Preparation and combustion of low-rank coal/water fuels

Conference · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5651208

Potas, T A; Paulson, L E; Maas, D J; Baker, G G

In the bench-scale studies, eighteen domestic coals, mostly lignite and subbituminous coals, were hydrothermally treated in a one gallon cold-charge autoclave. The treated coals had substantially higher heating values and lower equilibrium moisture contents than their raw coal counterparts. This was due, in part, to the decarboxylation of the raw coal during treatment which increased the relative carbon content and decreased the oxygen content of the coal product. As the carbon dioxide is liberated, chemically bound water and associated inorganic cations (i.e. sodium) are also released from the coal. Also in processing, tars that are formed exude from the interior to the coal particle surface to close pore entrances. This makes the coal product more hydrophobic and decreases the coal's ability to bind water. Hydrothermal treatment causes an increase in the solids content for a pourable slurry (dry solids basis) from 40-45% for the raw coal to a range of 55 to 65 wt% for the HT product. The heating values for the majority of the HT CWF were over 7000 Btu/lb which is comparable to the ''as mined'' heating values of the raw coals. The effect of hydrothermal treatment increased as the coal rank decreased, with the most pronounced change in the coal product obtained with high-moisture lignites. Substantial quantities of slurries were produced for combustion tests in the PDU HT processing. These combustion tests were performed in a 550,000 Btu/hr ash fouling furnace which was modified to utilize a slurry feed. All four CWFs prepared for the combustion tests were burned successfully in this unit. Atomization proved to be no problem with these slurries and all exhibited carbon burnouts approaching or greater than 99%. 7 refs.

• Research Organization: North Dakota Univ., Grand Forks (USA). Energy and Mineral Research Center
• DOE Contract Number: FC21-83FE60181
• OSTI ID: 5651208
• Report Number(s): DOE/FE/60181-217; CONF-860747-1; ON: DE86012367
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
013000* -- Coal
Lignite
& Peat-- Transport
Handling
& Storage
014000 -- Coal
Lignite
& Peat-- Combustion
ATOMIZATION
BROWN COAL
CARBONACEOUS MATERIALS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COAL
COAL PREPARATION
COMBUSTION
DECARBOXYLATION
DISPERSIONS
DRYING
ENERGY SOURCES
FOSSIL FUELS
FUEL SLURRIES
FUELS
HYDROGEN COMPOUNDS
LIGNITE
MATERIALS
MIXTURES
OXIDATION
OXYGEN COMPOUNDS
SLURRIES
SUBBITUMINOUS COAL
SUSPENSIONS
SYNTHESIS
THERMOCHEMICAL PROCESSES
WATER