Deposition of Particles from Non-aqueous Suspensions in an Impinging Jet

Patricia L Stelmack1, Jacob H Masliyah1, Jan Czarnecki2 and Murray R Gray*1

1. Department of Chemical and Materials Engineering, University of Alberta,

Edmonton, AB T6G 2G6

2. Syncrude Canada Ltd. 9421-17 Ave., Edmonton, AB T6N 1H4

March, 1999

* Author for correspondence:

Murray R Gray Department of Chemical and Materials Engineering University of Alberta Edmonton, Alberta. T6G 2G6 FAX: (403) 492-7965 E-mail: murray.gray@ualberta.ca

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Abstract

The purpose of this study was to define the mechanism of particle deposition on collectors in

non-aqueous media, in order to understand filtration of fine particles in packed-bed reactors for

hydrotreating of petroleum fractions. A model suspension of either carbon black or hydrophobic

kaolin particles in kerosene was used in the well-defined flow field provided by an impinging jet.

The coverage of a horizontal glass collector surface was determined with time by microscopy.

Deposition of particles was measured in pure kerosene, and with the addition of phenol or

quinoline to simulate the polar compounds found in the feed streams to hydrotreating reactors.

Deposition increased when small amounts of phenol or quinoline were present, and kaolin

particles deposited much more slowly than carbon black, but the properties of the medium were

unchanged. The pattern and rate of deposition showed that positive particle-particle interactions

favored the formation of clusters of particles on the collector surface.

Keywords:

Particle deposition, Hydrotreating, particle filtration, pressure drop

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Introduction

Fine particles are commonly found in refinery process streams due corrosion of piping,

tank walls and vessels, entrainment from processes such as delayed coking, or from the

production of the oil as in the case of heavy oils and oilsands. Although desalting, distillation

and filtration remove most of the particles, low concentrations can persist in the feed streams to

packed-bed catalytic reactors such as hydrotreaters. Although these particles are typically

smaller than 20 µm in diameter, and hence smaller than the diameter of the flow channels

between the catalyst pellets, they are filtered from the liquid by deposition on the surface of the

catalyst pellets. This process is analogous to deep-bed filtration. Even if the efficiency of

removal is low, a few parts per million of particles can accumulate significantly during months

of operation. This accumulation can increase the pressure drop across the reactor catalyst beds to

the point where the reactor must be shut down, even though the catalyst activity is still

satisfactory (Chan et al. – ref; ??? Koyama et al., 1995). In order to help minimize this problem

in hydrotreater operation, a better understanding of the mechanisms involved in particle

deposition in nonaqueous media is essential.

The mechanisms of particle deposition have been studied extensively for aqueous media

(Elimelech and O’Melia 1990, Vatistas 1991), but not in non-aqueous media. Particle deposition

requires the arrival of a particle to the surface; attachment of a particle to the surface. Deposition

is determined by the balance between deposition and resuspension of a particle in the liquid

medium (Vatistas 1991). These processes are regulated by several factors, including the overall

kinetics of deposition onto a surface, the fluid dynamics of the flowing suspension, the surface

characteristics of the particles, and the physical properties of the suspension. The overall kinetics

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are determined by the rates of arrival, attachment, and resuspension. The arrival of particles to a

surface is governed by the size of the particles. Submicron particles are transported to the surface

as a result of convection and diffusion, while larger particles are transported to the surface as a

result of physical forces arising from gravity and fluid drag (Elimelech and O’Melia 1990).

The attachment of particles to a surface is regulated by van der Waals forces and by double layer

repulsion (Chowdiah et al. 1981, Elimelech and O’Melia 1990, van der Hoeven and Lyklema

1992, Visser 1995). The van der Waals interactions are determined by the properties of both the

particles and the surface, rather than the properties of the suspending medium. Thus, van der

