: Tannins and lignins are organic compounds found in plants and trees, particularly in bark, leaves, and seeds.  By volume, 25-30% of pine needles are composed of tannins and lignins, for instance. When these plants decompose in the environment, the hardy tannic and lignic enzymes are among the last to break down (due to bacterial resistance), and they give many water bodies and streams a naturally rusty color.

.boiler tube failure   .btf   .rbt

   Causes of boiler tube leakage:

• Erosion corrosion at tube inlet
• Excessive scale formation due to improper water treatment
• Overheating due to excessive soot buildup
• Flame impingement
• ‘Forcing’ of boilers
• Vibration due to slack bracing

Indications of excessive tube leakage

• Unable to maintain water level
• Unable to maintain steam pressure
• High feed water consumption
• Hotwell low level alarm
• Steam emission at funnel
• ‘Bursting’ noise
• Possibility of flame being extinguished if water gets into furnace
• When seen through furnace sight glass, furnace looks ‘misty’

Action

• Inform C/E
• If unable to maintain water level, stop firing and switch off burner control panel power supply
• Stop feed pump
• Change over to DO
• Close main steam stop valve
• Necessary to identify and plug leaking tube/s

Prevention

• Regular soot blowing and water washing
• Proper boiler water treatment
• Cold starting and firing procedure should be as per makers’ instruction

While it is recognized that plugging of 10%-15% of the total number of tubes within the tube nest generally reduces operational efficiency of the pressure plant, this level of plugging can be tolerated 

Stresses acting on boiler

• Thermal stress
• Longitudinal stress
• Circumferential stress or hoop stress

How do you differentiate between white smoke and steam smoke seeing in the funnel smoke?

• Answer: if it is white smoke, it will leave trail means it will travel some distance before disappear where the steam will not leave any trail it will disappear very quickly.

When and How would you carry out a hydrostatic pressure test on a boiler?

.boiler pressure test .bpt .blr pressure test

Hydrostatic pressure test is usually carried out when:

• When there is a major tube replacement
• When repairs/partial replacement is done to the boiler pressure part like partial repairs to the shell
• Surveyor may decide whether or not the pressure test should be done.

Procedure for test

• All welding must be done by graded welders acceptable to Class
• Ensure all mountings are in place and shut
• The safety valves’ mounting is blanked off
• The gauge glasses are removed or isolated by shutting the steam & water cocks
• The air vent valve is opened and water can be filled manually by the feed pump until water flows out from the air vent.
• Shut air vent valve
• Fix pressure pump and connection at the top usually at safety valve mounting
• Press up to 1.5 times the max. allowable working pressure
• Surveyor usually wants pressure to hold steady for at least 30 minutes and look for signs of leakage

Why can’t we use diesel engine exhaust gas for inert gas production?

Answer: As now a days most of the engines are super charged and in supercharged engine the amount of oxygen in exhaust gas is almost 17% but in inert gas system the oxygen content must be below 8% that is why main engine exhaust gas cannot be used.

Boiler Materials

• Shell – all-welded construction   – seamless steel
• Tubes – ERW seamless steel (Electric Resistance Welded (ERW)

.high water level   .boiler high water  .bhwl

• Sudden increase in steam demand and feed water flow increased but not reduced proportionately when demand is reduced
• Sudden drop in steam pressure and burners firing on full-load
• ‘Forcing’ of boilers can lead to ‘swelling’ and high level alarm, example:
• When starting boilers from cold. Keep water on lower limit of normal water level [as water expands on heating]
• Feed p/p running manually
• Faulty level transmitter.

Action for High Water Level Alarm

• Immediately slow down the steam operated machinery like cargo pumps, turbo-generators etc to prevent damage
• Change to manual and stop feed pump or manually throttle feed control valve
• Check local water level gauge to ascertain the high water level alarm. Blow through at least one gauge glass.
• Operate drain valve in steam line and bottom blow down until normal water level is established
• Check controller for sluggish operation and adjust P+I+D settings, ensure control air is clean [can happen after drydock after using shipyard supplied air]

Low Water Level Alarm

.boiler low water level   .blwl   .low water level

Likely causes:

• Check if feed pump is running and if suction and discharge pressures are almost the same, ‘vapour lock’ may be taking place
• Cascade tank low
• Check if auto level controller is working and in ‘open’ position
• Check if blow down valve is leaking or left open
•  look for signs of excessive boiler tube/s leakage

action for Low Water Level Alarm

• Stop firing and investigate
• Check local water level gauge to ascertain the low water level alarm. Blow through at least one gauge glass if possible.
• Change-over to another feed pump
• Open manual/direct filling valve

.bmd .boiler manhole door .manhole door .boiler door

Procedure for opening boiler manhole door:

1. Boiler depressurized
2. Boiler sufficiently cooled down
3. Drain the boiler water fully
4. Hold the top door with chain block before opening the manhole door nut. Open the top manhole door first to make sure the water is fully discharged
5. After opening top door, a sounding tape with water finding paste is inserted inside a tube to check whether the boiler is empty or not.
6. Then open bottom manhole door.

Why manhole door is elliptical

• any opening in a pressure vessel is kept to a minimum and for a man entry an elliptical hole is lesser in size than the corresponding circular hole.
• More over it is prime concern to have a smoothed generous radius at the corners to eliminate stress concentration. Hence other geometrical shapes like rectangle and square are ruled out. 
• To compensate for the loss of material in the shell due to opening, a compensating ring has to be provided around the opening.
• The thickness of the ring depends on the axis length along the direction in which the stresses are maximum and the thickness of the shell. It is important to align the minor axis along the length of the vessel, as the stress in this direction is maximum.
  →Longitudinal stress: Pd/2t where P= pressure inside the vessel, d= diameter of the arc, t= thickness of the shell plating 
  →Circumferential stress: Pd/4t 

Why manhole door is fitted inside

The manhole door of any pressure vessel is elliptical in shape and fitted from the inner side for safety reasons.
If there is any hidden pocket of pressure (that is not indicated in pressure gauge) because of its shape the door will not come out of the boiler/air bottle and thus preventing human injury.
To bring it out the door is inclined to some extent and bring it out.

