he Dallas Group of America Inc.,a recognized leader in oleo-chem-ical purification technology, is

arguably the only U.S. company activelymarketing a commercial product for theadsorptive purification of biodiesel. Thecompany’s synthetic magnesium silicateadsorbent, sold under the trademarkedname Magnesol, is an “adsorbent filteraid” that ensures biodiesel quality byremoving contaminants within methylesters. Subsequently, the removal of con-taminants enables biodiesel producers toguarantee that the fuel they produce meetsASTM D-6751 specifications and otherindustry standards.

The Dallas Group broke into theNorth American biodiesel market withMagnesol only recently, but according toone producer, the adsorbent could be “acure-all for most process upsets and impu-rity problems” that occur during biodieselproduction. Multiple customers nation-wide in the edible oils industry are alreadyusing the product. Bryan Bertram, direc-tor of industrial sales with The DallasGroup, believes the U.S. biodiesel market

represents one of the next big opportuni-ties for the product line. In an interviewwith Biodiesel Magazine, Bertram, alongwith Chris Abrams, business developmentmanager, and Brian Cooke, product devel-opment specialist, discussed the compa-ny’s ongoing efforts with Magnesol.Bertram said the product increases theoxidative stability of biodiesel and is usedin conjunction with—orin place of—the water-wash treatment in thebiodiesel productionprocess.

After the glycerinseparation process,methyl esters containcontaminant materialsthat are detrimental to the quality of thefuel and must be eliminated from theproduct. Reduction of the water-solublecontaminants, traditionally, is accom-plished by water-washing the biodiesel.However, according to Bertram, the era ofthe biodiesel water-wash may be graduallyending. “The water-wash method doesnothing to remove the water-insoluble

impurities,” he told Biodiesel Magazine.“And due to the resulting effluent water, itgives cause for environmental concerns.”

With Magnesol, the water-wash stepcan be eliminated, and so can the liquidseparation and drying of biodiesel. “It canalso replace other methods of removingchlorophyll, metals, and color frombiodiesel,” Bertram said. “If the processor

is utilizing a costly distil-lation step on the tail endto remove metals orother contaminants, theycould forgo that stepalso. In addition,Magnesol has a highaffinity for methanol andwater, so it will remove

the last bits from methl esters..”Purification with Magnesol also

increases the oxidative stability ofbiodiesel, Bertram said, which is becomingincreasingly important, due to thedemands being placed on fuel producersby the auto manufacturing industry andgovernment.

Magnesol, which can be used in either

What is perhaps mostattractive aboutMagnesol, is that itworks simply and relatively inexpensively.

PROCESS

By Tom Bryan

T

With a solid track record in oleo-chemical purification, The Dallas Group has

entered the biodiesel industry with a synthetic magnesium silicate adsorbent that

has changed the way some producers clean up their methyl esters.

gAdsorbing It All

March 2005 BIODIESEL MAGAZINE 40

PROCESS

batch or continuous processes, removesresidual methanol, providing a cost sav-ings in the stripping step. Magnesol isable to remove sulfur, which is especial-ly important in light of impending U.S.EPA regulations that will limit sulfur indiesel fuel to 15 parts per million.Furthermore, the product significantlyreduces a plant’s need for heated andconditioned water. The traditionallyemployed water-wash method necessi-tates either the purchase of centrifugesor the gravity-separation of the waterfrom biodiesel.

“After transesterification, you havemethyl esters that need purification,”Bertram said, explaining how waterwashing is typically used to remove con-taminants from methyl esters.

Abrams said The Dallas Groupbelieves the water-wash method has sev-eral limitations, including decreasedyields due to methyl ester loss in efflu-ent; high soap levels that cause emulsifi-cation; high effluent treatment and dis-posal costs; and the time and cost ofdrying methyl esters. High soap levels inparticular may lead to poor separation,contribute to yield losses and requiremultiple washes to achieve specification,Abrams said. In some cases, 24 hours arerequired to effect a single separation.

Additionally, it is not uncommonfor producers to end up with a methylester/water emulsion. “Without a water-wash, there are no such emulsionsformed,” Abrams said. “The disposal,and even permitting of, wastewater isdifficult to impossible, depending onplant location. Magnesol greatly reducesdependency on water and resultantwastewater disposal issues.”

