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Title: Cleaning and dewatering fine coal

Abstract

Fine coal is cleaned of its mineral matter impurities and dewatered by mixing the aqueous slurry containing both with a hydrophobic liquid, subjecting the mixture to a phase separation. The resulting hydrophobic liquid phase contains coal particles free of surface moisture and droplets of water stabilized by coal particles, while the aqueous phase contains the mineral matter. By separating the entrained water droplets from the coal particles mechanically, a clean coal product of substantially reduced mineral matter and moisture contents is obtained. The spent hydrophobic liquid is separated from the clean coal product and recycled. The process can also be used to separate one type of hydrophilic particles from another by selectively hydrophobizing one.

Inventors:
; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1400259
Patent Number(s):
9,789,492
Application Number:
13/576,067
Assignee:
VIRGINIA TECH INTELLECTUAL PROPERTIES, INC. NREL
DOE Contract Number:
FC26-05NT42457
Resource Type:
Patent
Resource Relation:
Patent File Date: 2011 Jan 31
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Yoon, Roe-Hoan, Eraydin, Mert K., and Freeland, Chad. Cleaning and dewatering fine coal. United States: N. p., 2017. Web.
Yoon, Roe-Hoan, Eraydin, Mert K., & Freeland, Chad. Cleaning and dewatering fine coal. United States.
Yoon, Roe-Hoan, Eraydin, Mert K., and Freeland, Chad. 2017. "Cleaning and dewatering fine coal". United States. doi:. https://www.osti.gov/servlets/purl/1400259.
@article{osti_1400259,
title = {Cleaning and dewatering fine coal},
author = {Yoon, Roe-Hoan and Eraydin, Mert K. and Freeland, Chad},
abstractNote = {Fine coal is cleaned of its mineral matter impurities and dewatered by mixing the aqueous slurry containing both with a hydrophobic liquid, subjecting the mixture to a phase separation. The resulting hydrophobic liquid phase contains coal particles free of surface moisture and droplets of water stabilized by coal particles, while the aqueous phase contains the mineral matter. By separating the entrained water droplets from the coal particles mechanically, a clean coal product of substantially reduced mineral matter and moisture contents is obtained. The spent hydrophobic liquid is separated from the clean coal product and recycled. The process can also be used to separate one type of hydrophilic particles from another by selectively hydrophobizing one.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month =
}

Patent:

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  • A wet mechanical process is described for cleaning, upgrading and dewatering fine coal. The process provides for forming an aqueous feed slurry of fine coal and its associated contaminant particles wherein all particles have a particle portion size of less than about 6 mm ranging to zero. The feed slurry is separated into coal slurry and refuse slurry portions in a spiral gravity concentrator by removing contaminants having a particle size greater than about 0.15 mm. The concentrated coal slurry is then fed to a hydrocyclone separator where all of the ultra-fine silt material having a particle size of lessmore » than 0.15 mm is removed and the coal particle fraction 6 mm to 0.15 mm is accumulated and thoroughly dewatered.« less
  • Aqueous slurries of fine coal are dewatered by a process which comprises mixing a mixture of a water-soluble organopolysiloxane and a water-emulsifiable organopolysiloxane with the slurry, separating the slurry to recover the fine coal and further drying the fine coal, if desired. The use of a mixture of a watersoluble organopolysiloxane and a water-emulsifiable organopolysiloxane unexpectedly provides improved separating and/or improved drying of fine coal compared to a dewatering process that uses only one of the organopolysiloxanes.
  • A method and mechanism for dewatering fine coal or the like by a filtering operation including a horizontally disposed cylindrical housing defining a pressure chamber within, an intermittently movable filter belt wrapping support rolls for the belt at each end with the rolls having driving and braking devices, movable sealing devices positioned at openings to the chamber to seal the belt where it extends into and out of the chamber, a support for the belt with means for draining filtrate dewatered from the coal, and means to apply pressure to the chamber above the belt for dewatering the coal andmore » for providing pressure beneath the support for the belt to balance forces within the housing.« less
  • Aqueous slurries of fine coal are dewatered by a process which comprises mixing an organopolysiloxane with the slurry, separating the slurry to recover the fine coal and further drying the fine coal, if desired. The use of water-soluble organopolysiloxanes or water-emulsifiable organopolysiloxanes provides improved separating and/or improved drying of fine coal in the dewatering process that is disclosed.
  • If successful, the novel Hydrophobic Dewatering (HD) process being developed in this project will be capable of efficiently removing moisture from fine coal without the expense and other related drawbacks associated with mechanical dewatering or thermal drying. In the HD process, a hydrophobic substance is added to a coal-water slurry to displace water from the surface of coal, while the spent hydrophobic substance is recovered for recycling. For this process to have commercialization potential, the amount of butane lost during the process must be small. Earlier testing revealed the ability of the hydrophobic dewatering process to reduce the moisture contentmore » of fine coal to a very low amount as well as the determination of potential butane losses by the adsorption of butane onto the coal surface. Work performed in this quarter showed that the state of oxidation affects the amount of butane adsorbed onto the surface of the coal and also affects the final moisture content. the remaining work will involve a preliminary flowsheet of a continuous bench-scale unit and a review of the economics of the system. 1 tab.« less