Moist caustic leaching of coal

Patent · Tue May 17 04:00:00 EDT 1994

OSTI ID:7041489

Nowak, M A

A process is described for reducing the sulfur and ash content of coal. Particulate coal is introduced into a closed heated reaction chamber having an inert atmosphere to which is added 50 mole percent NaOH and 50 mole percent KOH moist caustic having a water content in the range of from about 15% by weight to about 35% by weight and in a caustic to coal weight ratio of about 5 to 1. The coal and moist caustic are kept at a temperature of about 300 C. Then, water is added to the coal and caustic mixture to form an aqueous slurry, which is washed with water to remove caustic from the coal and to produce an aqueous caustic solution. Water is evaporated from the aqueous caustic solution until the water is in the range of from about 15% by weight to about 35% by weight and is reintroduced to the closed reaction chamber. Sufficient acid is added to the washed coal slurry to neutralize any remaining caustic present on the coal, which is thereafter dried to produce desulfurized coal having not less than about 90% by weight of the sulfur present in the coal feed removed and having an ash content of less than about 2% by weight. 1 figure.

• Assignee: Dept. of Energy, Washington, DC (United States)
• Patent Number(s): US 5312462; A
• Application Number: PPN: US 7-956933
• OSTI ID: 7041489
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010402* -- Coal
Lignite
& Peat-- Purification & Upgrading
ALKALI METAL COMPOUNDS
ALKALINE HYDROLYSIS
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
COAL
DEASHING
DECOMPOSITION
DESULFURIZATION
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
HYDROLYSIS
HYDROXIDES
LYSIS
MATERIALS
OXYGEN COMPOUNDS
POTASSIUM COMPOUNDS
POTASSIUM HYDROXIDES
SODIUM COMPOUNDS
SODIUM HYDROXIDES
SOLVOLYSIS