What is perhaps most attractiveabout Magnesol, is that it works simplyand relatively inexpensively.

Cooke shared information aboutMagnesol at the 2005 National BiodieselConference & Expo in Ft. Lauderdale,Fla., in early February. His presenta-tion—essentially a detailed explanationof how biodiesel can be purified byusing the company’s trademarked adsor-bent—covered the basic biodieselprocess, the technology of filtration(passive and active), the results of a pilot

Catalyst(NaOH)

+ Methanol

VegetableOils, used

cooking oil,animal fats

TransesterificationContaminated

Methyl Esters

Glycerin

MethanolRemoval

WaterWashing

MethylEsters &Residual

Water

DirtyEffluent

Drying MethylEsters

Biodiesel Production with aWater-wash Treatment

Catalyst(NaOH)

+ Methanol

VegetableOils, used

cooking oil,animal fats

TransesterificationContaminated

Methyl Esters

Glycerin

MethanolRemoval

AdsorbentPurification

FilterCake

MethylEsters

Biodiesel Production with Adsorbent Purification

Animal Feed Fuel Value (Biomass)Compost

41 BIODIESEL MAGAZINE March 2005

PROCESS

plant trial that involved the product, and abrief look at replacing the water-wash stepwith the company’s magnesium silicatetreatment.

Cooke explained that Magnesol couldbe used by biodiesel producers as a “totalreplacement” of the water wash step, or a“polishing step” used to round out thewater wash treatment.

In a standard biodiesel productionprocess, Magnesol—a fine white pow-der—is mixed with unwashed biodiesel ina mixing tank (for five to 10 minutes) afterglycerin separation and after methanolremoval.

According to Cooke, magnesium sili-cate has a strong affinity for polar com-pounds, thereby actively filtering outexcess methanol, free glycerin, mono anddi-glycerides and metal contaminants, inaddition to free fatty acids and soap.These materials are then removed fromthe process through filtration. Note:Glycerin is a polar molecule, and therebysusceptible to the adsorptive abilities ofmagnesium silicate. That’s why Magnesolis added to the process after the glycerinseparation step.

Explaining the difference between“passive filtration” and “active filtration,”Cooke said Magnesol has “charged sites”on its surface (areas that attract the aforementioned unwanted polar compounds).

“Adsorptive sites may have eitheracidic or basic characteristics,” he said,before explaining the testing methodsused to measure the number—andstrength—of adsorptive sites on a givenamount of adsorbent matter such asMagnesol.

Cooke said testing has shown thatsynthetic magnesium silicate has highnumbers of acidic and basic adsorptivesites, as opposed to passive filter-aid-typematerials like diatomaceous earth, which“did not have any active filtration sites.”

With the use of Magnesol, Cookesaid, the producer is left with a potentiallyvaluable “filter cake” rather than dirtyeffluent. Clients of The Dallas Group arecurrently exploring a variety of marketsfor this filter cake, and the companybelieves the byproduct has potential valueas an animal feed supplement, a form ofbiomass fuel, fertilizer or compost.

The BECON study The Dallas Group has over 30 years

experience in the purification of variouschemicals, including esters and the result-ing byproducts of those processes. Inaddition to its own in-house work onbiodiesel (with outside lab confirmation),the Biomass Energy Conversion Facility(BECON) at Iowa State University per-formed trials comparing the traditionalwater-wash method to biodiesel purifica-tion with Magnesol. Results from thisstudy were discussed by Cooke in hispresentation and also by Dr. Jon VanGerpen during a special technology ses-sion at the National Biodiesel Conference.Van Gerpen, a respected authority on thesubject of biodiesel, directed the pilotstudy at the BECON facility. He has sincetaken a position at the University of Idahoas department head of Biological andAgricultural Engineering.

