Ammonia salt fuel system

Abstract

The use of a solution of salt within ammonia as a fuel. The preferred ammonia / salt solution is an ammonium nitrate solute (NH4NO3) within the solvent anhydrous ammonia (NH3). The solution may also contain a small amount of water (H2O).

Description

TECHNICAL FIELDThis invention relates to carbon-free fuels. More specifically, this invention relates to the use of an ammoniacal, ammonia salt solution as a fuel.BACKGROUND OF THE INVENTIONIn 2005, the United States Department of Energy (DOE) updated its goals for hydrogen production. The DOE noted that one kilogram of hydrogen contains approximately the same energy as one gallon of gasoline, termed as a gallon of “gasoline equivalent,” or “gge.” The DOE therefore set the goal for the DOE's hydrogen program to develop methods and techniques capable of producing hydrogen for between $2-$3 per gge by 2015. In the intervening three years, the DOE has funded millions of dollars of research at DOE owned federal laboratories to attain this goal. To date, no one has reported any results that have done so.The reason that the DOE is interested in hydrogen is because when burned hydrogen produces no carbon dioxide effluent. As such, hydrogen is a potential fuel that does not generate so-call...

AI Technical Summary

Benefits of technology

The preferred application for this fuel solution is for use in internal combustion engines and gas combustion turbines. The invention improves on prior art ammonia-based fuel mixtures because the addition of salts reduces the vapor pressure of ammonia, allowing it to be stored in tanks at pressures closer to or at atmospheric pressure. The invention also improves on prior art ammonia-based fuel mixtures because it does not contain carbon, which if present would produce undesired carbon dioxide or carbon monoxide upon combustion. The invention also improves on prior art ammonia-based fuel mixtures because it does contain molecularly-fixed oxygen, which increases the combustibility of the mixture relative to pure ammonia when burned in air. The oxygen in the fuel solution also enhances the combustion flame speed relative to pure ammonia, which is of benefit to its use in piston-based and rotary combustion engine applications.

The salt / ammonia solution will also have an increased internal oxygen content when compared to pure ammonia, and increasing amounts of ammonium nitrate within the solution will aid the oxidation of the fuel during its combustion in air. Therefore, the combustibility and flame speed of a fuel solution may also be tuned as appropriate for the intended combustion device by the addition of a specific amount of ammonium nitrate solute to the ammonia solvent. In this manner, the fuel of the present invention may be configured to provide a fuel having a specific combustibility and flame speed for an intended combustion device.

Problems solved by technology

Unfortunately, hydrogen is costly, and is difficult to store and transport.

However, the use of ammonia as an engine fuel is not without drawbacks.

One such drawback is related to the fact that at room temperature and atmospheric pressure, ammonia exists as a vapor.

An additional drawback related to the use of ammonia as a combustion fuel is its limited flammability (16-25% ammonia by volume in air, compared to 4-74% hydrogen in air), as well as its low flame speed (ca.

3.8 m / s for hydrogen), which limits its utility for high-speed engines and burners.