What is the advantages of reflex plate gauge glass?

1. It is very thick and less chances of crack or break down
2. With this type of gauge glass water level can be seen from distance

 what is your course of action, if your boiler gauge glass is leaking ?

• Ans: There are 2 gauge glasses.
• If one gauge glass leaks, it is isolated and not used. The steam and water valves are shut and drain valve opened.
• At the first opportunity when the boiler is out of service and not under pressure, the leaking gauge glass is safely renewed.
• Trying to repair/replace leaking gauge under pressure by shutting the steam and water valves is not safe.

Answer: To keep the oil heated up as well as prevent heat loss from the steam.

Why in the condenser hot medium is outside and in the heater hot medium is inside?

• In the condenser hot medium is outside to assist heat radiation
• In the heater hot medium is kept inside to prevent heat loss

Why nox in the steam atomization burner is low while pressure atomization burner is high?

Answer:

• High oil pressure and high oil temperature in the pressure atomization burner produce high NOx
• But in steam atomization burner, high oil pressure and high oil temperature produce low NOx this is because of the steam which absorb some of the heat produced.

PA = Pressure Atomising         (KBO)

RC = Rotary Cup                      (KB, Aalborg make)

SA = Steam Atomising (KBSA, KBSD, Aalborg make)

How would you relate boiler combustion to MARPOL Annex VI regulations?

Answer:

• The NOx Technical Code applies only to diesel engines and does not apply to boiler combustion
• However, Regulation 14 applies. The sulphur content when in ECA area has to be limited to 0.1% and from 1^st January 2020, the global Sulphur limit is 0.5%
• Continuous emission of black smoke is prohibited

.rotary cup burner   .rcb

As the name suggests, this burner comprises a burner nozzle which is covered by a rapidly rotating cone. The fuel oil is carried on to a nozzle which is centrally located within the rotating cone. As the fuel oil moves along the cup due to absence of centripetal force, the oil film becomes thinner in its course as the circumference of the cup increases.
Ultimately, the fuel is discharged from the tip of the rotating cone in the form of fine atomized spray.

The spinning cup offers the following advantages:

>Wider turn down ratio with lower excess air

> Low 02 levels

> No requirement for atomising air or steam

> Low fuel pressure requirements to an extent that gravity flow is sufficient

> Stable flames achievable with very low fuel flows although maximum flow limited by size of cup. This, allied to being limited to side firing making the design more suitable for smaller installations.

Maintenance of rotary cup burner –

•  Clean the rotating cup
•  Check and adjust the belt tension between the motor and rotating shaft
•  Clean carbon deposited on the electrode ignite and adjusts the gap 
• Clean pilot burner nozzle and filter 
• Check the fuel valve and air register ( leakage in joints )
•  Check and clean the flame eye glass cover 
• Check and clean inspection peep hole glass cover 
• Adjust the fuel and air ratio, clean the fuel oil filter 
• Check the fuel oil pressure

Why rotary cup burner clearance is important?

Answer:

• If the clearance is high then the flame will move outward and become unstable
• If the clearance is low then the flame will move inward and causes burning to the cup tip.

Boiler turndown ratio defined

Boiler turndown is the ratio between a boiler’s maximum and minimum output. Depending on the burner’s design, it may have a turndown ratio between 5:1 and 10:1 or even higher. A 5:1 turndown means the boiler’s minimum operating load is 20% of the boiler’s full capacity (100% capacity divided by 5). A 10:1 turndown means the minimum operating load is 10% of the full load capacity (100% capacity divided by 10).

What is the function of tertiary air in the rotary cup burner?

Answer: flow of tertiary air can be controlled from outside

• it acts like a sealing air
• During combustion it blows away the product of combustion which helps to cool down the cup burner and reduce carbon formation.
• If the air flow is high, it hamper the initial combustion.

During overhaul,

1. The nozzle atomising holes should be inspected for signs of enlargement which can lead to improper fuel atomisation and bad combustion. Presence of cat fines in fuels will accelerate the wear of the nozzle holes.
2. The swirler plate should be inspected for erosion corrosion. The swirler plate converts pressure energy to velocity and increases the speed of the oil flow to give the required atomisation, turbulence & penetration
3. The ignition electrodes’ clearances are critical for flame establishment during start-up and should be set as manufacturers’ recommendation.

4. The ignition electrodes’ tips should not be worn, carbonised or pitted.

5. The ceramic isolator body in the ignition electrodes should not be cracked or broken to prevent current leakage

6. The air swirler vanes should not be dirty/carbonised

7. Photocell checked for cleanliness

8. Filters in pump and burner checked for cleanliness

.boiler survey  .boiler inspection

Boiler survey is Conducted every 2.5 years, twice in 5 years

Planning

1. Planning to be done and discuss with technical super.
2. Risk assessment to be done
3. Permit to work obtain
4. Check for necessary tools and spares
5. Check manual for special instruction and check past records
6. Next port steam consumption obtain
7. Personal involve to be briefed

Shutting down for survey

• Inform duty officer
• Change over M/E, A/E and boiler to DO
• Top up do service tank, stop all purifier.
• Stop tank heating and steam tracing
• Changeover boiler from auto to manual.
• Stop the boiler and purge for 3-5min
• Switch off power on panel and switch off circuit breaker for HFO pump and feed water pump
• Posted ‘do not start’ sign
• Shut main steam stop valve and shut fuel valve and feed water valve
• Let the boiler cool down
• When boiler pressure ~ 4 bar, carry out blow down
• When boiler pressure ~ 2 bar. Open vent
• Let the boiler cool down
• When sufficiently cooled at atmospheric pressure, open top manhole door with all safety precaution.
• Knock gently as may contain hot water/ steam
• When nothing coming out, open manhole with support of rope
• Open bottom hand hole door
• Ventilate for few hours.

