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GreenField Ethanol Successfully Trials Membrane Dewatering Technology; Potential for 40% Savings in Energy Costs

The Vaperma Siftek dewatering membrane modules in the ethanol production process. Click to enlarge. Source: Vaperma

GreenField Ethanol, Canada’s largest ethanol producer, completed a successful trial demonstration of a new membrane dewatering technology from Vaperma that can significantly improve the efficiency of the ethanol production process.

Use of the Vaperma Siftek membrane eliminates the distillation and molecular sieve units typically in place in an ethanol plant. By replacing these, GreenField could save up to 40% in energy costs.

GreenField President and CEO Robert Gallant announced the results of the demonstration at the inauguration of Vaperma Inc.’s 22,000 square-foot research and technology centre for the development and pilot testing of gas separation membranes in Saint-Romuald, Québec.

The pilot dewatering membrane process is scheduled to go into production in the fall of 2007 with a production capacity of 20 m3 per day—the equivalent of about 6% of Greenfield’s Chatham fuel ethanol plant production, according to Gallant.

A Vaperma Siftek membrane module consists of thousands of polymeric hollow fibers—extruded using a wet/dry-phase—embedded into a thermoset resin that is permanently bonded to a fixture ring seal to form a removable cartridge. The cartridge is inserted into a pressure vessel made of carbon steel, stainless steel, or ABS plastic, depending upon the application.

The Vaperma Siftek membrane works with any water-vapor gas blend. Source: Vaperma

The membrane works with any water-vapor gas blend. Each fiber consists of two layers with different properties: an inner, active layer where separation occurs, and an outer porous sublayer that provides mechanical support and draws the water vapor out. Both layers together are no more than 0.2mm thick.

When a wet, pressurized gas comes into contact with the membrane, water molecules readily move into the hydrophilic active layer. Water vapor diffuses across the boundary, and is drawn out of the outer layer.

In ethanol production, the ethanol-water mixture resulting after evaporation has a 40:60 ethanol to water vapor content. This blend flows into a first Siftek module, where 90% of the water vapor is removed, pumped out and condensed, and sent back for re-use in production. The remaining gas flows to a second series of modules, where the remaining water is removed, resulting in the 99+% fuel-grade ethanol.

Water vapor is carried away in the permeate stream at low pressure. The separation unit typically operates under a total pressure of 1 to 1.5 bar within the capillary tubes and a vacuum outside of the membranes.

Vaperma attributes the higher selectivity and permeance of water compared to ethanol are attributed to the unique polymer formulation and the membrane fabrication process.

GreenField Ethanol began discussions with Vaperma two years ago about installing a demonstration project at its Tiverton, Ontario ethanol plant. This project proved to be the first large-scale demonstration in North America of membrane technology for the dewatering of ethanol.

Researchers in Japan are among those who are also exploring the use of membrane technology for dewatering ethanol. (Earlier post).

GreenField Ethanol, formerly Commercial Alcohols, is Canada’s leading ethanol producer. The company produces 250 million liters (66 million gallons US) a year of corn-based fuel ethanol at its plants in Chatham and Tiverton, Ontario and Varennes, Québec. Two more plants are under construction in Hensall and Johnstown, Ontario, and will be operational in 2008. GreenField Ethanol will be one of the top producers in North America with five operating plants, producing more than 700 million liters (185 million gallons US) of ethanol per year by 2008. GreenField’s Ethanol is available at more than 1,500 gas stations across Canada.

(A hat-tip to John!)


Excellent development.

What are the total energy and water savings (and extra cost if any) per litre or gallon produced?

What will be the net effect on ethanol production cost?


Encouraging news. This illustrates a point that I repeatedly try to call out to the endless supply of ethanol naysayers on this site, who seem to base all of their opinions on the current methods of producing ethanol - the ethanol industry is still in its infancy. The current methods of ethanol production are almost irrelevant when there are such potentially huge gains in efficiency like this.

When you combine this with the inevitable shift to more efficient (and hopefully non-food based) feedstocks, I am confident this will be a sustainable industry.

It would be nice to know if this process is compatible with other types of alcohols. Namely, butanol.


Angelo: I'm not sure the process is useful for butanol, as it is poorly miscible with water.

Jim G


if naysaying ethanol seems excessive on GCC I think this is more of a reflection of negative media coverage of ethanol in general. At least here in the USA, a lot of hot air has gone into the steering of public opinion against ethanol often from magazines whose inside covers generally consist of advertisements for for by big oil companies (e.g. Newsweek, US News, the Economist etc.). And the same is true of peak oil fear mongering books like Robert Heinberg's.

