Patent Application
20090121798
1. Field of the Invention
The invention concerns industrial waste management methods that include drying waste, burning dried waste, enhancing chemical processes, fixing free nitrogen, burning waste metal, reclaiming component metals from mixed waste metal, and gasification, pyrolysis, and plasma waste disposal. The high-power, microwave energy apparatus is designed to replace the gas and electric apparatus and the methods presently employed in industrial drying, chemical and waste management facilities.
2. Discussion of Background
Waste management is the collection, transport, processing (waste treatment), recycling or disposal of waste materials in an effort to reduce their effect on human health or local aesthetics or amenity. A sub focus in recent decades has been to reduce waste materials' effect on the natural world and the environment and to recover resources from them. This invention concerns solid, liquid and gaseous waste management and their different requirements, procedures and fields of expertise. For example:
Landfill: Older or poorly managed landfills can create a number of adverse environmental impacts, including wind-blown litter, attraction of vermin and pollutants such as leachate, which can leach into and pollute groundwater and rivers. Another product of landfills containing harmful wastes is landfill gas, mostly composed of methane and carbon dioxide, which is produced as the waste breaks down anaerobically.
Characteristics of a modern landfill include methods to contain leachate, such as lining clay or plastic liners. Disposed waste should be compacted and covered to prevent attracting mice and rats and preventing wind-blown litter. Many landfills also have a landfill gas extraction system installed after closure to extract the gas generated by the decomposing waste materials. This gas is often burnt in a gas engine to generate electricity. Even flaring the gas off is a better environmental outcome than allowing it to escape to the atmosphere, as this consumes the methane, which is a far stronger greenhouse gas than carbon dioxide. Some of the gas can be tapped for use as a fuel.
Incineration: Incineration is the process of destroying waste material by burning it. Incineration is often alternatively named “Energy-from-waste” or “waste-to-energy”; this is misleading as there are other ways of recovering energy from waste that do not involve directly burning it (e.g., anaerobic digestion, pyrolysis & gasification).
Incineration is carried out on a large scale by industry. It is recognized as a practical method of disposing of hazardous waste materials, such as medical waste. Many entities now refer to disposal of waste by exposure to high temperatures as “thermal treatment” (however this also includes gasification and pyrolysis). This concept encompasses recovery of metals and energy from municipal solid waste as well as safe disposal of the remaining ash and reduction of the volume of waste.
Though classic incineration is still widely used in many areas, especially developing countries, incineration as a waste management tool is becoming controversial for several reasons. First, it may be a poor use of many waste materials because it destroys not only the raw material, but also all of the energy, water, and other natural resources used to produce it. Some energy can be reclaimed as electricity by using the combustion to create steam to drive an electrical generator, but even the best incinerator can only recover a fraction of the caloric value of fuel materials. Second, incineration of municipal solid wastes does produce significant amounts of dioxin and furan emissions to the atmosphere. Dioxins and furans are considered by many to be serious health hazards. Incineration also produces large amounts of ash requiring safe disposal so as not to contaminate underground aquifers. Until recently, safe disposal of incinerator ash was a major problem. In the mid-1990s, experiments in France and Germany used electric plasma torches to melt incinerator ash into inert glassy pebbles, valuable in concrete production. Incinerator ash has also been chemically separated into lye and other useful chemicals. This process, plasma arc waste disposal, is now operated commercially, and is used to convert existing waste and landfill into power generating gas and construction rubble. An incineration technique that avoids ash disposal problems is the incorporation of the ash in portland cement furnaces, with savings of fuel, a double benefit.
Pyrolysis & Gasification: Pyrolysis and gasification are two related forms of thermal treatment where materials are heated with high temperatures and limited oxygen. The process typically occurs in a sealed vessel under high pressure. Converting material to energy this way is more efficient than direct incineration, with more energy able to be recovered and used. Pyrolysis of solid waste converts the material into solid, liquid and gas products. The liquid oil and gas can be burnt to produce energy or refined into other products. The solid residue (char) can be further refined into products such as activated carbon. Gasification is used to convert organic materials directly into a synthetic gas (syngas) composed of carbon monoxide and hydrogen. The gas is then burnt to produce electricity and steam. Gasification is used in biomass power stations to produce renewable energy and heat.
