Compositions – Chemically interactive reactants – Inorganic reactants only
Reexamination Certificate
1999-11-16
2001-05-01
Anthony, Joseph D. (Department: 1714)
Compositions
Chemically interactive reactants
Inorganic reactants only
C252S186280, C252S186430, C252S001000, C423S584000, C372S089000, C372S055000
Reexamination Certificate
active
06224786
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to chemical laser systems, and more particularly to a basic hydrogen peroxide composition and a method of making the same, wherein the basic hydrogen peroxide composition does not freeze or crystallize during routine operation of a chemical oxygen iodine laser (COIL) system.
BACKGROUND OF THE INVENTION
The fact that an atom will emit a photon of radiation when one of its electrons drops to a lower energy state has enabled the laser to be employed in a number of military, industrial, and medical applications. The term “laser” is an acronym for light amplification by stimulated emission of radiation. In its simplest form, a laser consists of a rod of transparent crystal or a tube filled with gas or liquid. A mirror is placed at one end and a half-silvered mirror at the other end. The laser is then “pumped” by adding energy, e.g., by shining another light source into it, by adding electrical energy, or by stimulating a chemical reaction. This process raises electrons in the laser to higher energy states.
During the pumping process, some of the electrons will spontaneously fall back to a lower energy state, emitting photons. The photons that travel toward the sides of the laser are quickly lost, but those traveling along the length of the rod or tube are reflected back by the mirrors. This activity generally occurs in the area commonly referred to as the laser gain region. When these photons strike other excited atoms, they stimulate those atoms to release photons of the exact same energy level (or wavelength), which travel in the same direction as the stimulating photons. The result is an intense, highly focused beam of light escaping through the half-silvered end of the laser. This light beam is generally referred to as a beam of high energy coherent radiation, or more commonly, a laser beam.
Because the photon wavelength is determined by the characteristics of the atoms in the lasing material, laser light is of a single wavelength. Because laser light travels in a tight beam, it can carry a great deal of energy over a great distance without significant loss. With respect to recent developments in laser technology, there has been increased interest in chemical laser systems, especially COIL systems.
The COIL system was initially developed for military applications;
however, recent attention has turned to potential industrial uses of COIL systems, such as metal cutting applications.
In a COIL system, chlorine gas reacts with a solution of basic hydrogen peroxide (i.e., usually KOH or NaOH mixed with hydrogen peroxide) to produce a gaseous flow of excited oxygen, also referred to as singlet delta oxygen or singlet molecular oxygen (designated as O
2
*, O
2
(
1
&Dgr;), as well as by other symbols). This gaseous flow of singlet delta oxygen collides (typically at speeds approaching or even exceeding the speed of sound) with iodine gas molecules (i.e., I
2
), dissociating them and exciting the resulting iodine atoms (i.e., I), which lase at 1.315 &mgr;m. The major laser byproducts are various salts (e.g., NaCl or KCl) and heat. The small amounts of iodine can be scrubbed from the output.
The intended operation of a conventional COIL system can be summarized as follows. The initial step is to generate the singlet delta oxygen. This is accomplished by providing a source of basic hydrogen peroxide, typically in liquid form, and a source of molecular chlorine, typically in gaseous form. These two materials are then charged or injected into a singlet delta oxygen generator through appropriate manifold/conduit assemblies, respectively. The resulting exothermic reaction between the basic hydrogen peroxide liquid and the molecular chlorine gas produces the gaseous singlet delta oxygen, as well as several by-products, such as salt and heat. The heat can be removed by appropriate devices such as a heat exchanger, and the salt can be removed by appropriate devices such as a scrubber.
Once the gaseous singlet delta oxygen is generated, it is then charged or injected in flow form into a mixing nozzle at the appropriate time. The mixing nozzle has a throat portion which generally divides the mixing nozzle into a subsonic zone and a supersonic zone; that is, the flow of gaseous singlet delta oxygen is subsonic in one portion of the mixing nozzle and supersonic at the other portion of the mixing nozzle. The mixing of reactants is typically done in the subsonic zone.
A molecular iodine generator is in communication with the mixing nozzle by an appropriate manifold/conduit assembly. At the appropriate time, gaseous molecular iodine is then charged or injected into the mixing nozzle in such a manner so as to let it “pool” before completely mixing with the singlet delta oxygen gas flowing from the singlet delta oxygen generator. The slight delay in mixing due to this “pooling” permits the singlet delta oxygen to dissociate only some of the molecular iodine on the edge of the “pool” and thus initiate the chain reaction dissociation by the product atomic iodine.
The primary reactions taking place in connection with the conventional COIL system are as follows:
(1) I
2
+O
2*
→I
2
*+O
2
. That is, a mole of molecular iodine reacts with a mole of singlet delta oxygen to produce a mole of excited molecular iodine and a mole of molecular oxygen.
(2) I
2
*+O
2
*→2I+O
2
. That is, a mole of excited molecular iodine reacts with a mole of singlet delta oxygen to produce two moles of atomic iodine and a mole of molecular oxygen.
(3) I+O
2
*→I*+O
2
. That is, a mole of atomic iodine reacts with a mole of singlet delta oxygen to produce a mole of excited atomic iodine and a mole of molecular oxygen.
(4) I*→I+hv. That is, a mole of excited atomic iodine releases a photon (hv), thus producing a mole of atomic iodine.
The singlet delta oxygen gas flow initially contacts the gaseous molecular iodine “pool” at subsonic speed; however, the singlet delta oxygen gas flow is quickly brought up to near supersonic or even supersonic speed (via appropriate devices such as a venturi) and is expelled out through the mixing nozzle into the area known as the laser gain region. It is in this area where the excited atomic iodine releases its photon. The released photon is then reflected many times between a set of mirrors, the first mirror being fully reflective, the second mirror being partially reflective. The reflected photons eventually form a laser beam, which is transmitted through the partially reflective mirror at a wavelength of 1.315 &mgr;m. Any remaining chemical species are removed from the laser gain region by a combination of exhaust assemblies and scrubber assemblies in order to avoid contamination of the laser's mirrors.
At times, the COIL system experiences unpredictable and unexplainable anomalous freezing of the potassium basic hydrogen peroxide (K-BHP) even though the system was operating at temperatures 10° C. above the known freezing point of the BHP. The formation of solids in the BHP plugs the singlet oxygen generator and causes the laser to cease operating. That fact that the system operates without a problem on some occasions, and at the same conditions it unexpectedly freezes on other occasions has defied explanation since the system is operating well above the known freezing point of BHP. This problem has occurred at numerous COIL system facilities and has been an ongoing problem for the COIL system for several years.
Accordingly, there has been increased interest involving the part of the process that involves BHP. Generally, the BHP is prepared by reacting aqueous solutions of KOH and H
2
O
2
to form aqueous KOOH. The accepted phase diagram for the KOH, H
2
O
2
, H
2
O system was determined by Dobrynina, et al., Bulletin of the Academy of Sciences, USSR, Division of Chemical Sciences, Volume 34, Page 2451 (1968). The phase diagram is shown in
FIG. 1
after re-plotting their data on a KOH, H
2
O
2
, and H
2
O axis system.
Referring to
FIG. 1
, a phase diagram for K-BHP, expressed in weight
Anthony Joseph D.
Harness & Dickey & Pierce P.L.C.
The Boeing Company
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