Articles

Revolutionizing the Ethanol Production Process

Biofuels Canada Magazine
2007, October Issue

by Khalila Sawyer

Vaperma’s hollow fibre polymeric membrane is a made-in-Canada technology that represents a new "dewatering" process for the production of fuel ethanol. The trademarked hollow fibre technology called the "Siftek" membrane allows for the highly selective separation of water from various gas mixtures and organic vapours. The heat and solvent-resistant membranes offer an alternative to conventional ethanol dehydration processes and the removal of CO₂.

The membrane contains approximately 15,000 hollow polymer fibres that are cut into two-metre lengths and are embedded, bundled and packed into a single removable cartridge. The cartridge is then housed in a module and is inserted into a pressure vessel. The membrane itself is composed of an inner and outer layer each with its own properties. The inner "active" layer is where the separation occurs, while the outer "porous sublayer" draws the water vapour out. Both layers are no more than 0.2mm thick.

How it works

When a wet, pressurized gas flows through the membrane, water vapour is absorbed by the inner layer and is then drawn out and diffused into the outer layer. During the ethanol production process, the fuel is "dewatered" by selective permeation of water vapour through the membrane. The water vapour is better able to permeate across the membrane at a much greater flux than ethanol is due to its relatively high absorption and diffusion rates of the polymer formulation of the fabrication process.

After the initial evaporation of the ethanol/water feed, the remaining gas has a 40 per cent to 60 per cent ethanol content. The blend passes through the first membrane module where 90 per cent of the water is removed. The water is then pumped out, condensed and directed towards the front end of the plant. The remaining fuel flows through a second series of modules where any remaining water is removed. The result is a 99 per cent pure fuel-grade ethanol product.

Vaperma’s unique process has the potential to dramatically improve the ethanol production process. With no distillation of the ethanol/water blend after evaporation needed, ethanol producers could see energy savings as high as 40 per cent by replacing the distillation column and the molecular sieve units used in a conventional ethanol plant. Energy savings are due mainly to the efficiency of the membrane’s ability to remove large amounts of water in a continuous process without a change in phase coupled with an advanced heat recovery concept.

The entire process is completed in one continuous step and less than 2 per cent of the ethanol is recirculated compared to 38 per cent to 48 per cent with molecular sieves. "This is a net savings of 1.7 cents per litre (7 cents a gallon) for the ethanol producer," says Claude Letourneau, president and CEO of Vaperma. In addition, the technology is easily integrated into new or existing facilities, requires approximately 1/3 of the space used for distillation and molecular sieve units and can be easily expanded by installing additional membrane modules. Since the back end of any ethanol process is where the water is driven off, it would apply to any ethanol production procedure. The Siftek™ process can also be applied to any type of biomass feedstocks such as corn, sugar-cane, wheat, and cellulosic biomass. Lastly, no waste liquid waste is generated as the permeate is mostly water that can be recycled to the front end of the ethanol plant. This reduces the amount of make-up water.

Current Projects

Recently, Vaperma partnered with GreenField Ethanol, Canada’s leading ethanol producer, and EnCana Corp., a North American unconventional natural gas and integrated oilsands company, to research and test the Siftek™ membrane technology. Talks between Vaperma and GreenField initially began two years ago when the companies considered installing a demonstration plant at GreenField’s Tiverton, Ontario, ethanol facility.

"[Vaperma’s] aim was to convince GreenField of three things: that the Siftek™ membrane would perform in such a way that it would not dissolve in ethanol, that it could create 99 per cent ethanol purity, and that we could deliver a system that could easily adapt to their facility," Letourneau says. "The project was deemed successful within the first six months which demonstrated the stability of the polymer membrane."

Vaperma’s pre-commercial membrane spinning facility went online soon afterwards in August 2006 and spun enough fibres to enable testing at a larger demonstration facility in Tiverton. The resulting project was the first large-scale demonstration of the membrane technology for dewatering ethanol in North America.

GreenField was so enthusiastic with the first phase, that Vaperma will expand the second phase of its demonstration to GreenField’s Chatham location. In the second phase, Vaperma will tweak its beer column to see if it can increase its current 40 per cent to 60 per cent ethanol content to 50 per cent to 60 per cent after evaporation of the ethanol/water feed occurs.

"As Canada's leading renewable fuels producer, GreenField was eager to test the Vaperma process since it would save money and help the environment," says Robert Gallant, president and CEO of GreenField. "And while saving money appeals to any business, the second factor was equally important because it is consistent with our vision to do business in the most environmentally responsible manner possible."

According to Pierre Côté, CTO of Vaperma, who delivered a lecture on the successful trial demonstration in Tiverton at this year’s Fuel Ethanol Workshop, after corn, steam is the most important cost in the production of ethanol, representing approximately 15 per cent of the total ethanol production cost.

"The unit in Tiverton used substantially less energy and therefore fewer greenhouse gases were created in the process—reducing the plant's CO₂ footprint," Gallant says. "While our plants are all extremely efficient, the less natural gas we use to make steam, the better for the environment."

In addition to its research collaborations with GreenField, this summer Vaperma opened its new 22,000 square-foot research and technology centre for the development and pilot testing of clean energy gas separation membranes in St-Roumald Quebec. The facility will be primarily used to develop, test and improve the Siftek™ membrane. The centre will be the hub for the manufacture and design of the membrane. It will also house the company’s headquarters, engineering department, and experimental lab for membrane production, as well as an analytical lab for quality control and a pre-commercial membrane production line.

Funding support came from Sustainable Development Technology Canada, Encana’s Environmental Innovation Fund, and Natural Resources Canada who contributed a collective $7 million towards the project.

Outlook for the future

As Côté expressed in his lecture, the new membrane technology will become an attractive solution to ethanol producers for a number of reasons. Most importantly while ethanol producers cannot control the cost of raw materials, they can reduce the processing costs with innovative technologies. Vaperma expects that the new membrane will be most appealing to ethanol producers in North America and Brazil to meet the growing needs of the ethanol industries.

"Our first market is the Canadian ethanol industry, specifically GreenField Ethanol," Letourneau says. "After that, we hope to sell worldwide to all ethanol producers." The company has already been in talks with a number of U.S. companies and is strategically positioning with the sugar cane industry in Brazil.

At present, Vaperma sees no major obstacles before its Siftek™ membrane becomes a commercial product in 2008. The company is moving right along, according to Letourneau, and has already secured the proper funding. The company’s only challenge will be to balance project development, testing and manufacturing, which Letourneau says all companies deal with. Some industry competition are also researching similar products. Mitsui & Co. Ltd, which is involved in energy-related business activities and providing stable supplies worldwide, is aggressively marketing a ceramic membrane, one that Letourneau thinks has the same possibilities as Vaperma’s polymer membrane but with the drawback of higher capital costs. Despite other research and developments made by the competition, Vaperma remains optimistic about its new Siftek membrane with industrial scale commercialization projected for next year.

Khalila Sawyer is the managing editor of Biofuels Canada. Reach her at ksawyer@bbibiofuels.com or (519) 576-4500.