Waals forces are important in both aqueous and non-aqueous systems. Any repulsion between a

particle and a surface is due to the presence of an electrostatic double layer repulsion. This

double layer repulsion forms when materials suspended in liquid acquire a charge which attracts

ions of the opposite charge, thereby forming a double layer. This phenomenon is well

documented for aqueous systems (Visser 1995), but van der Hoeven and Lyklema (1992) have

indicated that it is also a factor in non-aqueous systems. They concluded that in non-aqueous

systems, double layer repulsion is regulated by the dielectric constant, the ionic strength, the

surface potential, the Hamaker constant, and the particle size. They noted that these are the same

parameters that regulate double layer repulsion in aqueous media, but that the important

condition that must be met if a double layer repulsion is to form is that the ionic strength within

the medium must be sufficiently high. When the dielectric constant and the conductivity are low,

as in non-polar organic solvents, then the double layers are quite thick giving an extended range

for electrostatic interactions. The dielectric constant of a liquid hydrocarbon medium is less than

5, while that of water is approximately 80. Similarly, the electrical conductivity of a liquid

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hydrocarbon medium is several orders of magnitude lower than that of water (Chowdiah et al.

1981).

A unique characteristic of the behavior of fine particles in packed-bed catalytic reactors

is that the medium is a mixture of many different compounds, and this compositions can change

with position in the reactor due the action of the catalyst. In the case of hydrotreating, the

catalytic reactions convert compounds that contain sulfur and nitrogen, and to a lesser extent

oxygen, thereby liberating hydrogen sulfide, ammonia and water. These hydrogenation products

vaporize into the gas phase. As the liquid flows down through the catalyst bed, it gradually

changes from a solution of polar heteroatomic compounds in a hydrocarbon medium to a

solution of hydrocarbons alone.

One method for studying the step toward an understanding of the mechanisms that

regulate particle deposition in such non-aqueous media is to study a model system. Hydrotreaters

typically operate at temperatures over 300 °C and pressures over 3 MPa with two-phase flow of

liquid and vapor. The presence of a flowing gas gives much more complex time-varying

hydrodynamics than in single-phase flow. Both the catalyst and the fine particles will remain

liquid wet, therefore, the interactions between particles and the collector surface in a liquid phase

will control the deposition process. The objective of this study was to study the effect of

changing liquid-phase composition on the on particle deposition under controlled conditions,

using a model geometry and a model suspension. A jet of liquid impinging on a glass microscope

slide provided a well defined flow-field, and allowed direct observation of particle deposition.

The model suspension was fine particles suspended in kerosene, following van der Hoeven and

Lyklema (1992). The particles used were carbon black and kaolin particles, in order to examine

the role of the surface chemistry of the particles. Phenol and quinoline were added to the

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kerosene to evaluate the differences in deposition caused by more polar compounds that are

typical of hydrotreating. The dielectric constant and conductivity of each kerosene solution was

measured to monitor changes to the physical properties that could alter particle behavior.

Materials and Methods

Chemicals

Two types of particles were used in this study. Carbon black particles with an average

diameter of 0.2 µm were selected as a model for hydrophobic carbonaceous solids, such as coke.

Much of the fine particulate matter in bitumen consists of clay minerals with a surface layer of

adsorbed asphaltene and humic components (Chung et al., 1998). This material was simulated by

coating 0.5 µm particles of kaolin with asphaltenes, following the method of Yan and Masliyah

(1996). A 1 g sample of the asphaltene fraction of bitumen was dissolved in 500 mL of 50%

heptane/50% toluene mixture, then 2.5 g of kaolin particles were added and the resulting mixture

was stirred at 200 rpm for 24 hours. The particles were recovered by filtering the mixture

through a 0.22 µm membrane filter and drying under vacuum. Kerosene (Aldrich Chemical

Company, Inc., Milwaukee, Wisconsin), phenol (American Chemicals Ltd., Montreal, Quebec)

and quinoline (Aldrich Chemical Company, Inc., Milwaukee, Wisconsin) were used as received.

The dielectric constants of solutions consisting of pure kerosene, kerosene and phenol,

and kerosene and quinoline were determined by Dr. Wayne Tinga, Department of Electrical and

Computer Engineering, University of Alberta. The dielectric constants were measured by a

single frequency microwave at 915 MHz and 20oC (Tian et al. 1992; Tinga 1992).

The conductivity of each solution was determined by using a probe (Catalog #13-639-

123, Fisher Scientific Limited, Nepean, Ontario) connected to an electrometer (Model #617,

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Keithley Instruments, Inc., Cleveland, Ohio). The conductivity, x, was calculated from the

measured resistance, R, as follows:

Rkx /= (1)

where k is the cell constant determined from the measured resistance of a KCl solution with a

specific conductivity, x, of 0.1 S/cm.

