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Grounding and Bonding and Static electricity

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February 08, 2018, 01:46 PM
Grounding and Bonding and Static electricity
I was concerned that in making biodiesel there might be static spark ignition of diesel/methanol vapor while transferring to settle tanks after demething at 90C which is above diesels flashpoint.

Once all other sources of ignition are resolved: open flame, dry firing a processor, electrical sparks from switches and unplugging extension cords, removing vapors with good ventilation and stupidity there is static charge/electricity.
Many sources describe how fluids in movement and agitation (read as pumping, bubbling, free fall splashing into a drum, spraying and filtering) can generate a static charge
Any fluid with greater than 50pS/m “conductivity” is NOT considered a static accumulator. Biodiesel has a conductivity of around 406pS/m (UNLIKE the new petro ULSD now being produced which is often < 10pS/m !) Methanol is 150,000 to 2,000,000pS/m.
Luckily for our situation methanol and biodiesel have good “conductivity” (unlike gasoline and petro diesel) and will not be “charge accumulators” IF they are provided a bonded connection to ground. But they may still generate a charge in the above agitations.

Those details are in the article posted by John H.

Since some of us (me) demeth up to 90C it poses a risk during transfer to settling tanks after being churned in the demething process and then the hot biodiesel piped or sprayed, maybe through a non-conductive vinyl hose, into an open plastic barrel to further demeth, even outside with a large fan blowing . And also a risk when mixing Methanol and Lye and churning in a plastic drum.

The suggestions made for regular fuels were:
1. Keep flow rates at or less than 3 gpm when transferring (to less likely generate a static charge) and this nicely fits a Northern Tools blue pump rate.
2. Bond plastic barrels with dip wires/rods to the bottom of the fluid and from there to a bonded and grounded processor or filling from the bottom up.
3. Lots of ventilation if transferring into an open top barrel (to keep the vapor too lean to ignite)
4. Leave transfer nozzle in contact with fluid in the receiving barrel after transfer has stopped to allow the charge to “relax”
5. Ground yourself/clothing before touching near any transfer point by touching another part of the processor first
6. Ground system must be 10 ohms resistance or less
And my new changes
1. demeth finished biodiesel under vacuum to reach a transfer temp below 60C.
2. don’t spray into open top plastic settle drum to get that last amount of methanol out but rather into a closed drum with a long ventilation pipe going “somewhere else”, like not next to the smokers section.
3. Jumper cable connect my methoxy drum with its copper dip tube to the processor before infusion (? Is this overkill?)

So, a few bonding wires and dip wire/rods and a check on how well grounded our processors are? Is this what you experienced producers do, tie it all together? Is this somewhere in the original beginners Appleseed design project?

This message has been edited. Last edited by: sooty,