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Burning propane and natural gas in same burner train

Gene_3
Gene_3 Member Posts: 289
in THE MAIN WALL
you like living dangerously

Comments

  • Nicolle
    Nicolle Member Posts: 4
    Propane/natural gas

    Have you ever seen a boiler burn both propane and natural gas without making any changes to the burner train?
  • Charles G.
    Charles G. Member Posts: 113
    Propane/nat

    Short answer--no. Propane and nat gas run @ different pressures; usually 11' w.c. for propane and 3.5-5" for n.g. Propane burner orifices are smaller than n.g. orifices to compensate for the difference. Wrong orifice/wrong gas and you'll either be WAY overfired or barely able to light the burners. Pressure regulator springs are also different. No, you can't use a propane tank to fire your heating system when you forget to pay your gas bill...
  • Bob D._2
    Bob D._2 Member Posts: 34
    LPG/NG Gas Train

    Well, kind of. (Oh boy am I going to regret this . . .) In larger plants, where an Interruptible Gas rate is desireable or necessary, LPG can be used as a back-up fuel in a NG burner without changing the gas train significantly by incorporating a LPG vaporizer (heater) and (air) mixer, which gets the propane to the correct pressure and higher heating value to approximate natural gas. As far as the burner and gas train knows, nothing has changed (service pressure, BTU/cu ft, etc.) so all the safeties and combustion controls keep the same characterised values as for natural gas. This tends to get pretty expensive, and can be a PIA to maintain correctly. It's usually easier and less expensive to just go dual fuel NG/#2 FO.
  • Charles G.
    Charles G. Member Posts: 113
    Gas train

    So can I get one at my house?
  • marc friedman
    marc friedman Member Posts: 35


    sure ..

    i sell Eclipse
    your cost for a vastly oversixed unit is around $25,000
  • jeff_25
    jeff_25 Member Posts: 110
    burner

    i think it was the propane to nat gas that blow up at faulk corp. in milwaukee wisconsin
  • Plumdog_2
    Plumdog_2 Member Posts: 870
    Seen it Done

    In a High School; no less. But the LP tank and Vaporizer were gone before I worked on it. It could be done but it would be difficult and expensive for a residential application. The system I saw had two gas trains piped into the same manifold with manual switchover valving.
  • Glen
    Glen Member Posts: 854
    two methods of doing this

    But only one could use the same gas train - and that is the LPG/air mix method. And I have only seen those on mills and dryers - that eat up millions of btus/hr. For smaller commerical applications - a duel fuel gas train is needed. I have never seen one for residential (sfd) use. Pic attached is from a hospital - nat gas main - w ith LPG backup. In case of Nat gas failure (gas line break) - the propane company has gauranteed 4 hour service - to roll up a large tanker/vapourizer and keep the heat on.
  • Nicolle
    Nicolle Member Posts: 4
    Propane/natural gas

    Well after much research and posting the message to the Wall yesterday - I have found out that they are using the vaporizer air mix method to make what they call synthetic Natural Gas with the same characteristics of real Natural Gas. It is happening at a local college where they are going away from the central heating plant and putting individual boilers in the buildings. They run on natural gas and than the "synthetic" Natural Gas (propane mix) will be the backup for the dual fuel. I guess the gas is easier to pipe everywhere rather than having fuel oil as the backup and having a tank at each location as well. Thanks for everyone's help on this topic - I have learned a lot!
  • Barbarossa
    Barbarossa Member Posts: 89
    LPG/ Nat

    Basically it is done all the time but due to the costs of the equipment to blend the gas it would be a nonstarter for a house sized load. The propane or other LPG is blended so it behaves as Natural gas: albeit it has a higher heat value but the real issue is other aspects of the existing equipment better have 100% shut off because it still retains the heaver then air and explosive qualities of LPG. For further information you can look up Wobbe Index on the internet as that will explain the physics’ underlying the process. I am too bad at what I do and I live in a remote area; But, I would not consider blending at my house under any conditions.
  • Phil Burkhart
    Phil Burkhart Member Posts: 6
    Raypak

    Raypak has FlexGas Dual Fuel units from 300 MBH to 2340 MBH.
    It will switch from natural gas to propane with the turn of a key.
This discussion has been closed.

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