Stripping operation volatile organic compound

Oxidation of cumene to cumene hydroperoxide is usually achieved in three to four oxidizers in series, where the fractional conversion is about the same for each reactor. Fresh cumene and recycled cumene are fed to the first reactor. Air is bubbled in at the bottom of the reactor and leaves at the top of each reactor. The oxidizers are operated at low to moderate pressure. Due to the exothermic nature of the oxidation reaction, heat is generated and must be removed by external cooling. A portion of cumene reacts to form dimethylbenzyl alcohol and acetophenone. Methanol is formed in the acetophenone reaction and is further oxidized to formaldehyde and formic acid. A small amount of water is also formed by the various reactions. The selectivity of the oxidation reaction is a function of oxidation conditions temperature, conversion level, residence time, and oxygen partial pressure. Typical commercial yield of cumene hydroperoxide is about 95 mol % in the oxidizers. The reaction effluent is stripped off unreacted cumene which is then recycled as feedstock. Spent air from the oxidizers is treated to recover 99.99% of the cumene and other volatile organic compounds. 

Potential applications for this technology include the treatment of airstreams contaminated with volatile organic compounds (VOCs) from air stripping, soil vapor extraction, industrial air emissions, and for the cleaning of air in closed environments. PCO is best suited for waste streams with low concentrations of contaminants, and with low to medium flow rates. The AIR-11 process can operate consistently in conditions where flow rates and VOC concentrations are highly variable, even intermittent. 

Air emissions from surface coating operations result from the evaporation of the organic solvents in the coatings and consist primarily of volatile organic compounds (VOCs). Aim of this paper is to present an innovative and sustainable process based on VOC absorption. An absorption tower is fed on the top by oil which efficiently absorbs at low temperature the VOCs contained by the off-gas which enters the tower at its bottom. Saturated oil from the column is then stripped at high temperature in a vacuum system which condenses VOCs at a temperature slightly below the ambient temperature. Stripped oil is then recycled to the absorption tower. 

Concentration Methods. The GCMS analysis of an environmental sample starts with the isolation of the organic compounds from the matrix (air, water, food, etc.) into a form suitable for introduction into the GCMS instrument, typically a solution in a volatile solvent. This concentration step includes essentially three major methods vapor stripping, solvent extraction, and lipophilic adsorption. We have recently reviewed the detailed operation of these methods (Ij, (See also Bellar, Budde and Eichel-berger, this volume) but their general features will be outlined here. 

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