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Mercaptain sludge

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Eric_25
Eric_25 Member Posts: 79
in THE MAIN WALL
Anyone have a solution for mercaptain sludge raising havoc with a couple of rooftop boilers, at least that is what we are assuming it is. This system has been running for a few years about 1.2M net output total. There are drip tees installed where required and the piping all looks good size wise etc. but we plug up the burner orifices and have sticking gas valves way too often. any ideas?

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  • Ed_26
    Ed_26 Member Posts: 284
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    sludge

    Check the regulators, they tend to gather the sludge & oils. If they are close to the units, & warm enough, it will pass thru to the valves etc.
  • [Deleted User]
    [Deleted User] Posts: 0
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    LP sludge

    I have had this problem before especially with systems using a vaporizor.What I did was put an oil seperator in line with a drip leg at the bottom. If you drain the drip leg every month you shouldnt have a problem anymore. It seems like alot of trouble ,but we just built it into a monthly pm plan for the vaporizor. good luck
  • [Deleted User]
    [Deleted User] Posts: 0
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    LP sludge

    I have had this problem before especially with systems using a vaporizor.What I did was put an oil seperator in line with a drip leg at the bottom. If you drain the drip leg every month you shouldnt have a problem anymore. It seems like alot of trouble ,but we just built it into a monthly pm plan for the vaporizor. good luck
  • Robert O'Connor_12
    Robert O'Connor_12 Member Posts: 728
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    sludge

    I've yet to experience mercaptan residue becoming an issue on a "roof top unit" before. Are you sure thats what it is? More often than not I've found sealant used to pack plug valves to be the culprit. If maintenance personnel don't exercise care in re-packing plug valves properly, they usually blow through the valve and cause problems with fuel trains. Pay special attention when higher pressure gas is used in gas trains utilizing double block & bleed systems. Emergency relief solenoids, regulators as well as high and low pressure switches within the trains can become dangerous when fouled. Another thought would be the source. Has the customer changed suppliers? Maybe, I know its a long shot but possibly the quality of the gas could be, or the residue itself could be checked.


    Robert O'Connor/NJ
  • Eric_25
    Eric_25 Member Posts: 79
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    What type of oil seperator

    are you referring to?
    Do you use one like is normally used in a refrigeration system?

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  • Plumdog_2
    Plumdog_2 Member Posts: 873
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    See it with or without the vaporizer

    but it doesn't occur on all systems; leading one to believe something must be wrong with the LP or the tank or the delivery on non-vaporized setups. The sludge (a black oily substance) must be a form of condensate and seems worse in cold weather conditions when there is a long delivery pipe.
  • Glen
    Glen Member Posts: 855
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    first stage pressure

    should be checked. The 10# outlet pressure is a max pressure - after which the oils and mercaptan do precipitate out. Regardless of vapourizer or just straight reg.
  • Eric_25
    Eric_25 Member Posts: 79
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    two with vaporizer

    We have seen this problem twice, both systems do have a vaporizer.
    Also I will check the setting on the first stage regulator, I have never heard of this being a problem on the first stage reg.

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  • Dave-St Louis
    Dave-St Louis Member Posts: 22
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    Sludge

    Sounds like you are getting the "heavy ends" of the propane.Propane known as HD-5 years ago could contain up to 5% heavy ends, or just plain junk. This might be what you are getting in the gas train and other pipe areas. Many LP vaporizers were piped to supply 10 psig from the first stage PRV and then downstream of the PRV a tee going to the top of the storage tank was installed and another PRV set at 7 or so psig was installed on top of the tank that let the tank vapor feed directly downstream of the main l0 psig PRV. The reason for this was in the event of a vaporizer failure, propane vapor from the tank would start feeding the building load when the line pressure dropped to the 7 psig set point. The tank would then provide propane vapor by natural vaporization. Unfortunately the "good stuff" boiled off first and began leaving behind the "heavy ends". When the vaporizer was put back on line, the "heavy ends" what now are on the bottom of the tank, flow through the vaporizer and end up in the piping system.

    If you want more info on a filter designed for this type of service, you may wish to contact Alternate Energy Systems, Inc. Peachtree City, GA 770-487-8596. Or www.altenergy.com
    Hope this will help.
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