Auto-ignition and upper explosion limit of rich propane-air mixtures at elevated pressures
ABSTRACT The auto-ignition limits of propane-air mixtures at elevated pressures up to 15 bar and for concentrations from 10 mol% up to 70 mol% are investigated. The experiments are performed in a closed spherical vessel with a volume of 8 dm3. The auto-ignition temperatures decrease from 300 degrees C to 250 degrees C when increasing the pressure from 1 bar to 14.5 bar. It is shown that the fuel concentration most sensitive to auto-ignition depends on initial pressure. A second series of experiments investigates the upper flammability limit of propane-air mixtures at initial temperatures up to 250 degrees C and pressures up to 30 bar near the auto-ignition area. Finally the propane auto-oxidation is modelled using several detailed kinetic reaction mechanisms and these numerical calculations are compared with the experimental results.
Conference Paper: Subband coding with modified multipulse LPC for high quality audio[Show abstract] [Hide abstract]
ABSTRACT: A modified multipulse excitation linear predictive coding (MMPLPC) structure combined with a subband (SB) technique is proposed to encode audio signals of 15-kHz bandwidth. The bit allocation is dynamically adapted according to both the signal power in different subbands and a perceptual hearing model. Informal listening tests showed that high fidelity audio coding can be achieved at bit rates of less than 86 kbit/s by SB-MMPLPC.< >Acoustics, Speech, and Signal Processing, 1993. ICASSP-93., 1993 IEEE International Conference on; 05/1993
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ABSTRACT: Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 °C. First, its auto-ignition temperature is measured 365 °C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 °C to 255 °C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.Journal of hazardous materials 09/2010; 185(1):416-22. DOI:10.1016/j.jhazmat.2010.09.049 · 4.33 Impact Factor
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ABSTRACT: An experimental demonstration of the oxidative dehydrogenation of propane (ODHP) in a lab-scale packed bed membrane reactor has been performed. Experiments were carried out with both premixed and distributed oxygen feed over a Ga2O3/MoO3 catalyst and compared, and the influence of the gas composition, flow rate and the extent of dilution was investigated. The experimental results were found to compare very well with detailed reactor simulations. The results revealed that, in comparison with conventional reactor concepts for the ODHP (fixed bed with premixed reactants feed), a significantly higher propylene yield can be achieved at higher propane conversions in a packed bed membrane reactor.Chemical Engineering Science 11/2010; 65(22):6029-6035. DOI:10.1016/j.ces.2010.08.037 · 2.61 Impact Factor