Novachris
Well-Known Member
could you use white diesel, not much price difference and I know the engine is supposed to run hotter on the stuff, but would it be worth a try after you cleaned the tanks out?
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Diesel Bug
- Thread starter Nicholas123
- Start date
Nicholas123
N/A
The bacteria that cause diesel bug (and any other form of hydrocarbon bug) come out of the well with the crude. They have been hanging around there for millions of years, have undergone a distillation and cracking process at the refinery at temperatures up to 200 C, pressures up to 40 bar in some cases along with various chemical processes. They have survived that without apparently being the slightest bit affected. Mankind's history of coping with infectious bacteria is not exactly exemplary on a far smaller scale. So how would you suggest they be destroyed in an industrial process?
That's interesting info about the bacteria but it seems to me that you are asking the wrong person that question I am not an Industrial chemist.How about you ask the experts working for the oil refineries & if adding proprietary brands of additives is the solution why they do not do that at source. After all they would be able to get a big discount for doing it in bulk?
Nicholas123
N/A
could you use white diesel, not much price difference and I know the engine is supposed to run hotter on the stuff, but would it be worth a try after you cleaned the tanks out?
I presume according to vyv_COX posting the same refinery problems are there unless it has the additives?Do cars & lorries suffer from the same problems?
jdc
Well-Known Member
I presume according to vyv_COX posting the same refinery problems are there unless it has the additives?Do cars & lorries suffer from the same problems?
I can't answer for lorry fleets, but can for the farm. We have ~2000 litre red diesel tank which is ancient and never gets cleaned. We make no attempt to keep it near full (as that just leaves more for the gypsies to come and steal - and I speak from bitter experience). I've never drained the tank yet if condensation were to form surely it would be in this tank.
We run 4 tractors from this with not too great a turn over of fuel as it's not arable so the tractors are only on general duties or pasture topping etc (another thread could come out of this on the non-effects of idling all day under little load...)
We have never found any diesel bug, nor more than a few droplets of water nor had any other fuel issues (other than theft). We just change the CAV filters once a year (which is between 600 - 1000 hrs). Some black sludge does form, but afaik it's just heavy residues and I suspect still hydrocarbons rather than a bug.
The difference is of course that the farm yard doesn't beat to windward! But nonetheless I'm unconvinced that the problem of diesel bug is that widespread or severe, which is maybe why refineries and distributors are unwilling to take action - why should they take precautions against the man in the moon being made of green cheese?
The thing which does worry me a lot on the boat is that the diesel filler cap is on the side deck and when on passage spends days under green water. I have become fairly meticulous about changing the O ring in the filler cap, but still it's a weak point: I wonder if boats suffer water contamination simply due to immersion of the filler and breathers more than from condensation or poor fuel?
Swanrad2
Well-Known Member
I started reading the thread because I have a gunged diesel system that I am cleaning, so practically, the suggestion has been made to me that some of the black stuff might make it through the filters. The belt and braces treatments unbeaten by a mechanic is to blow the fuel pipes clear away from the engine using a compressor. Change the filters, clean the tank and shock treat with new diesel. The same mechanic also tells me cars left for long periods between uses also make water and gunge.
I have also been pondering the argument about condensation and volume of air being insufficient to explain the water in fuel tanks within a closed system. I wondered if:
1) New 'wet' air is sucked in when fuel is used (obviously) and when water condenses out of the existing air - if I remember correctly this will lower the pressure within the tank and suck in new air
2)New wet air can diffuse in (Flick's law I think) - really similar to 1) part b
3) Changes in atmospheric pressure will mean the tank breathes in and out - the maths of this one are too hard for me, it would be the change in volume of air within the tank and the volume of the breather tube I think.
My head hurts.
I have also been pondering the argument about condensation and volume of air being insufficient to explain the water in fuel tanks within a closed system. I wondered if:
1) New 'wet' air is sucked in when fuel is used (obviously) and when water condenses out of the existing air - if I remember correctly this will lower the pressure within the tank and suck in new air
2)New wet air can diffuse in (Flick's law I think) - really similar to 1) part b
3) Changes in atmospheric pressure will mean the tank breathes in and out - the maths of this one are too hard for me, it would be the change in volume of air within the tank and the volume of the breather tube I think.
My head hurts.
Swanrad2
Well-Known Member
I can't answer for lorry fleets, but can for the farm. We have ~2000 litre red diesel tank which is ancient and never gets cleaned. We make no attempt to keep it near full (as that just leaves more for the gypsies to come and steal - and I speak from bitter experience). I've never drained the tank yet if condensation were to form surely it would be in this tank.
