Method and apparatus for dewatering
OwnerEdward H. Greenwald, Sr.inventor
Life of this patent
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Abstract
An ultra-fine coal particle fraction forms a coal product with particles that are dilatant due to the mechanical stripping of the clay contaminates from the coal surface and the subdividing of the clay to clay platelets which are peptized to maintain discreetness in an aqueous slurry. The coal particles are unflocculated and can produce an aqueously permeable barrier on a sieve. The ultrafine coal product has an increase of 100-150 BTU per pound and when combusted reduced Nox production of 20-40% is realized. In a 15.times.0 micron coal fraction, the sulphur content is significantly reduced.
Claims18
The coal product produced according to a method of treating clay contaminated ultra fine coal particles, said method including the steps of;
- forming an aqueous slurry of clay contaminated ultra fine coal particles;
- mechanically stripping clay contaminants from the surfaces of the coal particles while subdividing the size of the clay contaminant to clay platelets;
- peptizing the clay platelets to impart a state of discreetness in the aqueous slurry;
- collecting a mass of dilatant coal particles in a superimposed relation upon a dilatant coal layer, said dilatant coal layer being defined by forming an aqueously permeable barrier comprised of a dilatant coal layer of collected coal particles from said slurry upon a barrier;
- using the dilatancy of said dilatant coal mass in combination with an applied force for dewatering the coal mass by draining aqueous medium along with peptized clay platelets from the coal mass;
- and
- recovering the coal mass.
The dewatered coal product according to the method consisting of the steps of:
- forming an aqueous slurry of clay contaminated ultra fine coal particles;
- imparting high shear forces to the slurry containing the clay contaminants from the surfaces of the coal particles and to subdivide the size of the clay contaminant to clay platelets without flocculating the ultra-fine coal particles;
- adding a sufficient amount of a peptizing agent to said slurry thereby peptizing the clay platelets to impart a state of discreetness in the aqueous slurry;
- subjecting said peptized aqueous slurry to a size separator selected from the group consisting of a sieve having a barrier layer of aqueous permeable unflocculated dilatent coal thereon, and a filter having a barrier layer of aqueous permeable unflocculated dilatent coal thereon, thereby forming a mass of dilatent coal particles;
- using the dilatency of said dilatent coal mass in combination with an applied force for dewatering the coal mass by draining aqueous medium along with discrete peptized clay platelets from the coal mass;
- and
- recovering the coal mass.
A fine coal product essentially including an ultra fine coal particle fraction, the coal particles being dilatant by the mechanically stripping of clay contaminants from the surface of the coal particles and subdividing the clay to clay platelets in the presence of a peptizing agent to peptize and maintain clay platelets discreet in an aqueous slurry, the dilatant coal particles being unflocculated and capable of producing an aqueously permeable barrier on a sieve for forming a filter cake having a moisture content lower moisture than an ultra fine coal particle fraction before stripped of clay, the reduction of clay contaminants on the coal particles increasing a calorific value at least 100 Btu per pound as determined by a bomb calorimeter.
Dependencies are inferred from the claim text.