Biodiesel Dry Wash Systems

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If you've heard about the 'Dry Wash' method of cleaning your Biodiesel, but are not sure what it is, or how it works, this section will tell you all about it. You will be amazed at how simple this process is, and how much time it will save you. With no water washing at all your Biodiesel will come out sparkling clean and shiny looking. You can now cut your hands on time In Half! With the proper procedures this system is capable of outputting ASTM grade Biodiesel in one pass through the system. Here, we will specifically discuss the Thermax T45 BD Macro Resin as that is the one we will offer to our customers due its superior cleaning abilities.

What is Dry Washing?

When we talk about Dry Washing our Biodiesel we are referring to a revolutionary process by which we eliminate all need for water washing to clean our fuel and instead clean our fuel in one pass using a Dry Wash media. This saves the tedious steps of water washing and drying the fuel, and still results in premium quality, clean Biodiesel. This kind of media has been specially designed by manufacturers such as Purolite, Rohm & Haas, Dow or the newest media, Thermax T45. The way it works is that you process the Biodiesel as you normally would; draining the glycerin off completely, then you pass the Biodiesel through a Dry Wash Resin tower. As it passes through the tower the resin will clean the Biodiesel via an "Ion Exchange" process, similar to the way a water softener works. Nothing is added to the fuel like with Magnesol, but all the contaminants are removed leaving you with pure, clean Biodiesel.

How it works

In a nutshell you simply pass the raw Biodiesel through the dry wash system slowly, and out comes sparkling clear, ready to run Biodiesel! It only takes One Pass through the column with this system! You will be amazed. The simple technical explanation is that as the Biodiesel passes through the resin, the Ion Exchange process takes place whereby an atom of hydrogen is strongly attracted to the contaminants in the Biodiesel, but not the Biodiesel itself. This strong attraction usually results in an atom of hydrogen being replaced (exchanged) with an atom of a contaminant. The contaminant is now attached to the resin in place of the hydrogen and the hydrogen molecule is left in the Biodiesel. This all happens on a molecular basis and is a very efficient method of cleaning the fuel.

More about the Thermax Resin

Thermax resin was specifically created to clean higher viscosity liquids through an Ion Exchange method. First, the resin is created in the factory and is specifically made to be very porous, which increases the available cleaning surfaces by having internal and external surfaces. You could picture the resin looking similar to a sponge, but on a microscopic scale. After the resin is created, it is then treated with Hydrogen from Sulphuric Acid. They do this by soaking the resin beads in a bath of highly concentrated Sulphuric Acid which causes millions of the Sulphuric Acid's molecules to actually bond to the surfaces of the resin beads. This leaves behind millions of molecules of hydrogen attached to the surfaces of the resin, ready for cleaning.

Design Considerations

In order for this process to thoroughly clean the fuel there are several design and operating principles that must be adhered to. If we ignore these or do them improperly we will end up with fuel that is not thoroughly cleaned or purified and could cause damage to our engines. First of all the vessel must be designed properly to be durable and to allow the proper flow rate, filtration, etc. The dry wash system we now offer is in a sturdy steel column which is needed due to the expansion of the media when it is soaked with Biodiesel. Depending on the media it can expand from 50-100% once saturated. Fiberglass and PVC columns can crack due to this expansion, so we now only offer the steel columns. The column also has to have the correct aspect ratio to achieve the proper flow rates and contact area. When we pass the Biodiesel through the Thermax resin we are attempting to do several things. We are trying to get the Biodiesel to pass through the resin equally, so that all the surfaces of the resin get to clean the fuel equally, avoiding loading up parts of the resin while others remain clean. And we are ensuring the Biodiesel has plenty of time to pass through the resin, allowing the resin the time it needs to completely remove the contaminants.

Quality

Just take a look at the quality of the welds as shown in the photo on the right. These are built very well for many years of service. They are not manufactured by an amateur welder in their garage.

Screens have been an issue in some systems, but not with our new systems. The screen is supported by a sturdy steel support plate and should last indefinitely.