Impinging Jet Apparatus

The impinging jet consisted of a capillary tube encased in a larger glass cell. The

diameter of the capillary tube was 2 mm, and the distance between the top of the capillary tube

and the top of the cell was 1.7 mm. The glass cell was 50 mm high, and had an inner diameter of

20 mm. A glass microscope slide was placed on top of the cell in such a way that there were no

air pockets or bubbles within the cell.

A beaker containing the particles suspended in kerosene was placed in an ultrasonic bath

(Model #1210R-MTH, Branson Ultrasonics Corporation, Danbury, Connecticut) in order to

disperse the particles. The suspension flowed from the beaker through the capillary tube into the

glass cell, and jetted towards the surface of the glass microscope slide. No chemical dispersant

was used to stabilize the suspension because the bubbles resulting from the presence of a

dispersant could not be eliminated. The liquid then exited the glass cell and flowed through a

glass tube into another beaker, from where it was pumped back into the beaker in the ultrasonic

bath. The glass exit tube, which had a diameter of 0.8 mm, controlled the velocity of the flowing

suspension through the impinging jet. The liquid flow rate was measured by a rotameter (Model

#FM-1050 Tube E627, Matheson Instruments, Montgomeryville, Pennsylvania). All experiments

were carried out at room temperature, 22±2oC. The glass cell was placed under a microscope

(Leitz Laborlux 12 ME S, Leica, Wetzlar, Germany) so that the stagnation point of the

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impinging jet was in the center of the viewing area. A video camera (Model #VCB-3514, Sanyo

Electric Co. Ltd., Osaka, Japan) was mounted on top of the 20 x microscope objective, and

images of the particles depositing on the glass slide surface were relayed to a VCR (Model #EV-

S5000, Sony Corporation, Park Ridge, New Jersey). The images were recorded over a period of

2 hours.

Data Analysis

A computer software package, Optimas (Optimas Corporation, Bothell, Washington),

was used to analyze the deposition rates of the particles. Using this software, images of the

particles on the microscope slide were saved at times from 3 to 120 min. The images were then

analyzed to determine the percentage of the area that was covered by particles at each time. The

total viewing area of the slide was 8 mm2.

Results

Deposition of Carbon Black Particles from an Impinging Jet

All experiments were conducted at a Reynolds number of 75 (flow rate 7.5 mL/min,

density 800 kg/m3, viscosity 0.0215 kg/m·s). The deposition of carbon black particles suspended

in kerosene at concentrations ranging from 5 to 20 mg/L is plotted as a function of time in Figure

1. At all carbon black concentrations, 2-dimensional clusters of particles formed until

approximately 50% of the glass microscope slide was covered with particles. An adjustment of

the microscope objective revealed that additional particles then began to adhere to the underside

of existing particles, giving 3-dimensional clusters. Once this particle-on-particle deposition had

begun, the fraction of the area covered by particles was no longer proportional to the number or

mass of particles deposited on the surface of the collector. The data obtained using a carbon

black concentration of 10 mg/L were the most reproducible, therefore, this concentration was

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used for all subsequent experiments. The data for the first 10 min of the experiments, i.e. at low

extents of deposition, at concentrations of 5, 10, and 20 mg/L are shown in Figure 2. The error

bars show the standard deviation for five repeated experiments.

Photographs of carbon black particles that deposited from a 10 mg/L suspension are

shown in Figure 3. Photograph (a), taken at 5 minutes, shows a few particles randomly

distributed on the surface. Photograph (b) was taken at 10 minutes, which corresponds to the

time when random deposition ceased. The 2-dimenstional clusters began to expand, as shown in

photograph (c), taken at 30 minutes, and these clusters started to form bridges between one

another in photograph (d), at 60 minutes. Once the bridging stage was complete, at

approximately 70 minutes, the particle-on-particle deposition began and the clusters became 3-

dimensional.

Deposition with Phenol and Quinoline

The data of Figure 4 show the deposition rate of carbon black particles at a concentration

of 10 mg/L when phenol was added to the kerosene at concentrations of 0.1, 5, 10, and 20 g/L.

