4 replies to this topic

[DAIALOS]

Hello Everyone

 

I am currently working in an Ethanol plant. Right now I am performing a project focused on reduces the quantity of evaporation of the product.  We believe that we are losing volume by evaporation when we fill the car trucks because of the “Splash Effect” when filling them from the top. 

Is there any way I can actually get an estimate of how much volume we could be losing from evaporation when filling those car trucks? Is there any way to calculate that quantity or maybe performing a Test or something?

 

Thanks

[Art Montemayor]

 

Daialos:

 

You bring up a problem that is of concern in most ethanol plants I’ve been involved in in the past.  The vapor pressure of ethanol at tropical temperatures is the first concern that comes up – followed by the filling losses that are experienced.  I know of no method to estimate the potential loses of ethanol due to turbulence and heat pick-up in the truck filling process but the way that we used to fight that loss potential was to install a vapor balance type of truck filling.  We decided to fill all trucks through a dip pipe on a quick-connect flanged nozzle connection.  That way there was no splashing (except at the initial outset).  The vapor(s) generated (especially by the empty tank trucks that come in for filling after being exposed to the hot, tropical sun (at about 120 – 130 ^oF) are handled by the vapor balance line that is connected to the ethanol storage fill tank vapor space.  This method ensures that there are no flammable, emission vapors are going to the atmosphere.  If generated, they simply are routed back to the storage tank vapor space (which should be cooler than the tank trucks).

 

The filling procedure is slower; it takes two tank truck connections instead of just one – but it eliminates all emissions.  This is not only justifiable from a loss prevention point of view, but also from a safety and environmental argument as well.  The additional cost of the vapor balance hose connection should be minimal capital involved.  The almost hermetic type of filling should be welcomed by the filling crew manning the filling station.  Exposure to ethanol vapors for one shift can cause headaches and other health problems. - plus the flammability potential.

 

[DAIALOS]

Mr. Montemayor

 

Thanks for always help providing such excellent information.  I am not really informed about what is a “Vapor Balance system for car Trucks filling”, is there any place where I can find more information about this type of systems?  Just for me to be clear, the deep tube that u mention I suppose is a mechanism that will be submerged in the fluid so the splash is totally eliminated?

 

Again, Thanks!

[Art Montemayor]

Daialos:

 

Please refer to the attached quick and very basic sketch.

 

A vapor balance type of liquid transfer is a universal system used when dealing with toxic, flammable, or expensive vapors related to the transferred liquid.  It allows you to transfer the liquid fluid as fast as you want without any problems of trapped vapor or pulling a vacuum in your source tank.  It essentially replaces the pumped out liquid in the source tank with the vapor in the target tank.  Both the target and source tanks are kept at the same pressure.  Many compressed liquids – such as ammonia, carbon dioxide, LPG, and others are transferred in this manner every day.  I’ve even transferred liquid phenol with this system.  As with everything else, you should expect a tradeoff for eliminating all emitted ethanol vapors.  For example:

• You will have to standardize all your tanker trucks transporting your ethanol out of your plant to be equipped with a standard filling dip pipe that suits your established filling system.  This is something I’ve found to be not a problem when discussed with your transporter, who should be happy to eliminate all dangerous vapor fumes while exposed to filling.  If you own your transport tankers, then this is even easier to arrange.
• You will need to install a vapor line on your storage tank(s).  If you are filling from various tanks, then this calls for a vapor balance header with block valves on each tank.  If you have a common pressure establish on all your storage tanks, then this is even easier.
• I don’t know how you presently meter your ethanol filling operation.  I presume you are weighing your vehicles while filling.  If so, you should have no problems with this system.  If you are using a visual check while filling, the method will require you to have level detectors.  This is a problem where operations are run on a very low cost level and the operation is manual.  This type of old fashioned operation does not allow for vapor emissions control and has to be modernized in any event if current regulations on emissions, safety, and costs are to be implemented.

I don’t have any basic data on your installation so that’s all I can furnish.  I hope this helps you out.

 

 Ethanol Tank Truck Filling.xlsx   17.16KB   41 downloads

[DAIALOS]

Thank you so much

 

Excellent Information