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1

The steady-state and dynamic analysis of packed distillation column based on partial differential approach  

Microsoft Academic Search

The steady-state and dynamic behavior of a binary packed distillation column has been simulated using the two film back-mixing model. The model solution has been obtained employing orthogonal collocation on finite elements. The approach using the Legendre or Jacobi polynomial has been tested on the solution of related models. A pilot plant scaled packed distillation column distilling methanol-water mixture was

S. Karacan; Y. Cabbar; M. Alpbaz; H. Hapo?lu

1998-01-01

2

Utilization of Structured Packing for Energy Savings in Distillation and Absorption Columns  

E-print Network

gauze structured packings and the F1exipac@ or Me11apak sheetmeta1 structured packings have been widely applied in literally thousands of fractionation columns in the general chemical and specialty chemical areas, particularly for vacuum... gauze structured packings and the F1exipac@ or Me11apak sheetmeta1 structured packings have been widely applied in literally thousands of fractionation columns in the general chemical and specialty chemical areas, particularly for vacuum...

Berven, O. J.; Howard, W. E.

3

Energy Saving in Distillation Using Structured Packing and Vapor Recompression  

E-print Network

"Distillation is a big consumer of energy in process plant operations. A first step to energy cost savings is the use of high efficiency structured packing in place of trays or dumped packings in conventionally operated distillation columns. Larger...

Hill, J.H.

4

Separation of high-boiling petroleum distillates using gradient elution through dual-packed (silica gel-alumina gel) adsorption columns  

Microsoft Academic Search

The Bureau of Mines has developed a chromatographic separation procedure using a single dual-packed adsorption column containing silica gel and alumina that will separate high-boiling petroleum distillates into four concentrates: saturates, monoaromatics, diaromatics, and polyaromatics-polar. Spectral, adsorption, and radiotracer data indicate that the concentrates produced are predominantly as labeled. Subdividing the aromatics into major aromatic types greatly simplifies subsequent separation

D. E. Hirsch; R. L. Hopkins; H. J. Coleman; F. O. Cotton; C. J. Thompson

1972-01-01

5

ITER relevant testing of a cryogenic distillation column system  

Microsoft Academic Search

A new experimental system has been constructed to test ITER relevant distillation columns and related cryogenic distillation (CD) hardware and control systems. These columns are used to purify tritium in the ITER fuel cycle. The ITER test column reported here has a diameter of about 30 mm and a packed length of approximately 150 cm. It can operate with a

D. G. Bellamy; J. R. Robins; K. B. Woodall; S. K. Sood; P. Gierszewski

1995-01-01

6

Porosity distribution in random packed columns by gamma ray tomography  

Microsoft Academic Search

Gamma ray tomography experiments have been carried out to detect any spatial patterns in the porosity in a 0.6 m diameter packed column. Three different sizes of stainless steel Pall rings (16, 25 and 38 mm) have been examined. The primary objective is to detect spatial patterns and statistical information on porosity variation in packed distillation columns. Such data are

Zhongcheng Wang; Artin Afacan; K. Nandakumar; Karl T. Chuang

2001-01-01

7

Optimal design of thermally coupled distillation columns  

Microsoft Academic Search

This paper considers the optimal design of thermally coupled distillation columns and dividing wall columns using detailed column models and mathematical optimization. The column model used is capable of describing both conventional and thermally coupled columns, which allows comparisons of different structural alternatives to be made. Possible savings in both operating and capital costs of up to 30% are illustrated

G. Duennebier; Constantinos C. Pantelides

1999-01-01

8

Heat Exchanger Technologies for Distillation Columns  

E-print Network

Heat Exchanger Technologies for Distillation Columns G.T.Polley Pinchtechnology.com In this paper we look at the challenges that improvements in energy efficiency of distillation systems presents the heat exchanger designer. We examine... condensate sub-cooling. So, if this condensate subsequently requires re-heating both energy and capital have been wasted. If the condensate forms a feed to another distillation column it results in increased energy consumption if that separation...

Polley, G. T.

9

A new fully thermally coupled distillation column with postfractionator  

Microsoft Academic Search

For the improvement of distillation column efficiency, a new system of a fully thermally coupled distillation column is proposed and its performance is examined with two industrial processes. The system has an extra column called postfractionator and attached to the main column of an original fully thermally coupled distillation column.The outcome of performance investigation indicates that a 29% energy saving

Young Han Kim

2006-01-01

10

Using thermally coupled reactive distillation columns in biodiesel production  

Microsoft Academic Search

Production of methyl dodecanoate (biodiesel) using lauric acid and methanol with a solid acid catalyst of sulfated zirconia is studied by using two distillation sequences. In the first sequence, the methanol recovery column follows the reactive distillation column. In the second sequence, the reactive distillation and methanol recovery columns are thermally coupled. Thermally coupled distillation sequences may consume less energy

Nghi Nguyen; Ya?ar Demirel

2011-01-01

11

The Scaleup of Structured Packing from Distillation Pilot Plant Testing to Commercial Application  

E-print Network

in the process industry for increased efficiency, greater capacity, and energy savings in distillation columns. Pilot plant testing of the actual chemical system using commercially available structured packing is invaluable, but years of experience in pilot... pilot plant test in order to determine exactly how the process wi 11 respond to the use of hi gh efficiency, low pressure drop packings. Pilot plant testing of the actual chemical system using commercially available structured packing is invaluable...

Berven, O. J.; Ulowetz, M. A.

12

Analysis of finishing reactive distillation columns  

SciTech Connect

In this paper, a novel method to deal with the design and the synthesis of finishing reactive distillation columns with one reactive core, two rectifying sections, and one stripping section is presented. The attention of the work is concentrated on three subjects: (1) the feasibility of a given separation at both finite and total reflux operation; (2) the minimum energy demand operation; (3) the distribution of the reaction between the reactor and the finishing reactive column. The design problem presents the same grade of difficulty as that found in the design of conventional extractive columns. A geometric based method is used to explain key features of reactive distillation. Here, the relation between the reaction yield and the distillate flow rate plays a role similar to that of the entrainer flow in extractive distillation. Hence, special attention is given to the behavior of the profiles inside the rectifying section below the reactive core. The methodology is illustrated using the well-known MTBE case study.

Espinosa, J.; Aguirre, P.; Frey, T.; Stichlmair, J. [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl A fuer Verfahrenstechik] [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl A fuer Verfahrenstechik

1999-01-01

13

A Versatile, Automatic Chromatographic Column Packing Device  

ERIC Educational Resources Information Center

Describes an inexpensive apparatus for packing liquid and gas chromatographic columns of high efficiency. Consists of stainless steel support struts, an Automat Getriebmotor, and an associated three-pulley system capable of 10, 30, and 300 rpm. (MLH)

Barry, Eugene F.; And Others

1977-01-01

14

Final Report, Distillation Column Flooding Predictor  

SciTech Connect

The Flooding Predictor is an advanced process control strategy comprising a patented pattern-recognition methodology that identifies pre-flood patterns discovered to precede flooding events in distillation columns. The grantee holds a U.S. patent on the modeling system. The technology was validated at the Separations Research Program, The University of Texas at Austin under a grant from the U. S. Department of Energy, Inventions & Innovation Program. Distillation tower flooding occurs at abnormally high vapor and/or liquid rates. The loss in tray efficiencies is attributed to unusual behavior of liquid inventories inside the column leading to conditions of flooding of the space in between trays with liquid. Depending on the severity of the flood condition, consequences range from off spec products to equipment damage and tower shutdown. This non-intrusive pattern recognition methodology, processes signal data obtained from existing column instrumentation. Once the pattern is identified empirically, it is modeled and coded into the plant's distributed control system. The control system is programmed to briefly "unload" the tower each time the pattern appears. The unloading takes the form of a momentary reduction in column severity, e.g., decrease bottom temperature, reflux or tower throughput. Unloading the tower briefly at the pre-flood state causes long-term column operation to become significantly more stable - allowing an increase in throughput and/or product purity. The technology provides a wide range of value between optimization and flooding. When a distillation column is not running at capacity, it should be run in such a way ("pushed") that optimal product purity is achieved. Additional benefits include low implementation and maintenance costs, and a high level of console operator acceptance. The previous commercial applications experienced 98% uptime over a four-year period. Further, the technology is unique in its ability to distinguish between different flooding mechanisms within the same tower, e.g., liquid and jet flooding.

George E. Dzyacky

2003-05-31

15

Packed capillary columns for liquid chromatography  

Microsoft Academic Search

Summary  Fused silica capillaries, ? 130 ? 0.32mm have been packed with small reversed phase spherical silica particles, 3 or 2?m,\\u000a in order to achieve LC-systems giving high plate numbers at relatively low pressure drop in short analysis times. At optimal\\u000a conditions, columns packed with 3?m particles showed reduced plate heights, h, around 2.5, and the column flow resistance,\\u000a ?, was

S. Hoffmann; L. Blomberg

1987-01-01

16

Pressure drop effects in packed capillary column supercritical fluid chromatography  

Microsoft Academic Search

The subject of column pressure drop has generated much controversy when using packed columns in supercritical fluid chromatography (SFC), since packed columns usually exhibit a ssignificant pressure drop along the column. In this paper, the effect of pressure drop on the chromatographic behavior of capillary columns packed with small spherical silica particles in SFC was studied using neat carbon dioxide

Wenbao Li; Abdul Malik; Milton L. Lee

1997-01-01

17

COLLOCATION METHODS FOR DISTILLATION DESIGN III: FLEXIBLE COLUMN DESIGN  

Microsoft Academic Search

In this third paper on collocation methods for distillation design, we explore the use of the collocation models for design of simple distillation columns as well as flexible columns. Solvent recovery plants must deal with a wide range of feeds and still return pure solvents. The design problem we address is a single flexible column within the overall solvent recovery

Robert S. Huss; Arthur W. Westerberg

18

Research on Configurations of Thermally Integrated Distillation Column(TIDC)  

Microsoft Academic Search

\\u000a Taking a C3 distillation column as the base case, possible configurations for Thermally Integrated Distillation Columns (TIDC)\\u000a are proposed and compared to a conventional column and a column with a vapor recompression system (VRC). Thermal efficiency\\u000a of the TIDC appears to be strongly sensitive to column configuration and a highly efficient asymmetrical configuration with\\u000a stripping section stages thermally interconnected with

Lanyi Sun; Jun Li; Xuenuan Liu; Qingsong Li

2011-01-01

19

Small scale ethanol production demonstration: comparison of packed versus plate rectifying column  

SciTech Connect

The Johnson Environmental and Energy Center with assistance from the Madison County Farm Bureau Association received a grant in 1980 from the US Department of Energy to design, fabricate, and evaluate a small scale continuous ethanol plant. In 1981, the Center received a second DOE grant to compare the economics of replacing the plate rectifying column in the initial unit with a packed rectifying column. The results of the study indicate that the distillation unit with the packed rectifying column is capable of producing 14 gallons per hour of 170 proof ethanol. The energy ratio for distillation was a positive 2:1. Cost of the packed column was considerably less than the plate column. 1 reference, 19 figures, 9 tables.

Adcock, II, L E; Eley, M H; Schroer, B J

1982-07-01

20

Are thermally coupled distillation columns always thermodynamically more efficient for ternary distillations?  

Microsoft Academic Search

The thermodynamic efficiency of five ternary distillation configurations to distill ideal saturated liquids into pour product streams are calculated and compared. A striking result of this study is that for the fully coupled column (Petlyuk) configuration, which is known to have the lowest heat demand for ternary distillation, the range of values of feed composition and relative volatilities for which

Rakesh Agrawal; Zbigniew T. Fidkowski

1998-01-01

21

Energy savings in heat-integrated distillation columns  

Microsoft Academic Search

The heat-integrated distillation column (HIDiC) provides one of the most effective applications of heat-pump technologies to industrial processes. It reinforces a separation process and yields larger energy savings than other methods such as overhead-to-reboiler heat pumps, which involve moving heat between the hottest and coldest points in the distillation column. A simulation study of this column has been applied to

M. Nakaiwa; K. Huang; M. Owa; T. Akiya; T. Nakane; M. Sato; T. Takamatsu

1997-01-01

22

Future perspectives of using hollow fibers as structured packings in light hydrocarbon distillation  

SciTech Connect

Olefin and paraffin are the largest chemical commodities. Furthermore, they are major building blocks for the petrochemical industry. Each year, petroleum refining, consumes 4,500 TBtu/yr in separation energy, making it one of the most energy-intensive industries in the United States). Just considering liquefied petroleum gas (ethane/propane/butane) and olefins (ethylene and propylene) alone, the distillation energy consumption is about 400 TBtu/yr in the US. Since petroleum distillation is a mature technology, incremental improvements in column/tray design will only provide a few percent improvements in the performance. However, each percent saving in net energy use amounts to savings of 10 TBtu/yr and reduces CO{sub 2} emissions by 0.2 MTon/yr. In practice, distillation columns require 100 to 200 trays to achieve the desired separation. The height of a transfer unit (HTU) of conventional packings is typical in the range of 36-60 inch. Since 2006, we had explored using several non-selective membranes as the structured packings to replace the conventional packing materials used in propane and propylene distillation. We obtained the lowest HTU of < 8 inch for the hollow fiber column, which was >5 times shorter than that of the conventional packing materials. In 2008, we also investigated this type of packing materials in iso-/n-butane distillation. Because of a slightly larger relative volatility of iso-/n-butane than that of propane/propylene, a wider and a more stable operational range was obtained for the iso-/n-butane pair. However, all of the experiments were conducted on a small scale with flowrate of < 25 gram/min. Recently, we demonstrated this technology on a larger scale (<250 gram/min). Within the loading range of F-factor < 2.2 Pa{sup 0.5}, a pressure drop on the vapor side is below 50 mbar/m, which suggests that the pressure drop of hollow fibers packings is not an engineering barrier for the applications in distillations. The thermal stability study suggests that polypropylene hollow fibers are stable after a long time exposure to C{sub 2} - C{sub 4} mixtures. The effects of packing density on the separation efficiency will be discussed.

Yang, Dali [Los Alamos National Laboratory; Orler, Bruce [Los Alamos National Laboratory; Tornga, Stephanie [Los Alamos National Laboratory; Welch, Cindy [Los Alamos National Laboratory

2011-01-26

23

Fraction Collector for Distillation Columns Operating at Reduced Pressure  

Microsoft Academic Search

A fraction collector for distillation columns operating at reduced pressure is described. With the apparatus, fractions of known volume can be automatically collected in collecting vessels closed with serum caps under controlled atmosphere or under vacuum. The collecting vessels are accessible at all times for further analysis of the distillate. The design is based on the use of a piston

M. Van Swaay

1964-01-01

24

Operation behaviors of ideal internal thermally coupled distillation columns  

Microsoft Academic Search

A lack of experience in operation is one of the major difficulties associated with the use of advanced energy saving distillation\\u000a methods. The detailed operational studies of an ideal internal thermally coupled distillation column (ITCDIC) were carried\\u000a out in this work paved the way for further control and design studies and its practical application.

Liu Xin-gao; Qian Ji-xin; Xu Yong-mao

2000-01-01

25

Optimal energy cost in ideal internal thermally coupled distillation columns  

Microsoft Academic Search

Internal thermally coupled distillation column (ITCDIC) is the frontier of energy saving distillation research. In the paper, an evaluation method on operating cost and its saving in the ITCDIC processes of ideal mixtures is presented. A mathematical model for optimization is first derived. The benzene-toluene system is studied as an illustrative example. The optimization results show that the energy cost

Xinggao Liu; Yongmao Xu; Jie Zhang; Jixin Qian

2002-01-01

26

Application of a thermally coupled distillation column with separated main columns to gas concentration process  

Microsoft Academic Search

A modified fully thermally coupled distillation column (FTCDC) for operability improvement is utilized in a gas concentration\\u000a process. The column consists of a prefractionator and two separated main columns having high distillation efficiency and flexible\\u000a control structure. The operability of the proposed column is evaluated by examining the open-loop dynamic responses of step\\u000a input variations with the HYSYS simulation. The

Moon Yong Lee; Su Yeung Jeong; Young Han Kim

2008-01-01

27

Determination of plate efficiencies for conventional distillation columns  

E-print Network

DETERMINATION OF PLATE EFFICIENCIES FOR CONVENTIONAL DISTILLATION COIUMNS A Thesis By Thomas Raymond Harris Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 1962 Ma)or Sub)ect t Chemical Engineering DETERMINATION OF PLATE EFFICIENCIES FOR CONVENTIONAL DISTILLATION COLUMNS A Thesis Thomas Raymond Harris Approred as to style and content bye Chairman of ommittee Head...

Harris, Thomas Raymond

2012-06-07

28

Perfusion chromatography — characterization of column packings for chromatography of proteins  

Microsoft Academic Search

A Van Deemter equation modeling columns packed with spherical monodisperse perfusive media was utilized to calculate the predicted values of the effective pore diffusivity (Dp) and split ratio (?) of columns packed with POROS® and Oligo R3™ media. The validity of the model was established by calculating consistent values of Dp and ? for lysozyme, ?-chymotrypsinogen A and IgG using

Mark McCoy; Krishna Kalghatgi; Fred E. Regnier; Noubar Afeyan

1996-01-01

29

Kinetic azeotropy and design of reactive distillation columns  

SciTech Connect

The reactive fixed points in the distillation maps of a reactive distillation column (RDC) with kinetically controlled reactions are identified and their role in deciding the design feasibility has been elucidated. The fixed points at which both reaction and distillation vectors have zero magnitudes correspond to the equilibrium fixed point. It is known that the relative positions of these points for the rectifying and stripping sections determine the value of the minimum reflux ratio. However, apart from these fixed points, there are certain fixed points in the distillation map at which, though the reaction and distillation vectors have nonzero magnitudes, they nullify the effects of each other. These points correspond to the kinetic fixed points and have a special significance. Their positions have direct influence on the feasible product composition. A simple example of an ideal ternary system undergoing a reaction 2B {longleftrightarrow} A + c has been illustrated to show the importance of kinetic azeotropy in the design aspects of RDC.

Mahajani, S.M. [Monash Univ., Clayton, Victoria (Australia). Dept. of Chemical Engineering] [Monash Univ., Clayton, Victoria (Australia). Dept. of Chemical Engineering

1999-01-01

30

Approximate design of fully thermally coupled distillation columns  

Microsoft Academic Search

An approximate design procedure for fully thermally coupled distillation columns (FTCDCs) is proposed and applied to example\\u000a ternary systems. The procedure gives a fast solution of structural and operation design for a preliminary study of the FTCDC.\\u000a The structural information resolves the design difficulty, caused from the interlinking streams of the column, which is encountered\\u000a when a conventional design procedure

Young Han Kim; Masaru Nakaiwa; Kyu Suk Hwang

2002-01-01

31

CONTROL CONFIGURATION SELECTION FOR DISTILLATION COLUMNS UNDER TEMPERATURE CONTROL  

E-print Network

CONTROL CONFIGURATION SELECTION FOR DISTILLATION COLUMNS UNDER TEMPERATURE CONTROL Erik A. Wol#11; and Sigurd Skogestad #3; University of Trondheim N-7034 Trondheim, NORWAY Keywords: process control, cascade control, distilla- tion, control structure, relative gain array 1 Introduction In most process control

Skogestad, Sigurd

32

PROCESS DESIGN AND CONTROL Temperature Cascade Control of Distillation Columns  

E-print Network

main objectives for the regulatory control system are as follows: 1. Take care of control tasks where control. This is because the main control objective at this level is to facilitate good operation, that isPROCESS DESIGN AND CONTROL Temperature Cascade Control of Distillation Columns Erik A. Wolff

Skogestad, Sigurd

33

Rigorous design of extended fully thermally coupled distillation columns  

Microsoft Academic Search

An approximate design procedure of extended fully thermally coupled distillation columns (FTCDCs) is refined for the design of real system having non-ideal equilibrium relation. For high thermodynamic efficiency and reduced computational load, a structural design utilizing the minimum tray structure is implemented, and the design procedure to find operational variables for a given specification of products is explained in detail.

Young Han Kim

2002-01-01

34

Packed capillary column solvating gas chromatography of aldehydes  

Microsoft Academic Search

The rapid separation of aldehydes of environmental interest was investigated using packed capillary column solvating gas chromatography (SGC). Fused-silica capillary columns (250 ?m I.D.) were packed with poly(dicyanoallylsiloxane)-encapsulated 10 ?m spherical porous (80 Å) silica particles. Excellent resolution and good peak shapes were achieved for underivatized aldehydes using carbon dioxide as mobile phase. The effects of temperature and pressure on

Christopher R Bowerbank; Yufeng Shen; Philip A Smith; David B Drown; Milton L Lee

1998-01-01

35

Distillation column revamp eliminates jet flooding; increases efficiency  

SciTech Connect

UOP's McCook, IL, plant produces a great variety of chemicals, among them many antioxidants and antiozonants which are used by gasoline producers, rubber processors and other industrial customers. Low boiling oxygenated aliphatics are stripped from high boiling nitrogenous compounds in a distillation column. In order to achieve the necessary separation, very high column reflux rates were required. This sometimes caused jet flooding which led to entrainment and contamination of the overhead streams. When the overhead streams did not meet purity specs, they had to be inventoried and later recycled. The result was unacceptably high costs and low overall unit efficiency. To correct the problem, UOP decided to revamp the column in question. The 28 original sieve trays were removed from the 28' tall, 19 1/4'' ID column, and 27 SS304 cartridge-type fabricated screen trays were installed don 12'' spacing. The closely spaced wires from which the decks of the trays are fabricated form venturi-shaped slots that allow operation in the froth regime over a wide range of conditions. Reduced entrainment and low pressure drop combine to permit use of very high vapor and liquid rates without flooding. After the revamp, UOP found that flooding problems were eliminated in the column. Pressure drop was considerably reduced, too. An increase in separation efficiency was also noticed which permitted reboiler temperatures to be lowered by 20-50/sup 0/F, and lower reflux rates to be employed. Energy requirements of the reboiler were cut by 400,000 Btu/hr at 80% of maximum column feed rate. This represented a savings of more that $16,000/yr in fuel costs on an annualized basis, calculated on 80% efficiency in the natural gas-fired furnace.

Arneson, A.D.; Boike, J.

1986-10-01

36

Consolidation of the packing material in chromatographic columns under dynamic axial compression IV. Mechanical properties of some packing materials  

Microsoft Academic Search

Dynamic axial compression columns were packed with three C18 silica materials used as statinalry phases in preparative chromatography, one made of irregular and two of spherical particles. Measurements of column lenght vs. time and axial compression pressure, obtained for several columns, have been previously reported. These results are discussed here in terms of packing density, internal porosity, and external porosity,

Brett J. Stanley; Matilal Sarker; Georges Guiochon

1996-01-01

37

METHOD TO TEST ISOTOPIC SEPARATION EFFICIENCY OF PALLADIUM PACKED COLUMNS  

SciTech Connect

The isotopic effect of palladium has been applied in different ways to separate hydrogen isotopes for many years. At Savannah River Site palladium deposited on kieselguhr (Pd/k) is used in a thermal cycling absorption process (TCAP) to purify tritium for over ten years. The need to design columns for different throughputs and the desire to advance the performance of TCAP created the need to evaluate different column designs and packing materials for their separation efficiency. In this work, columns with variations in length, diameter and metal foam use, were tested using an isotope displacement method. A simple computer model was also developed to calculate the number of theoretical separation stages using the test results. The effects of column diameter, metal foam and gas flow rate were identified.

Heung, L; Gregory Staack, G; James Klein, J; William Jacobs, W

2007-06-27

38

Evaluation of Packed Columns in Supercritical Extraction Processes  

E-print Network

--------- EVALUATION OF PACKED COLUMNS IN SUPERCRITICAL EXTRACTION PROCESSES Paul J. Rathkamp, James R. Fair, Jimmy L. Humphrey The University of Texas at Austin Austin, Texas ABSTRACT The purpose of the present work is to add to the base...). From a process point of view conventional liquid-liquid and supercritical fluid extraction (SFE) are identical in that one or more components of a liquid solution are separated by contact with a second immiscible liquid called the solvent...

Rathkamp, P. J.; Fair, J. R.; Humphrey, J. L.

39

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components.  

DOEpatents

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Egorov, Oleg B. (Richland, WA); O'Hara, Matthew J. (Richland, WA); Grate, Jay W. (West Richland, WA); Chandler, Darrell P. (Richland, WA); Brockman, Fred J. (Kennewick, WA); Bruckner-Lea, Cynthia J. (Richland, WA)

2004-08-24

40

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components  

DOEpatents

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Egorov, Oleg B. (Richland, WA); O'Hara, Matthew J. (Richland, WA); Grate, Jay W. (West Richland, WA); Chandler, Darrell P. (Richland, WA); Brockman, Fred J. (Kennewick, WA); Bruckner-Lea, Cynthia J. (Richland, WA)

2006-02-21

41

Hydrodynamic impact of particle shape in slurry packed liquid chromatography columns  

Microsoft Academic Search

We report on a series of flow velocity and efficiency profiles, which were measured across the cross section of preparative chromatographic columns packed with different stationary phase materials using computed tomography. It is shown that this non-invasive technique is very useful for visualization of the inner part of a packed column and measurement of the spatial resolved column packing properties.

Florian Lottes; Wolfgang Arlt; Mirjana Minceva; Erling H. Stenby

2009-01-01

42

A SIMPLE ALGORITHM FOR THE DESIGN OF FULLY THERMALLY COUPLED DISTILLATION COLUMNS (FTCDC)  

Microsoft Academic Search

Although material and thermal coupling between the prefractionator and main distillation column renders the fully thermally coupled distillation column (FTCDC) a frequently favorable design option, it also complicates considerably process synthesis and design. In this contribution, a simple algorithm for the synthesis and design of the FTCDC is derived with the optimization of an economical objective function. In terms of

Peng Wang; Haisheng Chen; Yufeng Wang; Liang Zhang; Kejin Huang; San-Jang Wang

2012-01-01

43

A GENERALIZED DYNAMIC MODEL FOR DISTILLATION COLUMNS-III. STUDY OF STARTUP OPERATIONS  

Microsoft Academic Search

The dynamic behavior of distillation columns during startup operations have been studied and analyzed. A procedure is proposed for determining appropriate startup policies for distillation column operations based on the analysis of the dynamic behavior. The final startup policy consists of three strategies corresponding to the three characteristic stages of the startup operation. The proposed procedure has been successfully applied

C. A. Rurz; I. T. CAMERON; R. GANI

44

Minimum Energy Consumption in Multicomponent Distillation. 1. Vmin Diagram for a Two-Product Column  

E-print Network

Minimum Energy Consumption in Multicomponent Distillation. 1. Vmin Diagram for a Two-Product Column how the minimum energy consumption is related to the feed-component distribution for all possible operating points in a two-product distillation column with a multicomponent feed. The classical Underwood

Skogestad, Sigurd

45

Application of a fully thermally coupled distillation column for fractionation process in naphtha reforming plant  

Microsoft Academic Search

Naphtha reformate is extracted for aromatic compounds and the aromatics are separated into benzene, toluene and xylene in sequence. This separation is conducted using a series of binary-like columns.In this study, the first two columns of the separation process are replaced with a fully thermally coupled distillation column (FTCDC) also known as the Petlyuk column. Though feed of the process

Ju Yeong Lee; Young Han Kim; Kyu Suk Hwang

2004-01-01

46

High-purity control of internal thermally coupled distillation columns based on nonlinear wave model  

Microsoft Academic Search

Internal thermally coupled distillation column (ITCDIC) is a frontier of energy saving distillation researches, which is a great improvement on conventional distillation column (CDIC). However its high degree thermal coupling makes the control design a bottleneck problem, where data-driven model leads to obvious mismatch with the real plant in the high-purity control processes, and a first-principle model which is comprised

Xinggao Liu; Yexiang Zhou; Lin Cong; Feng Ding

2011-01-01

47

High Performance Liquid Chromatography Separations Using Short Columns Packed with Spherical and Irregular Shaped ODS Particles  

Microsoft Academic Search

In a comparative study of the separation of a mixture of polycyclic aromatic hydrocarbrons on 5 cm and 10 cm columns packed with 3? and 5? ODS spherical particles, the separations achieved on the 10 cm column were not significantly better than those on the 5 cm column. Although, columns packed with 3? ODS spherical particles gave slightly better resolution

Haleem J. Issaq; Robert E. Gourley

1983-01-01

48

Hydrodynamics of a packed countercurrent column for the gas extraction  

SciTech Connect

The hydraulic capacity of a countercurrent column with gauze packing was examined at pressures between 8 and 30 MPa and temperatures between 313 and 373 K. The systems used were water + carbon dioxide, aqueous surfactant solution + carbon dioxide, and Toco, a substance whose physical properties are roughly similar to those of {alpha}-Tocopherol + carbon dioxide. A distinctive change in the flooding mechanisms from liquid layer flooding to bubble column flooding was observed. The different liquids, water and Toco, showed the same flooding behavior, indicating that the influence of the density on the flooding behavior prevails over the influence of any other physical property of the liquid. The foamability of the surfactant solution decreased significantly with increasing pressure--its influence on the flooding behavior could not be proved. The liquid holdup ranged between 2% and 6%. The dry pressure drop adhered to the Ergun equation.

Stockfleth, R.; Brunner, G.

1999-10-01

49

Design of extraction column methanol recovery system for the TAME reactive distillation process  

Microsoft Academic Search

This paper studies the synthesis and the design of methanol recovery system for TAME reactive distillation process using extraction column with water as a solvent. The design of the extraction column system has not been studied in the literature. The effect of operating conditions such as solvent flowrate, extraction column temperature, and number of equilibrium trays are studied. It is

Muhammad A. Al-Arfaj

2004-01-01

50

The Production of Electrochromatography Capillary Columns Using Gas Pressure Powered Dry-Packing Method  

Microsoft Academic Search

This paper introduces a dry-packing method of producing packed capillaries for using in capillary electrochromatography (CEC) or microbore HPLC. Several C18 packing materials with different particle size are studied. We compared the two methods of dry-packing and slurry-packing. The former yields analogous or better efficiency with a simpler apparatus using a shorter packing time. Besides, the columns are very stable

Changqiao Zhang; Chenfu Zhu; Xiuli Lin; Yunhe Wei

2003-01-01

51

High Performance Trays and Heat Exchangers in Heat Pumped Distillation Columns  

E-print Network

Vapor recompression of distillation columns overheads, followed by subsequent condensation in the reboiler results in substantial operating cost savings compared to conventional steam driven reboiler systems. The use of high performance heat...

Wisz, M. W.; Antonelli, R.; Ragi, E. G.

1981-01-01

52

Reactive distillation–pervaporation hybrid column for tert-amyl alcohol etherification with ethanol  

Microsoft Academic Search

The etherification of tert-amyl alcohol with ethanol was carried out in a reactive distillation column inserted by a zeolite NaA membrane tube. Experimental tests were carried out in both of a pervaporation module and a reactive distillation column. Under suitable conditions, the pervaporation tests have shown higher than 99.9% H2O mole fraction in the permeate. The design by the residue

Farid Aiouache; Shigeo Goto

2003-01-01

53

Application of the theta method to distillation columns where one or more reactions occur per stage  

E-print Network

APPLICATION OF THE THETA METHOD TO DISTILLATION COLUMNS WHERE ONE OR MORE REACTIONS OCCUR PER STAGE A Thesis by ALICIA IZARRARAZ Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1979 Major Subject: Chemical Engineering APPLICATION OF THE THETA METHOD TO DISTILLATION COLUMNS WHERE ONE OR MORE REACTIONS OCCUR PER STAGE A Thesis by ALICIA IZARRARAZ Approved as to style and content by: cubi...

Izarraraz, Alicia

2012-06-07

54

A generalized model for distillation columns—I Model description and applications  

Microsoft Academic Search

AM-A generalized model for the dynamic simulation of distillation columns is presented. The model allows the solution of a wide variety of problems, from open- and closed-loop responses of single (and multiple) columns to operability studies (of feed changeover and start-up operations) and column instability studies (effect of plate hydraulics during transient operations). Results are given for single columns (including

R. GANI; I. T. CAMERONS

1986-01-01

55

Assessing Safety in Distillation Column Using Dynamic Simulation and Failure Mode and Effect Analysis (FMEA)  

NASA Astrophysics Data System (ADS)

Safety assessment becomes an important activity in chemical industries since the need to comply with general legal requirements in addition to meet safer plant and profit. This paper reviews some most frequently causes of distillation column malfunction. First, analysis of case histories will be discussed for providing guidelines in identifying potential trouble spots in distillation column. A dynamic simulation for operational failure is simulated as the basis for assessing the consequences. A case study will be used from a side stream distillation column to show the implementation of the concept. A framework for assessing safety in the column is proposed using Fault Mode and Effect Analysis (FMEA). Further, trouble-free operation in order to reduce the risk associated with column malfunction is described.

Werner, Suhendra; Fred, Witt; Compart

56

Catalytic distillation process  

DOEpatents

A method for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C.sub.4 feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

Smith, Jr., Lawrence A. (Bellaire, TX)

1982-01-01

57

Catalytic distillation process  

DOEpatents

A method is described for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C[sub 4] feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

Smith, L.A. Jr.

1982-06-22

58

Particle packed columns and monolithic columns in high-performance liquid chromatography-comparison and critical appraisal.  

PubMed

The review highlights the fundamentals and the most prominent achievements in the field of high-performance liquid chromatography (HPLC) column development over a period of nearly 50 years. After a short introduction on the structure and function of HPLC columns, the first part treats the major steps and processes in the manufacture of a particle packed column: synthesis and control of particle morphology, sizing and size analysis, packing procedures and performance characterization. The next section is devoted to three subjects, which reflect the recent development and the main future directions of packed columns: minimum particle size of packing, totally porous vs. core/shell particles and column miniaturization. In the last section an analysis is given on an alternative to packed columns-monolithic columns, which have gained considerable attraction. The challenges are: improved packing design based on modeling and simulation for targeted applications, and enhanced robustness and reproducibility of monolithic columns. In the field of miniaturization, particularly in chip-based nano-LC systems, monoliths offer a great potential for the separation of complex mixtures e.g. in life science. PMID:18177658

Unger, Klaus K; Skudas, Romas; Schulte, Michael M

2008-03-14

59

Structural design and operation of a fully thermally coupled distillation column  

Microsoft Academic Search

A rigorous structural design procedure for fully thermally coupled distillation columns (FTCDC) is applied to the example system of butanol isomers in order to show the design performance. The procedure gives structural information of the column, and therefore iterative computation encountered in the design using conventional procedure and commercial packages can be eliminated.Using the outcome of the structural design, other

Young Han Kim

2002-01-01

60

Optimal Allocation of Heat Exchanger Inventory in a Serial Type Diabatic Distillation Column  

E-print Network

Optimal Allocation of Heat Exchanger Inventory in a Serial Type Diabatic Distillation Column Edward the column . We have previously shown (Jimenez et al. 2003) that optimaloperation of serial heat exchangers total heat exchanger area in different trays and calculate the optimal allocation of a given heat

Salamon, Peter

61

Consolidation of the packing material in Chromatographic columns under dynamic axial compression II. Consolidation and breakage of several packing materials  

Microsoft Academic Search

The consolidation of packing materials under dynamic axial compression is studied for one irregular and two spherical shaped particles. When the total axial compression stress is raised from 1 to 80 kg\\/cm2, a long column of initial length 25 cm shrinks by nearly 25%, while a short column of initial length 4 cm decreases by nearly 35%. This result illustrates

Matilal Sarker; Anita M. Katti; Georges Guiochon

1996-01-01

62

Consolidation and column performance of several packing materials for liquid chromatography in a dynamic axial compression column  

Microsoft Academic Search

The mechanical properties of four different packing materials for preparative liquid chromatography were investigated. Their compression kinetics and consolidation behavior were measured under dynamic compression stress in a 5-cm I.D. axial compression column. The internal and external porosities, the packing density, the permeability, and the efficiency of these columns were also measured. The materials studied included two spherical silica-based materials

Joon-Ho Koh; B. Scott Broyles; Hong Guan-Sajonz; Michael Z.-C Hu; Georges Guiochon

1998-01-01

63

Practical Application of Distillation Column Energy Control Systems  

E-print Network

Closed loop computer control of an ethylene column has been shown to save $350/day in improved ethylene recovery and $150/day in reduced energy consumption. These savings are achieved through material balance optimization and energy balance...

Matthews, S. A.

1980-01-01

64

Integrated Thermal and Hydraulic Analysis of Distillation Columns  

E-print Network

by assuming that the equilibrium and operating lines coincide at this stage. This approximation takes into account the losses or inefficiencies introduced through practicalities of column design (such as pressure drops, multiple side-products, side strippers... (heating or cooling) ? Side condensing or reboiling An additional capability is provided through exergy analysis. The exergy profiles are plotted by calculating the exergy loss at each stage of the column, and then taking into account all entering...

Samant, K.; Sinclair, I.; Keady, G.

65

Performance evaluation of slurry-packed capillary columns for liquid chromatography  

Microsoft Academic Search

Summary  Fused-silica capillary columns with 200 m internal diameter were efficiently packed with both 3 m and 5 m spherical C18 bonded-phase particles. Optimum packing conditions were determined and column performance was then critically evaluated in terms of the reduced plate height as a function of both reduced velocity and solute capacity factor. Characteristic values for various column performance indices, such

J. C. Gluckman; A. Hirose; V. L. McGuffin; M. Novotny

1983-01-01

66

Effect of the column length on the characteristics of the packed bed and the column efficiency in a dynamic axial compression column  

Microsoft Academic Search

The axial homogeneity of preparative-scale chromatography columns was studied by measuring the overall properties of similar columns differing only by their lengths. The properties investigated were the packing density, the external porosity, the permeability and the column efficiency. Two different materials were used, one made of large, irregular silica particles compressed under either a high or a low degree of

Joon-Ho Koh; Georges Guiochon

1998-01-01

67

Calculational procedure for multicomponent distillation columns with side-stream-strippers  

E-print Network

to be uved only where the oorrect values of V and I crc not known in advance. Again for tbe case under consideration, v -" 0 for all plates in ths $1 distillation column below and including the side-stream withdrawal plate, Also, 1 = 0 for all the plates... to be uved only where the oorrect values of V and I crc not known in advance. Again for tbe case under consideration, v -" 0 for all plates in ths $1 distillation column below and including the side-stream withdrawal plate, Also, 1 = 0 for all the plates...

Dickey, Billy Ray

2012-06-07

68

Pseudo-electrokinetic packing of high efficiency columns for capillary electrochromatography.  

PubMed

An improved and easy electrokinetic packing procedure is presented for the production of stable capillary columns suitable for capillary electrochromatography (CEC). In pseudo-electrokinetic packing a high electric field is used in conjunction with a hydrodynamic flow. The packing of silica-based reversed-phase columns can be achieved with basic, commercially available capillary electrophoresis (CE) equipment in approximately 15 min. The procedure is robust and a high success rate is achieved. No steps which might damage the stationary phase are involved and only a minimum amount of packing material is required. Columns packed according to the developed procedure are operated at high electric field strengths during the CEC separation, without the application of a stabilising pressure. Columns are stable for at least hundred runs and were tested using mixtures of polycyclic aromatic hydrocarbons and positively charged drugs. Separations were performed in a relatively high conducting ammonium acetate buffer, with efficiencies of up to 283000 plates/m. PMID:10757307

Stol, R; Mazereeuw, M; Tjaden, U R; van der Greef, J

2000-03-24

69

Distillation of a Complex Mixture. Part II: Performance Analysis of a Distillation Column Using Exergy  

NASA Astrophysics Data System (ADS)

To analyze the performance of the separation process, we have introduced thethermodynamic concept of exergy through the exergetic efficiency of the column. Thesimulation results show that the exergetic output is relatively low and that the producedirreversibility fluxes are distributed throughout the whole column in a non-uniform manner.They are particularly significant in the condenser, boiler and tray feed. The influence of thevarious operating parameters (temperature, concentration and irreversibility in both sectionsof the column) is also established. To emphasize the results, the relation in equation 17, ispresented graphically to evaluate the cumulative irreversibilities from the overhead to thebottom. This presentation is equivalent to the Grassmann diagram.

Mustapha, Douani; Sabria, Terkhi; Fatima, Ouadjenia

2007-09-01

70

Hydrodynamics and mass transfer coefficients for a modified Raschig ring packed column  

NASA Astrophysics Data System (ADS)

The pressure drop, the liquid holdup, as well as the liquid film mass transfer coefficients (kL) for a modified Raschig packing, with turbulence promoters, used in absorption columns, were determined experimentally. The aim of this work is to verify the improved mass transfer properties of this new packing for the randomly and, particularly, for the arranged packed columns. The experiments were performed at gas velocities ranging from 800 to 2,000 m h-1 and liquid velocities scaling between 2.5 and 8.11 m h-1, ranges that cover most of the absorption column operation conditions. Experimental data and correlations for the pressure drop, the liquid holdup and the gas-liquid mass transfer coefficients (kL) for modified Raschig ring packed columns are presented. The influence of the gas and the liquid velocities on the column hydrodynamics and the mass transfer coefficients have been obtained experimentally and also, have been compared with literature data.

Mamaliga, I.; Sidor, D.; Condurat, C.; Iacob Tudose, E. T.

2014-10-01

71

Design of a fully thermally coupled distillation column based on dynamic simulations  

Microsoft Academic Search

A dynamic simulation of a fully thermally coupled distillation column is conducted for the design of a possible operation\\u000a scheme, and its performance is examined with an example process of butanol isomer ternary system. The outcome of the dynamic\\u000a simulation indicates that the column can be operated by using a 3 ? 3 control structure. The structure consists of three

Young Han Kim

2000-01-01

72

Development of a Fritless Packed Column for Capillary Electrochromatography-Mass Spectrometry  

PubMed Central

A novel procedure was developed for the fabrication of a fritless packed column for the coupling of capillary electrochromatography (CEC) to mass spectrometry (MS). The process involved the formation of internal tapers on two separate columns. Once the internal tapers are formed and the columns are packed, the untapered ends of each column were joined together by a commercially available connector. Several advantages of the fritless columns are described. First, the design used here eventually eliminates the need for any frits thus reducing the possibility of bubble formation seen with fritted packed columns. In addition, this is the first report in which the internal tapers are formed at both the inlet and outlet column ends making the fritless CEC-MS column more robust compared to only one report with externally tapered counterparts. Second, a comparison of internally tapered single frit packed CEC-MS (previously developed in our laboratory) column versus fritless CEC-MS column reported here shows that the latter provides better efficiency, suggesting no dead volume with equally good sensitivity and chiral resolution of (±)-aminoglutethimide. The fritless column procedure is universal and was used to prepare a series of columns with a variety of commercially available packing material (mixed mode strong cation exchange, SCX; mixed mode strong anion exchange, SAX; C-18) for the separation and MS detection of short chain non-chromophoric polar amines, long chain nonchromophic anionic surfactant as well as oligomers of non-chromophoric non-ionic surfactants, respectively. The fritless columns showed good intra-day repeatibility and inter-day reproducibility of retention times, chiral and achiral resolutions and peak areas. Very satisfactory column-to-column and operator-to-operator reproducibility was demonstrated. PMID:22035695

Bragg, William; Shamsi, Shahab A.

2011-01-01

73

Azeotropic distillation in a middle vessel batch column. 1: Model formulation and linear separation boundaries  

Microsoft Academic Search

A mathematical model for the middle vessel batch distillation column (MVC) is developed using the concept of warped time analysis and used to study the qualitative dynamics of the MVC when it is used to separate multicomponent azeotropic mixtures. A limiting analysis is then developed for a MVC with an infinite number of trays, operated under infinite reflux\\/reboil ratios, under

Weiyang Cheong; Paul I. Barton

1999-01-01

74

Development of gamma-ray scanning facilities for on-line investigation of distillation columns.  

