No abstract

A method is presented whereby spectral radiation measurements made in a combustion flue gas can be used with a spectral gas absorption model to calculate gas temperature, H2O concentration, CO2 concentration, and total radiation intensity for the gas. Measured spectral intensities from a natural gas-air flame in a 150 kWth furnace were used in conjunction with a spectral gas absorption model to calculate gas temperature and H2O concentration. The measured spectral intensities matched spectral intensities predicted by a one-dimensional intensity model when peaks were shifted and convolved to account for FTIR biases. On the basis of a successful prediction of intensities in the measured range of 1.709–2.128 μm, the calibrated intensity model was used to predict intensities for various wavelength bands including H2O and CO2 relative contributions. The total intensity for a wavelength range of 1–50 μm for the conditions studied was 10 659 W/m2/sr, with an equivalent total gas emissivity of 0.163.

No abstract

Precalciner performance is crucial to the production rate and lifespan of cement kiln systems. The gas-solid flow and pulverized coal combustion processes in an industrial precalciner were numerically modeled to understand the flow patterns and thermal processes in the system. The gas and meal flow rates and properties were measured on-site to determine the boundary conditions for the simulations and to validate the models. The upward swirl of the gas flow in the furnace helped disperse the particles and extend their duration in the precalciner. The O2 and CO2 concentration distributions indicated that the coal particles were well dispersed and fully combusted. The calculations showed that the precalciner outlet temperature was too high which reduces the thermal efficiency and may damage the preheater installed just after the precalciner. Finally, an optimized precalciner was proposed to improve the temperature distribution. The present work can be used for improving the design of industrial precalciners.

No abstract