Energy-Harvesting Reactor Based on Diffusion of Aluminum in Gallium

Abstract

Aluminum may be used as a fuel source to power small vehicles, unmanned vehicles or underwater vehicles, other small robotics, backup or regular underwater power sources (e.g., for oil rigs), or as an emergency power source in flooded or disaster areas. Reactors are described that harvest energy produced by the exothermic oxidative reaction of aluminum or an aluminum alloy with water, with the assistance of liquid gallium as a depassivating agent.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority to U.S. Provisional Patent Application No. 61 / 636,100 filed Apr. 20, 2012, the disclosure of which is incorporated by reference herein in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]This invention was made with government support under Contract No. FA8721-05-C-0002 awarded by the U.S. Air Force. The U.S. government has certain rights in the invention.TECHNICAL FIELD[0003]The present invention relates to electrochemical reactors, and more particularly, to reactors for the production of energy from the oxidation of aluminum.BACKGROUND ART[0004]It is known in the art that aluminum can be used as a fuel for the production of hydrogen which can then be harvested or used in fuel cells. But, because aluminum forms a stable protective layer upon oxidation, which limits its further reaction with the oxidant, aluminum-based systems require the use of a depassivating agent...

AI Technical Summary

Benefits of technology

The patent describes systems and methods for producing high thermal energy using a stream of molten depassivating agent, which is circulated through a circuit and reacts with a fuel to produce heat. The systems can be used for powering vehicles like UUVs and UAVs, as well as for backup or emergency power in flooded or disaster areas. The systems use a continuous flow of fluid, which is introduced into a housing and passes through a source of fuel and a source of oxidant. The heat is then converted into electrical energy using a thermal energy harvester and the waste is purified. The patent also describes an electrochemical reactor for energy storage, which uses a continuous circulation of fluid containing predominantly liquid gallium. The system can be equipped with a pump to recirculate the fluid and a centrifuge to remove aluminum oxide from the fluid. The patent also describes a method for using the system, which involves introducing aluminum or an aluminum alloy into the fluid and removing the aluminum oxide from the fluid using a physical or chemical separation system. The technical effects of the patent include the ability to produce high thermal energy using a continuous flow of molten depassivating agent and the use of a continuous circulation of fluid for improved heat transfer.

Problems solved by technology

But, because aluminum forms a stable protective layer upon oxidation, which limits its further reaction with the oxidant, aluminum-based systems require the use of a depassivating agent to remove the oxide layer and expose new reactive surfaces to the oxidant.

Because of the low thermodynamic properties of water, the recovery of the thermal energy produced by the oxidation of aluminum has been ineffective for conversion into another form of energy.

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