January 11, 2005 at 12:45 am #4396
Our older plant has been experiencing harder than normal coke and as a result we are seeing cutting times as long as 6 hours. A large part of the lengthy cutting interval has to do with the realatively low (by design) cutting pressures. Has anyone optimized thier cutting tool nozzle sizes to match the drum size and composition of coke produced? Our drums are 26ft in diameter, and I’d be most interested in finding out what any of the other users are running for nozzle sizes, the type of coke produced, plus at what pressure and flow they typically cut at. We are presently looking at drafting a reasearch proposal to map the force density within the spray pattern at various distances up to a 13 foot radius. We are also looking at optimizing the spray pattern to increase the force density at the perifery of the drum where cutting is particularly difficult.
January 19, 2005 at 10:48 pm #7868
I don’t know about the nozzle sizing for increasing water pressure. I have heard that there are basically two pattern designs. One design has the final cut pattern angled. I think it is set at about a 10° angle to allow for more of a cut and wash pattern. This is good for sponge coke to softer and shot coke. For harder coke to needle coke, a straight across cut pattern (no angle) is better. [;)]
January 26, 2005 at 1:38 pm #7862
We 6 drums total – 2 are 27′ in diameter and 4 are 20′ in diameter. Our jet pump for the 27′ drums has a discharge pressure of about 3400 psi and a flow of about 900 gpm. Nozzle diameters on our combo tool is 0.565″
The jet pump for the 20′ drums puts out about 1950 psi but we don’t have flow indication for this pump. The spec sheet for the pump says we should be putting out 800 gpm but I’d be surprised if we are actually that high. Use of a strap on doppler flow meter has put us at around 650 gpm. The nozzle diameter for these combo tools is 0.498″. We also were struggling with long cuts on this coker last summer and did all kinds of feed analysis to determine why the coke was so hard. We finally decided to experiment with the nozzle sizes on one combo tool to see if that would help. When we disassembled the tool in the shop we found that almost 50% of the orifices in the flow straightener were plugged with pea sized pieces of coke. How these small pieces made it through our cutting water tank and jet pump is beyond me but they were there none the less. We still decided to go ahead with the different size nozzle so we put one or our spare 0.565″ nozzle sets on this bit. The jet pump pressure with this bit is about 1820 psi – again flow is unknown. Once we went through all the other combo tools and cleaned them out our cutting times returned back to normal – down from 5 hours back to 2-3 hours.
January 29, 2005 at 3:27 pm #7860
conatct your cutting tool rep he should be able to supply the diameters of your cutting nozzles make go-no- go gauges out of scrap steel for checking, I done this and it takes 5 minutes to check nozzles
March 27, 2006 at 1:16 pm #7630
Contact me and I can help. Flowserve has years of data on this and we can make sure you have the correct size based on drum dia, pressure and coke type and VCM.
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