1. Field of the Invention
The present invention is a device for separating unburned carbon in fly ash and a separation method for the same. In particular, the present invention pertains to a device which lowers unburned carbon content in aggregated fly ash particles by separating the particles, and refining the particles into smaller sizes for later use.
2. Description of the Related Art
Referring now to FIG. 4, in a coal fired power plant (not shown), coal is pulverized in a pulverizing device 40 to an average particle size of roughly 15-40 micrometers (xcexcm). The coal is then mixed with air at an entrance to a boiler (not shown), where it is burned inside a combustion chamber 41 linked to pulverization device 40. In addition to the carbon content in the coal (fuel), there is approximately 5-30 weight % of ash material. Typically, the ash material is not burned in the above process but is discharged as an undesirable waste product called coal ash at multiple process positions, as will be described.
The components of the discharged coal ash are approximately 40-60 weight % silicon oxide, 20-30 weight % aluminum oxide (alumina oxide), 5-10 weight % calcium oxide, 3-8 weight % iron oxide, 2-10 weight % unburned carbon, and other minor particles. Depending on the origin of the coal used, the discharged coal ash may be alternatively classified as clinker ash, cinder ash, or fly ash. The components of each substance vary slightly due to original composition and processing.
Clinker ash is collected from a boiler furnace bottom part 42 positioned below combustion chamber 41, and is typified as a solid glass-type material. The clinker ash is thereafter pulverized and discharged in a conveniently handled size of approximately 0.5-1 millimeters (mm) (500-1000 xcexcm). Clinker ash comprises approximately 10-20% of the ash or coal ash waste.
Cinder ash is ash that falls into a fuel economizer 43 positioned down-process from combustion chamber 41. The cinder ash is collected as spherical particles having an average particle size of 30-70 micrometers (xcexcm) or as aggregates of these spherical particles. Cinder ash comprises approximately 5% of the ash.
Fly ash is ash collected in an electric precipitator 44 positioned down-process from fuel economizer 43. Fly ash is collected as spherical particles of average particle size 10-30 micrometers (xcexcm) or as aggregates of the spherical particles. Fly ash comprises approximately 70-80% of the ash.
Cinder ash and fly ash, are liquefied in air during formation by the heat of combustion, and thereafter cool to form typically spherical particles. These typically spherical particles of cinder ash and fly ash, have an average particle size of 10-70 micrometers (xcexcm) or may form as aggregates of these particles.
It should be understood from the above, that unburned carbon typically adheres to the pseudo-spherical particles of the ash component or is mixed in independently.
Unfortunately, a large amount of fly ash is discharged as undesirable waste in landfills increasing costs, consuming space, and forming industrial waste.
Even where fly ash with a high unburned carbon content is later used as a clay substitute material in cement, there is a limit to the amount that can be consumed in this manner. Ultimately, a large amount of fly ash must still be disposed of in landfills. Fly ash with low unburned carbon content and small particle size may be used as an admixture for ready-mixed concrete, also within a useful limit. In sum, while there are some uses for the fly ash, the demand is insufficient for the supply and undesirable waste results.
Even if new uses are developed, the particle size, color, and particularly the residual carbon amount and the variability of each of these items make their uniform efficient utilization both difficult and costly. Due to these variabilities, it is difficult to develop new uses for fly ash as a raw material. In sum, it is essential to reduce the unburned carbon content to a preferable and controllable range and so use the fly ash as a new raw material.
Many methods have been attempted to classify the unburned carbon content of ash, including, sieve classification, electrostatic classification, wet classification, vibration classification, jet mill classification. Each has an advantage and a disadvantage but none has been used in common practice or with great success.
Among these methods, a jet mill (or fluid energy mill), in which classification is conducted after fly ash particles collide with each other and pulverized, has been gathering interest. Unfortunately, jet mills have multiple problems. These problems include complex construction, difficult maintenance, and high costs, and difficulty in simple classification, each serving as a barrier to implementation.
It is an object of the present invention to overcome the concerns listed above in a useful and inexpensive manner.
It is another object of the present invention to provide a separation device for unburned carbon that has a simple construction and can easily and effectively separate and remove unburned carbon in fly ash.
It is another object of the present invention to provide a separation method employing the device.
It is another object of the present invention to provide an unburned carbon separation device and a separation method in which abrasion on the apparatus is minimized, powder classification can be easily adjusted according to an input powder, and maintenance is easy and inexpensive.
