Mechanistic modeling of pollutant removal, temperature, and evaporation in chemical air scrubbers

Chemical air scrubbers reduce the concentration of water-soluble components such as ammonia from the outgoing ventilation air through absorption in water, followed by chemical conversions and removal of the end products. A mechanistic model for a countercurrent air scrubber was set up. Mass balances for ammonia, hydrogen sulfide, nitrous oxide, and methane were implemented, as well as the water mass balance and heat balances. The model was validated against experimental data from a conventional fattening pig housing facility. The effect of influent characteristics, design parameters, and control handles on the removal efficiency, the temperature profile, and the water evaporation rate were investigated through simulation. The model was able to describe the behavior of a countercurrent chemical air scrubber

Computational analysis of transitional airflow through packed columns of spheres using the finite volume technique

Copyright © 2010 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Computers and Chemical Engineering. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Computers and Chemical Engineering, Volume 34 Issue 6 (2010), DOI: 10.1016/j.compchemeng.2009.10.013We compare computational simulations of the flow of air through a packed column containing spherical particles with experimental and theoretical results for equivalent beds. The column contained 160 spherical particles at an aspect ratio N=7.14N=7.14, and the experiments and simulations were carried out at particle Reynolds numbers of (RedP=700−5000)(RedP=700−5000). Experimental measurements were taken of the pressure drop across the column and compared with the correlation of Reichelt (1972) using the fitted coefficients of Eisfeld and Schnitzlein (2001). An equivalent computational domain was prepared using Monte Carlo packing, from which computational meshes were generated and analysed in detail. Computational fluid dynamics calculations of the air flow through the simulated bed was then performed using the finite volume technique. Results for pressure drop across the column were found to correlate strongly with the experimental data and the literature correlation. The flow structure through the bed was also analysed in detail

Flow and heat transfer in air-lift systems

SIGLEAvailable from British Library Document Supply Centre- DSC:D65751/86 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Heat exchange engineering Advances in design and operation

SIGLEAvailable from British Library Document Supply Centre- DSC:q93/10698 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Predictive characterization of mean voidage in packed beds

Abstract-A generalized mean voidage correlation has been derived to provide reliable prediction of mean voidage in packed beds of spherical and cylindrical particles. From geometrical considerations, the correlation is extended to cover beds of hollow cylindrical pellets. NOMENCLATURE d j internal diameter do outer diameter dp dp, particle diameter equivalent sphere diameter d, diameter ratio d, tube diameter f empirical factor H height of cylindrical particle n exponent Greek symbols f m mean voidage of packed bed f h mean voidage of bed of hollow cylindrical particles 4> sphericit