Kinetics of wet oxidation of biological sludges from coal-conversion wastewater treatment
Combustible organics in aqueous solutions or suspensions, which are characteristic of waste treatment effluent from coal liquefaction, may be treatable by wet oxidation. The wet oxidation of model compounds (phenol in water or phenol in municipal waste sludge) in a batch autoclave reactor was found to proceed rapidly to 99% conversion in less than 15 min for temperatures between 185 and 230/sup 0/C, oxygen pressures between 2000 and 1300 psig, and initial phenol concentrations of 2.5, 10, and 50 g/L. At 10 g/L initial concentration, the reaction rate was independent of the stirring rate, indicating that mass-transfer limitations were unimportant. The reaction occurs in three phases: a slow induction period, a fast first-order reaction with a low activation energy of 4.9 kcal/gmol, followed by a slow first-order reaction. During the reaction a variety of colored intermediates (catechol, succinic acid, hydroquinine) form. It is postulated that the fast portion of the reaction sequence follows free-radical mechanism. Solids settling and turbidity prevented accurate analytical analysis of the phenol in sludge samples, although qualitative results indicate that the disappearance of phenol follows a path similar to that in the phenol-water system.
- Research Organization:
- Oak Ridge National Lab., TN (USA); Massachusetts Inst. of Tech., Oak Ridge, TN (USA). School of Chemical Engineering Practice
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6050883
- Report Number(s):
- ORNL/MIT-332; ON: DE82000525
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COAL LIQUEFACTION PLANTS
WASTE PROCESSING
PHENOL
OXIDATION
SLUDGES
AQUEOUS SOLUTIONS
AUTOCLAVES
COMBUSTION
HIGH PRESSURE
KINETICS
MEDIUM PRESSURE
PRESSURE DEPENDENCE
SOLID WASTES
TEMPERATURE DEPENDENCE
AROMATICS
CHEMICAL REACTIONS
DISPERSIONS
HYDROXY COMPOUNDS
INDUSTRIAL PLANTS
MANAGEMENT
MIXTURES
ORGANIC COMPOUNDS
PHENOLS
PROCESSING
SOLUTIONS
THERMOCHEMICAL PROCESSES
WASTE MANAGEMENT
WASTES
010800* - Coal
Lignite
& Peat- Waste Management
010405 - Coal
Lignite
& Peat- Hydrogenation & Liquefaction