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Evan Hyde

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  • in reply to: U bends too small in heater #31464

    Evan Hyde
    Keymaster

    Interesting, what % of ID restriction can you accommodate?

  • in reply to: Refinery Sludge injection #31463

    Evan Hyde
    Keymaster

    Hi. Clean Harbors has done it in the past but their business units have changed so I’m not sure if they are still doing it. There was a company in Chile that I met a few year ago that was doing pigging for all of S. America and some waste treatment as well…you might check with them. Sorry…name escapes me I’m sure there are only a few in S. America….maybe you can add the name if you recall.

  • in reply to: DCU Flare #31374

    Evan Hyde
    Keymaster

    You might consider routing the off gas from the treatment unit back to the DCU heater. I have worked with a few plants that have a burner specially designs for this stream. It needs to be handled carefully from a design and interlock perspective. But it can be a shorter run than to the the SRU and reduce the risk of plugging. But I agree with the earlier comments from Mike that the water and loading are the primary causes of issues.

  • in reply to: How often does industry replace coke drums? #30979

    Evan Hyde
    Keymaster

    7000 cycles is a typical number before the first crack IF, big IF…you do everything right. Most sites do not. So experience varies from cracks after 3 years to barely any after 30+ years. Tons of factors at play here….material, fabrication, operator/process, etc. Also coke drums can be repaired indefinitely for a price of course with automated, engineered weld overlay. Some operators will replace drums after 15~ years while others are still going strong after 30-40 years with repairs….it is an engineering desicison and a economic one. No simple answer…but 7000 cycles is a good rule of thumb to start to expect cracking.

  • in reply to: Managing Coke Drum Foam with Chemicals #31508

    Evan Hyde
    Keymaster

    Not sure I fully understand your question, please clarify.

    Carrier+AF can be injected intermittently based on level provided you are getting good knock down results. However, if the foam is tenacious and not responding the injection, generally people leave it in once started. If the foam layer is growing faster than ‘normal’ then multiple dosing pumps are started.

  • in reply to: Managing Coke Drum Foam with Chemicals #31507

    Evan Hyde
    Keymaster

    The flow of AF is done generally with a metering pump and no direct flow measurement. This is most common in older style units. With newer units and more automation, corriolis and direct flow control is a good idea but still less common.

  • in reply to: Managing Coke Drum Foam with Chemicals #31506

    Evan Hyde
    Keymaster

    60k is relatively low on the scale as you learned in the webinar. Therefore, it is generally injected for longer and higher concentrations relative to carrier. Typically 20-50:1 for 4-6h in the cycle in plants that are using this type of material. What is your dosage and duration? Please share if you can.

  • in reply to: Managing Coke Drum Foam with Chemicals #31505

    Evan Hyde
    Keymaster

    This is a very interesting question and it has come up in one of our most recent projects. Almost all the cokers we have worked with, the carrier+AF is mixed near grade. Then there is a lag between this point and the actual injection point. Moving the mix point to the cutting deck seems like a smart option. Then you could very quickly adjust the dosage ratio.

    Has FW done this? Results?

  • in reply to: Managing Coke Drum Foam with Chemicals #31503

    Evan Hyde
    Keymaster

    Yes, this is a good emergency strategy to reduce foam quickly but you have to be very careful when opening the system back up as the foam can re-appear just as quickly as it goes….

  • in reply to: Managing Coke Drum Foam with Chemicals #31501

    Evan Hyde
    Keymaster

    There is no simple answer to this question as it was presented. There are various strategies from time to Level based to start injection. But consensus is generally to keep it going after switch until the steam to blowdown has started.

    There is always some fines entrainment to the fractionator at the end of filling. Managing over time is the key to long term reliability. But if entrainment for 1 cycle is higher than normal, yes additional AF injection would be a good idea.

  • in reply to: Managing Coke Drum Foam with Chemicals #31499

    Evan Hyde
    Keymaster

    If you are in a true form over situation, the carrier probably will not help. But if you are trying to suppress the phone before the carryover is massive, it might help. But anti-foam in large doses, running multiple pumps simultaneously, is the best that

  • in reply to: Managing Coke Drum Foam with Chemicals #31498

    Evan Hyde
    Keymaster

    Because the system is used intermittently, I think it would be hard to put a alarm on pressure or flow because the alarm would be in state when the system is turned off. But if you have a system that would allow you to make the alarm smart and only active when Diane iPhone should be going or at certain points on the cycle then this could be possible. Otherwise the operator can just watch it

  • in reply to: Managing Coke Drum Foam with Chemicals #31497

    Evan Hyde
    Keymaster

    I do not think this is common but could be possible only at a very high flow rates of anti foam. I have never seen it happen but it seems plausible

  • in reply to: Managing Coke Drum Foam with Chemicals #31495

    Evan Hyde
    Keymaster

    I’ve only see the skid on the ground. I have seen a emergency injection tank on the cutting deck

  • in reply to: Managing Coke Drum Foam with Chemicals #31489

    Evan Hyde
    Keymaster

    Generally speaking, higherMW (cSt) antifoam does have better performance. You have to weigh the additional cost vs the additional performance vs your foam needs to come up with the optimum for your site.

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