Patent Application
20180216020
Gasifiers described herein may be used to treat waste and generate energy from that waste treatment. Certain gasifiers disclosed herein may have improved energy efficiency and produce cleaner syngas than prior gasifiers. Under appropriate conditions, the gasifiers may eliminate undesired waste while at the same time delivering a significant net energy benefit to the operator of the gasifier.
Gasifier 100 as depicted in the figures is substantially cylindrical and contains two chambers, namely Arc plasma chamber 110 and Microwave plasma chamber 200. Arc plasma chamber 110 is substantially enclosed having an Arc plasma chamber floor 113 with a Chamber drain 116 and Internal orifice 203 at the top of Arc plasma chamber 110. Arc plasma chamber 110 is substantially lined with Refractory 130. Three Arc plasma torches 120 are equally spaced around the circumference of Arc plasma chamber 110 below the three Feed conveyors 140 such that Feed conveyors 140 drop feed material into the path of Arc plasma torches 120. There may be three or more Feed conveyors 140 and the number of feed conveyors may be equal to the number of the arc plasma torches. Microwave plasma chamber 200 is located above Arc plasma chamber 110 and separated from Arc plasma chamber 110 by Internal orifice 203 and Chamber separation wall 206. Chamber separation wall 206 may be a cooled dividing wall and may in particular be a liquid cooled dividing wall. Microwave plasma chamber 200 is also lined with Refractory 130 and is surrounded by three Microwave sources 210 and three Steam injection holes 230 all around the circumference of Microwave plasma chamber 200. Steam pipes 233 feed steam to Microwave plasma chamber 200 through Steam injection holes 230. Gasifier 100 is depicted as being jacketed with Inner steel wall 240 being adjacent to Refractory 130 and Coolant jacket 246 is located between Inner steel wall 240 and Outer steel wall 243. Gas exit 260 is located at the top of Microwave plasma chamber 200. Gas exit 260 may be designed as a heat exchange unit to recover heat from the gases exiting Microwave plasma chamber 200. The heat exchange unit may be designed to bring the temperature of the gas exiting Gasifier 100 down to a temperature between the temperature that would lead to condensation in the heat exchange unit and below the plasma/gas temperature threshold. The initial heat exchange unit may be designed for quick cooling such that the gas temperature leaving the initial heat exchange unit may for example be between 700 and 800° C.
The distance between Arc plasma chamber bottom height 410 and Arc plasma torch height 413 may be 300 mm. The distance between Arc plasma torch height 413 and Feed conveyor height 416 may be 300 mm. The distance between Feed conveyor height 416 and Internal orifice height 418 may be 240 mm. The distance between Internal orifice height 418 and Microwave source height 420 may be 285 mm. The distance between Microwave source height 420 and Microwave plasma chamber top height 423 may be 600 mm. The external diameter of Gasifier 100 may be 1000 mm.
As that phrase is used herein, “microwave plane” is the plane that is perpendicular to the flow of gas through Microwave plasma chamber 200 or the second chamber and that most nearly encompasses all of the microwave sources. Further the phrase “microwave cross-sectional area,” as used herein, is the area within Microwave plasma chamber 200 or the second chamber that is part of the microwave plane. Further the phrase “microwave center,” as used herein, is the point representing the centroid of the microwave cross-sectional area. The phrase “cross-sectional distance,” as used herein, is the length of the shortest line segment fully crossing the microwave cross-sectional area that also passes through the microwave center. By way of example, the cross-sectional distance of the Gasifier 100 as depicted in
The distance between the chamber drain and the gas exit may be characterized as the “reactor length.” The reactor length divided by the cross-sectional distance may be characterized as the “gasifier aspect ratio.” The gasifier aspect ratio may, for example, be 2.0 with certain examples falling between 0.8 and 6.0 and a significant number of those examples falling between 1.4 and 4.0.
Gasifier 100 may further be described in terms of the vertical alignment of components. From the bottom of Gasifier 100 to the top of Gasifier 100, Arc plasma chamber bottom height 410 is situated below Arc plasma torch height 413 which is situated below Feed conveyor height 416 which is situated below Internal orifice height 418 which is situated below Microwave source height 420 which is situated below Microwave plasma chamber top height 423. In cases in which components are not in complete alignment, Arc plasma torch height 413 represents the average height of the centers of the individual arc plasma torches located within Arc plasma chamber 110. Similarly, Feed conveyor height 416 represents the average height of the centers of the individual feed conveyors located within Arc plasma chamber 110 and Microwave source height 420 represents the average height of the centers of the individual Microwave sources 210 located within Microwave plasma chamber 200. In the embodiment depicted in
As that phrase is used herein “microwave chamber height” represents the distance between Microwave plasma chamber top height 423 and Internal orifice height 418. As that phrase is used herein “microwave chamber aspect ratio” represents the microwave chamber height divided by the cross-sectional distance. The microwave chamber aspect ratio may, for example, be 1.0 with certain examples falling between 0.3 and 3.0 and a significant number of those examples falling between 0.7 and 2.0. As that phrase is used herein “arc plasma chamber height” represents the distance between Internal orifice height 418 and Arc plasma chamber bottom height 410. As that phrase is used herein “arc plasma aspect ratio” represents the microwave chamber height divided by the cross-sectional distance. The arc plasma aspect ratio may, for example, be 1.0 with certain examples falling between 0.3 and 3.0 and a significant number of those examples falling between 0.7 and 2.0. As that phrase is used herein the “chamber volume proportion” represents the microwave chamber volume divided by the arc plasma chamber volume. The chamber volume proportion may, for example, be 1.0 with certain examples falling between 0.3 and 3.0 and a significant number of those examples falling between 0.7 and 2.0.
As that phrase is used herein “orifice area proportion” represents the orifice cross sectional area divided by the microwave cross-sectional area. The orifice diameter proportion may, for example, be 0.017 with certain examples falling between 0.004 and 0.068 and a significant number of those examples falling between 0.011 and 0.043. As that phrase is used herein the “exhaust area proportion” represents the cross-sectional area of the gas exit divided by the microwave cross-sectional area. The exhaust area proportion may, for example, be 0.25 with certain examples falling between 0.05 and 0.70 and a significant number of those examples falling between 0.15 and 0.50.
The above-described embodiments have a number of independently useful individual features that have particular utility when used in combination with one another including combinations of features from embodiments described separately. There are, of course, other alternate embodiments which are obvious from the foregoing descriptions, which are intended to be included within the scope of the present application.
