BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the current invention relate to plasma reactors and methods and systems that utilize plasma reactors.

2. Description of the Related Art

Plasma reactors may include at least two electrodes which are spaced apart. Typically, a voltage difference is applied to the electrodes and an electric field is established between them. A stream of gas may be introduced to the space between the electrodes such that it passes through the electric field. Exposure to the electric field generally ionizes the gas and creates a plasma. If a stream of liquid is also introduced to the space between the electrodes, the gas and liquid may form two layers flowing in parallel and a plasma may form in the gas and at the surface of the liquid and further, the ions resulting from the plasma may be injected into, or may otherwise enter into the liquid as it passes through the electric field. Plasma injection into liquid may be utilized for applications such as: in-line liquid hydrocarbon fuel reforming for hydrogen enrichment to improve the fuel economy of internal combustion engines; nitrogen fixing by direct nitrogen ion injection into water; destruction of high molecular weight hydrocarbons (proteins and pharmaceuticals) in drinking water; ammonia/nitrate sequestering for treatment of high nitrate content water; demineralization (water softening) for consumer and industrial markets; nitrification of water for agricultural use; pH modification of liquid streams; disinfection, oxygen and ozone injection; and other similar applications.

In previous reactors that utilize gas and liquid, an eductor design was described (U.S. Pat. Nos. 9,287,800 and 9,394,189B2, Buchanan et al.) which utilized a low pressure zone created by an eductor to enhance the introduction of gas into the reactor and enhance the creation of the plasma all around the area between the first electrode and the liquid. This new and novel laminar flow reactor allows for an increased area of plasma generation with the elimination of the need to adhere to the physical characteristics of an eductor. This new and novel design forces gas into the reactor creating a relatively high pressure zone of gas above the liquid, the area of plasma generation can be greatly extended and the effectiveness of the system enhanced. In addition, previous eductor based reactors required the second electrode be in close proximity and directly in contact with the liquid. In this reactor, the second electrode may contact the liquid but also may be placed in close proximity or further away from the first electrode. In systems where the liquid needs to be electrically isolated from the electrode, the second electrode may be dielectrically isolated from the liquid by a non-conductive layer.

The ionization energy of a gas, or the minimum energy required to produce a plasma of the gas, is the minimum amount of energy required to remove the most loosely bound electron, also known as the valence electron, of an isolated neutral atom, molecule, or ion of the gas. The ionization energy varies for from gas to gas and the form of the gas, and these values are well-known to those skilled in the art. For example, the molar ionization energy of atomic nitrogen is approximately 1402.3 kJ mol−1, atomic oxygen is approximately 1313.9 kJ mol−1, and atomic argon is approximately 1520.6 kJ mol−1. However, in practice, producing ionized gases or plasmas generally requires dissociating molecules of the gas, stripping shared electrons so atoms dissociate, and holding the atoms in an ionized form.

In addition to injection of ionic constituents into a liquid, diffusion or infusion of non-ionic gas constituents into a liquid can be an important component in various industries, including, but not limited to, many agricultural systems and nitrogen mitigation or removal systems. Many of these applications require increased oxygen or other gas constituents in water. Present methods for oxygen diffusion into water consist of diffusion via a bubbler or other type of aeration system. This type of diffusion can be enhanced but requires using higher pressure or alternative expensive methods to increase the amount of oxygen in the water. Further methods consist of forcing small oxygen bubbles through a membrane into water. However, each of these oxygen diffusion methods suffer from loss of significant amounts of oxygen, poor diffusion, and/or substantial monetary costs. Similarly, other systems that attempt to diffuse gas into liquids suffer from low diffusion rates, and saturation using traditional means is limited.

Studies using direct current (DC) electric fields and low frequency electric pulses in water have shown a positive effect on oxygen diffusion. For example, one such study is described inConcentration fields near air-water interfaces during interfacial mass transport: oxygen transport and random square wave analysis, by H. E. Schulz and J. G. Janzen, published in the Braz. J. Chem. Eng. Vol. 26 No. 3, Sao Paulo July/September 2009.

Non-thermal plasmas, which can be produced using a gas adjacent to a liquid in reactors such as those described in U.S. Pat. Nos. 9,287,800, 10,010,854, and 10,046,300, Buchanan et al., the contents of which are incorporated by reference herein, are formed infusing gases as ions into liquids. In these systems, such ions can be charged molecules or charged monatomic particles injected into a liquid stream. However, some applications benefit from the infusion of gas into liquid without major amounts of dissociation into monatomic ions. Thus, these systems benefit from molecular infusion or accelerated diffusion of a gas into a liquid.

For instance, in hydroponics, which is a method of growing plants without soil by using mineral nutrient solutions in a water solvent, oxygen levels of approximately 12 to 14 parts-per-million (PPM) are typically desirable. In some applications, levels as high as 50 PPM are desired. In Aquaponics, which combines conventional aquaculture, raising aquatic organisms in tanks, with hydroponics, maintaining high oxygen levels is often required for growth and good health of the species being raised.

In further applications, high levels of molecular gas infusion plus monatomic ionic injection is desired. For example, in hydroponic water treatment applications, a relatively low level of Oxidation Reduction Potential (ORP) may be desirable, such as approximately 350 to 500 mV. At the same time, high levels of dissolved oxygen in water is desirable for optimum plant health and growth.