Prepare for entry

1. Enclose space entry permit to be obtained
2. Wear proper PPE like safety shoes, helmet , hand gloves
3. Keep an inventory of tools taken inside
4. Keep one responsible engineer standby outside with clear emergency orders
5. Keep emergency breathing apparatus standby
6. Ensure proper lighting of ventilation
7. Carry a gas detector, manually calibrate it in open atmospheric condition
8. Ensure proper communication

Boiler inspection

I.  Foundation:

• Boiler supports, bolting and securing arrangements, (fixed and sliding seating, chocks, rolling stays if any) to be examined. (sbs)
• Look for sign of rust and wastage in the bolt and nuts.

II. Furnace: 

1. Check for distortion  
2. Distortion mainly due to:
   1. Overheating (excessive scaling, excessive thermal stresses etc.)
   1. Flame impingement (across the path of the flame)  
3. Check condition of refractory  
4. Check furnace bottom, should be free of oil deposits

III. Shell, tube plates and tubes:  

1. Weld cracks, in the way of valve openings  
2. Wastage in the way of manhole & hand hole flanges
3. Check Normal water region for cavitation, pitting etc.  
4. Inlet tube ends, for erosion/corrosion  
5. Checks for tube deformation, erosion, crack, wastage, s etc. 

IV. safety v/v: 

• safety v/v’s are to be overhauled and examined at each survey and opened as considered necessary by the surveyor  
• The proper operation of the safety v/v’s are to be confirmed at each survey  
• Boiler safety v/v’s easing gear is to be examined & tested satisfactory

 V.  All others boiler mountings: 

All boiler mountings to be overhauled for survey.

• Main steam stop valve  
• Air vent valve  
• Sampling v/v  
• Scum blow down v/v  
• Feed stop & check v/v  
• Water level gauge glass 
• Pressure gauge to be calibrated 
• Manhole covers  
• Soot blowers
• Blow down v/v  

VI. Hydraulic test:

1. To be carried out if an alteration/repairs have been carried out on highly stressed parts.
2. Major tube renewal has been done 
3. Shell plating renewal 
4. Usually, 1 .5 times the max Working Pressure 
5. Can be requested at the discretion [1] of the surveyor

VII. External inspection: 

Upon completion of the internal survey, the boiler is to be examined under steam, with the fuel oil burners and safety devices and all other mountings under working condition.

following alarm test to be done.

1. Water level high high – Automatic shutdown with alarm (requirement if ship fitted with steam operated machinery)
2. Water level high- Alarm
3. Water level low-ALARM 
4. Water level low-low – Automatic shutdown with alarm
5.  FD fan or flame failure- Automatic shutdown with alarm

VIII. Logbook

Review of boiler operation & feed water test records.

IX. Manual emergency shutdown:

• Boiler’s forced-draft fan & fuel oil service pumps are to be fitted with remote means of control situated outside the space in which they are located so that they can be stopped in the event of fire.
• Testing of local emergency stop function

[1] the quality of behaving or speaking in such a way as to avoid causing offense or revealing private information.”she knew she could rely on his discretion”

• Boiler’s forced-draft fan & fuel oil service pumps are to be fitted with remote means of control situated outside the space in which they are located so that they can be stopped in the event of fire.
• Testing of local emergency stop function

Boiler Flash up procedure

.boiler flush up  .boiler cold start

1. internal surface to be clean and no tools and rags left inside
2. All openings of mountings cleaned properly
3. Mountings to be fixed back with new gaskets
4. Manhole, hand hole , furnace are closed
5. Ensure vent, alarms and pressure gauge connection valves are open
6. Ensure all drain valves are shut
7. Switch on power on boiler panel and put all circuit breaker to normal
8. Open fuel valve and feed water valve and start pump
9. Ensure all system running ok
10. Start filling boiler with water just below normal level as level will swell up when boiler fired
11. Fire the boiler at lowest possible rate
12. Continue fire intermittently. 1min fire- 10 min stop. After 1^st hour, 2min fire10 minute stop
13. When steam comes out vent, shut vent
14. Carry out gauge glass blow down
15. Check boiler for abnormalities
16. Adjust safety valve pressure setting
17. Slowly crack open main steam stop valve and open full
18. With boiler running, check all safety alarm.

.safety valve inspection  .bsvi .safety valve survey .bsvs

Valve & Seat

• Check visually for any sign of scoring (scratches), pitting etc
• Carry out a ‘mating check’ between valve and seat using Prussian blue or engineers’ blue
• A continuous ring indicates there will be no leak between valve and seat

 Spindle

• The spindle is always under compression during service. As such, it is prone to get bent.
• Checks must be done to ensure its ‘straightness’ or ‘true-ness’

 Spring

• Visual inspection carried out for excessive pitting due to rusting. The common spring material is carbon steel which gives the right stiffness but is prone to rusting. (FYI, stainless steel has very high stiffness)
• Due to ‘skewering effect’, springs tend to slant to one side over time. Check for perpendicularness.
• Due to prolonged compression, spring tends get ‘shortened’ .Free length (after usage) > 95% of natural length (when new)

 Valve Body

• Look for signs of corrosion inside/outside of valve body
• Check for scale deposits build-up inside body

Drain Pipe

– Ensure drainpipe is clear by blowing with air

What should be the capacity of each safety valve? (For guidance)

Answer: Each safety valve should match the maximum steam generation rate of the boiler

Why do you set the second safety valve slightly higher than the first valve?

Answer: If the first safety valve fails to lift, then the second safety can act as a back-up.

Then why can’t you set both the safety valves equally?

Answer: If both the safety valves lift together, then the blowdown will double which is not economical due to excessive loss of steam pressure.

What is the difference between Design Pressure (DP) and Maximum Allowable Working Pressure (MAWP)?

Answer: In most cases, they are of the same value.

However, during newbuilding, if you have sourced for a boiler with DP 12 bars but ship’s heating coils designed to withstand 10 bars, then the ship’s boiler can only operate to a maximum of 10 bars which is the MAWP.

DP is no longer valid on the ship.

Your boiler has a design pressure of 10.0 bars. You would like to operate your boiler at maximum working pressure.

• What can be the settings of your safety valves?

Answer: Maximum settings of safety valves are about 9.7 bars & 10.0 bars maximum.

The Maximum Working Pressure is usually 10% lower than the safety valve setting. MWP is 9.0 bars.

