Removal of Halogens, Carbon Dioxide, and Aerosols From Air in a Spray Tower

Abstract

Tests were made of the removal from air of bromine fluoride and iodine vapors, of atmospheric carbon dioxide, and of two aerosols (of 0.5 and 0.10 micron mean diameter) fronn a multiple nozzle caustic spray tower with gas flow rates up to 6000 cu ft/min. The halogen absorption efficiencies ranged from 60 to 100 per cent, with an average KQa of 13 lb-mol/(hr)(cu ft)(atm). The corresponding average gas rate was 1442 lb/(hr)(sq ft) and the average liquid rate was 112 lb/(hr)(cu ft). The average concentration of potassium hydroxide used was 6 weight per cent. Carbon dioxide runs over a range of gas rates, liquid rates, carbon dioxide concentrations, and potassium hydroxide concentrations showed values of KQa as highas 3.74 lb-mol/(hr)(cu ft)(atm), which is comparable to those obtained in packed towers. The KQa was independent of the gas rate, but increased with liquid rate, carbon dioxide concentration, and potassium hydroxide concentration. Aerosol absorption efficiencies were between 35 and 57 per cent in the tests made. Analysis of the spray contacting mechanism was developed for the purpose of aiding in the design of highly efficient spray scrubbers. f**^ Table I ABSORPTION IN SINGLE-NOZZLE SPRAY TOWER (5-INCH DIAMETER) (Data from ANL-5015) Contact Overall JS^a, Run Absorbed Air Rate, Liquid Rate, lb/(hr) Liquid Rate, Time. Inlet Concn.. ppm lb.mol/(hr)(cu ft)(atm) No. Gas lb/(hr)(sq ft) (sq ft of spray cone) lb/(hr)(cu ft) Seconds Fluoride Other Halide Fluoride Other Halide 1030 3.8 8642 12.4 •Assuming I ppm rather than 0 as the exit concentration * * For fluoride absorption.

A Conceptual Design Study of a Fluoride-Volatility Plant for Reprocessing LMFBR Fuels.

“…153 Released uranium and plutonium hexafluoride vapors constitute special cases, but work in this area by Kessie When gas from a short-cooled fuel is released to the plant ventilation system (for either nuclear power reactors or fuel-reprocessing plants), iodine removal is a serious problem. There are many possible methods for the removal of iodine and its compounds from gas streams.154 Iodine combines with small amounts of organic material in normal air or in the plant environment and is converted to CH3I, which penetrates filters and absorbers that remove elemental iodine.…”