Hi every body, I have a problem that make me headache.

My Gas Plant has Fire Caterpillar Diesel Engine 3208; 280 HP; Turbocharger; Oil cooler; water from discharge pump flow to cool coolant of Engine. Fuel solenoild, and water solenoild is controled by battery. Engine has only 01 compression ring and 01 oil ring of each piston. It total running is 200 hours that each time running about 5 minuties.

One day, after running 4 minuties, much oil and smoke jet out seriously through oil stick and air filter continuously. Operator stop engine immediately but engine can not stop by swtich so that operator shut off fuel valve to stop engine.
I had changed new piston ring, piston, bearing connect rod beacause it be damaged; check all intruments, fuel solenoild , regulator temperature, water solenoild is good condition and overhaul Turbocharger. After finishing, Engine had run during 20 hours continuously and it is OK.

However the next week after running 4 minuties, this phenomenon was repeated but amount of oil and smoke jet out was less than of last time. And it also can not be stop by switch and have to stop by shutting fuel line. Immediately after that, Engine was started and it has no proplem and it be OK tll now.

Please explain me about this problem and the way to prevent it happen again!
Im am very appreciate yours consideration!

Have you cleaned and/or changed the flame traps?

Look like your failure mode is fail to stop. Have you checked the button on the local control panel?

What is your operating regime?

From your post I suspect that the engine has run 4 years, with very short daily operating times 4 -10 minutes.
If the engine has no time to warm up, failures will appear, I imagine around the 2400 start-stops this engine has suffered.

In a lot of engines, the emergency stop activates a device to close the air inlet, especially where flamable gases could be present.

Hullo Nguyen Ba Triet,
As Steven has surmised I think short runs are the problem It is not good operating practice to run diesel engines for very short periods, especially on low or no loads. What happoens is that the engine runs cold, allowing carbon particles to deposit on all cold areas, including piston ring grooves, exhaust valves and manifold etc. When you open the cylinder head, you should expect to see hard carbon deposits in all these places. Sometimes you will have to use a chisel to remove the deposits.
These carbon particles 'light up' when the engine starts and act like glow plugs, causing erratic ignition (at the wrong time in the cycle). That is when you get these big puffs of smoke, backfiring, blowby past piston ring into the crankcase etc.
The solution is therfore quite simple. After you do a top end overhausl(to decarbonise it), make sure you run the diesel engine less frequently, but at least 4 hours at a time, on full load. For this you may have to open one or two fire hydrants at the far end of the Plant. That will also help flush out the lines.

This message has been edited. Last edited by: Vee,

Hi every body, thank you very much for your answer!
Continue to Fire Engine Cat diesel, I supply more information that Engine has heater and Engine alway is heated at 60C degrees all day.Certainly,that problem just only occur at the third or fourth in immediately thereafter Start times sequence. May be that problem come from Turbochager or when Engine running but Solenoild in auto water line is closed by electrict trouble that cause overheat for Engine?

Nguyen Ba Triet

Hello Nguyen,
This may be an obvious question, but what colour is the smoke?

You also said the oil/smoke was coming out of the oil filler/dipstick and the air filter?

As Vee suggested, have you removed the cylinder head to clean off any carbon deposits?

A block heater at 60C will assist starting in low ambient temperatures I don't believe it will be much use in reducing condensation from the intake charge if the engine never heats up. I would want engine jacket coolant temperatures to be over 80C before expecting any protection from condensation.

Matt.

Hello every body !

The smoke that inspected at air filter and dipstick is very dark; many dark deposits in intake piping,air filter but the more go inside the less deposits. After having this problem,I removed piston, piston ring, cylinder head, intake piping and exhause piping to clean off any carbone deposits. However this problem was repeat at second times.

Thank you for yours answer.

One question Nguyen Ba Triet, " do you run this engine every day?"

