Effect of surfactant washing on enhanced dewatering of fine coal. [Microstructure and porosity of coal filter cakes]
The final moisture content of fine coal filter cakes in coal preparation plants is determined by the filtration and dewatering process. Washing the coal filter cake with a surfactant solution is a potentially economical technique to reduce the final moisture in a fine coal filter cake. The microscopic structure of the porous coal filter cake determines the relative permeability, porosity and final moisture content of the coal filter cake. An experimental study of washing fine coal filter cakes formed from coal-water slurries was conducted. The effect of surfactants on the structure of fine coal filter cakes and the final moisture of these filter cakes was investigated. The filter cake structure was determined using the Cahn and Fullman section chord method. This micrographic technique of quantitative stereology utilized an optical microscope and an image analyzer to measure particle and pore sizes. The washing phenomena using Triton X-114 and Aerosol-OT was investigated to determine the ability of surfactants to enhance the dewatering of fine coal. A significant reduction in final moisture content was achieved by washing the filter cake with a 100 ppM Aerosol-OT solution. While Triton X-114 can also produce a significant reduction in the final moisture content in a filter cake, the amount of surfactant adsorbed from the wash liquor onto the coal in the filter cake was, however, more than Aerosol-OT. Wash ratios of ten gave optimum results for both types of surfactants. The effects of washing on particle and pore size distributions in the coal filter cake were analyzed by micrographic measurement. The mean size of the particles and pores was used to correlate the washing results. Comparisons were made between double distilled water filter cakes and double distilled water filter cakes washed with either double distilled water or surfactant solutions. Experimental results are discussed. 25 refs., 68 figs., 32 tabs.
- Research Organization:
- Oak Ridge Associated Universities, Inc., TN (USA)
- DOE Contract Number:
- AC05-76OR00033
- OSTI ID:
- 5591385
- Report Number(s):
- DOE/OR/00033-T99; ON: DE85015012
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products. Thesis. Submitted to Univ. of Pittsburgh, Pennsylvania
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COAL FINES
FILTRATION
PARTICLE SIZE
WASHING
WATER REMOVAL
SURFACTANTS
CORRELATIONS
EXPERIMENTAL DATA
FUEL SLURRIES
MICROSTRUCTURE
MIXTURES
MOISTURE
PERMEABILITY
POROSITY
WATER
CLEANING
CRYSTAL STRUCTURE
DATA
DISPERSIONS
FUELS
HYDROGEN COMPOUNDS
INFORMATION
NUMERICAL DATA
OXYGEN COMPOUNDS
REMOVAL
SEPARATION PROCESSES
SIZE
SLURRIES
SUSPENSIONS
013000* - Coal
Lignite
& Peat- Transport
Handling
& Storage