Coal desulfurization by leaching with alkaline solutions containing oxygen

Conference · Sun Jan 01 04:00:00 EST 1978

OSTI ID:6542672

Markuszewski, R; Chuang, K C; Wheelock, T D

It has been demonstrated with a small autoclave reactor that leaching of high-sulfur bituminous coals with hot, dilute solutions of sodium carbonate containing dissolved oxygen under pressure can remove most of the inorganic sulfur and a portion of the organic sulfur. Dilute alkaline leach solutions have been shown to be more effective than neutral or acidic solutions. More concentrated alkaline solutions are less beneficial and even detrimental, causing lower reduction in sulfur and decreasing the heating value recovery. The desulfurization reaction becomes independent of the stirring rate at high stirring speeds. Leaching longer than 1 to 1.5 hr results only in a modest increase in sulfur removal, but the advantage is offset by a decrease in heating value recovery. Increasing the oxygen partial pressure improves the extraction of sulfur without a noticeable decrease in the heating value recovery. The improvement is due mainly to an increase in the removal of organic sulfur, amounting to 30% in some cases. An optimum temperature range has been observed at about 120 to 150/sup 0/C for which the reduction of sulfur is maximum. At higher temperatures, both the extraction of sulfur and the heating value recovery decline significantly. The overall Ames oxydesulfurization process has been shown to be effective in removing almost all of the inorganic sulfur and a significant portion of the organic sulfur under relatively mild conditions. The moderate temperatures and pressures do not require extraordinary equipment, and the alkaline conditions provide a non-corrosive environment. With proper regeneration of the leaching solution, the process should prove an economical method for the chemical cleaning of high-sulfur coal.

• Research Organization: Iowa State Univ. of Science and Technology, Ames (USA). Energy and Mineral Resources Research Inst.
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6542672
• Report Number(s): IS-M-158; CONF-7809119-1
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010402* -- Coal
Lignite
& Peat-- Purification & Upgrading
ALKALI METAL COMPOUNDS
AUTOCLAVES
BITUMINOUS COAL
BLACK COAL
CARBON COMPOUNDS
CARBONACEOUS MATERIALS
CARBONATES
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
COAL FINES
CRYOGENIC FLUIDS
DESULFURIZATION
DISSOLUTION
ELEMENTS
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUELS
IRON COMPOUNDS
IRON SULFIDES
LEACHING
MINERALS
NONMETALS
OPTIMIZATION
ORES
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN
OXYGEN COMPOUNDS
PYRITE
PYRITES
REMOVAL
SEPARATION PROCESSES
SODIUM CARBONATES
SODIUM COMPOUNDS
SULFIDES
SULFUR
SULFUR COMPOUNDS
SULFUR ORES
TRANSITION ELEMENT COMPOUNDS