National Technical Information Service (NTIS)

Gamma-ray scanning facilities for on-line investigation of distillation columns which is based on the attenuation of gamma radiation was developed at the Unit Tenaga Nuklear. The system utilised Co-60 or Cs-137 as a gamma-ray emitter and NaI(Tl) detector ...

Mohd Azmi bin Ismail Jaafar bin Abdullah Jamaludin bin Omar

1994-01-01

75

Modified method to improve the design of Petlyuk distillation columns  

PubMed Central

Background A response surface analysis was performed to study the effect of the composition and feeding thermal conditions of ternary mixtures on the number of theoretical stages and the energy consumption of Petlyuk columns. A modification of the pre-design algorithm was necessary for this purpose. Results The modified algorithm provided feasible results in 100% of the studied cases, compared with only 8.89% for the current algorithm. The proposed algorithm allowed us to attain the desired separations, despite the type of mixture and the operating conditions in the feed stream, something that was not possible with the traditional pre-design method. The results showed that the type of mixture had great influence on the number of stages and on energy consumption. A higher number of stages and a lower consumption of energy were attained with mixtures rich in the light component, while higher energy consumption occurred when the mixture was rich in the heavy component. Conclusions The proposed strategy expands the search of an optimal design of Petlyuk columns within a feasible region, which allow us to find a feasible design that meets output specifications and low thermal loads. PMID:25061476

2014-01-01

76

Improving dual composition control in continuous distillation by a novel column design  

SciTech Connect

How a novel design of continuous distillation columns may impact the performance of conventional controllers when it is required to accurately control the purity of both products in a binary separation is analyzed. The proposed column layout is characterized by the presence of a middle vessel, to which two streams are fed: the liquid flow coming from the rectifying section and the feed to be separated. The actual liquid flow to the column is determined by the middle-vessel level controller. For different control configurations and conventional proportional-integral control, it is shown that using a middle-vessel column provides a way to reduce the interaction between the composition loops, in such a way that the control performance of middle-vessel columns may be made remarkably superior to that of the conventional columns. The results obtained are supported by a theoretical analysis based on the frequency-dependent relative gain array tool.

Barolo, M.; Papini, C.A.

2000-01-01

77

Laboratory studies of the behavior of undissolved solids in both pulsed and packed column extraction systems  

SciTech Connect

A substantial fraction of the finely divided undissolved solid material found in nuclear fuel reprocessing dissolver-product solutions is hydrophobic and tends to ``seek`` any organic-aqueous interface existing within countercurrent liquid-liquid extraction systems. While passing through pulsed-type columns this material is swept out of the aqueous phase by the combined surface area of the tiny bubbles of dispersed phase. Because these bubbles have a net velocity towards the end of the column where the nominal interface is located, the solids are swept in that direction too. These solids tend to gather in a three-phase ``crud`` layer at the nominal interface point. At equilibrium, about the same amount breaks off from the crud layer and escapes into the liquid exiting from that end of the column as enters it from the other side. If large enough, the crud layer can even interfere with interface detection and control equipment. In packed-column extraction systems, an additional problem is that feed solids can accumulate within the packing material to the point that the column `` floods`` or even totally plugs. The keys to preventing solids-related problems is the correct choice of interface level, and with packed columns, the addition of a ``pulsing leg`` at the bottom of the column. Pulsing packed column systems not only prevents solids from settling onto packing material but it also increses the number of theoretical stages available for extraction. 3 figs., 2 tabs.

Siemer, D.D.

1989-04-18

78

Characteristics of energy savings in an ideal heat-integrated distillation column (HIDiC)  

SciTech Connect

Distillation columns are major energy consumers in the chemical and petrochemical industries. In order to reduce energy consumption, considerable studies have been carried out and many distillation columns have been proposed. A Heat-Integrated Distillation Column (HIDiC) is constructed in such a manner that its rectifying and stripping sections are separated, while connected through a compressor and a throttling valve. Separation is benefited by heat integration between the two sections. To provide the driving forces for heat transfers from the rectifying to the stripping sections, the former must be operated at higher pressure than the latter. The HIDiC is expected to be more energy efficient than conventional columns, while at the expenses of some energy to raise up the pressure of the rectifying section. In this paper, it is shown by thermodynamical consideration that the HIDiC has high potential of exergy loss reduction compared with conventional columns. The effects of pressure difference on energy saving are analyzed, and possibility of energy saving is found in some case studies.

Nakaiwa, Masaru; Huang, Kejin; Owa, Masaru; Akiya, Takaji; Nakane, Takashi; Sato, Masahito [National Inst. of Materials and Chemical Research, Tsukuba (Japan). Dept. of Chemical Systems; Takamatsu, Takeichiro [Kyoto Univ. (Japan)

1997-12-31

79

Quantitative analysis of specific target DNA oligomers using a DNA-immobilized packed-column system  

Microsoft Academic Search

Although a DNA-immobilized packed-column (DNA-packed column), which relies on sequence-dependent interactions of target DNA\\u000a or mRNA (in the mobile phase) with DNA probes (on the silica particle) in a continuous flow process, could be considered as\\u000a an alternative platform for quantitative analysis of specific DNA to DNA chip methodology, the performance in practice has\\u000a not been satisfactory. In this study,

Seung Pil Pack; Tae-Hwe Heo; Kamakshaiah Charyulu Devarayapalli; Keisuke Makino

80

Design and Operation of Cryogenic Distillation Research Column for Ultra-Low Background Experiments  

NASA Astrophysics Data System (ADS)

Motivated by isotopically enriched germanium (76Ge and 73Ge) for monocrystalline crystal growth for neutrinoless double-beta decay and dark matter experiments, a cryogenic distillation research column was developed. Without market availability of distillation columns in the temperature range of interest with capabilities necessary for our purposes, we designed, fabricated, tested, refined and operated a two-meter research column for purifying and separating gases in the temperature range from 100-200K. Due to interest in defining stratification, purity and throughput optimization, capillary lines were integrated at four equidistant points along the length of the column such that real-time residual gas analysis could guide the investigation. Interior gas column temperatures were monitored and controlled within 0.1oK accuracy at the top and bottom. Pressures were monitored at the top of the column to four significant figures. Subsequent impurities were measured at partial pressures below 2E-8torr. We report the performance of the column in this paper.

Chiller, Christopher; Alanson Chiller, Angela; Jasinski, Benjamin; Snyder, Nathan; Mei, Dongming

2013-04-01

81

Industrial application of an extended fully thermally coupled distillation column to BTX separation in a naphtha reforming plant  

Microsoft Academic Search

Aromatic compounds are yielded from naphtha reforming in a petrochemical plant, and the products are separated with binary\\u000a distillation columns for benzene, toluene, xylene and heavy components in sequence. In this study, the first three columns\\u000a of the fractionation process in the naphtha reforming unit are replaced with an extended fully thermally coupled distillation\\u000a column (EFTCDC) also known as the

Young Han Kim; Dae Woong Choi; Kyu-Suk Hwang

2003-01-01

82

High Performance Liquid Chromatography Separations Using Columns Packed with Spherical ODS Particles. III. Effect of Column Dimensions on the Resolution of a Complex Mixture  

Microsoft Academic Search

Separations on short columns, (3 and 5 cm, packed with 3 ? ODS spherical materials) and somewhat larger ones (10 cm and 20 cm columns having 2.1 mm and 4.6 mm diameters packed with 5 ? ODS spherical materials) were compared using Aroclor 1254. With simple mixtures, the results showed that short columns can give separations comparable with those on

Haleem J. Issaq

1984-01-01

83

Effect of the packing pressure on the performance of C 18 reversed-phase liquid chromatographic columns  

Microsoft Academic Search

Early evidence has shown that HPLC columns packed with a given ODS phase give different performance, related to differences in their packing densities and external porosities. This effect was systematically studied on two groups of ten analytical (10×0.46 cm) columns packed with Kromasil and Zorbax 10 ?m spherical C18, respectively, using chloroform as the slurry solvent and methanol as the

Hong Guan-Sajonza; Georges Guiochona

1996-01-01

84

Structural design of fully thermally coupled distillation columns using a semi-rigorous model  

Microsoft Academic Search

A new structural design procedure for fully thermally coupled distillation columns (FTCDC) utilizing semi-rigorous material balances is proposed and applied to the design of example systems of butanol, BTX and hexane–heptane mixtures. The structural design can be directly incorporated in the design of commercial design software, giving basic information which is required at the beginning of simulation.The performance of the

Young Han Kim

2005-01-01

85

Azeotropic distillation in a middle vessel batch column. 1: Model formulation and linear separation boundaries  

SciTech Connect

A mathematical model for the middle vessel batch distillation column (MVC) is developed using the concept of warped time analysis and used to study the qualitative dynamics of the MVC when it is used to separate multicomponent azeotropic mixtures. A limiting analysis is then developed for a MVC with an infinite number of trays, operated under infinite reflux/reboil ratios, under the assumption of linear separation boundaries. It is determined that, under limiting conditions, the distillate product drawn from the MVC is given by the {alpha} limit set of the MVC still pot composition, while the bottoms product drawn from the MVC is given by the {omega} limit set of the MVC still pot composition. The net product composition is determined by taking a convex combination of the two products. The notions of steering the still pot composition, the vector cone of possible motion for the still pot composition, and the equivalency of the MVC to the combined operation of a batch rectifier and a stripper are also explored. The definition of batch distillation regions for the MVC operated at a given value of the middle vessel parameter {lambda}, and the bifurcation of these regions with the variation of {lambda}, are investigated. Lastly, a mathematical model incorporating the concept of warped time is developed for a multivessel column. The MVC can be viewed as a specific case of the multivessel column.

Cheong, W.; Barton, P.I. [Massachusetts Inst. of Tech., Cambridge, MA (United States)] [Massachusetts Inst. of Tech., Cambridge, MA (United States)

1999-04-01

86

Mobility of spiromesifen in packed soil columns under laboratory conditions.  

PubMed

On percolating water equivalent to 1,156 mm of rainfall, spiromesifen formulation did not leach out of 25-cm long columns, and 62.7 % of this was recovered in 5-10-cm soil depth. In columns treated with the analytical grade, 52.40 % of the recovered spiromesifen was confined to 0-5-cm soil depth, with 0.04 % in leachate fraction, suggesting high adsorption in soil. Results revealed that percolating 400 mL of water, residues of enol metabolite of spiromesifen was detected up to 20-25-cm soil layer, with 23.50 % residues of spiromesifen in this layer and 1.73 % in the leachate fraction indicating that metabolite is more mobile as compared to the parent compound. Results suggested a significant reduction in leaching losses of enol metabolite in amended soil columns with 5 % nano clay, farmyard manure (FYM), and vermicompost. No enol spiromesifen was recovered in the leachate in columns amended with nano clay, vermicompost, and FYM; however, 85.30, 70.5, and 65.40 %, respectively, was recovered from 0-5 cm-soil depth of column after percolating water equivalent to 1,156 mm of rainfall. Spiromesifen formulation is less mobile in sandy loam soil than analytical grade spiromesifen. The metabolite, enol spiromesifen, is relatively more mobile than the parent compound and may leach into groundwater. The study suggested that amendments were very effective in reducing the downward mobility of enol metabolite in soil column. Further, it resulted in greater retention of enol metabolite in the amendment application zone. PMID:25060860

Mate, Ch Jamkhokai; Mukherjee, Irani; Das, Shaon Kumar

2014-11-01

87

Development of chromatofocusing techniques employing mixed-mode column packings for protein separations.  

PubMed

Recent studies reported in the literature using mixed-mode chromatography (MMC) column packings have shown that multiple modes of interactions between the column packing and proteins can be usefully exploited to yield excellent resolution as well as salt-tolerant adsorption of the target protein. In this study, a mixed-mode separation method using commercially available column packings was explored which combines the techniques of hydrophobic-interaction chromatography and chromatofocusing. Two different column packings, one based on mercapto-ethyl-pyridine (MEP) and the other based on hexylamine (HEA) were investigated with regard to their ability to separate proteins when using internally generated, retained pH gradients. The effects of added salt and urea on the behavior of the retained pH gradient and the protein separation achieved when using MMC column packings for chromatofocusing were also investigated. Numerical simulations using methods developed in previous work were shown to agree with experimental results when using reasonable physical parameters. These numerical simulations were also shown to be a useful qualitative method to select the compositions of the starting and elution buffers in order to achieve desired shapes for the pH and ionic strength gradients. The use of the method to fractionate blood serum was explored as a prototype example application. PMID:24296295

Guo, Hui; Li, Xiang; Frey, Douglas D

2014-01-01

88

Kinetic performance evaluation and perspectives of contemporary packed column capillary electrochromatography.  

PubMed

Capillary electrochromatography (CEC) is in essence a highly efficient and fast separation technique but practical constraints limit the current performance, robustness and routine implementation of the technique. In this work the kinetic performance limit (KPL) curve was used to evaluate commercial packed column CEC; this firstly in order to assess the broader applicability of the kinetic plot approach in electrodriven chromatographic techniques, and secondly to allow a more general unbiased comparison with HPLC performance. Evaluations were performed with a mixture of well retained and electrophoretically neutral phenones, to allow the observation of only chromatographic processes. Initial CEC retention time irreproducibility issues were solved by applying high acetonitrile content (80%) in the mobile phase, and solute retention was increased by increasing the phenone chain length. Comparison was performed with HPLC, with a column packed with an identical stationary phase to allow measurement of the performance under optimal conditions, and not with ?-LC on the CEC column as extra column peak broadening phenomena would thereby negatively affect the ?-LC performance. This comparison demonstrated that current HPLC performance largely outcompetes what is achievable with contemporary packed column CEC. Interestingly, significantly improved CEC performance could be obtained at lower temperatures (10°C) indicating a persistent degree of joule heating phenomena taking place in the contemporary packed column (100?m) CEC approach. Effective suppression of the latter opens possibilities for increasing the applicable voltage and outperforming HPLC and UHPLC. PMID:24958031

De Smet, Seppe; Lynen, Frederic

2014-08-15

89

Azeotropic distillation in a middle vessel batch column. 2: Nonlinear separation boundaries  

SciTech Connect

On the basis of the analytical tools developed for the middle vessel column (MVC) operated under limiting conditions, analysis of the qualitative dynamics of the MVC in separating an azeotropic mixture is extended to the more realistic case in which the separation boundaries are nonlinear. The differences between batch stripper pot composition boundaries and batch rectifier pot composition being able to cross these pot composition boundaries. On the basis of these insights, operating procedures are developed in which ternary azeotropic mixtures of acetone, benzene, and chloroform can be separated into their constituent pure components, a separation not achievable with either the batch stripper or the batch rectifier. The operating procedures suggested for separating the ternary azeotropic mixture of acetone, benzene, and chloroform in the MVC are then shown to be the time analogues of sequences of continuous distillation columns that achieve the same separation. On the basis of this space-time analogy, further analogies are developed between the MVC and a continuous column, and it is postulated that many complex separations currently achieved with sequences of continuous columns can also be achieved with a single MVC. Thus, the MVC represents the ultimate multipurpose solvent recovery technology, as it can handle, in a batch multipurpose mode. separations that will otherwise require a dedicated continuous distillation sequence. Finally, the characteristics of perfect MVC batch entrainers, which allow the complete separation of any azeotrope into its constituent pure components in a single MVC, are discussed.

Cheong, W.; Barton, P.I. [Massachusetts Inst. of Tech., Cambridge, MA (United States)] [Massachusetts Inst. of Tech., Cambridge, MA (United States)

1999-04-01

90

Adsorption in columns packed with porous adsorbent particles having partially fractal structures.  

PubMed

A mathematical model is constructed and solved that could describe the dynamic behavior of the adsorption of a solute of interest in single and stratified columns packed with partially fractal porous adsorbent particles. The results show that a stratified column bed whose length is the same as that of a single column bed, provides larger breakthrough times and a higher dynamic utilization of the adsorptive capacity of the particles than those obtained from the single column bed, and the superior performance of the stratified bed becomes especially more important when the superficial velocity of the flowing fluid stream in the column is increased to accommodate increases in the system throughput. This occurs because the stratified column bed provides larger average external and intraparticle mass transfer and adsorption rates per unit length of packed column. It is also shown that increases in the total number of recursions of the fractal and the ratio of the radii between larger and smaller microspheres that make up the partially fractal particles, increase the intraparticle mass transfer and adsorption rates and lead to larger breakthrough times and dynamic utilization of the adsorptive capacity of the particles. The results of this work indicate that highly efficient adsorption separations could be realized through the use of a stratified column comprised from a practically reasonable number of sections packed with partially fractal porous adsorbent particles having reasonably large (i) total number of recursions of the fractal and (ii) ratio of the radii between larger and smaller microspheres from which the partially fractal particles are made from. It is important to mention here that the physical concepts and modeling approaches presented in this work could be, after a few modifications of the model, applied in studying the dynamic behavior of chemical catalysis and biocatalysis in reactor beds packed with partially fractal porous catalyst particles. PMID:23936911

Li, Min; Liapis, Athanasios I

2013-06-01

91

Simple capillary flow porometer for characterization of capillary columns containing packed and monolithic beds  

Microsoft Academic Search

A simple capillary flow porometer (CFP) was assembled for through-pore structure characterization of monolithic capillary liquid chromatography columns in their original chromatographic forms. Determination of differential pressures and flow rates through dry and wet short capillary segments provided necessary information to determine the mean diameters and size distributions of the through-pores. The mean through-pore diameters of three capillary columns packed

Yan Fang; H. Dennis Tolley; Milton L. Lee

2010-01-01

92

Packed-column hydrodynamic chromatography using 1-?m non-porous silica particles  

Microsoft Academic Search

150×3 mm I.D. columns, packed with 1-?m non-porous spherical silica particles, were used to separate soluble synthetic polymers by hydrodynamic chromatography. The columns exhibited a plate height of about 1.4 ?m allowing very fast and efficient separations of polymers in the molecular mass range 103?2·106 g\\/mol. The migration behaviour of polymers could be well described by a simple theoretical model.

E. Venema; J. C. Kraak; H. Poppe; R. Tijssen

1996-01-01

93

Methodological analysis of gamma tomography system for large random packed columns  

Microsoft Academic Search

Gamma ray tomography experiments have been carried out to detect spatial patterns in the porosity in a 0.27m diameter column packed with steel Rashig rings of different sizes: 12.6, 37.9, and 76mm. using a first generation CT system (Chen et al., 1998). A fast Fourier transform tomographic reconstruction algorithm has been used to calculate the spatial variation over the column

Pablo A. S. Vasquez; Carlos H. De Mesquita; Galo A. C. LeRoux; Margarida M. Hamada

2010-01-01

94

Investigation of numerical solution approaches to multicomponent batch distillation in packed beds  

SciTech Connect

Finite difference and orthogonal collocation techniques are used to obtain numerical solution of the differential contactor model that represents a packed column. In the orthogonal collocation approach, polynomial approximation to the model equations results in a sparse system of equations that is much smaller in dimension than with the other methods. Exploiting this sparsity and choosing the proper order for approximating polynomial are the critical issues. Higher CPU time associated with higher order of the polynomial necessitates use of finite elements in the collocation techniques. The authors study the accuracy and efficiency issues underlying all these approaches with the help of hydrocarbon mixture and ethanol esterification examples. The later case study is considered with both with and without the presence of reaction.

Wajge, R.M.; Wilson, J.M.; Pekny, J.F.; Reklaitis, G.V. [Purdue Univ., Lafayette, IN (United States). School of Chemical Engineering] [Purdue Univ., Lafayette, IN (United States). School of Chemical Engineering

1997-05-01

95

A LIQUID FILM MODEL OF TETRAKAIDECAHEDRAL PACKING TO ACCOUNT FOR THE ESTABLISHMENT OF EPIDERMAL CELL COLUMNS  

Microsoft Academic Search

The possibility that the organization of cells into columns in the mammalian epidermis may be a result of the close packing of these cells has been investigated in a model system involving the association of randomly produced soap bubbles into a stable truth. Upon floating to the surface of a liquid, soap bubbles have been found to spontaneously assemble into

David N. Menton

1976-01-01

96

Leaching, mobility and persistence of tebufenozide in columns packed with forest litter and soil  

Microsoft Academic Search

Leaching, downward mobility and persistence of tebufenozide was investigated under laboratory conditions in columns packed with forest litter and soil, after fortification with the analytical grade material (purity > 99.6%) and with two commercial formulations, RH?5992 2F (aqueous flowable) and RH?5992 ES (emulsion suspension). Two types of litter and soil were used: one type with relatively high amounts of sand

K. M. S. Sundaram

1996-01-01

97

On the use of intermediate reboilers in the rectifying section and condensers in the stripping section of a distillation column  

SciTech Connect

Advantages of an intermediate reboiler in the stripping section of a distillation column and an intermediate condenser in the rectifying section are well-known. For highly nonideal mixtures the distillation process can be improved by placing an intermediate reboiler in the rectifying section of the column or an intermediate condenser in the stripping section, which is counterintuitive. In consequence the more expensive heating utility used in the bottom reboiler can be partially replaced with a less expensive heating medium (at a lower temperature) used in the intermediate reboiler. Similarly, a portion of the condensing duty from the top condenser can be replaced with the less expensive condensing duty (at a higher temperature) in the intermediate condenser. This placement of reboilers (condensers) can be used to reduce the total number of stages in the distillation column with a lower (higher) level of utility. Operating and capital costs of the distillation process with an intermediate heat exchanger can be lower than those for a classic column. A simple method providing valuable insights on the possible placement of intermediate heat exchangers along the column is proposed. It is based on calculations of the vapor flow along the height of a reversible, binary distillation column performing the equivalent separation task.

Agrawal, R.; Fidkowski, Z.T. [Air Products and Chemicals Inc., Allentown, PA (United States)] [Air Products and Chemicals Inc., Allentown, PA (United States)

1996-08-01

98

Optimization of the thermal environment of columns packed with very fine particles.  

PubMed

The apparent reduced HETP (height equivalent to a theoretical plate) of columns packed with very fine 1.7mum BEH-C(18)particles were measured under isocratic conditions, for different thermal conditions applied to the surface wall (column left in still-air at laboratory temperature, column placed in the oven of the Acquity UPLC chromatograph heated at different temperatures, or column immersed in a water stream at different controlled temperatures). The sample was the low-molecular weight, highly diffusive compound naphtho[2,3-a]pyrene. The mobile phase was either pure acetonitrile or a mixture of acetonitrile and water (85/15, v/v). The plot of the measured HETPs versus the mobile phase flow velocity begins to deviate from the classical isothermal van Deemter curve or the advantages of using very fine particles begins to disappear when the heat power released by the friction of the stream percolating through the packed bed exceeds 4W per unit length of column (m). These effects are minimum when (1) the temperature of the column wall is not controlled and the wall remains in contact with air; or (2) a suitable difference between the temperature of the column wall (hot) and the temperature of the entering liquid (cooler) is set by the analyst. PMID:19150538

Gritti, Fabrice; Guiochon, Georges

2009-02-27

99

Effects of kinematic viscosity of the slurry on the packing efficiency of PEEK microbore columns for liquid chromatography  

Microsoft Academic Search

Summary  The kinematic viscosity of the slurry used for the packing of microbore columns for liquid chromatography has been correlated\\u000a with the packing efficiency. The columns were packed into polyetheretherketone (PEEK) tubing with an internal diameter of\\u000a 0.5 mm using unbonded and bonded spherical silica gels under constant pressure conditions. Higher efficiencies were obtained\\u000a using slurries suspended in aqueous solutions of

T. M. Zimina; Roger M. Smith; P. Myers; B. W. King

1995-01-01

100

A liquid film model of tetrakaidecahedral packing to account for the establishment of epidermal cell columns.  

PubMed

The possiblity that the organization of cells into columns in the mammalian epidermis may be a result of the close packing of these cells has been investigated in a model system involving the association of randomly produced soap bubbles into a stable froth. Upon floating to the surface of a liquid, soap bubbles have been found to spontaneously assemble into precise columns of interdigitating bubbles. The tetrakaidecahedral shape and the spatial configuration of these bubbles closely resemble those of stacked epidermal cells, although the columns of a froth were oriented at a 60degrees angle to their substratum rather than at right angles as occurs in the epidermal cell columns. These observations lend support to the theory that the organization of the cells in the epidermis into columns is due to the assumption of the keratocytes of a minimum surface-close packing array. Such an organizing mechanism would be independent of both positional control of the underlying mitoses and active guidance of the cells as they become superficially displaced within the epidermis. The observation that a high rate of cell turnover is incompatible with the epidermal column structure may be related to the finding that rapidly produced soap bubbles do not, at least initially, assemble into a columnar array. PMID:1270835

Menton, D N

1976-05-01

101

Final Report - Advanced Hydraulic and Mass Transfer Models for Distillation Column Optimization and Design  

SciTech Connect

The project successfully developed a computational fluid dynamics (CFD) based simulation of the hydrodynamics of flow in a commercial structured packing element. This result fulfilled the prime objective of the research program. The simulation utilized commercial CFD code marketed by Fluent Inc. in combination with a novel graphical interface developed by Oak Ridge National Lab. The end product will allow the design of next generation column internals without the need for extensive experimental validation and will expand the fundamental understanding of the vapor-liquid contacting process.

Eldridge, Robert, B.

2005-10-13

102

?iocolloid and colloid transport through water-saturated columns packed with glass beads: Effect of gravity  

NASA Astrophysics Data System (ADS)

The role of gravitational force on biocolloid and colloid transport in water-saturated columns packed with glass beads was investigated. Transport experiments were performed with biocolloids (bacteriophages: ??174, MS2) and colloids (clays: kaolinite KGa-1b, montmorillonite STx-1b). The packed columns were placed in various orientations (horizontal, vertical, and diagonal) and a steady flow rate of Q=1.5 mL/min was applied in both up-flow and down-flow modes. All experiments were conducted under electrostatically unfavorable conditions. The experimental data were fitted with a newly developed, analytical, one dimensional, colloid transport model, accounting for gravity effects. The results revealed that flow direction has a significant influence on particle deposition. The rate of particle deposition was shown to be greater for up-flow than for down-flow direction, suggesting that gravity was a significant driving force for biocolloid and colloid deposition. Schematic illustration of a packed column with up-flow velocity having orientation (-i) with respect to gravity. The gravity vector components are: g(i)= g(-z) sin? i, and g(-j)= -g(-z) cos? j. Experimental setup showing the various column arrangements: (a) horizontal, (b) diagonal, and (c) vertical.

Chrysikopoulos, C. V.; Syngouna, V. I.

2013-12-01

103

Azeotropic distillation in a middle vessel batch column. 3: Model validation  

SciTech Connect

A dimensional time model of the middle vessel batch distillation column (MVC) is developed in the ABACUSS process modeling environment, and simulations are conducted to validate the theoretical insights developed for the operation of the MVC based on a warped time model of the MVC. The qualitative dynamics of the MVC operated in the presence of linear separation boundaries are validated via simulations conducted on the ternary azeotropic mixture of acetone, chloroform, and methanol. It is also shown via simulation that the separation results obtained from a column with significant but reasonable amounts of holdup on the trays are not significantly different from a column in which holdup in the trays is assumed to be negligible. Theoretical operating policies for separating the azeotrope of acetone and chloroform using benzene as a batch entrainer are also validated using the ABACUSS model. Finally, the authors explore the advantages and disadvantages of different feasible operating policies for separating a mixture of acetone, benzene, and chloroform completely into its constituent pure components.

Cheong, W.; Barton, P.I. [Massachusetts Inst. of Tech., Cambridge, MA (United States)] [Massachusetts Inst. of Tech., Cambridge, MA (United States)

1999-04-01

104

Chromate transport through columns packed with surfactant-modified zeolite/zero valent iron pellets.  

PubMed

Chromate transport through columns packed with zeolite/zero valent iron (Z/ZVI) pellets, either untreated or treated with the cationic surfactant hexadecyltrimethylammonium (HDTMA), was studied at different flow rates. In the presence of sorbed HDTMA, the chromate retardation factor increased by a factor of five and the pseudo first-order rate constant for chromate reduction increased by 1.5-5 times. The increase in rate constant from the column studies was comparable to a six-fold increase in the rate constant determined in a batch study. At a fast flow rate, the apparent delay in chromate breakthrough from the HDTMA modified Z/ZVI columns was primarily caused by the increase in chromate reduction rate constant. In contrast, at a slower flow rate, the retardation in chromate transport from the HDTMA modified Z/ZVI columns mainly originated from chromate sorption onto the HDTMA modified Z/ZVI pellets. Due to dual porosity, the presence of immobile water was responsible for the earlier breakthrough of chromate in columns packed with zeolite and Z/ZVI pellets. The results from this study further confirm the role of HDTMA in enhancing sorption and reduction efficiency of contaminants in groundwater remediation. PMID:17448519

Li, Zhaohui; Kirk Jones, H; Zhang, Pengfei; Bowman, Robert S

2007-08-01

105

Effect of fouling on the capacity and breakthrough characteristics of a packed bed ion exchange chromatography column  

Microsoft Academic Search

This study examined the impact of fouling with yeast homogenate on capacity and breakthrough performance of an ion exchange packed bed column. Column performance was assessed by analysis of breakthrough curves obtained with BSA as a test protein. The overall impact of fouling on breakthrough performance depended heavily on the level of clarification of the feed stream. Challenging the column

Sun Chau Siu; Helen Baldascini; David C. Hearle; Mike Hoare; Nigel J. Titchener-Hooker

2006-01-01

106

Distillation: Energy Savings and Other Benefits From the Use of High Efficiency Packings  

E-print Network

of high-efficiency packings are available in the market today: structured packings and specialized random packings. Structured packings, shown in Figure 2, are commonly fabricated of corrugated metal sheets, with the corrugations providing... the geometry for the liquid and gas flow channel. Liquid flows down the walls of the corrugation in a film form, while the vapor moves upward in the triangular space. Very intense lateral mixing is provided by this geometry as the gas and liquid flows...

Bravo, J. L.; Fair, J. R.; Humphrey, J. L.

107

Process development of continuous hydrogen production by Enterobacter aerogenes in a packed column reactor  

Microsoft Academic Search

Hydrogen bioproduction from agro-industrial residues by Enterobacter aerogenes in a continuous packed column has been investigated and a complete reactor characterization is presented. Experimental runs carried out at different residence time, liable of interest for industrial application, showed hydrogen yields ranging from 1.36 to 3.02 mmolH2mmolуglucose or, in other words, from 37.5% to 75% of the theoretical hydrogen yield. A

E. Palazzi; B. Fabiano; P. Perego

2000-01-01

108

Comparison between the loading capacities of columns packed with partially and totally porous fine particles  

Microsoft Academic Search

The adsorption isotherms of phenol, caffeine, insulin, and lysozyme were measured on two C18-bonded silica columns. The first one was packed with classical totally porous particles (3?m Luna(2)-C18from Phenomenex, Torrance, CA, USA), the second one with shell particles (2.7?m Halo-C18 from Advanced Materials Technology, Wilmington, DE, USA). The measurements were made at room temperature (T=295±1K), using mainly frontal analysis (FA)

Fabrice Gritti; Georges Guiochon

2007-01-01

109

Adsorption of Synthetic Water?Soluble Polymers from Thermodynamically Good Solvents onto Microporous Column Packings  

Microsoft Academic Search

The elution behavior of polyethylene glycols, polyethylene oxide, polypropylene glycols, and sodium poly(methacrylic acid) in several mobile phases (water, methanol, acetone, dimethylacetamide, diethylene glycol monobutyl ether) was studied. The elution behavior of polyvinyl alcohol in water was also measured. ZSM?5 and Y?type zeolites were used as column packings. Full retention of the polymers was found in several chromatographic systems. Polyethylene

Tibor Macko; Martina Adler; Harald Pasch; Joeri F. Denayer; Achim Raphael

2004-01-01

110

Ultrahigh-pressure reversed-phase liquid chromatography in packed capillary columns.  

PubMed

The use of extremely high pressures in liquid chromatography can improve the efficiency and reduce analysis time for columns packed with small particles. In this work, fused-silica capillaries with inner diameters of 30 microns are slurry packed with 1.5 microns nonporous octadecylsilane-modified silica particles. These columns are prepared in lengths up to 66 cm with packing pressures as high as 4100 bar (60,000 psi). Near the optimum flow rate, columns generate as many as 300,000 theoretical plates for lightly retained compounds (k' < 0.5) and over 200,000 plates for more retained compounds (k' approximately 2). These translate to plate heights (Hmin) as low as 2.1 microns. The pressures required to run at optimum flow rates are on the order of 1400 bar (20,000 psi). Analysis times at these pressures are on the order of 30 min (k' approximately 2) and can be reduced to less than 10 min at higher than optimum flow rates. Capacity factors are observed to increase linearly with applied pressure. PMID:9075400

MacNair, J E; Lewis, K C; Jorgenson, J W

1997-03-15

111

Cotransport of Pseudomonas putida and kaolinite particles through water-saturated columns packed with glass beads  

NASA Astrophysics Data System (ADS)

This study is focused on Pseudomonas putida bacteria transport in porous media in the presence of suspended kaolinite clay particles. Experiments were performed with bacteria and kaolinite particles separately to determine their individual transport characteristics in water-saturated columns packed with glass beads. The results indicated that the mass recovery of bacteria and clay particles decreased as the pore water velocity decreased. Batch experiments were carried out to investigate the attachment of Pseudomonas putida onto kaolinite particles. The attachment process was adequately described by a Langmuir isotherm. Finally, bacteria and kaolinite particles were injected simultaneously into a packed column in order to investigate their cotransport behavior. The experimental data suggested that the presence of clay particles significantly inhibited the transport of bacteria in water-saturated porous media. The observed reduction of Pseudomonas putida recovery in the column outflow was attributed to bacteria attachment onto kaolinite particles, which were retained onto the solid matrix of the column. A mathematical model was developed to describe the transport of bacteria in the presence of suspended clay particles in one-dimensional water-saturated porous media. Model simulations were in good agreement with the experimental results.

Vasiliadou, Ioanna A.; Chrysikopoulos, Constantinos V.

2011-02-01

112

Methodological analysis of gamma tomography system for large random packed columns.  

PubMed

Gamma ray tomography experiments have been carried out to detect spatial patterns in the porosity in a 0.27 m diameter column packed with steel Rashig rings of different sizes: 12.6, 37.9, and 76 mm. using a first generation CT system (Chen et al., 1998). A fast Fourier transform tomographic reconstruction algorithm has been used to calculate the spatial variation over the column cross section. Cross-sectional gas porosity and solid holdup distribution were determinate. The values of cross-sectional average gas porosity were epsilon=0.849, 0.938 and 0.966 for the 12.6, 37.9, and 76 mm rings, respectively. Radial holdup variation within the packed bed has been determined. The variation of the circumferentially averaged gas holdup in the radial direction indicates that the porosity in the column wall region is a somewhat higher than that in the bulk region, due to the effect of the column wall. PMID:20031428

Vasquez, Pablo A S; De Mesquita, Carlos H; LeRoux, Galo A C; Hamada, Margarida M

2010-01-01

113

Column performance of granular activated carbon packed bed for Pb(II) removal.  

PubMed

The excessive release of lead from lead acid batteries, smelting plant into the environment is a major concern worldwide. Adsorption process is among the most effective techniques for lead removal from wastewater and activated carbon has been widely used as an adsorbent. In this paper an attempt has been made to investigate the adsorption behaviour of Pb(II) from aqueous systems onto granular activated carbon using the batch mode and continuous mode in a packed bed column with more successive service and regeneration. The experiments were performed at constant temperature and dimensions of column and packed bed of granular activated carbon with variation of flows through the bed and concentrations of lead solutions. Breakthrough points were found out for the adsorption of lead on the adsorbent using continuous-flow column operation by varying different operating parameters like hydraulic loading rate from 4 to 16 m(3)/h m(2) and feed concentrates from 20 to 60 mg/l. Granular activated carbon column regeneration using 0.5 M concentration of HNO(3) has been investigated. Results indicate encouraging performance towards removal of Pb(II). PMID:18249492

Dwivedi, Chandra P; Sahu, J N; Mohanty, C R; Mohan, B Raj; Meikap, B C

2008-08-15

114

Control of packed column fouling in the continuous fermentation and stripping of ethanol.  

PubMed

By recycling the contents of a 14 L fermentor through a stripping column to continuously remove ethanol and reduce product inhibition, continuous complete conversion of nutrient feed containing 600 g/L glucose was achieved in a small pilot plant. Ethanol was recovered from the carbon dioxide stripping gas in a refrigerated condenser, and the gas was reheated with steam and recycled by a blower. Productivity of ethanol in the fermentor as high as 15.8 g/L/h and condensate production of up to 10 L/day of almost 50% by volume ethanol were maintained for up to 60 days of continuous operation. Weekly washing of the column packing in situ was required to prevent loss of performance caused by attached growth of yeast cells, which restricts the gas flow rate through the stripping column. (c) 1996 John Wiley & Sons, Inc. PMID:18627085

Taylor, F; Kurantz, M J; Goldberg, N; Craig, J C

1996-07-01

115

Simulation of hydrogen sulphide absorption in alkaline solution using a packed column.  

PubMed

In this work, a simulation tool was developed for hydrogen sulphide (H2S) removal in an alkaline solution in packed columns working at countercurrent. Modelling takes into account the mass-transfer enhancement due to the reversible reactions between H2S and the alkaline species ([Formula: see text], [Formula: see text] and HO(-)) in the liquid film. Many parameters can be controlled by the user such as the gas and liquid inlet H2S concentrations, the gas and liquid flow rates, the scrubbing liquid pH, the desired H2S removal efficiency, the temperature, the alkalinity, etc. Since the influence of the hydrodynamic and mass-transfer performances in a packed column is well known, the numerical resolutions performed were dedicated to the study of the influence of the chemical conditions (through the pH and the alkalinity), the temperature and the liquid-to-gas mass flow rate ratio (L/G). A packed column of 3 m equipped with a given random packing material working at countercurrent and steady state has been modelled. The results show that the H2S removal efficiency increases with the L/G, the pH, the alkalinity and more surprisingly with the temperature. Alkalinity has a very significant effect on the removal efficiency through the mass-transfer enhancement and buffering effect, which limits pH decreasing due to H2S absorption. This numerical resolution provides a tool for designers and researchers involved in H2S treatment to understand deeper the process and optimize their processes. PMID:25244138

Azizi, Mohamed; Biard, Pierre-François; Couvert, Annabelle; Ben Amor, Mohamed

2014-12-01

116

PRECISION AND ACCURACY IN THE DETERMINATION OF ORGANICS IN WATER BY FUSED SILICA CAPILLARY COLUMN GAS CHROMOTOGRAPHY/MASS SPECTROMETRY AND PACKED COLUMN GAS CHROMATOGRAPHY/MASS SPECTROMETRY  

EPA Science Inventory

Two general methods for the identification and measurement of organic compounds in water are compared. One method employs packed column chromatography and the other fused silica capillary column chromatography. The two gas chromatography/mass spectrometry (GC/MS) methods use diff...

117

Nitrate removal from groundwater in columns packed with reed and rice stalks.  

PubMed

Nitrate leaching contaminates groundwater. The objective of this study was to determine if reed and rice stalks could enhance denitrification and reduce nitrate leaching into groundwater. Artificial groundwater spiked with nitrate and field groundwater samples were tested in the columns in sand reactors packed with either reed or rice stalks. The maximum nitrate removal rates were determined to be 1.93 and 1.97 mg nitrate-N l(-1) h(-1), respectively, in the reed and rice stalk-packed columns. The maximum nitrate-nitrogen removal rate in reactors packed with reed stalk was 1.33 mg nitrate-N l(-1) h(-1) when experimented with natural groundwater. Chemical oxygen demand consumption was higher when rice stalk (176.1 mg l(-1)) was used as the substrate, compared to reed stalk (35.2 mg l(-1)) at the same substrate dosage. No nitrite accumulation was detected during the test. The results demonstrate that agricultural byproducts, such as reed and rice stalks, may be used as substrate amendments for enhanced denitrification in natural settings, such as lakeside lagoons, ditches or wetlands. PMID:22329150

Qian, Jiazhong; Wang, Zhiping; Jin, Song; Liu, Yong; Chen, Tianhu; Fallgren, Paul H

2011-10-01

118

Surface association of motile bacteria and apparent tortuosity values in packed column experiments  

NASA Astrophysics Data System (ADS)

Mathematical models used previously to obtain transport parameters from experimental investigations of bacterial transport in packed columns by Olson et al. (2005) yielded apparent tortuosity values that were an order of magnitude higher than expected for packed beds. The association of motile bacteria with solid surfaces of porous media, due to their swimming, contributed to the large apparent tortuosity values evaluated from packed column experiments; a modification of the transport equations to account for surface association yielded tortuosity values that were physically more reasonable. Although it was not possible to uniquely determine values of the kinetic parameters for surface association because of limitations with the experimental methods used by Olson et al., it was possible to constrain the range of values. A theoretical derivation of the mean residence time for swimming bacteria at a surface provided qualitative and quantitative support for including surface association terms in the transport model. This analysis shows that surface association can be a significant factor in modeling bacterial migration, and consideration of bacterial swimming properties such as run lengths and turn angles is important for predicting bacterial transport in saturated granular media typical of groundwater environments.

Narayanaswamy, Karthik; Ford, Roseanne M.; Smith, James A.; Fernandez, Erik J.

2009-07-01

119

CO2 absorption in nanofluids in a randomly packed column equipped with magnetic field  

NASA Astrophysics Data System (ADS)

Magnetic nanofluids have been used for absorption of CO2 in a packed column in the presence of magnetic field. Adding nanoparticles into the solvent enhances mass transfer characteristics. The optimum concentrations of Fe3O4/water and NiO/water nanofluids are 0.005, and 0.01 % respectively, and the maximum enhancement of mass transfer rate in comparison with pure water is 12 and 9.5 % respectively. The magnetic field showed positive effect on the CO2 absorption performance.

Salimi, J.; Haghshenasfard, M.; Etemad, S. Gh.

2014-10-01

120

Transport of Viruses Through Saturated and Unsaturated Columns Packed With Sand  

NASA Astrophysics Data System (ADS)

Laboratory-scale virus transport experiments were conducted in columns packed with sand under saturated and unsaturated conditions. The viruses employed were the male-specific RNA coliphage, MS2, and the Salmonella typhimurium phage, PRD1. The mathematical model developed by Sim and Chrysikopoulos [2000] to quantify the processes responsible for removal of viruses during vertical transport in one-dimensional, unsaturated porous media was used to fit the data collected from the laboratory experiments. The liquid to liquid-solid and liquid to air-liquid interface mass transfer rate coefficients were shown to increase for both bacteriophage as saturation levels were reduced. The experimental results indicate that even for unfavorable attachment conditions within a sand column (e.g., phosphate-buffered saline solution; pH = 7.5; ionic strength = 2 mM), saturation levels can affect virus transport through porous media.

Anders, R.; Chrysikopoulos, C. V.

2008-05-01

121

Effects of reflux ratio and feed conditions for the purification of bioethanol in a continuous distillation column  

NASA Astrophysics Data System (ADS)

Continuous distillation column was used for the purification of bioethanol from fermentation of molasses using Saccharomyces cerevisia. Bioethanol produced was at 8.32% (v/v) level. The efficiency of continuous distillation process was evaluated based on reflux ratio, and feed condition. The lab results were validated using COFE simulation Software. The analyses showed that both reflux ratio and feed condition had significant effects on the distillation process. Stages increased from 1.79 to 2.26 as the reflux ratio was decreased from 90% to 45% and the saturated feed produced lower mole fraction of desired product. We concluded that the lower reflux ratio with cold feed condition was suitable for higher mole fraction of top product.

Dasan, Y. K.; Abdullah, M. A.; Bhat, A. H.