One claim that's been parroted everywhere is one from David Pimentel of Cornell way back in the day that the EROEI from corn ethanol is negative. Yet, as you noted, technology just isn't static like that. It's like someone before automobiles were invented arguing that to support all the drivers we actually have on roads in 2007 you'd need to plant ten times the world's farm acreage in oats to feed all the horses. In reality, when competent manufacturers produce this stuff day in, day out, they observe what obstacles are holding back production and they figure out how to eke ever more output from the same input. And today you've got so much more technology, plus ethanol is already cheaper in the marketplace than oil. I could be wrong, but I suspect a few billionaires will be looking back on this in many years' time, kicking themselves for not having invested in it back in the day.

Reality Czech

If the fiber material is compatible with butanol it would probably work with it (the fiber is permeable to water and shouldn't discriminate between alcohols which don't dissolve in it), but the requirement to evaporate all the water would have a large energy demand.

Butanol is soluble in hydrocarbons, so the easiest way to separate it might be to just stir some oil through the mix.


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Excellent example. The views of Pimentel (and his partner in crime from Berkeley, Tad Patzek) seem to be referenced in 90% of the editorials on ethanol, even though they deviate significantly from nearly every other legitimate (and more recent) study of ethanol EROEI. Perhaps I'm too much of an optimist, but I keep hoping that people who care enough about such matters to participate on this site would at least be objective.


If I've ever badmouthed ethanol (I don't think I ever actually done that) it would be more likely the result of some really stupid (corny) adds here in Canada here in favour of corn/grain ethanol. One add I remember was trying to tell us that it's ok to drive the biggest SUV you can find because, if you fill it with ethanol, your as green as grass. Personally I would hate to see anything get in the way of efficient, clean, quiet EVs.


I personally have no problem with ethanol as a transportation fuel. To get the highest efficiency from it, requires a modified engine.

I think BioDiesel - in the short term - is a better way to go. Mixing in ethanol as in the O2 method also makes a lot of sense.

A turbo-charged BioDiesel hybrid makes even more sense. As far as I know, nobody is even thinking about doing that now.


It does seem like Biodiesel cold more easily mesh with the existing infrastructure, but the only part I question is the supply. Without a breakthrough in algae-based bio-oil, where is it going to come from? I thought the yields for most of the current biodiesel feedstocks (soybeans) were even worse than corn-based ethanol, in terms of the amount of energy from an acre of land. Am I wrong about this??


"...the result of some really stupid (corny) adds here in Canada here in favour of corn/grain ethanol."

Admittedly, living in the northeast, the ethanol adds I see are few and far between. Every now and then I do catch one when watching an out-of-market baseball game from the MLB package that I have. I'll admit - they are quite amusing. I would also say that they serve a purpose in the end. As long as demand for ethanol keeps going up, investments in alternatives to corn/grain based ethanol will keep going up, because that is the only way supply will match demand.


"The Vaperma process allows for significant energy savings because the membrane eliminates distillation and molecular sieve units. By replacing these, GreenField would be able to save up to 40 per cent in energy costs."

Can someone correct me if I am wrong but this seems a bit misleading. To me this is saying that after the mash is fermented then it is put into this process and out comes 99% pure ethanol. That is what I would take as eliminating the distillation process.

However in the diagram the beer is still distilled from the 10% concentration (which seems very high) to the hot 40:60 ratio gas that is the product of the beer column. This is what takes a lot of the energy. All this process seems to be is a better method of drying the ethanol after it is distilled. I really don't see a 40% saving in energy.


Solar, wind, tidal generated power and EVs = > than all.

Hydrogen is classic carrot on a stick. Biofuels are a comletely different environmental nightmare waiting to happen.


So, Chillpill.....

Until that time that we have the infrastructure in place to produce all of the electricity from solar/wind/tidal and have replaced our entire fleet with EVs, what do you suggest we do? Nothing?

I just love comments like that - the author's believe themselves to be so profound - as if they are teaching the rest of us something we don't already know. All or nothing....yeah, that's a great approach. What, cold fusion isn't a part of your equation?

Everyone understands that biofuels are bridging technologies. Something that is better than what we have until all of the ICEs have been phase out of existence. This, however, is not going to happen within the next 20 years.


Butanol is actually much easier to separate through a membrane then ethanol (due to butanols much higher hydrophobicity), and butanol has to use such a method because distilling butanol is to energy expensive (because butanol has a higher boiling point then water).

