The treatment of some low-rank coals with carbon dioxide water: Effects on slurry-relevant properties: Final report

Technical Report · Mon Sep 01 00:00:00 EDT 1986

OSTI ID:6747625

Slegeir, W; Sanchez, J; Coughlan, R; Sapienza, R; Butcher, T; Healy, F

This project is concerned with the results of employing CO/sub 2//H/sub 2/O treatments on two low-rank coals. The coals employed in this project were North Dakota lignite from the Indianhead Mine and Utah subbituminous from the Sufco mine. This project is concerned with changes in slurry-relevant characteristics for these low-rank coals due to such treatments. These characteristics include equilibrium moisture, ash content and composition, grindability and slurry rheology. Batch CO/sub 2//water treatments on North Dakota Indianhead lignite afforded a reduction in coal-bound moisture, affording as much as a 35% decrease in equilibrium moisture content. The resulting treated lignite also proved to be a ''cleaner'' coal, with a 30 to 35% reduction in ash content. For the Utah Sufco coal, no appreciable changes in equilibrium moisture were attained and the ash contents generally only slightly reduced Sufco. However, for the more severe treatment, alkaline and alkaline earth were lowered appreciably, with a commensurate increase in ash fusion temperature. For both coals, some improvements in grindability were realized under the most severe treatment conditions (80/sup 0/C, 1200 psi). The less severe conditions afforded little changes in grindability. Some measurements taken of the rheology of treated -200 mesh Indianhead coal slurries have shown non-Newtonian behavior. These slurries settled rapidly when concentrations greater than 50% were reached, hence viscosity measurements were difficult to obtain. Although the mechanism of CO/sub 2//H/sub 2/O action on coal is not clear, the results of this project are consistent with an ion-exchange process, whereby the basic components are exchanged with the hydronium ion of the CO/sub 2//H/sub 2/O mixture. Such ion exchange may lead to other changes in the coal matrix. 38 refs., 8 figs, 18 tabs.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6747625
• Report Number(s): BNL-39372; ON: DE87006739
• Resource Relation: Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
CARBON DIOXIDE
SOLVENT PROPERTIES
FUEL SLURRIES
RHEOLOGY
LIGNITE
CHEMICAL COMPOSITION
CLEANING
GRINDING
SUBBITUMINOUS COAL
WATER
ASH CONTENT
COAL PREPARATION
COAL RANK
EXPERIMENTAL DATA
MEDIUM PRESSURE
MEDIUM TEMPERATURE
MOISTURE
BROWN COAL
CARBON COMPOUNDS
CARBON OXIDES
CARBONACEOUS MATERIALS
CHALCOGENIDES
COAL
COMMINUTION
DATA
DISPERSIONS
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
INFORMATION
MACHINING
MATERIALS
MIXTURES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
SLURRIES
SUSPENSIONS
010300* - Coal
Lignite
& Peat- Preparation- (1987-)
010600 - Coal
Lignite
& Peat- Properties & Composition