Briefly stated the present invention is a separation device which includes a casing and a first and a second rotation blade. A pulverization chamber is defined between the casing, the first, and the second rotation blade. Operating a suction device and the first and the second rotation blades, creates channeling vortices within the pulverization chamber. Fly ash containing unburned carbon is fed into the pulverization chamber, and through repeated self-collision, unburned carbon is segregated and reduced in size while remaining particular matter is similarly segregated and reduced in size. A method employs the device and provides simple separation and segregation.
According to the present invention there is provided a separation device, comprising: a casing, the casing includes an inlet for receiving a first material containing at least an unburned carbon portion into the casing, first means for separating the first material into the unburned carbon portion and a second portion, the first means includes second means for reducing in size the unburned carbon portion into a first reduced-size portion and the second portion into a second reduced-size portion, the first means in the casing, and segregation means for receiving the first reduced-size portion and the second reduced-size portion from the casing and segregating the first reduced-size portion from the second reduced-size portion for later use whereby the separation device operates economically and effectively.
It is to be understood, that untreated fly ash is mainly, but not solely, a mixture of silicon oxide particles, aluminum oxide particles, and unburned carbon particles.
According to another embodiment of the present invention, there is provided a separation device, comprising: at least one of the first means, the second means and the segregation means being adjustable according to at least one of a size, a density, and an unburned carbon content of the first material whereby the separation device operates economically and accommodates material variation in the first material.
According to another embodiment of the present invention, there is provided a separation device, comprising: a first rotation blade in the first means, the first rotation blade having a first rotation axis, a second rotation blade in the first means, the second rotation blade having a second rotation axis, the first rotation blade opposing the second rotation blade in the casing along a common axis of rotation, and a pulverization chamber defined between the casing and the first rotation blade and the second rotation blade.
According to another embodiment of the present invention, there is provided a separation device, wherein: the pulverization chamber includes a first width defined as a separation between the first rotation blade and the second rotation blade, and the first width being adjustable according to at least the size, the density, and the unburned carbon content of the first material, whereby the separation device is adaptable according to variations in the first material.
According to another embodiment of the present invention, there is provided a separation device, wherein: the first rotation blade includes a blade quantity and a first shape adapted to an inside surface of the casing, the second rotation blade includes a blade quantity and a second shape adapted to the inside surface of the casing, at least one of the first rotation blade and the second rotation blade being rotationally operable at least one of an opposite direction and a same direction of at least the other of the first rotation blade and the second rotation blade, and the first rotation blade and the second rotation blade being rotationally operable according to the inside surface to create circulating vortices within the casing sufficient to cause the separation and the reduction in size of the first material by fracture impact and shear stress.
According to another embodiment of the present invention, there is provided a separation device, further comprising: a suction device, a connecting channel connects the suction device to the casing, and the suction device drawing gas into the inlet, over the first rotation blade, into the pulverization chamber, and over the second rotation blade to the segregation means to assist the vortices to transport the first material into the separation device for processing.
According to another embodiment of the present invention, there is provided a separation device, further comprising: at least one of a first and a second outlet opening on the casing, and the at least one outlet opening receiving the first reduced-size portion and the second reduced-size portion from the casing and transferring the first reduced-size portion and the second reduced-size portion to the segregation means.
According to another embodiment of the present invention, there is provided a separation device, further comprising: a first storage part in the segregation means, a second storage part in the segregation means, the first storage part formed for receiving and segregating the first reduced-size portion depending upon a particle size and a mass of the first reduced-size portion, and the second storage part formed for receiving and segregating the second reduced-size portion depending upon a particle size and a mass of the second reduced size-portion, whereby the separation device provides easy separation of the unburned carbon from the second portion.
According to another embodiment of the present invention, there is provided a separation device, further comprising: the first and the second outlet opening, the first outlet opening at a first position on the casing adjacent the first rotation axis receives the first reduced-size portion, and the second outlet opening at a second position on the casing adjacent an outer circumference of the second rotation blade receives the second reduced-size portion, whereby segregation of particle size and mass is simplified.
According to another embodiment of the present invention, there is provided a separation device, wherein: the first inlet opening is at a third position on the casing adjacent an outer circumference of the first rotation blade.
