A continuous process for indirect steam dewatering of lignite
A continuous process is presented for indirect steam drying low rank coal such as sub-bituminous coal, brown coal or lignite. The process accomplishes non-evaporative drying by thermally heating the low rank coal with hot water. The heating raises the low rank coal temperature to a value sufficient to cause water to freely expell from the internal structure of the coal particles; a phenomena discovered in the 1920's. The process utilizes two stages of hot water heating. The first stage recovers heat from the second stage. Final dehydration temperature is achieved in the second stage. A low temperature upward counter-current flow of fresh water displaces hot mineral ladened water through the second stage vessel peripheral screens. The displaced hot water is directed into the lower end of the first stage vessel to flow upward counter-currently to preheat fresh coal. Mineral ladened water is extracted from the first stage through peripheral screens and directed to flash tanks to produce lower temperature steam for heating coal at the front end of the process. Flash tank underflow water is directed to fine coal recovery equipment and then to disposal. The hot water drying process presented in this document utilizes process principals now in common practice in the pulp and paper industry. The machinery is designed by Kamyr, Inc.
- Research Organization:
- Kamyr Inc.
- OSTI ID:
- 5767727
- Report Number(s):
- CONF-831112-
- Journal Information:
- Coal Technol. (Houston); (United States), Vol. 6; Conference: Coal technology '83 - international coal utilization convention, Houston, TX, USA, 15 Nov 1983
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LIGNITE
DRYING
SPRAY DRYING
SUBBITUMINOUS COAL
COAL PREPARATION
HEATING
HOT WATER
MOISTURE
STEAM
BROWN COAL
CARBONACEOUS MATERIALS
COAL
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
MATERIALS
OXYGEN COMPOUNDS
WATER
013000* - Coal
Lignite
& Peat- Transport
Handling
& Storage