Answer EKM Question 4
Q4. With respect to Lubricating Oils used in Main Engine Sump: A. Briefly describe the causes and effects of bacterial attack on diesel engine lubricating oil. B. Bacterial activity has been detected in the lubricating oil of the main engine fitted in the ship aboard which you are serving as 2nd eng. Write a letter to the owner operator of the ship indicating the action you intend to take and offer suggestion to the avoidance of future incidents.
Answer: A. Describe the causes and effects of bacterial attack on diesel engine lubricating oil.
The term microbial degradation is sometimes referred to as biodegradation. It is the name given to the process whereby micro-organisms increase in number and decompose a hydrocarbon fuel or lubricant and eventually render it unfit for its duty.
This form of decomposition requires the presence of water together with other favorable environmental conditions including temperature, acidic conditions (pH value), and nutrients. With favorable environmental conditions the increase in microbial count may take place very quickly and cause rapid breakdown of the fuel or lubricant. In the case of lubricating oils the additives in the oil may function as the nutrients.
The indications of attack may be seen as follows.
(a) Creation of sulphurous gases having a smell similar to bad eggs.
(b) Build up of yellowish-coloured film on the inside of crankcases and the polished steel surfaces at the sides or unworn parts of bearings.
(c) The colour of the oil darkening.
(d) The oil tending to become opaque with a milky appearance.
(e) Inability of the lubricating oil centrifuge to separate water from the oil due to the creation of stable emulsions.
(f) Plugging of lubricating oil filters due to thick sludges.
(g) The effect of degradation usually shows up on bearings and bearing journals as a corrosive attack in the form of pitting in both the journal and the bearing, or a breakdown of the bearing surface. This may show itself as staining and in extreme cases as a breakdown of the bearing lining alloy.
(h) The effect of degradation usually shows up on bearings and bearing journals as a corrosive attack in the form of pitting in both the journal and the bearing, or a breakdown of the bearing surface. This may show itself as staining and in extreme cases as a breakdown of the bearing lining alloy.
Biocides and fungicides can be used to kill and prevent the spread of organisms within a distillate fuel oil. They can also be used in lubricating oils provided their use is approved by the oil supplier. Most of the treatments available cause some deterioration in the lubricating properties of the oil and their use should be carefully followed and observed.
The known organisms causing degradation are killed by preheating the lubricating oil to a temperature of 82.5°C during continuous separation treatment and when preparing to centrifuge the whole of the system oil charge.
Note The temperature at which lubricating oils are heated prior to centrifuging should never exceed the supplier's recommendations.
Care should be exercised in preventing leakage of cooling water into the system oils in both cross-head and trunk-piston engines. Modern non-toxic anti-corrosion additives may act as a nutrient to the organisms causing degradation.
some of the older additives are toxic to the organisms, but their use is banned in cooling systems used for heating low-pressure distilling plant producing portable water.
B. Letter to the Owner:
Subject:- Microbial degradation of Luboil, causes and remedial actions.
Good day sir,
This is in connection of the main engine sump lob oil Microbial degradation. As the ship was in dry dock and the main engine lube oil purifier was inoperative, following investigation and symptoms indicate microbial degradation of oil in crankcase. Symptoms:-
(a) Slimy appearance of the oil and also the slime tends to cling to the crankcase doors.
(b) Rust films.
(c) Honey-colored films on the journals, later associated with corrosion pitting.
(d) Black stains on White metal bearings, pins and jouinal.
(e) Corrosion of the purifier bowl and newly machined surfaces.
(f) Sludge accumulation in the crankcase and excessive sludge at the furifier discharge
(g) Paint stripping of the crankcase.
(h) Fouling smell all along the microbial contamination lubricants are:
(i) Additive,depletion.
(j) Rancid or sulphitic smells
(k) Increase in oil acidity or sudden loss of alkalinity.
(l) Stable water content in the oil which is not resolved by purifier.
(m) Filter plugging in heavy weather
(n) Reduction of heat transfer in coolers.
Remedial action:
(a) We have ensured that the water content of crank case oil does not rise above 0.5 per cent by weight.
(b) We have extended the suction of the purifier further down towards the bottom of the sump to circulate the settled sludge through the purifier as recommended by the purifier manufacturer and the engine manufacturer as well.
(c) Lube oil feed temperature of the purifier is maintained above 87-89.0 at all time.
(d) Lube oil purifier was opened up and overhauled and continuous operation of the purifier on the mine engine sump is ensured and the ship crew is advised to monitor the purifier operation closely.
(e) We have checked and ensured that the coolant corrosion inhibitor concentrations are at the manufacturer's recommended values.
(f) We are continuously monitoring the microbial population of the cooling water and prevent any water leaks into the oil system.
(g) Test for microbial contamination of the oil after the purifier is sterile.
(h) Care is taken to prevent any ingress of contaminated bilge water.
(i) Lube oil storage tanks are continuously drained to remove any condensed water.
lf the conditions don't improve:
(a) If the condition doesn't improve over time and no positive improvements seen, we will have to take the complete oil into renovating oil tank and treat as time permits during a long anchorage or a port stay with the consent of the master and other harbour personnel.
(b) Oil to be transferred to the renovating oil tank, run purifier tank to tank and heat up the lube oil to 90°C and continuously circulate the oil through the purifier system for 24-48 hours.
(c) We will also follow the tube oil suppliers procedures in treating such oil with additives supplied and inject the conditioner provided by them and follow all their recommendations curing bacterial attacked oil.
