Removal of volatile compounds

Wang, L.K., Hrycyk, O., and Kurylko, L., Removal of Volatile Compounds and Surfactants from Liquid, US Patent No. 5122165, Office of Patents and Trademarks, Washington, DC, June 1992. 

As shown in Table 1, the two methods for removal of volatile compounds from coffee gave different results. The rotary evaporation technique yielded a distillate with an aroma that... 

Carbon residue A test used to measure the tendency of a base oil to form carbonaceous deposits at elevated temperatures. The Conradson carbon residue test, ASTM D189, determines the residue which remains after pyrolytic removal of volatile compounds in the absence of air. 

Also in this configuration, the membrane acts purely as a support for a vapour-liquid interface and does not contribute to the separation mechanism. Furthermore, the flux is independent of the temperature of the sweep gas. It should be noted that the effect of the feed temperature, solute concentration and velocity on the flux are similar to their effect in DCMD (Lawson and Lloyd, 1997). As in AGMD, this configuration is particularly useful for the removal of volatile compounds (other than water) or dissolved gases from liquid streams. 

Konieczny K, Bodzek M and Panek D (2008), Removal of volatile compounds from the wastewaters by use of pervaporation . Desalination, 223,344-348. 

The industrial process [23, 212, 213] of ethoxylation and propoxylation is usually a semi-batch process. The starter alcohol and KOH are mixed and water is removed by distillation. In a second step, monomers are fed into the reactor, where the feed rate is chosen so as to be able to remove the heat of polymerization and to keep the latent heat of polymerization of unreacted monomers in a safe state. By this process, homopolymers and random copolymers are accessible. Block copolymers are produced by successive feeds of the respective monomers. Catalyst is removed by addition of acids and subsequent crystallization and filtration of precipitated salts. An optional fourth step is the removal of volatile compounds by distillation. 

Cummins, M. D. and Westrick, J. J., Packed Column Air Stripping for Removal of Volatile Compounds, National Conference on Environmental Engineering, A.S.C.E., Minneapolis, 1982. 

Several techniques for the removal of volatile compounds associated with flavor from foods have been reported dynamic headspace (DHS) and purge and trap (PT) [7 9], solvent extraction [10], high vacuum distillation and steam distillation [11], simultaneous steam distillation extraction (SDE) [8,11,12], supercritical fluid extraction (SFE) [13-15], and solid-phase microextraction (SPME) [16,17],... 

The removal of volatile organic compounds (VOC) from air is most often accompHshed by TSA. Air streams needing treatment can be found in most chemical and manufacturing plants, especially those using solvents. At concentrations from 500 to 15,000 ppm, recovery of the VOC from steam used to regenerate activated carbon adsorbent thermally is economically justified. Concentrations above 15,000 ppm ate typically in the explosive range and... 

The commercialization by Kureha Chemical Co. of Japan of a new, highly attrition-resistant, activated-carbon adsorbent as Beaded Activated Carbon (BAC) allowed development of a process employing fluidized-bed adsorption and moving-bed desorption for removal of volatile organic carbon compounds from air. The process has been marketed as GASTAK in Japan and as PURASIV HR (91) in the United States, and is now marketed as SOLD ACS by Daikin Industries, Ltd. 

Removal of Refractory Organics. Ozone reacts slowly or insignificantly with certain micropoUutants in some source waters such as carbon tetrachloride, trichlorethylene (TCE), and perchlorethylene (PCE), as well as in chlorinated waters, ie, ttihalomethanes, THMs (eg, chloroform and bromoform), and haloacetic acids (HAAs) (eg, trichloroacetic acid). Some removal of these compounds occurs in the ozone contactor as a result of volatilization (115). Air-stripping in a packed column is effective for removing some THMs, but not CHBr. THMs can be adsorbed on granular activated carbon (GAG) but the adsorption efficiency is low. 

Volatile organic contaminants occur primarily in groundwaters as a result of the disposal of industrial solvents on the ground or in soakage pits. The removal of these compounds has best been accompHshed by the use of air stripping or adsorption on activated carbon. 

Applications Simultaneous steam distillation-solvent extraction has been in use for many years [163]. Steam distillation combined with continuous liquid extraction is an efficient technique for the removal and isolation of volatile compounds in various matrices (environmental,... 

Steam extraction has been used for gasoline and diesel fuel. High-molecular-weight components of the diesel fuel cannot be removed easily, although a total removal of up to 91% is possible. When used to remove low-volatility compounds in a soil with a high percentage of clay, performance is expected to be ca. 85%. The mobile in situ steam extraction system can reduce VOCs in soils by more than 50% of their initial level. Based on pilot studies, the stationary steam extraction system is expected to have a 90% removal efficiency.54... 

Normally, treatment of coproduced groundwater during hydrocarbon recovery operations will include, as a minimum, oil-water separation and the removal of dissolved volatile hydrocarbon fractions (i.e., benzene, toluene, and total xylenes). In addition, removal of inorganic compounds and heavy metals (i.e., iron) is often required. Dissolved iron, a common dissolved constituent in groundwater, for example, may require treatment prior to downstream treatment processes to prevent fouling problems in air-stripping systems. Heavy metals removal is normally accomplished by chemical precipitation. 

Bisschops, M. A. T., van der Wielen, L. A. M. and Luyben, K. Ch. A. M. in Semel, J. (ed) Process Intensification in Practice, Applications and Opportunities (BHR Group, London, 1999) 229. Centrifugal adsorption technology for the removal of volatile organic compounds from water. 

For most analyses, it is necessary to separate the analytes of interest from the matrix (i.e., soil, sediment, and water). Extraction of analytes can be performed using one or more of the following methods (1) extracting the analytes into a solvent (2) heating the sample, as may be necessary to remove the solvent and for the analysis of volatile compounds and (3) purging the sample with an inert gas, as is also used in the analyses of volatile compounds. 

Organophilic membranes with a preferential permeation of nonpolar compounds are used for the removal of volatile organic components from aqueous and gas streams. 

Wang et al. [42,67,68] have developed innovative biological process and sequencing batch reactors (SBR) specifically for removal of volatile organic compounds (VOCs) and surfactants. Related analytical procedures [57-64,71-91] available for process monitoring and control are available in the literature. 

Bio-Electrics, Incorporated, has developed the Electrofrac Detoxification System to treat hazardous contaminants in soil. The system, which was developed from gasification research, uses electrodes placed in soil to heat the site. There are potential applications of this technology for removal of volatile organic compounds (VOCs), pyrolysis of non-VOCs, treatment of organic residues, and in situ vitrification of soils and asbestos. There have been bench-scale tests of the technology for remediation applications. 

Croy Dewatering Environmental Services, Inc. (Croy), has developed the dual-phase recovery unit for the extraction of groundwater and the removal of volatile organic compounds (VOCs)... 

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