Moist caustic leaching of coal
- Elizabeth, PA
A process 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.degree. 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.
- Research Organization:
- Pittsburgh Energy Technology Center
- Assignee:
- United States of America as represented by United States (Washington, DC)
- Patent Number(s):
- US 5312462
- OSTI ID:
- 869300
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
15
300
35
50
90
acid
added
aqueous
aqueous caustic
aqueous slurry
ash
ash content
atmosphere
caustic
caustic leaching
caustic solution
chamber
closed
closed heat
closed reaction
coal
coal feed
coal slurry
content
degree
desulfurized
dried
evaporated
feed
form
heated
heated reaction
inert
inert atmosphere
introduced
kept
koh
leaching
mixture
moist
mole
mole percent
naoh
neutralize
particulate
particulate coal
percent
percent na
process
produce
range
ratio
reaction
reaction chamber
reducing
reintroduced
remaining
remove
removed
slurry
solution
sufficient
sulfur
temperature
thereafter
washed
water
water content
weight
weight ratio