According to another embodiment of the present invention, there is provided a separation device, further comprising: a classification device in the segregation means, the connecting channel connects the classification device to the casing, and the classification device receives discharged particles of the first reduced-size portion and the second reduced-size portion and uses differences in mass and density of the discharged particles to classify them for later use.
According to another embodiment of the present invention, there is provided a method for separating unburned carbon in a first material containing both an unburned carbon portion and a second portion, comprising the steps of: forming a pulverization chamber between a bounding casing and a first and a second rotation blade, the first and the second rotation blades disposed on opposing sides of the pulverization chamber along a common rotational centerline, rotating at least one of the first and the second rotation blades about the common rotational centerline sufficient to create colliding vortices within the pulverization chamber and the bounding casing, supplying the first material as particles into the bounding casing from a first position on the bounding casing and the unburned carbon portion having a first specific gravity lower than a second specific gravity of the second portion, separating the first material into the unburned carbon portion and the second portion through at least one of a first process of self-collision with other first material particles and a second process of equipment-collision with the bounding casing and the first and the second rotation blades, reducing in size the unburned carbon portion and the second portion through repeated the at least on process, and segregating the reduced in size unburned carbon portion from the reduced in size second portion, whereby the method for separating operates effectively with increased speed and efficiency.
According to another embodiment of the present invention, there is provided a method for separating unburned carbon in a first material containing both an unburned carbon portion and a second portion, further comprising the steps of: receiving the reduced in size and the segregated unburned carbon portion in a first discharge opening on the bounding casing, and receiving the reduced in size and segregated second portion in a second discharge opening on the bounding casing, whereby the first material is efficiently and simply pulverized, reduced in size, and segregated for later use.
According to another embodiment of the present invention, there is provided a method for separating unburned carbon in a first material containing both an unburned carbon portion and a second portion, wherein: the first position on the bounding casing surface is adjacent an outer circumference of the first rotation blade, the first discharge opening is adjacent a rotation center axis of the second rotation blade, whereby the unburned carbon particles having lower centrifugal force than the second portion are easier to separate, and the second discharge opening on the casing is adjacent an outer perimeter portion of the second rotation blade, where the second portion having a higher centrifugal force that the unburned carbon portion are easier to separate.
According to another embodiment of the present invention, there is provided a method for separating unburned carbon in a first material containing both an unburned carbon portion and a second portion, comprising the steps of: forming a pulverization chamber between a first rotation blade and a second rotation blade disposed in an opposing manner along a single rotational axis, supplying the first material in particulate form to the pulverization chamber of a first side adjacent the first rotation blade, operating at least one of the first rotation blade and the second rotation blade along the single rotational axis and providing colliding air vortices within the pulverization chamber, colliding particles of the first material on the colliding air vortices with each other to separate the unburned carbon portion from the second portion, pulverizing the unburned carbon portion and the second portion by repeated collision, segregating the separated and pulverized unburned carbon portion and the second portion according to centrifugal force resulting from differences in mass, and capturing the now segregated and pulverized unburned carbon portion and second portion to allow for later convenient use.
According to another embodiment of the invention there is provided a separation device, comprising: a casing, the casing includes an inlet for receiving a first material containing at least an unburned carbon portion into the casing, first means for separating the first material into the unburned carbon portion and a second portion, the first means includes second means for reducing in size the unburned carbon portion into a first reduced-size portion and the second portion into a second reduced-size portion, the first means in the casing, segregation means for receiving the first reduced-size portion and the second reduced-size portion from the casing and segregating the first reduced-size portion from the second reduced-size portion for later use whereby the separation device operates economically and effectively, at least one of the first means, the second means and the segregation means being adjustable according to at least one of a size, a density, and an unburned carbon content of the first material whereby the separation device operates economically and accommodates material variation the first material, a first rotation blade in the first means, the first rotation blade having a first rotation axis, a second rotation blade in the first means, the second rotation blade having a second rotation axis, the first rotation blade opposing the second rotation blade in the casing along a common axis of rotation, a pulverization chamber defined between the casing and the first rotation blade and the second rotation blade, the pulverization chamber includes a first width defined as a separation between the first rotation blade and the second rotation blade, the first width being adjustable according to at least the size, the density, and the unburned carbon content of the first material, whereby the separation device is adaptable according to variations in the first material, the first rotation blade includes a blade quantity and a first shape adapted to an inside surface of the casing, the second rotation blade includes a blade quantity and a second shape adapted to the inside surface of the casing, at least one of the first rotation blade and the second rotation blade being rotationally operable at least one of an opposite and a same direction of at least the other of the first rotation blade and the second rotation blade, the first rotation blade and the second rotation blade being rotationally operable according to the inside surface to create circulating vortices within the casing sufficient to cause the separation and the reduction in size of the first material by fracture impact and shear stress, a suction device, a connecting channel connects the suction device to the casing, the suction device drawing gas into the inlet, over the first rotation blade, into the pulverization chamber, and over the second rotation blade to the segregation means to assist the vortices to transport the first material into the separation device for processing, at least one of a first and a second outlet opening on the casing, the at least one outlet opening receiving the first reduced-size portion and the second reduced-size portion from the casing and transferring the first reduced-size portion and the second reduced-size portion to the segregation means, a first storage part in the segregation means, and a second storage part in the segregation means.
