What is Biodiesel Dry Washing?
ABC's Original 3 Ion Exchange
or Dry Wash Towers
The first ion exchange resin
(IER) column was only 6" in
diameter and 48" tall and
designed specifically for the
home biodiesel brewer. Soon
after we built a 10" by 60" and
12" by 72" towers pictured
above.
or Dry Wash Towers
The first ion exchange resin
(IER) column was only 6" in
diameter and 48" tall and
designed specifically for the
home biodiesel brewer. Soon
after we built a 10" by 60" and
12" by 72" towers pictured
above.
How does Biodiesel Dry Washing Work and What is Ion Exchange Resin?
 |  |  |  |  |
What is Ion Exchange Resin?
 |  |  |  |  |
Are there Different Dry Wash Methods/Media?
What are Dry Wash Towers or IER Purification Columns?
Biodiesel was originally made in the chemistry laboratory when scientist discovered, that triglycerides (vegetable oils
and animal fats) when mixed with certain simple alcohols along with a catalyst like sodium hydroxide, produced two
layers of different fluids.
The two layers were so distinct, they were easily separated from one another. The top light colored fluid is what we
call today: BIODIESEL and the dark colored, heavier bottom liquid, is Glycerol.
Although they were easily separated it was noticed that a good deal of contamination remained in the Biodiesel from
the chemical reaction's by-products. These contaminates consisted mostly of soap, glycerin and 'excess' alcohol, that
hadn't been used up in the chemical reaction.
For 50 years biodiesel was produced by this method, however this way of purifying biodiesel requires a relatively large
volume of water amd this water in-turn becomes a contaminate itself and also must be removed. This requires more
time and energy and makes the mass production of biodiesel more challenging and less ecologically viable.
Therefore scientist and biodiesel producers developed new means of purifying the contaminated or crude biodiesel
which didn't require water washing and was therefore dubbed: Dry Washing...
and animal fats) when mixed with certain simple alcohols along with a catalyst like sodium hydroxide, produced two
layers of different fluids.
The two layers were so distinct, they were easily separated from one another. The top light colored fluid is what we
call today: BIODIESEL and the dark colored, heavier bottom liquid, is Glycerol.
Although they were easily separated it was noticed that a good deal of contamination remained in the Biodiesel from
the chemical reaction's by-products. These contaminates consisted mostly of soap, glycerin and 'excess' alcohol, that
hadn't been used up in the chemical reaction.
For 50 years biodiesel was produced by this method, however this way of purifying biodiesel requires a relatively large
volume of water amd this water in-turn becomes a contaminate itself and also must be removed. This requires more
time and energy and makes the mass production of biodiesel more challenging and less ecologically viable.
Therefore scientist and biodiesel producers developed new means of purifying the contaminated or crude biodiesel
which didn't require water washing and was therefore dubbed: Dry Washing...
| Call Greg to discuss your technical questions@ 734.709.8826 Copyright 2009 Arbor BioFuels Company © |
An ion-exchange resin or ion-exchange polymer[1] is an insoluble matrix (or support structure)
normally in the form of small (1-2 mm diameter) beads, usually white or yellowish, fabricated from
an organic polymer substrate.
The material has highly developed structure of pores on the surface of which are sites with easily
trapped and released ions. The trapping of ions takes place only with simultaneous releasing of
other ions; thus the process is called ion-exchange. There are multiple different types of
ion-exchange resin which are fabricated to selectively prefer one or several different types of ions.
Ion-exchange resins are widely used in different separation, purification, and decontamination
processes.
The most common examples are water softening and water purification. Most typical ion-exchange
resins are based on cross linked polystyrene. The required active groups can be introduced after
polymerization, or substituted monomers can be used. For example, the cross-linking is often
achieved by adding 0.5-25% of divinyl-benzene to styrene at the polymerization process.
Non-crosslinked polymers are used only rarely because they are less stable. Cross linking
decreases ion- exchange capacity of the resin and prolongs the time needed to accomplish the ion
exchange processes.
normally in the form of small (1-2 mm diameter) beads, usually white or yellowish, fabricated from
an organic polymer substrate.
The material has highly developed structure of pores on the surface of which are sites with easily
trapped and released ions. The trapping of ions takes place only with simultaneous releasing of
other ions; thus the process is called ion-exchange. There are multiple different types of
ion-exchange resin which are fabricated to selectively prefer one or several different types of ions.
Ion-exchange resins are widely used in different separation, purification, and decontamination
processes.
The most common examples are water softening and water purification. Most typical ion-exchange
resins are based on cross linked polystyrene. The required active groups can be introduced after
polymerization, or substituted monomers can be used. For example, the cross-linking is often
achieved by adding 0.5-25% of divinyl-benzene to styrene at the polymerization process.
Non-crosslinked polymers are used only rarely because they are less stable. Cross linking
decreases ion- exchange capacity of the resin and prolongs the time needed to accomplish the ion
exchange processes.
Ion exchange is a chemical reaction wherein an ion from solution is exchanged for a similarly charged
ion attached to an immobile solid particle (i.e., ion exchange resin). Ion exchange reactions are
stoichiometric (i.e., predictable based on chemical relationships) and reversible. The resins are
normally contained in vessels referred to as columns. Solutions are passed through the columns and
the exchange occurs. Subsequently, when the capacity of the resins is reached, the ions of interest,
which are attached to the resin, are removed during a regeneration step where a strong solution
containing the ions originally attached to the resin is passed over the bed.
