miércoles, 24 de junio de 2009

Plumas carbonizadas de gallina para almacenar hidrógeno/Carbonized chicken feathers for hydrogen storing

Científicos de Delaware afirman que han desarrollado un nuevo método para almacenar hidrógeno usando fibras de plumas carbonizadas de gallina, que pueden contener grandes cantidades del gas, una fuente muy prometedora y con un coste mucho más bajo que otros sistemas.
Según P. Wool, Ph.D., Profesor de Ingeniería Química en la Universidad de Delaware in Newark, "Las fibras carbonizadas de pluma de gallina tienen potencial para mejorar de forma dramática los rendimientos de otros métodos de almacenamineto de hidrogeno, y quizás puedan facilitar el camino para el desarrollo práctico de una economía basada en el hidrógeno"
Las fibras de pluma de gallina están compuestas mayoritariamente por queratina, una proteína natural que forma tubos huecos y muy robustos. Al calentarla, la proteína se entrecruza reforzando su estructura, y se vuelve más porosa aumentando su área superficial. El resultado final son fibras carbonizadas de plumas de gallina, que pueden absorber tanto o más hidrógeno que los nanotubos de carbono o los hidruros metálicos, los otros dos materiales que se están estudiando por su potencial para almacenar hidrógeno.
Según Wool, la utilización de estas plumas carbonizadas solo añadiría 140 € al precio de un coche. A modo de comparación, un tanque de combustible de 20 galones (75 litros) de hidrógeno hecho con nanotubos de carbono, costaría 3.800.000 €, mientras que uno con hidruros metálicos costaría 21.000 €.

Scientists in Delaware say they have developed a new hydrogen storage method — carbonized chicken feather fibers — that can hold vast amounts of hydrogen, a promising but difficult to corral fuel source, and do it at a far lower cost than other hydrogen storage systems under consideration.
"Carbonized chicken feather fibers have the potential to dramatically improve upon existing methods of hydrogen storage and perhaps pave the way for the practical development of a truly hydrogen-based energy economy," says Richard P. Wool, Ph.D., professor of chemical engineering at the University of Delaware in Newark.
Chicken feather fibers are mostly composed of keratin, a natural protein that forms strong, hollow tubes. When heated, this protein creates crosslinks, which strengthen its structure, and becomes more porous, increasing its surface area. The net result is carbonized chicken feather fibers, which can absorb as much or perhaps more hydrogen than carbon nanotubes or metal hydrides, two other materials being studied for their hydrogen storage potential.
Using carbonized chicken feathers would only add about $200 to the price of a car, according to Wool. By comparison, making a 20-gallon hydrogen fuel tank that uses carbon nanotubes could cost $5.5 million; one that uses metal hydrides could cost up to $30,000, Wool says.

Tomado de/Taken from Eureka Alert

Resumen de la Comunicación/Summary of the Communication
13th Annual green Chemistry & Engineering Conference
Erman Şenöz , Chemical Engineering Department, University of Delaware, Newark, DE
Richard P. Wool , Chemical Engineering Department, University of Delaware, Newark, DE
The biggest obstacles to a hydrogen powered energy economy are the production and storage of hydrogen. The Department of Energy’s (DOE) 2010 and 2015 hydrogen storage targets are quite challenging in terms of gravimetric capacity (6 wt% and 9 wt% respectively), volumetric capacity (45 and 81 grams H2 per L) and storage cost ($4 and $2 per kWh respectively). In order to solve the H2 storage problem, various kinds of nano-structured materials have been investigated and produced, none of which could fulfill these targets entirely. Their disposal methods and degradability are still a big question mark. Additionally, the prices of these materials are extremely expensive. It is crucial that the material that will serve as a hydrogen adsorbent in fuel cell vehicles is cheap and is environmentally.
The goal of this project is to develop new low cost hydrogen storage substrates from a waste material (6 billion lbs/yr in U.S.) —chicken feathers. The results showed that carbonized chicken feathers (CCFF) have the potential to meet the DOE requirements for H2 storage and are competitive with carbon nanotubes and metal hydrides at a tiny fraction of the cost. When keratin based chicken feathers are heat treated by controlled pyrolysis, hollow carbon microtubes are formed with nanoporous walls. Their specific surface area increases up to 450 m2/g by the formation of fractals and micropores thus enabling more hydrogen adsorption than raw (untreated) feather fibers. Experimental hydrogen storage optimization results and surface characterization of CCFF by SEM, XPS and N2 adsorption will be demonstrated. Furthermore, recent findings on heat treatment of chicken feather fibers by thermal analysis techniques will be discussed in detail.

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