July 19, 2017 at 3:35 am #26794
We are having coke cutting system supplied by M/S flowserve.Recently we are facing frequent problem of cutting tool mode operation and each time flow serve provide the reason of high concentration of coke fines in cutting water (2000ppm-10000ppm) .We took sample from the cyclone outlet and gets 20ppm concentration of particulate.Is there any other point from we should take sample or suggest any technique to clean the coke cutting water.
July 19, 2017 at 12:07 pm #26799
gary m pitmanParticipant
Sorry to hear you are struggling with coke cutting deepesh1534.
I’ve been to more than 100 cokers, and everyone has issues with coke fines.
Some items that may affect the amount of coke fines in the cutting are:
· The crude slate.
· The coil outlet temperature which can make the coke dusty, sandy, ash like and generates fines.
· Coke cutting techniques. If you pulverize the coke with the cutting system, you make more coke fines.
· Configuration of the cutting water recycling system (the maze).
· Cycle time – is there enough time for the coke fines to settle out in the maze?
· How often is the maze cleaned to reduce the buildup and allow the channels to work properly?
· Most cutting water tanks have an agitation and drain system. Is that being used on a routine basis?
· Pull samples at the jet pump suction at different times of the coke drum cycle as a base point for comparison throughout the water flow.
· Issues with the cutting tool operation requires more investigation. There may be other issues affecting that.
I highly suggest using an Infrared (IR) camera to take a picture of the side of the jet tank to show the level of the coke in the jet tank.
You can focus your analysis in the areas I listed above. If you would like me to go into more details about your specific site, you can reach me, Gary Pitman, directly on the contacts (https://refiningcommunity.com/contact/) page.
July 24, 2017 at 8:36 pm #26861
I would recommend taking a sample of the coke drum quench water at the discharge of the quench water pumps. As Gary indicates, having the maze be routinely dredged to remove the solids in the build up to allow adequate time for the solids to settle out in the maze is critical to having low solids content in the cutting water. Routinely agitating the cutting water tank and draining the solids back to the coke pit on a regular basis is needed to keep a low inventory of solids in the cutting water tank.
If you have samples of the water out of the cyclones that are at 20 ppm suspended solids and more than 2000 ppm suspended solids in the cutting water, you should take samples of the water coming out of the maze throughout the drum draining and drilling cycle to determine where the solids breakthrough is occurring.
July 25, 2017 at 10:37 pm #26894
Thanks for valuable respond..but i would like to know the concentration of particulate in jet pump (Coke cutting pump) outlet which goes to cutting tool and what recommended value of particulate concentration for cleaning the water..
July 28, 2017 at 6:29 pm #26914
My assumption is that the coke drum water storage tank is common for the drum quench water and for the drum cutting water. Taking as sample off of the quench water pumps is easier than taking it off of the suction of the cutting water pump.
I believe it is generally acceptable to have a suspended solids content in the cutting water system of up to 500 ppm without excess erosion or plugging or equipment wear. Above 2000 ppm suspended solids is very dirty water and the cutting water system will experience plugging, erosion, equipment wear and poor system reliability. In between these two values, the issues are the same, just less severe.
It is possible to maintain the cutting water solids content at less than 100 ppm suspended solids with proper management of the maze and routine purging of the cutting water storage tank. I think the benefits of going lower than 100 ppm suspended solids are limited. If you can get there, lower solids is better.
Flowserve and RuhrPumpen have guidance on the suspended solids content the cutting water should contain, so you should consult them on this problem.
August 7, 2017 at 12:56 pm #27137
Deepesh1534, could you give us more details about your problem with the coke cutting system?
We change the drills every 6 month ant the rotor of the Jet Pump every 12-18 months. We manage around 500 ppm of solids.
We are developing some minor project to improve the confiability of the system.
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