Pig power!
New process can turn swine manure into odorless fuel
(October 2008)
The nation's 67 million pigs and hogs may star in a new, but unlikely, role: helping reduce the nation's need for imported oil. A new process, known as wet gasification, turns swine manure into methane while removing offending odors and killing disease-causing microbes. This catalyzed process was developed by scientists at the Pacific Northwest National Laboratory.
The team used theoretical calculations and related experiment results to show wet gasification has the potential to quickly turn swine waste into energy-packed methane, the chemical responsible for the energy in natural gas. The process uses a specially designed ruthenium-based catalyst, which lets the desired reactions occur in minutes at intensive processing conditions, instead of the days to months required for traditional biological conversion in anaerobic lagoons.
This new process, however, has drawbacks that need to be addressed. For example, sulfur and mineral components must be removed from the waste; otherwise, the catalyst is deactivated. The current research sponsored by the U.S. Department of Energy is underway to demonstrate process modifications to address this issue.
Another drawback is the capital cost. A conceptual wet gasification system for a swine farm costs much more than traditional approaches. However, the new process recovers nitrogen as ammonia, which could be used/sold as a fertilizer, and produces relatively clean water, which could be treated and used with livestock. The solid residue volume from the traditional system, that typically requires land application, is also greatly reduced as a result of the nearly complete conversion of the organic material to product gas in the wet gasification process.
To learn more, read the article in the October 2008 issue of Biomass Magazine or see the article in Industrial and Engineering Chemistry Research.
Reference: Ro, Kyoung, Keri Cantrell, Douglas Elliott, and Patrick G. Hunt. 2007. "Catalytic Wet Gasification of Municipal and Animal Wastes." Industrial and Engineering Chemistry Research 46, 8839-8845.
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