The strategy employed in using this technology is to exchange somewhat harmless ions (e.g.,
hydrogen and hydroxyl ions), located on the resin, for ions of interest in the solution (e.g., copper). In the
most basic sense, ion exchange materials are classified as either cationic or anionic. Cation resins
exchange hydrogen ions for positively charged ions such as copper, nickel, and sodium. Anion resins
exchange hydroxyl ions for negatively charged ions such as sulfates, chromates, and cyanide.
The basic ion exchange column consists of a resin bed which is retained in the column with inlet and
outlet screens, and service and regeneration flow distributors. Piping and valves are required to direct
flow and instrumentation is required to control regeneration timing. The systems are typically operated
in cycles consisting of the following steps (ref. 3):
1. Service (exhaustion) – Water solution containing ions is passed through the ion exchange
column or bed until the exchange sites are exhausted.
2. Backwash – The bed is washed (generally with water) in the reverse direction of the service cycle
in order to expand and resettle the resin bed.
3. Regeneration – The exchanger is regenerated by passing a concentrated solution of the ion
originally associated with it through the resin bed; usually a strong mineral acid or base.
4. Rinse – Excess regenerant is removed from the exchanger; usually by passing water through it.
The ion exchange process has been commercially available for many years, but early use was primarily
for water deionization or softening.Widespread interest in the process for Biodiesel Purification is a
more recent application that has grown rapidly over the past 2 years
years.
ion attached to an immobile solid particle (i.e., ion exchange resin). Ion exchange reactions are
stoichiometric (i.e., predictable based on chemical relationships) and reversible. The resins are
normally contained in vessels referred to as columns. Solutions are passed through the columns and
the exchange occurs. Subsequently, when the capacity of the resins is reached, the ions of interest,
which are attached to the resin, are removed during a regeneration step where a strong solution
containing the ions originally attached to the resin is passed over the bed.
The strategy employed in using this technology is to exchange somewhat harmless ions (e.g.,
hydrogen and hydroxyl ions), located on the resin, for ions of interest in the solution (e.g., copper). In the
most basic sense, ion exchange materials are classified as either cationic or anionic. Cation resins
exchange hydrogen ions for positively charged ions such as copper, nickel, and sodium. Anion resins
exchange hydroxyl ions for negatively charged ions such as sulfates, chromates, and cyanide.
The basic ion exchange column consists of a resin bed which is retained in the column with inlet and
outlet screens, and service and regeneration flow distributors. Piping and valves are required to direct
flow and instrumentation is required to control regeneration timing. The systems are typically operated
in cycles consisting of the following steps (ref. 3):
1. Service (exhaustion) – Water solution containing ions is passed through the ion exchange
column or bed until the exchange sites are exhausted.
2. Backwash – The bed is washed (generally with water) in the reverse direction of the service cycle
in order to expand and resettle the resin bed.
3. Regeneration – The exchanger is regenerated by passing a concentrated solution of the ion
originally associated with it through the resin bed; usually a strong mineral acid or base.
4. Rinse – Excess regenerant is removed from the exchanger; usually by passing water through it.
The ion exchange process has been commercially available for many years, but early use was primarily
for water deionization or softening.Widespread interest in the process for Biodiesel Purification is a
more recent application that has grown rapidly over the past 2 years
years.
Magnesium Silicate powder was one of the very first "dry wash" medias but unfortunately Magnesium Silicate had 3 disadvantages:
1) It was highly consumable and therefore required ongoing purchases and need to be disposed of which also incurred expenses
2) It required a significant amount of resources for removal and change-out in a production system which incurred even more cost
3) The grains of powder had a very large variance in size with some particles being less than 1 micron making them exceedingly difficult to
remove and this caused an abrasive contaminated fuel
As an alternative to powders for capturing these polar molecular contaminates some one stumbled on the idea of artificial polymer beads -
ION EXCHANGE RESIN (IER). These Ion Exchange Resins seemed to solve all these problems because they had very definitive particle
sizes (beads), that were easily contained in fixed resin beds. They were reusable and therefore didn't require ongoing expenditures for
more material and maintenance. Even more appealing was that different resins could be counted on to perform different functions and so
could be tailored to any one particular process.
These two materials sparked a large amount of research and trial, which are looking at other types of biodiesel purifying medias.
The key here being medias which are inexpensive, common, reusable and ecologically friendly. Some examples have been: Gypsum,
Wood fiber and Peet Moss.
Jon Van Gerpen of Idaho State University took on studying the different "Dry Wash" medias and concluded that when considering
all the cost involved Ion Exchange Resins proved to be the most economical means of purifying BIODIESEL...
1) It was highly consumable and therefore required ongoing purchases and need to be disposed of which also incurred expenses
2) It required a significant amount of resources for removal and change-out in a production system which incurred even more cost
3) The grains of powder had a very large variance in size with some particles being less than 1 micron making them exceedingly difficult to
remove and this caused an abrasive contaminated fuel
As an alternative to powders for capturing these polar molecular contaminates some one stumbled on the idea of artificial polymer beads -
ION EXCHANGE RESIN (IER). These Ion Exchange Resins seemed to solve all these problems because they had very definitive particle
sizes (beads), that were easily contained in fixed resin beds. They were reusable and therefore didn't require ongoing expenditures for
more material and maintenance. Even more appealing was that different resins could be counted on to perform different functions and so
could be tailored to any one particular process.
These two materials sparked a large amount of research and trial, which are looking at other types of biodiesel purifying medias.
The key here being medias which are inexpensive, common, reusable and ecologically friendly. Some examples have been: Gypsum,
Wood fiber and Peet Moss.
Jon Van Gerpen of Idaho State University took on studying the different "Dry Wash" medias and concluded that when considering
all the cost involved Ion Exchange Resins proved to be the most economical means of purifying BIODIESEL...
