Thermal reactions of aromatics with CaO. Technical progress report, September 1, 1980-April 30, 1981. [Compounds tested -1-methylnaphthalene, toulene, benzene, n-heptane]
Experiments were performed near atmospheric pressure for the temperature range 550 to 950/sup 0/C. Helium carrier gas containing 3 mole % of the vapor phase reactant was passed through approximately 5.5-cm-deep, 0.7-cm-ID packed beds containing calcium oxide or quartz (for comparison studies). Contact times were approximately 2 s and around 5 mg of pure compound were fed in each run. Reaction products and unreacted feed were collected and analyzed. Carbon balances were performed on selected runs. The effects of CaO source and the method of CaO preparation were also investigated. Extents of conversion, and product distributions for n-heptane cracking were similar for calcium oxide and for quartz. However, the temperature for removal of aromatic hydrocarbons from the helium hydrocarbon mixtures in the presence of calcium oxide was reduced 140 to 180/sup 0/C from that with quartz. The temperature required for 20% conversion of each compound in the presence of calcium oxide and quartz respectively were: 1 - methylnaphthalene - 570 and 750/sup 0/C; toluene - 685 and 825/sup 0/C; benzene 750 and 890/sup 0/C; and n-heptane 585 and 610/sup 0/C. The reactivity of the aromatics increased with addition of a methyl group or a second aromatic ring to the molecule. Coke is the major product from the reaction of each aromatic. Methane yields from 1-methylnaphthalene and toluene were lower in the reactions over calcium oxide. On a unit weight basis calcium oxide obtained by calcining calcium hydroxide at final reaction temperatures was more active for benzene cracking than CaO obtained by calcining limestone. Calcium oxide cracking activity declines as coke is deposited on its surface but may be at least partially regenerated by burning off the coke. Apparent activation energies obtained by fitting a single reaction first order decomposition model to the data were lower for aromatics cracking over CaO compared to quartz but the opposite effect was found for n-heptane.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge (USA). Energy Lab.
- DOE Contract Number:
- FG22-80PC30229
- OSTI ID:
- 6438665
- Report Number(s):
- DOE/PC/30229-T1; ON: DE81028760
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
014000* -- Coal
Lignite
& Peat-- Combustion
ACTIVATION ENERGY
ALKALINE EARTH METAL COMPOUNDS
ALKANES
ALKENES
AROMATICS
BENZENE
CALCIUM COMPOUNDS
CALCIUM HYDROXIDES
CALCIUM OXIDES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CARBONATE ROCKS
CHALCOGENIDES
CHEMICAL PREPARATION
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
COKE
COMBUSTION
COMPARATIVE EVALUATIONS
CONDENSED AROMATICS
DATA
ENERGY
ETHYLENE
EXPERIMENTAL DATA
FLUIDIZED-BED COMBUSTION
HEPTANE
HIGH TEMPERATURE
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROXIDES
INFORMATION
LIMESTONE
MEDIUM PRESSURE
METHANE
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
QUARTZ
RESEARCH PROGRAMS
ROCKS
SEDIMENTARY ROCKS
SILICON COMPOUNDS
SILICON OXIDES
SYNTHESIS
THERMOCHEMICAL PROCESSES
TOLUENE
YIELDS