State the operational problems encountered in service for the boiler safety valves.

• Due to wear between valve and seat, lip clearance reduces and causes increase in blowdown
• Drain passage getting choked causing water accumulation and hence prevent smooth valve operation
• Spring tends to rust and cause valve seizure
• Valve spindle bending due to constant compression (can cause valve to have erratic/sluggish operation)

What is the purpose of lip clearance?

Answer: The purpose of lip clearance is made for valve lid to sit completely on seat or if clearance is zero then the valve lid cannot seal or close completely. It is measured by lead ball kept between lip and assemble the valve properly.

During inspection, if you find the valve and/or seat is badly scored, how would you rectify the defect?

In case the mating surfaces between the valve and seat are badly scored, they can be rectified by grinding.

Valve: Can be grinded against a cast iron plate, using a fine grained carborundum paste stirred in kerosene.

Seat: The seat in the valve body can be grinded in the same way by using a cast iron rod of suitable size. Use ‘Prussian Blue’ to do the mating surface check

Never use the valve itself when grinding the seat. This will increase the wear of valve and seat.

What are the routine checks carried out to ensure the proper operation of the safety valves?

• Check for any water/steam seepage from drainpipe fitted to safety valve. Drainpipe must be dry
• Check escape pipe if it is hot due to steam leakage (use infra-red thermometer)
• Check at funnel for any sign of steam emission
• If there is a slight leakage, manually operate the easing gear

You are the Senior Engineer onboard a tanker. You receive instruction from charterers to maintain your steam pressure at maximum 8.0 bars to prevent overheating of cargo. What is your action?

• In oil-fired boilers, I would set the automatic burner to cut-out at 8.0 bars.
• In waste heat recovery systems, I would set the ‘steam dump’ controller at 8.0 bars
• Above actions will maintain the steam pressure at a maximum of 8.0 bars

How to check the previous setting of the safety v/v

Answer: by checking the compression ring.

how to check the spring is perpendicular?

answer: by engineer square or the L scale.

How do you check the straightness of a spindle?

Answer: mount in the lathe machine and slide the dial gauge axially with the spindle.

.boiler

 Safety Valve Sketch, setting and Testing. Label all parts and materials

Safety v/v Setting

.bsvs    .boiler safety valve setting  

1. Safety valve to be overhauled and reset at every survey
2. At least 2 calibrated pressure gauge required
3. Loosen lock nut, screw down the compression screw few more turns then previous setting. Measure the height make marking
4. With all mounting in place, shut the main steam stop valve.
5. Fire the boiler on auto
6. Once boiler auto cut off, switch to manual. Rise the boiler manually till require set pressure
7. At this setting, unscrew the compression till safety valve lift
8. Fire the boiler continuously and check the safety valve lift at set pressure
9. Stop the boiler and check safety valve sit firmly at seating and no leakage
10. Safety valve now has been adjusted, tighten lock nut. This valve then had to be gagged
11. Set the other safety valve in same procedure
12. But this valve is usually set about 3% higher than the earlier valve
13.  Remove the gagging tool.
14. Lift the safety valve with easing gear and confirm it sit firmly and no leakage.

boiler safety valve SOLAS requirement

.bsvr   .boiler safety valve  .svr  .boiler safety valve regulation

• Each boiler (including exhaust gas boiler) is to be fitted with at least one safety valve and where the water-heating surface area is more than 46.5 m2, two or more safety valves are to be provided.
• Quick Estimation of heating surface area    = Π x D x L x N  (circumferential area of tubes)

   ≠ Π/4 x D² x L x N (this is for flow calculation)

D = dia. of tube, L = length of tube,

N = total number of tubes

1.  Valve Size
   • The safety valve bore must be between 19 to 100 mm
   • (Some class/countries use the imperial system   of  ¾^” to 4^” example ABS)

2. Accumulation Pressure Test

• With the steam stop valve shut and the boiler burner firing continuously at full-load capacity, the maximum pressure built up in the boiler should not exceed 6% above the maximum allowable working pressure
• It is also conducted during the commissioning test.

Purpose: To ensure the safety valve relieving capacity matches the rated steam generation rate.

3. Safety Valves relieving capacity

• The aggregate relieving capacity of the safety valves must not be less than the evaporating capacity of the boiler under maximum operating conditions.

Purpose: Biggest safety valve is 100 mm bore.

100 mm bore   =    50,000 kg/hr

If your maximum evaporation rate is 100,000 kg/hr, then you need 2 pairs of safety valves. ULCC/VLCC tankers have been known to have 2 pairs of safety valves

4. Easing Gear

• Each safety valve is to be fitted with an easing gear by which the safety valves can be operated from a safe platform either by hand or by mechanical means.

Purpose: – To carry out routine functional/ operational test of the safety valve

               – To release excessive steam pressure in an emergency.

• Escape Pipe (Outlet of safety v/v)
• The area of the escape pipe must be equal or greater than the outlet area of each safety valve
• The pipe should be free of any restriction

  Purpose:

• To prevent build-up of steam pressure in the escape pipe
• No valves to be fitted so that if the valve is shut, then safety valve becomes useless

Blowdown of safety valve:

Link: https://shipsengine.com/blowdown-meaning-of-a-boiler-safety-valve/

• Blowdown   = Opening Pressure – Closing Pressure
• Too Little Blowdown
• Rapid opening and closing of the valve can cause the valve and seat to get damage Also called the ‘chattering effect’
• Too Much Blowdown
• Unnecessary loss of steam pressure
• Not economical as heat energy, water, boiler chemicals etc lost

.sulzer fuel p/p timing  .sfpt     .sulzer timing 

procedure of checking the timing for valve control type fuel pump

Initial preparation and safety checks

Ø Tool box meeting carried out.
Ø Arrange appropriate tools and instruction manual to keep ready
Ø Take permission to immobilize the engine
Ø After permission granted carry out proper shutting down procedure of M/E
Ø Starting air system and starting mechanism to be isolated
Ø Open indicator cocks and engage turning gear
Ø Propeller clearance taken
Ø Shut off fuel oil supply
Ø Any setting to be done refer to instruction manual
Ø VIT hand setting lever is set to zero. Fuel lever is set to maximum with engine set run ahead
Ø Pump is isolated and drained
Ø Remove cover, spring and delivery valve above the plunger
Ø Remove the cover and spring above the suction and spill valve

Procedure for checking timing of pump

Step1

· Turn the engine in ahead direction until pump plunger is at top dead centre
· Fit dial gauge to the suction valve
· After tensioning the gauge set it to zero

Step 2:

• Turn the engine in astern direction until pump roller is on cam base
• Fit dial gauge to the plunger and spill valve
• After preloading the gauge set them to zero.

