Orbital and Bajaj Expand Direct Injection Partnership to Gas-Fueled Three-Wheelers
European Parliament Pushes Back Implementation of Euro 5 Standards

Purdue Team Develops New Front-End Process for Corn Ethanol

Researchers at Purdue University have developed a new front-end processing technique for the production of ethanol from corn that is more environmentally friendly and less costly than conventional wet- or dry-milling processes.

Called the Chen-Xu method after the two developers—Li-fu Chen and Qin Xu—the process produces corn oil, corn fiber, gluten and zein as byproducts of ethanol production. Zein is a protein that can be used in the manufacture of plastics.

With the dry milling process, DDG are produced after fermentation and distillation of ethanol. A centrifuge is used to extract DDG from the residual after ethanol is distilled from the distiller. The co-products of the Chen-Xu method are extracted before fermentation, however, and a centrifuge is not needed.

The Chen-Xu Method produces about 2.85 gallons of ethanol for every bushel of corn processed. That output is slightly higher than current methods, but the same process that creates the ethanol also creates other marketable products. Furthermore, total processing time from corn to ethanol is expected to be less than 24 hours. While fermentation with the dry-milling process can take 48 hours, with the Chen and Xu method, it takes only 4 hours.

Throughput is lower than in conventional processes, however.

Chen said the method also meets federal Clean Air Act standards, eliminating costs that other methods incur in meeting environmental regulations. Both wet- and dry-milling ethanol plants have had environmental problems in the form of pollutants and offensive odor. In 2002, twelve Minnesota ethanol plants were fined by US Department of Justice for violation of Clean Air Act and each agreed to spend more than $2 million for installation of control devices to reduce air pollutants, which were caused primarily by the manufacturing of Dry Distiller Grain animal feed.

In 2003, Archer Daniels Midland agreed to spend $340 million over 10 years for installation of control devices to reduce air pollutants from its processing plants. The EPA estimated about 90% of ADM’s pollution violations stemmed from the company’s corn processing and ethanol operations.

One of the common methods of manufacturing ethanol, called dry milling, is often the cause of air pollutants by drying and storage of DDG, a byproduct of the process. Another method—wet milling—produces an odor because it requires the input of sulfur dioxide. The Chen-Xu Method eliminates both issues, and the only odor comes from the smell of the corn and yeast fermentation.

—Li-fu Chen

Using a machine originally designed to make plastics, the Chen-Xu Method grinds corn kernels and liquefies starch with high temperatures. The water input required by wet milling is reduced by 90%, according to Chen. Wastewater output is cut by 95%, and electricity use is reduced by 47%.

The total operating cost of a Chen-Xu Method ethanol plant should be much less than that of a wet-milling plant, and total equipment investment is less than half. And with proper planning and management, total equipment investment should be less than that of a dry-milling plant.

—Li-fu Chen

Funding for the work came from industry donations and one year of support from the Value-Added Grant Program of the Indiana State Department of Agriculture. Chen said the next step for the fledgling company is to commercialize the technology worldwide. The technology was licensed to Bio Processing Technology Inc. through the Office of Technology Commercialization, a division of Purdue Research Foundation.



This seems to be an excellent incremental improvment to the ethanol production process. The reduced emissions, water use, wastewater discharge and electricity consumption will all reduce the environmental footprint of ethanol production from corn.

I wonder what the direct energy inputs are like compared to wet and dry milling processes. Coal or natural gas consumption for process energy at ethanol production plants is the main contributor to fossil energy inputs and greenhouse gas emissions in a well-to-wheels ethanol production pathway. Reducing these inputs is thus the greatest lever to increase ethanol's net energy ratio and reduce well-to-wheels greenhouse gas emissions.


This really does sound good. Amazing what can be done when you get some good minds working on a problem. Good use of grant funds here.

Max Reid

Great step ahead.

40 Ethanol plants are under construction and this is what has scared oil companies to reduce the prices.

There is a hope that Ethanol would reduce the impact of Oil shortage.

Herbert Ray

I would like to do a feasibility study for a small size plant.
Where can I get the capacity of the various unit operations and processes of the plant that was used to validate the process modifications?
I would also like to know if flowsheets, such as PFDs, P&IDs, Equipment lists, sizes, list of vendors of equipment,capital costs, operating costs, Life cycle costs were developed.
Would appreciate if you can give me the contact information on who I should talk to.

Thanks and best of regards,

The comments to this entry are closed.