Plasma Gasification is the gasification of matter in an oxygen-starved environment to decompose waste material into its basic molecular structure. Plasma gasification does not combust waste as incinerators do. It converts organic waste into a fuel gas that still contains all the chemical and heat energy from the waste. It converts inorganic waste into an inert vitrified glass. Plasma is considered as a 4th state of matter, the other three being gas, liquid, and solid. Electricity is fed to a torch, which has two electrodes, creating an arc. Inert gas is passed through the arc, heating the process gas to internal temperatures as high as 13,000° C. (25,000° F.). The temperature a meter from the torch can be as high as ˜4000° C. (˜8,000° F.). Because of these high temperatures the waste is completely destroyed and broken down into its basic elemental components. There are no tars or furans. At these high temperatures all metals become molten and flow out the bottom of the reactor. Inorganics such as silica, soil, concrete, glass, and gravel are vitrified into glass and flow out the bottom of the reactor. There is no ash remaining to go back to a landfill. The plasma reactor does not discriminate between types of waste. It can process any type of waste. The only variable is the amount of energy that it takes to destroy the waste. Consequently, no sorting of waste is necessary and any type of waste, other than nuclear waste, can be processed. The reactors are large and operate at a slightly negative pressure, meaning that the feed system is simplified because the gas does not want to escape. The gas has to be pulled from the reactor by the suction of the compressor. Each reactor can process 20 tons per hour compared to 3 tons per hour for typical gasifiers. Because of the size and negative pressure, the feed system can handle bundles of material up to 1 metre in size. This means that whole drums or bags of waste can be fed directly into the reactor making the system ideal for large scale production. The gas coming out of a plasma gasifier is lower in trace contaminants than with any kind of incinerator or other gasifier. Because the process starts with lower emissions out of the reactor, it is able to achieve significantly lower stack emissions. The gasifier doesn't care about the amount of moisture in the waste. The moisture consumes energy to vaporize and can impact the capacity and economics; however, it will not affect the process. Gas from the plasma reactor can be burned to produce electricity or can be synthesized into ethanol to contribute to automotive fuel.
Mechanical Biological Treatment is a technology category for combinations of mechanical sorting and biological treatment of the organic fraction of municipal waste. The “mechanical” element is usually a bulk handling mechanical sorting stage. This either removes recyclable elements from a mixed waste stream (such as metals, plastics and glass) or processes. The “biological” element refers to either anaerobic digestion or composting. Anaerobic digestion breaks down the biodegradable component of the waste to produce biogas and soil conditioner. The biogas can be used to generate renewable energy. More advanced processes such as the ArrowBio Process enable high rates of gas and green energy. This is facilitated by processing the waste in water.
It is an object of this invention to augment or replace gas and electric furnaces presently employed in the aforementioned waste disposal processes with a variable-output, high-power, microwave energy power supply.
It is an object of this invention to teach methods for using a variable-output, high-power, microwave power supply to augment or replace the gas and electric heating apparatus methods presently employed in large scale industrial yeast fermentation, drying, chemical and waste management facilities.
It is an object of this invention to utilize the teaching of my:
Assigned to The United States Department of Energy, Washington, D.C., U.S. Pat. No. 5,843,287 “Method For Recovering Metals From Waste”, by Wicks, et al, teaches a method for recovering metals from metals-containing wastes, and vitrifying the remainder of the wastes for disposal. Metals-containing wastes such as circuit boards, cathode ray tubes, vacuum tubes, transistors and so forth, are broken up and placed in a suitable container. The container is heated by microwaves to a first temperature in the range of approximately 300°-800° C. to combust organic materials in the waste, then heated further to a second temperature in the range of approximately 1,000°-1,550° C. at which temperature glass formers present in the waste will cause it to melt and vitrify. Low-melting-point metals such as tin and aluminum can be recovered after the organics combustion is substantially complete. Metals with higher melting points, such as gold, silver and copper, can be recovered from the solidified product or separated from the waste at their respective melting points. Network former-containing materials can be added at the start of the process to assist vitrification in novel combinations and configurations to reduce the overall volume of waste and convert waste into useful products.
