Abstract:
The system includes a source of solid, liquid or sludge waste and a source of waste gas. A waste conversion device receives the solid, liquid or sludge waste and converts it into a hydrogen-rich gas. An internal combustion engine receives as fuel the hydrogen-rich gas and the waste gas and burns them to produce mechanical work. A generator is operatively connected to the internal combustion engine to generate electricity. Some of the generated electricity may be used to power the waste conversion device. The system allows for high-efficiency, lean-burn operation while reducing the amount of waste converted to hydrogen-rich gas.
Abstract:
One or more auxiliary plasma torches are provided to a waste processing plant at strategic locations within the chamber and directed towards the waste column. When a bridge forms within the chamber the auxiliary plasma torches may be operated such as to provide an additional heat source where needed, quickly heating the organic solids, which thus pass through the bituminsation and charcoal formation stages quickly. The additional heat source may be in the neighborhood of the bridge, but may also be near the bottom end of the chamber, in which case the additional temperature at the bottom of the chamber effectively moves the combustion and gasification zones for the charcoal to a higher part of the chamber, altering the temperature profile. The heat source also enables the inorganic wastes to be heated rapidly to pass beyond the melting stage relatively quickly. The debridging process may be further enhanced by providing secondary plasma torches at various levels upwards of the primary torches, the secondary torches at any level being operated as and when needed to achieve the desired effect.
Abstract:
A liquid waste feeding system having a liquid inlet to a plasma torch based waste processing chamber, disposed intermediate the primary plasma torch arrangement at the bottom end of the chamber and the top gas products outlet. the liquid inlet is positioned within the chamber such that liquid waste flowing from the inlet into the chamber is directed at a high temperature zone of waste column, and the liquid inlet is typically associated with a hot gas jet means. The hot gas jet means that provides the required high temperature zone may comprise one or more secondary plasma torches configured to provide hot gas jets into the liquid discharge zone of the inlet Alternatively, the hot gas jet may be provided by the primary plasma torches, in which case the liquid inlet is disposed within a predetermined area close to and above at least one of the primary plasma torches.
Abstract:
A plasma arc torch that is capable of operating in a non-transferred arc mode and a transferred arc mode, and that is intended for use for use with a plasma arc treatment system. The plasma arc torch includes an electrode, a plasma gas ring and a nozzle. At least one power supply within the plasma arc treatment system is connected to the electrode, the nozzle and a workpiece. While the torch operates in a non-transferred arc mode, the non-transferred arc heats gas supplied by the plasma gas ring to create plasma gas that heats the workpiece to raise its conductivity. Once the workpiece is at an appropriately conductive level, the arc is automatically transferred since the ground point can now be found.
Abstract:
A preferred waste treatment system and method employs multiple reactor zones for processing heterogeneous waste. In one embodiment, the reactor system (10) includes the following components: first (12) and second (14) solid waste feed subsystems; a liquid waste feed subsystem (16); a plasma torch or gas burner (18) for heating a preliminary vitrification chamber (20) of the reactor system (10); a joule effect heater (22) for heating a vitrification chamber (24); a gaseous effluent processing subsystem (26); first (30) and second (32) slag discharge processing subsystems; and a bulk processing unit (400), including a loading and/or cooling area (406), a waste destruction chamber (408) heated to temperatures between about 250° F. and 2100° F.; a conveying mechanism (418) between the loading area (406) and the waste destruction chamber (408). In an alternative embodiment, each of the reactor zones is heated by joule effect heaters. The reactor system (10) can be operated in an oxidation or reduction mode. In either mode, the reactor system (10) allows for more complete reaction of a variety of heterogeneous waste.
Abstract:
A facility for reclaiming useful products from solid municipal and hazardous waste uses a rotary kiln to convert the material into a stream of inorganic ash and a stream of gaseous combustion products. The stream of combustion products passes in heat exchange relation to unburned waste and produces a stream of volatile carbon compounds which are deficient in oxygen. The streams of combustion products and volatile carbon compounds are converted in a plasma arc generator into a stream of hot, disassociated atoms. The stream of hot gas is cooled by passage through one or more heat exchangers that reclaim process heat. The stable compounds that are produced are hydrogen and carbon monoxide. The process is controlled by monitoring carbon dioxide in the carbon monoxide stream. The carbon monoxide and hydrogen may be used separately or combined, as in a methanol synthesis plant.
Abstract:
Methods and apparatus for high efficiency generation of electricity and low oxides of nitrogen (NO.sub.x) emissions are provided. The electricity is generated from combustion of hydrogen-rich gases produced in waste conversion units using ultra lean fuel to air ratios in the range of 0.4-0.7 relative to stoichiometric operation in internal combustion engine-generators or ultra lean operation in gas turbines to ensure minimal production of pollutants such as NO.sub.x. The ultra lean operation also increases the efficiency of the internal combustion engine. High compression ratios (r=12 to 15) can also be employed to further increase the efficiency of the internal combustion engine. Supplemental fuel, such as natural gas or diesel oil, may be added directly to the internal combustion engine-generator or gas turbine for combustion with the hydrogen-rich gases produced in waste conversion unit. In addition, supplemental fuel may be reformed into a hydrogen-rich gas in a plasma fuel converter and then introduced into the internal combustion engine-generator or a gas turbine for combustion along with supplemental fuel and the hydrogen-rich gases produced in waste conversion unit. The preferred embodiment of the waste conversion unit is a fully integrated tunable arc plasma-joule heated melter with a common molten pool and power supply circuits which can be operated simultaneously without detrimental interaction with one another. In this embodiment, the joule heated melter is capable of maintaining the material in a molten state with sufficient electrical conductivity to allow rapid restart of a transferred arc plasma.
Abstract:
A method and apparatus for heat treating of hazardous waste by heating the waste in a pyrolyzing chamber and forming an off-gas, heating the off-gas for a sufficient time to destroy dioxins and furans, then reducing and cooling the off-gas in a secondary treating chamber having a graphite stack and recovering metallics by distillation.
Abstract:
Methods and apparatus for treating waste are provided. Waste is converted in an arc plasma-joule heated melter system utilizing one or more arc plasma electrodes and a plurality of joule heating electrodes. The arc plasma electrode(s) can be configured for operation utilizing AC or DC power, or for switching between AC and DC power. The arc plasma electrodes can also be configured for independent arc voltage and arc current control. The joule heating circuits are configured for simultaneous operation with the arcing electrodes, but without detrimental interaction with the arcing electrodes. The systems provide stable, non-leachable products and a gaseous fuel. The gaseous fuel can be utilized in a combustion or non-combustion process to generate electricity.
Abstract:
The present invention provides a relatively compact self-powered, tunable waste conversion system and apparatus which has the advantage of highly robust operation which provides complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards. The system provides the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or by an internal combustion engine. The solid product can be suitable for various commercial applications. Alternatively, the solid product stream, which is a safe, stable material, may be disposed of without special considerations as hazardous material. In a preferred embodiment of the invention, the arc plasma furnace and joule heated melter are formed as a fully integrated unit with a common melt pool having circuit arrangements for the simultaneous independently controllable operation of both the arc plasma and the joule heated portions of the unit without interference with one another. The apparatus may additionally be employed with reduced or without further use of the gases generated by the conversion process. The apparatus may be employed as a self-powered or net electricity producing unit where use of an auxiliary fuel provides the required level of electricity production.