(click image for larger view)

The Thermax resin beads are an improvement over the Purolite and Amberlite primarily due to the larger internal pores. The Thermax resins used in this process are considered to be Macro Porous resins vs micro porous for the other resins. Purolite and Amberlite resins have pores designed to let water pass through them but due to Biodiesel's higher viscosity, it is not able to pass through these resins. Thermax pores are Macro Porous meaning the pores are much larger, which allows the more viscous Biodiesel to flow through the pores and not just over the surface which greatly increases its cleaning ability. The Thermax resin is also less susceptible to compaction and pressure build ups due to bead swelling compared to Purolite and Amberlite. You can also expect the Thermax to last longer before needing cleaned due to the macro porous resin having more useable surface area. Thermax resin also exhibits a noticeable reduction in the formation of a gelatinous fouling layer which can form on the top of resin beds under use.

Technical note: in the business they don’t actually use the term “microporous”, I have chose to describe it this way since “non-porous semi-permeable” doesn’t translate as well when trying to explain the advantages of a Macro-porous resin. The reason I say this is because gel-resin are considered Non-porous by professionals!

Methanol Removal

Before beginning the dry washing we must first remove the remaining un-reacted Methanol as it can cause problems with the dry wash if we don't. The remaining methanol can cause more contaminants to stay suspended in the Biodiesel causing you to deplete the cleaning capacity of the resin soon.

Here are a few methods for removal of the methanol from the processed Biodiesel.
" Incorporate the 5% water pre-wash (Instructions included with your system or available on our processor customer only website)
" Using something like an aquarium bubbler, bubble air up through the Biodiesel for several hours. This will evaporate the methanol and allow it to be vented out the methanol vent line of your processor.
" If you are unable to use either of these methods you can use a centrifuge, or just settle the Biodiesel for as long as possible. Several days will not hurt. Drain the glycerin each day to ensure you get as much out as possible and the methanol content should be reduced.

Q - Will the Thermax resin remove Glycerin?
A - Yes, it will, but you want to avoid this or you'll deplete your resin prematurely. Be sure to settle for as long as possible and drain the glycerin completely to avoid this problem.

Q - Will the thermax resin remove Methanol?
A - A Dry wash system will remove only trace amounts of methanol, however you want to remove the methanol first by other means as this is not the intended function of the dry wash media.

Q - Can dry washing completely replace Water Washing?
A - Yes, if you follow the recommendations given. But keep in mind that water washing removes Glycerin, soaps, catalyst, methanol and other impurities, in a multi stage process. The dry wash method is intended to only to remove the remaining glycerin after thorough draining and removal prior to dry washing, along with metals, soaps and some other contaminants, but it is not recommended to remove the methanol or large amounts of glycerin.

Q - How much does this add to the cost of making Biodiesel?
A - That answer varies, but if you replace the media each time it is depleted the added cost is approximately 10 cents per gallon. This works out like this: 20 lbs of Thermax will clean roughly 2000 gallons of fuel and the 20 lbs costs $180.00 plus $25.00 shipping. So it costs roughly $200.00 to make 2000 gallons of fuel, or 10 cents a gallon.

Q - How long does the media last?
A - When used properly you will be able to process roughly 100 gallons of fuel for each pound of media. Therefore 20 lbs would process 2000 gallons of fuel, although you may be able to process much more if you are careful. The media itself can be replaced each time it is depleted, or you can clean it with methanol, and then re-use the methanol for the next batch.

Q - What flow rates are recommended?
A - This is an important item so don't ignore this section. Flow rates are recommended as follows:
" Model EZDW-6a, 6" tower - 9 gallons per hour or .15 gpm
" Model EZDW-10a, 10" tower - 25 gallons per hour or .42 gpm
" Model EZDW -12a, 12" tower - 50 gallons per hour or .83 gpm

Q - What kind of pump do I need?
A - We can supply a bypass assembly that will work on most processors by allowing you to bypass roughly 99% of the flow coming out of your processors pump while sending only the recommended amount through the dry wash system. This bypass will work on most any pump saving you the cost of an additional pump. Or we can help you get a pump with an adjustable flow allowing you to pump exactly the right amount. Contact us for details.

