US 7,118,655 B1 · Direct synthesis of hydrazine through nitrogen fixation by means of two-photon absorptions

Abstract

Two methods and apparatuses are described for hydrazine synthesis through nitrogen fixation induced by photoexcitation of N2. Both methods of photoexcitation of N2 for hydrazine synthesis involve a two-photon absorption process. The first method of N2 fixation with H2 uses a high-energy short-pulsed Nd: YAG laser with wavelength of 1.06 μm. The two-photon absorption of N2 is followed by a vibrational-vibrational (V—V) energy transfer that leads to a near-complete population inversion of N2 vibrational states. The energy separation of these states is larger than the activation energy needed for N2H4 formation. The second method of N2 fixation with H2O uses a high-energy short-pulsed blue laser with wavelength of 0.4 μm. The two-photon absorption at 0.4 μm pumps N2 to a highly excited vibrational state, which has enough energy to both dissociate H2O into H2 and O2, and to react with H2 to form N2H4 as in the above direct method of N2 fixation with H2.

Claims18

Dependent claims

A process for producing hydrazine with nitrogen and hydrogen as raw materials, comprising the steps of:

(A) generating photons from a high-energy laser pulsed source, with pulse energy at least 105 J per pulse;
(B) passing said photons through a laser amplifier pumped by an arc lamp to produce photons with increased pulsed intensity, with pulse intensities at least 1011 W/cm2;
(C) introducing said intensified pulsed laser photons to excite nitrogen molecules from said nitrogen raw materials through two-photon absorptions so that said nitrogen molecules are induced to make transitions from a ground vibrational state thereof to excited vibrational states;
(D) flowing said excited nitrogen molecules to a high-pressure vessel so as to cause effective collisional-mixing leading to a new vibrational energy state;
(E) flowing said nitrogen molecules at said new vibrational energy state from said high-pressure vessel to a container containing hydrogen from said hydrogen raw materials which reacts with said new vibrationally excited nitrogen molecules to form hydrazine;
and
(F) cooling said hydrazine and leading to a liquid form of output.

4 more elements

Dependencies are inferred from the claim text.

Direct synthesis of hydrazine through nitrogen fixation by means of two-photon absorptions

Life of this patent

Direct synthesis of hydrazine through nitrogen fixation by means of two-photon absorptions

Life of this patent

Abstract

Claims18