2014-10-01

122

Report on Qiagen Columns with Precipitation versus Packed Bed Technology for Trace Amounts of DNA  

SciTech Connect

The assured limit of detection (LOD), where 100% of the PCR assays are successful, for the Qiagen spin column is dramatically improved when combined with an ethanol precipitation step of the eluted sample. A detailed SOP for the ethanol precipitation was delivered as a separate report. A key finding in the precipitation work was to incubate the ethanol precipitation at -20{sup o}C overnight when concentrating low copy number samples. Combining this modified ethanol precipitation with the Qiagen spin columns, the limit of assured detection was improved by 1-2 orders of magnitude, for the aliquot and assay variables used. The lower limit of detection (defined as when at least 1 assay of 1 aliquot was positive) was only improved by approximately 1 order of magnitude. The packed bed process has the potential of a 20-fold improvement in the limit of detection compared to Qiagen plus precipitation, based on a mass balance analysis for the entire DNA concentration and purification processes. Figure ES1 shows a mass balance for all the DNA processing steps. The packed bed process minimizes losses from elution, precipitation, and pipetting (aliquoting and transferring). Figure ES1 assumes that 100 copies of DNA serve as the input sample. Efficiencies for each step have been estimated based on our experiences or a worst case scenario (for example, a 50% loss was assumed for pipetting). Table ES1 summarizes the number of copies that are the input template for PCR assuming 100 copies of DNA are processed through the three options detailed in Figure ES1.Theoretically a 20-fold increase in the number of starting copies in the PCR reaction is gained when the DNA is concentrated, purified and then amplified directly on the surface of the beads in the packed bed.

Wheeler, E K; Erler, A M; Seiler, A

2008-02-05

123

Design of a fully thermally coupled distillation column for hexane process using a semi-rigorous model  

Microsoft Academic Search

An industrial scale hexane process is designed for the implementation of a fully thermally coupled distillation column (FTCDC).\\u000a A semi-rigorous material balance and Peng-Robinson equilibrium relation are utilized in the structural design. The operational\\u000a design is conducted with a commercial design program, the HYSYS. The design outcome of the structural design indicates it\\u000a to be comparable with the practical system

Young Han Kim; Kyu Suk Hwang; Masaru Nakaiwa

2004-01-01

124

Direct coupling of packed column supercritical fluid chromatography to continuous corona discharge ion mobility spectrometry.  

PubMed

In this study, packed column supercritical fluid chromatography (SFC) was directly coupled to a continuous corona discharge (CD) ion mobility spectrometer (IMS) with several modifications. The main advantage of the developed detector is its capability to introduce full column effluent up to 2000 mL min(-1) CO(2) gas directly into the IMS cell relative to 40 mL min(-1) CO(2) gas as a maximum tolerance, reported for the previous IMS detectors. This achievement was made possible because of using corona discharge instead of (63)Ni as an ionization source and locating the inlet and outlet of the CO(2) gas in the counter electrode of the CD in opposite direction. In addition, a heated interface was placed between back pressure regulator (BPR) and the IMS cell to heat the output of the BPR for introducing sample as the gas phase into the IMS cell. Furthermore, a make-up methanol flow was introduced between the column outlet and BPR to provide a more uniform flow through the BPR and also to prevent freezing and deposition of the analytes in the BPR. The performance of the SFC-CD-IMS was evaluated by analysis of testosterone, medroxyprogesterone, caffeine, and theophylline as test compounds and figures of merit for these compounds have been calculated. PMID:23261285

Rahmanian, A; Ghaziaskar, H S; Khayamian, T

2013-01-11

125

Monitoring Anaerobic TCE Degradation by Evanite Cultre in Column Packed with TCE-Contaminated Soil  

NASA Astrophysics Data System (ADS)

Trichloroethylene (TCE) is a long-term common groundwater pollutant because the compound with high density is slowly released into groundwater. Physical and chemical remediation processes have been used to clean-up the contaminant, but novel remediation technology is required to overcome a low efficiency of the traditional treatment process. Many researchers focused on biological process using an anaerobic TCE degrading culture, dehalococcoides spp., but it still needs to evaluate whether the process can be applied into field scale under aerobic condition. Therefore, in this work we examined two different types (i.e., Natural attenuation and bioaugmentation) of biological remediation process in anaerobic column packed with TCE-contaminated soil. A TCE degradation by indigenous microorganisms was confirmed by monitoring TCE and the metabolites (c-DCE, VC, ETH). However, TCE was transformed and stoichiometry amount of c-DCE was produced, and VC and ETH was not detected. To test bioaugmentation of Evanite culture containing dehalococcoides spp., Evanite culture was injected into the column and TCE degradation to c-DCE, VC, ETH was monitored. We are evaluating the transport of the Evanite culture in the column by measuring TCE and VC reductases. In the result, the TCE was completely degraded to ETH using hydrogen as electron donor generate by hydrogen-production fermentation from formate.

Ko, J.; Han, K.; Ahn, G.; Park, S.; Kim, N.; Ahn, H.; Kim, Y.

2011-12-01

126

Stable isotope fractionations during reactive transport of phosphate in packed-bed sediment columns.  

PubMed

Characterizing reactivity and fate of contaminants in subsurface environments that are isolated from direct visualization is a major challenge. Stable isotopes coupled with concentration could be used as a potential tool to quantitatively analyze the chemical variability of the contaminant during reactive transport processes in the subsurface environment. This study was aimed at determining whether abiotic reactions of phosphate during its transport involve fractionation of oxygen isotopes in phosphate (?(18)Op). It included the effects of solution chemistry and hydrodynamics on ?(18)Op values during phosphate transport through a packed-bed column prepared by using natural sediment collected from the Cape Cod aquifer in Massachusetts. Results show that the isotopic fractionation between effluent and influent phosphate at early stage of transport could be ~1.3‰ at higher flow rates with isotopically-light phosphate (P(16)O4) preferentially retained in the sediment column. This fractionation, however, decreased and became insignificant as more phosphate passed through the column. Mobilization of phosphate initially sorbed onto sediments caused a large kinetic isotopic fractionation with isotopically-light phosphate preferentially remobilized from the sediment column, but over longer time periods, this fractionation decreased and became insignificant as well. These results collectively suggest that abiotic reactive transport processes exert minimal influence on the ?(18)Op composition of subsurface systems. Alternatively, fluctuation in flow rate and subsequent remobilization of phosphate could be detectable through transient changes in ?(18)Op values. These findings extend the burgeoning application of ?(18)Op to identify the different sources and geochemical processes of phosphate in the subsurface environments. PMID:24055952

Jaisi, Deb P

2013-11-01

127

Carbon dioxide–air mixtures: mass transfer in recycling packed-bed absorption columns operating under high liquid flow rates  

Microsoft Academic Search

The absorption of carbon dioxide–air mixtures in water in a packed-bed recirculating absorption column with an inner diameter of 0.08m and a length of 1.20m was investigated. A model is derived and numerically solved for recycling packed-bed absorption systems in order to determine the overall mass transfer coefficients. The relationship between the KLa values calculated in this work and the

Vural Evren; Tuncay Ça?atay; Ahmet R. Özdural

1999-01-01

128

Boron isotope fractionation in liquid chromatography with boron-specific resins as column packing material  

SciTech Connect

Boron-specific resins with n-methyl glucamine as the functional group were used as column packing material of liquid chromatography for boron isotope separation. The shapes of chromatograms in reverse breakthrough experiments were heavily dependent on the pH of the eluents, and there existed a pH value at which a chromatogram of the displacement type was realized nearly ideally. The value of the single-stage separation factor for the boron isotopes varied between 1.010 and 1.022, depending on the temperature and the form of the resins. The existence of the three-coordinate boron species in addition to the four-coordinate species in the resin phase is suggested.

Oi, Takao; Shimazaki, Hiromi; Ishii, Reiko [Sophia Univ., Tokyo (Japan); Hosoe, Morikazu [National Defense Academy, Kanagawa (Japan)

1997-07-01

129

Synthesis of porous polyaromatic column packings for GC analysis of extraterrestrial atmospheres  

NASA Technical Reports Server (NTRS)

The preparation of a polymer for the Pioneer-Venus Large Probe Gas Chromatograph and another polymer for gas-chromatographic analysis of the Jovian atmosphere is described. Technical-grade divinylbenzene is used as a reliable and economical source of monomer for the preparation of polymer beads. The discussion covers monomeric preparation, polymerization apparatus, first-stage polymer beads, second-stage polymer beads, amino-polymer, columns and gas-chromatographic testing instrumentation used. The polymer for the Pioneer-Venus gas chromatograph is also suitable for ammonia but not for amine analysis. However, the polymer for the analysis of the Jovian atmosphere is a chemically derivatized aromatic polymer that is suitable for amine analysis. The two-stage polymerization produces a highly efficient polymer packing clearly superior to others prepared by adjusted dilution of the aqueous-organic suspension system.

Woeller, F. H.; Pollock, G. E.

1978-01-01

130

Continuous phosphorus removal from water by physicochemical method using zero valent iron packed column.  

PubMed

Excessive phosphorus in aquatic systems causes algal bloom resulting in eutrophication. To treat wastewater including effluent of wastewater treatment plant containing various amounts of phosphorus, a series of continuous experiments on removal of phosphorus from water were performed by using an electrochemical method. The spherical type of zero valent iron (ZVI) and silica sand were packed at appropriate volume ratio of 1:2 in a cylindrical column. An electric potential was applied externally, which can be changed as per the operational requirement. The results indicate that optimum hydraulic retention time of 36 min was required to meet the effluent standards with our laboratory-scale experimental setup. Lower amounts of phosphorus were removed by precipitation due to contact with iron, and additional electric potential was not required. In order to remove high amounts of phosphorus (around 150 mg/L as phosphate), external electric potential of 600 V was applied to the reactor. As the precipitation of phosphate mainly occurs at neutral pH, it is likely that FeHPO4 will be the main phosphorus-containing compound. Through the results of the large-scale experiments, the ZVI packed reactor can be used as a filter for removal of phosphorus of less than 10 mg/L as phosphate concentration. PMID:25225938

Jeong, Joo-Young; Ahn, Byoung-Min; Kim, Yu-Jin; Park, Joo-Yang

2014-01-01

131

Use of a Packed-Column Bioreactor for Isolation of Diverse Protease-Producing Bacteria from Antarctic Soil  

Microsoft Academic Search

Seventy-five aerobic heterotrophs have been isolated from a packed-column bioreactor inoculated with soil from Antarctica. The column was maintained at 10°C and continuously fed with a casein-containing medium to enrich protease producers. Twenty-eight isolates were selected for further characterization on the basis of morphology and production of clearing zones on skim milk plates. Phenotypic tests indicated that the strains were

Nathalie Wery; Ursula Gerike; Ajay Sharman; Julian B. Chaudhuri; David W. Hough; Michael J. Danson

2003-01-01

132

Silver ion chromatography using solid-phase ex- traction columns packed with a bonded-sulfonic acid phase  

Microsoft Academic Search

Commercial solid-phase extraction columns packed with a stationary phase with bonded benzenesulfonic acid groups are readily converted to the silver ion form and can then be used for silver ion chromatography of lipids. To illustrate the utility of such procedures, methyl ester derivatives of fatty acids with zero to six double bonds were separated from each other by a simple

William W. Christie

133

Feasability of neat carbon dioxide packed column comprehensive two dimensional supercritical fluid chromatography.  

PubMed

The design and implementation of comprehensive two dimensional supercritical fluid chromatography (SFC) using neat carbon dioxide as the mobile phase is described. Two conventional supercritical fluid chromatographs were hyphenated via an on line comprehensive 2D liquid chromatography like interface; it consisted of a two loop switching valve allowing the collection of the first dimension column effluent, the second dimension separation of a fraction being performed during the time allowed for the collection of the subsequent fraction of the first dimension eluent. Both dimension separations were monitored via UV detection; for the second dimension, the main flow was diverted to implement flame ionisation detection for the detection of hydrocarbons and the construction of the corresponding colour plots. Some key parameters related to the interfacing of the two dimensions and the chromatographic conditions used in both dimensions are discussed. In this preliminary report, the feasibility of comprehensive 2D SFC is demonstrated on synthetic mixtures of hydrocarbons and its potential on real sample analysis is illustrated by the separation of coal derived vacuum distillate. PMID:22533910

Guibal, Pierre; Thiébaut, Didier; Sassiat, Patrick; Vial, Jérôme

2012-09-14

134

Comparison of general rate model with a new model—artificial neural network model in describing chromatographic kinetics of solanesol adsorption in packed column by macroporous resins  

Microsoft Academic Search

Herein, two models, the general rate model taking into account convection, axial dispersion, external and intra-particle mass transfer resistances and particle size distribution (PSD) and the artificial neural network model (ANN) were developed to describe solanesol adsorption process in packed column using macroporous resins. First, Static equilibrium experiments and kinetic experiments in packed column were carried out respectively to obtain

Xueling Du; Qipeng Yuan; Jinsong Zhao; Ye Li

2007-01-01

135

Fundamental chromatographic equations designed for columns packed with very fine particles and operated at very high pressures applications to the prediction of elution times and the column efficiencies  

SciTech Connect

The wall temperatures of three Acquity-BEH-C{sub 18}columns (2.1 mm x 50, 100, and 150 mm) and the temperature of the incoming eluent were maintained constant at 289 K, using a circulating water heat exchanger. The retention times and the band broadening of naphtho[2,3-a]pyrene were measured for each column as a function of the flow rate applied. Pure acetonitrile was used as the eluent. The flow rate dependence of neither elution volumes nor bandwidths can be accounted for by classical models of retention and HETP, respectively, since these models assume columns to be isothermal. Because the heat generated by friction of the eluent against the column bed increases with increasing flow rate, the column bed cannot remain isothermal at high flow rates. This heat is evacuated radially and/or longitudinally by convection, conduction, and radiation. Radial and axial temperature gradients are formed, which are maximum and minimum, respectively, when the temperature of the column wall is kept uniform and constant. The retention times that we measured match well with the values predicted based on the temperature distribution along and across the column, which we calculated and on the temperature dependence of the retention for the same column operated isothermally (i.e., at very low flow rate). The rate of band spreading varies along non-isothermal columns, so the HETP can only be defined locally. It is a function of the axial coordinate. A new contribution is needed to account for the radial thermal heterogeneity of the column, hence the radial distribution of the flow velocities, which warps the elution band. A new model, based on the general dispersion theory of Aris, allows a successful prediction of the unusually large bandwidths observed with columns packed with fine particles, operated at high flow rates, hence high inlet pressures.

Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

2008-01-01

136

Unsplittable Flow in Paths and Trees and Column-Restricted Packing Integer Programs  

NASA Astrophysics Data System (ADS)

We consider the unsplittable flow problem (UFP) and the closely related column-restricted packing integer programs (CPIPs). In UFP we are given an edge-capacitated graph G = (V,E) and k request pairs R 1, ..., R k , where each R i consists of a source-destination pair (s i ,t i ), a demand d i and a weight w i . The goal is to find a maximum weight subset of requests that can be routed unsplittably in G. Most previous work on UFP has focused on the no-bottleneck case in which the maximum demand of the requests is at most the smallest edge capacity. Inspired by the recent work of Bansal et al. [3] on UFP on a path without the above assumption, we consider UFP on paths as well as trees. We give a simple O(logn) approximation for UFP on trees when all weights are identical; this yields an O(log2 n) approximation for the weighted case. These are the first non-trivial approximations for UFP on trees. We develop an LP relaxation for UFP on paths that has an integrality gap of O(log2 n); previously there was no relaxation with o(n) gap. We also consider UFP in general graphs and CPIPs without the no-bottleneck assumption and obtain new and useful results.

Chekuri, Chandra; Ene, Alina; Korula, Nitish

137

Evaluation of a subsurface oxygenation technique using colloidal gas aphron injections into packed column reactors  

SciTech Connect

Bioremediation may be a remedial technology capable of decontaminating subsurface environments. The objective of this research was to evaluate the use of colloidal gas aphron (CGA) injection, which is the injection of micrometer-size air bubbles in an aqueous surfactant solution, as a subsurface oxygenation technique to create optimal growth conditions for aerobic bacteria. Along with this, the capability of CGAs to act as a soil-washing agent and free organic components from a coal tar-contaminated matrix was examined. Injection of CGAs may be useful for remediation of underground coal gasification (UCG) sites. Because of this, bacteria and solid material from a UCG site located in northeastern Wyoming were used in this research. Colloidal gas aphrons were generated and pumped through packed column reactors (PCRS) containing post-burn core materials. For comparison, PCRs containing sand were also studied. Bacteria from this site were tested for their capability to degrade phenol, a major contaminant at the UCG site, and were also used to bioaugment the PCR systems. In this study we examined: (1) the effect of CGA injection on dissolved oxygen concentrations in the PCR effluents, (2) the effect of CGA, H[sub 2]O[sub 2], and phenol injections on bacterial populations, (3) the stability and transport of CGAs over distance, and (4) CGA injection versus H[sub 2]O[sub 2] injection as an oxygenation technique.

Wills, R.A.; Coles, P.

1991-11-01

138

Evaluation of a subsurface oxygenation technique using colloidal gas aphron injections into packed column reactors  

SciTech Connect

Bioremediation may be a remedial technology capable of decontaminating subsurface environments. The objective of this research was to evaluate the use of colloidal gas aphron (CGA) injection, which is the injection of micrometer-size air bubbles in an aqueous surfactant solution, as a subsurface oxygenation technique to create optimal growth conditions for aerobic bacteria. Along with this, the capability of CGAs to act as a soil-washing agent and free organic components from a coal tar-contaminated matrix was examined. Injection of CGAs may be useful for remediation of underground coal gasification (UCG) sites. Because of this, bacteria and solid material from a UCG site located in northeastern Wyoming were used in this research. Colloidal gas aphrons were generated and pumped through packed column reactors (PCRS) containing post-burn core materials. For comparison, PCRs containing sand were also studied. Bacteria from this site were tested for their capability to degrade phenol, a major contaminant at the UCG site, and were also used to bioaugment the PCR systems. In this study we examined: (1) the effect of CGA injection on dissolved oxygen concentrations in the PCR effluents, (2) the effect of CGA, H{sub 2}O{sub 2}, and phenol injections on bacterial populations, (3) the stability and transport of CGAs over distance, and (4) CGA injection versus H{sub 2}O{sub 2} injection as an oxygenation technique.

Wills, R.A.; Coles, P.

1991-11-01

139

Cotransport of clay colloids and viruses in water saturated columns packed with glass beads  

NASA Astrophysics Data System (ADS)

This study is focused on the cotransport of clay colloids and viruses in saturated columns packed with glass beads. Bacteriophages MS2 and ?X174 were used as model viruses, and kaolinite (kGa-1b) and montmorillonite (STx-1b) as model colloids. Virus and clay transport as well as virus-clay cotransport were examined at three pore water velocities (0.38, 0.74, and 1.21 cm/min). The results indicated that the mass recovery of viruses and clay colloids decreased as the pore water velocity decreased; whereas, for the cotransport experiments no clear trend was observed. Temporal moments of the breakthrough concentrations suggested that, in the absence of clay colloids, both MS2 and ?X174 traveled faster than the conservative tracer only at the highest pore water velocity tested. For the other two velocities both viruses were slightly retarded. The presence of clays significantly influenced the irreversible virus deposition onto glass beads. Both MS2 and ?X174 were attached in greater amounts onto KGa-1b than STx-1b. Also, MS2 exhibited greater affinity than ?X174 for both clays. The results suggest that Lewis acid-base interactions worked to the advantage of clay colloid attachment but did not significantly affect virus attachment onto glass beads. Schematic illustration of the six concentration components involved in cotransport experiments of this study.

Chrysikopoulos, C.; Syngouna, V. I.

2012-12-01

140

Design concept of a cryogenic distillation column cascade for a ITER scale fusion reactor  

NASA Astrophysics Data System (ADS)

A column cascade has been proposed for the fuel cycle of a ITER scale fusion reactor. The proposed cascade consists of three columns and has significant features: either top or bottom product is prior to the other for each column; it is avoided to withdraw side streams as products or feeds of down stream columns; and there is no recycle steam between the columns. In addition, the product purity of the cascade can be maintained against the changes of flow rates and compositions of feed streams just by adjusting the top and bottom flow rates. The control system has been designed for each column in the cascade. A key component in the prior product stream was selected, and the analysis method of this key component was proposed. The designed control system never brings instability as long as the concentration of the key component is measured with negligible time lag. The time lag for the measurement considerably affects the stability of the control system. A significant conclusion by the simulation in this work is that permissible time for the measurement is about 0.5 hour to obtain stable control. Hence, the analysis system using the gas chromatography is valid for control of the columns.

Yamanishi, Toshihiko; Enoeda, Mikio; Okuno, Kenji

1994-07-01

141

Development of dynamic models of reactive distillation columns for simulation and determination of control  

E-print Network

controllers of PID type were designed between the paired variables found from RGA and the controllers were implemented on the column model. Both servo and regulatory problems have been considered and tested....

Chakrabarty, Arnab

2005-02-17

142

Effect of gravity on colloid transport through water-saturated columns packed with glass beads: modeling and experiments.  

PubMed

The role of gravitational force on colloid transport in water-saturated columns packed with glass beads was investigated. Transport experiments were performed with colloids (clays: kaolinite KGa-1b, montmorillonite STx-1b). The packed columns were placed in various orientations (horizontal, vertical, and diagonal) and a steady flow rate of Q = 1.5 mL/min was applied in both up-flow and down-flow modes. All experiments were conducted under electrostatically unfavorable conditions. The experimental data were fitted with a newly developed, analytical, one-dimensional, colloid transport model. The effect of gravity is incorporated in the mathematical model by combining the interstitial velocity (advection) with the settling velocity (gravity effect). The results revealed that flow direction influences colloid transport in porous media. The rate of particle deposition was shown to be greater for up-flow than for down-flow direction, suggesting that gravity was a significant driving force for colloid deposition. PMID:24857560

Chrysikopoulos, Constantinos V; Syngouna, Vasiliki I

2014-06-17

143

High Performance Liquid Chromatography Separations Using Short Columns Packed with Spherical ODS Particles. II. Effect of Mobile Phase Composition on Resolution  

Microsoft Academic Search

The effect of instrumental parameters, mobile phase composition, and flow rate on high performance liquid chromatography separations using 3 cm, 5 cm, and 10 cm columns packed with 3y spherical ODS materials is discussed. The results indicate that when instrumental parameters were optimized, the 10 cm column gave better separation than the shorter columns under the same experimental conditions. However,

Haleem J. Issaq

1984-01-01

144

Removal of mixtures of acetaldehyde and propionaldehyde from waste gas in packed column with immobilized activated sludge gel beads.  

PubMed

The removal of mixed acetaldehyde and propionaldehyde as a model of the binary contaminants in waste gas was studied in the packed column containing the immobilized activated sludge gel beads together with the hollow plastic balls developed for the removal of a single aldehyde in the previous work. The rate of each aldehyde biodegradation by the gel beads in the aldehydes mixture was expressed by the Michaelis-Menten type rate equation with an inhibitory term due to the other coexistent aldehyde. The kinetic parameters involved were found to be the same as those determined previously for biodegradation of a single aldehyde. A model for prediction of removal of each aldehyde in the packed column was developed assuming that each aldehyde dissolved in the aqueous phase within the gel bead was biodegraded according to the above rate equation with no mass transfer effect. The packed column was stable and efficient for removal of the binary aldehydes mixture with a very low pressure drop for gas flow due to a reduced gel beads bed compaction by the hollow plastic balls. Removal of each aldehyde decreased with increasing the inlet aldehyde concentrations since each biodegradation rate itself approached asymptotically the maximum one with increase in each aldehyde concentration. The observed removals for each aldehyde in the aldehydes mixture agreed well with those calculated from the design equations developed. The contact efficiency of gel beads with the waste gas stream was estimated to be the same value of 0.24 as in the previous work, supporting that the efficiency was specific to the geometrical and physical properties of the packed column used. PMID:11356366

Ibrahim, M A.; Mizuno, H; Yasuda, Y; Fukunaga, K; Nakao, K

2001-07-01

145

Comparison of Packed Beds and Qiagen Columns for Recovering Trace Amounts of B. anthracis DNA from Liquid Suspensions  

Microsoft Academic Search

The goal of this work was to optimize and evaluate LLNL's in-bed amplification technology to improve the level of detection for suspensions containing trace amounts of anthracis DNA. The binding\\/cleaning performance of the packed bed is compared to the conventional commercial approach; Qiagen column cleanup and elution, followed by detection through an ex-situ amplification process. Five liquid suspensions were spiked

K Sorensen; E Arroyo; A Erler; A T Christian; D Camp; E K Wheeler

2006-01-01

146

Packed-bed sorption of copper using spent animal bones: factorial experimental design, desorption and column regeneration  

Microsoft Academic Search

A two-level factorial experimental design method has been proposed to investigate the influence of the operating parameters in a packed-bed adsorption column. This technique has been applied to quantify the influence of bed-depth, influent flow rate, and influent metal concentration on break-through time during the removal of copper from aqueous solutions using spent animal bones. A factorial model has been

Sameer Al-Asheh; Nabil Abdel-Jabar; Fawzi Banat

2002-01-01

147

Biosorption of lead(II) and cadmium(II) by protonated Sargassum glaucescens biomass in a continuous packed bed column  

Microsoft Academic Search

Biosorption of lead(II) and cadmium(II) from aqueous solutions by protonated Sargassum glaucescens biomass was studied in a continuous packed bed column. The selective uptake of Pb2+ and Cd2+ was investigated in a binary system with initial concentration of 1mM for each metal ion. The selective uptake capacities of Pb2+ and Cd2+ at complete exhaustion point were obtained 1.18 and 0.22mmol\\/g,

Kazem Naddafi; Ramin Nabizadeh; Reza Saeedi; Amir Hossein Mahvi; Forough Vaezi; Kamyar Yaghmaeian; Azar Ghasri; Shahrokh Nazmara

2007-01-01

148

Thermally Coupled Distillation  

Microsoft Academic Search

This paper presents a brief overview in the design of mixed thermally coupled-heat integrated distillation sequences. The approach considers from conventional columns (each distillation column with a condenser and a reboiler) to fully thermally coupled systems (only one reboiler and one condenser in the entire system). The advantages and disadvantages of thermally coupled distillation in comparison with conventional columns are

José A. Caballero

2009-01-01

149

Effects of Distillation System and Yeast Strain on the Aroma Profile of Albariño (Vitis vinifera L.) Grape Pomace Spirits.  

PubMed

Orujo is a traditional alcoholic beverage produced in Galicia (northwest Spain) from distillation of grape pomace, a byproduct of the winemaking industry. In this study, the effect of the distillation system (copper charentais alembic versus packed column) and the yeast strain (native yeast L1 versus commercial yeast L2) on the chemical and sensory characteristics of orujo obtained from Albariño (Vitis vinifera L.) grape pomace has been analyzed. Principal component analysis, with two components explaining 74% of the variance, is able to clearly differentiate the distillates according to distillation system and yeast strain. Principal component 1, mainly defined by C6-C12 esters, isoamyl octanoate, and methanol, differentiates L1 from L2 distillates. In turn, principal component 2, mainly defined by linear alcohols, linalool, and 1-hexenol, differentiates alembic from packed column distillates. In addition, an aroma descriptive test reveals that the distillate obtained with a packed column from a pomace fermented with L1 presented the highest positive general impression, which is associated with the highest fruity and smallest solvent aroma scores. Moreover, chemical analysis shows that use of a packed column increases average ethanol recovery by 12%, increases the concentration of C6-C12 esters by 25%, and reduces the concentration of higher alcohols by 21%. In turn, L2 yeast obtained lower scores in the alembic distillates aroma profile. In addition, with L1, 9% higher ethanol yields were achieved, and L2 distillates contained 34%-40% more methanol than L1 distillates. PMID:25307564

Arrieta-Garay, Y; Blanco, P; López-Vázquez, C; Rodríguez-Bencomo, J J; Pérez-Correa, J R; López, F; Orriols, I

2014-10-29

150

Rapid development of core-shell column technology: accurate measurements of the intrinsic column efficiency of narrow-bore columns packed with 4.6 down to 1.3 ?m superficially porous particles.  

PubMed

The intrinsic heights equivalent to a theoretical plate (HETPs) of 31 narrow-bore and wide-bore columns packed with four different brands of core-shell particles were accurately measured on an optimized vHPLC instrument (1290 Infinity system) that has an extra-column volume variance of 13.6±0.3 ?L(2). These results were derived from the slopes of the linear plots of the apparent plate heights of each column versus the reciprocal of (1+k')(2) for seven homologous compounds with a linear regression coefficient larger than 0.999. The results show that the kinetic performance of narrow-bore columns packed with core-shell particles increases almost linearly with decreasing particle diameter. The optimum reduced plate heights increase slightly from 1.6 to 1.9 with decreasing particle sizes from 4.6 to 1.3 ?m. This confirms that wide-bore columns provide better efficiencies than narrow-bore columns. PMID:24529958

Gritti, Fabrice; Guiochon, Georges

2014-03-14

151

Experimental evidence of the influence of the surface chemistry of the packing material on the column pressure drop in reverse-phase liquid chromatography  

Microsoft Academic Search

The permeabilities of six columns packed with different packing materials (neat silica, C1 endcapped silica at 3.92?? mol\\/m2, C18 bonded and endcapped silica with 0.42, 1.01, 2.03, and 3.15?? mol\\/m2 of C18 bonded chains) were measured. All these materials derive from the same batch of spherical particles, 5?? m in diameter. The columns have the same tube inner diameter (?=0.460±0.003

Fabrice Gritti; Georges Guiochon

2006-01-01

152

Capillary-electrochromatographic separations with copolymeric reversed-stationary phase and ion-exchanger-packed columns  

Microsoft Academic Search

A macroporous, spherical, 7 ?m, polystyrene–divinylbenzene (PS–DVB), reversed-phase adsorbent (PRP-1) was evaluated as a stationary phase for the capillary electrochromatographic (CEC) separation of neutral, acidic, and basic analytes of pharmaceutical interest. Electroosmotic flow (EOF) for a PRP-1 packed capillary is nearly constant over the pH 2 to 10 range and is higher than for a silica-based C18 packed capillary on

Yi Liu; Donald J Pietrzyk

2001-01-01

153

Particle-packed column versus silica-based monolithic column for liquid chromatography-electrospray-linear ion trap-tandem mass spectrometry multiallergen trace analysis in foods.  

PubMed

A bicarbonate buffer-based extraction method for the simultaneous analysis of five nut allergens (Ana o 2, cashew-nut; Cor a 9, hazelnut; Pru 1, almond; Ara h3/4, peanut; Jug r 4, walnut) in cereals and biscuits using liquid chromatography-electrospray-linear ion trap-tandem mass spectrometry (LC-ESI-LIT-MS(2)) was developed and validated. The method was based on our earlier published LC-MS(2)-based method in a research frame aimed at the identification and determination of hidden allergens in foods by using selective biomarker peptides. A C18 particle-packed column and a silica-based C18 monolithic column were compared in terms of chromatographic performances, such as peak shape, resolution, analysis time and selectivity. The C18 particle-packed column exhibited better performances and was further used for method development and validation. By operating under MS(2) selected reaction monitoring (SRM) acquisition mode, linearity, limits of detection (LOD) and quantitation, trueness and precision were evaluated on breakfast samples enriched with a mix of the five nuts. Good linearity of the matrix matched-calibration curves was obtained and detection limit values generally varied from 14 to 55 mg nut/kg matrix. Recoveries were in the 76±4% to 94±3% range with RSD <15%. The capabilities of LIT to perform MS(n) fragmentation was exploited to improve selectivity of the analysis, and the LC-(SRM) MS(2) method was compared in terms of LOD, linearity, precision and accuracy with a LC-(SRM) MS(3) method. Finally, both the LC-MS(2) and LC-MS(3) methods were successfully applied to the analysis of nut traces in commercially available breakfast cereals and biscuits. PMID:21030028

Bignardi, Chiara; Elviri, Lisa; Penna, Andrea; Careri, Maria; Mangia, Alessandro

2010-11-26

154

Bilirubin removal from human plasma in a packed-bed column system with dye-affinity microbeads  

Microsoft Academic Search

A dye-ligand, Cibacron Blue F3GA, was covalently coupled with the poly(EGDMA-HEMA) microbeads. The affinity sorbent carrying 16.5 ?mol Cibacron Blue F3GA per gram polymer was then used to remove bilirubin from human plasma in a packed-bed column system. Bilirubin adsorption from human plasma on the unmodified poly(EGDMA-HEMA) microbeads was 0.32 mg\\/g, while much higher adsorption values, up to 24.2 mg\\/g,

Adil Denizli; Mustafa Kocakulak; Erhan Pi?kin

1998-01-01

155

Physical properties and structure of fine core-shell particles used as packing materials for chromatography relationships between particle characteristics and column performance  

SciTech Connect

The recent development of new brands of packing materials made of fine porous-shell particles, e.g., Halo and Kinetex, has brought great improvements in potential column efficiency, demanding considerable progress in the design of chromatographic instruments. Columns packed with Halo and Kinetex particles provide minimum values of their reduced plate heights of nearly 1.5 and 1.2, respectively. These packing materials have physical properties that set them apart from conventional porous particles. The kinetic performance of 4.6 mm I.D. columns packed with these two new materials is analyzed based on the results of a series of nine independent and complementary experiments: low-temperature nitrogen adsorption (LTNA), scanning electron microscopy (SEM), inverse size-exclusion chromatography (ISEC), Coulter counter particle size distributions, pycnometry, height equivalent to a theoretical plate (HETP), peak parking method (PP), total pore blocking method (TPB), and local electrochemical detection across the column exit section (LED). The results of this work establish links between the physical properties of these superficially porous particles and the excellent kinetic performance of columns packed with them. It clarifies the fundamental origin of the difference in the chromatographic performances of the Halo and the Kinetex columns.

Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

2010-01-01

156

Transverse bacterial migration induced by chemotaxis in a packed column with structured physical heterogeneity  

PubMed Central

The significance of chemotaxis in directing bacterial migration towards contaminants in natural porous media was investigated under groundwater flow conditions. A laboratory-scale column, with a coarse-grained sand core surrounded by a fine-grained annulus, was used to simulate natural aquifers with strata of different hydraulic conductivities. A chemoattractant source was placed along the central axis of the column to model contaminants trapped in the heterogeneous subsurface. Chemotactic bacterial strains, Escherichia coli HCB1 and Pseudomonas putida F1, introduced into the column by a pulse injection, were found to alter their transport behaviors under the influence of the attractant chemical emanating from the central source. For E. coli HCB1, approximately 18% more of the total population relative to the control without attractant exited the column from the coarse sand layer due to the chemotactic effects of ?-methylaspartate under an average fluid velocity of 5.1 m/d. Although P. putida F1 demonstrated no observable changes in migration pathways with the model contaminant acetate under the same flow rate, when the flow rate was reduced to 1.9 m/d, approximately 6~10% of the population relative to the control migrated from the fine sand layer towards attractant into the coarse sand layer. Microbial transport properties were further quantified by a mathematical model to examine the significance of bacterial motility and chemotaxis under different hydrodynamic conditions, which suggested important considerations for strain selection and practical operation of bioremediation schemes. PMID:19731698

Wang, Meng; Ford, Roseanne M.

2009-01-01

157

Development of a 3D Model for Packed Bed Liquid Chromatography in Micro-columns  

Microsoft Academic Search

One-dimensional models of column liquid chromatography are today widely applied due to some obvious advantages. These models are easy to set up, they can be computed very fast, and they can often predict experimental results reasonably well. However, one-dimensional chromatography models also have some serious disadvantages, mainly because the applied homogeneity assumptions neglect important information on flow conditions and concentration

Sebastian Schnittert; Remo Winz; Eric Von Lieres

2009-01-01

158

Report on Qiagen Columns with Precipitation versus Packed Bed Technology for Trace Amounts of DNA  

Microsoft Academic Search

The assured limit of detection (LOD), where 100% of the PCR assays are successful, for the Qiagen spin column is dramatically improved when combined with an ethanol precipitation step of the eluted sample. A detailed SOP for the ethanol precipitation was delivered as a separate report. A key finding in the precipitation work was to incubate the ethanol precipitation at

E K Wheeler; A M Erler; A Seiler

2008-01-01

159

Extraction of squalene from shark liver oil in a packed column using supercritical carbon dioxide  

SciTech Connect

Continuous extraction of squalene from shark liver oil using supercritical carbon dioxide was carried out in both laboratory and pilot scale plant. The shark liver oil contained around 50% by weight squalene, which was recovered as the main extract stream. The other major components in the oil were triglycerides, which were recovered as raffinate, and pristane, which was recovered as a second extract stream. Separation performance was determined as a function of temperature; pressure; oil to carbon dioxide flow rate ratio, packed height and type of packing; and reflux ratio. The pressure, temperature, and feed oil concentration of squalene determined the maximum loading of oil in carbon dioxide. The oil to carbon dioxide ratio determined the squalene concentration in both the product stream and raffinate stream. The ratio of oil flow rate to the flow rate of squalene required to just saturate carbon dioxide was found to be a useful correlating parameter for the oil loadings and product compositions. Of the three packings investigated, wire wool gave the best separation efficiency and Raschig rings the worst efficiency. Mass transfer correlations from the literature were used to estimate the number of transfer units (NTU) from experimental data and literature correlations. NTU`s from the experimental data were comparable to predictions at a pilot scale but were underpredicted at the laboratory scale. The use of reflux at the pilot scale enabled the concentration of squalene in the product stream to be increased from 92% by mass to a maximum of 99% by mass at fractionation conditions of 250 bar and 333 K.

Catchpole, O.J.; Kamp, J.C. von; Grey, J.B. [Industrial Research Limited, Lower Hutt (New Zealand)] [Industrial Research Limited, Lower Hutt (New Zealand)

1997-10-01

160

Computational study of a column generation algorithm for bin packing and cutting stock problems  

Microsoft Academic Search

.   This paper reports on our attempt to design an efficient exact algorithm based on column generation for the cutting stock\\u000a problem. The main focus of the research is to study the extend to which standard branch-and-bound enhancement features such\\u000a as variable fixing, the tightening of the formulation with cutting planes, early branching, and rounding heuristics can be\\u000a usefully incorporated

François Vanderbeck

1999-01-01

161

Transport of surfactant-facilitated multiwalled carbon nanotube suspensions in columns packed with sized soil particles.  

PubMed

Transport of carbon nanotubes (CNTs) in soil/sediment matrixes can regulate their potential eco-effects and has been however rarely studied. Herein, column experiments were conducted to investigate mobility of CNT suspensions stabilized by dodecylbenzenesulfonic acid sodium salt (SDBS), octyl-phenol-ethoxylate (TX-100) and cetylpyridinium chloride (CPC) in four soil samples with certain particle sizes. Humic acid was extracted from a soil sample and was coated on quartz sands to explore the effect of soil organic matter (SOM) on the mobility. Results showed that the positively-charged CPC-CNT was entirely retained in the columns while the negatively-charged SDBS-CNT and TX-100-CNT more or less broke through the columns. Pearson correlation analyses revealed that soil texture rather than SOM controlled the mobility. Electrostatic attraction to and/or precipitation on the grain surfaces together with the straining effect could explain the CNT retention. These novel results will help to understand the eco-effects of CNTs. PMID:24880534

Lu, Yinying; Yang, Kun; Lin, Daohui

2014-09-01

162

Comparison of Packed Beds and Qiagen Columns for Recovering Trace Amounts of B. anthracis DNA from Liquid Suspensions  

SciTech Connect

The goal of this work was to optimize and evaluate LLNL's in-bed amplification technology to improve the level of detection for suspensions containing trace amounts of anthracis DNA. The binding/cleaning performance of the packed bed is compared to the conventional commercial approach; Qiagen column cleanup and elution, followed by detection through an ex-situ amplification process. Five liquid suspensions were spiked with B.anthracis DNA in concentration series. These suspensions were: (1) water, (2) water with EDTA, (3) dirty water from carpet extraction, (4) dirty carpet extraction with phosphate buffered saline (PBS) plus 0.1% Tween 20 plus 0.1% gelatin, and (5) a subway aerosol collected in water. Each suspension matrix was spiked with DNA and injected (in replicate) into either Qiagen Microcolumns (using the kit processing instructions) or LLNL's packed bed (using the LLNL in-bed purification and amplification protocol). The process output was assayed by quantitative polymerase chain reaction (QPCR). Table ES-1 shows the level of DNA (pg per 100 uL of input suspension) that resulted in successful amplification for all reactions (X=Y), and the level for which at least one of the reactions was successful (X>0). For each suspension and DNA concentration, there were Y QPCR assays of which X showed successful amplification. LLNL's packed bed technology outperformed Qiagen Microcolumns for all five suspensions, typically by one order of magnitude in both the limit of assured detection (all reactions positive), and the lower limit of detection (some reactions positive).

Sorensen, K; Arroyo, E; Erler, A; Christian, A T; Camp, D; Wheeler, E K

2006-06-23

163

Use of a Packed-Column Bioreactor for Isolation of Diverse Protease-Producing Bacteria from Antarctic Soil  

PubMed Central

Seventy-five aerobic heterotrophs have been isolated from a packed-column bioreactor inoculated with soil from Antarctica. The column was maintained at 10°C and continuously fed with a casein-containing medium to enrich protease producers. Twenty-eight isolates were selected for further characterization on the basis of morphology and production of clearing zones on skim milk plates. Phenotypic tests indicated that the strains were mainly psychrotrophs and presented a high morphological and metabolical diversity. The extracellular protease activities tested were optimal at neutral pH and between 30 and 45°C. 16S ribosomal DNA sequence analyses showed that the bioreactor was colonized by a wide variety of taxons, belonging to various bacterial divisions: ?-, ?-, and ?-Proteobacteria; the Flexibacter-Cytophaga-Bacteroides group; and high G+C gram-positive bacteria and low G+C gram-positive bacteria. Some strains represent candidates for new species of the genera Chryseobacterium and Massilia. This diversity demonstrates that the bioreactor is an efficient enrichment tool compared to traditional isolation strategies. PMID:12620829

Wery, Nathalie; Gerike, Ursula; Sharman, Ajay; Chaudhuri, Julian B.; Hough, David W.; Danson, Michael J.

2003-01-01

164

Fibronectin purification from human plasma in a packed-bed column system with gelatin immobilized PHEMA microspheres.  

PubMed

Bioaffinity chromatography has a unique and powerful role that is used as a purification tool in the production of therapeutic plasma protein derivatives. In this study, a bioaffinity-ligand, i.e. gelatin, was covalently immobilized with PHEMA microspheres (150-200 microm in diameter). The affinity sorbent carrying 7.5 mg gelatin g(-1) polymer was then used to separate fibronectin from human plasma in a packed-bed column system. Fibronectin separation from human plasma on unmodified PHEMA microspheres was 0.45 mg g(-1), while much higher adsorption values, up to 21.8 mg g(-1), were obtained with gelatin-immobilized microspheres. The fibronectin adsorption capacity of the microspheres decreased with an increase in the recirculation rate of plasma. Fibronectin adsorption increased with decreasing temperature, and the maximum adsorption achieved at 4 degrees C (26.3 mg fibronectin g(-1)). Up to 94.7% of the adsorbed fibronectin was desorbed by using 2 M urea in the presence of 1 M sodium chloride as elution agent. The adsorption-desorption cycle was repeated ten times using the same affinity column. There was no remarkable reduction in the adsorption capacity of the gelatin-immobilized PHEMA microspheres. PMID:11469779

Kayirhan-Denizli, F; Arica, M Y; Denizli, A

2001-01-01

165

Fast chiral separation of drugs using columns packed with sub-2 microm particles and ultra-high pressure.  

