Chemistry: electrical and wave energy – Processes and products – Processes of treating materials by wave energy
Reexamination Certificate
2001-07-03
2003-06-03
Wong, Edna (Department: 1753)
Chemistry: electrical and wave energy
Processes and products
Processes of treating materials by wave energy
C204S157300, C204S158200
Reexamination Certificate
active
06572737
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to a device and process for thermal treatment of waste gases and reactive gases. The invention is used for the destruction and reduction of pollutants from effluent waste streams, and to produce gaseous products from reactant gases.
2. Prior Art
Devices, which operate on electricity to thermally treat gases from waste streams to reduce pollution and thermally react gases for synthesis of products, do not rely on natural gas for supplying energy. Devices that use natural gas to produce energy for such applications create carbon dioxide, carbon monoxide and nitrogen oxides from the energy source. Electricity is considered to have cleaner operation when used in such devices since the above chemical species are not produced during operation from the heat source. Electric devices for pollution control applications produce less pollution at the point source when compared to the counter technologies operating on natural gas. The reduced pollution is favorable to reduce greenhouse gases and to the meet the requirements of the Clean Air Act of 1990. There are many types of electric heating methods; this discussion will focus on designs used to produce heat and reaction with applied electromagnetic energy.
The scope of this current invention is a device for thermal treatment of gases and pollutants that employs 1) alternate cavity and susceptor geometries for providing more homogeneous interactions of applied electromagnetic energy in the volume of the susceptor regardless of the flow rate and diameter of the exhaust duct width, 2) heat transfer methods to improve the overall heat efficiency of the device, 3) a susceptor structure that has reflectivity as principle mode of interaction with applied electromagnetic energy, which allows for energy to penetrate a susceptor, 4) composite susceptor materials, 5) a simple method of controlling the temperature versus energy concentration in the susceptor, and 6) field concentrators to concentrate the energy density of the applied electromagnetic energy.
Cavity geometries in these devices affect the optical properties of the electromagnetic energy within the susceptor. Electromagnetic energy, whether ultraviolet, infrared, microwave or radio frequencies, exhibits the same optical properties as the visible spectrum when interacting with geometric shapes and surfaces that are similar to a lens. The electromagnetic energy in a susceptor can either converge or diverge due to the geometric shape of the susceptor following the same principles as optical lenses. Additionally, the modes of propagation of the electromagnetic energy are dependent upon the cavities geometry. These modes effect the distribution of electromagnetic energy in the cavity. These modes are different for cylindrical and rectangular cavities (see, e.g,
Handbook of Microwave Engineering
).
Electromagnetic energy that is incident perpendicular to the perimeter of the circular cross-section of a cylindrical susceptor will converge initially, concentrating the energy within the cross-section. This concentration will cause the material inside the susceptor to absorb more energy than the material near the surface, changing the dielectric properties of the material inside the cross-section. This concentration of energy can make the material, which is located in the susceptor's interior, between the center and the perimeter, to absorb more energy, thereby reducing the depth of penetration of the material due to the susceptor's geometry.
The optical properties of rectangular cavities and planar surfaces are different. Rectangular cavities with a susceptor having a rectangular geometry and planar surfaces will follow the optical properties of a flat surface. A flat surface does not concentrate or disperse energy as do curved surfaces, such as convex and concave surfaces. With a flat surface of incidence for applied electromagnetic energy, the absorption of electromagnetic energy in a susceptor is due only to the properties of the materials and is not influenced by energy, which is concentrated by curved geometries. Incident energy on susceptors with flat surfaces will not be concentrated within a structure with homogeneous material, and the depth of penetration will be influenced by the incident energy's power, the electric fields and magnetic fields inside the susceptor. Conversely, incident energy on susceptors with curved geometry can be concentrated within a susceptor with homogeneous materials, and the depth of penetration of the energy will be influenced by the ability of the curved surface to concentrate energy inside the susceptor.
The overall energy efficiency of such devices for thermal treatment of gases can be improved with a better heat transfer process to capture the energy that is lost from cooling the tube that is the source for the applied electromagnetic energy. In industrial microwave drying operations, the heat produced from cooling the magnetrons with air is applied to the articles that are being dried with the microwaves. This synergistic drying, which uses hot air and microwaves, increases the energy efficiency of the drying process.
Alternative composite materials and susceptor structures can be used to facilitate the thermal treatment of gases. These composite materials and susceptor structures are known as artificial dielectrics.
Artificial dielectric structures date back to the 1940s. Artificial dielectrics were used as lenses to focus radio waves for communication (Koch). Artificial dielectrics use conductive metal plates, rods, spheres and discs (second phase material) which are embedded in matrices of low dielectric constants and low dielectric losses to increase the index of refraction, thus reducing size of a lens to achieve the desired optical properties. The second phase material reflects the energy and uses diffuse reflection to transmit electromagnetic energy. These plates, rods, spheres, and discs can be arranged in a lattice structure to produce an isotropic or an anisotropic structure.
When conductive elements are embedded in a low dielectric constant and low dielectric loss matrix, the effect of these on the matrix material's dielectric loss factor is negligible and the dielectric constant of the composite lens is increased. However, these above effects are limited and influenced by the size, shape, conductivity and volume fraction of the material embedded in a matrix of low dielectric loss, low dielectric constant of the material as well as the wavelength of the incident radiation. The dielectric strength and complex dielectric constant of the matrix material plays important additional roles in the design of artificial dielectric lenses. On the other hand, selection of matrix materials with different dielectric properties and incorporation of second phase materials such as semiconductors, ferroelectrics, ferromagnetics, antiferroelectrics, antiferromagnetics, dielectrics with higher dielectric losses, and dielectrics with conductive losses that produce absorption of microwave energy, produce heat in an artificial dielectric.
Lossy artificial dielectrics were demonstrated by the 1950s and subsequently used at the microwave frequencies to sinter ceramic articles, in food packaging for heating foodstuffs, in browning apparatuses for foodstuffs, in consumer products, and to render adhesives flowable for bonding applications.
The structure of the artificial dielectrics determines the electromagnetic properties. When the volume fraction of the second phase materials inside the artificial dielectric reaches a certain level, the artificial dielectric will reflect incident electromagnetic energy, shielding the artificial dielectric from absorbing electromagnetic energy. The volume fraction of the second phase material at which the artificial dielectric shields electromagnetic energy is dependent on the second phase material's reflectivity, the shape of the second phase material, and the temperature. By controlling the amount of reflection, the susceptor's r
Technoprop Colton LLC
Wong Edna
LandOfFree
Heat transfer with artificial dielectric device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Heat transfer with artificial dielectric device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Heat transfer with artificial dielectric device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3137423