Fluid Velocity and Static Charge
Fluid Velocity and Static Charge
(OP)
Hi,
We have an ethanol plant that we are working on starting back up. When we are loading a barge, we will be pumping out at 3000 GPM. A large pump is pumping the denatured ethanol through an 18 inch pipe that is reduced to 6 inches and then is run through a coriolis mass meter and a 6 inch on/off butterfly valve and then through a hose out to the barge. The reduction was put in to save money on the coriolis meter. I can't say that this makes a lot of sense in the long term because you'll have to spend more money on a bigger pump and extra electricity for the pump. My basic question revolve around if it will work.
I don't think static charge will be an issue since ethanol is more conductive than 50 pS/M (API Protection Against Ignitions Arising Out of Static, Lighting, and Stray Currents).
I don't think cavitation will be an issue since the downstream pressure is 9 PSI and this is about the 2.5-3 PSI denatured ethanol vapor pressure.
The flow velocities through the pipe are 3.73 fps in the 18 inch section and 33.16 fps in the 6 inch portion. What will this do to the pipe? What will it do to the 6 inch butterfly valve?
We have an ethanol plant that we are working on starting back up. When we are loading a barge, we will be pumping out at 3000 GPM. A large pump is pumping the denatured ethanol through an 18 inch pipe that is reduced to 6 inches and then is run through a coriolis mass meter and a 6 inch on/off butterfly valve and then through a hose out to the barge. The reduction was put in to save money on the coriolis meter. I can't say that this makes a lot of sense in the long term because you'll have to spend more money on a bigger pump and extra electricity for the pump. My basic question revolve around if it will work.
I don't think static charge will be an issue since ethanol is more conductive than 50 pS/M (API Protection Against Ignitions Arising Out of Static, Lighting, and Stray Currents).
I don't think cavitation will be an issue since the downstream pressure is 9 PSI and this is about the 2.5-3 PSI denatured ethanol vapor pressure.
The flow velocities through the pipe are 3.73 fps in the 18 inch section and 33.16 fps in the 6 inch portion. What will this do to the pipe? What will it do to the 6 inch butterfly valve?





RE: Fluid Velocity and Static Charge
RE: Fluid Velocity and Static Charge
An example of charge build-up while transferring ethanol can be found in Crown and Louvar's Chemical Process Safety: Fundamentals with applications, Prentice Hall.
RE: Fluid Velocity and Static Charge
Hacksaw, it is kind of a messed up project. The owners want to get the plant running with as little money as possible. If all goes as plan, they'll be in the black after one full year of operation. The owners are junk dealers who bought the plant for scrap. They decided to try to restart the plant instead when they saw how much money there's in ethanol.
RE: Fluid Velocity and Static Charge
the 10 fps rule is to reduce volitization and static build up in the tank. the brewer doesn't refer to ethanol as a hydrocarbon, but the fire marshall does, and it is just as hazardous as can be when something goes wrong. at 33 fps something already has...
how long do you want the valve to function?
RE: Fluid Velocity and Static Charge
RE: Fluid Velocity and Static Charge
http://virtualpipeline.spaces.msn.com
RE: Fluid Velocity and Static Charge
my guess is that the valve is toast in the design stage.
at a minimum the actuator is not sized for that service, and will not allow stroking,if the valve shaft (depends on the design) or the shaft bearing survives start up. Should failure occur the disk will pass merrily downstream and the shaft generally is projected into the area depending on the service pressure.
A call to the valve manufacturer to check actuator requirements might be a good place to start.
RE: Fluid Velocity and Static Charge