PubMed

The use of columns packed with sub-2 microm particles in liquid chromatography with very high pressure conditions (known as UHPLC) was investigated for the fast enantioseparation of drugs. Two different procedures were evaluated and compared using amphetamine derivatives and beta-blockers as model compounds. In one case, cyclodextrins (CD) were directly added to the mobile phase and chiral separations were carried out in less than 5 min. However, this strategy suffered from several drawbacks linked to column lifetime and low chromatographic efficiencies. In the other case, the analysis of enantiomers was carried out after a derivatization procedure using two different reagents, 2,3,4-tri-O-acetyl-alpha-D-arabinopyranosyl isothiocyanate (AITC) and N-alpha-(2,4-dinitro-5-fluorophenyl)-L-alaninamide (Marfey's reagent). Separation of several amphetamine derivatives contained within the same sample was achieved in 2-5 min with high efficiency and selectivity. The proposed approach was also successfully applied to the enantiomeric purity determination of (+)-(S)-amphetamine and (+)-(S)-methamphetamine. Similar results were obtained with beta-blockers, and the separation of 10 enantiomers was carried out in less than 3 min, whereas the individual separation of several beta-blocker enantiomers was performed in 1 min or less. PMID:19544347

Guillarme, Davy; Bonvin, Gregoire; Badoud, Flavia; Schappler, Julie; Rudaz, Serge; Veuthey, Jean-Luc

2010-03-01

166

Evaluation by respirometry of the degradability of retort water using a shale ash and overburden packed column.  

PubMed

Oil shale processing produces an aqueous wastewater stream known as retort water. The fate of the organic content of retort water from the Stuart oil shale project (Gladstone, Queensland) is examined in a proposed packed bed treatment system consisting of a 1:1 mixture of residual shale from the retorting process and mining overburden. The retort water had a neutral pH and an average unfiltered TOC of 2,900 mg 1(-1). The inorganic composition of the retort water was dominated by NH4+. Only 40% of the total organic carbon (TOC) in the retort water was identifiable, and this was dominated by carboxylic acids. In addition to monitoring influent and effluent TOC concentrations, CO2 evolution was monitored on line by continuous measurements of headspace concentrations and air flow rates. The column was run for 64 days before it blocked and was dismantled for analysis. Over 98% of the TOC was removed from the retort water. Respirometry measurements were confounded by CO2 production from inorganic sources. Based on predictions with the chemical equilibrium package PHREEQE, approximately 15% of the total CO2 production arose from the reaction of NH4+ with carbonates. The balance of the CO2 production accounted for at least 80% of the carbon removed from the retort water. Direct measurements of solid organic carbon showed that approximately 20% of the influent carbon was held-up in the top 20cm of the column. Less than 20% of this held-up carbon was present as either biomass or as adsorbed species. Therefore, the column was ultimately blocked by either extracellular polymeric substances or by a sludge that had precipitated out of the retort water. PMID:16128388

Clarke, W P; Ho, N M; Taylor, M; Coombs, S; Bell, P R; Picaro, T

2005-08-01

167

Measurement Reconciliation and Interpretation in Packed Distillation Column Operation Teck C. Lee and Colin S. Howat, Ph.D.  

E-print Network

to be subsequently used as a test of the plant performance interpretation accuracy. In addition, a continuous, mass. Additionally, atypical measurements can be made to be subsequently used as a test of the plant performance, accuracy, and precision. Plant performance analysis, the primary steps of which are identification

Howat, Colin S. "Chip"

168

Continuous adsorption of natural organic matters in a column packed with carbon nanotubes  

PubMed Central

In the present study, continuous adsorption experiments were carried out in an adsorption column to survey the efficiency of the carbon nanotubes (CNTs) for removal of natural organic matters (NOMs) from aqueous solution. Parameters such as mass of CNTs, initial NOMs concentration were evaluated and also the breakthrough curves were obtained. Experiments performed with various initial NOMs concentration and various CNTs masses. The breakthrough period was longer at lower initial NOMs concentration. Increase of the initial NOMs concentration, expectedly, resulted in the faster saturation of the CNTs bed. The adsorption capacities for multi wall carbon nanotubes (MWCNT) and single wall carbon nanotubes (SWCNT) in highest initial NOMs concentration were 53.46 and 66.24 mg/g, respectively. The effect of amount of CNTs on breakthrough time and volume of treated water was investigated and resulted that with an increase in the mass of CNTs, breakthrough time occurs very late and the volume of treated water increased. These findings suggested that CNTs present a great potential in removal of NOMs from aqueous solutions. PMID:24499604

2013-01-01

169

Batch and continuous packed column studies of cadmium biosorption by Hydrilla verticillata biomass.  

PubMed

The removal of heavy metal ions by the nonliving biomass of aquatic macrophytes was studied. We investigated Cd biosorption by dry Hydrilla verticillata biomass. Data obtained in batch experiments indicate that H. verticillata is an excellent biosorbent for Cd. Cd was rapidly adsorbed and such adsorption reached equilibrium within 20 min. The initial pH of the solution affected Cd sorption efficiency. Results obtained from the other batch experiments conformed well to those obtained using the Langmuir model. The maximum adsorption capacity q(max) for H. verticillata was 15.0 mg/g for Cd. The breakthrough curve from the continuous flow studies shows that H. verticillata in the fixed-bed column is capable of decreasing Cd concentration from 10 to a value below the detection limit of 0.02 mg/l. The presence of Zn ions affected Cd biosorption. It can be concluded that H. verticillata is a good biosorbent for treating wastewater with a low concentration of Cd contaminants. PMID:17630121

Bunluesin, Sushera; Kruatrachue, Maleeya; Pokethitiyook, Prayad; Upatham, Suchart; Lanza, Guy R

2007-06-01

170

Affinity adsorption of adsorbates into spherical monodisperse and bidisperse porous perfusive and purely diffusive adsorbent particles packed in a column parameter estimation in the Laplace transform domain  

Microsoft Academic Search

A novel mathematical method for parameter estimation is proposed and used to estimate in the Laplace transform domain the values of the parameters that characterize the mechanisms of intraparticle diffusion and convection in spherical perfusive or purely diffusive adsorbent particles with a monodisperse or with a bidisperse porous structure when the adsorbent particles are packed in a column. The parameter

G. A. Heeter; A. I. Liapis

1997-01-01

171

Speed-resolution properties of columns packed with new 4.6 ?m Kinetex-C(18) core-shell particles.  

PubMed

The achievable separation speed and resolution of columns packed with the new 4.6 ?m Kinetex particles were characterized by their permeability and their plate heights, measured meticulously. Their specific permeabilities range between 1.81 and 1.95 × 10(-10)cm(2) and their external porosities between 0.394 and 0.405. The efficiencies of the eluted peaks measured by numerical integration of the whole band concentration provided minimum reduced plate heights for uracil (non-retained) and naphthalene (retained) between 1.3 and 1.5 (H=6.0-6.9 ?m) for two 4.6 mm × 150 mm replicate columns of Kinetex and between 1.6 and 2.0 (H=7.4-9.2 ?m) for two narrow-bore 2.1 mm × 150 mm replicate columns. The most efficient 4.6 mm × 150 mm Kinetex column shows a deviation of one reduced plate height h unit with respect to the infinite diameter column (no wall, no inlet, no outlet endfitting) at high speed. Eventually, the separation speed and the resolution of columns packed with 4.6 ?m core-shell Kinetex particles are better or equivalent to those of columns packed with 2.5 ?m fully porous particles for hold-up times larger than only 10s. These core-shell materials are virtually equivalent to the second generation of silica monolithic columns with the advantage of operating well at pressure drops larger than 200 bar. PMID:23384789

Gritti, Fabrice; Guiochon, Georges

2013-03-01

172

Biosurfactant-producing and oil-degrading Bacillus subtilis strains enhance oil recovery in laboratory sand-pack columns.  

PubMed

Microbial Enhanced Oil Recovery (MEOR) technology uses microorganisms and their metabolites to retrieve unrecoverable oil from mature reservoirs. In situ stimulation of biosurfactant-producing and oil-degrading microorganisms reduces the capillary forces retaining the oil inside the reservoir and decreases its viscosity, thus promoting oil flow and consequently production. In this work, a sand-pack column model was designed to simulate oil recovery operations and evaluate mobilization of residual oil by the selected microorganisms. Four different hydrocarbon mixtures and three Bacillus subtilis strains isolated from crude oil samples were used. Additional oil recoveries ranged from 6 to 24% depending on the hydrocarbon mixture and microorganism used. Biosurfactant production was observed with all the microorganisms and hydrocarbon mixtures studied. The oils recovered after incubation with B. subtilis isolates showed a reduction in the percentage of long-chain n-alkanes and lower viscosity when compared with the original oils. The results obtained suggest that stimulation of the selected B. subtilis strains in situ can contribute to mobilize entrapped oil in mature reservoirs. PMID:23911831

Gudiña, Eduardo J; Pereira, Jorge F B; Costa, Rita; Coutinho, João A P; Teixeira, José A; Rodrigues, Lígia R

2013-10-15

173

A simple and efficient frit preparation method for one-end tapered-fused silica-packed capillary columns in nano-LC-ESI MS.  

PubMed

A novel frit preparation method for one-end tapered-fused silica-packed capillary columns in nano-LC-ESI MS was developed. A hollow-fused silica capillary column with a tapered tip as nano-spray emitter was filled with 5 microm C(18) beads, and then a sintered frit about 0.25 mm in length was prepared at the tip by butane flame. A stainless steel protection tube with 0.5 mm id was used to control the length of the frit and to protect the packed C(18) beads behind the sintered frit during the sintering. C(18) sintered frits were evaluated by BSA tryptic digests with nano-LC-LTQ. The sintered frits did not produce post-column band broadening due to very small volume (about 0.2 nL) and did not produce adsorption to sample. The sintered frit columns had good separation reproducibility and separation performance compared with self-assembled particles frit columns and commercial columns. PMID:20162556

Tan, Feng; Chen, Shuo; Zhang, Yangjun; Cai, Yun; Qian, Xiaohong

2010-04-01

174

Comparison of general rate model with a new model--artificial neural network model in describing chromatographic kinetics of solanesol adsorption in packed column by macroporous resins.  

PubMed

Herein, two models, the general rate model taking into account convection, axial dispersion, external and intra-particle mass transfer resistances and particle size distribution (PSD) and the artificial neural network model (ANN) were developed to describe solanesol adsorption process in packed column using macroporous resins. First, Static equilibrium experiments and kinetic experiments in packed column were carried out respectively to obtain experimental data. By fitting static experimental data, Langmuir isotherm and Freundlich isotherm were estimated, and the former one was used in simulation coupled with general rate model considering better correlative coefficients. The simulated results showed that theoretical predictions of general rate model with PSD were well consistent with experimental data. Then, a new model, the ANN model, was developed to describe present adsorption process in packed column. The encouraging simulated results showed that ANN model could describe present system even better than general rate model. At last, by using the predictive ability of ANN model, the influence of each experimental parameter was investigated. Predicted results showed that with the increases of particle porosity and the ratio of bed height to inner column diameter (ROHD), the breakthrough time was delayed. On the contrary, an increase in feed concentration, flow rate, mean particle diameter and bed porosity decreased the breakthrough time. PMID:17289066

Du, Xueling; Yuan, Qipeng; Zhao, Jinsong; Li, Ye

2007-03-23

175

Catalytic distillation structure  

DOEpatents

Catalytic distillation structure is described for use in reaction distillation columns, and provides reaction sites and distillation structure consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and is present with the catalyst component in an amount such that the catalytic distillation structure consists of at least 10 volume % open space. 10 figs.

Smith, L.A. Jr.

1984-04-17

176

Preparation of tertiary amyl alcohol in a reactive distillation column. 1: Reaction kinetics, chemical equilibrium, and mass-transfer issues  

Microsoft Academic Search

The hydration of isoamylenes to produce 2-methyl-2-butanol (tert-amyl alcohol, or TAA) is strongly limited by chemical equilibrium to olefin conversions of less than 50%. The general goal of this work was to determine whether reactive distillation would be a valid method to enhance the yield of TAA. The first step was to study the reaction kinetics and chemical equilibrium, using

J. Castor González; James R. Fair

1997-01-01

177

Packed-column capillary electrochromatography and capillary electrochromatography-mass spectrometry using a lithocholic acid stationary phase  

PubMed Central

The preparation and characterization of a novel lithocholic acid (LCA)-based liquid crystalline (LC) stationary phase (SP) suitable for application in packed-column CEC and CEC coupled to MS is described. The extent of bonding reactions of LCA-SP was assessed using 1H-NMR, 13C-NMR and elemental analysis. This characterization is followed by application of the LCA-SP for separation of ?-blockers, phenylethylamines (PEAs), polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). Using the optimum mobile phase operating conditions (pH 3.0-4.5, 10 mM ammonium acetate, 85% v/v ACN), a comparison of the chromatographic ability of the aminopropyl silica phase vs. the LCA-bonded phase was conducted. The results showed improved selectivity for all test analytes using the latter phase. For example, the CEC-MS of ?-blockers demonstrated that the LCA-bonded phase provides separation of six out of seven ?-blockers, whereas the amino silica phase provides four peaks of several co-eluting ?-blockers. For the CEC-MS analysis of PEAs, the LCA-bonded phase showed improved resolution and different selectivity as compared to the aminopropyl phase. An evaluation of the retention trends for PEAs on both phases suggested that the PEAs were retained based on varying degree of hydroxyl substitution on the aromatic ring. In addition, the MS characterization shows several PEAs fragment in the electrospray either by loss of an alkyl group and/or by loss of H2O. Finally, the LCA-bonded phase displayed significantly higher separation selectivity for PAHs and PCBs as compared to the amino silica phase. PMID:18425746

Norton, Dean; Shamsi, Shahab A.

2009-01-01

178

Comparison of Tortuosity Values for MnCl2 and Bacterial Diffusion in a Packed Column Using Magnetic Resonance Imaging (MRI)  

NASA Astrophysics Data System (ADS)

Diffusion through porous media is dependent on the tortuous path of the solute and can be described using a path tortuosity, ? . In this study, we use magnetic resonance imaging (MRI) to analyze the diffusion of a conservative tracer and of bacteria through a packed column to compare predictions for porous-media tortuosity. MRI is a noninvasive imaging technique for visualizing changes in concentration in a packed column as a function of time. Manganese chloride, MnCl2, is a contrasting agent readily detected using MRI. Paramagnetic magnetite particles are attached to the surface of Pseudomonas putida F1 cells using an antibody, thereby enabling us to measure changes in bacterial density within the packed column. In separate experiments, MnCl2 and bacterial distributions within a column of glass-coated polystyrene beads are imaged using MRI, with a spatial resolution of 300 ?m. MnCl2 or bacteria labeled with magnetite are introduced into one half of a specially designed chromatography column packed with glass-coated polystyrene beads. Impinging flow is used to create an initial step change in concentration and diffusion is monitored over time using MRI. One-dimensional MnCl2 diffusion and bacterial random motility in porous media have the same mathematical form, with terms for tortuosity and diffusion or motility, respectively. Dbulk is the bulk aqueous diffusion coefficient for MnCl2, 1.24x10-5 cm2/sec, and ? bulk is the bulk motility coefficient for P. putida F1, 3.20x10-5 cm2/sec. Both sets of diffusion data are analyzed by fitting numerical simulations of model equations to experimental data and determining the column tortuosity, ? . We have found that the column tortuosity observed using MnCl2 diffusion data is an order of magnitude smaller than that observed using bacterial diffusion data. This discrepancy suggests that bacteria swimming through porous media may experience a more tortuous path than other diffusing solutes. We believe that at small pore diameters, the swimming behavior of bacteria causes them to interact with the particles in a manner similar to Knudsen diffusion and that this interaction may help to explain the increased tortuosity experienced by the bacteria. Mathematical analysis of this conclusion will be presented and discussed.

Olson, M. S.; Smith, J. A.; Ford, R. M.; Fernandez, E. J.

2002-12-01

179

Evaluation of the kinetic performance of new prototype 2.1mm×100mm narrow-bore columns packed with 1.6?m superficially porous particles.  

PubMed

The mass transfer mechanism in three prototype narrow-bore columns (2.1mm×100mm format) packed with 1.6?m superficially porous particles was investigated using different instruments. The heights equivalent to a theoretical plate of three small molecules were measured using a mixture of acetonitrile and water as the eluent. The values reported include the contributions of longitudinal diffusion, eddy dispersion, and the solid-liquid mass transfer resistance. The bulk diffusion coefficients of the analytes were measured using the capillary method, calibrated with thiourea in pure water. The reduced longitudinal diffusion coefficient was determined from the results of a series of peak parking experiments. The solid-liquid mass transfer resistance coefficient and the intra-particle diffusivities of the analytes in the porous region of the particles were estimated from Garnett-Torquato's model of effective diffusion in dense beds packed with core-shell particles. The eddy dispersion term, mostly due to trans-column and border effects, was obtained by subtracting the longitudinal diffusion and the solid-liquid mass transfer resistance terms from the total HETP obtained from the first and second central peak moments calculated by numerical integration (Simpson's approach) after baseline correction and systematic left and right cuts of the peak profiles. The results show that the eddy dispersion controls at least 66% of the overall column HETP for small molecules beyond the optimum velocity. This work illustrates how important it is to use ultra-low dispersive very high pressure liquid chromatography (vHPLC) systems to properly measure and to practically use the high efficiencies of narrow-bore columns packed with 1.6?m core-shell particles since these columns provide intrinsic efficiencies higher than 400,000 plates per meter. PMID:24572546

Gritti, Fabrice; Shiner, Stephen J; Fairchild, Jacob N; Guiochon, Georges

2014-03-21

180

Efficient control system for low-concentration inorganic gases from a process vent stream: application of surfactants in spray and packed columns.  

PubMed

Control of low-concentration pollutants from a semiconductor process vent stream using a wet-scrubbing technique is a challenging task to meet Taiwan environmental emission standards. An efficient wet-scrubber is designed on a pilot scale and tested to control low concentration acid and base waste-gas emission. The scrubber system consisted of two columns, i.e., a fine spray column [cutoff diameter (based on volume), Dv(50) = 15.63 microm; Sauter mean diameter (SMD) = 7.62 microm], which is especially efficient for NH3 removal as the pH of the spraying liquid is approximately 7 followed by a packed column with a scrubbing liquid pH approximately 9.0 mainly for acids removal. It is observed that use of the surfactants in low concentration about 10(-4) M and 10(-7) M in the spray liquid and in the scrubbing liquid, respectively, remarkably enhances the removal efficiency of the system. A traditional packed column (without the spray column and the surfactant) showed that the removal efficiencies of NH3, HF, and HCl for the inlet concentration range 0.2 to 3 ppm were (n = 5) 22.6+/-3.4%, 43.4+/-5.5%, and 40.4+/-7.4%, respectively. The overall efficiencies of the proposed system (the spray column and the packed column) in the presence of the surfactant in the spray liquid and in the scrubbing liquid forthese three species were found to increase significantly (n = 5) from 60.3+/-3.6 to 82.8+/-6.8%, 59.1+/-2.7 to 83.4+/-4.2%, and 56.2+/-7.3 to 81.0+/-6.7%, respectively. In this work, development of charge on the gas-liquid interface due to the surfactants has been measured and discussed. It is concluded that the presence of charge on the gas-liquid interface is the responsible factor for enhancement of the removal efficiency (mass-transfer in liquid phase). The effects of the type of surfactants, their chain length, concentration in liquid, etc. on the removal efficiency are discussed. Since the pilot tests were performed under the operating conditions similar to most of the wet-scrubbers operated in semiconductors manufacturing facilities for inorganic pollutants, this study can be applied to modify the existing wet-scrubbers to enhance the removal efficiencies, especially for low-concentration pollutants. PMID:15575298

Chein, Hungmin; Aggarwal, Shankar G; Wu, Hsin-Hsien

2004-11-01

181

Transport behavior of humic acid-modified nano-hydroxyapatite in saturated packed column: effects of Cu, ionic strength, and ionic composition.  

PubMed

The surfaces of nano-hydroxyapatite (nHAP) used for contaminated soil and groundwater remediation may be modified to render nHAP highly mobile in the subsurface. Humic acid (HA) is widely used to modify and stabilize colloid suspensions. In this work, column experiments were conducted to determine the effects of contaminant (e.g., Cu) concentration, ionic strength (IS), and ion composition (IC) on the transport behavior of HA-modified nHAP in saturated packed columns. IS and nature of the cation had strong effects on the deposition of nHAP, and the effect was greater for divalent than for monovalent cations. Divalent cations have a greater capacity to screen the surface charge of nHAP, and Ca(2+) bridges the HA-modified nHAP colloidal particles, which causes greater deposition. Moreover, Cu(2+) had a greater effect on the transport behavior than Ca(2+) due to their strong exchange with Ca(2+) of nHAP and its surface complexation with nHAP. The relative travel distance L(T), of the injected HA-modified nHAP colloids, ranges from less than one to several meters at varying Cu concentrations, ISs, and ICs in saturated packed columns. The results are crucial to evaluate the efficacy of nHAP on the remediation of contaminated soil and groundwater environments. PMID:21612786

Wang, Dengjun; Chu, Lingyang; Paradelo, Marcos; Peijnenburg, Willie J G M; Wang, Yujun; Zhou, Dongmei

2011-08-15

182

Reliability of computer-assisted method transfer between several column dimensions packed with 1.3-5?m core-shell particles and between various instruments.  

PubMed

In this contribution, the possibility to automatically transfer RPLC methods between different column dimensions and instruments was evaluated using commercial modelling software. The method transfer reliability was tested with loratadine and its 7 related pharmacopeial impurities. In this study, state-of-the-art columns packed with superficially porous particles of 5, 2.6, 1.7 and 1.3?m particles were exclusively employed. A fast baseline separation of loratadine and related impurities (Rs,min=2.49) was achieved under the best analytical conditions (i.e. column of 50mm×2.1mm, 1.3?m, 10-90% ACN in 5min, T=40°C, pH=3, F=0.5ml/min). This optimal method was successfully tested on columns packed with other particle sizes, namely 1.7 and 2.6?m, to reduce pressure drop. The selectivities and retentions remained identical, while the peak widths were logically wider, leading to a reduction of peak capacity from 203 to 181 and 159 on the 1.3, 1.7 and 2.6?m particles, respectively. On the minimum, the resolution was equal to 1.54 on the 50mm×2.1mm, 2.6?m stationary phase. Next to this, the method was transferred to columns of different lengths, inner diameters and particle sizes (100mm×3mm, 2.6?m or 150mm×4.6mm, 5?m). These columns were used on other LC instruments possessing larger dwell volumes. The modelling software employed for developing the original method was able to calculate the new gradient conditions to be used. The accuracy of prediction was excellent, as the average retention time errors between predicted and observed chromatograms were -0.11% and 0.45% when transferring the method to 100mm×3mm and 150mm×4.6mm columns, respectively. This work proves the usefulness and validity of HPLC modelling software for transferring methods between different instruments, column dimensions and/or flow rates. PMID:24603352

Kormány, Róbert; Fekete, Jen?; Guillarme, Davy; Fekete, Szabolcs

2014-06-01

183

Preparation of tertiary amyl alcohol in a reactive distillation column. 1: Reaction kinetics, chemical equilibrium, and mass-transfer issues  

SciTech Connect

The hydration of isoamylenes to produce 2-methyl-2-butanol (tert-amyl alcohol, or TAA) is strongly limited by chemical equilibrium to olefin conversions of less than 50%. The general goal of this work was to determine whether reactive distillation would be a valid method to enhance the yield of TAA. The first step was to study the reaction kinetics and chemical equilibrium, using a polymeric acid catalyst (Amberlyst-15). Acetone was identified as a suitable medium to enable single liquid phase operation and also to enhance the reaction rate. It was found that the intraparticle mass-transfer resistance is negligible at temperatures below 70 C. A kinetic expression, based on Langmuir-Hinshelwood formalism, is proposed. The forward and reverse reactions show first-order dependence on isoamylenes and TAA, respectively, while water is essentially an inhibitor of the reaction in both directions. The temperature effect on the forward reaction is quantified with an activation energy of 69.5 kJ/mol.

Gonzalez, J.C.; Fair, J.R. [Univ. of Texas, Austin, TX (United States). Separations Research Program] [Univ. of Texas, Austin, TX (United States). Separations Research Program

1997-09-01

184

Intermediate Vapor Expansion Distillation and Nested Enrichment Cascade Distillation  

E-print Network

Benedict. Manson. 1947. "Multistage Separation Processes". Transactions American Institute of Chemical Engineers. Vol. 43, No.2. Kayihan, Ferhan. 1980. "Optimum Distribution of Heat Load in Distillation Columns Using Intermediate Condensers... Benedict. Manson. 1947. "Multistage Separation Processes". Transactions American Institute of Chemical Engineers. Vol. 43, No.2. Kayihan, Ferhan. 1980. "Optimum Distribution of Heat Load in Distillation Columns Using Intermediate Condensers...

Erickson, D. C.

185

Combination of adsorption and biodegradation processes for textile effluent treatment using a granular activated carbon-biofilm configured packed column system.  

PubMed

The objective of this study was to investigate the feasibility of using a granular activated carbon-biofilm configured packed column system in the decolorization of azo dye Acid Orange 7-containing wastewater. The Acid Orange 7-degrading microbial from anaerobic sequencing batch reactor which treating the azo dye-containing wastewater for more than 200 d was immobilized on spent granular activated carbon (GAC) through attachment. The GAC-biofilm configured packed column system showed the ability to decolorize 100% of the azo dye when working at high loading rate of Acid Orange 7 at 2.1 g/(L x d) with treatment time of 24 h. It was observed that the decolorization rate increased along with the increasing of initial Acid Orange 7 concentrations, until it reached an optimum point at about 0.38 g/h with initial Acid Orange 7 concentrations of 1,150 mg/L and the decolorization rate tend to be declined beyond this concentration. PMID:18817074

Ong, SoonAn; Toorisaka, Eiichi; Hirata, Makoto; Hano, Tadashi

2008-01-01

186

Lipase-catalyzed reaction in the packed-bed reactor with continuous extraction column to overcome a product inhibition  

Microsoft Academic Search

The resolution of rac-?-methyl-?-propiothiolactone (rac-MPTL) was performed in a packed-bed reactor (PBR) using Pseudomonas cepacia lipase (PCL) in organic media to produce enantiopure (R)-MPTL. By comparing enzyme stability of three enzyme forms, i.e. commercial PCL powder, Celite-immobilized PCL, and cross-linked enzyme crystals of PCL (CLECs-PCL), Celite-immobilized PCL was chosen for the construction of PBR because of its comparable stability to

Sekyoo Jeong; Bum-Yeol Hwang; Juhan Kim; Byung-Gee Kim

2000-01-01

187

The Semi-Preparative Separation of Peptides on Reversed Phase Silica Packed into Radially Compressed Flexible-Walled Columns  

Microsoft Academic Search

The semi-preparative separation of underivatised peptide mixtures from the tryptic digestion of thyroid and pituitary proteins has been accomplished on a 10dp spherical octadecyl-silica stationary phase, Radial Pak A\\/C18, packed into flexible-walled polyethylene cartridges (10 × 0.8cm). With volatile ionic modifiers, such as ammonium bicarbonate, excellent resolution and peptide recoveries were obtained with this support

M. T. W. Hearn; B. Grego; C. A. Bishop

1981-01-01

188

Effects of structural and kinetic parameters on the performance of chromatographic columns packed with perfusive and purely diffusive adsorbent particles  

Microsoft Academic Search

A mathematical model describing dynamic adsorption in columns with spherical bidisperse perfusive or spherical bidisperse purely diffusive absorbent particles is used to study the effects of the structural parameters of the adsorbent particles and of the parameters of the adsorption mechanism on the performance of chromatographic systems involving the adsorption of bovine serum albumin onto anion-exchange porous adsorbent particles. Four

G. A. Heeter; A. I. Liapis

1996-01-01

189

Complexation behavior of mono- and disaccharides by the vinylbenzeneboronic acid-divinylbenzene copolymer resins packed in a high-performance liquid chromatographic column.  

PubMed

Using an HPLC column packed with monodispersed vinylbenzeneboronic acid-divinylbenzene (V-D) copolymer resins, the elution behaviors of the mono- and disaccharides were studied under different pH mobile phases. The monodispersed V-D copolymer resins were prepared by the copolymerization of 4-vinylbenzeneboronic acid and divinylbenzene in the presence of template silica gel particles (particle size: 5 microm; pore size: 10 nm), followed by dissolution of the template silica gel using a NaOH solution. Similarly, styrene-divinylbenzene (S-D) copolymer resins as the control resins were also synthesized. The transmission electron micrographs of these polymer resins revealed a good monodispersity. The complexation behavior of the saccharides was evaluated by comparison of the peak area eluted through the V-D column for that through the S-D column. Four aldopentoses (D-ribose, D-arabinose, D-xylose, and D-lyxose) and four aldohexoses (D-glucose, D-mannose, D-galactose, and D-talose) were retained completely at pH 11.9. Especially, ribose and talose were totally retained even under acidic and neutral conditions. For the disaccharides, unlike sucrose and maltose, palatinose was completely retained in basic mobile phases. PMID:19362721

Kitahara, Kei-Ichi; Noguchi, Yuji; Itoh, Satoshi; Chiba, Nobunao; Tohyama, Tasuku; Nagashima, Kunio; Hanada, Takako; Yoshihama, Isao; Arai, Sadao

2009-10-30

190

Method transfer for fast liquid chromatography in pharmaceutical analysis: application to short columns packed with small particle. Part II: gradient experiments.  

PubMed

Liquid chromatography (LC) is currently considered as the gold standard in pharmaceutical analysis. Today, there is an increasing need for fast and ultra-fast methods with good efficiency and resolution for achieving separations in a few minutes or even seconds. A previous article (i.e. method transfer for fast LC in pharmaceutical analysis. Part I: isocratic separation) described a simple methodology for performing a successful method transfer from conventional LC to fast and ultra-fast LC in isocratic mode. However, for performing complex separations, the gradient mode is often preferred. Thus, this article reports transfer rules for chromatographic separations in gradient mode. The methodology was applied for the impurity profiling of pharmaceutical compounds, following two strategies. A first approach, using short columns (20-50mm) packed with 3.5microm particles and optimized HPLC instrumentation (with reduced extra-column and dwell volumes), was applied for the separation of a pharmaceutical drug and eight related impurities. Special attention was paid to the dwell (gradient delay) volume, which causes the most detrimental effect for transferring a gradient method. Therefore, the dwell volume was simultaneously decreased with the column dead volume. Under optimal conditions, it was possible to reduce the analysis time by a factor of 10, with an acceptable loss in resolution since the column length reduction is less critical in gradient than isocratic mode. The second tested approach was Ultra Performance Liquid Chromatography (UPLC), where sub-2microm particles were used simultaneously with very high pressures (up to 1000bar). A complex pharmaceutical mixture containing 12 compounds was separated in only 1.5min allowing a reduction of the analysis time by a factor of 15 in comparison to a conventional method, with similar peak capacity. PMID:17703929

Guillarme, Davy; Nguyen, Dao T T; Rudaz, Serge; Veuthey, Jean-Luc

2008-02-01

191

Ammonia removal from wastewaters using natural Australian zeolite. 2. Pilot-scale study using continuous packed column process  

SciTech Connect

A pilot-scale process was designed and operated to investigate the continuous removal of ammonia from sewage using natural zeolite from Australia. The process consisted of a fixed-bed ion-exchange system operated in the downflow mode. Evaluation of the pilot process was initially undertaken for ammonia removal from tap water spiked with ammonium chloride to provide performance data in the absence of competing cations. The performance of the pilot process was then assessed using sewage as feed. Breakthrough curves were constructed for a range of treatment flow rates. Existing models for packed bed performance were shown to be able to predict the breakthrough behavior of the process. The results of a study are presented that show that Australian natural zeolite, clinoptilolite, may be successfully employed in a fixed-bed ion-exchange process to achieve high ammonia removal efficiencies from aqueous solution at rates commensurate with sand filtration. The rate of uptake of ammonium by the zeolite is sufficient to support a continuous high rate process.

Cooney, E.L.; Booker, N.A.; Shallcross, D.C.; Stevens, G.W.

1999-10-01

192

Preparation and evaluation of packed capillary columns for the separation of nucleic acids by ion-pair reversed-phase high-performance liquid chromatography.  

PubMed

Oligonucleotides and double stranded DNA fragments were separated in 200 microm I.D. capillary columns packed with micropellicular, octadecylated, 2.1 microm poly(styrene-divinylbenzene) particles by ion-pair reversed-phase high-performance liquid chromatography (IP-RP-HPLC). Both the length and the diameter of the connecting capillaries (150 x 0.020 mm I.D.) as well as the detection volume (3 nl) had to be kept to a minimum in order to maintain the high efficiency of this chromatographic separation system with peak widths at half height in the range of a few seconds. Three different types of frits, namely sintered silica particles, sintered octadecylsilica particles, and monolithic poly(styrene-divinylbenzene) (PS-DVB) frits were evaluated with respect to their influence on chromatographic performance. Best performance for the separation of oligonucleotides and long DNA fragments was observed with the PS-DVB frits, whereas the short DNA fragments were optimally resolved in columns terminated by octadecylsilica frits. The maximum loading capacity of 60 x 0.20 mm I.D. columns ranged from 20 fmol (7.7 ng) for a 587 base pair DNA fragment to 500 fmol (2.4 ng) for a 16-mer oligonucleotide. Lower mass- and concentration detection limits in the low femtomol and low nanomol per liter range, respectively, make capillary IP-RP-HPLC with UV absorbance detection highly attractive for the separation and characterization of minute amounts of synthetic oligonucleotides, DNA restriction fragments, and short tandem repeat sequences amplified by polymerase chain reaction. PMID:11043584

Oberacher, H; Krajete, A; Parson, W; Huber, C G

2000-09-29

193

Packed bed column fermenter and kinetic modeling for upgrading the nutritional quality of coffee husk in solid-state fermentation.  

PubMed

Studies were carried out to evaluate solid-state fermentation (SSF) for the upgradation of the nutritional quality of coffee husk by degrading the caffeine and tannins present in it. SSF was carried out by Aspergillus niger LPBx in a glass column fermenter using factorial design experiments and surface response methodology to optimize bioprocess parameters such as the substrate pH and moisture content and aeration rate. The first factorial design showed that the moisture content of the substrate and aeration rate were significant factors for the degradation of toxic compounds, which was confirmed by the second factorial design too. The kinetic study showed that the degradation of toxic compounds was related to the development of the mold and its respiration and also to the consumption of the reducing sugars present in coffee husk. From the values obtained experimentally for the oxygen uptake rate and CO(2) evolved, the system determined a biomass yield (Y(x/o)) of 3.811 (g of biomass).(g of consumed O(2))(-1) and a maintenance coefficient (m) of 0.0031 (g of consumed O(2)).(g biomass of biomass)(-1).h(-1). The best results on the degradation of caffeine (90%) and tannins (57%) were achieved when SSF was carried out with a 30 mL.min(-1) aeration rate using coffee husk having a 55% initial moisture content. The inoculation rate did not affect the metabolization of the toxic compounds by the fungal culture. After SSF, the protein content of the husk was increased to 10.6%, which was more than double that of the unfermented husk (5.2%). PMID:11735442

Brand, D; Pandey, A; Rodriguez-Leon, J A; Roussos, S; Brand, I; Soccol, C R

2001-01-01

194

Combination of a sub-3 ?m superficially porous particle packed column with charged aerosol detection for the simple and sensitive measurement of nine macrolides in human urine.  

PubMed

Due to the lack of chromophores in many macrolides, analytical methods based on mass spectrometry and electrochemical detection coupled to liquid chromatography have been suggested to be suitable for the quantification of macrolides in complex matrices. In this study, a simple and sensitive analytical method was established for the simultaneous measurement of nine macrolides in human urine by combining a sub-3 ?m superficially porous particle packed column with charged aerosol detection. After thorough investigation of various sample preparation methods, including two liquid-liquid extraction methods and four solid-phase extraction methods, HLB solid-phase extraction was selected and further optimized. Absolute recovery of the optimized sample preparation method ranged from 99.5-110.2%, indicating its very high extraction/clean-up efficiency. For chromatography, parameters influencing macrolide separation were systematically optimized, and the resulting conditions allowed baseline separation of nine macrolides within 24 min using a very simple mobile phase. The established method was validated for linearity, limit of detection, limit of quantification, absolute recovery, and precision. Based on its limit of detection (0.025-0.100 ?g/mL), the method had similar or greater sensitivity than most methods based on electrochemical detection. It was found that the current method was appropriate for application to real human urine samples after drug administration. PMID:25155847

Jia, Shaodong; Song, In Gi; Jeong, Kyung Min; Li, Jing; Park, Jeong Hill; Lee, Jeongmi; Kwon, Sung Won

2014-10-01

195

Repeatability of the efficiency of columns packed with sub-3?m core-shell particles: Part III. 2.7?m Poroshell 120 EC-C18 particles in 4.6mm and 2.1mm × 100mm column formats.  

PubMed

As part of an investigation of the column-to-column repeatability of the efficiency of columns packed with sub-3?m shell particles, the parameters of the mass transfer kinetics of twelve columns packed with the same batch of 2.7?m Poroshell 120 EC-C(18) particles (Agilent Technologies, Little Fall, DE, USA) were sequentially measured, using columns provided by the manufacturers that were representative of the efficiency distribution given by the quality test control. The reduced longitudinal diffusion term (B) was measured using the peak parking (PP) method; the reduced solid-liquid mass transfer resistance term (C) was given by a combination of the PP results and the most accurate model of effective diffusion in ternary composite materials. The overall eddy diffusion term (A) was obtained by subtraction of these two HETP terms from the overall reduced HETP derived from the peak moments measured by numerical integration of the entire peak profiles. The results demonstrate that the dispersion of the column efficiencies is a result of the random nature of the packing process and the eddy diffusion term resulting from the lack of homogeneity of the column bed. At the highest reduced velocity achieved for small analytes, the relative standard deviations (RSD) of the eddy diffusion term for the 2.1mm I.D. columns were ca. 3 and 11% (with average values h(eddy)= 2.5 and 13.5) for naphthalene (k=3) and uracil (k=0), respectively. For the 4.6mm I.D. columns, these RSDs were 5 and 13%, respectively, with average values h(eddy)= 1.4 and 2.9. For insulin at reduced velocities as high as 160, the RSDs of the total reduced plate heights were 3 and 8% for the 2.1 and 4.6mm I.D. columns, respectively. PMID:22683189

Gritti, Fabrice; Guiochon, Georges

2012-08-24

196

Catalytic Distillation  

E-print Network

Catalytic Distillation' refers to a chemical process which performs both a catalyzed reaction and primary fractionation of the reaction components simultaneously. A structured catalyst which also is an effective distillation component has been...

Smith, L. A., Jr.; Hearn, D.; Wynegar, D. P.

1984-01-01

197

Semicontinuous, pressure-swing distillation  

SciTech Connect

The merits of semicontinuous, pressure-swing, azeotropic distillation are examined. In continuous operation, two columns at different pressures are fed streams having compositions on opposite sides of the azeotropic compositions. The distillates, which approach the azeotropic compositions at high and low pressure, are cycled between the columns. In contrast, semicontinuous operation involves only a single distillation column, which has lower investment costs and, when the mixture to be separated is changed, shorter downtimes. An optimal-control algorithm is employed to determine desirable campaigns, and to schedule pressure switch-over policies. Simulation results for the dehydration of tetrahydrofuran, involving a pressure-sensitive azeotrope, indicate that switch-over between steady states occurs quickly with on-spec product removed during 93% of the campaign. The column achieves production rates near 89% of the maximum throughput of a single column in the continuous process and shows superior performance when compared to reverse-batch operation.

Phimister, J.R.; Seider, W.D.

2000-01-01

198

Evaluation of monolithic and sub 2 microm particle packed columns for the rapid screening for illicit drugs--application to the determination of drug contamination on Irish euro banknotes.  

PubMed

A study comparing recently available 100 x 3 mm id, 200 x 3 mm id monolithic reversed-phase columns with a 50 x 2.1 mm id, 1.8 microm particle packed reversed-phase columns was carried out to determine the most efficient approach (using traditional van Deemter analysis and a modern kinetic plot approach) for the rapid screening of samples for 16 illicit drugs and associated metabolites. A plot of column backpressure versus plate number (N) showed a significant advantage of using the monolithic phases, with the 20 cm monolithic column exhibiting a maximum 15,000 plates at a column backpressure of approximately 70 bar, compared to approximately 7000 plates at 150 bar for the 5 cm 1.8 microm particle packed column. Optimum linear velocities were found to be 0.40 mm s(-1), 0.52 mm s(-1) and 0.98 mm s(-1) for the three above columns, respectively. The 20 cm monolithic column was subsequently applied to the separation and determination of illicit drug contamination on Irish euro banknotes, using methanol extraction followed by LC-MS/MS. Method performance data showed that the new LC-MS/MS method was significantly more sensitive than previous GC-MS/MS based methods for this application, with detection limits in the pg note(-1) region, based upon a 20 microL standard injection. All of the notes examined tested positive for trace quantities of cocaine, with benzoylecgonine detected on 12 of the 45 notes sampled. Traces of heroin were also detected on three of the 45 notes. PMID:17325753

Bones, Jonathan; Macka, Mirek; Paull, Brett

2007-03-01

199

Effect of parallel segmented flow chromatography on the height equivalent to a theoretical plate. I-performance of 4.6mm×30mm columns packed with 3.0?m Hypurity-C18 fully porous particles.  

PubMed

The mass transfer kinetics in short and wide 4.6mm×30mm columns packed with 3.0?m Hypurity-C18 fully porous particles were measured for three different configurations of the inlet sample distribution and outlet sample collection: (1) both the inlet and outlet column endfittings are standard, (2) the inlet endfitting is standard while the outlet endfitting allows parallel segmentation of the exiting flow between a central and a peripheral region across the column diameter, and (3) both the inlet and outlet endfittings allow a parallel segmentation of the flow entering and exiting the column, respectively. The total reduced heights equivalent to a theoretical plate (HETP) were carefully measured, using the first and second central moments of the elution band profiles, obtained by its accurate numerical integration. The longitudinal diffusion term was measured at the lowest experimental reduced velocity applied. The solid-liquid mass transfer resistance was estimated from measurements of the intra-particle diffusivity using the Torquato's model of effective diffusion in packed beds. The trans-channel and short-range interchannel eddy diffusion HETP terms were taken from data obtained by solving numerically the Navier-Stokes equations and simulating advective-diffusive transport in computer-generated random sphere packings. The results clearly show that the trans-column eddy diffusion HETP term can account for up to 85% of the total intrinsic HETP (corrected for extra-column contributions) of the standard columns. Parallel segmented flow chromatography can reduce this contribution by half at high velocities, by eliminating most of the baseline peak tailing. This holds true irrespective of the retention factor of the analyte. It was found also that segmenting the inlet/outlet flow increases detection sensitivity by 25-50% for peaks with large to small retention factors, respectively. In practice, the advantage of parallel segmented flow chromatography in gradient elution (thin peak widths) is essentially limited by post-column bandspreading and diffusion in the dwell volume of the instrument used. Analyst should minimize post-column bandspreading (caused by connectors and detection cell volume) and synchronize the eluent composition in the peripheral and central inlet ports of the column, by using two separate pumps with appropriate dwell volumes. PMID:23706347

Gritti, Fabrice; Guiochon, Georges

2013-07-01

200

Simultaneous on-line preconcentration and determination of trace metals in environmental samples by flow injection combined with inductively coupled plasma mass spectrometry using a nanometer-sized alumina packed micro-column  

Microsoft Academic Search

A flow injection (FI) on-line preconcentration procedure by using a nanometer-sized alumina packed micro-column coupled to inductively coupled plasma mass spectrometry (ICP-MS) was described for simultaneous determination of trace metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) in the environmental samples. The effects of pH value, sample flow rate, preconcentration time, and interfering ions on the preconcentration

Jun Yin; Zucheng Jiang; Gang Chang; Bin Hu

2005-01-01

201

An extension of the multi-theta method to distillation columns and an almost band solution of the equilibrium stage problem  

E-print Network

application of the Newton-Raphson procedure for such thermodynamic functions, and thus convergence properties typical of this method were obtained. The extended multiple theta method was then applied to a distillation problem involving thermodynamic... of the Newton-Raphson method even when composition dependent thermodynamic functions are used. The particular set of variables and functions chosen in this work leads to a large Jacobian matrix that is easily solved due to its special structure, Several...

