Idea fosters cost-efficient ethanol production

An engineer looks at refining a byproduct into methane, and using that gas to power the plant.

Patrick Hirl, an engineer with Muscatine-based Stanley Consultants, believes he’s figured out a way to make ethanol manufacturing more energy-efficient by unlocking additional energy already contained in corn plants.

Hirl, who has applied for a patent on his invention, came at the process from a different angle than most ethanol researchers.

He had tried for years to devise a cost-effective way to retrieve methane gas from farm manure. He finally gave up when he realized that the digestive systems of farm animals were so efficient that the amount of gas left in their waste would not produce a minimum return on investment of 12 to 15 percent, which Hirl believed was needed to make the effort a commercial success.

By comparison, he said, his new process should produce a return on investment of 20 to 30 percent, which should make it attractive to ethanol producers.

Des Moines Register