What is needed is a simple, efficient, adjustable, low cost system and method for injecting or infusing a high level of a target gas into a liquid, whether flowing or stationary. Heretofore, there has not been a system and method for injecting particles from a gas into a liquid with the advantages of the present invention.

SUMMARY OF THE INVENTION

A first embodiment of the current invention provides a plasma laminar flow reactor comprising a housing, an electric field generator, an upper flow spreader, and a lower flow spreader. The housing may include an internal reactor chamber, a gas inlet port, and liquid inlet and liquid outlet ports. The electric field generator may include a first electrode, an optional pre-ionization electrode and a spaced apart second electrode and may generate an electric field or electric fields therebetween. The first electrode and optional pre-ionization electrode may be composed of one or more concentric shapes. A second electrode may have a shape similar to the first electrode or another shape depending on the application and the electrical nature of the liquid passing through the reactor. The second electrode may be spaced close to or spaced farther from the first electrode. In cases where the second electrode is not in close proximity to the first electrode, the second electrode may have any shape convenient to the design. Together, the first and second electrodes may produce a cylindrical electrical field close to the first electrode. The optional pre-ionization electrode may produce an electric field in close proximity to the field produced by the first electrode and second electrode. The plasma laminar flow reactor may also include a dielectric element positioned between the first electrode, the optional pre-ionization electrode, and the second electrode adjacent to the first electrode and optional pre-ionization electrode. The upper flow spreader may supply a stream of gas and liquid to the reactor chamber and may be positioned within the reactor chamber concentrically with the first electrode and the optional pre-ionization electrode. The lower flow spreader may supply a base for the stream of liquid as it flows to the reactor chamber and may be positioned within the reactor chamber concentrically with the first electrode and the upper flow spreader. The gas may create a gas zone inside the reactor chamber. The stream of liquid and the stream of gas may flow adjacent one another radially outward from the center of the reactor chamber and pass through the electric field. This may allow the gas and liquid to create and maintain two layers (gas over liquid) as the gas and liquid pass through the electric field. The gas may be injected from a relatively higher pressure gas source than the liquid through a flow limiting valve, small pump either as a steady flow or pulsed on and off, or other means well known to those familiar with gas control systems, such that the gas zone above the liquid is maintained.

A second embodiment of the current invention provides for an alteration of the second electrode by adding a dielectric isolation between the second electrode and the liquid. This may enable complete electrical isolation of the drive electronics and the liquid and gases to be used in the reactor. In addition, this may allow for plasma reactors without any conductive elements contacting the liquid.

A third embodiment of the current invention provides an alteration to the first electrode, the pre-ionization electrode, and/or the second electrode that can be used to modify the electrical characteristics of the reactor. This may enable larger reactors and more flexibility in design. In this embodiment the electrode is broken into several smaller electrodes. This may allow the plasma area to be larger without a proportional increase in the capacitance of the first electrode. This may be desirable for the voltage generator. The number of first or second electrodes may depend on the needs of the reactor and the reaction desired.

The present invention includes plasma reactor systems having a housing with an internal reaction chamber; at least one electric field generator configured for generating one or more electric fields between electrodes, with at least a portion of an electric field within the reaction chamber; a dielectric element; a gas source; a liquid source; a gas inlet path to the reaction chamber; and a liquid inlet path to the reaction chamber, where the stream of gas and stream of liquid within the reaction chamber are configured to flow adjacent one another and to pass through the electric field to produce an effluent.

Creating a plasma zone using a gas adjacent to a liquid accommodates many novel uses. These uses may include, but are not limited to, ionizing a gas and injecting the ionized particles into a liquid to create a new liquid; ionizing a gas and injecting ionized particles into a liquid to disinfect, oxidize, or otherwise modify the liquid in a desirable manner; ionizing a gas in order to dissociate molecules into their constituent atoms or different molecules in the gas to allow for undesirable atoms and/or molecules to enter a liquid and be removed from the gas stream; and ionizing a gas which modifies the molecules of the liquid in a desirable manner.

In another aspect of the present invention, a reactor system and method is configured for injecting or infusing ionized molecular particles, ionized monatomic particles, and/or non-ionized particles of a gas into a flowing or non-flowing liquid. The reactor includes a reaction chamber configured for holding a liquid and a gas adjacent to the liquid. A high intensity alternating current (AC) electric field is connected and applied to the reaction chamber, configured for making contact with the gas and/or the liquid. The voltage power level of the AC electric field is configured for adjustment as desired for optimizing desired gas particle injection, infusion, or diffusion into liquid. By varying the electrical field strength of these systems, the ratio of molecular infusion and ionic injection can be controlled. In embodiments of the present invention, the AC electric field may or may not ionize molecules in a gas or liquid and may terminate in a liquid. Moreover, the electric field may pass through a gas to be infused into a liquid while the gas is adjacent to the liquid and/or pass through the liquid. The present invention is configured for adjustment of the electric field to enhance the infusion of gas particles into liquid.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the current invention will be apparent from the following detailed description of the embodiments and the accompanying drawing figures.

