This topic contains 2 replies, has 1 voice, and was last updated by Anonymous 10 years, 4 months ago.
May 22, 2012 at 6:32 pm #1863
We have a drum that will not drain. We have attempted to steam the inlet (numerous times) and we have blasted it with quench water. Steam and water have no trouble entering the drum, as indicated by our K-Rays and visuals from the top head, however nothing wants to come out. Our drain line is not plugged. We know this because we hooked-up a flex hose to our drain line and ran it to the coke pit and we were able to pass steam through. The issue seems to be in the drum. Any ideas on how to drain this coke drum?
May 22, 2012 at 8:36 pm #4630
This can be a very serious safety hazard. It sounds like you have the top head open on a drum that has not been drained, so there is a hazard from the top head as well as the bottom head. You should keep personnel away from both the bottom and the top head until the drum is safely drilled out.
If you have tried steam and water through the fill line and are not able to get the drum to drain, then about the only option is to drain through the bottom head. You do not state what type of bottom head closure you have on your Coker. If you have a DeltaValve or Z&J valve as a bottom head, you could remove people from the drum structure and away from the pit or pad for about 100 meters radius and then open the slide valve. The top head will need to be open to prevent a vacuum from being formed when the water and coke does exit the drum. Once the heads are open, then you can drill a pilot hole through the drum that will drain water, if it has not drained before then. Be aware that this drum may have significant hot spots that could cause a blow out or an eruption, so having the area cleared of people and equipment is important.
If the bottom head is a semi-automatic style, you need to evaulate if the cart can hold a drum full of water. Only if that is true should you attempt to have personnel remove most of the bolts. Some operators have left as many as 8 bolts in the head that have been loosened enough to let the bottom head drop only slightly. Once personel are a significant distance away from the drum should you attempt to lower the bottom head remotely. Once the water has stopped draining through the bottom head, run the cart back up and have the last bolts removed and then again have people a significant distance away before lowering the bottom head completely.
The hazard at the top of the drum is from a boil over. If there is a hot spot in the drum that can cause rapid vaporization of the liquid water, the resulting steam can eject hot water out of the top of the coke drum.
Understand that very serious injuries including fatalities have occurred from hot water associated with drums that did not drain properly so this is a very serious safety hazard. These types of activities should only be attempted after a thorough discussion with all the personnel involved.
May 23, 2012 at 11:21 pm #4629
We dehead our drum by physically revoming the bolts and using a carriage. I suggested what you say, to move the cart in, loosen some bolts, and slightly drop the head. The fear is that the carriage will not be able to hold that much weight. I also forgot to mention that we were on low rates. Our drums were requiring roughly 130’000 bls of water to reach the middle K-Ray. On this drum the K-Ray rang in at 75’000 bls. There is a fear that the drum is not properly quenched. There is the possibility that if we are able to drop the head slightly that bitumen could ooze out. At that point we would no longer be able to put the bottom head back on, and would be in a worse place.
So far we have used 150 steam quench and water (using the quench pump) in the attempt to free up the plug. We have also tried to pressuring up the drum to 30psi and attempt to drain. It was unsuccessful.
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