Gallun, Steven Eugene

2012-06-07

202

Petroleum distillates  

Microsoft Academic Search

This report provides data for the evaluation of the safety of certain petroleum distillate fractions used in commercial products to which consumers may be exposed. Chemical information and data on the toxicology, pharmacology and relevent biology are compiled on mixtures under the headings petroleum naphthas, distillate fuels, and mineral oils. Petroleum products find wide use in products available to the

J. Villaume; P. Walter; R. Levine; A. Craigmill; H. Schwartz

1976-01-01

203

Design of distillation sequences: from conventional to fully thermally coupled distillation systems  

Microsoft Academic Search

This work presents a novel superstructure optimization approach for the design of distillation sequences of zeotropic mixtures. The approach considers as alternatives from conventional sequences in which each final distillation column has a condenser and a reboiler, to fully thermally coupled distillation sequences going through all possible intermediate combinations. A two-stage procedure is proposed. In the first one, a sequence

José A. Caballero; Ignacio E. Grossmann

2004-01-01

204

Effect of parallel segmented flow chromatography on the height equivalent to a theoretical plate II - performances of 4.6mm×30mm columns packed with 2.6?m Accucore-C18 superficially porous particles.  

PubMed

The reduced trans-column (or long-range eddy dispersion) height equivalent to a theoretical plate (HETP) of short and wide 4.6mm×30mm columns packed with 2.6?m Accucore-C18 superficially porous particles was measured under conventional (no split flow) and parallel segmented (outlet and inlet) flow chromatography. The overall reduced HETP was derived from the true moments of the recorded concentration profiles. The longitudinal diffusion HETP term was measured at a very small flow rate (0.05mL/min). The solid-liquid mass transfer resistance was derived from the shell diffusivity, using the composite Garnett-Torquato model of effective diffusion in a heterogeneous system made of a dense packing of core-shell particles immersed in a continuous matrix (the eluent). The trans-channel and short-range interchannel eddy dispersion HETP terms were assumed to be equal to the calculated h data after solving the Navier-Stokes equation and simulating the advection-diffusion transport process. Experimental results confirmed that the optimum efficiency of these short columns was increased by a factor of about two. The ratio of the detection sensitivities on the PSFC stream and on a regular stream increased from 1 to 1.45 when the retention factor decreases from about 10 to 0.5. These phenomena are due to a strong reduction of the trans-column eddy dispersion HETP term. The system loses about 60% of the sample mass when only outlet skimming is carried out when the flow rate ratio of 55% is applied, as was done in this work. It loses about 50% of the sample when inlet/outlet segmentation is applied. In gradient elution, the peak capacity is increased by only 15%, due to post-column band spreading, which should imperatively be minimized when the outlet flow is split. PMID:24050598

Gritti, Fabrice; Guiochon, Georges

2013-11-01

205

Solar Distillation  

Microsoft Academic Search

\\u000a “Solar distillation” is a technology for producing potable water from brackish and underground water of low-quality at low\\u000a cost. It can reduce water-scarcity problems together with other water purification technologies. Solar distillation is analogous\\u000a to natural hydrological cycle. It uses an apparatus called a solar still in which water is evaporated using solar energy,\\u000a a form of renewable energy, and

Rahul Dev; Gopal Nath Tiwari

206

Control properties of thermally coupled distillation sequences for different operating conditions  

Microsoft Academic Search

The understanding of the dynamic behavior of distillation columns has received considerable attention due to the fact that distillation is one of the most widely used unit operations in chemical process industries. Thermally coupled distillation sequences (TCDS) can provide significant energy savings with respect to the operation of sequences based on conventional distillation columns. TCDS exhibit a complex structure, with

Juan Gabriel Segovia-hernández; Esteban Abelardo Hernández-vargas; Jorge Alberto Márquez-muñoz

2007-01-01

207

Method for packing chromatographic beds  

DOEpatents

Column chromatography beds are packed through the application of static force. A slurry of the chromatography bed material and a non-viscous liquid is filled into the column plugged at one end, and allowed to settle. The column is transferred to a centrifuge, and centrifuged for a brief period of time to achieve a predetermined packing level, at a range generally of 100-5,000 gravities. Thereafter, the plug is removed, other fixtures may be secured, and the liquid is allowed to flow out through the bed. This results in an evenly packed bed, with no channeling or preferential flow characteristics.

Freeman, David H. (Potomac, MD); Angeles, Rosalie M. (Germantown, MD); Keller, Suzanne (Rockville, MD)

1991-01-01

208

Development of standard operation procedures for the manufacture of n-octadecyl bonded silicas as packing material in certified reference columns for reversed-phase liquid chromatography  

Microsoft Academic Search

The development of standard operation procedures for the manufacture of a n-octadecyl bonded spherical silica packing from partially condensed tetraethoxysilane as silica source is described. The synthesis comprises five intermediate products and six synthesis steps which were examined according to their reproducibility and robustness. The results led to the optimisation of the manufacturing process for a n-octadecyl bonded silica. Correlations

C. du Fresne von Hohenesche; V Ehwald; K. K Unger

2004-01-01

209

A test to determine the nature and presence of the memory effect columns packed with the amylose tris(3,5-dimethylphenylcarbamate) stationary phase.  

PubMed

Acid/base mobile phase modifiers affect enantioseparations in ways that are not fully understood yet, for the lack of systematic studies. This makes chiral analysis of some pharmaceuticals difficult to reproduce. Once a column has been exposed to a modifier, the selectivity of certain pairs of enantiomers may change, for the better or the worse. We study the behavior of five enantiomeric pairs, three which are highly sensitive to the addition of certain modifiers and two that have little sensitivity to these modifiers. Their use permits the determination of the extent of the memory effect response on individual columns. The selectivity of 4-chlorophenylalanine methyl and ethyl ester, and of ketoprofen improve as a solution of ethanesulfonic acid is percolated through the column. As a result, these pairs are most useful for the determination of the extent of acid memory effect on a column. The selectivity of propranolol HCl and, to a lesser degree, Tröger's base increases as a solution of diisopropylethylamine is percolated through the column. The separation of each one of these five pairs is inversely affected by the percolation of the opposite acid/base solution. We used trans-stilbene oxide (TSO) as a 'standard' to determine the column stability because no memory effect is observed for it (its retention, enantioselectivity, and resolution remain constant). Understanding whether a column is under the influence of the memory effect is critical to both the analysis of pharmaceutical ingredients and to the development of preparative purification techniques for racemic mixtures. Thus, columns that were unreliable for method development and method transfer, due to the memory effect and a lack of proper solvent exposure records, can now be used. PMID:21798545

Putnam, Joel; Guiochon, Georges

2011-09-16

210

A simple method for systematic synthesis of thermally integrated distillation sequences  

Microsoft Academic Search

Thermodynamic approach to heat integration of processes involving separation of multicomponent mixtures is described. An integrability criterion based on geometrical presentation of distillation columns in temperature–enthalpy flow rate diagram was tested by rigorous simulation of distillation columns. The integrability criterion for distillation columns sequence was defined as the minimum sum of products of intracolumn temperatures and their heat flow rates

Gorazd Sobo?an; Peter Glavi?

2002-01-01

211

Distillations Podcast  

NSDL National Science Digital Library

Created by the folks at the Chemical Heritage Foundation, Distillations is an award-winning podcast that offers commentary and perspective on the past, present, and future of chemistry. The program is hosted by Meir Rinde and new episodes are issued every other Friday. The archive here contains over 150 podcasts with titles such as "Shipwrecks," "Sweat," and "Something in the Air." Visitors can also sort through the documents by category and learn about the Distillations staff. The archives date back to 2007, so there's plenty to explore and visitors are free to use the materials as they see fit. An episode or two might be the perfect way to keep a group of students intrigued by the world of chemistry.

2012-09-14

212

Effectiveness and longevity of a green/food waste derived compost packed column to reduce Cr(VI) contamination in groundwater.  

PubMed

PAS100 accredited compost derived from green and food waste sources was used to remediate groundwater containing Cr(VI) at a historically contaminated site in Falkirk, Scotland, UK. The compost was mixed with gravel at a ratio of 1:1 (v/v) to provide a reactive bedding material in an upflow column. The Cr(VI) concentration in the groundwater (inlet) ranged from 0.5 to 7.8 mg L(-1) during the 168 d trial period. After an acclimation period of 54 d, the flow rate was increased in the column from 5.8 to 8 mL min(-1). Cr(VI) in the outlet was less than 100 ?g L(-1) up to 134 d, after which the concentration steadily increased till 168 d. Compost analysis following completion of the trial confirmed that Cr(VI) was captured within the column. Anaerobic microbial reduction of Cr(VI) to Cr(III) was thought to be a key mechanism responsible for the longevity of the system to remove Cr(VI) from the groundwater. Requiring no additional organic carbon or nitrogen during the trial period, this setup represents a cost-effective treatment approach for low flow-through systems. PMID:21195546

Piau, C; Aspray, T J

2011-02-28

213

Distributive Distillation Enabled by Microchannel Process Technology  

SciTech Connect

The application of microchannel technology for distributive distillation was studied to achieve the Grand Challenge goals of 25% energy savings and 10% return on investment. In Task 1, a detailed study was conducted and two distillation systems were identified that would meet the Grand Challenge goals if the microchannel distillation technology was used. Material and heat balance calculations were performed to develop process flow sheet designs for the two distillation systems in Task 2. The process designs were focused on two methods of integrating the microchannel technology â?? 1) Integrating microchannel distillation to an existing conventional column, 2) Microchannel distillation for new plants. A design concept for a modular microchannel distillation unit was developed in Task 3. In Task 4, Ultrasonic Additive Machining (UAM) was evaluated as a manufacturing method for microchannel distillation units. However, it was found that a significant development work would be required to develop process parameters to use UAM for commercial distillation manufacturing. Two alternate manufacturing methods were explored. Both manufacturing approaches were experimentally tested to confirm their validity. The conceptual design of the microchannel distillation unit (Task 3) was combined with the manufacturing methods developed in Task 4 and flowsheet designs in Task 2 to estimate the cost of the microchannel distillation unit and this was compared to a conventional distillation column. The best results were for a methanol-water separation unit for the use in a biodiesel facility. For this application microchannel distillation was found to be more cost effective than conventional system and capable of meeting the DOE Grand Challenge performance requirements.

Arora, Ravi

2013-01-22

214

Hydrothermal carbonization of distiller’s grains  

Microsoft Academic Search

Wet distiller’s grains are intermediate byproducts of ethanol manufacture that have high moisture contents and require significant energy for drying and conversion into dry distiller’s grains. Hydrothermal carbonization was investigated as a wet process to provide alternative products, and chars were obtained in moderate yield that possessed high heats of combustion. The mechanism of char formation was also investigated employing

Steven M. Heilmann; Lindsey R. Jader; Michael J. Sadowsky; Frederick J. Schendel; Marc G. von Keitz; Kenneth J. Valentas

2011-01-01

215

Common screening approaches for efficient analytical method development in LC and SFC on columns packed with immobilized polysaccharide-derived chiral stationary phases.  

PubMed

Owing to their remarkable enantioselectivity, versatility, and stability, immobilized polysaccharide-based chiral stationary phases (CSPs) have been successfully integrated into the tool box of many research and industry groups for the separation of enantiomers or stereoisomers by liquid and supercritical fluid chromatography. Due to the structurally diverse range of compounds available, efficient method development for chiral separations utilizing such CSPs is a challenging subject. In this chapter, we will discuss simplified screening protocols and straightforward approaches to achieve chiral separations in HPLC and SFC using the column series CHIRALPAK™ IA, IB, IC, and ID in reasonable time frame and with limited experimental work and a high success rate. PMID:23283773

Franco, Pilar; Zhang, Tong

2013-01-01

216

Elution mechanism of polypeptides in reversed-phase liquid chromatography based on the critical threshold of organic solvent to induce abrupt change in adsorption capacity to the column packing.  

PubMed

Adsorption capacity of polypeptides to the column packing in a solution containing multiple organic solvents was found to be expressed by means of an fn value, which is the sum of the ratios of the content of each organic solvent in the solution to the critical content of each organic solvent to cause abrupt change in the adsorption capacity, and to change abruptly at the point where the fn value becomes 1. Additionally, our results indicate that each polypeptide is eluted by the eluent containing a specific organic solvent content regardless of gradient elution rate in reversed-phase liquid chromatography, and that total organic solvent content in the eluent containing polypeptides is equal to the critical content. Considering the power law relationship between the retention times and the gradient elution rates, our results suggest that the elution of each polypeptide in reversed-phase liquid chromatography is mainly controlled by abrupt change in the adsorption capacity induced by change in the organic solvent content of the eluent during a gradient elution process, and that the abrupt change repeats across the critical threshold while a polypeptide moves through the column, and as a result, each polypeptide is concentrated in the eluent with the critical threshold. PMID:17685410

Goda, Ryoya; Sudo, Kenichi

2008-01-01

217

Evaluation of copper speciation in model solutions of humic acid by mini-columns packed with Chelex-100 and new chelating agents: application to speciation of selected heavy metals in environmental water samples.  

PubMed

A solid-phase extraction procedure using mini-columns packed with Chelex-100 and two new chelating agents based on poly(vinyl chloride) functionalized with 3-ferrocenyl-3-hydroxydithioacrylic acid and N,N'-[1,1'-dithiobis(ethylene)]-bis(salicylideneimine) (H(2)sales) loaded on microcrystalline naphthalene, is reported. The columns were used to separate labile copper fractions in model solutions and in real samples with subsequent determination using electrothermal atomic absorption spectrometry (ETAAS). Various model solutions containing 20 microg L(-1) of Cu(2+) and 0.0, 0.2, 2.0 and 20.0 mg L(-1) of humic acid, respectively, and buffered to pH 6.0, 7.0 and 8.0 were considered. Results showed a decrease in labile copper fraction with increase in humic acid concentration. Application of the procedure to speciation of Cu, Ni, Zn and Pb in various environmental water samples yielded labile fractions in the range of 1.67-55.75% against a total dissolved fraction of 44.08-69.77%. Comparison of the three chelating agents showed that H(2)sales had a weaker metal chelating strength than Chelex-100, but PVC-FSSH had comparable chelating strength to Chelex-100. PMID:19709807

Kiptoo, Jackson K; Ngila, J Catherine; Silavwe, Ned D

2009-12-30

218

Chapter 24 Protein Chromatography on Hydroxyapatite Columns  

Microsoft Academic Search

The introduction of spherical forms of hydroxyapatite has enabled protein scientists to separate and purify proteins multiple times with the same packed column. Biopharmaceutical companies have driven single column applications of complex samples to simpler samples obtained from upstream column purification steps on affinity, ion exchange or hydrophobic interaction columns. Multiple column purification permits higher protein loads to spherical forms

Larry J. Cummings; Mark A. Snyder; Kimberly Brisack

2009-01-01

219

Intelligent fuzzy supervisory control for distillation columns  

E-print Network

for dynamically adapting the models to achieve tight composition control. Simple control techniques do not exist for model adaptation in MIMO systems. This thesis will outline a fuzzy supervisory controller based on fuzzy logic and show that control performance...

Santhanam, Srinivasan

2012-06-07

220

ROBUST CONTROL OF DISTILLATION COLUMNS Sigurd Skogestad  

E-print Network

of Technology Chemical Engineering, 206-41 Pasadena, CA 91125 Abstract. Ill-conditioned plants are generally in the directions where the plant gain is low, that is, a controller similar to G,1 in di- rectionality is desirable

Skogestad, Sigurd

221

ROBUST CONTROL OF DISTILLATION COLUMNS Sigurd Skogestad  

E-print Network

of Technology Chemical Engineering, 206­41 Pasadena, CA 91125 Abstract. Ill­conditioned plants are generally \\Gamma1 in di­ rectionality is desirable. However, because of uncertainty, the direction of the large

Skogestad, Sigurd

222

Attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum cultured under varying conditions to pyrite, chalcopyrite, low-grade ore and quartz in a packed column reactor.  

PubMed

The attachment of Acidithiobacillus ferrooxidans and Leptospirillum ferriphilum spp. grown on ferrous medium or adapted to a pyrite mineral concentrate to four mineral substrata, namely, chalcopyrite and pyrite concentrates, a low-grade chalcopyrite ore (0.5 wt%) and quartzite, was investigated. The quartzite represented a typical gangue mineral and served as a control. The attachment studies were carried out in a novel particle-coated column reactor. The saturated reactor containing glass beads, which were coated with fine mineral concentrates, provided a quantifiable surface area of mineral concentrate and maintained good fluid flow. A. ferrooxidans and Leptospirillum spp. had similar attachment characteristics. Enhanced attachment efficiency occurred with bacteria grown on sulphide minerals relative to those grown on ferrous sulphate in an ore-free environment. Selective attachment to sulphide minerals relative to gangue materials occurred, with mineral adapted cultures attaching to the minerals more efficiently than ferrous grown cultures. Mineral-adapted cultures showed highest levels of attachment to pyrite (74% and 79% attachment for A. ferrooxidans and L. ferriphilum, respectively). This was followed by attachment of mineral-adapted cultures to chalcopyrite (63% and 58% for A. ferrooxidans and L. ferriphilum, respectively). A. ferrooxidans and L. ferriphilum exhibited lower levels of attachment to low-grade ore and quartz relative to the sulphide minerals. PMID:22410741

Africa, Cindy-Jade; van Hille, Robert P; Harrison, Susan T L

2013-02-01

223

Pack Saddle  

USGS Multimedia Gallery

This is a pack saddle used by Arnold Hague in the late 1800s. The wooden saddle has leather straps and a cinch used for the animal's comfort when carrying especially large loads. Pack saddles could be used to carry panniers or other large objects. Object ID: USGS-000014...

2009-07-22

224

Advanced Distillation: Programs Proposed to DOE  

E-print Network

), as well as benefiting the public. The first proposal for petroleum refineries didll't receive an award. but that work put us in all excellent position relative to a later Chemical llldustry solicitation. The proposed program is il imed at making... increases are easily achievable due to the reduced reboiler duty, and resulting substantial reduction in column internal vapor/liquid mlffic. Since 40% of refinery energy usc is for distillation, Advanced Distillation has the potential to eventually...

Woinsky, S. G.

225

Distillation tray structural parameter study: Phase 1  

NASA Technical Reports Server (NTRS)

The purpose here is to identify the structural parameters (plate thickness, liquid level, beam size, number of beams, tray diameter, etc.) that affect the structural integrity of distillation trays in distillation columns. Once the sensitivity of the trays' dynamic response to these parameters has been established, the designer will be able to use this information to prepare more accurate specifications for the construction of new trays. Information is given on both static and dynamic analysis, modal response, and tray failure details.

Winter, J. Ronald

1991-01-01

226

A Rigorous Minimum Energy Calculation Method for a Fully Thermally Coupled Distillation System  

Microsoft Academic Search

Previously, Tanskanen and Pohjola (2000) and Tanskanen and Malinen (2005) have presented a method of rigorous minimum energy calculation for non-ideal multicomponent distillation. The method is based on column simulation with a large number of equilibrium stages to mimic infinitely high columns, and it has been successfully tested with simple distillation column systems. In this paper the rigorous minimum energy

I. Malinen; J. Tanskanen

2007-01-01

227

Setting the Pressure at Which to Conduct a Distillation.  

ERIC Educational Resources Information Center

Discusses how pressure setting is determined for distillation columns, examining factors which must be considered when optimizing design for economical balance. Also discusses the basics of heat exchangers and cites a common problem with pressure differences. (JM)

Barduhn, Allen J.

1984-01-01

228

Strategies for the robust simulation of thermally coupled distillation sequences  

Microsoft Academic Search

This paper presents a novel strategy for the simulation of thermally coupled distillation sequences using process simulators. First, we show that the two side stream connections involved in a ‘thermal couple’ can be accurately substituted by a combination of a material stream and heat flow; enabling a sequence of thermally coupled distillation columns to be simulated without recycle streams, similar

Miguel A. Navarro; Juan Javaloyes; José A. Caballero; Ignacio E. Grossmann

229

Packed Lunches.  

E-print Network

and vegetables varie~ dccording to season. During certain times of the year, eggs and some meats are also scarcer and more expensive. 3 Ham and cheese sandwich Carrot and celery strips Apple Iced tea or hot coffee Brown Bag Menu Frui~ Bread- Milk Meat... butter, nut spreads and egg yol k mixtures. Pack frozen in lunch box. Set aside areas in your refrigerator, freezer an cup- boards for lunch box foods, wrappings and contai for quick lunch preparations. To avoid the morning rush, pack lunch...

Reasonover, Frances L.

1982-01-01

230

Bin Packing  

E-print Network

and is able to break symmetry completely. The proposed ... Email addresses: fdabrandao@dcc.fc.up.pt (Filipe Brand˜ao), jpp@fc.up.pt (Jo˜ao Pedro. Pedroso) ... In this section we will give account of previous approaches to bin packing and.

Filipe Brandao

2012-04-13

231

Study of the operating conditions of radial compression columns in preparative chromatography  

Microsoft Academic Search

Performance and stability were tested for radial compression columns packed with spherical particles of an octadecyl bonded silica. The performance of the radial columns remained unchanged after approximately 500 h of constant use, including a number of solvent gradient runs. The performance of analytical columns packed with the same material was comparable to that of the radial columns. The column

Matilal Sarker; Tong Yun; Georges Guiochon

1996-01-01

232

Distillation 29 Chem 355 Jasperse DISTILLATION  

E-print Network

for purifying liquids. The basic distillation process involves heating a liquid such that liquid molecules vaporize. The vapors produced are subsequently passed through a water-cooled condenser. Upon cooling

Jasperse, Craig P.

233

Logic-based methods for generating and optimizing thermally coupled distillation systems  

Microsoft Academic Search

The separation of a non-azeotropic mixture of N components in their pure components can be performed using from conventional to fully thermally coupled distillation sequences, while for conventional columns there is a one to one match between columns and separations tasks this is not true for (partially or fully) thermally coupled distillation systems where it is possible to find a

José A. Caballero; Ignacio E. Grossmann

2002-01-01

234

LRCLaboratoryColumns New York -USA  

E-print Network

to a standard system. The column body is made of a borosilicate glass tube. The columns are equipped with one torsional load on the packed bed and assures true linear compression. - True frits pressed into the plunger at the column inlet. 2. Inlet frit partially clogged. 3. Outlet frit partially clogged. 4. Separation efficiency

Lebendiker, Mario

235

Valve Packing  

NASA Technical Reports Server (NTRS)

"S Glass" yarn was originally developed by NASA for high temperature space and aeronautical applications. When John Crane, Inc. required material that would withstand temperatures higher than 1,200 degrees Fahrenheit, they contacted Owens-Corning, which had developed a number of applications for the material. John Crane combines the yarn with other components to make Style 287-I packing. The product can be used in chemical processing operations, nuclear power stations, petroleum products, etc. Advantages include increased service life and reduced maintenance costs.

1992-01-01

236

Modeling chromatographic columns  

Microsoft Academic Search

In this work a new mathematical model, based on non-equilibrium conditions, describing the dynamic adsorption of proteins in columns packed with spherical adsorbent particles is used to study the performance of chromatographic systems. Simulations of frontal chromatography, including axial dispersion, for non-equilibrium systems with non-linear adsorption isotherms are made and compared to those of the experimentally determined protein A affinity

Ahmet R Özdural; Asl? Alkan; Piet J. A. M Kerkhof

2004-01-01

237

Evaluation of New Microparticulate Packings for Aqueous Steric Exclusion Chromatography  

Microsoft Academic Search

Two types of high performance aqueous size exclusion columns have recently been developed, one a rigid spherical silica-based packing containing a new hydrophilic bonded phase (MicroPak TSK Gel Type SW) and the other an organic-based, semi-rigid gel (MicroPak TSK Gel Type PW). Characteristics of MicroPak TSK SW and PW columns were compared to other commercially available aqueous SEC columns packed

Thomas V. Alfredson; C. Timothy Wehr; Lori Tallman; Fred Klink

1982-01-01

238

Bin Packing  

E-print Network

revious weaker bounds) actually holds for randomized algorithms against oblivious adversary. On the other hand, the best known deterministic algorithm is the 1:5888competitive HARMONIC+1 by Richey [8] which groups packets by size into more than 70 categories which are then packed independently. We will see next that a few simple greedy algorithms do not perform much worse. ffl Next-Fit (NF): There is always at most one active bin. If the next packet fits into the active bin, we add it to the active bin. Otherwise, the active bin is closed (and never used again) and we put the packet into a new bin which then becomes the new active bin. ffl First-Fit (FF): As we fill the bins, we number them 1; 2; 3; : : :. The next packet is then stored in the lowest-indexed bin which still has enough free capacity (or in a new bin if all bins are to

In The Bin

239

Aggregated models for integrated distillation systems  

SciTech Connect

In this work the authors present an aggregated representation for distillation columns that can be used in the synthesis of separation sequences with heat integration. A new aggregated model is first presented for the stripping and rectifying sections of individual distillation columns. This model is based on mass balances and equilibrium feasibility, expressed in terms of flows, inlet concentrations, and recoveries. The energy balance can then be decoupled from the mass balance, and the utilities can be calculated for each separation task. The proposed model is applied to three different superstructures: state task network, state equipment network, and an intermediate representation. The proposed model yields a lower bound to the vapor flow or to the total cost of the utilities. Performance of the different superstructure representations in terms of robustness and computational time is illustrated with several examples.

Caballero, J.A. [Univ. of Alicante (Spain). Dept. of Chemical Engineering] [Univ. of Alicante (Spain). Dept. of Chemical Engineering; Grossmann, I.E. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemical Engineering] [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemical Engineering

1999-06-01

240

Contact structure for use in catalytic distillation  

DOEpatents

A method is described for conducting catalytic chemical reactions and fractionation of the reaction mixture comprising feeding reactants into a distillation column reactor, contracting said reactant in liquid phase with a fixed bed catalyst in the form of a contact catalyst structure consisting of closed porous containers containing the catalyst for the reaction and a clip means to hold and support said containers, which are disposed above, i.e., on the distillation trays in the tower. The trays have weir means to provide a liquid level on the trays to substantially cover the containers. In other words, the trays function in their ordinary manner with the addition thereto of the catalyst. The reaction mixture is concurrently fractionated in the column. 7 figs.

Jones, E.M. Jr.

1984-03-27

241

Microwave accelerated steam distillation of essential oil from lavender: A rapid, clean and environmentally friendly approach  

Microsoft Academic Search

A new process design and operation for microwave accelerated steam distillation (MASD) of essential oils was developed. A packed bed of lavender flowers (Lavandula angustifolia Mill., Lamiaceae) sits above the steam source generated by microwave heating. Only steam passes through it without the boiling water mixing with vegetable raw material, as is the case in hydro-distillation. MASD has been compared

F. Chemat; M. E. Lucchesi; J. Smadja; L. Favretto; G. Colnaghi; F. Visinoni

2006-01-01

242

Advanced Distillation Final Report  

SciTech Connect

The Advanced Distillation project was concluded on December 31, 2009. This U.S. Department of Energy (DOE) funded project was completed successfully and within budget during a timeline approved by DOE project managers, which included a one year extension to the initial ending date. The subject technology, Microchannel Process Technology (MPT) distillation, was expected to provide both capital and operating cost savings compared to conventional distillation technology. With efforts from Velocys and its project partners, MPT distillation was successfully demonstrated at a laboratory scale and its energy savings potential was calculated. While many objectives established at the beginning of the project were met, the project was only partially successful. At the conclusion, it appears that MPT distillation is not a good fit for the targeted separation of ethane and ethylene in large-scale ethylene production facilities, as greater advantages were seen for smaller scale distillations. Early in the project, work involved flowsheet analyses to discern the economic viability of ethane-ethylene MPT distillation and develop strategies for maximizing its impact on the economics of the process. This study confirmed that through modification to standard operating processes, MPT can enable net energy savings in excess of 20%. This advantage was used by ABB Lumus to determine the potential impact of MPT distillation on the ethane-ethylene market. The study indicated that a substantial market exists if the energy saving could be realized and if installed capital cost of MPT distillation was on par or less than conventional technology. Unfortunately, it was determined that the large number of MPT distillation units needed to perform ethane-ethylene separation for world-scale ethylene facilities, makes the targeted separation a poor fit for the technology in this application at the current state of manufacturing costs. Over the course of the project, distillation experiments were performed with the targeted mixture, ethane-ethylene, as well as with analogous low relative volatility systems: cyclohexane-hexane and cyclopentane-pentane. Devices and test stands were specifically designed for these efforts. Development progressed from experiments and models considering sections of a full scale device to the design, fabrication, and operation of a single-channel distillation unit with integrated heat transfer. Throughout the project, analytical and numerical models and Computational Fluid Dynamics (CFD) simulations were validated with experiments in the process of developing this platform technology. Experimental trials demonstrated steady and controllable distillation for a variety of process conditions. Values of Height-to-an-Equivalent Theoretical Plate (HETP) ranging from less than 0.5 inch to a few inches were experimentally proven, demonstrating a ten-fold performance enhancement relative to conventional distillation. This improvement, while substantial, is not sufficient for MPT distillation to displace very large scale distillation trains. Fortunately, parallel efforts in the area of business development have yielded other applications for MPT distillation, including smaller scale separations that benefit from the flowsheet flexibility offered by the technology. Talks with multiple potential partners are underway. Their outcome will also help determine the path ahead for MPT distillation.

Maddalena Fanelli; Ravi Arora; Annalee Tonkovich; Jennifer Marco; Ed Rode

2010-03-24

243

Visualization of viscous fingering in chromatographic columns  

Microsoft Academic Search

A 17 mm I.D. glass column, packed with YMC-15 (spherical C18 silica, 30 ?m particles) as the stationary phase and used with carbon tetrachloride as the mobile phase provided a suitable system for the visual observation of viscous fingering inside the packed bed, after the cylindrical lens effect had been canceled. Such a system appears nearly transparent due to the

B. Scott Broyles; R. Andrew Shalliker; Djamel E Cherrak; Georges Guiochon

1998-01-01

244

Synthesis of partially thermally coupled distillation flowsheets: Zeotropic mixtures  

Microsoft Academic Search

This article presents a detailed description of algorithms for generating the complete set of n-component zeotropic distillation flowsheets for sequences of simple two-section columns and for sequences including partially\\u000a thermally coupled complexes. The description of the algorithms is oriented toward writing of implementing computer programs.\\u000a The distillation flowsheets have been generated using their matrix representations equivalent to their graphical representations.

M. I. Skvortsova; A. V. Timoshenko; D. G. Rudakov

2011-01-01

245

Packed Bed Reactor Experiment  

NASA Video Gallery

The purpose of the Packed Bed Reactor Experiment in low gravity is to determine how a mixture of gas and liquid flows through a packed bed in reduced gravity. A packed bed consists of a metal pipe ...

246

DESIGN STUDY OF THE CONTROL OF A REACTIVE THERMALLY COUPLED DISTILLATION SEQUENCE FOR THE ESTERIFICATION OF FATTY ORGANIC ACIDS  

Microsoft Academic Search

This article reports the esterification of lauric acid and methanol studied using a thermally coupled distillation sequence with a side rectifier and the Petlyuk distillation column. The product of the esterification can be used as biodiesel. It was found that the thermally coupled distillation sequence with a side rectifier can produce ester with a high purity (around 0.999) and also

Salvador Hernández; Juan Gabriel Segovia-Hernández; Lorena Juárez-Trujillo; Juan Ernesto Estrada-Pacheco; Rafael Maya-Yescas

2010-01-01

247

Experimental and Numerical Investigation of Two Dimensional CO2 Adsorption/Desorption in Packed Sorption Beds under Non-Ideal Flows  

NASA Technical Reports Server (NTRS)

The experimental results of CO2 adsorption and desorption in a packed column indicated that the concentration wave front at the center of the packed column differs from those which are close to the wall of column filled with adsorbent material even though the ratio of column diameter to the particle size is greater than 20. The comparison of the experimental results with one dimensional model of packed column shows that in order to simulate the average breakthrough in a packed column a two dimensional (radial and axial) model of packed column is needed. In this paper the mathematical model of a non-slip flow through a packed column with 2 inches in diameter and 18 inches in length filled with 5A zeolite pellets is presented. The comparison of experimental results of CO2 absorption and desorption for the mixed and central breakthrough of the packed column with numerical results is also presented.

Mohamadinejad, H.; Knox, J. C.; Smith, J. E.; Croomes, Scott (Technical Monitor)

2001-01-01

248

A critical review of dispersion in packed beds  

NASA Astrophysics Data System (ADS)

The phenomenon of dispersion (transverse and longitudinal) in packed beds is summarized and reviewed for a great deal of information from the literature. Dispersion plays an important part, for example, in contaminant transport in ground water flows, in miscible displacement of oil and gas and in reactant and product transport in packed bed reactors. There are several variables that must be considered, in the analysis of dispersion in packed beds, like the length of the packed column, viscosity and density of the fluid, ratio of column diameter to particle diameter, ratio of column length to particle diameter, particle size distribution, particle shape, effect of fluid velocity and effect of temperature (or Schmidt number). Empirical correlations are presented for the prediction of the dispersion coefficients ( D T and D L) over the entire range of practical values of Sc and Pem, and works on transverse and longitudinal dispersion of non-Newtonian fluids in packed beds are also considered.

Delgado, J. M. P. Q.

2006-02-01

249

Chitosan modified ordered mesoporous silica as micro-column packing materials for on-line flow injection-inductively coupled plasma optical emission spectrometry determination of trace heavy metals in environmental water samples  

Microsoft Academic Search

A novel adsorbent of chitosan chemically modified ordered mesoporous silica was synthesized and employed as a solid phase extraction (SPE) material for flow injection (FI) micro-column preconcentration on-line coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) determination of trace heavy metals V, Cu, Pb, Cd and Hg in environmental water samples. The factors affecting separation and preconcentration of target

Dahui Chen; Bin Hu; Chaozhang Huang

2009-01-01

250

APPLICATION OF CAPILLARY SUPERCRITICAL FLUID CHROMATOGRAPHY TO THE ANALYSIS OF A MIDDLE DISTILLATE FUEL  

EPA Science Inventory

The paper describes the application of capillary supercritical fluid chromatography (SFC) to the analysis of a middle distillate fuel. Small diameter (50 micrometer i.d.) fused silica capillary columns coated with crosslinked 50% phenyl polymethylsiloxane provided high separation...

251

Identification of petroleum distillates from fire debris using multidimensional gas chromatography  

Microsoft Academic Search

A method for identifying petroleum distillates (accelerants) in fire debris samples by dynamic headspace analysis and multidimensional gas chromatography is described. The method relies on the separation of target compounds characteristic of different petroleum distillate classes from interfering co-eluting and matrix components. A relatively nonpolar column is used to characterize the volatility distribution of the sample and heartcutting to a

A. Jayatilaka; C. F. Poole

1994-01-01

252

Dynamic Behaviour of Thermally Coupled Distillation Arrangements: Effect of the Interconnection Flowrate  

Microsoft Academic Search

Thermally coupled distillation sequences can provide significant energy savings with respect to the operation of conventional distillation columns. Coupled sequences exhibit a complex struc- ture, with recycle streams, that appear to affect their controllability properties. One potential solution to this problem has been suggested through the operation of complex schemes under con- ditions that do not provide minimum energy consumption.

Erick Yair Miranda-Galindo; Juan Gabriel Segovia-Hernández

2008-01-01

253

Logic based algorithms for the rigorous design of thermally coupled distillation sequences  

Microsoft Academic Search

This paper presents an algorithm for the rigorous design of thermally coupled distillation sequences using process simulators. First we show that the two side streams connections that produce a thermal ‘couple’ can be substituted by a combination of a material stream and a heat flow. In this way, the sequence of thermally coupled distillation columns can be simulated without recycle

José A. Caballero; Ignacio E. Grossmann

2007-01-01

254

Reactive Distillation and Air Stripping Processes for Water Recycling and Trace Contaminant Control  

NASA Technical Reports Server (NTRS)

Reactive distillation designs are considered to reduce the presence of volatile organic compounds in the purified water. Reactive distillation integrates a reactor with a distillation column. A review of the literature in this field has revealed a variety of functional reactive columns in industry. Wastewater may be purified by a combination of a reactor and a distiller (e.g., the EWRS or VPCAR concepts) or, in principle, through a design which integrates the reactor with the distiller. A review of the literature in reactive distillation has identified some different designs in such combinations of reactor and distiller. An evaluation of reactive distillation and reactive air stripping is presented with regards to the reduction of volatile organic compounds in the contaminated water and air. Among the methods presented, an architecture is presented for the evaluation of the simultaneous oxidation of organics in air and water. These and other designs are presented in light of potential improvements in power consumptions and air and water purities for architectures which include catalytic activity integrated into the water processor. In particular, catalytic oxidation of organics may be useful as a tool to remove contaminants that more traditional distillation and/or air stripping columns may not remove. A review of the current leading edge at the commercial level and at the research frontier in catalytically active materials is presented. Themes and directions from the engineering developments in catalyst design are presented conceptually in light of developments in the nanoscale chemistry of a variety of catalyst materials.

Boul, Peter J.; Lange, Kevin E.; Conger, Bruce; Anderson, Molly

2009-01-01

255

Low Energy Distillation Schemes  

E-print Network

of reducing energy consumption. We look at how the better integrated distillation schemes can be quickly identified. It is found that the design of integrated schemes is quicker than that of non-integrated schemes. We then look at how the use of heat pumps...

Polley, G. T.

256

Tritium Attenuation by Distillation  

SciTech Connect

The objective of this study was to determine how a 100 Area distillation system could be used to reduce to a satisfactory low value the tritium content of the dilute moderator produced in the 100 Area stills, and whether such a tritium attenuator would have sufficient capacity to process all this material before it is sent to the 400 Area for reprocessing.

Wittman, N.E.

2001-07-31

257

Distillation under electric fields  

SciTech Connect

Distillation Is the most common separation process used in the chemical and petroleum industry. Major limitations in the applicability and efficiency of distillation come from thermodynamic equilibria, that is, vapor-liquid equilibria (VLE), and heat and mass transfer rates. In this work, electric fields are used to manipulate the VLE of mixtures. VLE experiments are performed for various binary mixtures in the presence of electric fields on the order of a few kilovolts per centimeter. The results show that the VLE is changed by electric fields, with changes in the separation factor as high as 10% being observed. Batch distillation experiments are also carried out for binary mixtures of 2-propanol and water with and without an applied electric field. Results show enhanced distillation rates and separation efficiency in the presence of an electric field but decreased separation enhancement when the electric current is increased. The latter phenomenon is caused by the formation at the surface of the liquid mixture of microdroplets that are entrained by the vapor. These observations suggest that there should be an electric field strength for each system for which the separation enhancement is maximum.

Shah, V.M. [Univ. of Tennessee, Knoxville, TN (United States). Chemical Engineering Dept.; Blankenship, K.D.; Tsouris, C. [Oak Ridge National Lab., TN (United States)

1997-11-01

258

Design and synthesis of multicomponent thermally coupled distillation flowsheets  

Microsoft Academic Search

The design and synthesis of thermally coupled distillation flowsheets for separations of five-component mixtures are studied. Four types of possible configurations are identified when simple and complex columns are both considered in a flowsheet. A universal design procedure is developed for design of any types of the identified configurations based on the abstraction of the three basic units in the

Ben-Guang Rong; Andrzej Kraslawski; Lars Nyström

2001-01-01

259

Trajan's Column  

NSDL National Science Digital Library

This Website, from McMaster University, uses the combined skills of artists, writers, programmers, and Web designers to create a resource for the study of Trajan's column, a Roman architectural monument. This 100-foot marble column, built during the reign of Emperor Trajan, 98-117 AD, is topped with a gilded statue of Trajan and decorated with carvings recounting Trajan's rule, primarily the Dacian Wars and his building projects. The heart of the Website is the database of 500 slides of the carvings; indexes allow users to view the slides in thematic groupings such as images of sides of the column, groups organized by subject keywords, or carvings made with specific tools. Cartoons or drawings of the column help to contextualize the details found in the slides, and essays provide more information on its design, construction, and preservation.

260

Approximate strip packing  

SciTech Connect

We present an approximation scheme for strip-packing, or packing rectangles into a rectangle of fixed width and minimum height, a classical NP-hard cutting-stock problem. The algorithm finds a packing of n rectangles whose total height is within a factor of (1 + {epsilon}) of optimal, and has running time polynomial both in n and in 1/{epsilon}. It is based on a reduction to fractional bin-packing, and can be performed by 5 stages of guillotine cuts.

Kenyon, C. [CNRS, Lyon (France); Remila, E. [LASPI, Roanne (France)

1996-12-31

261

On Discrete Hyperbox Packing  

E-print Network

Bin packing is a very important and popular research area in the computer science field. Past work showed many good and real-world packing algorithms. How- ever, due to the complexity of the problem in multiple-dimensional bin packing, also called...

Li, Xiafeng

2010-01-14

262

Study of longitudinal mixing in pulse columns 0. 057-1. 5 m in diameter with distributed packings in the case of low-velocity solution and pulp flows  

SciTech Connect

The authors present results on the hydraulics of one- and two-phase flows for counterflow pulse columns in regard to the conditions found in hydrometallurgy and leaching operations. They contend that the efficiency of such units can be calculated and hence optimized if the longitudinal mixing coefficients are available; to this end; they determine these coefficients mathematically as well as from curves obtained from the response of the system to the pulsed introduction of the following indicators: a solution of methylene blue, sodium chloride, chloroauric acid labeled with gold 198 and sodium iodide labeled with the iodine 131 isotope, and a solid phase irradiated in the reactor with neutrons with induction of the iron 55 isotope.

Zakharov, E.I.; Roshchin, D.V.; Levchenko, A.L.; Kobzev, V.V.; Shabanov, A.I.; Kiselev, V.N.

1986-09-20

263

Liquid Chromatographic Preparative Packing Utility as a Function of Particle Shape  

Microsoft Academic Search

The “equal-cut-point” approach (12) has been applied to comparing the relative utilities for preparative liquid chromatography of five irregular and three spherical packings. Packed with these, the variation of peak width with loading was first established and plotted, for columns of given length. From these plots, the loading that produced a given peak width was found for each column. The

John A. Perry; Ted J. Szczerba

1993-01-01

264

Method for making a non-extractable stationary phase of polymer within a capillary column  

DOEpatents

A method for coating interior capillary column surfaces, or packing material of a packed column, used for gas chromatography, with a stationary polymer phase that is cross-linked by exposing it to a low-temperature plasma that is uniformly distributed over the column or packing material for a predetermined period of time to effect the desired degree of cross-linking of the coating.