We run 4 tractors from this with not too great a turn over of fuel as it's not arable so the tractors are only on general duties or pasture topping etc (another thread could come out of this on the non-effects of idling all day under little load...)
We have never found any diesel bug, nor more than a few droplets of water nor had any other fuel issues (other than theft). We just change the CAV filters once a year (which is between 600 - 1000 hrs). Some black sludge does form, but afaik it's just heavy residues and I suspect still hydrocarbons rather than a bug.
The difference is of course that the farm yard doesn't beat to windward! But nonetheless I'm unconvinced that the problem of diesel bug is that widespread or severe, which is maybe why refineries and distributors are unwilling to take action - why should they take precautions against the man in the moon being made of green cheese?
The thing which does worry me a lot on the boat is that the diesel filler cap is on the side deck and when on passage spends days under green water. I have become fairly meticulous about changing the O ring in the filler cap, but still it's a weak point: I wonder if boats suffer water contamination simply due to immersion of the filler and breathers more than from condensation or poor fuel?
Found this forum post for trucks
http://www.dieseltruckresource.com/dev/archive/gravity-feed-cutting-small-tube-t266615.html
Would one of the three way valves mentioned (or just a shut off/solenoid) below the decks not ease your worries?
NormanS
Well-Known Member
I don't know anything about the bug, but I do know that water is substantially heavier than diesel, so if your tank has a sump and a drain, you have very little to worry about. In that respect boat tanks have a clear advantage over stationary tanks, as the movement of the boat encourages any dirt or water to gravitate into the sump.
jdc
Well-Known Member
Asphaltene?
A few minutes on Google turns up myriad sources stating (but just stating - I haven't yet found a scientific paper describing the test method) that 90% of fuel contamination is alphaltene, not due to biological activity at all. This (asphaltene) is both naturally occurring and a product of the re-polymerisation and oxidation of stored fuel. Its production is exacerbated by passing fuel through diesel engines, thereby heating it, and returning it to the tank - ie exactly what most yacht systems do. The cracking process in the refinery - remember from school geography (or was it chemistry?) - breaks such heavy hydrocarbon chains down (ie cracks them) , but they re-form slowly, especially if heated, agitated and exposed to oxygen.
Treatment with biocides can, according so some sources, make the problem worse by encouraging flocculation and thus precipitation.
So actually many (90%?) of all observed filter clogging problems may be simply due to the the chemical (in)stability of fuel - a problem inherent to Cn - H(2n+2) and nothing to do with bugs at all.
If passing it through the engine and back to the tank is deleterious, then a system with a 'day tank' into which the return goes, fed in turn from the undisturbed main tank, might be better. There should be empirical evidence for this, if true. It's effectively what happens with tractors. Cars, if I understand correctly, usually have a different injection method and don't return fuel to the tank.
A few minutes on Google turns up myriad sources stating (but just stating - I haven't yet found a scientific paper describing the test method) that 90% of fuel contamination is alphaltene, not due to biological activity at all. This (asphaltene) is both naturally occurring and a product of the re-polymerisation and oxidation of stored fuel. Its production is exacerbated by passing fuel through diesel engines, thereby heating it, and returning it to the tank - ie exactly what most yacht systems do. The cracking process in the refinery - remember from school geography (or was it chemistry?) - breaks such heavy hydrocarbon chains down (ie cracks them) , but they re-form slowly, especially if heated, agitated and exposed to oxygen.
Treatment with biocides can, according so some sources, make the problem worse by encouraging flocculation and thus precipitation.
So actually many (90%?) of all observed filter clogging problems may be simply due to the the chemical (in)stability of fuel - a problem inherent to Cn - H(2n+2) and nothing to do with bugs at all.
If passing it through the engine and back to the tank is deleterious, then a system with a 'day tank' into which the return goes, fed in turn from the undisturbed main tank, might be better. There should be empirical evidence for this, if true. It's effectively what happens with tractors. Cars, if I understand correctly, usually have a different injection method and don't return fuel to the tank.
Last edited:
Nicholas123
N/A
It just seems to go on getting more & more confusing http://www.ybw.com/forums/showthread.php?380473-Cars-now-suffering-from-Diesel-Bug
I am wondering if I should just drain the tank.Drain out the water in the separator & bleed out the fuel line as close to the engine as possible using the little pump you use to bleed the system.Leaving the whole system dry until the spring.What does the panel think?
I am wondering if I should just drain the tank.Drain out the water in the separator & bleed out the fuel line as close to the engine as possible using the little pump you use to bleed the system.Leaving the whole system dry until the spring.What does the panel think?