Hi Mr Steven!
Engine run at least one time per day during 5 minuties. As soon as this problem happen, I opened the cylinder head to inspect but every thing is very clean. So I do not think this problem cause by erratic ignition or deposit!
Now I am not clear obout this matter.
I am appreciate for yours answer!

Ba Triet you are killing the engine.

Industrial engines are meant to be run fully loaded, it are not madames that are sitting in a tea salon.
It took us also a great time to convince the "brains" in our company otherwise

Why do you have to run it daily? For fire safety, you can refer to NFPA25 which recommends weekly test run and annual capacity test. Also refer to Catepillar engine manual for minimum running time to prevent carbon deposit.

Nguyen Ba Triet,
Steven has hit the nail on its head. You need to
1. Decarbonize the engine properly, incl. pistin ring grooves, exhaust manifolds etc.
2. Test run the engine no more than once a week (two weeks is better, if local laws permit it)
3. Run it each time for 4-6 hours ON FULL LOAD, never on no load.
After you change your test regime, observe its performance for 3-6 months. If you dont find a great improvement, let us discuss all this again. Meanwhile dont touch the turbocharger!

Hello Nguyen,
I have talked to a couple of the old hands (older than me, anyway) around here for some more information.

Apparently the two ring 3208 piston could suffer from oil control problems. Considering your engine never warms up this is possible.

Based on your description of oil and smoke it sounds like you have lost oil control and the engine is suffering severe blowby.

Also, if the engine has a closed circuit ventilation system, it is possible the engine intake system is injesting oil from the blowby problem and "running on" after you shut it down.

Perhaps you could have a technician investigate whether this is the case.

You could contact the Cat dealer and see whether you can fit a three-ring piston for better oil control into your engine (they are available for certain applications).

If the bores of the engine are glazed from cold running they will need to be honed to re-establish oil control.

As per Steven's and Vee's suggestion, you really need to run this engine at full load and have it warmed up.

Let us know what you find.

Matt McLeod.

What do you guys mean by running the engine at FULL LOAD? Is it running it at full flow condition through the whole firefighting line and discharge at the farthest fire hydrant? In the NFPA25, the weekly test run is at no flow condition ie flow through a relief valve to overboard/shortcut line whereas the annual capacity test is at flow condition through the whole system.

This message has been edited. Last edited by: Josh,

Josh how are the firewater engines tested at your plant?

1) You can wash LPG/LNG bullets with the sprinkler system, this way you can clean the bullet and rinse the sprinklers, preventing them from clogging.
2) You can fight bees at high places using a hydrant monitor (instead of the traditional torch)
3) You can flush the lines of the system and check if somebody has closed a block valve rendering a branch inactive when needed (Murphy's Law)
4) Conduct a fire drill on lazy sunday afternoon when there is nothing to do, and everything is running smooth (my favorite)
6) When it is very dusty you can lay a water curtain to get rid of the dust.

These are all methods to test the system's integrity and keep people alert in using it when needed.
The NFPA code is good, but it is on paper, I think that every refinery has this code, and can show it when there is a safety audit. But what good is the code if the operator don't know to handle the equipment?

We test run weekly, to flow through a relief valve whose outlet is connected to an overboard line to find out whether it can start or not (failure finding).

This message has been edited. Last edited by: Josh,

Certainly we can use fresh water for those purposes you mentioned above but will you do the same with seawater?

In your refinery, do you have only freshwater for fire fighting? Are your freshwater fire pumps complimented by a seawater pump in case you run out of freshwater?

This message has been edited. Last edited by: Josh,

Sure we can combine fire water pump testing with fire fighting drill using the scenarios you mentioned above. But if it's weekly or bi-weekly for 4 to 6 hours, won't it be costly? Or is it free because you collect rain water in ponds inside the refinery?

How often is your fire drill? Every week, monthly or quarterly?

This message has been edited. Last edited by: Josh,

In my previous plant, fresh raw water is expensive and we reserve for process utility purposes.

In offshore, we only use seawater for firefighting purposes.