Springston, Stephen R. (Middle Island, NY)

1990-01-01

265

Study of the operating conditions of axial compression columns for preparative chromatography  

Microsoft Academic Search

The packing behavior and the stability of a spherical-particle, silica-based packing material and the operation of an axial compression column are discussed. The coupling between the axial compression pressure and the inlet pressure at constant flow-rate was investigated. The results demonstrated also an excellent column efficiency, a rapid packing consolidation, and a long-term stability of the column performance. Reduced height

Matilal Sarker; Georges Guiochon

1995-01-01

266

Modelling liquid redistribution in a packed bed  

NASA Astrophysics Data System (ADS)

The paper is devoted to the computational fluid dynamics (CFD) simulation of liquid spreading process in a packed bed. The volume of fluid (VOF) approach was applied to simulate the flow in a realistic porous region composed of 6mm Raschig rings. Modelling results were used to determine the probability density function (PDF) distribution of liquid velocity vector orientation angle which was then implemented into 2-fluid Euler-Euler multiphase model of packing column. The simulation showed that the model is capable to simulate adequately the liquid redistribution in a porous region being, however, much more efficient computationally than the VOF method.

Niegodajew, Pawe?; Asendrych, Dariusz; Marek, Maciej; Drobniak, Stanis?aw

2014-08-01

267

Hydrodynamic chromatography of macromolecules on 2 ?m non-porous spherical silica gel packings  

Microsoft Academic Search

Non-porous spherical 2?m silica gel particles have been tested as packing for hydrodynamic chromatography of macromolecules (HDC). Columns packed with these particles in 250×4.6mm i.d. columns can be operated very efficiently (e.g. a reduced plate height of about 2) when the detection cell is miniaturized. The packing is suitable for the separation of polystyrenes of Mw of 104–107 by hydrodynamic

J. C. Kraak; R. Oostervink; H. Poppe; U. Esser; K. K. Unger

1989-01-01

268

Simulation, design, and analysis of azeotropic distillation operations  

SciTech Connect

The computational tools needed for simulation, design, and analysis of azeotropic distillation operations are described. These tools include simple methods to identify the existence of binary and ternary azeotropes and to classify ternary mixtures as homogeneous or heterogeneous. The tools also include more complex methods to compute the phase diagram (or a heterogeneous liquid boiling surface), predict liquid-vapor phase equilibrium, and/or predict liquid-liquid-vapor phase equilibrium for simulations of batch and continuous distillation column operations. Important new features of these tools are the incorporation of a fast and efficient method for test of phase stability in simulation of distillation operations, the ability to handle a large range of mixtures (including mixtures with supercritical compounds), and the ability for computations covering wide ranges of temperature and pressure. On the basis of these tools, simple and consistent design algorithms are developed. The applicability of the design algorithms is verified through process simulation and analysis of the predicted behavior and data from the open literature. Conditions are given for examples illustrating (when and how possible distillation boundaries can be crossed) how multiple steady states can be obtained. Finally, the effect of changes in operating on the dynamic behavior of the azeotropic distillation columns and the sensitivity of design to the prediction of phase equilibria are presented.

Bossen, B.S.; Joergensen, S.B.; Gani, R. (Technical Univ. of Denmark, Lyngby (Denmark))

1993-04-01

269

Dynamic NMR microscopy of chromatographic columns  

Microsoft Academic Search

Pulsed magnetic field gradients encoded a discrete spatial and temporal motion of the molecules of a fluid percolating through the packed bed of a dynamic radial compression column for liquid chromatography. Two packing materials of porous, chemically bonded C18 silica were used; large irregularly shaped particles (55--105 μm) and small spherical particles (6 μm). By combining pulsed field gradient NMR

Ulrich Tallarek; Ernst Bayer; Dagmar Van Dusschoten; T. W. J. Scheenen; Henk Van As; Georges Guiochon; Uwe D. Neue

1998-01-01

270

Chitosan modified ordered mesoporous silica as micro-column packing materials for on-line flow injection-inductively coupled plasma optical emission spectrometry determination of trace heavy metals in environmental water samples.  

PubMed

A novel adsorbent of chitosan chemically modified ordered mesoporous silica was synthesized and employed as a solid phase extraction (SPE) material for flow injection (FI) micro-column preconcentration on-line coupled with inductively coupled plasma optical emission spectrometry (ICP-OES) determination of trace heavy metals V, Cu, Pb, Cd and Hg in environmental water samples. The factors affecting separation and preconcentration of target heavy metals such as pH, sample flow rate and volume, eluent concentration and volume, interfering ions were investigated. Under the optimized experimental conditions, an enrichment factor of 20 and sampling frequency of 10h(-1) were obtained. The detection limits of the method for V, Cu, Pb, Cd and Hg were 0.33, 0.30, 0.96, 0.05 and 0.93 ng mL(-1), and the relative standard deviations (RSDs) were 2.8%, 6.7%, 1.8%, 4.0% and 5.3% (n=7, C=10 ng mL(-1)), respectively. The adsorption capacities of chitosan modified ordered mesoporous silica for V, Cu, Pb, Cd, and Hg were found to be 16.3, 21.7, 22.9, 12.2 and 13.5 mg g(-1), respectively. In order to validate the developed method, a certified reference material of GSBZ50009-88 environmental water sample was analyzed and the determined values were in good agreement with the certified values. The proposed method has also been applied to the determination of trace heavy metals in natural water samples with satisfactory results. PMID:19203614

Chen, Dahui; Hu, Bin; Huang, Chaozhang

2009-04-30

271

Column Chromatography  

NSDL National Science Digital Library

In this activity, learners separate the components of Gatorade using a home-made affinity column. In doing so, learners model the basic principle of affinity chromatography, a technique used to purify chemicals as well as bio-pharmaceuticals and petroleum products. This resource contains information about affinity chromatography and polarity.

Yu, Julie

2007-01-01

272

An Analogy between Fractional Distillation and Separating Physically Fit and Physically Less Fit Persons  

NASA Astrophysics Data System (ADS)

Separating two liquids in a fractional distillation column on the basis of their difference in boiling points is analogous to separating a group of people on the basis of their physical fitness by making them climb a flight of stairs. Several aspects of this unit operation such as column height, flooding, and reflux ratio are explained with the help of this analogy.

Mukesh, Doble

2001-02-01

273

Leaf Pack Network  

NSDL National Science Digital Library

The Leaf Pack Network (LPN) is a network of teachers and students investigating their local stream ecosystems by participating in the leaf pack experiment, which involves creating an artificial leaf pack (dry leaves in a mesh bag), immersing it in a stream for 3-4 weeks, and examining it for signs of aquatic insects as indicators of stream health. Participating classrooms share their data through the internet. This activity highlights the connection between streamside forests and the ecology of rivers and streams.

274

Distillation: The Efficient Workhorse  

E-print Network

the relation for minimum reflux Q ? A [1 +( (a-l)xll (5 ) a-I where A is the heat, of vaporization and a is the relative volatility of the components; and if, we further eliminate 6T's in the reboiler and condenser and 6P in the column, then Maximum [1 1... losses are in ? pressure drop and temperature difference. This is a characteristic of towers with low relative volatilities. ***In this tower the losses are unusually high because the column operated between two refrigeration levels which were fixed...

Steinmeyer, D.

275

Systems and methods for reactive distillation with recirculation of light components  

DOEpatents

Systems and methods for producing gas-to-liquids products using reactive distillation are provided. The method for producing gas-to-liquids products can include reacting a feedstock in a column having a distillation zone and a reaction zone to provide a bottoms stream and an overhead stream. A first portion of the overhead stream can be recycled to the column at the top of the reaction zone and second portion of the overhead stream can be recycled to the column at the bottom of the reaction zone.

Stickney, Michael J. (Nassau Bay, TX); Jones, Jr., Edward M. (Friendswood, TX)

2011-07-26

276

Optimization approach to entanglement distillation  

E-print Network

We put forward a method for optimized distillation of partly entangled pairs of qubits into a smaller number of more entangled pairs by recurrent local unitary operations and projections. Optimized distillation is achieved by minimization of a cost function with up to 30 real parameters, which is chosen to be sensitive to the fidelity and the projection probability at each step. We show that in many cases this approach can significantly improve the distillation efficiency in comparison to the present methods.

T. Opatrny; G. Kurizki

1998-11-30

277

Qutrit magic state distillation  

NASA Astrophysics Data System (ADS)

Magic state distillation (MSD) is a purification protocol that plays an important role in fault-tolerant quantum computation. Repeated iteration of the steps of an MSD protocol generates pure single non-stabilizer states, or magic states, from multiple copies of a mixed resource state using stabilizer operations only. Thus mixed resource states promote the stabilizer operations to full universality. MSD was introduced for qubit-based quantum computation, but little has been known concerning MSD in higher-dimensional qudit-based computation. Here, we describe a general approach for studying MSD in higher dimensions. We use it to investigate the features of a qutrit MSD protocol based on the five-qutrit stabilizer code. We show that this protocol distils non-stabilizer magic states, and identify two types of states that are attractors of this iteration map. Finally, we show how these states may be converted, via stabilizer circuits alone, into a state suitable for state-injected implementation of a non-Clifford phase gate, enabling non-Clifford unitary computation.

Anwar, Hussain; Campbell, Earl T.; Browne, Dan E.

2012-06-01

278

Flat Pack Toy Design  

ERIC Educational Resources Information Center

In this article, the author introduces the concept of flat pack toys. Flat pack toys are designed using a template on a single sheet of letter-sized card stock paper. Before being cut out and built into a three-dimensional toy, they are scanned into the computer and uploaded to a website. With the template accessible from the website, anyone with…

Hutcheson, Brian

2007-01-01

279

Nasal packing after septoplasty.  

PubMed

A prospective study to compare 3 different types of nasal pack after septoplasty with or without a supplementary turbinectomy has been performed with respect to discomfort and complications caused by the packing and the short-term results evaluated 3 months after operation. Fingerstall packings gave less problems than either Merocel or hydrocortisone-terramycine gauze packs with ventilation tubes. They were easier to remove and were associated with less persistent secretion in the post-operative period. No definite advantage from the patient's point of view has been demonstrated by the use of tubes and nasal packing. An analysis of the nasal patency 3 months post-operatively by peak-flow index and acoustic rhinometry revealed no differences between groups. PMID:1587033

Illum, P; Grymer, L; Hilberg, O

1992-04-01

280

Enzyme activity maintenance in packed-bed reactors via continuous enzyme addition  

Microsoft Academic Search

An operational scheme for using immobilized enzymes in packed-bed reactors that permits operation at a constant throughput rate and constant product quality is described. The scheme uses columns operated in series with continuous enzyme volume in the column system. Operation of columns in series is compared to operation where the flow rate is decreased to compensate for a loss of

F. H. Verhoff; S. T. Schlager

1981-01-01

281

ESTUDIO DE SISTEMAS DE DESTILACIÓN TÉRMICAMENTE ACOPLADOS CON REACCIÓN QUÍMICA STUDY OF THERMALLY COUPLED DISTILLATION SYSTEMS WITH CHEMICAL REACTION  

Microsoft Academic Search

Thermally coupled distillation systems have been excellent options to save energy and capital investment for the separation of multicomponent mixtures. Latest information about design, operation and control of these systems has been published and it has allowed a practical implementation in the chemical industry. In this paper the ethyl acetate process is studied, using distillation systems with side columns (either

F. O. Barroso-Muñoz; S. Hernández; J. G. Segovia-Hernández; A. F. Aguilera-Alvarado

2006-01-01

282

Distilling entanglement from Fermions  

E-print Network

Since Fermions are based on anti-commutation relations, their entanglement can not be studied in the usual way, such that the available theory has to be modified appropriately. Recent publications consider in particular the structure of separable and of maximally entangled states. In this talk we want to discuss local operations and entanglement distillation from bipartite, Fermionic systems. To this end we apply an algebraic point of view where algebras of local observables, rather than tensor product Hilbert spaces play the central role. We apply our scheme in particular to Fermionic Gaussian states where the whole discussion can be reduced to properties of the covariance matrix. Finally the results are demonstrated with free Fermions on an infinite, one-dimensional lattice.

M. Keyl

2008-12-03

283

Contexts for Column Addition and Subtraction  

ERIC Educational Resources Information Center

In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by designing…

Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen

2011-01-01

284

21 CFR 184.1848 - Starter distillate.  

Code of Federal Regulations, 2012 CFR

...a) Starter distillate (butter starter distillate) is a steam distillate of the culture of any or all of the following species of bacteria grown on a medium consisting of skim milk usually fortified with about 0.1 percent citric...

2012-04-01

285

21 CFR 184.1848 - Starter distillate.  

...a) Starter distillate (butter starter distillate) is a steam distillate of the culture of any or all of the following species of bacteria grown on a medium consisting of skim milk usually fortified with about 0.1 percent citric...

2014-04-01

286

21 CFR 184.1848 - Starter distillate.  

Code of Federal Regulations, 2013 CFR

...a) Starter distillate (butter starter distillate) is a steam distillate of the culture of any or all of the following species of bacteria grown on a medium consisting of skim milk usually fortified with about 0.1 percent citric...

2013-04-01

287

21 CFR 184.1848 - Starter distillate.  

Code of Federal Regulations, 2011 CFR

...a) Starter distillate (butter starter distillate) is a steam distillate of the culture of any or all of the following species of bacteria grown on a medium consisting of skim milk usually fortified with about 0.1 percent citric...

2011-04-01

288

Upflow column reactor design for dechlorination of chlorinated pulping wastes by Penicillium camemberti  

E-print Network

of chlorinated organics. A continuous upflow packed bed reactor was designed and operated successfully in our freely suspended ones in further exploitation of the process. An upflow glass wool packed column reactorUpflow column reactor design for dechlorination of chlorinated pulping wastes by Penicillium

Taseli, Hasan

289

Aroma Recovery in Wine Dealcoholization by SCC Distillation  

Microsoft Academic Search

The aroma recovery in wine dealcoholization by spinning cone column (SCC) distillation technique has been studied, with the\\u000a analysis of the influence of the process factors: raw wine flow rate and aromatic extraction percentage. This aroma recovery\\u000a has been measured in terms of aromatic richness (number of peaks obtained in the chromatogram) and aromatic intensity (total\\u000a peaks area of the

Yulissa Y. Belisario-Sánchez; Amaury Taboada-Rodríguez; Fulgencio Marín-Iniesta; Asunción Iguaz-Gainza; Antonio López-Gómez

290

Graphitic packing removal tool  

SciTech Connect

Graphitic packing removal tools are described for removal of the seal rings in one piece from valves and pumps. The packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal.

Meyers, K.E.; Kolsun, G.J.

1996-12-31

291

DESIGN SCALE-UP SUITABILITY FOR AIR-STRIPPING COLUMNS  

EPA Science Inventory

Air-stripping in a packed column is sometimes used to remove volatile organic compounds from contaminated water supplies. Since the design engineer frequently uses data from a pilot air-stripping column to design a full-scale system, the suitability of such design scale-up was in...

292

Non-planar microfabricated gas chromatography column  

DOEpatents

A non-planar microfabricated gas chromatography column comprises a planar substrate having a plurality of through holes, a top lid and a bottom lid bonded to opposite surfaces of the planar substrate, and inlet and outlet ports for injection of a sample gas and elution of separated analytes. A plurality of such planar substrates can be aligned and stacked to provide a longer column length having a small footprint. Furthermore, two or more separate channels can enable multi-channel or multi-dimensional gas chromatography. The through holes preferably have a circular cross section and can be coated with a stationary phase material or packed with a porous packing material. Importantly, uniform stationary phase coatings can be obtained and band broadening can be minimized with the circular channels. A heating or cooling element can be disposed on at least one of the lids to enable temperature programming of the column.

Lewis, Patrick R. (Albuquerque, NM); Wheeler, David R. (Albuquerque, NM)

2007-09-25

293

Tiber winding pack design  

SciTech Connect

A preliminary winding pack design was performed with the goal of showing feasibility of producing 10-T maximum field with a pack current density of 40 A.mm/sup -2/ while accepting 2.7 kW per coil nuclear heating. A cable-in-conduit conductor design (CIC), reported at the 6th Topical Meeting on the Technology of Fusion Energy, was based on several key issues.

Miller, J.R.

1985-08-19

294

ColumnBased Strip Packing using Ordered and Compliant Containment  

E-print Network

of Miami. Email: daniels@das.harvard.edu. This research was funded by the Textile/Clothing Technology@cs.miami.edu. This research was funded by the Textile/Clothing Technology Corporation from funds awarded to them by the Alfred P. Sloan Foundation, by NSF grant CCR­91­ 157993, and by a subcontract of a National Textile Center

Daniels, Karen M.

295

Optimal Control of Distillation Systems  

E-print Network

The optimum performance of a distillation system can be evaluated by examining the product purities, the product recoveries, and the system's capability to respond to small or large, expected or unexpected, plant disturbances. An optimal control...

Chatterjee, N.; Suchdeo, S. R.

1984-01-01

296

Energy-saving distillation in fuel ethanol production: steady-state and dynamic analysis  

SciTech Connect

This work is a thorough study of distillation designs and operating conditions to produce a fuel-grade ethanol product from a typical grain fermentation broth. Two characteristic features of this system are the dilute feed concentration and the highly non-ideal vapor-liquid equilibrium. A feed concentration of 2.9 mol%, a plant size of 20 million gallons per year of ethanol product and a minimum of 15% return on incremental investments (after tax) are used throughout the study. For production of 83 mole% product, a design featuring mechanical vapor recompression for both distillation and evaporation has the lowest operating cost ($0.135/gallon of ethanol product). The same evaporator with a multi-column distillation design (split-feed flow pattern) and integration of a standard distillation column with a multi-effect evaporator have slightly higher costs ($0.15 and $0.16, respectively). The costs given reflect the operating cost (including depreciation, maintenance, etc.) for both the distillation and evaporation sections of the plant. Comparative costs are very sensitive to the costs used for utilities (steam cost is $5.00/1000 lbs.; electricity cost is $0.07/KWH). Other design variables, such as feed temperature, feed concentration and production rate effect significant changes in costs per gallon, but do not change the order of preference of design configurations. For the production of higher purity distillates without the use of azeotropic or extractive distillation techniques, several vacuum distillation designs are considered. The change in costs with distillate concentration is very significant above 85 mole%. The vapor recompression design and a multi-effect distillation with heavy-split are the best candidates for a 90 mole% product.

Collura, M.A.

1985-01-01

297

Monolithic silica columns for high-efficiency chromatographic separations  

Microsoft Academic Search

Studies on the structural and chromatographic properties of monolithic silica columns were reviewed. Monolithic silica columns prepared from tetraalkoxysilane by a sol–gel method showed high efficiency and high permeability on the basis of the small-sized silica skeletons, large-sized through-pores, and resulting through-pore size\\/skeleton size ratios much larger than those found in a particle-packed column.

Nobuo Tanaka; Hiroshi Kobayashi; Norio Ishizuka; Hiroyoshi Minakuchi; Kazuki Nakanishi; Ken Hosoya; Tohru Ikegami

2002-01-01

298

Radiotracer Imaging of Sediment Columns  

NASA Astrophysics Data System (ADS)

Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, E? = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) ? Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (<1 day). This allows multiple measurements to be made on the same column and thus the sediment biology to be monitored non-invasively over time (i.e. after an augmentation has been introduced) and minimizes long-lived radioactive waste. Different parameters can be measured, depending on the tracer type and delivery. A constant infusion of a conservative tracer, such as the positron emitter Br-76 (T1/2= 16.2 hr), measures the exclusion fraction (as a function of position in the column), while a bolus maps the flow velocity as a function of position. A tracer that interacts chemically with the contents of the column (e.g., [99m-Tc(VII)O4]- reduced to 99m-TcO2 by Fe(II) ) yields a map of the chemical environment (e.g., the distribution of Fe(II)). Image of Tc-99m distribution in a column containing Rifle sediment at four times.

Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.

2010-12-01

299

Distillation and Air Stripping Designs for the Lunar Surface  

NASA Technical Reports Server (NTRS)

Air stripping and distillation are two different gravity-based methods, which may be applied to the purification of wastewater on the lunar base. These gravity-based solutions to water processing are robust physical separation techniques, which may be advantageous to many other techniques for their simplicity in design and operation. The two techniques can be used in conjunction with each other to obtain high purity water. The components and feed compositions for modeling waste water streams are presented in conjunction with the Aspen property system for traditional stage distillation models and air stripping models. While the individual components for each of the waste streams will vary naturally within certain bounds, an analog model for waste water processing is suggested based on typical concentration ranges for these components. Target purity levels for the for recycled water are determined for each individual component based on NASA s required maximum contaminant levels for potable water Distillation processes are modeled separately and in tandem with air stripping to demonstrate the potential effectiveness and utility of these methods in recycling wastewater on the Moon. Optimum parameters such as reflux ratio, feed stage location, and processing rates are determined with respect to the power consumption of the process. Multistage distillation is evaluated for components in wastewater to determine the minimum number of stages necessary for each of 65 components in humidity condensate and urine wastewater mixed streams. Components of the wastewater streams are ranked by Henry s Law Constant and the suitability of air stripping in the purification of wastewater in terms of component removal is evaluated. Scaling factors for distillation and air stripping columns are presented to account for the difference in the lunar gravitation environment. Commercially available distillation and air stripping units which are considered suitable for Exploration Life Support are presented. The advantages to the various designs are summarized with respect to water purity levels, power consumption, and processing rates.

Boul, Peter J.; Lange, Kevin E.; Conger, Bruce; Anderson, Molly

2009-01-01

300

Biodegradation of chlorinated aliphatic hydrocarbon mixtures in a single-pass packed-bed reactor  

Microsoft Academic Search

Aliphatic chlorinated compounds, such as trichloroethylene (TCE) and tetrachloroethylene (PCE), are major contaminants of\\u000a ground water. A single-pass packed-bed bioreactor was utilized to study the biodegradation of organic waste mixtures consisting\\u000a of PCE, TCE, and other short-chain chlorinated organics. The bioreactor consisted of two 1960-mL glass columns joined in a\\u000a series. One column was packed with sand containing a microbial

L. W. Lackey; T. J. Phelps; P. R. Bienkowski; D. C. White

1993-01-01

301

Preparation and characterization of spherical polymer packings from polybutadiene for size-exclusion chromatography  

Microsoft Academic Search

Porous polymer spherical particles for column packings in nonaqueous size-exclusion chromatography (SEC) were prepared from 1,2-syndiotactic polybutadiene by suspension and evaporation method. The polymer microbeads obtained were crosslinked by radical reaction between 2-vinyl groups in polybutadiene with ultraviolet radiation, to render them insoluble. These microbeads have wider chromatographic separation width than polystyrene column packings. In addition, the polybutadiene microbeads did

S. Nagaoka; T. Satoh; K. Sakamoto; H. Ihara

2005-01-01

302

Porous polymer packings from vinyl ether derivatives for reversed-phase liquid chromatography  

Microsoft Academic Search

Spherical, porous-polymer particles for column packing in high-performance liquid chromatography were prepared by suspension copolymerization of alkylvinyl ether with triethyleneglycol divinyl ether. The hydrophobicity of the packings was easily adjusted by changing the monomer ratio. The packings showed the usual reversed-phase liquid chromatographic properties, but did not sho abnormal retention, tailing and broadening of peaks and irreversible adsorption of ionic

C. Hirayama; H. Ihara; S. Nagaoka; H. Makise

1992-01-01

303

Oxygen transfer in ferric iron biological production in a packed-bed reactor  

Microsoft Academic Search

In this paper, oxygen transfer in the ferrous iron biooxidation process in a packed-bed reactor is studied. The reactor consists of a polymethyl methacrylate column randomly packed with siliceous stone particles with inlets for liquid medium and air at the bottom from where they flood the reactor. The aim of this work is to determine the parameters that influence the

A Mazuelos; R Romero; I Palencia; F Carranza; F. J Borjas

2002-01-01

304

Colloidal aspects and packing behaviour of charged microparticulates in high efficiency ion chromatography.  

PubMed

The development of small particles in ion chromatography (IC) is a recent phenomenon. Very few studies are available on packing polymeric particles bearing ionizable functional groups. This study explores the colloidal and rheological properties that govern slurry packing to form high efficiency IC columns. The polymeric substrate used was non-porous 4.4 ?m sulfonated ethylvinylbenzene–divinylbenzene (1.4 mequiv. SO(3)H/g resin) with 55% crosslink. We developed simple tests optical microscopy and sedimentation tests for predicting the quality of packed columns. The negatively charged particles (zeta potential: ?52 mV in water) behave like colloids. The influence of counter-ion charge (Al(3+), Mg(2+), Na(+)) and ionic strength on column efficiency followed the Schulze–Hardy rule. Highly flocculating slurries give poorly packed columns with N ~ 900 whereas under non-agglomerating slurry conditions efficiencies up to N > 10,000 can be achieved. A non-agglomerating slurry also shows non-Newtonian behaviour, specifically shear thickening. Packing at lower flow rate (<1 mL/min) or higher temperature (>50 °C) reduces the shear thickening and produces higher efficiency columns. The packed sulfonated resin column is coated with 72 nm quaternary ammonium bearing latex (AS4A) and used in the separation of F(?), Cl(?), NO(2)(?), Br(?), and NO(3)(?) yielding a reduced plate height of 1.9 under optimum conditions. PMID:23218187

Wahab, M Farooq; Pohl, Christopher A; Lucy, Charles A

2012-12-28

305

DNA Spin Columns Regular Spin Columns  

E-print Network

or bubbles. 1. Remove tip of Bio-Rad column. Place column in 13 X 100 mm glass tube in rack. Fill column centrifuge with swing-out rotor. Plastic Syringes Prepare syringes as follows. Cut circles of GF/C (glass

Aris, John P.

306

Professional Training Information Pack  

E-print Network

Intending Professional Training Students Year 2 Information Pack #12;- 1 - Applying for a Professional Training Placement To be allowed to do the Professional Training you must have enrolled on one must talk to Dr J. M. Thompson immediately. General introduction to professional training Students

Davies, Christopher

307

Continuous synthesis of lauroyl or oleoyl erythritol by a packed-bed reactor with an immobilized lipase  

Microsoft Academic Search

A system is proposed for the continuous synthesis of an acyl erythritol through the immobilised-lipase-catalysed condensation of the corresponding fatty acid and erythritol in acetone. A fatty acid dissolved in acetone was fed to a column packed with erythritol powders, and erythritol was dissolved in the column at a saturated concentration. The effluent from the column was introduced to a

Junkui Piao; Takashi Kobayashi; Shuji Adachi; Kazuhiro Nakanishi; Ryuichi Matsuno

2004-01-01

308

Consideration of grain packing in granular iron treatability studies.  

PubMed

Commercial granular iron (GI) is light steel that is used in Permeable Reactive Barriers (PRBs). Investigations into the reactivity of GI have focused on its chemical nature and relatively little direct work has been done to account for the effects of grain shape and packing. Both of these factors are expected to influence available grain surface area, which is known to correlate to reactivity. Commercial granular iron grains are platy and therefore pack in preferential orientations that could affect solution access to the surface. Three packing variations were investigated using Connelly Iron and trichloroethylene (TCE). Experimental kinetic data showed reaction rates 2-4 times higher when grains were packed with long axes preferentially parallel to flow (VP) compared to packings with long axes preferentially perpendicular to flow (HP) or randomly arranged (RP). The variations were found to be explainable by variations in reactive sorption capacities, i.e., sorption to sites where chemical transformations took place. The possibility that the different reactive sorption capacities were related to physical pore-scale differences was assessed by conducting an image analysis of the pore structure of sectioned columns. The analyses suggested that pore-scale factors - in particular the grain surface availability, reflected in the sorption capacity terms of the kinetic model used - could only account for a fraction of the observed reactivity differences between packing types. It is concluded that packing does affect observable reaction rates but that micro-scale features on the grain surfaces, rather than the pore scale characteristics, account for most of the apparent reactivity differences. This result suggests that treatability tests should consider the packing of columns carefully if they are to mimic field performance of PRBs to the greatest extent possible. PMID:25005796

Firdous, R; Devlin, J F

2014-08-01

309

Optimization of blended battery packs  

E-print Network

This thesis reviews the traditional battery pack design process for hybrid and electric vehicles, and presents a dynamic programming (DP) based algorithm that eases the process of cell selection and pack design, especially ...

Erb, Dylan C. (Dylan Charles)

2013-01-01

310

Robot Intelligence Leslie Pack Kaelbling  

E-print Network

Robot Intelligence Leslie Pack Kaelbling MIT CSAIL #12;A dream of robots Commercial reality Research frontier Leslie Pack Kaelbling, AAAI2010 #12;Robots and AI in artificial intelligence: planning, learning, reasoning, vision, natural language.... Leslie

Willsky, Alan S.

311

Corrosion inhibition for distillation apparatus  

DOEpatents

Tower material corrosion in an atmospheric or sub-atmospheric distillation tower in a coal liquefaction process is reduced or eliminated by subjecting chloride-containing tray contents to an appropriate ion-exchange resin to remove chloride from such tray contents materials.

Baumert, Kenneth L. (Emmaus, PA); Sagues, Alberto A. (Lexington, KY); Davis, Burtron H. (Georgetown, KY); Schweighardt, Frank K. (Upper Macungie, PA)

1985-01-01

312

Plant transpiration distillation of water  

SciTech Connect

A project using solar energy and the transpiration of plants for the distillation of water is described. Along with determining which of three plants thrived best growing in a still, the experiment also revealed that the still functioned nearly as well in inclement weather as in fair weather.

Virostko, M.K.; Spielberg, J.I.

1986-01-01

313

Distillation of hydrogen isotopes for polarized HD target  

E-print Network

We have developed a cryogenic distillation system to purify Hydrogen-Deuteride (HD) gas for a polarized HD target in LEPS experiments at SPring-8. A small amount of ortho-H$_2$ ($\\sim$0.01%) in the HD gas plays an important role in efficiently polarizing the HD target. Since there are 1$\\sim$5% impurities of H$_2$ and D$_2$ in commercially available HD gases, it is inevitable that the HD gas is purified up to $\\sim$99.99%. The distillation system has a cryogenic pot (17$\\sim$21 K) containing many small stainless steel cells called Heli-pack. Commercial HD gas with an amount of 5.2 mol is fed into the pot. We carried out three distillation runs by changing temperatures (17.5 K and 20.5 K) and gas extraction speeds (1.3 ml/min and 5.2 ml/min). The extracted gas was analyzed by using a gas analyzer system combining a quadrupole mass spectrometer with a gas chromatograph. The HD gas of 1 mol with a purity better than 99.99% has been successfully obtained. The effective NTS (Number of Theoretical Stages), which is...

Ohta, T; Didelez, J -P; Fujiwara, M; Fukuda, K; Kohri, H; Kunimatsu, T; Morisaki, C; Ono, S; Rouill', G; Tanaka, M; Ueda, K; Uraki, M; Utsuro, M; Wang, S Y; Yosoi, M

2011-01-01

314

Cadmium removal in a biosorption column  

Microsoft Academic Search

New biosorbent material derived from a ubiquitous brown marine alga Ascophyllum nodosum has been examined in packed-bed flow-through sorption columns. It effectively removed 10 mg\\/L of cadmium down to 1.5 ppb levels in the effluent, representing 99.985% removal. The experimental methodology used was based on the early Bohart and Adams sorption model, resulting in quantitative determination of the characteristic process

B. Volesky; I. Prasetyo

1994-01-01

315

SYNTHESIS OF HYDROCARBON STANDARDS Tetrahydrofuran (THF) was distilled from sodium/benzophenone under argon  

E-print Network

SYNTHESIS OF HYDROCARBON STANDARDS Tetrahydrofuran (THF) was distilled from sodium was equipped with a DB5-MS column (25 m Ã? 0.20 mm ID Ã? 0.33 2m film). Products were purified by flash or vacuum over anhydrous Na2SO4 and concentrated by rotary evaporation under partial vacuum. (n

Hanks, Lawrence M.

316

Determination of benzene and toluene in soils and plant material by azeotropic distillation  

SciTech Connect

The suspected dumping of gasoline near a garden resulted in the need for a method that would measure trace amounts of benzene and toluene in both soil and plant samples. In this report the authors show that a method involving methanolic extraction and azeotropic distillation is a highly sensitive technique that eliminated the contamination of the GC column by non-volatile material.

Kozloski, R.P.

1985-01-01

317

The interactions of design control and operability in reactive distillation systems  

Microsoft Academic Search

In this work the design and control of a reactive distillation column, described by a rigorous dynamic model, is tackled via two different optimization approaches. In the first, the steady-state process design and the control system are optimized sequentially. It is shown that operability is a strong function of the process design and potential operability bottlenecks are identified. In the

Michael C Georgiadis; Myrian Schenk; Efstratios N Pistikopoulos; Rafiqul Gani

2002-01-01

318

Universal Aircraft Seat Pack  

NASA Astrophysics Data System (ADS)

1 data display. Commands to the balloon are sent either by the computer or manually via thumb- wheels and the associated command encoder located on the front panel. The front panel commanding is backup for the computer commanding. Two redundant UHF command transmitters are used for up-link commanding to the balloon payload. Other Seat Pack features include an LDB Imarsat system for satellite data relay and a voice transceiver for air to ground voice communications with the operations center.

Barsic, J.; Depue, J.; Hadley, J.; Bunt, D.; Salter, R.

319

Computer simulation of the water and hydrogen distillation and CECE process and its experimental verification  

SciTech Connect

Mathematical simulation procedures have been developed for three processes of hydrogen isotopes separation: (1) a non steady-state water distillation; (2) a cryogenic distillation; and (3) a combined electrolysis and multistage water/hydrogen catalytic exchange (CECE) process. The simulation procedures possess some special features. Thus, the comparatively large step of integration and as a result of this high fast-acting is the peculiarity of the model for the dynamic behaviour of water distillation column operating at total reflux. The simulation procedure for CECE process considers six components and three phases (liquid water, water vapour, and hydrogen gas) and allows one to carry out computations for any mole fraction stock. This procedure, as the one for cryogenic distillation process, is not based on the Newton-Raphson method, and, in spite of this, convergence is reached by a small number of iterations (4 - 11). 8 refs., 4 figs., 6 tabs.

Fedorchenko, O.A.; Alekseev, I.A.; Trenin, V.D. [Petersburg Nuclear Physics Inst., Leningrad (Russian Federation); Uborski, V.V. [JVS DOL, Moscow (Russian Federation)

1995-10-01

320

Green chemical engineering aspects of reactive distillation.  

PubMed

Reactive or catalytic distillation technology combines chemical synthesis steps with separations by distillation. This combination can lead to intensified, high-efficiency process systems with significant green engineering attributes. New applications and understanding have prompted growth in the use of reactive distillation for a variety of chemical syntheses, especially esterifications and etherifications involving oxygenated hydrocarbons. We describe several applications and the potential and tradeoffs for reactive distillation technology in the context of green engineering principles. PMID:14700316

Malone, Michael F; Huss, Robert S; Doherty, Michael F

2003-12-01

321

Cascade Distillation Subsystem Development: Progress Toward a Distillation Comparison Test  

NASA Technical Reports Server (NTRS)

Recovery of potable water from wastewater is essential for the success of long-duration manned missions to the Moon and Mars. Honeywell International and a team from NASA Johnson Space Center (JSC) are developing a wastewater processing subsystem that is based on centrifugal vacuum distillation. The wastewater processor, referred to as the Cascade Distillation Subsystem (CDS), utilizes an innovative and efficient multistage thermodynamic process to produce purified water. The rotary centrifugal design of the system also provides gas/liquid phase separation and liquid transport under microgravity conditions. A five-stage subsystem unit has been designed, built, delivered and integrated into the NASA JSC Advanced Water Recovery Systems Development Facility for performance testing. A major test objective of the project is to demonstrate the advancement of the CDS technology from the breadboard level to a subsystem level unit. An initial round of CDS performance testing was completed in fiscal year (FY) 2008. Based on FY08 testing, the system is now in development to support an Exploration Life Support (ELS) Project distillation comparison test expected to begin in early 2009. As part of the project objectives planned for FY09, the system will be reconfigured to support the ELS comparison test. The CDS will then be challenged with a series of human-gene-rated waste streams representative of those anticipated for a lunar outpost. This paper provides a description of the CDS technology, a status of the current project activities, and data on the system s performance to date.

Callahan, M. R.; Lubman, A.; Pickering, Karen D.

2009-01-01

322

27 CFR 1.90 - Distilled spirits in bulk.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Distilled spirits in bulk. 1.90 Section 1.90 Alcohol, Tobacco...NONINDUSTRIAL USE OF DISTILLED SPIRITS AND WINE, BULK SALES AND BOTTLING OF DISTILLED SPIRITS Bulk Sales and Bottling of Distilled Spirits...

2010-04-01

323

Distillation of hydrogen isotopes for polarized HD target  

E-print Network

We have developed a cryogenic distillation system to purify Hydrogen-Deuteride (HD) gas for a polarized HD target in LEPS experiments at SPring-8. A small amount of ortho-H$_2$ ($\\sim$0.01%) in the HD gas plays an important role in efficiently polarizing the HD target. Since there are 1$\\sim$5% impurities of H$_2$ and D$_2$ in commercially available HD gases, it is inevitable that the HD gas is purified up to $\\sim$99.99%. The distillation system has a cryogenic pot (17$\\sim$21 K) containing many small stainless steel cells called Heli-pack. Commercial HD gas with an amount of 5.2 mol is fed into the pot. We carried out three distillation runs by changing temperatures (17.5 K and 20.5 K) and gas extraction speeds (1.3 ml/min and 5.2 ml/min). The extracted gas was analyzed by using a gas analyzer system combining a quadrupole mass spectrometer with a gas chromatograph. The HD gas of 1 mol with a purity better than 99.99% has been successfully obtained. The effective NTS (Number of Theoretical Stages), which is an indicator of the distillator performances, is obtained as 37.2$\\pm$0.6. This value is in reasonable agreement with a designed value of 37.9. The HD target is expected to be efficiently polarized under a well-controlled condition by doping an optimal amount of ortho-H$_2$ to the purified HD gas.

T. Ohta; S. Bouchigny; J. -P. Didelez; M. Fujiwara; K. Fukuda; H. Kohri; T. Kunimatsu; C. Morisaki; S. Ono; G. Rouill'; M. Tanaka; K. Ueda; M. Uraki; M. Utsuro; S. Y. Wang; M. Yosoi

2011-06-14

324

Enabling Microliquid Chromatography by Microbead Packing of Microchannels  

NASA Technical Reports Server (NTRS)

The microbead packing is the critical element required in the success of on-chip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and low-power element to separate amino acids and their chiral partners efficiently to understand better the origin of life. In order to densely pack microbeads into the microchannels, a liquid slurry of microbeads was created. Microbeads were extracted from a commercially available high-performance liquid chromatography column. The silica beads extracted were 5 microns in diameter, and had surface coating of phenyl-hexyl. These microbeads were mixed with a 200- proof ethanol solution to create a microbead slurry with the right viscosity for packing. A microfilter is placed at the outlet via of the microchannel and the slurry is injected, then withdrawn across a filter using modified syringes. After each injection, the channel is flushed with ethanol to enhance packing. This cycle is repeated numerous times to allow for a tightly packed channel of microbeads. Typical microbead packing occurs in the macroscale into tubes or channels by using highly pressurized systems. Moreover, these channels are typically long and straight without any turns or curves. On the other hand, this method of microbead packing is completed within a microchannel 75 micrometers in diameter. Moreover, the microbead packing is completed into a serpentine type microchannel, such that it maximizes microchannel length within a microchip. Doing so enhances the interactions of the analytes with the microbeads to separate efficiently amino acids and amino acid enantiomers.

Balvin, Manuel; Zheng, Yun

2014-01-01

325

Enabling Microliquid Chromatography by Microbead Packing of Microchannels  

NASA Technical Reports Server (NTRS)

The microbead packing is the critical element required in the success of on-chip microfabrication of critical microfluidic components for in-situ analysis and detection of chiral amino acids. In order for microliquid chromatography to occur, there must be a stationary phase medium within the microchannel that interacts with the analytes present within flowing fluid. The stationary phase media are the microbeads packed by the process discussed in this work. The purpose of the microliquid chromatography is to provide a lightweight, low-volume, and low-power element to separate amino acids and their chiral partners efficiently to understand better the origin of life. In order to densely pack microbeads into the microchannels, a liquid slurry of microbeads was created. Microbeads were extracted from a commercially available high-performance liquid chromatography column. The silica beads extracted were 5 microns in diameter, and had surface coating of phenyl-hexyl. These microbeads were mixed with a 200- proof ethanol solution to create a microbead slurry with the right viscosity for packing. A microfilter is placed at the outlet via of the microchannel and the slurry is injected, then withdrawn across a filter using modified syringes. After each injection, the channel is flushed with ethanol to enhance packing. This cycle is repeated numerous times to allow for a tightly packed channel of microbeads. Typical microbead packing occurs in the macroscale into tubes or channels by using highly pressurized systems. Moreover, these channels are typically long and straight without any turns or curves. On the other hand, this method of microbead packing is completed within a microchannel 75 micrometers in diameter. Moreover, the microbead packing is completed into a serpentine type microchannel, such that it maximizes microchannel length within a microchip. Doing so enhances the interactions of the analytes with the microbeads to separate efficiently amino acids and amino acid enantiomers.

Balvin, Manuel; Zheng, Yun

2013-01-01

326

Zenix SEC Column Manual Column Information  

E-print Network

1 Zenix SEC Column Manual Column Information Utilizing proprietary surface technologies and 3 m. They are compatible with most aqueous buffers, such as ammonium acetate, phosphate, tris, etc. When 150 mM phosphate phase: 150 mM Sodium Phosphate Buffer, pH 7 Flow rate: 1.0 mL/min Temperature: Ambient (~23° C

Lebendiker, Mario

327

Cadmium removal in a biosorption column  

SciTech Connect

New biosorbent material derived from a ubiquitous brown marine alga Ascophyllum nodosum has been examined in packed-bed flow-through sorption columns. It effectively removed 10 mg/L of cadmium down to 1.5 ppb levels in the effluent, representing 99.985% removal. The experimental methodology used was based on the early Bohart and Adams sorption model, resulting in quantitative determination of the characteristic process parameters which can be used for performance comparison and process design. An average metal loading of the biosorbent (N[sub 0]) determined was 30 mg Cd/g, corresponding closely to that observed for the batch equilibrium metal concentration of 10 mg Cd/L. The critical bed depth (D[sub min]) for the potable water effluent quality standard varied with the column feed flow rate from 20 to 50 cm. The sorption column mass transfer and dispersion coefficients were determined, which are also required for solving the sorption model equations.

Volesky, B.; Prasetyo, I. (McGill Univ., Montreal, Quebec (Canada). Dept. of Chemical Engineering)

1994-05-01

328

Dense periodic packings of tori  

E-print Network

Dense packings of nonoverlapping bodies in three-dimensional Euclidean space are useful models of the structure of a variety of many-particle systems that arise in the physical and biological sciences. Here we investigate the packing behavior of congruent ring tori, which are multiply connected nonconvex bodies of genus 1, as well as horn and spindle tori. We analytically construct a family of dense periodic packings of unlinked tori guided by the organizing principles originally devised for simply connected solid bodies [Torquato and Jiao, PRE 86, 011102 (2012)]. We find that the horn tori as well as certain spindle and ring tori can achieve a packing density higher than the densest known packing of both sphere and ellipsoids. In addition, we study dense packings of cluster of pair-linked ring tori (i.e., Hopf links).

Ruggero Gabbrielli; Yang Jiao; Salvatore Torquato

2014-02-26

329

Five points on columns  

E-print Network

Column,” like “gene,” has both conceptual and linguistic shortcomings. The simple question “what is a column” is not easy to answer and the word itself is not easy to replace. In the present article, I have selected five ...

Rockland, Kathleen

330

Granular packings and fault zones  

PubMed

The failure of a two-dimensional packing of elastic grains is analyzed using a numerical model. The packing fails through formation of shear bands or faults. During failure there is a separation of the system into two grain-packing states. In a shear band, local "rotating bearings" are spontaneously formed. The bearing state is favored in a shear band because it has a low stiffness against shearing. The "seismic activity" distribution in the packing has the same characteristics as that of the earthquake distribution in tectonic faults. The directions of the principal stresses in a bearing are reminiscent of those found at the San Andreas Fault. PMID:11017335

Astrom; Herrmann; Timonen

2000-01-24

331

Method for dense packing discovery.  