Q - What is the operating temperature range for the Thermax resins?
A - The maximum temperature is 70°C (158°F). Recommended operating temperature is 30 - 40º C (86 - 104°F).

Q - What is the storage criteria for the resin when not in the columns?
A - Avoid overheating or freezing conditions. Products should be stored in the original containers, with the internal polyethylene liner folded over the product in order to minimize the chance of absorption of water vapor from the air. Normal storage temperatures would vary from 40°F to a maximum of 110°F. Shelf-life for most ion exchange resins and adsorbents is 5-years but for dried resins, moisture level should be checked after 2-years to ensure the moisture content has not increased appreciably.

Q - What is a Lead Lag system?
A - A lead lag system is simply a way of ensuring the highest quality fuel output all the time, with less down time and is primarily used by commercial producers. The way it works is the first column removes the majority of the contaminants but at some point it will begin to lose its capacity for one or more of the impurities. At this point some of the contaminants will begin getting by the media in this first tank, a point called 'Break Over'. But with a second dry wash column the second column will catch anything that gets past the second during this break over point. So the second tank is basically a backup tank. And once the first tank reaches the break over point the tanks can be switched with the second tank now acting as the primary filter. For the best cleaning, you would want to replace the media in the first tank before implementing it as the lag tank. A lead lag setup is not really necessary for most of us but the option is available if you wish.

Q - How big a system do I need?
A - A good recommendation is to figure out how many gallons a year you make and purchase a system that will process that amount. That way you are only changing the media out once a year. Or here's the general guidelines -

A - No, you can do fine with one column if you don't try to push your media beyond it's useable life. See the Lead Lag question above for more info.

A - The dry wash resin beads may be safely landfilled once any methanol is removed. Just dry them out and landfill them.


	Dry Wash Systems

Biodiesel dry wash system with Thermax or Purolite resin


	Descriptions

Model EZDW-6a

6" Column

Our 6" column is perfect for most small EZbiodiesel users and comes with 20lbs of Thermax Resin. Cleans at least 2000 gallons of biodiesel when processed properly. Media is loaded and unloaded via the top bolted on plate.

Ideal for those who process up to 80 gallons per week.

Specifications - 6" diameter, 60" high with stand. Media Capacity - 20lbs max. Material - steel. 3/4" inlet/outlet. Flow rate - 9 gallons per hour or .15 gpm. Media life - at least 2000 -3000 gallons OR More

Model EZDW-10a

10" Column

Our 10" column is perfect for slightly larger EZbiodiesel users and comes with 70lbs of Thermax Resin. Cleans at least 7000 gallons of biodiesel when processed properly. Media is loaded and unloaded via the top bolted on plate.

Ideal for those who process up to 200 gallons per week.

Specifications - 10" diameter, 72" high with stand. Media Capacity - 70lbs max. Material - steel. 3/4" inlet/outlet. Flow rate - 25 gallons per hour or .42 gpm. Media life at least 7000 - 10,000 gallons OR More

Model EZDW-12a

12" Column with bottom drain plate

Our larger 12" column is perfect for EZbiodiesel users producing higher volumes and comes with 120lbs of Thermax Resin. Cleans at least 12000 gallons of biodiesel when processed properly. Media is loaded through the top flange but is unloaded via the bottom plate on this model.

Ideal for those who process up to 300 gallons per week.

Available in Top flow (top to bottom) and bottom flow (bottom to top, costs extra)

Specifications - 12" diameter, 85" high with stand. Media Capacity - 120lbs max. Material - steel. 3/4" inlet/outlet. Flow rate - 50 gallons per hour or .83 gpm. Media life at least 12000 - 18,000 gallons OR More

EZDrain plate on bottom of model EZDW-12a column

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Top of model EZDW-12a column

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To contact us via email, please click the link to the right - EZBiodiesel Support

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