Step 3
· Turn the engine in ahead direction until the suction valve gauge reads 0.02 mm
· At this point suction valve is just closing  and fuel delivery to begin
· Note the plunger dial gauge reading (a) and crank angle

Step 4
· Continue to turn the engine in ahead direction until the spill valve gauge reeds 0.02 mm
· This indicates that the spill valve is just opening and fuel delivery will stop
· Note the plunger dial gauge reading (b) and crank angle
· Effective plunger stroke= b-a
· Maximum admissible deviation is 0.2 mm
· Check all values with setting table.    

c. Safety checks after adjustment

The following point to be checked

1. The zero position in the load indicator and setting shield on the fuel pump must be coincide.
2. When the pump is manually cut out there must be some clearance exists between the roller and the cam peak( 0.5mm minimum)
3. Safety cut out checks of the pump should be done after every resetting and after every major overhaul.
4. When the safety cut device is activated the suction and spill valve should lift from the seat thus ceasing the fuel injection.               
5.  This is important to ascertain that engine can be shut down / stopped positively at any time due to emergency and engine does not get overloaded.
6. When the shield position is zero then suction and spill valve will never be closed at same time in an individual pump.ie when one valve is closed other valve must be open so that the fuel injection excluded this determines the effective delivery stroke is zero.

Man B&W draw and explain

1. The pump is basically a jerk type with a plunger moving in a matched barrel
2. Helical grooves machined in the plunger to control the end of injection by uncovering spill ports and causing the discharge pressure to drop rapidly, thus causing the needle valve in the injector to close.
3. Oil is supplied to the barrel via the spill ports and a suction valve.
4. The suction valve, situated at the top of the barrel opens during downward stroke of plunger, while spill ports are covered by plunger.
5. Replaceable erosion plugs are fitted in the pump housing opposite the spill ports.
6. The high pressure oil, spilling back, as the edge of the helix uncovers the spill ports at the end of injection, hit the plugs, which prevent damage to the pump casing
7. A puncture valve is fitted in the top cover of the pump. It is opened when compressed air from the control air system acts on top of a piston fitted in the top cover. Fuel oil from the discharge side is then returned to the suction side of the pump and no injection takes place.

How to check timing

.fuel pump timing .fp timing .fo pp .fo pump   .fpt

Optical method

1. Set fuel rack to maximum
2. Open spills plug of pump and clean thoroughly
3. Turn engine 20 degree before TDC
4. Ensure no oil, put light on suction
5. Wear goggle, look through spill port
6. Turn until TDC
7. When light disappear, indicate start of injection
8. Check the crank angle marked on fly wheel. This value is the injection timing of that pump.

Oil overflow method

1. Stop fuel pump,
2. Fuel rack to max
3. Take out delivery pipe, puncture suction valve,
4. Turn to BDC, put DO, oil will flow out,
5. Turn towards TDC, flow will stop, record start of injection
6. Continue until overflow again, indicate end of injection

Checking of fuel pump lead,

.fuel pump lead   .pump lead   .fpl 

Pump lead-number of mm , top of plunger lifted above the upper edge of spill ports when piston is at TDC

Cam lead -number of mm plunger is lifted from bottom position when piston at TDC

Planning and preparation

1. Inform master about the  job and instruct to person get ready and arrange tools.
2. Go through instruction Manual
3. Check measuring tools
4. Risk assessment carried out, prepare work permit
5. obtain Immobilization
6. Stop engine. Shut starting air valve and drain the system
7. Open indicating cocks, get propeller clearance and engage T/G
8. Turn engine with lubrication on for 20 minutes
9. Stop LO pump, FO supply pump and FO circuiting pump
10. Shut FO inlet and outlet vlv.
11. Shut FO heater valve,
12. Drain off fuel carefully
13. Ensure personal safety
14. Disconnect puncture valve
15. Disconnect suction valve

Procedure

• Set FO rack max, VIT rack “zero”
• Put Reverse mechanism in ahead position
• Take out erosion plug both side
• Set the measuring tool
• Turn the engine in ahead direction until plunger cover spill port, take measurement “K”
• Compare reading with maker data
• If not correct, may be tool not seated properly. Clean top of plunger and set again
• When K match, turn unit to TDC and note value. This is “A” value, pump lead!
• Turn the engine in ahead direction until fuel pump roller is at lowest part of cam
• Push down the gauge, take reading. This is “b” value ! A-b= C, is the cam lead!
• Then Confirm pump lead and cam lead with maker data

Cutting off the fuel for B&W

The steps are:

1. Operating the Puncture Valve
2. Lift the Fuel Pump Roller.
3. Shut Fuel Oil Inlet Valve (Only for Maintenance purpose – Not During Running).

Manual actuation of Fuel Pump Lifting Device (148) activates Cylinder 149, which lifts & locks the Fuel Pump Roller, so that there is a gap (approx. 2 mm) between the roller and cam.

Cutting of fuel for Sulzer

• Lift fuel pump plunger by manual handle, !
• Close the inlet and outlet fuel valve.

.emergency generator not starting .not starting

Emergency generators are a critical backup power source on ships, designed to automatically start and connect to the emergency switchboard within 45 seconds of detecting a main power failure. However, there are several potential reasons why an emergency generator may fail to connect properly during an actual blackout situation:

Common Causes of Connection Failures

1. Battery Issues
2. Weak or dead starting batteries can prevent the emergency generator from starting.
3. Regular testing and maintenance of batteries is crucial.