PubMed

The problem of packing a system of particles as densely as possible is foundational in the field of discrete geometry and is a powerful model in the material and biological sciences. As packing problems retreat from the reach of solution by analytic constructions, the importance of an efficient numerical method for conducting de novo (from-scratch) searches for dense packings becomes crucial. In this paper, we use the divide and concur framework to develop a general search method for the solution of periodic constraint problems, and we apply it to the discovery of dense periodic packings. An important feature of the method is the integration of the unit-cell parameters with the other packing variables in the definition of the configuration space. The method we present led to previously reported improvements in the densest-known tetrahedron packing. Here, we use the method to reproduce the densest-known lattice sphere packings and the best-known lattice kissing arrangements in up to 14 and 11 dimensions, respectively, providing numerical evidence for their optimality. For nonspherical particles, we report a dense packing of regular four-dimensional simplices with density ?=128/219?0.5845 and with a similar structure to the densest-known tetrahedron packing. PMID:21230619

Kallus, Yoav; Elser, Veit; Gravel, Simon

2010-11-01

332

PULSE COLUMN DESIGN  

Microsoft Academic Search

A stagewise approach was used in a theoretical analysis of pulse columns. ;\\u000a In the analysis the column was arbitrarily divided into discrete stages ;\\u000a comprising that part of the column between two adjacent perforated plates. The ;\\u000a operation of the pulse column was described mathematically using material balance ;\\u000a equations, and a design method was derived which used two

L. E. Burkhart; R. W. Fahien

1958-01-01

333

JCE Feature Columns  

Microsoft Academic Search

The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using

Jon L. Holmes

1999-01-01

334

Computational Fluid Dynamics Simulation of Structured Packing Scott A. Owens, Michael R. Perkins, and R. Bruce Eldridge*  

E-print Network

was imported into a three-dimensional imaging program and then copied, translated, and rotated to create to approximate a packed column. The resulting three-dimensional image file was imported into the Star-CCM+ CFD packing. Grid generation was performed automatically using adaptive mesh generation software with user

Eldridge, R. Bruce

335

Liquid chromatography on soft packing material, under axial compression  

Microsoft Academic Search

The behaviour of Sephadex G-25 gel packing for size-exclusion chromatography under dynamic axial compression in a 100×2.5 cm column of original design has been studied. The influence of dynamic axial compression on the bed structure and its chromatographic performance was determined with polypeptide samples of various molecular mass. In the studied range of compression pressure values (1.74–5.22 bar), a considerable

A. V. Danilov; I. V. Vagenina; L. G. Mustaeva; S. A. Moshnikov; E. Yu Gorbunova; V. V. Cherskii; M. B. Baru

1997-01-01

336

Vapor Compression Distillation Flight Experiment  

NASA Technical Reports Server (NTRS)

One of the major requirements associated with operating the International Space Station is the transportation -- space shuttle and Russian Progress spacecraft launches - necessary to re-supply station crews with food and water. The Vapor Compression Distillation (VCD) Flight Experiment, managed by NASA's Marshall Space Flight Center in Huntsville, Ala., is a full-scale demonstration of technology being developed to recycle crewmember urine and wastewater aboard the International Space Station and thereby reduce the amount of water that must be re-supplied. Based on results of the VCD Flight Experiment, an operational urine processor will be installed in Node 3 of the space station in 2005.

Hutchens, Cindy F.

2002-01-01

337

Heat Transfer Analysis for a Fixed CST Column  

SciTech Connect

In support of a small column ion exchange (SCIX) process for the Savannah River Site waste processing program, a transient two-dimensional heat transfer model that includes the conduction process neglecting the convection cooling mechanism inside the crystalline silicotitanate (CST) column has been constructed and heat transfer calculations made for the present design configurations. For this situation, a no process flow condition through the column was assumed as one of the reference conditions for the simulation of a loss-of-flow accident. A series of the modeling calculations has been performed using a computational heat transfer approach. Results for the baseline model indicate that transit times to reach 130 degrees Celsius maximum temperature of the CST-salt solution column are about 96 hours when the 20-in CST column with 300 Ci/liter heat generation source and 25 degrees Celsius initial column temperature is cooled by natural convection of external air as a primary heat transfer mechanism. The modeling results for the 28-in column equipped with water jacket systems on the external wall surface of the column and water coolant pipe at the center of the CST column demonstrate that the column loaded with 300 Ci/liter heat source can be maintained non-boiling indefinitely. Sensitivity calculations for several alternate column sizes, heat loads of the packed column, engineered cooling systems, and various ambient conditions at the exterior wall of the column have been performed under the reference conditions of the CST-salt solution to assess the impact of those parameters on the peak temperatures of the packed column for a given transient time. The results indicate that a water-coolant pipe at the center of the CST column filled with salt solution is the most effective one among the potential design parameters related to the thermal energy dissipation of decay heat load. It is noted that the cooling mechanism at the wall boundary of the column has significant impact on maximum and wall temperatures of the column. In addition, the results computed by the present model were verified by the theoretical results. The analysis results will provide quantitative information associated with the process heat control and management of the CST base design. For example, transient responses of the CST system under a loss-of-flow accident condition will provide safety design information for an emergency cooling system of the column.

Lee, S.Y.

2004-02-19

338

How To Run a Flash Column Contributed by Jeffrey Bode  

E-print Network

-6 column volumes worth to flow though, to ensure complete packing. Now elute all of the solvent with air and concentrating to a few mL volume and repeating this several times. As acetic acid boils at a lower bp than gel is added dry. Usually, it is best if the silica is not too long, about 6 to 10 inches is best

Yao, Shao Q

339

A new procedure for the determination of distillation temperature distribution of high-boiling petroleum products and fractions.  

PubMed

The distribution of distillation temperatures of liquid and semi-fluid products, including petroleum fractions and products, is an important process and practical parameter. It provides information on properties of crude oil and content of particular fractions, classified on the basis of their boiling points, as well as the optimum conditions of atmospheric or vacuum distillation. At present, the distribution of distillation temperatures is often investigated by simulated distillation (SIMDIS) using capillary gas chromatography (CGC) with a short capillary column with polydimethylsiloxane as the stationary phase. This paper presents the results of investigations on the possibility of replacing currently used CGC columns for SIMDIS with a deactivated fused silica capillary tube without any stationary phase. The SIMDIS technique making use of such an empty fused silica column allows a considerable lowering of elution temperature of the analytes, which results in a decrease of the final oven temperature while ensuring a complete separation of the mixture. This eliminates the possibility of decomposition of less thermally stable mixture components and bleeding of the stationary phase which would result in an increase of the detector signal. It also improves the stability of the baseline, which is especially important in the determination of the end point of elution, which is the basis for finding the final temperature of distillation. This is the key parameter for the safety process of hydrocracking, where an excessively high final temperature of distillation of a batch can result in serious damage to an expensive catalyst bed. This paper compares the distribution of distillation temperatures of the fraction from vacuum distillation of petroleum obtained using SIMDIS with that obtained by the proposed procedure. A good agreement between the two procedures was observed. In addition, typical values of elution temperatures of n-paraffin standards obtained by the two procedures were compared. Finally, the agreement between boiling points of polar compounds determined from their retention times and actual boiling points was investigated. PMID:21153592

Boczkaj, Grzegorz; Przyjazny, Andrzej; Kami?ski, Marian

2011-03-01

340

Two separation modes combined in one column: sequential ion-exchange separation and size-exclusion chromatography of green fluorescent protein  

Microsoft Academic Search

Purification of green fluorescent protein from a crude solution has been investigated using a combined system of ion-exchange chromatography and size-exclusion chromatography packed into one column of a continuous annular chromatograph. Performing the chromatography with two different sorbents packed into a single column reduces transfer losses and the hold steps between the two separation steps can be eliminated. Appropriate running

Andrea Uretschlaeger; Alois Jungbauer

2002-01-01

341

Distillation of Bell states in open systems  

E-print Network

In this work we review the entire classification of 2x2 distillable states for protocols with a finite numbers of copies. We show a distillation protocol that allows to distill Bell states with non zero probability at any time for an initial singlet in vacuum. It is shown that the same protocol used in non zero thermal baths yields a considerable recovering of entanglement.

E. Isasi; D. Mundarain

2009-08-14

342

Distillation of Bell states in open systems  

E-print Network

In this work we review the entire classification of 2x2 distillable states for protocols with a finite numbers of copies. We show a distillation protocol that allows to distill Bell states with non zero probability at any time for an initial singlet in vacuum. It is shown that the same protocol used in non zero thermal baths yields a considerable recovering of entanglement.

Isasi, E

2009-01-01

343

3D printed metal columns for capillary liquid chromatography.  

PubMed

Coiled planar capillary chromatography columns (0.9 mm I.D. × 60 cm L) were 3D printed in stainless steel (316L), and titanium (Ti-6Al-4V) alloys (external dimensions of ?5 × 30 × 58 mm), and either slurry packed with various sized reversed-phase octadecylsilica particles, or filled with an in situ prepared methacrylate based monolith. Coiled printed columns were coupled directly with 30 × 30 mm Peltier thermoelectric direct contact heater/cooler modules. Preliminary results show the potential of using such 3D printed columns in future portable chromatographic devices. PMID:25285334

Sandron, S; Heery, B; Gupta, V; Collins, D A; Nesterenko, E P; Nesterenko, P N; Talebi, M; Beirne, S; Thompson, F; Wallace, G G; Brabazon, D; Regan, F; Paull, B

2014-11-10

344

Packing Steiner trees Microsoft Research  

E-print Network

@cs.toronto.edu Abstract The Steiner packing problem is to #12;nd the maximum number of edge-disjoint subgraphs of a given Steiner tree problem via the ellipsoid algorithm. 1 Introduction In the Steiner tree packing problem practical as well as theoretical considerations. The problem in its full generality (where for each Steiner

Salavatipour, Mohammad R.

345

Method for gravel packing wells  

SciTech Connect

This patent describes a method for gravel packing a perforated well which penetrates a formation or reservoir. It comprises placing into a solution a shear-thickening composition in an amount sufficient to form a carrier fluid having a viscosity sufficient to suspend gravel packing sand therein for a time sufficient to pack the well; adding gravel packing sand into the fluid thereby suspending the sand therein; injecting the carrier fluid and sand mixture into the well under conditions sufficient to cause the mixture to shear thicken so as to provide for transportation of the sand to perforations in the well without spreading from the mixture; and directing the mixture into the perforations which diminishes shear forces acting on the mixture thereby causing a reduction in viscosity of the carrier fluid, sand separation from the fluid, improved fluid leak-off into the formation, and uniform gravel packing of the perforations.

Yeh, C.S.

1991-12-31

346

Amino acid analysis using core-shell particle column.  

PubMed

In this study, the separation efficiency of a core-shell particle column was compared with particle-packed and monolithic silica columns, which showed that the core-shell particle column had a smaller theoretical plate height and that its separation efficiency was not affected significantly by the increase in flow rate. A fast HPLC method using a core-shell particle column was developed for the determination of amino acids. 4-Fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was used as a fluorescence derivatization reagent for amino acids, followed by separation on a core-shell Kinetex C18 column. The analysis time for 21 NBD-amino acids was within 7min, which was faster than that in our previous studies with conventional particle-packed columns or monolithic silica columns. The linearities of the calibration curves for all the amino acids were found to be good over a range of injection amounts from 40fmol to 40pmol. The accuracies for the amino acid determinations were 90.9-107%. The method was proved to have potential for the fast determination of amino acids in biological samples. PMID:23022276

Song, Yanting; Funatsu, Takashi; Tsunoda, Makoto

2013-05-15

347

EFFECT OF NITRATE-BASED BIOREMEDIATION ON CONTAMINANT DISTRIBUTION AND SEDIMENT TOXICITY-COLUMN STUDY  

EPA Science Inventory

A laboratory column study was set up to evaluate changes in contaminant distribution and sediment toxicity following nitrate-based bioremediation and to correlate toxicity reduction with loss of fuel components. Glass columns were packed with sediment from an aquifer that had be...

348

Influence of methanol on retention of hydrophobic organic chemicals in soil leaching column chromatography  

Microsoft Academic Search

The influence of methanol in methanol–water mixed eluents on the capacity factor (k?), an important parameter which could depict leaching potential of hydrophobic organic chemicals (HOCs) in soil leaching column chromatography (SLCC), was investigated. Two reference soils, GSE 17201 obtained from Bayer Landwirtschaftszentrum, Monheim, Germany and SP 14696 from LUFA, Spencer, Germany, were used as packing materials in soil columns,

Feng Xu; Xinmiao Liang; Bingcheng Lin; Fan Su; Karl-Werner Schramm; Antonius Kettrup

2002-01-01

349

Monolithic columns containing sol–gel bonded octadecylsilica for capillary electrochromatography  

Microsoft Academic Search

A new method for preparing monolithic capillary columns is reported. A fused-silica capillary packed with porous octadecylsilica (ODS) particles using a CO2 slurry was partially filled with a siliceous sol formed by hydrolysis and polycondensation of tetramethoxysilane and ethyltrimethoxysilane. After gelling and aging of the siliceous sol at room temperature, the column was dried with supercritical CO2. The scanning electron

Qinglin Tang; Baomin Xin; Milton L Lee

1999-01-01

350

Use of specially designed columns for antioxidants and antimicrobials enrichment by preparative supercritical fluid chromatography  

Microsoft Academic Search

A new, specially designed column has been developed for fractionation of supercritical fluid extract of rosemary by using a preparative supercritical fluid chromatography system (Prep-SFC). The column evaluated in this work was prepared using a new packing method consisting of a combination of slurry and supercritical CO2 with commercial silica particles coated with a stationary phase commonly used in gas

Pilar Ramírez; Susana Santoyo; Mónica R. García-Risco; F. Javier Señoráns; Elena Ibáñez; Guillermo Reglero

2007-01-01

351

TRANSPORT OF MACROMOLECULES AND HUMATE COLLOIDS THROUGH A SAND AND A CLAY AMENDED SAND LABORATORY COLUMN  

EPA Science Inventory

Laboratory experiments were conducted to determine if macromolecules or humate colloids would transport through sand columns and if they would exhibit any variations in their relative velocity based upon their molecular volumes and the pore size distribution of the column packing...

352

Evaluating Defoaming Agents for the Stripping Columns at the In-Tank Precipitation Facility  

Microsoft Academic Search

The In-Tank Precipitation (ITP) process will concentrate the Tank 48 contents to approximately 10 wt. percent tetraphenylborate solids by filtration. The filtrate produced during the process flows to the ITP stripping columns where the soluble benzene is removed from the solution. It has been observed that a large pressure differential occurs across the column packing when the filtrate is processed

McGlynn

1993-01-01

353

Treatment of Aroclor 1016 contaminated soil by hydrogen peroxide: laboratory column study  

Microsoft Academic Search

The potential and feasibility of treating soil contaminated with electrical insulating oil, Aroclor 1016, containing polychlorinated biphenyls (PCBs) with stabilized hydrogen peroxide were evaluated using columns packed with soils of two different matrixes. The column experiments showed that PCBs degraded by the stabilized hydrogen peroxide treatment in both soil matrixes, although the efficacy of the treatment depended strongly on the

Marika Viisimaa; Jelena Veressinina; Anna Goi

2012-01-01

354

Inelastic column behavior  

NASA Technical Reports Server (NTRS)

The significant findings of a theoretical study of column behavior in the plastic stress range are presented. When the behavior of a straight column is regarded as the limiting behavior of an imperfect column as the initial imperfection (lack of straightness) approaches zero, the departure from the straight configuration occurs at the tangent-modulus load. Without such a concept of the behavior of a straight column, one is led to the unrealistic conclusion that lateral deflection of the column can begin at any load between the tangent-modulus value and the Euler load, based on the original elastic modulus. A family of curves showing load against lateral deflection is presented for idealized h-section columns of various lengths and of various materials that have a systematic variation of their stress-strain curves.

Duberg, John E; Wilder, Thomas W , III

1952-01-01

355

Quality evaluation of agricultural distillates using different types of electronic noses  

NASA Astrophysics Data System (ADS)

The paper presents the results of investigation on quality evaluation of agricultural distillates using a prototype of electronic nose instrument and a commercial electronic nose of Fast/Flash GC type- HERACLES II. The prototype was equipped with TGS type semiconductor sensors. HERACLES II included two chromatographic columns with different polarity of stationary phase and two FID detectors. In case of the prototype volatile fraction of the agricultural distillate was prepared via barbotage process, whereas HERACLES II analysed the headspace fraction. Classification of the samples into three quality classes was performed using: quadratic discriminant function (QDA), supported with cross-validation method. Over 95% correct classification of the agricultural distillates into particular quality classes was observed for the analyses with HERACLES II. The prototype of electronic nose provided correct classification at the level of 70%.

Dymerski, Tomasz; Gebicki, Jacek; Namie?nik, Jacek

2014-08-01

356

Yeast Genomic DNA Prep Sterile distilled water  

E-print Network

Auble Lab Yeast Genomic DNA Prep Reagents: Sterile distilled water -mercaptoethanol Sorbitol Buffer conical tube at 3,000 rpms for 5 minutes. 3. Resuspend in 10 ml of sterile distilled (SD) water, then spin for 5 minutes at 3,000 rpms and decant off water. 4. Resuspend in 5 ml of SD water and add 100 µl

Auble, David

357

Topic distillation via sub-site retrieval  

Microsoft Academic Search

Topic distillation is one of the main information needs when users search the Web. Previous approaches for topic dis- tillation treat single page as the basic searching unit, which has not fully utilized the structure information of the Web. In this paper, we propose a novel concept for topic distillation, named sub-site retrieval, in which the basic searching unit is

Tao Qin; Tie-yan Liu; Xu-dong Zhang; Guang Feng; De-sheng Wang; Wei-ying Ma

2007-01-01

358

Distillability Criterion for all Bipartite Gaussian States  

E-print Network

We prove that all inseparable Gaussian states of two modes can be distilled into maximally entangled pure states by local operations. Using this result we show that a bipartite Gaussian state of arbitrarily many modes can be distilled if and only if its partial transpose is not positive.

G. Giedke; L. -M. Duan; J. I. Cirac; P. Zoller

2001-04-13

359

Dog pack attack: hunting humans.  

PubMed

Dog bite-related fatalities, although unusual, accounted for 304 deaths in the United States between 1979 and 1996 and 6 fatalities in Canada between 1994 and 1996. Fatal dog pack attacks and attacks involving human predation are less common. The following describes a dog pack attack on a family of four involving 2 fatalities with predation of the victims. Factors previously identified that contribute to pack attacks and predation, including prior group hunting, social feeding, territorial defense, lack of human interaction, and prey stimuli, are discussed. PMID:10507791

Avis, S P

1999-09-01

360

Comparison of advanced distillation control methods. Second annual report  

SciTech Connect

Detailed dynamic simulations of three industrial distillation columns (a propylene/propane splitter, a xylene/toluene column, and a depropanizer) have been used to study the issue of configuration selection for diagonal PI dual composition controls. ATV identification with on-line detuning was used for tuning the diagonal PI composition controllers. Each configuration was evaluated with respect to steady-state RGA values, sensitivity to feed composition changes, and open loop dynamic performance. Each configuration was tuned using setpoint changes over a wider range of operation for robustness and tested for feed composition upsets. Overall, configuration selection was shown to have a dominant effect upon control performance. Configuration analysis tools (e.g., RGA, condition number, disturbance sensitivity), were found to reject configuration choices that are obviously poor choices, but were unable to critically differentiate between the remaining viable choices. Configuration selection guidelines are given although it is demonstrated that the most reliable configuration selection approach is based upon testing the viable configurations using dynamic column simulators.

NONE

1996-11-01

361

Intrinsic biodegradation of toluene coupled to the microbial reduction of ferric iron: laboratory column experiments  

Microsoft Academic Search

Intrinsic biodegradation of toluene coupled with the microbial reduction of ferric iron (Fe(III)) as the terminal electron acceptor was studied by using laboratory column experiments under continuous flow conditions. Columns were packed with contaminated aquifer sediment and N2-purged groundwater taken from the western part of the Gardermoen aquifer. The columns were operated anaerobically at 8 °C (in-situ temperature). Chloride was

Zuoping Zheng; Per Aagaard; Gijs D. Breedveld

2002-01-01

362

27 CFR 19.65 - Experimental distilled spirits plants.  

Code of Federal Regulations, 2010 CFR

...false Experimental distilled spirits plants. 19.65 Section 19.65 Alcohol...TREASURY LIQUORS DISTILLED SPIRITS PLANTS Administrative and Miscellaneous Provisions...65 Experimental distilled spirits plants. The appropriate TTB officer may...

2010-04-01

363

7 CFR 160.8 - Steam distilled wood turpentine.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8 ...STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind...

2010-01-01

364

7 CFR 160.9 - Destructively distilled wood turpentine.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Destructively distilled wood turpentine. 160.9 Section 160.9...General § 160.9 Destructively distilled wood turpentine. The designation “destructively distilled wood turpentine” shall refer to the kind...

2012-01-01

365

7 CFR 160.9 - Destructively distilled wood turpentine.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Destructively distilled wood turpentine. 160.9 Section 160.9...General § 160.9 Destructively distilled wood turpentine. The designation “destructively distilled wood turpentine” shall refer to the kind...

2013-01-01

366

7 CFR 160.9 - Destructively distilled wood turpentine.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Destructively distilled wood turpentine. 160.9 Section 160.9...General § 160.9 Destructively distilled wood turpentine. The designation “destructively distilled wood turpentine” shall refer to the kind...

2011-01-01

367

7 CFR 160.9 - Destructively distilled wood turpentine.  

...2014-01-01 false Destructively distilled wood turpentine. 160.9 Section 160.9...General § 160.9 Destructively distilled wood turpentine. The designation “destructively distilled wood turpentine” shall refer to the kind...

2014-01-01

368

7 CFR 160.8 - Steam distilled wood turpentine.  

... 2014-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8 ...STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind...

2014-01-01

369

7 CFR 160.8 - Steam distilled wood turpentine.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8 ...STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind...

2011-01-01

370

7 CFR 160.8 - Steam distilled wood turpentine.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8 ...STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind...

2013-01-01

371

7 CFR 160.8 - Steam distilled wood turpentine.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8 ...STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind...

2012-01-01

372

7 CFR 160.9 - Destructively distilled wood turpentine.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Destructively distilled wood turpentine. 160.9 Section 160.9...General § 160.9 Destructively distilled wood turpentine. The designation “destructively distilled wood turpentine” shall refer to the kind...

2010-01-01

373

27 CFR 19.32 - Experimental distilled spirits plants.  

...false Experimental distilled spirits plants. 19.32 Section 19.32 Alcohol...TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Administrative and Miscellaneous Provisions...32 Experimental distilled spirits plants. (a) General. The...

2014-04-01

374

27 CFR 19.32 - Experimental distilled spirits plants.  

Code of Federal Regulations, 2011 CFR

...false Experimental distilled spirits plants. 19.32 Section 19.32 Alcohol...TREASURY LIQUORS DISTILLED SPIRITS PLANTS Administrative and Miscellaneous Provisions...32 Experimental distilled spirits plants. (a) General. The...

2011-04-01

375

Dynamic analysis of thermally coupled distillation sequences with undirectional flows for the separation of ternary mixtures  

Microsoft Academic Search

The Petlyuk distillation system has been considered with special interest because of the high energy savings it can provide\\u000a with respect to the operation of sequences based on conventional columns. The original design of the Petlyuk structure, however,\\u000a shows two interconnections that seem to affect its operational and controllability properties. To overcome this problem, two\\u000a alternate structures have been suggested

Juan Gabriel Segovia-Hernández; Adrián Bonilla-Petriciolet; Luis Ignacio Salcedo-Estrada

2006-01-01

376

The synthesis of thermally coupled distillation flowsheets for separations of five-component mixtures  

Microsoft Academic Search

The thermally coupled distillation flowsheets for separation of five-component mixtures are studied based on the total annual costs. Fourteen simple column sequences and some feasible thermally coupled configurations with side strippers and\\/or side rectifiers are considered. The costs of the flowsheets are calculated and compared for several real five-component mixtures with various relative volatility distributions and a wide range of

Ben-Guang Rong; Andrzej Kraslawski; Lars Nyström

2000-01-01

377

Stochastic packing-market planning  

Microsoft Academic Search

Motivated by the problem of centralized market clearing in a mar- ket with probabilistic supply and demand, we introduce the Stochas- tic Packing-Market Planning problem (SPMP), which is a stochas- tic generalization of the Maximum k-Set Packing problem. We provide an O(k) approximation algorithm for SPMP, as well as a O(k) approximation mechanism that is truthful in expectation. This matches

Daniel Golovin

2007-01-01

378

Size exclusion chromatography on soft and semi-rigid packing materials in the dynamic axial compression mode.  

PubMed

The effect of dynamic axial compression within a range of up to 5 bar upon the structure of the bed packed with soft and semi-rigid packing materials (Sephadex G-25, Bio-Gel P2 and Toyopearl HW-40) and the associated chromatographic parameters were studied for size exclusion chromatography. Continuous packing compression is accomplished by use of a special column with controlled external pressure applied to the packing. Compression has been shown to favor an overall increase in the resolution with pressure optima observed in some cases. PMID:12915005

Baru, M B; Danilov, A V; Vagenina, I V

2003-08-29

379

The book review column  

Microsoft Academic Search

Welcome to the Book Reviews Column. We hope to bring you at least two reviews of books every month. In this column four books are reviewed. 1. Stable Marriage and its Relation to Other Combinatorial Problems: An Intro- duction to Algorithm Analysis by Donald Knuth. Reviewed by Tim McNichol. This book uses the stable marriage problem as motivation to look

William I. Gasarch

2004-01-01

380

Inflatable Column Structure  

NASA Technical Reports Server (NTRS)

Lightweight structural member easy to store. Billowing between circumferential loops of fiber inflated column becomes series of cells. Each fiber subjected to same tension along entire length (though tension is different in different fibers). Member is called "isotensoid" column. Serves as jack for automobiles or structures during repairs. Also used as support for temporary bleachers or swimming pools.

Hedgepeth, J. M.

1985-01-01

381

Medial column stabilization.  

PubMed

This article presented a brief review of medial column stabilizing procedures. The various types of procedures that have been advocated for different deformities have been discussed. It is important to keep in mind that fusion of any of the medial column joints should not be performed as an isolated procedure in flexible flatfoot deformity. Medial column stabilization is only a component procedure when surgically managing a flexible flatfoot. When choosing procedures to correct a flexible flatfoot, thorough preoperative evaluation is important. It is also important to realize that conservative measures should be exhausted before attempting any type of stabilization of the medial column for flexible flatfoot deformity. Specific criteria for flexible flatfoot surgery should include severe uncontrollable deformity, an inability to wear standard foot gear, and persistent pain and disability despite exhaustive conservative therapy. A medial column stabilization is also an excellent procedure for those patients who have end-stage degenerative joint disease of the medial longitudinal arch. PMID:1893342

Catanzariti, A R

1991-07-01

382

JCE Feature Columns  

NASA Astrophysics Data System (ADS)

The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad in the Chemistry Curriculum, and WWW Site Review. These columns differ from the print feature columns in that they use the Internet as the publication medium. Doing so allows these features to include continually updated information, digital components, and links to other online resources. The Conceptual Questions and Challenge Problems feature of JCE Internet serves as a good example for the kinds of resources that you can expect to find in an online feature column. Like other columns it contains a mission statement that defines the role of the column. It includes a digital library of continually updated examples of conceptual questions and challenge problems. (As I write this we have just added several new questions to the library.) It also includes a list of links to related online resources, information for authors about how to write questions and problems, and information for teachers about how to use conceptual questions and challenge problems. Teaching with Technology home page at JCE Online. One-Stop Feature Shop The updated Feature area of JCE Online offers information about all JCE feature columns in one place. It gives you a quick and convenient way to access a group of articles in a particular subject area. It provides authors and readers with a good definition of the column and its mission. It complements the print feature columns with online resources. It provides up-to-date bibliographies for selected areas of interest. And last, but not least, it provides that email address you can use to send that message of appreciation to the feature editor for his or her contribution to JCE and the chemical education community.

Holmes, Jon L.

1999-05-01

383

Separation characteristics of multistage water/hydrogen exchange column for water detritiation in fusion reactors  

SciTech Connect

A simulation code of multistage chemical exchange columns has been developed. The sieve trays for liquid-vapor scrubbing and the catalyst beds for vapor-hydrogen exchange reactions are alternately piled within the column. The code deals with all the twelve molecular species of hydrogen gas and water; and is based on the Newton-Raphson method. The characteristics of the column were discussed from the calculated results by this code such as effects of temperature and pressure. Similar to the distillation columns, the phase flow rates within the column (hydrogen gas and water vapor) and product flow rates have large effects on the separation performance of the column. A control method of the column was also proposed from these calculated results. 9 refs., 5 figs., 4 tabs.

Yamanishi, T.; Okuno, K. [Japan Atomic Energy Research Lab., Ibaraki (Japan)

1995-10-01

384

High speed solvating gas chromatography using packed capillaries containing sub-5 ?m particles  

Microsoft Academic Search

In this study, fused-silica capillaries of 250 ?m I.D. were packed with spherical porous and nonporous octadecyl bonded silica particles having diameters of 1.5 and 3 ?m. These capillaries were used with CO2 as mobile phase at elevated temperatures. At the column inlet, the mobile phase was a supercritical fluid, while at the column outlet, it was a gas. The

Yufeng Shen; Milton L. Lee

1997-01-01

385

Cascade Distiller System Performance Testing Interim Results  

NASA Technical Reports Server (NTRS)

The Cascade Distillation System (CDS) is a rotary distillation system with potential for greater reliability and lower energy costs than existing distillation systems. Based upon the results of the 2009 distillation comparison test (DCT) and recommendations of the expert panel, the Advanced Exploration Systems (AES) Water Recovery Project (WRP) project advanced the technology by increasing reliability of the system through redesign of bearing assemblies and improved rotor dynamics. In addition, the project improved the CDS power efficiency by optimizing the thermoelectric heat pump (TeHP) and heat exchanger design. Testing at the NASA-JSC Advanced Exploration System Water Laboratory (AES Water Lab) using a prototype Cascade Distillation Subsystem (CDS) wastewater processor (Honeywell d International, Torrance, Calif.) with test support equipment and control system developed by Johnson Space Center was performed to evaluate performance of the system with the upgrades as compared to previous system performance. The system was challenged with Solution 1 from the NASA Exploration Life Support (ELS) distillation comparison testing performed in 2009. Solution 1 consisted of a mixed stream containing human-generated urine and humidity condensate. A secondary objective of this testing is to evaluate the performance of the CDS as compared to the state of the art Distillation Assembly (DA) used in the ISS Urine Processor Assembly (UPA). This was done by challenging the system with ISS analog waste streams. This paper details the results of the AES WRP CDS performance testing.

Callahan, Michael R.; Pensinger, Stuart; Sargusingh, Miriam J.

2014-01-01

386

An Aggregation Model Reduction Method for One-Dimensional Distributed Systems  

E-print Network

packed distillation columns, fixed-bed reactors, and heat exchangers. A special class of discrete systems a distillation column, a heat exchanger, and a fixed-bed reactor. VVC 2011 Ameri- can Institute of Chemical

Skogestad, Sigurd

387

An aggregation model reduction method for one-dimensional distributed systems  

E-print Network

, or continuous, like packed distillation columns, fixed-bed reactors, and heat exchangers. A special class example systems, namely a distillation column, a heat exchanger, and a fixed-bed reactor. Keywords Model

Skogestad, Sigurd

388

Nature of packs used in propellant modeling.  

PubMed

In recent years we have constructed closely packed spheres using the Lubachevsky-Stillinger algorithm to generate morphological models of heterogeneous solid propellants. Improvements to the algorithm now allow us to create large polydisperse packs on a laptop computer, and to create monodisperse packs with packing fractions greater than 70% which display significant crystal order. The use of these models in the physical context motivates efforts to examine in some detail the nature of the packs, including certain statistical properties. We compare packing fractions for binary packs with long-known experimental data. Also, we discuss the near-neighbor number and the radial distribution function (RDF) for monodisperse packs and make comparisons with experimental data. We also briefly discuss the RDF for bidisperse packs. We also consider bounded monodisperse packs, and pay particular attention to the near-wall structure where we identify significant order. PMID:18517690

Maggi, F; Stafford, S; Jackson, T L; Buckmaster, J

2008-04-01

389

Minimizing corrosion in coal liquid distillation  

DOEpatents

In an atmospheric distillation tower of a coal liquefaction process, tower materials corrosion is reduced or eliminated by introduction of boiling point differentiated streams to boiling point differentiated tower regions.

Baumert, Kenneth L. (Emmaus, PA); Sagues, Alberto A. (Lexington, KY); Davis, Burtron H. (Georgetown, KY)

1985-01-01

390

27 CFR 19.301 - Distillation.  

Code of Federal Regulations, 2011 CFR

...operations are continuous. The collection of unfinished spirits for the purpose of redistillation is not considered to be a break in the continuity of the distilling procedure. However, the quantity and proof of any unfinished spirits must be...

2011-04-01

391

Development of energy efficient membrane distillation systems  

E-print Network

Membrane distillation (MD) has shown potential as a means of desalination and water purification. As a thermally driven membrane technology which runs at relatively low pressure, which can withstand high salinity feed ...

Summers, Edward K

2013-01-01

392

Energy Recovery in Industrial Distillation Processes  

E-print Network

temperatures resulting in significant energy savings. The distillation process will be reviewed as it relates to both vapor recompression and heat pumping techniques and case study examples of these energy recovery methods will be discussed....

Paul, D. B.

1983-01-01

393

Distillation modeling for a uranium refining process  

SciTech Connect

As part of the spent fuel treatment program at Argonne National Laboratory, a vacuum distillation process is being employed for the recovery of uranium following an electrorefining process. Distillation of a salt electrolyte, containing a eutectic mixture of lithium and potassium chlorides, from uranium is achieved by a simple batch operation and is termed {open_quotes}cathode processing{close_quotes}. The incremental distillation of electrolyte salt will be modeled by an equilibrium expression and on a molecular basis since the operation is conducted under moderate vacuum conditions. As processing continues, the two models will be compared and analyzed for correlation with actual operating results. Possible factors that may contribute to aberrations from the models include impurities at the vapor-liquid boundary, distillate reflux, anomalous pressure gradients, and mass transport phenomena at the evaporating surface. Ultimately, the purpose of either process model is to enable the parametric optimization of the process.

Westphal, B.R.

1996-03-01

394

7 CFR 58.331 - Starter distillate.  

...Quality Specifications for Raw Material § 58.331 Starter distillate. The refined flavor components when used to flavor butter and related products. It shall be of food grade quality, free of extraneous material and prepared in accordance with...

2014-01-01

395

Absorptive Recycle of Distillation Waste Heat  

E-print Network

condenser operates above ambient temperature, the rejected heat also contains unused availability. By incorporating an absorption heat pump (AHP) into the distillation process, these sources of unused availability can be tapped so as to recycle (and hence...

Erickson, D. C.; Lutz, E. J., Jr.

1982-01-01

396

27 CFR 24.216 - Distilling material.  

Code of Federal Regulations, 2013 CFR

...216 Section 24.216 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE...DEPARTMENT OF THE TREASURY ALCOHOL WINE Production of Other...water desired to facilitate fermentation or distillation. No...

2013-04-01

397

27 CFR 24.216 - Distilling material.  

Code of Federal Regulations, 2012 CFR

27 Alcohol, Tobacco Products and Firearms...24.216 Section 24.216 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU...water desired to facilitate fermentation or distillation. No...

2012-04-01

398

27 CFR 24.216 - Distilling material.  

Code of Federal Regulations, 2010 CFR

27 Alcohol, Tobacco Products and Firearms...24.216 Section 24.216 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU...water desired to facilitate fermentation or distillation. No...

2010-04-01

399

27 CFR 24.216 - Distilling material.  

Code of Federal Regulations, 2011 CFR

27 Alcohol, Tobacco Products and Firearms...24.216 Section 24.216 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU...water desired to facilitate fermentation or distillation. No...

2011-04-01

400

Modeling and simulation of reactive distillation operations  

SciTech Connect

Important aspects related to modeling and simulation of reactive distillation processes are presented. Reactive distillation processes are system specific and are subject to the sensitivity of the model parameters. The sensitive model parameters have been identified as those belonging to the models describing the physical and/or chemical equilibrium of the reactive system. The influence of the sensitive model parameters on simulation/design is highlighted through a systematic analysis of the models typically employed for steady-state and dynamic simulation of reactive distillation operations. For reliable and consistent simulation and design of reactive distillation operations, a necessary first step is a systematic analysis of the model parameter and the design/operational variables. Validated numerical results from test problems involving two reactive systems are presented.

Pilavachi, P.A. [Univ. Libre de Bruxelles, Brussels (Belgium). Faculty of Applied Sciences] [Univ. Libre de Bruxelles, Brussels (Belgium). Faculty of Applied Sciences; Schenk, M.; Perez-Cisneros, E.; Gani, R. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering] [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemical Engineering

1997-08-01

401

Catalytic reactive distillation process development for 1,1 diethoxy butane production from renewable sources.  

PubMed

Some acetals can be produced from renewable resources (bioalcohols) and seem to be good candidates for different applications such as oxygenated diesel additives. In the present case the production of 1,1 diethoxy butane from bioethanol and butanal is presented. Butanal can be obtained from biobutanol following a partial oxidation or a dehydrogenation process. In this paper innovative process development about the synthesis of the mentioned acetal including catalytic reactive distillation experimental and simulation results will be presented and discussed. Katapak SP modules containing Amberlyst 47 resin were used as structured catalytic packings. This reactive system allowed reaching higher conversions than the equilibrium ones at the same temperatures. All the experimental data gathered allowed to tune a simulation model for the reactive distillation operation which showed a fairly good behavior in order to perform initial 1,1 diethoxy butane production process design studies. PMID:20833537

Agirre, I; Barrio, V L; Güemez, B; Cambra, J F; Arias, P L

2011-01-01

402

Use of computers for multicomponent distillation calculations  

E-print Network

LIBRARY 4 A I4 COLLEGE QF TEXAS USE OF COMPUTERS FOB MULTICOMPONENT DISTILLATION CALCULATIONS A Thesis By Samuel Lane Sullivan Jr, Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE January 1959 Major Subject: Chemical Engineering USE OF COMPUTERS FOR NULTICOMPONENT DISTILLATION CALCULATIONS A Thesis By Samuel Lane Sullivan Jr. Approved as to style and content by: Chairman...

Sullivan, Samuel Lane

2012-06-07

403

Multipartite secret key distillation and bound entanglement  

SciTech Connect

Recently it has been shown that quantum cryptography beyond pure entanglement distillation is possible and a paradigm for the associated protocols has been established. Here we systematically generalize the whole paradigm to the multipartite scenario. We provide constructions of new classes of multipartite bound entangled states, i.e., those with underlying twisted Greenberger-Horne-Zeilinger (GHZ) structure and nonzero distillable cryptographic key. We quantitatively estimate the key from below with the help of the privacy squeezing technique.

Augusiak, Remigiusz; Horodecki, Pawel [Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-952 Gdansk (Poland) and ICFO-Institute Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-952 Gdansk (Poland)

2009-10-15

404

Reducing Energy Usage in Extractive Distillation  

E-print Network

, .. ~ REDUCING ENERGY USAGE IN,EXTRACTIVE DISTILLATION A. C. Saxena V. A. Bhandari Polysar Limited Sarnia, Ontario, Canada Abstract Butadiene 1:3 is separated from other C. hydrocarbons by extractive distillation in a sieve plate tower.... Prior to the development work to be described, the pressure in the extraction tower was controlled at a fixed value. The tower pressure-boilup control loop did not behave satisfactorily in the presence of non-condensables which entered with the feed...

Saxena, A. C.; Bhandari, V. A.

405

Sugarcane bagasse as alternative packing material for biofiltration of benzene polluted gaseous streams: a preliminary study  

Microsoft Academic Search

Removal of benzene vapor from gaseous streams was studied in two identically sized lab-scale biofiltration columns: one filled with a mixture of raw sugarcane bagasse and glass beads, and the other one packed with a mixture of ground sugarcane bagasse and glass beads, in the same volume ratio, as filter materials. Separate series of continuous tests were performed, in parallel,

L. Sene; A. Converti; M. G. A. Felipe; M. Zilli

2002-01-01

406

APPLICATION OF ADSORPTION PACKED-BED REACTOR MODEL FOR PHENOL REMOVAL  

Microsoft Academic Search

An application of an adsorption packed-bed reactor model was used to study the efficiency of the removal of phenolic wastes. The m odel equations are a combination of Particle Kinetics and Transport Kinetics. The mo del predicts the relations between sorbate concentration and flow rate as variables wi th column depth at any time. The model was verified for Granular

M. T. Sorour; F. Abdelrasoul; W. A. Ibrahim

407

Cylinder valve packing nut studies  

SciTech Connect

The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

1991-12-31

408

The current revolution in column technology: how it began, where is it going?  

PubMed

This work revisits the exceptionally rapid evolution of the technology of chromatographic columns and the important progress in speed of analysis and resolution power that was achieved over the last ten years. Whereas columns packed with 10 and 5 ?m fully porous particles dominated the field for nearly thirty years (1975-2000), it took barely six years to see the commercialization of monolithic silica rods (2000), their raise to fame and decay to oblivion, the development of finer fully porous particles with size down to 1.7 ?m (2006), and of sub-3 ?m superficially porous particles (2006). Analysis times and plate heights delivered by columns packed with these recent packing materials have then been improved by more than one order of magnitude in this short period of time. This progress has rendered practically obsolete the age-old design of LC instruments. For low molecular weight compounds, analysts can now achieve peak capacities of 40 peaks in about 15s with a hold-up time of the order of 1.5s , in gradient elution, by operating columns packed with sub-3 ?m shell particles at elevated temperatures, provided that they use optimized high pressure liquid chromatographs. This is the ultimate limit allowed by modern instruments, which have an extra-column band broadening contribution of 7 ?L² at 4.0 mL/min and data acquisition rate of 160 Hz. The best 2.1 mm × 50 mm narrow-bore columns packed with 1.7 ?m silica core-shell particles provide peaks that have a variance of 2.1 ?L² for k=1. Finally, this work discusses possible ways to accelerate separations and, in the same time perform these separations at the same level of efficiency as they have today. It seems possible to pack columns with smaller particles, probably down to 1 ?m and operate them with current vHPLC equipments for separations of biochemicals. Analyses of low molecular weight compounds will require new micro-HPLC systems able to operate 1mm I.D. columns at pressures up to 5 kbar, which would eliminate the heat friction problems, and providing extra-column band broadening contributions smaller than 0.1 ?L². Alternatively, a new generation of vHPLC systems with minimal extra-column contributions of less than 0.5 ?L² could run 2.1mm I.D. columns if these latter were to be packed with high heat conductivity materials such as core-shell particles made with an alumina or gold core. PMID:21872874

Gritti, Fabrice; Guiochon, Georges

2012-03-01

409

Key Distillation and the Secret-Bit Fraction  

Microsoft Academic Search

Abstract— This paper considers the distillation of secret bits from partially secret noisy correlations, PABE, shared between two honest parties and an eavesdropper. In the usual scenario the distillation procedure consists of joint operations on,an arbitrarily large number of copies of the distribution (PABE) 1\\/2 then PABE is distillable, thus providing a sufficient condition for distillability. A simple express ion

Nick S. Jones; Lluis Masanes

2008-01-01

410

EASY AND RAPID ESTIMATION OF ENVIRONMENTAL TRITIUM WITH EICHROM COLUMN AND LSC MEASUREMENT  

Microsoft Academic Search

We investigated the capabilities of tritium columns from Eichrom as an effective, easy, and less expensive method for tritium determination by liquid scintillation (LS) counter. The described procedure was compared with the one presented in ISO 9698 (International Organization for Standardization (ISO) 1989) for routine control purposes. The standard distillation method is time consuming and requires significant effort to eliminate

Z Tosheva; A Kies; P Letissier; M Langer

411

Liquid chromatographic determination of scopoletin in hydroalcoholic extract of oak wood and in matured distilled alcoholic beverages.  