According to another embodiment of the invention there is provided a separation device, comprising: a casing, a first rotation blade and a second rotation blade inside the casing operating about a common rotational axis, the first rotation blade and the second rotation blade facing each other in the casing, a pulverization chamber being defined as a space bounded by the first and the second rotation blades and the casing, an inlet opening in the casing adjacent the first rotational blade, the first inlet opening having a shape for receiving a particulate first material containing at least an unburned carbon portion and a second portion, at least one of a first discharge opening and a second discharge opening in the casing adjacent the second rotational blade, the first discharge opening having a position adjacent the common rotational axis of the second rotational blade, and a second discharge opening having a position adjacent an outer circumference of the second rotation blade, and a suction device being connected to the casing opposite the first discharge opening and operating to draw the first particulate material into the casing.
According to another embodiment of the invention there is provided a separation device, wherein: at least of the first rotation blade and the second rotation blade being rotationally operable at least one of an opposite direction and a same direction of at least the other of the first rotation blade and the second rotation blade.
According to another embodiment of the invention there is provided a separation device, further comprising: the first discharge opening, the second discharge opening, and at least one segregation device on at least one of the first discharge opening and the second discharge opening receiving at least one of the unburned carbon portion and the second portion of the first material after precessing.
According to another embodiment of the present invention there is provided a separation device comprising: a casing, the casing includes an inlet for receiving a first material containing at least an unburned carbon portion, first means for separating the first material into the unburned carbon portion and a second portion, the first means includes second means for reducing in size the unburned carbon portion into a first reduced-size portion and the second portion into a second reduced-size portion, the first means in the casing, segregation means for receiving the first reduced-size portion and the second reduced-size portion from the casing and segregating the first reduced-size portion from the second reduced-size portion for later use whereby the separation device operates economically and effectively, at least one of the first means, the second means and the segregation means being adjustable according to at least one of a size, a density, and an unburned carbon content of the first material whereby the separation device operates economically and accommodates material variation the first material, and means for operating the separation device to separate and segregate the unburned carbon particles from the second particles.
According to another embodiment of the present invention, there is provided a separation device, wherein the means for operating includes the steps of: forming a pulverization chamber between the casing and a first and a second rotation blade, the first and the second rotation blades disposed on opposing sides of the pulverization chamber along a common rotational centerline, rotating at least one of the first and the second rotation blades about the common rotational centerline sufficient to create colliding vortices within the pulverization chamber, supplying the first material as particles into the casing at the inlet and the unburned carbon portion having a first specific gravity lower than a second specific gravity of the second portion, separating the first material into the unburned carbon portion and the second portion through at least one of a first process of self-collision with other first material particles and a second process of equipment-collision with the casing and the first and the second rotation blades, reducing in size the unburned carbon portion and the second portion through repeated the at least one process, and segregating the reduced in size unburned carbon portion from the reduced in size second portion, whereby the method for separating operates effectively with increased speed and efficiency.
According to another embodiment of the present invention, there is provided a pulverizer for pulverizing an affluent from a furnace comprising: means for urging said effluent through said pulverizer, at least first and second blades in said pulverizer, and means for rotating said first and second blades at a separation, in a direction, and at a speed effective to form a plurality of vortices which cause multiple collisions of particles of said effluent whereby said particles are separated and reduced in size.
The above, and other objects, features, and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.