This range of concentration of 0-4200 ppm oxygen content spans the range that would occur in

distillates from Athabasca bitumen. These curves were compared to the curve depicting carbon

black deposition when no phenol was present. This figure shows that as the amount of phenol

added to the kerosene increased to a concentration of 10 g/L, carbon black deposition on the

glass slide also increased. At a concentration of 20 g/L, the phenol was insoluble in kerosene,

and pockets of phenol were clearly visible on the surface of the glass slide. At lower phenol

concentrations, the particles were easily dispersed in the ultrasonic bath, since single particles

were observed coming out of the impinging jet and onto the glass microscope slide. However, 2-

dimensional flakes were observed in the collection beaker, indicating that aggregation occurred

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after the particles exited the glass cell. An adjustment of the microscope objective revealed that

particles did not adhere to the underside of existing particles when phenol was present at

concentrations of 10 g/L and lower, even after 60% of the glass slide was covered with the first

layer of particles.

In the presence of phenol at a concentration of 10 g/L, the particles deposited on the

surface randomly during the first 5 min of the experiments. This observation indicated that the

random deposition period was shorter in the presence of phenol than in the absence of phenol.

The 2-dimensional clusters that formed were larger than those in the absence of phenol. After 60

minutes, the formation of clusters slowed, and very few particles were deposited, either adjacent

to existing particles or on the underside of existing particles.

The data of Figure 5 show the deposition rate of carbon black particles at a concentration

of 10 mg/L on the glass slide at concentrations of 0, 7 and 15 g/L of quinoline, corresponding to

0-2000 ppm of nitrogen. The deposition rate of carbon black particles also increased as the

amount of quinoline was increased. In the presence of quinoline, spherical aggregates consisting

of approximately 10 carbon particles were observed exiting the impinging jet onto the glass

microscope slide. This observation suggested that the particles were not fully dispersed in the

ultrasonic bath in the presence of quinoline, and this formation of spherical aggregates meant

that a 3-dimensional structure always existed on the surface of the glass microscope slide. An

adjustment of the microscope objective, however, revealed that additional aggregates did not

deposit on the underside of these clusters until approximately 50% of the surface of the glass

microscope slide was covered.

The deposits of carbon black from a suspension with 15 g/L of quinoline were similar to

Figure 3. After 5 minutes, a few particles were randomly distributed on the surface of the glass

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microscope slide. After 10 minutes, the deposition of particles was mainly adjacent to existing

particles, and bridging began to occur at 60 minutes.

Figure 6 compares particle deposition without polar compounds and with phenol and

quinoline at 10 g/L and 15 g/L (0.11 and 0.12 M). Even though phenol is acidic and quinoline is

basic, both additives had a similar effect on deposition of carbon black.

Physical Properties of the Medium

The dielectric constant of pure kerosene was compared to solutions of kerosene with

phenol and quinoline at different concentrations, as shown in Table 1. Although kerosene was

non-polar and had a very low dielectric constant, the addition of either polar additive slightly

reduced the dielectric constant of the medium. The loss factor, which is used to describe the

energy absorption behavior of a material, increased in the presence of 10 mg/L phenol and in the

presence of 7 and 15 g/L quinoline. The loss tangent is the ratio of the loss factor to the dielectric

constant. The measurement uncertainty of the dielectric constant was estimated to be less than

±10%, and the measurement uncertainty of the loss factor was estimated to be less than ±15%

(Tinga 1998). The electrical conductivity of each solution is shown in Table 2. The solutions

containing polar additives had slightly lower conductivities than pure kerosene, although the data

show that regardless of the presence or absence of a polar additive, the solutions were not good

conductors. The changes in the values of the dielectric constant and electrical conductivity in the

presence of polar additives were not significant enough to account for the differences in particle

deposition.

Deposition of Kaolin Particles

Figure 7 compares the deposition of kaolin particles at a concentration of 10 mg/L to that

of carbon black particles at a concentration of 10 mg/L. The kaolin particles deposited randomly

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on the surface of the glass slide during the first three to five minutes of the experiment. Very few

additional particles deposited on the glass slide, however the few particles that did deposit on the

surface of the microscope slide after this time did not do so adjacent to existing particles. After 2

hours, only 9.3% of the glass microscope slide was covered with kaolin particles. The difference

in deposition between carbon black and kaolin indicates that the surface properties of the

particles themselves are major contributors to the particle deposition process in non-aqueous

media.