PubMed

A liquid chromatographic (LC) method is described for determination of the coumarins esculin, umbelliferone, scopoletin, and 4-methyl umbelliferone in hydroalcoholic extracts of oak wood and in matured distilled alcoholic beverages. Samples were injected directly into the LC column (30 cm, 5 micron C18) and detected by fluorescence detector. Under these experimental conditions, only scopoletin (detection limit, 200 pg) was found in hydroalcoholic oak wood extracts and in spirits matured in oak wood. Applications of this method to spirits distilled from wine, grain, and sugar cane aged in oak barrels showed that amounts varied from 0.026 to 1.57 ppm. PMID:3391951

Puech, J L; Moutounet, M

1988-01-01

412

Ecology and Energy Action Pack.  

ERIC Educational Resources Information Center

One of five McDonald's Action Packs, these elementary school-level instructional materials are for use as an introduction to existing units of study, supplements to a textbook, or a source of special projects for environmental education. Contents include these six units: Make Your Own Ecology Mini-spinner, Let's Look at a Food Chain, Drip the…

McDonald's Corp., Oak Brook, IL.

413

Teflon-packed flexible joint  

NASA Technical Reports Server (NTRS)

Teflon-packed flexible joint separates the movement of the shaker from the liquid nitrogen hose during the ground testing of cryogenic zero-g equipment. The joint allows the hose to lie on the floor in a stationary position as the shaker moves back and forth, thus, the hose is not subject to violent motion.

Belmont, G. E.

1969-01-01

414

Loco Beans ClassPack  

NSDL National Science Digital Library

Using More Picture-Perfect Science Lessons: Using Children's Books to Guide Inquiry, K-4 in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatche

2010-04-22

415

Mirror, Mirror ClassPack  

NSDL National Science Digital Library

Using More Picture-Perfect Science Lessons: Using Children's Books to Guide Inquiry, K-4 in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatche

2010-04-25

416

Roller Coasters ClassPack  

NSDL National Science Digital Library

Using More Picture-Perfect Science Lessons: Using Children's Books to Guide Inquiry, K-4 in your classroom is easier than ever! NSTA's ClassPacks, each sufficient for a class of 28 students, are lesson-specific collections of materials--an unmatche

2010-04-25

417

Vendors for Hero Pack Items  

E-print Network

Program (603) 225-1215 Wing Family Program (603) 430-3545 Operation: Military Kids is a partnership)? When National Guard, Reserve, and other military families living in civilian communities become. Feel free to use either of these resources and/or your own sources for Hero Pack contents. Military

New Hampshire, University of

418

Wire and Packing Tape Sandwiches  

ERIC Educational Resources Information Center

In this article, the author describes how students can combine craft wire with clear packing tape to create a two-dimensional design that can be bent and twisted to create a three-dimensional form. Students sandwich wire designs between two layers of tape. (Contains 1 online resource.)

Rabinowitz, Sandy

2009-01-01

419

The packing factor Animesh Das  

E-print Network

et al. 2005, Reyes and Iglesia 1991). Deformable objects (for example foam) can generate even denser (Ã?berg 1996a, 1996b, Alshibli and El-Saidany 2001). Figure 3: Foams can generate even denser packing. #12. E., The laws of proportioning concrete, Transactions of ASCE, ASCE, Vol. 59, 1907, pp.67

Das, Animesh

420

Eruption column physics  

SciTech Connect

In this paper the author focuses on the fluid dynamics of large-scale eruption columns. The dynamics of these columns are rooted in multiphase flow phenomena, so a major part of the paper sets up a foundation on that topic that allows one to quickly assess the inherent assumptions made in various theoretical and experimental approaches. The first part is centered on a set of complex differential equations that describe eruption columns, but the focus is on a general understanding of important physical processes rather than on the mathematics. The author discusses briefly the relative merits and weaknesses of different approaches, emphasizing that the largest advances in understanding are made by combining them. He then focuses on dynamics of steady eruption columns and then on transient phenomena. Finally he briefly reviews the effects of varying behavior of the ambient medium through which an eruption column moves. These final sections will emphasize concepts and a qualitative understanding of eruption dynamics. This paper relies on principles of continuum mechanics and transport processes but does not go into detail on the development of those principles. 36 refs., 36 figs., 3 tabs.

Valentine, G.A.

1997-03-01

421

Continuous-flow metal biosorption in a regenerable Sargassum column  

Microsoft Academic Search

Metal biosorption behavior of raw seaweed S. filipendula in ten consecutive sorption–desorption cycles has been investigated in a packed-bed flow-through column during a continuous removal of copper from a 35mg\\/L aqueous solution at pH 5. The elutant used was a 1% (w\\/v) CaCl2\\/HCl-solution at pH 3. The sorption and desorption was carried out for an average of 85 and 15h,

B. Volesky; J. Weber; J. M. Park

2003-01-01

422

Distillation of Multicomponent Mixtures of Higher Aliphatic Acids in Thermally Coupled Distillation Systems  

Microsoft Academic Search

A method is proposed to calculate the characteristics of distillation of multicomponent mixtures of higher aliphatic acids in distillation systems with reversible mixing of flows and coupled heat flows. The method is based on the use of the Underwood equations and the Thiele–Geddes method for independently determining the concentrations. Application of the method is illustrated by the example of calculating

V. A. Plesovskikh; A. A. Bezdenezhnykh

2003-01-01

423

Evaluation of full-scale carbon dioxide stripping columns in a coldwater recirculating system  

Microsoft Academic Search

The objective of this research was to evaluate the dissolved carbon dioxide stripping efficiency of two types of 1-m tall structured plastic packing (tubular NORPAC and structured block CF-3000 Accu-Pac media) that were placed separately in two full-scale forced-ventilation cascade columns that were located within a coldwater recirculating aquaculture system at the Freshwater Institute. These two structured packing types were

Steven T. Summerfelt; John Davidson; Thomas Waldrop

2003-01-01

424

Study of radial compression high-performance liquid chromatographic columns for preparative chromatography  

Microsoft Academic Search

The operating characteristics and efficiency of a preparative-scale, radial compression chromatograph are studied. Two commercial C18 silica packings are used, one irregular and one spherical and monodispersed. For each packing, the relationship between mobile phase flow-rate, column backpressure, and radial compression pressure is determined. A model is proposed to explain this relationship and determine the radial compression pressure needed to

David P. Gervais; W. Scott Laughinghouse; Giorgio Carta

1995-01-01

425

Comparison of Advanced Distillation Control Methods, Final Technical Report  

SciTech Connect

Detailed dynamic simulations of three industrial distillation columns (a propylene/propane splitter, a xylene/toluene column, and a depropanizer) have been used to evaluate configuration selections for single-ended and dual-composition control, as well as to compare conventional and advanced control approaches. In addition, a simulator of a main fractionator was used to compare the control performance of conventional and advanced control. For each case considered, the controllers were tuned by using setpoint changes and tested using feed composition upsets. Proportional Integral (PI) control performance was used to evaluate the configuration selection problem. For single ended control, the energy balance configuration was found to yield the best performance. For dual composition control, nine configurations were considered. It was determined that the use of dynamic simulations is required in order to identify the optimum configuration from among the nine possible choices. The optimum configurations were used to evaluate the relative control performance of conventional PI controllers, MPC (Model Predictive Control), PMBC (Process Model-Based Control), and ANN (Artificial Neural Networks) control. It was determined that MPC works best when one product is much more important than the other, while PI was superior when both products were equally important. PMBC and ANN were not found to offer significant advantages over PI and MPC. MPC was found to outperform conventional PI control for the main fractionator. MPC was applied to three industrial columns: one at Phillips Petroleum and two at Union Carbide. In each case, MPC was found to significantly outperform PI controls. The major advantage of the MPC controller is its ability to effectively handle a complex set of constraints and control objectives.

Dr. James B. Riggs

2000-11-30

426

Optimal thermodynamic approximation to reversible distillation by means of interheaters and intercoolers  

SciTech Connect

The purpose of this paper is to deal with the problem of heat and power integration on one side and the problem of minimizing heat exchange areas on the other side, in both conventional and nonconventional distillation columns. The authors consider the limiting case of columns operating at minimum reflux. The appropriate objective functions that one must consider are the entropy production rate and the total heat exchange area, respectively. This is done by means of optimal placement of a given number of interheaters (IHs) and intercoolers (ICs) in stripping and rectifying sections, respectively. To solve these problems, an appropriate thermodynamic model for both conventional and nonconventional distillative columns is formally presented. This model allows one to formulate an optimization problem involving thermodynamically reversible profiles in stripping and rectifying sections of the columns. This approach differs from others previously reported in that multiple reversible profiles were identified for each section of the column which give rise to lower and upper bounds for the objective function of the minimization problem. In other words, the authors obtain two solutions for each column section: the first is a nonoptimal feasible one, and the second is an optimal but not necessarily feasible one. Finally, the comparison of this approach with a method based on pseudobinary reversible profiles is carried out. Optimizing with this curve, solutions will be generated with objective function values between the lower and upper bounds. Therefore, care would be taken in using a pseudobinary pinch point curve for the placement of intermediate heat-exchanger units especially when the difference between the upper and lower bounds for the objective function values is relatively great.

Aguirre, P.; Espinosa, J.; Tarifa, E.; Scenna, N. [CONICET, Santa Fe (Argentina)] [CONICET, Santa Fe (Argentina)

1997-11-01

427

High pressure humidification columns: Design equations, algorithm, and computer code  

SciTech Connect

This report describes the detailed development of a computer model to simulate the humidification of an air stream in contact with a water stream in a countercurrent, packed tower, humidification column. The computer model has been developed as a user model for the Advanced System for Process Engineering (ASPEN) simulator. This was done to utilize the powerful ASPEN flash algorithms as well as to provide ease of use when using ASPEN to model systems containing humidification columns. The model can easily be modified for stand-alone use by incorporating any standard algorithm for performing flash calculations. The model was primarily developed to analyze Humid Air Turbine (HAT) power cycles; however, it can be used for any application that involves a humidifier or saturator. The solution is based on a multiple stage model of a packed column which incorporates mass and energy, balances, mass transfer and heat transfer rate expressions, the Lewis relation and a thermodynamic equilibrium model for the air-water system. The inlet air properties, inlet water properties and a measure of the mass transfer and heat transfer which occur in the column are the only required input parameters to the model. Several example problems are provided to illustrate the algorithm`s ability to generate the temperature of the water, flow rate of the water, temperature of the air, flow rate of the air and humidity of the air as a function of height in the column. The algorithm can be used to model any high-pressure air humidification column operating at pressures up to 50 atm. This discussion includes descriptions of various humidification processes, detailed derivations of the relevant expressions, and methods of incorporating these equations into a computer model for a humidification column.

Enick, R.M. [Pittsburgh Univ., PA (United States). Dept. of Chemical and Petroleum Engineering; Klara, S.M. [USDOE Pittsburgh Energy Technology Center, PA (United States); Marano, J.J. [Burns and Roe Services Corp., Pittsburgh, PA (United States)

1994-07-01

428

7 CFR 51.1311 - Packing.  

Code of Federal Regulations, 2010 CFR

...tightly packed. All packages shall be well filled but the contents shall not show excessive or unnecessary bruising because of overfilled packages. (c) Pears packed in boxes shall be arranged in containers according to the approved and recognized...

2010-01-01

429

7 CFR 51.1270 - Packing.  

Code of Federal Regulations, 2010 CFR

...tightly packed. All packages shall be well filled but the contents shall not show excessive or unnecessary bruising because of overfilled packages. (c) Pears packed in boxes shall be arranged in containers according to the approved and recognized...

2010-01-01

430

7 CFR 984.15 - Pack.  

Code of Federal Regulations, 2010 CFR

...AGRICULTURE WALNUTS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 984.15 Pack. Pack means to bleach, clean, grade, shell or otherwise prepare walnuts for market as inshell or shelled walnuts. [73 FR 11337, Mar....

2010-01-01

431

7 CFR 917.13 - Pack.  

Code of Federal Regulations, 2010 CFR

...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 917.13 Pack. Pack means the specific...

2010-01-01

432

7 CFR 917.13 - Pack.  

Code of Federal Regulations, 2011 CFR

...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Order Regulating Handling Definitions § 917.13 Pack. Pack means the specific...

2011-01-01

433

7 CFR 906.10 - Pack.  

Code of Federal Regulations, 2010 CFR

...Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ORANGES AND GRAPEFRUIT GROWN IN LOWER RIO GRANDE VALLEY IN TEXAS Order Regulating Handling Definitions § 906.10 Pack. Pack means the specific grade,...

2010-01-01

434

7 CFR 966.11 - Pack.  

Code of Federal Regulations, 2012 CFR

...Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2012-01-01

435

7 CFR 966.11 - Pack.  

...NUTS), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2014-01-01

436

7 CFR 966.11 - Pack.  

Code of Federal Regulations, 2011 CFR

...Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2011-01-01

437

7 CFR 966.11 - Pack.  

Code of Federal Regulations, 2010 CFR

...Nuts), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2010-01-01

438

7 CFR 966.11 - Pack.  

Code of Federal Regulations, 2013 CFR

...NUTS), DEPARTMENT OF AGRICULTURE TOMATOES GROWN IN FLORIDA Order Regulating... Pack means any of the packs of tomatoes as defined and set forth in the United States Standards for Fresh Tomatoes issued by the United States...

2013-01-01

439

Fundamental Studies on Two-Phase Gas-Liquid Flows Through Packed Beds in Microgravity  

NASA Astrophysics Data System (ADS)

In the typical operation of a packed-bed reactor, gas and liquid flow simultaneously through a fixed bed of solid particles. Depending on the application, the particles can be of various shapes and sizes and provide for intimate contact and high rates of transport between the phases needed to sustain chemical or biological reactions. The packing may also serve as either a catalyst or as a support for growing biological material. NASA has flown two of these packed-bed systems in a microgravity environment with limited or no success. The goal of this research is to develop models (with scale-up capability) needed for the design of the physicochemical equipment to carry out these unit operations in microgravity. New insight will also lead to improvements in normal gravity operations. Our initial experiment was flown using an existing KC-135 two-phase flow rig with a modified test section. The test section is a clear polycarbonate rectangular column with a depth of 2.54 cm, a width of 5.08 cm, and 60 cm long. The column was randomly packed with spherical glass beads by slowly dropping the beads into the bed. Even though care was taken in handling the column after it was filled with packing, the alternating high and low gravity cycles with each parabola created a slightly tighter packed bed than is typically reported for this type. By the usual method of comparing the weight difference of a completely dry column versus a column filled with water, the void fraction was found to be .345 for both sizes of beads used. Five flush mounted differential pressure transducers are spaced at even intervals with the first location 4 cm from the inlet port and the subsequent pressure transducers spaced at 13 cm intervals along the column. Differential pressure data was acquired at 1000 Hz to adequately observe pulse formation and characteristics. Visual images of the flow were recorded using a high-speed SVHS system at 500 frames per second. Over 250 different test conditions were evaluated along with a companion set of tests in normal gravity. The flow rates, fluid properties and packing properties were selected to provide a range of several orders-of-magnitude for the important dimensionless parameters. Additional information is included in the original extended abstract.

Balakotaiah, Vemuri; McCready, Mark J.; Motil, Brian J.

2002-11-01

440

Fundamental Studies on Two-Phase Gas-Liquid Flows Through Packed Beds in Microgravity  

NASA Technical Reports Server (NTRS)

In the typical operation of a packed-bed reactor, gas and liquid flow simultaneously through a fixed bed of solid particles. Depending on the application, the particles can be of various shapes and sizes and provide for intimate contact and high rates of transport between the phases needed to sustain chemical or biological reactions. The packing may also serve as either a catalyst or as a support for growing biological material. NASA has flown two of these packed-bed systems in a microgravity environment with limited or no success. The goal of this research is to develop models (with scale-up capability) needed for the design of the physicochemical equipment to carry out these unit operations in microgravity. New insight will also lead to improvements in normal gravity operations. Our initial experiment was flown using an existing KC-135 two-phase flow rig with a modified test section. The test section is a clear polycarbonate rectangular column with a depth of 2.54 cm, a width of 5.08 cm, and 60 cm long. The column was randomly packed with spherical glass beads by slowly dropping the beads into the bed. Even though care was taken in handling the column after it was filled with packing, the alternating high and low gravity cycles with each parabola created a slightly tighter packed bed than is typically reported for this type. By the usual method of comparing the weight difference of a completely dry column versus a column filled with water, the void fraction was found to be .345 for both sizes of beads used. Five flush mounted differential pressure transducers are spaced at even intervals with the first location 4 cm from the inlet port and the subsequent pressure transducers spaced at 13 cm intervals along the column. Differential pressure data was acquired at 1000 Hz to adequately observe pulse formation and characteristics. Visual images of the flow were recorded using a high-speed SVHS system at 500 frames per second. Over 250 different test conditions were evaluated along with a companion set of tests in normal gravity. The flow rates, fluid properties and packing properties were selected to provide a range of several orders-of-magnitude for the important dimensionless parameters. Additional information is included in the original extended abstract.

Balakotaiah, Vemuri; McCready, Mark J.; Motil, Brian J.

2002-01-01

441

Ecology of southern ocean pack ice.  

PubMed

Around Antarctica the annual five-fold growth and decay of sea ice is the most prominent physical process and has a profound impact on marine life there. In winter the pack ice canopy extends to cover almost 20 million square kilometres--some 8% of the southern hemisphere and an area larger than the Antarctic continent itself (13.2 million square kilometres)--and is one of the largest, most dynamic ecosystems on earth. Biological activity is associated with all physical components of the sea-ice system: the sea-ice surface; the internal sea-ice matrix and brine channel system; the underside of sea ice and the waters in the vicinity of sea ice that are modified by the presence of sea ice. Microbial and microalgal communities proliferate on and within sea ice and are grazed by a wide range of proto- and macrozooplankton that inhabit the sea ice in large concentrations. Grazing organisms also exploit biogenic material released from the sea ice at ice break-up or melt. Although rates of primary production in the underlying water column are often low because of shading by sea-ice cover, sea ice itself forms a substratum that provides standing stocks of bacteria, algae and grazers significantly higher than those in ice-free areas. Decay of sea ice in summer releases particulate and dissolved organic matter to the water column, playing a major role in biogeochemical cycling as well as seeding water column phytoplankton blooms. Numerous zooplankton species graze sea-ice algae, benefiting additionally because the overlying sea-ice ceiling provides a refuge from surface predators. Sea ice is an important nursery habitat for Antarctic krill, the pivotal species in the Southern Ocean marine ecosystem. Some deep-water fish migrate to shallow depths beneath sea ice to exploit the elevated concentrations of some zooplankton there. The increased secondary production associated with pack ice and the sea-ice edge is exploited by many higher predators, with seals, seabirds and whales aggregating there. As a result, much of the Southern Ocean pelagic whaling was concentrated at the edge of the marginal ice zone. The extent and duration of sea ice fluctuate periodically under the influence of global climatic phenomena including the El Niño Southern Oscillation. Life cycles of some associated species may reflect this periodicity. With evidence for climatic warming in some regions of Antarctica, there is concern that ecosystem change may be induced by changes in sea-ice extent. The relative abundance of krill and salps appears to change interannually with sea-ice extent, and in warm years, when salps proliferate, krill are scarce and dependent predators suffer severely. Further research on the Southern Ocean sea-ice system is required, not only to further our basic understanding of the ecology, but also to provide ecosystem managers with the information necessary for the development of strategies in response to short- and medium-term environmental changes in Antarctica. Technological advances are delivering new sampling platforms such as autonomous underwater vehicles that are improving vastly our ability to sample the Antarctic under sea-ice environment. Data from such platforms will enhance greatly our understanding of the globally important Southern Ocean sea-ice ecosystem. PMID:12154613

Brierley, Andrew S; Thomas, David N

2002-01-01

442

On the kinetics of pack aluminization  

NASA Technical Reports Server (NTRS)

A theory of pack aluminization has been formulated by combining gaseous and solid-state diffusion rates. This theory relates the surface composition of the coating and therefore, in principle, the phase morphology and the growth rate of the coating, to pack operating parameters such as pack aluminum density, type of activator, temperature and others. Experimental data on the aluminization of unalloyed nickel in pure aluminum packs obtained to date are in good agreement with the predictions of the theory.

Gupta, B. K.; Sarkhel, A. K.; Seigle, L. L.

1975-01-01

443

Columns in Clay  

ERIC Educational Resources Information Center

This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

Leenhouts, Robin

2010-01-01

444

Efficiency of supercritical fluid chromatography columns in different thermal environments.  

PubMed

The efficiency of a packed column eluted with supercritical carbon dioxide at 323K and outlet pressures from 90 to 150bar was studied with the column in two different thermal environments. The 150mm×2.0mm ID stainless steel column was packed with spherical 5-?m porous silica particles with a covalently bonded nonpolar stationary phase, and the test solutes were normal alkanes. When operated in a convective air bath the column exhibited severe efficiency losses when its outlet pressure was below 120bar. The efficiency of the same column enclosed in a shell made of foam insulation was restored at low outlet pressures down to 100bar. The van Deemter plots showed an abnormal dependence of the plate height (HETP) on the flow rate at low outlet pressures, exhibiting a maximum in the HETP at flow rates around 1mL/min and a 20-bar pressure drop. The large efficiency losses at low outlet pressures are due to radial temperature gradients associated with enthalpic expansion and cooling of the mobile phase. The separations were simulated by a numerical model that accounts for axial and radial gradients in the temperature and density along the column. The abnormal van Deemter plots arise from competing processes affecting the radial distribution of the solute migration velocity along the column. The negative impact on efficiency is greatest when the density profile of the mobile phase along the column is close to the critical isopycnic line. The efficiency improves at increased flow rates because of increased cooling at larger pressure drops and increased density along the entire length of the column. The model predicts the unusual trends in the van Deemter plots, but the calculated results at low outlet pressures are strongly influenced by small variations in the porosity distribution in the column, limiting the accuracy of the predicted HETP values. In spite of these difficulties, the model has enabled a detailed analysis of the effects of temperature, pressure and flow rate on the thermal properties of the mobile phase, and their impact on the radial distribution of the solute velocities along the column. This work provides a better appreciation of the factors that cause excess efficiency loss at low outlet pressures, a phenomenon that lacked a convincing explanation for over 40 years. Finally, a simplified form of the model, which ignores the radial gradients, provided accurate results only at the highest outlet pressure. Calculations done by the simplified model are much faster, and it can be recommended for simulation of SFC processes at sufficiently high outlet pressures. PMID:23598158

Kaczmarski, Krzysztof; Poe, Donald P; Tarafder, Abhijit; Guiochon, Georges

2013-05-24

445

Vacuum distillation/vapor filtration water recovery  

NASA Technical Reports Server (NTRS)

The development and evaluation of a vacuum distillation/vapor filtration (VD/VF) water recovery system are considered. As a functional model, the system converts urine and condensates waste water from six men to potable water on a steady-state basis. The system is designed for 180-day operating durations and for function on the ground, on zero-g aircraft, and in orbit. Preparatory tasks are summarized for conducting low gravity tests of a vacuum distillation/vapor filtration system for recovering water from urine.

Honegger, R. J.; Neveril, R. B.; Remus, G. A.

1974-01-01

446

Distillation: Present Status and Future Directions  

E-print Network

it could be useful, and this leads to a discussion of mechanical vapor r.ecompression as appl ied to distillation. Mechanical vapor recompression (MVR) is not a new concept. It is not a product of the 1970s energy crisis. For many years its potential... it could be useful, and this leads to a discussion of mechanical vapor r.ecompression as appl ied to distillation. Mechanical vapor recompression (MVR) is not a new concept. It is not a product of the 1970s energy crisis. For many years its potential...

Fair, J. R.; Humphrey, J. L.

1984-01-01

447

Monolithic silica capillary column extraction of methamphetamine and amphetamine in urine coupled with thin-layer chromatographic detection  

Microsoft Academic Search

A monolithic silica capillary column was first developed in Japan in 2001 as a new tool for better liquid chromatographic\\u000a separation. The column is made of C18-bonded monolithic silica packed into a capillary glass tube (0.20 mm i.d.). In this study, we used this column for solid-phase\\u000a extraction of methamphetamine (MA) and amphetamine (AP) in urine. Chromatographic separation was achieved

Akihiro Nakamoto; Akira Namera; Manami Nishida; Mikio Yashiki; Takako Kuramoto; Yoshiyuki Takei; Masahiro Furuno; Hiroyoshi Minakuchi; Kazuki Nakanishi; Kojiro Kimura

2006-01-01

448

Ant Colony Optimisation for Bin Packing and  

E-print Network

Ant Colony Optimisation for Bin Packing and Cutting Stock Problems Frederick Ducatelle T H E U N I of Informatics University of Edinburgh 2001 #12; Abstract The bin packing and the cutting stock problems are two and evolutionary programming. In this dissertation, I try to solve the bin packing and the cutting stock problem

Ducatelle, Frederick

449

7 CFR 51.1217 - Standard pack.  

Code of Federal Regulations, 2011 CFR

... United States Standards for Grades of Peaches Standard Pack § 51.1217 Standard...Each package shall be packed so that the peaches in the shown face shall be reasonably...the contents of the package. (b) Peaches packed in U.S. Standard bushel...

2011-01-01

450

Characteristics of fluidized-packed beds  

NASA Technical Reports Server (NTRS)

Study of fluidized-packed bed includes investigation of heat transfer, solids-gas mixing, and elutriation characteristics. A fluidized-packed bed is a system involving the fluidization of small particles in the voids of a packed bed of larger nonfluidized particles.

Gabor, J. D.; Mecham, W. J.

1968-01-01

451

Hydrolysis of milk\\/whey lactose by ? galactosidase: A comparative study of stirred batch process and packed bed reactor prepared with calcium alginate entrapped enzyme  

Microsoft Academic Search

Calcium alginate entrapped ? galactosidase preparations were used for the hydrolysis of lactose from solution, milk and whey in batch processes as well as in continuous packed bed columns. The efficiency of columns, containing calcium alginate entrapped soluble and crosslinked concanavalin A complex of ? galactosidase was examined at various flow rates at room temperature 32°C, for the continuous hydrolysis

Toshiba Haider; Qayyum Husain

2009-01-01

452

Preparation and evaluation of molecularly imprinted polymer liquid chromatography column for the separation of Cathine enantiomers  

PubMed Central

In this study molecular imprinting technology was employed to prepare a specific affinity sorbent for the resolution of Cathine, a chiral drug product. The molecularly imprinted polymer (MIP) was prepared by non-covalent molecular imprinting with either (+) or (?)-Cathine (threo-2-amino-1-hydroxy-1-phenyl propane; norpseudoephedrine) as the template. Methacrylic acid and ethylene glycol di-methacrylate were copolymerized in the presence of the template molecule. The bulk polymerization was carried out in chloroform with 2,2?-azobisisobutyronitrile as the initiator, at 5 °C and under UV radiation. The resulting MIP was ground into powders, which were slurry packed into analytical columns. After removal of template molecules, the MIP-packed columns were found to be effective for the resolution of (±)-Cathine racemates. The separation factor for the enantiomers ranged between 1.5 and 2.4 when the column was packed with MIP prepared with (+)-Cathine as the template. A separation factor ranging from 1.6 to 2.9 could be achieved from the column packed with MIP, prepared with (?)-Cathine as the template. Although the separation factor was higher with that previously obtained from reversed-phase column chromatography following derivatization with a chiral agent, elution peaks were broader due to the heterogeneity of binding sites on MIP particles and the possible non-specific interaction. PMID:23960776

Balamurugan, Krishnamoorthy; Gokulakrishnan, Kannan; Prakasam, Tangirala

2011-01-01

453

[Determination of tetrodotoxin in fermentation broth of distiller's yeast by ion chromatography].  

PubMed

A method was developed for the quantitative analysis of tetrodotoxin (TTX) in fermentation broth of distiller's yeast by ion chromatography. After extraction with acetonitrile solution (containing 0.1% phosphoric acid) and purification with an ion-exchange column, the tetrodotoxin was separated by ion chromatography and detected by a ultraviolet-visible (UV-VIS) absorbance detector. The experimental results showed that the tetrodotoxin had a good linearity (r2 = 0.997) in the range of 10 - 100 mg/L and the detection limit (3 of signal-to-noise ratio) was 1.0 mg/L. The average recoveries were between 90% - 103% with a relative standard deviation lower than 4.9%. The analysis of real samples verified the reliability of this method and demonstrated that the ion chromatography can be used for the quantification detection of the tetrodotoxin. The degradation experiment results suggested that distiller's yeast had a remarkable effect on the tetrodotoxin degradation. PMID:21598524

Shu, Jing; Li, Bailin; Ou, Jie

2011-02-01

454

Computation of multicomponent distillation processes by the Newton-Raphson method using an implicit function  

SciTech Connect

A new iterative method is presented for the rigorous simulation of multicomponent distillation processes using the Newton-Raphson method to solve the simultaneous equations, which is characterized by the use of the liquid compositions as the independent variables and analytical equations for evaluating the partial derivatives, with the vapor compositions and temperatures as the dependent variables. The analytical equations for the partial derivatives of the vapor compositions with respect to the liquid compositions are derived, using the implicit-function theorem. The advantages of the method are that a numerical differentiation of the partial derivatives is unnecessary, as is normalization of the liquid compositions. The method has excellent convergence characteristics when applied to 10 typical distillation columns of complicated structure.

Shimizu, K. (Nippon Synthetic Chem. Ind. Co., Ltd., Osaka (Japan)); Sayama, H.; Kameyama, Y.; Suzuki, K. (Okayama Univ. (Japan))

1993-01-01

455

Reducing CO2 emissions and energy consumption of heat-integrated distillation systems.  

PubMed

Distillation systems are energy and power intensive processes and contribute significantly to the greenhouse gases emissions (e.g. carbon dioxide). Reducing CO2 emissions is an absolute necessity and expensive challenge to the chemical process industries in orderto meetthe environmental targets as agreed in the Kyoto Protocol. A simple model for the calculation of CO2 emissions from heat-integrated distillation systems is introduced, considering typical process industry utility devices such as boilers, furnaces, and turbines. Furnaces and turbines consume large quantities of fuels to provide electricity and process heats. As a result, they produce considerable amounts of CO2 gas to the atmosphere. Boilers are necessary to supply steam for heating purposes; besides, they are also significant emissions contributors. The model is used in an optimization-based approach to optimize the process conditions of an existing crude oil atmospheric tower in order to reduce its CO2 emissions and energy demands. It is also applied to generate design options to reduce the emissions from a novel internally heat-integrated distillation column (HIDiC). A gas turbine can be integrated with these distillation systems for larger emissions reduction and further energy savings. Results show that existing crude oil installations can save up to 21% in energy and 22% in emissions, when the process conditions are optimized. Additionally, by integrating a gas turbine, the total emissions can be reduced further by 48%. Internal heat-integrated columns can be a good alternative to conventional heat pump and other energy intensive close boiling mixtures separations. Energy savings can reach up to 100% with respect to reboiler heat requirements. Emissions of these configurations are cut down by up to 83%, compared to conventional units, and by 36%, with respect to heat pump alternatives. Importantly, cost savings and more profit are gained in parallel to emissions minimization. PMID:16190250

Gadalla, Mamdouh A; Olujic, Zarko; Jansens, Peter J; Jobson, Megan; Smith, Robin

2005-09-01

456

A Flexible Moisture Content Probe for Unsaturated Soil Column Experiments  

SciTech Connect

A commercially available soil moisture capacitance probe was modified by replacing rigid electrode traces with non-intrusive, flexible circuit board trace electrodes that can be attached to the interior of soil column walls. This new design minimizes soil packing difficulties and potential bias in flow pathways commonly associated with rigid probe installations in column experiments. Testing showed that the modified probe design provides reproducible output independent of sample bulk density. The electrical conductivity of the pore-water solution, however, affects the probe response. For cases where the specific conductance of the pore-water solution is constant, the probe can be calibrated. The flexible electrodes offer a simple means of minimizing sensor intrusion into laboratory soil columns while providing reproducible voltage output that is a function of moisture content.

E. D. Mattson; K. E. Baker; C. D. Palmer; J. M Svoboda

2006-05-01

457

Removal of water haze from distillate fuel  

SciTech Connect

A method is described for de-hazing distillate fuel which comprises adding to the fuel an organosiloxane having at least one quaternary ammonium substituted siloxane unit having the general formula R/sub a/ZSiO/sub (3-a)/2/ in which a has the value 1 or 2, each R is selected from the group consisting of substituted and unsubstituted hydrocarbon groups having up to 10 carbon atoms, provided that one R may be a hydroxyl group when a has the value 2, Z represents a quaternary ammonum group having the formula R'N/sup +/(R/sup 2/)/sub 3/X/sup -/ linked to the silicon atom of the siloxane unit, in which R' represents a divalent hydrocarbon group linking the silicon and nitrogen atoms, each R/sup 2/ represents an alkyl group having up to 20 carbon atoms and X/sup -/ represents a halogen ion, the distillate fuel containing up to about 0.1 percent by weight of water dispersed therein. The patent also describes a mixture consisting essentially of a distillate fuel and up to about 0.1 percent by weight of water based on the weight of the distillate fuel; with a de-hazing amount of an organosiloxane having at least one quaternary ammonium substituted siloxane unit.

Easton, T.; Thomas, B.

1989-04-04

458

Enzyme mass-transfer coefficient in aqueous two-phase systems using static mixer extraction column  

Microsoft Academic Search

Recent technical advances in aqueous two-phase systems (ATPS) have made this a sound technique for the extraction of biomacromolecules. The extraction of !-amylase was investigated using aqueous two-phase systems formed by sodium sulphate-polyethylene glycol (PEG) in water in a 47-mm inner diameter spray column packed with three types of static mixers. The effects of dispersed-phase flow rate, phase composition, column

K. Rostami; M. Alamshahi

2002-01-01

459

Pressurized capillary electrochromatographic assay of trimethoprim impurities using 1 ?m particle-based columns  

Microsoft Academic Search

One micrometre silica particles, derivatized with C18, were electrokinetically packed into a 75-?m-i.d. capillary. The resulting column was evaluated for the separation of trimethoprim (TMP) and its impurities using pressurized capillary electrochromatography (pCEC), starting from a capillary liquid chromatographic (CLC) separation. These samples require gradient elution when separated by high performance liquid chromatography (HPLC), but with the new columns isocratic

Qi Shu Qu; Debby Mangelings; Fei Shen; Xiao Ya Hu; Chao Yan; Yu Kui Zhang; Yvan Vander Heyden

2007-01-01

460

Short-Fiber Chromatography Columns: Potential for Process-Scale Bioseparations  

Microsoft Academic Search

Chromatographic supports with short-fiber geometry have been evaluated for process-scale applications. Using a prototype silica-based ion-exchange fiber and bovine serum albumin as the model biomolecule, a comparison of the throughput characteristics of fiber columns with those of conventional columns (spherical packing) has been made. The comparison accounts for the influences of pressure drop, adsorption thermodynamics, and mass transfer. It has

Chad A. Farschman; John B. Manos; Neville G. Pinto

1995-01-01

461

Adhesive Loose Packings of Small Particles  

E-print Network

We explore adhesive loose packings of dry small spherical particles of micrometer size using 3D discrete-element simulations with adhesive contact mechanics. A dimensionless adhesion parameter ($Ad$) successfully combines the effects of particle velocities, sizes and the work of adhesion, identifying a universal regime of adhesive packings for $Ad>1$. The structural properties of the packings in this regime are well described by an ensemble approach based on a coarse-grained volume function that includes correlations between bulk and contact spheres. Our theoretical and numerical results predict: (i) An equation of state for adhesive loose packings that appears as a continuation from the frictionless random close packing (RCP) point in the jamming phase diagram; (ii) The existence of a maximal loose packing point at the coordination number $Z=2$ and packing fraction $\\phi=1/2^{3}$. Our results highlight that adhesion leads to a universal packing regime at packing fractions much smaller than the random loose packing, which can be described within a statistical mechanical framework. We present a general phase diagram of jammed matter comprising frictionless, frictional, adhesive as well as non-spherical particles, providing a classification of packings in terms of their continuation from the spherical frictionless RCP.

Wenwei Liu; Shuiqing Li; Adrian Baule; Hernán A. Makse

2014-10-08

462

Thermal analysis for ion-exchange column system  

SciTech Connect

Models have been developed to simulate the thermal characteristics of Crystalline Silico-titanate (CST) ion exchange media fully loaded with radioactive cesium in a column configuration and distributed within a waste storage tank. This work was conducted to support the Small Column Ion Exchange (SCIX) program which is focused on processing dissolved, high-sodium salt waste for the removal of specific radionuclides (including Cs-137, Sr-90, and actinides) within a High Level Waste (HLW) storage tank at the Savannah River Site. A two-dimensional computational modeling approach for the in-column ion-exchange domain was taken to include conservative, bounding estimates for key parameters such that the results would provide the maximum centerline temperatures achievable under the design configurations using a feed composition known to promote high cesium loading on CST. A primary objective of these calculations was to estimate temperature distributions across packed CST beds immersed in waste supernate or filled with dry air under various accident scenarios. Accident scenarios evaluated included loss of salt solution flow through the bed, inadvertent column drainage, and loss of active cooling in the column. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature. (authors)

Lee, S. Y.; King, W. D. [Savannah River National Laboratory, Savannah River Site, Aiken, SC 29808 (United States)

2012-07-01

463

Using Artificial Neural networks for the modelling of a distillation column  

Microsoft Academic Search

The main aim of this paper is to establish a reliable model both for the steady-state and unsteady-state regime s of a nonlinear process. The use of this model should reflect the true behavior of the process under its normal operating conditions and allow distinguishing a normal mode from an abnormal one. In order to obtain this reliable model for

Yahya Chetouani

2007-01-01

464

Solution of Multicomponent distillation problems for conventional and complex columns at unsteady state operation  

E-print Network

of convergence (7). At the end of each trial, the system was placed in component-material balance subject to the restraints of the specifications by the use of the Newton-Raphson method (6). The implicit method (1, 2, 10) has been thoroughly investigated...-4)) is given by ? 1 N+1 FX. +( )(F X. -d. -b. )+ ? . ' u, . I-'u o o o o 1 ). o i '4 i i i nest =0 'i - D 10 1+ e (b, /d, ) 1+ + ? 3 (u. . /d. ) -I 1 t ca &at u8t . ji i ca j=0 (3-gb) Equations (3 4) may be solved by use of the Newton-Raphson method...

Pendon, Gregorio Parrenas

2012-06-07

465

Optimal control of distillation column using Non-Dominated Sorting Genetic Algorithm-II  

Microsoft Academic Search

Many control problems involve simultaneous optimization of multiple performance measures that are often non-commensurable and competing with each other. The presence of multiple objectives in a problem usually gives rise to one set of optimal solutions, largely known as Pareto-optimal solutions. In this paper, the Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) has been successfully applied to optimization of dynamic state of

Alireza Behroozsarand; Sirous Shafiei

2011-01-01

466

Improved micromachined column design and fluidic interconnects for programmed high-temperature gas chromatography separations.  

PubMed

This work focuses on the development and experimental evaluation of micromachined chromatographic columns for use in a commercial gas chromatography (GC) system. A vespel/graphite ferrule based compression sealing technique is presented using which leak-proof fluidic interconnection between the inlet tubing and the microchannel was achieved. This sealing technique enabled separation at temperatures up to 350°C on a ?GC column. This paper reports the first high-temperature separations in microfabricated chromatographic columns at these temperatures. A 2m microfabricated column using a double Archimedean spiral design with a square cross-section of 100?m×100?m has been developed using silicon microfabrication techniques. The microfabricated column was benchmarked against a 2m 100?m diameter commercial column and the performance between the two columns was evaluated in tests performed under identical conditions. High temperature separations of simulated distillation (ASTM2887) and polycyclic aromatic hydrocarbons (EPA8310) were performed using the ?GC column in temperature programmed mode. The demonstrated ?GC column along with the high temperature fixture offers one more solution toward potentially realizing a portable ?GC device for the detection of semi-volatile environmental pollutants and explosives without the thermal limitations reported to date with ?GC columns using epoxy based interconnect technology. PMID:24866564

Gaddes, David; Westland, Jessica; Dorman, Frank L; Tadigadapa, Srinivas

2014-07-01

467

Latching mechanism for deployable/re-stowable columns useful in satellite construction  

NASA Technical Reports Server (NTRS)

A column longeron latch assembly provides the securing mechanism for the deployable, telescoping column of a hoop/column antenna. The column is an open lattice structure with three longerons disposed 120 deg apart as the principle load bearing member. The column is deployed from a pair of eleven nested bays disposed on opposite sides of a center section under the influence of a motor-cable-pulley system. The longeron latch is a four bar linkage mechanism using the over-center principle for automatically locking the longeron sections into position during deployment. The latch is unlocked when the antenna is to be restowed. A spring pack disposed in the end of each longeron serves to absorb stress forces on the deployed column through the cam head piston and abutting latch from an adjacent longeron.

Ahl, E. L., Jr. (inventor)

1986-01-01

468

40 CFR 1065.703 - Distillate diesel fuel.  

Code of Federal Regulations, 2010 CFR

...1065.703 Distillate diesel fuel. (a) Distillate diesel fuels for testing must be clean and bright, with pour and cloud points adequate for proper engine operation. (b) There are three grades of #2 diesel fuel specified for use as...

2010-07-01

469

40 CFR 1065.703 - Distillate diesel fuel.  

Code of Federal Regulations, 2011 CFR

...1065.703 Distillate diesel fuel. (a) Distillate diesel fuels for testing must be clean and bright, with pour and cloud points adequate for proper engine operation. (b) There are three grades of #2 diesel fuel specified for use as...

2011-07-01

470

40 CFR 1065.703 - Distillate diesel fuel.  

Code of Federal Regulations, 2013 CFR

...1065.703 Distillate diesel fuel. (a) Distillate diesel fuels for testing must be clean and bright, with pour and cloud points adequate for proper engine operation. (b) There are three grades of #2 diesel fuel specified for use as...

2013-07-01

471

27 CFR 19.669 - Distilled spirits taxes.  

... ALCOHOL DISTILLED SPIRITS PLANTS Distilled Spirits for Fuel Use Liability for Taxes § 19...free of tax from an alcohol fuel plant if the spirits are withdrawn exclusively for fuel use in accordance with this...

2014-04-01

472

27 CFR 19.651 - Liability for distilled spirits tax.  

Code of Federal Regulations, 2013 CFR

27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Liability for distilled spirits tax...651 Alcohol, Tobacco Products and Firearms ALCOHOL AND...by the Vaporizing Process Liability for Distilled Spirits Tax...

2013-04-01

473

27 CFR 19.651 - Liability for distilled spirits tax.  

Code of Federal Regulations, 2011 CFR

27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Liability for distilled spirits tax...651 Alcohol, Tobacco Products and Firearms ALCOHOL AND...by the Vaporizing Process Liability for Distilled Spirits Tax...

2011-04-01

474

27 CFR 19.651 - Liability for distilled spirits tax.  

27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Liability for distilled spirits tax...651 Alcohol, Tobacco Products and Firearms ALCOHOL AND...by the Vaporizing Process Liability fo