John Schreiber

@ Ender
The 10% beer is a reasonable number especially if it is a continuous rather than a batch process. Fermentation activities try to balance percentage yield of alcohol over time. Many yeast strains can do work to 12% and industry will push that limit with GMOs. One of the cool ideas relating to butanol is that it could be "floated" off of the fermentation vat.
Commercial stills use heat to process aqueous alcohol blends to about 90% or 180 proof. This process saves energy by only distilling (with heat) to 80~100 proof.


Angelo:  Even if Pimentel is wrong and the EROI of ethanol is 1.5:1 (and reaches 2.0:1 with this improvement), it doesn't matter much.  We would still be faced with a mere 16 billion gallons/year net of ethanol using the entire US corn crop (equivalent to about 10 billion gallons of gasoline).  Nothing in the distillation process can change the gross yield or the limits of agriculture.

Ethanol is a farm-price support program, which is (ironically)about to be shut down because it is too successful.  The public will soon demand that their taxes not be used to drive up the price of food for the sake of motor fuel.


John Schreiber - "Commercial stills use heat to process aqueous alcohol blends to about 90% or 180 proof. This process saves energy by only distilling (with heat) to 80~100 proof."

I guess so however most of the energy is contained in the boiling beer. Boiling for a little bit less time I really do not think will save 40% of the fuel used to heat the beer. Also this process does nothing do save energy in cooking the mash, transporting the corn to the plant, processing the feedstock etc.

To me the 40% saving seems misleading - where did they get this figure from I wonder?


Regarding the issue on ethanol production is increasing the food prices, it's just excellent. What the third world needs is just that, a higher world market price on grain and food. The agriculture is the backbone of these countries and since we had very low prices on food the last 20-30 years these countries has been unable to increase their income. To further limit their chance to get into the market we in the EU and US have put tolls on import of these goods to protect our inner markets.

The era of nearly free food is over, and finally these countries can produce goods we are interested of and can't put tolls on. One good example of this is the new agreement between EU and Brazil regarding sugarecane ethanol to be imported.

So, in the short run the increased food prices is alarming and the UN tells the world we can't feed the hungry, but in the long run this is necessary for these countries to establish their own strong agricultural market. Just plain national economy functions.


I think the 40% efficiency gain that they speak of comes mostly from the fact that they don't need to use a molecular seive. The maximum ethanol to water ratio that you can get off of a still is 90% 10%. To bring the alcohol from 90% purity to 99% purity, it is normally run through a zeolite compound (molecular seive)to soak up that last little bit of water. After each production run, the zeolite has to be heated up to drive off that water. This regeneration process requires alot of energy, because the zeolite really wants to hold on to that water.


Engineer: This improvement is completely independent of improvements to ethanol feedstocks. Again, no one suggested "corn kernel" based ethanol is the future. Even if we were just to start utilizing a portion of the remaining corn plant, we should easily be able to get that EROEI above 3:1. EROEI of 10:1 is absolutely feasible using low-maintenance perennials like switchgrass and miscanthus. Additionally, they can be cultivated in land that otherwise has no practical agricultural use, further expanding our production capabilities. Alcohol-based biofuels can be a big part of the solution.


Using switchgrass or Miscanthus (or corn stalks or willow chips) means a whole new bunch of technical problems, starting with the need to break down extremely tough fibers, going on to using the fragile bugs which can ferment C-5 sugars, and then distilling the very weak alcohol solution that those bugs can tolerate.  Robert Rapier has blogged on this at length.

Once around those problems, you're faced with the very low efficiency of the internal combustion engine.  We are far better off going to electricity as the medium for transport energy than trying to force everything to fit the Procrustean bed of liquid fuels and piston engines.


coal burner:  That's very interesting, because ethanol only needs to be fully dehydrated if it is going to be blended with gasoline.  95% (190 proof) would be sufficient if it was to be used in a separate fuel system as an octane booster (like the Ford-MIT turbocharged direct-injection concept).  The ethanol would allow a savings of 30% in total fuel requirements by boosting engine efficiency; nowhere near enough for sustainability, but far better than current practice.

All these schemes for adding ethanol to gasoline are barking up the wrong tree.

Onother positive effect of increased grain ethanol production is the possibility to put an end to all farm-price support programs in Europe, USA, Canada etc.

Of course, third world poorer countries would also benefit by producing feedstocks or the finish product for their own use or for export.

Farmers, with much higher prices for just about every thing they produce + a new market for grain and cellulosic ethanol feedstocks would no longer require direct or indirect grants.

Secondly, when our farmers make much more profits, governments could (should) collect more taxes instead of giving subsidies. In a country the size of USA this could mean a yearly net difference of about ($25 billions + $25 billions = $50 billions) from subsidies removable + new taxes.

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