Separation of pyrite from coal in a fluidized bed
AssigneeElectric Power Research Institute, Inc.
InventorsEdward K. Levy, D'Agostini Mark, Damir Latkovic, James W. Parkinson
Life of this patent
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Abstract
Processes and arrangements that provide for the separation of pyrite from coal in a fluidized bed. The processes provide for more efficient and complete stratification of the bed materials in a vertical direction, so that the very top layer of the fluidized ved is coal having a reduced pyrite content. The process includes feeding the coal to be cleaned on top of a layer of magnetite. The process also includes fluidizing the bed until bed-bubbling separation occurs in the absence of steady-state conditions. The cleaned top layer of coal having a reduced pyrite content is then separated from the refuse coal in the bottom of the bed.
Claims27
In a process for the separation of pyrite from coal in a fluidized bed for providing coal having a reduced pyrite content, the process being of the type having the steps of feeding magnetite and coal including pyrite into a bed vessel, whereby a bed of a layer of magnetite and coal including pyrite is formed, fluidizing the bed of magnetite and coal including pyrite, whereby the pyrite is substantially separated from the coal and a coal having a reduced pyrite content is formed, and further whereby a fluidized bed of fluidized material is formed, wherein the solids are stratified in the vertical direction so that a top layer of coal substantially free of pyrite is formed at the very top thereof and with the pyrite being distributed vertically throughout the fluidized bed from the top to the bottom thereof, whereby the fluidized bed has a top layer of fluidized material comprises substantially of coal having a reduced pyrite content is provided and a bottom layer of fluidized material comprises substantially of coal having a higher pyrite content is provided and removing the fluidized material from the fluidized bed, whereby coal having a reduced pyrite content is provided, the improvement thereupon comprised of:
- feeding the magnetite free of coal including pyrite into the bed vessel before the coal including pyrite, whereby a bed of a layer of magnetite free of coal including pyrite is formed;
- feeding the coal including pyrite and free of magnetite into the bed vessel and on top of the bed of the layer of coal including pyrite and free of magnetite disposed on top of a layer of magnetite free of coal including pyrite is formed;
- the bed of magnetite and coal including pyrite, being fluidized until bed-bubbling separation occurs, such that a fluidized bed is formed wherein the solids are stratified in the vertical direction so that a top layer of coal substantially free of pyrite is formed at the very top thereof and with the pyrite being distributed vertically throughout the fluidized bed from the top to the bottom thereof, whereby the fluidized bed has a top layer of fluidized material comprised substantially of coal having a reduced pyrite content is provided;
- and
- separating the product coal in the top layer of fluidized material from the refuse coal in the bottom layer of fluidized material, whereby a product including coal having a reduced pyrite content is provided.
In an arrangement for the separation of pyrite from coal including pyrite, in a fluidized bed, for providing coal having a reduced pyrite content, the arrangement being of the type having:
- a fluidizing bed vessel for receiving therein a material to be fluidized and a fluidizing material;
- a magnetite feeder for feeding magnetite into the bed vessel, whereby a bed of a layer of magnetite is formed;
- a coal feeder for feeding coal including pyrite into the bed vessel and onto the layer of magnetite, whereby a bed of the material to be fluidized including a layer of coal including pyrite disposed on a layer of magnetite is formed;
- means for introducing the fluidizing material into the bed vessel having the bed of the material to be fluidized including the layer of magnetite and the layer of coal including pyrite;
- whereby the bed of material to be fluidized including the layer of magnetite and the layer of coal including pyrite is fluidized in the bed vessel, such that the pyrite is substantially separated from the coal, and further such that a fluidized bed is formed, wherein the solids in the fluidized bed are stratified in the vertical direction so that a top layer of coal substantially free of pyrite is formed at the very top thereof and with the pyrite being distributed vertically throughout the fluidized bed from the top to the bottom thereof, such that the fluidized bed has a top layer of fluidized material substantially comprised of coal having a reduced pyrite content and a bottom layer of fluidized material substantially comprised of coal having a higher pyrite content is provided;
- and
- means for separating the product coal in the top layer of fluidized material from the refuse coal in the bottom layer of fluidized material, whereby coal having a reduced pyrite content is obtained;
- the improvement thereupon comprising:
- the fluidizing bed vessel being a bed-bubbling separation fluidizing bed vessel;
- the magnetite feeder having means that feeds magnetite free of coal including pyrite into the bed vessel, whereby a bed of a layer of magnetite free of coal including pyrite is formed;
- the coal feeder having means that feeds coal including pyrite and free of magnetite into the bed vessel and onto the layer of magnetite free of coal including pyrite;
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- the means for introducing the fluidized material into the bed vessel provides bed-bubbling separation.
Dependencies are inferred from the claim text.