Integrated vapor extraction

Integrated Vapor Extraction and Steam Vacuum Stripping... 

Integrated vapor extraction and steam vacuum stripping can simultaneously treat groundwater and soil contaminated with VOCs. The system developed by AWD Technologies consists of two basic processes a vacuum stripping tower that uses low-pressure steam to treat contaminated ground-water and a soil gas vapor extraction/reinjection process to treat contaminated soil. The two processes form a closed-loop system that provides simultaneous in situ remediation of contaminated groundwater and soil with no air emission. 

Some integrated techniques may be more economical if they can be used simultaneously for soil and groundwater treatment, such as integrated vapor extraction and steam vacuum stripping. 

AquaDetox, integrated vapor extraction and stream vacuum stripping (Cheremisinoff, 1989) VOCs, PCE, and TCE Dow Chemical Co., Ltd. 

Integrated vapor extraction and steam vacuum stripping... 

The process can be integrated with existing technologies, such as thermal desorption, air stripping, or soil vapor extraction. 

A conventional pump-and-treat extraction system is typically designed to recover only ground-water. Integrated or separate systems have also been used to capture free product or contaminated vapor concurrently with groundwater. More detailed information relevant to the application of pump-and-treat at sites contaminated with MTBE and other oxygenates and in general is available in the literature.88-90... 

SORPTION EXPERIMENTS. The extracts were exposed to benzene vapor at several relative vapor pressures (p/p )- Two types of sorption experiments were conducted. Experiments in which the benzene vapor pressure is raised from zero to a higher value are termed integral sorptions. Sorption experiments starting with the extract and vapor in equilibrium at a finite, nonzero pressure, and proceeding to a higher pressure, are termed incremental sorptions. 

Kado, N. Y., J. M. Wing, P. A. Kuzmicky, J. E. Woodrow, H. Ning, J. N. Seiber, and D. P. H. Hsieh, Quantitative Integration of the Salmonella Microsuspension Assay with Supercritical Fluid Extraction of Model Airborne Vapor-Phase Mutagens, Mutat. Res., 271, 253-260 (1992). 

POis separated from methanol by extractive distillation, using water (or in another embodiment, propene glycol) as the extractor. PO is distilled overhead from the extractive column as top stream, while the bottom stream contains methanol and water [17d, fj. The energy integration of the column is one important issue of the patents the vapors of the top stream are compressed, and the condensation heat is returned to the vaporizer employed in the extractive distillation column. 

The major alkaloids in the vapor phase of environmental tobacco smoke are discussed and detailed procedures for their determination are outlined. Time-integrated sampling involves concentrating the alkaloids from the air matrix by trapping on either XAD-4 sorbent resin or on bisulfate-treated glass fiber filters with extraction and analysis by gas chromatography and N-selective detection. These methods are widely used in studying the impact of ETS on indoor air quality in real-life situations. 

Adsorption processes have a number of competitors, including primarily distillation, extractive and azeotropic distillation, absorption, solvent extraction, and, more recently, membrane-based processes. Vapor-liquid-based processes and, in particular, distillation are especially formidable competitors because of their relatively simple flowsheets. Thus, if a separation can be performed easily by distillation, it will usually be the process of choice, based on relatively low capital costs and tolerable, if not low, energy costs. In addition, systems of distillation columns can oftentimes be energy integrated to effect lower energy costs per unit of feed processed than for stand-alone columns. 

Unsteady-state Conditions. Arnold (2) has integrated the Maxwell-Stefan equation for gaseous diffusion in the case of the semi-infinite column, or diffusion from a plane at which the concentrations are kept constant into a space filled with gas extending to infinity, both for vaporization of a liquid into a gas and absorption of a gas by a liquid. It is possible that the resulting equations could be applied successfully to liquid diffusion for similar circumstances, provided that an assumption analogous to Dalton s law for gases can be made and that D is assumed to remain constant. The direct application to extraction operations of such equa-... 

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