In that study, methyl esters were pro-duced in 40-gallon batches from bothdegummed soybean oil and yellow grease

Filter

FinishedProduct

TankMixTank

Magnesol ®Unwashed biodiesel(after separation and after methanol removal)

Biodiesel Purification Process

Benefits of treatment with

MAGNESOL ®

✔No water-effluent stream

✔No emulsification

✔Improved oxidative stability (OSI)

✔Minimal yield loss

✔Minimal capital expenditure

✔Allows for continuous operation

✔Expedites the purification process

✔Adsorbs residual water

March 2005 BIODIESEL MAGAZINE 42

43 BIODIESEL MAGAZINE March 2005

PROCESS

feedstocks in BECON’s pilot plant reac-tor. In both cases, the methanol wasremoved from the methyl esters, but notinitially water-washed.

First, 20 gallons of the soybeanmethyl esters were water-washed anddried, while another 20 gallons were treat-ed at 77 degrees Celsius with 1-percent-by-weight Magnesol. After 20 minutes of mix-ing (longer than is probably required in acommercial plant setting, Cooke said), thepurified methyl ester was filtered. Theresulting biodiesel from both methodspassed all specifications of ASTM D-6751. According to the study’s authors,Van Gerpen and Kirk Menges, theMagnesol-treated biodiesel contained alower soap and sodium content than thewater-washed and dried sample.Furthermore, the Magnesol-treatedbiodiesel showed a significant improve-ment in oxidative stability when comparedto both the original methyl esters and thewater-washed and dried sample.

In a second trial, 20 gallons of theyellow grease methyl esters were water-washed and dried and 20 gallons weretreated with at 77 degrees Celsius with 2-percent-by-weight Magnesol. After 20minutes of mixing, the purified methylester was filtered. Like the first test withsoy methyl esters, the Magnesol-treatedsample of yellow grease-derived methylesters passed all ASTM specificationswhile the waterwashed and dried sampledid not. The Magnesol-treated biodieselcontained a lower soap and sodium con-tent than the water-washed and dried sam-ple. Again, the Magnesol-treated biodieselshowed a significant improvement inoxidative stability when compared to boththe original methyl esters and the water-washed and dried sample.

During his presentation, Cooke con-cluded that the benefits of treating methylesters with Magensol are multi-fold. Hereiterated Bertram’s claims about theproduct: With Magnesol, there is no watereffluent, no emulsification, improvedoxidative stability, minimal yield loss andminimal capital expenditure, all throughan application that “expedites the purifica-tion process and allows for continuous

operation.”Fielding questions from attendees,

Cooke said the cost of using Magnesol isin the range of 1 cent to 10 cents per gal-lon of finished biodiesel, depending onthe starting contaminant level. However,he reminded attendees that the filter cakecould potentially be used as an animalfeed. “It has a certain nutritional value,” hesaid.

According to Bertram, the capitalcosts of transitioning a biodiesel facility toMagnesol are relatively low. That’s becauseonly a low-tech filtering system is required.In addition to potentially eliminating thedrying step and the requirement for awastewater treatment system, the use ofMagnesol could replace a centrifuge, yield-ing additional savings of capital, time andmaintenance costs.

There are less obvious savings, too,

Bertram said. “Magnesol actually offersthe biodiesel producer a lot of latitude inrunning their process,” he said. “It adsorbsglycerin, free glycerin, metals, soaps,chlorophyll, residual free fatty acids, odors,color, methanol and water. Since Magnesoladsorbs such a wide range of impurities, itcompensates for upstream upsets in theprocess, offering clean and more stablebiodiesel.”

For more information about Magnesol visitwww.dallasgrp.com.

Tom Bryan is editorial director of BiodieselMagazine. Reach him by e-mail attbryan@bbibiofuels.com or by phone at (701)746-8385.

MAGNESOL®

• Guarantee biodiesel quality(ASTM D6751)

• Reduce or eliminate water wash • Eliminate emulsions • Expedite purification process • Reduce energy requirements • Increase process yield • Improve storage stability (OSI)

PHONE 812-283-6675 Ext. 5 EMAIL biodiesel@dallasgrp.com WEB www.dallasgrp.com

PURIFICATIONOF BIODIESELAND OTHER HIGH-PURITY ESTERS

This article was printed in the 2005 March issue ofBiodiesel Magazine.

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