It is an object of this invention to teach an improved microwave power supply designed to reduce the cost and increase the efficiency of existing gas and electric waste disposal processes.
It is an object of this invention to innovate a variable-output, high-power, microwave energy apparatus to augment or replace gas and electric apparatus and methods presently employed in large scale drying, yeast fermentation, chemical and waste management facilities.
It is an object of this invention to teach a high-power, microwave power supply that is removably connected to underground caves or excavations configured as microwave oven chambers to microwave waste therein.
It is an object of this invention to teach a high-power, microwave power supply designed to fit into the basement of a high rise building to burn up waste and to generate electricity from the heat emitted by the burning waste.
It is an object of this invention to teach a microwave waste management power supply designed to dry waste, burn dried waste, enhance chemical processes, fix free nitrogen, burn waste metal, reclaim component metals from mixed waste metal, and for gasification, pyrolysis, and plasma waste disposal.
A power supply for a high-power, industrial magnetron is connected directly to a conventional public service 4,160 volt and higher power line. A variable capacitor provides wattless, variable power control to the industrial magnetron. The microwave output of the high-power, industrial magnetron is removably attached to a series of tractor trailers or train boxcars each configured as a microwave work chamber. Individual tractor trailer or train boxcar chambers are designed to enhance 1) drying waste material, 2) burning waste metal, 3) reclaiming component metals from mixed waste metals, 4) gasification, pyrolysis, and plasma waste disposal 5) enhancing chemical processes or 6) fixing free nitrogen. The high-power, microwave power supply is taught removably connected to underground caves or excavations configured as microwave oven chambers to microwave waste therein. The high-power, microwave power supply is taught located in the basement of a high rise building, powered from an underground high-voltage, public utility electric service. The basement microwave power supply is designed to burn up the high rise building's waste and to generate electricity from the heat emitted by the burning waste.
The advantages and benefits resulting from the described high-power microwave power supply will become apparent from the following detailed description by reference to the accompanying drawings in which:
My U.S. Pat. No. 3,792,369 “Variable Reactance Controls For Ac Powered Heating Magnetrons” teaches a power supply for a high-power, industrial magnetron in which a variable capacitor provides wattless, variable power control. U.S. Pat. No. 3,792,369 teaches, in industrial, microwave applications, a power supply that operates without the need for a massive, bulky, space-consuming, public-utility, high-power, high-voltage step-down transformer and without the need for a massive, bulky, space-consuming, high-power, high-voltage step-up transformer to power a high-power magnetron. My U.S. Pat. No. 3,792,369 teaches that when a variable capacitance, high-power magnetron power supply is connected between a conventional public service power line, 4,160 volts and higher, and ground. There are substantial cost savings by obviating 1) the 7-10% operating losses inherent in a public utility high-power, high-voltage step-down transformer, 2) the 7-10% operating losses inherent in the presently employed high-power, high-voltage step-up magnetron transformer, 3) the cost of these two massive transformers and 4) their requirement for valuable industrial space.
In a preferred embodiment, in
In
High voltage tower 22 attaches to and supports remotely controlled mechanism means 18. Mechanism means 18 operates movable lower plate 17 of variable capacitor 15. When variable capacitors 5's lower plate 17 is at its farthest position from variable capacitor 15's fixed upper plate 16 magnetron 1 is turned off. Hinge 19, mounted on high voltage tower 22, and is attached to end 20 of lower plate 17 of variable high voltage capacitor 15. Wire 21 connects high voltage capacitor 15's lower plate 17 to the plate of diode 6 and magnetron 1's cathode 25. In operation, magnetron 1's output feeds a horn antenna 26 that terminates in microwave energy output connector 28.