(d) After 48 hours the oil can be pumped via purifier to the sump, run the purifier until 80% of the tank and stop transfer, for the remaining of 20% of the oil, fresh lube oil shall be used as the fresh lube oil additives will help the reminder with further curing and properties enhancement.
Answer: A. Describe the causes and effects of bacterial attack on diesel engine lubricating oil.
The term microbial degradation is sometimes referred to as biodegradation. It is the name given to the process whereby micro-organisms increase in number and decompose a hydrocarbon fuel or lubricant and eventually render it unfit for its duty.
This form of decomposition requires the presence of water together with other favorable environmental conditions including temperature, acidic conditions (pH value), and nutrients. With favorable environmental conditions the increase in microbial count may take place very quickly and cause rapid breakdown of the fuel or lubricant. In the case of lubricating oils the additives in the oil may function as the nutrients.
The indications of attack may be seen as follows.
(a) Creation of sulphurous gases having a smell similar to bad eggs.
(b) Build up of yellowish-coloured film on the inside of crankcases and the polished steel surfaces at the sides or unworn parts of bearings.
(c) The colour of the oil darkening.
(d) The oil tending to become opaque with a milky appearance.
(e) Inability of the lubricating oil centrifuge to separate water from the oil due to the creation of stable emulsions.
(f) Plugging of lubricating oil filters due to thick sludges.
(g) The effect of degradation usually shows up on bearings and bearing journals as a corrosive attack in the form of pitting in both the journal and the bearing, or a breakdown of the bearing surface. This may show itself as staining and in extreme cases as a breakdown of the bearing lining alloy.
(h) The effect of degradation usually shows up on bearings and bearing journals as a corrosive attack in the form of pitting in both the journal and the bearing, or a breakdown of the bearing surface. This may show itself as staining and in extreme cases as a breakdown of the bearing lining alloy.
Biocides and fungicides can be used to kill and prevent the spread of organisms within a distillate fuel oil. They can also be used in lubricating oils provided their use is approved by the oil supplier. Most of the treatments available cause some deterioration in the lubricating properties of the oil and their use should be carefully followed and observed.
The known organisms causing degradation are killed by preheating the lubricating oil to a temperature of 82.5°C during continuous separation treatment and when preparing to centrifuge the whole of the system oil charge.
Note The temperature at which lubricating oils are heated prior to centrifuging should never exceed the supplier's recommendations.
Care should be exercised in preventing leakage of cooling water into the system oils in both cross-head and trunk-piston engines. Modern non-toxic anti-corrosion additives may act as a nutrient to the organisms causing degradation.
some of the older additives are toxic to the organisms, but their use is banned in cooling systems used for heating low-pressure distilling plant producing portable water.
B. Letter to the Owner:
Subject:- Microbial degradation of Luboil, causes and remedial actions.
Good day sir,
This is in connection of the main engine sump lob oil Microbial degradation. As the ship was in dry dock and the main engine lube oil purifier was inoperative, following investigation and symptoms indicate microbial degradation of oil in crankcase. Symptoms:-
(a) Slimy appearance of the oil and also the slime tends to cling to the crankcase doors.
(b) Rust films.
(c) Honey-colored films on the journals, later associated with corrosion pitting.
(d) Black stains on White metal bearings, pins and jouinal.
(e) Corrosion of the purifier bowl and newly machined surfaces.
(f) Sludge accumulation in the crankcase and excessive sludge at the furifier discharge
(g) Paint stripping of the crankcase.
(h) Fouling smell all along the microbial contamination lubricants are:
(i) Additive,depletion.
(j) Rancid or sulphitic smells
(k) Increase in oil acidity or sudden loss of alkalinity.
(l) Stable water content in the oil which is not resolved by purifier.
(m) Filter plugging in heavy weather
(n) Reduction of heat transfer in coolers.
Remedial action:
(a) We have ensured that the water content of crank case oil does not rise above 0.5 per cent by weight.
(b) We have extended the suction of the purifier further down towards the bottom of the sump to circulate the settled sludge through the purifier as recommended by the purifier manufacturer and the engine manufacturer as well.
(c) Lube oil feed temperature of the purifier is maintained above 87-89.0 at all time.
(d) Lube oil purifier was opened up and overhauled and continuous operation of the purifier on the mine engine sump is ensured and the ship crew is advised to monitor the purifier operation closely.
(e) We have checked and ensured that the coolant corrosion inhibitor concentrations are at the manufacturer's recommended values.
(f) We are continuously monitoring the microbial population of the cooling water and prevent any water leaks into the oil system.
(g) Test for microbial contamination of the oil after the purifier is sterile.
(h) Care is taken to prevent any ingress of contaminated bilge water.
(i) Lube oil storage tanks are continuously drained to remove any condensed water.
lf the conditions don't improve:
(a) If the condition doesn't improve over time and no positive improvements seen, we will have to take the complete oil into renovating oil tank and treat as time permits during a long anchorage or a port stay with the consent of the master and other harbour personnel.
(b) Oil to be transferred to the renovating oil tank, run purifier tank to tank and heat up the lube oil to 90°C and continuously circulate the oil through the purifier system for 24-48 hours.
(c) We will also follow the tube oil suppliers procedures in treating such oil with additives supplied and inject the conditioner provided by them and follow all their recommendations curing bacterial attacked oil.
(d) After 48 hours the oil can be pumped via purifier to the sump, run the purifier until 80% of the tank and stop transfer, for the remaining of 20% of the oil, fresh lube oil shall be used as the fresh lube oil additives will help the reminder with further curing and properties enhancement.
Comments
Post a Comment