Chemical desulfurization of coal with Caro's acid

Conference · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5850479

Lin, K L; Liu, D C; Markuszewski, R; Bautista, R G

The effects of the amount and concentration of Caro's acid (H/sub 2/SO/sub 5/), the temperature, presence of hydrogen perioxide, and coal particle size on the desulfurization of coal have been investigated. Caro's acid was prepared from ammonium peroxydisulfate and sulfuric acid using a commercial procedure and was analyzed by conventional techniques. A typical preparation contained 11 to 14 H/sub 2/SO/sub 5/, 0.1 to 0.7 H/sub 2/O/sub 2/, 0.5 H/sub 2/S/sub 2/O/sub 8/, and 10 to 11.5 H/sub 2/SO/sub 4/ (all in wt %). Its desulfurization potential was tested on an Illinois No. 6 run-of-mine coal with a heating value of 9134 Btu/lb. Using -100 mesh coal, 10 wt % Caro's acid, and a pulp density of 16%, it was possible to remove about 55% of the total sulfur from coal in one hour while stirring at an ambient temperature of 23/sup 0/C. The recovery of coal and the recovery of heating value were about 90%. The percent desulfurization, leaching of iron, and consumption of Caro's acid were studied at different reaction conditions. The reaction was exothermic; raising the temperature above ambient did not improve the desulfurization appreciably, but it did increase the consumption of Caro's acid. The presence of hydrogen peroxide in Caro's acid also did not provide any advantage in the desulfurization scheme. The ratio of Caro's acid to the amount of pyritic sulfur in coal was more important than the absolute amount or concentration of H/sub 2/SO/sub 5/. Using coal particles greater than 70 mesh increased the leaching time required for maximum desulfurization, while using coal finer than 200 mesh resulted in greater consumption of Caro's acid. Under best conditions, about 5.3 moles of Caro's acid were consumed per mole of sulfur removed, corresponding to about 140% of the theoretical value required for the oxidation of pyrite. Nevertheless, its consumption was much lower than that of H/sub 2/O/sub 2/ + H/sub 2/SO/sub 4/ mixtures in related schemes for coal desulfurization. 16 refs., 16 figs., 2 tabs.

• Research Organization: Ames Lab., IA (USA); Iowa State Univ. of Science and Technology, Ames (USA). Dept. of Chemical Engineering
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5850479
• Report Number(s): IS-M-569; CONF-850982-3; ON: DE86011435
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010402* -- Coal
Lignite
& Peat-- Purification & Upgrading
CALORIFIC VALUE
CARBONACEOUS MATERIALS
CHEMICAL COMPOSITION
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COAL
COAL FINES
COMBUSTION PROPERTIES
DATA
DESULFURIZATION
DISSOLUTION
ENERGY SOURCES
EXPERIMENTAL DATA
FOSSIL FUELS
FUELS
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
INFORMATION
INORGANIC ACIDS
LEACHING
MATERIALS
MEDIUM TEMPERATURE
NUMERICAL DATA
OXYGEN COMPOUNDS
PARTICLE SIZE
PEROXIDES
PERSULFURIC ACID
SEPARATION PROCESSES
SIZE
SULFUR COMPOUNDS
SULFURIC ACID
SYNTHESIS
TEMPERATURE EFFECTS
TIME DEPENDENCE