Air Stripping of Volatile Organics

1985 ◽  
Vol 28 (3) ◽  
pp. 28-31
Author(s):  
Robert Stallings ◽  
Tony Rogers ◽  
Michael Mullins
Keyword(s):  
Organic Compounds ◽  
Air Force ◽  
Operating Conditions ◽  
Transfer Coefficients ◽  
Air Stripping ◽  
Packed Tower ◽  
Research Triangle ◽  
Active Research ◽  
Gas Liquid Flow ◽  
Active Research Program

The Air Force's Installation Restoration Program includes an active research program into treatments for contaminated groundwater. Packed-tower air stripping of volatile organic compounds (VOCs) from groundwater has proven to be a costeffective and efficient method of treatment. The Research Triangle Institute (RTI) has recently participated in a packed-tower air-stripping test program for the Air Force in which 16 organic compounds in a groundwater plume were identified, and the air-stripping behavior of each was examined. The performance of four different commercial packing materials was evaluated for each of the 16 contaminants over a range of gas-liquid flow ratios. The mass transfer coefficients for each of the contaminants were subsequently calculated, and the most effective operating conditions were determined.

scholarly journals The flow and mass transfer characteristics of concentric gas-liquid flow in an advanced static mixer

2020 ◽  
pp. 24-24
Author(s):  
Huibo Meng ◽  
Zhonggen Li ◽  
Yanfang Yu ◽  
Mengqi Han ◽  
Shuning Song ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Liquid Flow ◽  
Operating Conditions ◽  
Static Mixer ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Local Mass ◽  
Transfer Characteristics ◽  
Local Mass Transfer ◽  
Gas Liquid Flow

The fluid dynamic and mass transfer characteristics of concentric upward gas-liquid flow were studied in the industrial static mixer with four equally spaced helical inserts (FKSM). The numerical simulations of gas volume fraction in Kenics mixer had a good agreement with the numerical and experimental results provided by Rabha et al. The characteristics of radial gas void fraction and local mass transfer coefficients in the FKSM were evaluated under different operating conditions. The velocity profiles of concentric air phase accelerated by the bubble forces firstly became sharp and narrow until z/l=-3.27 and then slowly decreased and stabilized at z/l=-1.5 before entering the first mixing element. Some extra unimodal profile of radial gas holdup gradually generated near the rectangle cross sections of mixing elements. The ?G gradually enlarged from r/R=0.2 to r/R=0.55 and then weakened from r/R=0.65 to r/R=0.874. The air void fractions in the bulk flow region decreased with the increasing initial uniform bubble diameter. The inlet effect of first leading edge enhanced the air phase dispersion and local mass transfer coefficients sharply increased from 2.04 to 3.69 times of that in the inlet. The local mass transfer coefficients in each mixing group had unimodal profiles.

Henry's constants and mass transfer coefficients of halogenated organic pollutants in an air stripping packed column

1998 ◽  
Vol 38 (6) ◽  
pp. 287-294 ◽  
Author(s):  
Pen-C. Chiang ◽  
Chung-H. Hung ◽  
J. C. Mar ◽  
E. E. Chang
Keyword(s):  
Mass Transfer ◽  
Methylene Chloride ◽  
Packed Column ◽  
Transfer Coefficients ◽  
Chlorinated Organic Compounds ◽  
Air Stripping ◽  
Mass Transfer Coefficients ◽  
Equilibrium Partition ◽  
Henry's Constants ◽  
Chlorinated Organic

Both Henry's constants and volumetric mass transfer coefficients (KLa) of eight priority chlorinated organic compounds including 1,1-dichloroethene, methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and 1,4-dichlorobenzene in an air stripping packed column were investigated in this study. The liquid and gas phase EPICS (Equilibrium Partition in Closed System) and direct calculating methods were applied to determine the Henry's constants of VOCs. The interference of co-solute on Henry's constants was also investigated. Experimental results indicated that decrease in Henry's constants of VOCs was observed in the presence of humic acid but no apparent effect on Henry's constants was detected when there was NaCl and surfactant in solution. Four different configurations of packing media including Intalox Saddle, Super Intalox Saddle, Telleret, and Hedgehog made of polypropylene were respectively packed in the air stripping tower and investigated in the study. The dependence of hydraulic loading, air-water ratio, and configurations of packing media on mass transfer coefficients of VOCs was discussed.

scholarly journals Heat Transfer in Rotating Serpentine Passages With Trips Normal to the Flow

1992 ◽  
Vol 114 (4) ◽  
pp. 847-857 ◽  
Author(s):  
J. H. Wagner ◽  
B. V. Johnson ◽  
R. A. Graziani ◽  
F. C. Yeh
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Large Scale ◽  
Flow Direction ◽  
Operating Conditions ◽  
Transfer Model ◽  
Transfer Coefficients ◽  
Flow Equations ◽  
Turbine Blade Cooling ◽  
Heat Transfer Coefficients

Experiments were conducted to determine the effects of buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. The experiments were conducted with a large-scale, multipass, heat transfer model with both radially inward and outward flow. Trip strips on the leading and trailing surfaces of the radial coolant passages were used to produce the rough walls. An analysis of the governing flow equations showed that four parameters influence the heat transfer in rotating passages: coolant-to-wall temperature ratio, Rossby number, Reynolds number, and radius-to-passage hydraulic diameter ratio. The first three of these four parameters were varied over ranges that are typical of advanced gas turbine engine operating conditions. Results were correlated and compared to previous results from stationary and rotating similar models with trip strips. The heat transfer coefficients on surfaces, where the heat transfer increased with rotation and buoyancy, varied by as much as a factor of four. Maximum values of the heat transfer coefficients with high rotation were only slightly above the highest levels obtained with the smooth wall model. The heat transfer coefficients on surfaces where the heat transfer decreased with rotation, varied by as much as a factor of three due to rotation and buoyancy. It was concluded that both Coriolis and buoyancy effects must be considered in turbine blade cooling designs with trip strips and that the effects of rotation were markedly different depending upon the flow direction.