Discussion

The data in Figures 1 and 2 show that the curves that describe the deposition of carbon

black particles suspended in kerosene have a definite S-shape. This observation suggests that

single particles were able to adhere randomly to the glass slide quite rapidly at the start of the

experiment, while subsequent deposition was due to adhesion of particles immediately adjacent

to particles that had previously adhered to the surface of the glass microscope slide. The final

stage was formation of 3-dimensional clusters of particles. The combination of these three stages

of deposition resulted in an S-shaped curve. The changing rates of deposition that occur under all

conditions in this study indicate that the interactions between the particles and the media are

quite complex. The initial rapid deposition, followed by a reduction in adhesion of particles, was

consistent with electrostatic attraction as observed by Chowdiah et al. (1981). They found that

the rate of filtration of carbon black particles in a packed bed declined after the surface charge of

the packing had been neutralized by the deposition of particles with opposite charge. The

subsequent preferential attachment of particles adjacent to particles already deposited on the

surface showed that particle-particle interactions were more favorable than interaction with the

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glass surface. This favorable particle-particle interaction eventually led to bridging and three-

dimensional deposits.

When either phenol or quinoline were present in the liquid medium, more particles

deposited on the surface of the glass slide than without these polar compounds. Aggregation of

particles was not responsible for the increased deposition in the presence of phenol, since

aggregation did not occur until after the particles exited the glass cell. Aggregation did play a

role, however, in the increased deposition of carbon black particles in the presence of quinoline.

The aggregates consisted of approximately 10 particles. Since the aggregates were spherical, the

area covered by each aggregate is equivalent to that of approximately 3 or 4 single particles.

Thus, the aggregates would cover more of the area of the slide during the initial random

deposition period. Additional aggregates then had a larger “target” to adhere to, since additional

particles tended to deposit adjacent to existing particles. In all cases, i.e. kerosene only and with

addition of phenol or quinoline, most of the observed deposition was due to particle-particle

interactions, giving distinct growth of clumps of particles on the surface. Consequently, the

increase in deposition with increasing concentrations of phenol and quinoline was due to more

favorable particle-particle interactions. The extreme case was quinoline, where the particles

aggregated prior to deposition on the glass surface.

The changes in particle behavior cannot be attributed to changes in the properties of the

liquid medium. The dielectric constant and electrical conductivity of the kerosene solutions were

measured, but the changes in the physical properties were too small to explain changes in

particle behavior. The results in Tables 1 and 2 show that the addition of either phenol or

quinoline caused a slight reduction in the value of the dielectric constant and no change in the

electrical conductivity, except possibly the 10 g/L phenol solution. The uniformly low

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conductivity was consistent with the theory of conductivity in non-aqueous media, which

identifies charge carriers in low-dielectric media as micelles or large macro-ions, rather than

weakly polar solutes (Morrison, 1993).

Although the solutions were prepared and stored under low relative humidity, Morrison

(1993) has pointed out the difficulty of completely eliminating moisture. Trace amounts of water

in the solutions were, however, unlikely to alter the behavior of the carbon-black suspensions.

None of the suspensions showed a significant increase in conductivity, which would have

signalled micelle formation. Suspensions of hydrophobic particles, such as carbon black, are

generally unaffected by low levels of contamination by water, unlike hydrophilic mineral

surfaces (Morrison, 1993).

Since kerosene itself is nonpolar and does not tend to carry a charge, it is likely that the

trace amounts of water were the source of the double layer repulsion when pure kerosene was

used. At low concentrations, the water molecules would most likely dissociate into protons and

hydroxyl groups, which would adsorb onto the surface of the particles (Kitahara 1984). When

either phenol or quinoline was added to the suspension, the protons and hydroxyl groups

interacted with the additive, thus favoring deposition of particles onto the glass slide.

Another explanation for the role of phenol and quinoline is that these compounds

neutralized charges within the solution, leading to a reduction in the polarization ability of the

mixtures (Tinga 1998). This would mean that the condition imposed by van der Hoeven and

Lyklema (1992), that double layer repulsion could occur only if the medium had a “sufficiently

high ionic strength”, was met when pure kerosene was used as the medium. Thus, in the absence

14

of a polar additive, double layer repulsion would exist, thereby suppressing the attachment of

particles to the glass surface. When a small amount of either phenol or quinoline was added to

the medium, the neutralization of charges within the suspension reduced the effect of the double

layer repulsion, which favored deposition.