2. Fuel System Problems
3. Contaminated fuel, clogged filters, or air in the fuel lines can prevent proper operation.
4. Fuel quality and fuel system integrity must be regularly checked.

3. Automatic Transfer Switch Malfunction

3. The switch that transfers load to the emergency generator may fail.
4. Regular testing of the transfer switch is important.

4. Governor/Speed Control Issues

4. Improper speed regulation can prevent the generator from reaching proper voltage/frequency.
5. Governor maintenance and calibration is essential.

5. Voltage Regulator Problems

5. A faulty voltage regulator may prevent proper voltage output.
6. Regular testing of voltage regulation is needed.

6. Breaker/Relay Failures

6. Faulty breakers or relays in the emergency switchboard can prevent connection.
7. Switchboard components require periodic inspection and testing.

7. Sensor/Control System Faults

7. Malfunctioning sensors or control logic may fail to detect the blackout condition.
8. Control system integrity must be verified regularly.

8. Air Intake Issues

8. Blocked air intakes or failed intake louvers can starve the engine of air.
9. Air intake systems require inspection and testing.

9. Cooling System Problems

9. Coolant leaks or failed pumps can cause overheating and shutdown.
10. Cooling system maintenance is critical.

10. Mechanical Failures

10. Internal engine damage or seized components can prevent operation.
11. Regular inspections and maintenance are necessary.

Preventative Measures

To minimize the risk of emergency generator connection failures:

• Conduct weekly no-load test runs
• Perform monthly load tests
• Regularly test automatic start and transfer systems
• Maintain fuel, lubrication, and cooling systems meticulously
• Inspect and test all control components periodically
• Follow manufacturer’s maintenance schedules rigorously
• Train crew on manual emergency procedures

Troubleshooting Steps

If the emergency generator fails to connect during an actual blackout:

1. Attempt manual start from emergency generator local panel
2. Check for alarms/faults on generator control panel
3. Verify fuel supply and system integrity
4. Check battery voltage and connections
5. Inspect air intake and exhaust systems
6. Examine switchboard for tripped breakers or blown fuses
7. Test voltage regulator and governor operation
8. Inspect for any visible mechanical damage

Regulatory Requirements

SOLAS regulations require:

• Emergency generators must start and connect automatically within 45 seconds of power loss
• Vessels must have at least two independent means of starting the emergency generator
• Weekly testing and monthly load testing of emergency generators
• Detailed records of all tests and maintenance to be kept

Conclusion

While emergency generators are designed for high reliability, they remain complex systems with many potential points of failure. Rigorous testing, maintenance, and crew training are essential to ensure these critical backup systems will function when needed most. Understanding common failure modes and proper troubleshooting procedures is crucial for all marine engineers responsible for shipboard power systems.

In a high-traffic area like Singapore, a blackout on a ship is a critical situation that demands immediate and precise actions to ensure safety. Here are the detailed steps to take:

1. Raise Alarm and Notify Authorities:

   – Immediately sound the general alarm to alert all crew members.

   – Inform the Vessel Traffic Services (VTS) in Singapore and other nearby vessels about the blackout situation. This can be done using VHF radio on the distress and safety frequency (Channel 16).

2. Assess the Situation:

   – Quickly evaluate the extent of the blackout. Determine whether it affects the entire ship or specific systems.

   – Check for any immediate hazards or dangers to the ship, crew, and nearby vessels.

3. Activate Emergency Procedures:

   – Implement the ship’s emergency blackout procedures as outlined in the Safety Management System (SMS).

   – Switch to emergency power if available. Start emergency generator.

4. Maintain Navigational Safety:

   – Ensure the ship’s emergency lighting, navigation lights, and sound signals are operational.

   – Use manual steering if the automated systems are down and the rudder can be controlled manually.

5. Reduce Speed or Stop the Ship:

   – If possible, reduce the ship’s speed to minimize the risk of collision. If the engines are not operational, drop the anchor to prevent drifting.

6. Display Appropriate Signals:

   – Exhibit the Not Under Command (NUC) shapes (two black balls in a vertical line during the day) or lights (two all-round red lights in a vertical line at night).

7. Communicate with Nearby Vessels:

   – Continuously update nearby vessels about your status and intentions using VHF radio.

   – Request assistance from nearby vessels, if necessary, especially for towing or escorting through the high-traffic area.

8. Restore Power:

   – Engineers and technical crew should work to identify and rectify the cause of the blackout. This could involve:

     – Checking the main switchboard for faults.

     – Inspecting and restarting the main and auxiliary engines.

     – Examining fuel systems for blockages or issues.

9. Keep Bridge Staff Informed:

   – Maintain a clear line of communication between the bridge and the engine room.

   – Ensure the bridge team is updated on efforts to restore power and any changes in the ship’s status.

10. Prepare for External Assistance:

    – Be ready to accept external assistance, such as tugboats, if offered or required.

    – Prepare mooring lines and other equipment necessary for being towed or assisted.

11. Review and Learn:

    – After the situation is under control, conduct a thorough review to understand the cause of the blackout.

    – Implement corrective actions to prevent future occurrences.

Handling a blackout in a high-traffic area requires coordination, clear communication, and swift action to ensure the safety of the ship, its crew, and other vessels in the vicinity.

.blackout .high traffic .blackout in heavy traffic .blackout in high traffic

Answer:

1. Raise the alarm and notify authorities

2. Assess the situation quickly

3. Activate emergency procedures

4. Maintain navigational safety.

5. Reduce speed or stop the vessel if necessary

6. Display appropriate signals

7. Communicate with nearby vessels

8. Restore power as soon as possible

9. Alert the bridge and keep them informed

10. Prepare for external assistance if needed

Additionally:

11. Start the emergency generator

12. Identify the cause of the blackout

13. Inspect critical systems

14. Inform relevant personnel

15. Communicate status updates externally

16. Monitor systems as power is restored

17. Debrief and report on the incident

18. Implement preventive measures

19. Ensure crew safety and maintain situational awareness throughout

This plan combines immediate safety actions with steps to restore power and manage the incident effectively in a high-risk environment. The focus is on safety, communication, and swift restoration of critical systems.