My U.S. Pat. No. 3,569,657 “Methods Of Processing And Transporting Articles” teaches that a microwave heating chamber and a microwave generator can exist independently and can be removably attached. One microwave generator can be used to microwave material located in a series of tractor trailers, train boxcars and the like configured as microwave heating chambers. In operation, waste material is loaded into a reusable or disposable tractor trailer or train boxcar microwave oven, driven to a microwave generator facility, individually microwaved and then, while cooling, delivered to a dump site. This type operation obviates the need to first load a tractor trailer or train boxcar with waste material, drive it to the microwave generator facility, there unload the tractor trailer or train boxcar and transfer the waste material into a dedicated microwave oven chamber, expose the waste material to microwave energy, unload the microwaved waste from the dedicated microwave oven chamber and load the microwaved waste back into a tractor trailer or train boxcar for subsequent delivery to a dump site.
In
In
Filament supply 5 is exposed to the same high voltage as magnetron 1's cathode and would normally require an expensive, high-voltage, space-consuming, magnetron filament transformer. In
It should be appreciated that the heat energy generated from microwaving waste has two parts 1) the heat evolved by the microwaving waste, per se, and 2) the microwave energy that turned into heat to ignite and “supercombust” (infra) the waste. When microwaving waste is employed to power an electric generator, the microwave energy is not lost it combines with the heat output of the burning waste to power the electric generator. In effect much of the microwaving energy expended burning waste is recycled back into the electric power source that powers the microwave power supply.
Because said magnetron power supply is designed to heat large loads, waveguides, circulators, field stirrers and the like are not required. Microwave arcing, spot, end and selected heating of solid waste hasten the ignition of waste material. Microwave arcing, spot, end and selected heating are not a factor when microwaving liquid waste.
To permit a public utility electric service to accommodate the turning off and on of a megawatt microwave power supply, in operation, the magnetron's high wattage output is turned on at low and slowly adjusted to maximum and, when it is time to turn off the magnetron power apparatus the variable capacitor is slowly adjusted to minimum microwave output. Note, power expended in the variable capacitor is wattless power and its capacitance adds capacitance to public utility power lines and usefully balances out some of the undesirable high inductive reactance normally present on public utility power lines.
It is expected that operators of mechanical biological treatment facilities, which rely on anaerobic digestion to break down the biodegradable component of waste to produce biogas and soil conditioner, will rely on the variable power aspect of the variable-output, high-power, microwave energy apparatus taught herein. Operators of biological treatment facilities will heat and hold a biomass at a temperature that is just below the kill temperature of the active organisms in the biomass to speed the active organisms' digestion. While waste disposal has been emphasized, the variable-output, high-power, microwave energy apparatus taught herein is useful in commercial industrial processes. For example, in the bread industry to proof bread and in the beer industry to ferment malt. The variable-output, high-power, microwave energy apparatus taught herein is useful to speed yeast's fermentation by heating and holding yeast mixtures at a temperature that is just below the kill temperature of the yeast. Microwave energy is more useful than gas and electric heating to heat and hold at a given temperature a large batch of fermenting yeast. This is because microwave energy heats in depth three dimensionally. In contrast, gas and electric heating heats a large batch of fermenting yeast from exposed, heated surfaces. Unlike microwave heating, when high-power gas or electric heat is employed to evenly heat and hold at a selected temperature a large batch of fermenting yeast, the yeast, directly in contact with gas and electric heated surfaces, are killed.
The variable-output, high-power, microwave energy apparatus taught herein is useful to increase the heat output of a burning fuel. A burning fuel exposed to microwave energy “supercombusts.” “Supercombustion” is a term I coined, in 1965, to describe the operation of my U.S. Pat. No. 3,469,053, a “Microwave Kiln.” When I microwaved pure charcoal, it ignited and unexpectedly burned fiercely. I microwaved better fuels as wood, coal and the like until they ignited and not only burned fiercely they would “supercombust.” Continued application of microwave energy resulted in plasma discharges that looked and sounded like lightening flashes. “Supercombusting” fuel burns up and is consumed more rapidly than a burning fuel not exposed to microwave energy. When “supercombustion” is used to boil water to power an electric generator, the high burning temperature and high caloric output of “supercombusting” fuel results in cost savings. Additionally, the microwave energy that turned into the heat energy required to “supercombust” ads to the heat energy expended by the burning fuel used to boil water to power an electric generator and, in effect, microwave energy is recycled.
Although this invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that numerous changes in details of construction and arrangement of parts may be resorted to without departing from the spirit and scope of the invention.