Packed Tower Air Stripping – An Economical Alternative for Meeting California's Stringent THM Limits

2011 ◽  
Vol 2011 (15) ◽  
pp. 1869-1889
Author(s):  
Katy Rogers ◽  
Michael Britten ◽  
Michael Hartlaub ◽  
Peter von Bucher
Keyword(s):  
Air Stripping ◽  
Packed Tower ◽  
Economical Alternative

Second Law Analysis of Solid Desiccant Rotary Dehumidifiers

1988 ◽  
Vol 110 (1) ◽  
pp. 2-9 ◽  
Author(s):  
E. Van den Bulck ◽  
S. A. Klein ◽  
J. W. Mitchell
Keyword(s):  
Local Maximum ◽  
Operating Conditions ◽  
Second Law ◽  
Transfer Coefficients ◽  
Adiabatic Flow ◽  
Transfer Processes ◽  
Air Stream ◽  
Second Law Analysis ◽  
Pass Through ◽  
Air Streams

This paper presents a second law analysis of solid desiccant rotary dehumidifiers. The equations for entropy generation for adiabatic flow of humid air over a solid desiccant are developed. The generation of entropy during operation of a rotary dehumidifier with infinite transfer coefficients is investigated and the various sources of irreversibility are identified and quantified. As they pass through the dehumidifier, both the process and regeneration air streams acquire nonuniform outlet states, and mixing both of these air streams to deliver homogeneous outlet streams is irreversible. Transfer of mass and energy between the regeneration air stream and the desiccant matrix occurs across finite differences in vapor pressure and temperature and these transfer processes generate entropy. The second law efficiency of the dehumidifier is given as a function of operating conditions and the effect of finite transfer coefficients for an actual dehumidifier is discussed. It is shown that operating the rotary dehumidifier at conditions that minimize regeneration energy also yields a local maximum for the second law efficiency.

Gas Cooling and Humidification: Design of Packed Towers from Small-Scale Tests

1950 ◽  
Vol 163 (1) ◽  
pp. 41-53 ◽  
Author(s):  
W. F. Carey ◽  
G. J. Williamson
Keyword(s):  
Operating Conditions ◽  
Total Heat ◽  
Small Scale ◽  
Water Cooling ◽  
Packed Tower ◽  
Simple Method ◽  
Worked Example ◽  
Gas Cooling ◽  
Heat Method ◽  
Working Out

On plants in which gases are processed, the gases are often brought into direct contact with water—usually in packed towers. The purpose may be to cool a hot gas, to increase the humidity of a gas, or, in the well-known special case of water-cooling towers, to cool water by contact with atmospheric air. These processes involve simultaneous transfers of sensible heat and water vapour, and existing methods of analysis are complex and laborious, except for the cooling of water, for which Merkel's total-heat method has long been available. Merkel's approximate solution offers the engineer a simple method of working out, for any operating conditions, the amount of heat transferred and the “driving force” available for transferring it. The present paper generalizes the total-heat method and, with a permissible sacrifice in accuracy, preserves the essential simplicity of the water-cooling treatment for gas-cooling and humidification processes. To complete the design of a packed tower, a knowledge is required of the characteristics of the packing. Information obtained in small towers is given for a number of packings, and a worked example shows how to apply the method of treatment, and the packing data presented, to the design of a large plant tower.

scholarly journals The ideological use and abuse of Freiburg’s ordoliberalism

Public Choice ◽  
2021 ◽  
Author(s):  
Malte Dold ◽  
Tim Krieger
Keyword(s):  
Dynamic Game ◽  
Academic Discourse ◽  
The Political ◽  
Eurozone Crisis ◽  
Economic Problems ◽  
Self Interest ◽  
Active Research ◽  
Active Research Program ◽  
Policy Proposals ◽  
Freiburg School

AbstractIn the aftermath of the Eurozone crisis, a battle of ideas emerged over whether ordoliberalism is part of the cause or the solution of economic problems in Europe. While German ordoliberals argued that their policy proposals were largely ignored before, during and after the crisis, critics saw too much ordoliberal influence, especially in form of austerity policies. We argue that neither view is entirely correct. Instead, we observe that the battle of ideas is largely independent of the countries’ actual responses to the Eurozone crisis: pragmatic self-interest on behalf of governments rather than their ideological convictions played a crucial role in political reactions. We explain this dynamic game-theoretically and highlight a number of reasons for the decoupling of the political-pragmatic debate from the ideological-academic discourse. In addition, we argue that ordoliberals themselves contributed to the ideological misuse of their own program: the ordoliberal Freiburg School ceased to be an active research program and instead grew to resemble a tradition which all too often disregarded the international academic discourse, in particular in macroeconomics. As a result, ordoliberal thinking was abused by its proponents and critics alike to emphasize their preconceived Weltanschauung (worldview). We end our paper with some thoughts on how a contemporary ordoliberalism can be constructively used to react to some of the challenges of the ongoing Eurozone crisis.

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