—

*To: Third Engineer (3/E)* 

*From: Chief Engineer (C/E)* 

*Subject: Generator Major Overhaul Instructions*

*Date: [Insert Date]*

—

*Objective:*

To perform a comprehensive major overhaul of the ship’s generator to ensure optimal performance and reliability.

—

*Instructions:*

1. *Preparation:*

   – *Safety First:* Ensure all necessary personal protective equipment (PPE) is worn, including gloves, safety glasses, and hearing protection.

   – *Isolation:* Isolate the generator from the electrical system. Lock out and tag out (LOTO) procedures must be followed strictly.

   – *Work Area:* Clear the work area of any unnecessary items and ensure adequate lighting and ventilation.

2. *Documentation:*

   – *Manuals:* Refer to the generator’s operation and maintenance manual for specific guidelines and tolerances.

   – *Checklists:* Use the provided maintenance checklists to ensure no step is missed.

   – *Record Keeping:* Document all findings, measurements, and parts replaced in the maintenance log.

3. *Inspection:*

   – *Visual Check:* Inspect the generator for any visible signs of wear, damage, or oil leaks.

   – *Connections:* Check all electrical and mechanical connections for tightness and integrity.

   – *Alignment:* Verify the alignment of the generator and prime mover (e.g., engine or turbine).

4. *Disassembly:*

   – *Components:* Carefully disassemble the generator, taking note of the order and orientation of parts.

   – *Cleanliness:* Keep all removed parts clean and organized. Use clean containers to store small components.

   – *Rotor and Stator:* Pay special attention when handling the rotor and stator to avoid damage.

   – *Mechanical Parts:* Disassemble mechanical components such as pistons, cylinders, connecting rods, and crankshaft if applicable.

5. *Inspection of Components:*

   – *Bearings:* Inspect bearings for wear or damage. Replace if necessary.

   – *Windings:* Check the windings for insulation resistance and signs of overheating or damage.

   – *Slip Rings/Commutator:* Examine the slip rings or commutator for wear, scoring, or pitting. Clean or replace as required.

   – *Cooling System:* Inspect the cooling system components, including fans, heat exchangers, and ducts.

   – *Mechanical Parts:*

     – *Pistons and Cylinders:* Check pistons and cylinders for wear, scoring, or pitting. Measure clearances and replace if out of tolerance.

     – *Connecting Rods:* Inspect connecting rods for cracks or wear. Check the alignment and replace if necessary.

     – *Crankshaft:* Examine the crankshaft for wear, cracks, or misalignment. Measure journal diameters and check for any signs of damage.

6. *Cleaning:*

   – *Degreasing:* Clean all parts using appropriate solvents and degreasers.

   – *Drying:* Ensure all parts are thoroughly dried before reassembly.

   – *Ventilation Paths:* Clean all ventilation paths and cooling fins to ensure efficient heat dissipation.

7. *Reassembly:*

   – *Lubrication:* Apply the recommended lubricants to bearings and other moving parts.

   – *Torque Specifications:* Use a torque wrench to tighten bolts and nuts to the specified torque values.

   – *Alignment:* Recheck the alignment of the generator and prime mover during reassembly.

   – *Mechanical Parts:*

     – *Pistons and Cylinders:* Carefully reassemble pistons and cylinders, ensuring correct orientation and clearance.

     – *Connecting Rods:* Reassemble connecting rods with the correct torque settings and alignment.

     – *Crankshaft:* Reinstall the crankshaft, ensuring proper alignment and lubrication.

8. *Testing:*

   – *Pre-Startup Check:* Perform a pre-startup check to ensure all connections are secure and all components are correctly installed.

   – *Startup:* Start the generator and monitor it closely for any abnormal noises, vibrations, or readings.

   – *Load Test:* Perform a load test to ensure the generator operates correctly under load conditions.

9. *Post-Overhaul:*

   – *Final Inspection:* Conduct a final inspection to verify the generator is operating within the specified parameters.

   – *Documentation:* Update the maintenance records with all work performed, including parts replaced and test results.

   – *Report:* Prepare a detailed report on the overhaul process, highlighting any issues encountered and solutions implemented.

—

*Notes:*

– If at any stage you encounter issues beyond your expertise, do not hesitate to consult with senior engineers or the manufacturer’s technical support.

– Ensure all replaced parts are documented and properly disposed of according to environmental regulations.

—

*Chief Engineer Signature:*

*Date:*

—

Please proceed with the overhaul, following the instructions diligently. Ensure all safety protocols are adhered to, and maintain a high standard of workmanship.

—

If you need any further assistance, feel free to reach out.

Best regards, 

[Chief Engineer Name]

—

.De-tuners .detuner .detuner   .dt

The natural frequency of vibration is always present in engines, but the effect can be dangerous when the vibration frequency reaches high levels.

This happens when the natural frequency of vibration from an external source integrates with the engine vibration or when there are out-of-balance forces generated inside the engine 

This can result in severe damage to the marine engine’s internal moving parts, cracks in the structure, loosening of bolts and securing and damage to bearings. Vibration of Marine Engines is mainly due to- Axial and Torsional Vibration or combination of both.

In order to reduce such vibrations, different methods and systems are used, which includes de-tuners, dampers thrust pads, chokes

De-tuners are used to alter the frequency of the vibration of the engine thus reduce the vibration of the engine.

Frictional type Bracing is one such de tuner Normally fitted on the top of the engine which increases the stiffness and raises the natural frequency beyond the working range. 

Friction type bracing is one of the common types used for 2 stroke slow speed marine engines.

The working of these type of bracing depends upon the friction between the pads that brace the engine at the top so that the resonances occurs above the speed range of the engine.

Last but not the least, the tension on the bolts must be regularly checked along with the inspection of the structure for any cracking especially around the welds.

Axial Damper: The Axial damper is fitted on the crankshaft of the engine to dampen the axial vibration which is generated by the shaft in forward and aft directions, parallel to the shaft horizontal line.

It consists of a damping flange integrated to the crankshaft and placed near the last main bearing girder, inside a cylindrical casing. The casing is filled with system oil on both side of flanges . This oil provides the damping effect.

