Desulfurization of coal by oxidation in alkaline solutions
On the basis of this work and previous studies, it has been demonstrated that high-sulfur bituminous coals can be desulfurized by leaching them with hot, dilute solutions of alkali containing dissolved oxygen under pressure. Dilute alkaline solutions have been shown to be more effective than acidic solutions by removing more sulfur under similar conditions. Among various alkalis tested, sodium carbonate or bicarbonate are among the most effective and lowest in cost. Oxydesulfurization with alkaline solutions appears to remove more inorganic than organic sulfur from coal. It has been shown that most of the sulfur can be extracted fairly rapidly from small particles of nearly pure pyrite or from pulverized coal containing sulfur which is largely in the form of pyrite. On the other hand, the removal of sulfur from physically precleaned coal containing a relatively high proportion of organic sulfur has been only partially successful. The results reported indicate that the removal of organic sulfur may depend on destroying the organic structure of the coal. Leaching experiments with various coals have shown that at moderate temperature, for example, 150/sup 0/C, the total quantity of sulfur extracted in a given period of time increases with increasing oxygen partial pressure. On the other hand, the heating value recovery is not affected significantly by increasing oxygen pressure. For coal with a high proportion of pyritic sulfur, the total sulfur reduction reaches a maximum when leaching is conducted somewhere between 120 and 160/sup 0/C depending on the oxygen partial pressure. However, for coal with a high proportion of organic sulfur, the total sulfur reduction increases continuously with increasing temperature. The heating value recovery is also affected by temperature.
- Research Organization:
- Ames Lab., IA (USA)
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 6350099
- Report Number(s):
- IS-M-318; CONF-801104-15; ON: DE81023741
- Resource Relation:
- Conference: 73. annual meeting of the American Institute of Chemical Engineers, Chicago, IL, USA, 12 Nov 1980
- Country of Publication:
- United States
- Language:
- English
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Advanced development of fine coal desulfurization and recovery technology. Quarterly technical progress report, October 1, 1977--December 30, 1977
Coal desulfurization by leaching with alkaline solutions containing oxygen
Related Subjects
ACID CARBONATES
CHEMICAL REACTIONS
BITUMINOUS COAL
DESULFURIZATION
LEACHING
IRON SULFIDES
OXYGEN
SODIUM CARBONATES
SODIUM COMPOUNDS
CLEANING
HIGH TEMPERATURE
OXIDATION
PRESSURE DEPENDENCE
PYRITE
TEMPERATURE EFFECTS
ALKALI METAL COMPOUNDS
BLACK COAL
CARBON COMPOUNDS
CARBONACEOUS MATERIALS
CARBONATES
CHALCOGENIDES
COAL
DISSOLUTION
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
IRON COMPOUNDS
MATERIALS
MINERALS
NONMETALS
ORES
OXYGEN COMPOUNDS
PYRITES
SEPARATION PROCESSES
SULFIDES
SULFUR COMPOUNDS
SULFUR ORES
TRANSITION ELEMENT COMPOUNDS
010402* - Coal
Lignite
& Peat- Purification & Upgrading