USA awarded patent on method for producing renewable high-density biofuels from pinene

30 July 2012

The United States of America, as represented by the Secretary of the Navy, has been awarded a patent (Nº 8,227,651) on a method for producing high-density fuel candidates from the selective dimerization of pinenes. (Earlier post.) These renewable fuels have potential for use in rocket engines and in a wide variety of jet or turbine engines.

Nafion, Nafion SAC-13, and Montmorillonite K-10 (MMT-K10) are effective catalysts for the reaction. (Nafion can produce dimers in up to 90% yield.) Pinene dimers synthesized with these heterogenous catalysts have a density and net heat of combustion comparable to JP-10.

Conventional, petroleum-based, high-density tactical fuels such as JP-10 and RJ-5...will be particularly hard to replace given their high densities of 0.94 g/mL and 1.08 g/mL, respectively. In the case of RJ-5 (perhydroinorbornadiene), significant ring strain contributes to a high heat of combustion. Although bulk agricultural waste products such as cellulose and lignin are often targeted as feedstocks for the production of renewable fuels, even saturated hydrocarbon fuels which have previously been prepared from the dehydration products of cellulose-derived alcohols have a density of only 0.78 g/mL...while JP-5 which contains aromatic compounds typically has a density of 0.83 g/mL.

These lower densities are reflected in the volumetric heating value of these fuels, with cellulose-based jet or turbine fuels and JP-5 capable of producing only 34.3 MJ/L and 34.8 MJ/L, respectively, compared to 39.6 MJ/L for JP-10 and 44.9 MJ/L for RJ-5.

—US Patent 8,227,651

The process was developed at the Naval Air Warfare Center, Weapons Division (NAWCWD) at China Lake. Members of the team described aspects of the process in a paper in the journal Fuel earlier this year.

Resources

• Heather A. Meylemans, Roxanne L. Quintana, Benjamin G. Harvey (2012) Efficient conversion of pure and mixed terpene feedstocks to high density fuels, Fuel, Volume 97 Pages 560-568 doi: 10.1016/j.fuel.2012.01.062