When the crankshaft vibrates axially, the oil in the sides of the flange circulates to the other side through a throttling valve, which gives a damping effect.

high temperature alarm and pressure monitoring alarms located on both sides of damping flanges. They give alarm if one side oil pressure drops more than the set value as a result of low LO supply or sealing ring failure.

Torsional Damper:  twisting phenomenon in the crankshaft spreads from one end to the other due to uneven torque pulses coming from different units of the engine

The most famous type of torsional damper used on ship is Viscous type dampers, which consist of an inertia ring

This ring is added to the crankshaft and enclosed in a thin layer of highly viscous fluid like silicon. The inertia ring is free to rotate and applies a lagging torque on the crankshaft due to its lagging torsional motion.

When the crankshaft rotates, the inertia ring tends to move in radial direction but the counter effect is provided by the silicon fluid which damp the vibration.

.squat effect

The Squat Effect: A Hydrodynamic Phenomenon in Shallow Waters

The squat effect is a hydrodynamic phenomenon that occurs when vessels navigate through shallow waters, causing them to sit lower in the water than expected. This effect is primarily caused by the acceleration of water flow between the ship’s hull and the seabed in confined areas, resulting in reduced pressure and increased draft.

Causes and Characteristics

Water Flow Dynamics:

As a ship moves through shallow water, the confined space between the hull and seabed causes water to accelerate, leading to a pressure reduction.

Vessel Design Impact:

The Block coefficient (Cb) of a vessel influences its squat behavior:

• Vessels with Cb < 0.7 tend to squat by the stern (Cb < 0.7 is finer ship designed for speed)
• Vessels with Cb > 0.7 typically squat by the head or bow (Cb > 0.7 is heavier ship designed for more cargo carrying capacity)

Speed Relationship:

The squat effect is approximately proportional to the square of the ship’s speed. Reducing speed by half decreases the squat effect by a factor of four.

Conditions Affecting Squat

• Most noticeable when the depth/draft ratio is less than four.
• More pronounced when sailing close to a bank
• Can lead to unexpected groundings and handling difficulties

Indicators of Squat

Mariners and ship pilots should be aware of the following signs:

1. Vibration
2. Poor helm response
3. Shearing off course
4. Change of trim
5. Change in wash ( vessel wash: trailing effect of water churning left by propeller rotation)

Prevention and Management

To minimize the squat effect and ensure safe navigation, the following measures can be taken:

1. Speed Control: Maintain slow speeds in shallow waters.
2. Avoid Shallow Waters: When possible, steer clear of shallow areas and narrow channels
3. Maintain Safe Distances: Keep a safe distance from banks and other structures
4. Draft Management: Ensure the ship’s draft is appropriate for the water depth
5. Continuous Monitoring: Closely monitor the ship’s speed and draft

.Maneuverability .maneu .manoeu
Maintaining Vessel Maneuverability as a Chief Engineer

As a Chief Engineer onboard a ship, maintaining vessel maneuverability is crucial for safe and efficient operations. Here are key practices to ensure optimal maneuverability:

Regular Maintenance

Conduct routine inspections and maintenance on critical systems:

• Propulsion system: Regularly service the main engine, gearbox, and propeller
• Steering gear: Perform periodic checks on the rudder system, including mechanisms like the tiller and pintles
• Bow thrusters: If equipped, maintain in good working condition

Hull and Propeller Care

• Keep the hull clean and free of marine growth to reduce drag and improve maneuverability
• Regularly inspect and maintain propellers, addressing any damage or inefficiencies promptly

Lubrication and Fuel Quality

• Ensure proper lubrication of all moving parts in the propulsion and steering systems
• Monitor and maintain optimal fuel quality to prevent engine performance issues

Electrical and Control Systems

• Maintain electrical systems and connections to ensure reliable power for maneuvering equipment
• Keep navigation and control systems updated and properly calibrated

Stability and Trim

• Monitor and adjust ballast as needed to maintain proper stability and trim
• Regularly check and maintain watertight integrity of doors, hatches, and seals

Training and Procedures

• Ensure engine room crew is well-trained in operation and emergency procedures related to maneuvering
• Conduct regular emergency drills to test systems and crew readiness

Monitoring and Testing

• Utilize monitoring systems to track performance and condition of propulsion and steering systems
• Perform periodic turning tests, zig-zag tests, and stopping tests to assess maneuverability

By implementing these practices, you can help ensure that your vessel maintains optimal maneuverability, enhancing safety and efficiency during operations. Always follow company procedures, manufacturer recommendations, and relevant maritime regulations in your maintenance practices.

Seawater Splashing on Marine Motors: A Critical Issue

On ocean-going vessels, seawater splashing on motors presents a significant threat to the longevity and performance of marine electrical systems. This constant exposure to saltwater requires careful consideration and preventive measures.

Effects of Seawater Exposure

• Accelerated Corrosion: Saltwater rapidly accelerates corrosion in metal components, leading to premature deterioration.
• Electrical Short Circuits: As a conductor, saltwater can cause short circuits, potentially resulting in motor failure or fires.
• Reduced Efficiency: Gradual damage to windings and bearings can decrease motor efficiency over time.
• Insulation Breakdown: Repeated exposure can degrade motor winding insulation, causing electrical leakage and eventual failure.

Prevention and Protection Strategies

• Proper Enclosures: Utilize marine-grade, watertight enclosures for motors and electrical components.
• Strategic Placement: Position equipment away from splash-prone areas when possible.
• Regular Maintenance: Implement rigorous inspection, cleaning, and protective coating reapplication schedules.
• Corrosion-Resistant Materials: Opt for components made from materials like stainless steel or bronze.
• Protective Coatings: Apply marine-grade, water-resistant coatings to exposed surfaces.
• Proper Drainage: Ensure efficient systems for quick removal of splashed seawater.
• Cathodic Protection: Implement systems to prevent galvanic corrosion in metal components.

By adopting these measures, marine engineers can significantly mitigate risks associated with seawater splashing, enhancing the reliability and longevity of electrical systems on ocean-going vessels.