Deposition of the kaolin particles on the glass slide was not very favorable, as the

maximum particle coverage on the glass slide was 9.3% at the end of the experiment. After the

random deposition period, subsequent deposition did not occur adjacent to existing particles. The

decreased deposition of the kaolin particles, which had an average diameter 2.5 times greater

than the carbon black particles, may be due to its larger size, its surface charges, or both.

Submicron particles rely on Brownian motion to attain a surface, with smaller particles moving

faster than larger ones. The DLVO theory predicts that deposition depends on particle size,

however, work conducted by Elimelech and O’Melia (1990) suggests that this may not be true. It

is possible that in this study, the force with which the particles entered the glass cell was

sufficient to overcome any particle size limitations that would repress the diffusion of particles

out of the suspension onto the glass slide. This would have to be verified by conducting more

experiments involving a single type of particle with different well-defined size distributions.

The kaolin particles were more hydrophilic than the carbon black particles due to the

presence of hydroxyl groups on their surfaces. This would imply that electrical charges on the

surface of the particles played a role in deposition. As reviewed by Morrison (1993), there is

some dispute in the literature about whether or not particles suspended in nonaqueous media can

be charged. One view is that the sign of the charge of a certain particle may be either positive or

negative, depending on the basicity or acidity of the medium in which it is suspended. Kitahara

(1984) found that carbon black suspended in either benzene or cyclohexane with AOT carries a

15

negative charge, TiO2 suspended in cyclohexane with AOT carries a positive charge, carbon

black suspended in benzene with Mg(AOT)2 carries a positive charge, and TiO2 suspended in

cyclohexane with Mg(AOT)2 carries a positive charge. Thus, if the surfaces of carbon black and

kaolin suspended in kerosene carry opposite charges, differences in their deposition should be

expected.

Regardless of the relative role of the many factors involved in particle deposition in

nonaqueous media, the observations made in this study provide a starting point from which a

mechanism describing this process may be developed. The extent of particle deposition will

depend on the concentration of polar compounds, including water, in the medium, the ability of

the polar compounds to neutralize charges within the medium, and the surface properties of the

particles. Further research into the net effects of these components must be conducted if the

overall mechanism is to be fully understood.

16

References

Chan et al., 1994 ??

Chung, K.H.; Xu, S.; Gray, M.R.; Zhao, Y.; Kotlyar, L.; Sparks, B. “The chemistry, reactivity

and processability of Athabasca bitumen pitch.” Rev. Process Chem. Engin. 1, 41-79

(1998).

Chowdiah, P., D.T. Wasan, and D. Gidaspow, “Electrokinetic Phenomena in the Filtration of

Colloidal Particles Suspended in Nonaqueous Media”, AIChE Journal 27 (1981) 975-

984.

Elimelech, M. and C.R. O’Melia, “Kinetics of Deposition of Colloidal Particles in Porous

Media”, Environmental Science and Technology 24 (1990) 1528-1536.

Hoeven, Ph.C. van der and J. Lyklema, “Electrostatic Stabilization in Non-Aqueous Media”,

Advances in Colloid and Interface Science 42 (1992) 205-277.

Kitahara, A., “Nonaqueous Systems”, In: Surfactant Science Series Volume 15: Electrical

Phenomena at Interfaces. Fundamentals, Measurements, and Applications, A. Kitahara

and A. Watanabe, Eds., Marcel Dekker, New York (1984) 119-143.

Koyama, H., Nagai, E., Torii, H. and Kumagai, H. Oil Gas J. 1995, 93(47), 68.

Morrison, I., “Electrical Charges in Nonaqueous Media” Colloids and Surfaces A:

Physicochemical and Engineering Aspects 71 (1993) 1-37.

Tian, B.Q., W.R. Tinga, and W. Xi, “Single Frequency Microwave Dielectric Heating and

Measuring”, Materials Research Society Symposium Proceedings 269 (1992) 83-89.

Tinga, W.R., “Rapid High Temperature Measurement of Microwave Dielectric Properties”,

Materials Research Society Symposium Proceedings 269 (1992) 505-516.

Tinga, W.R., personal communication (1998).

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Vatistas, N., “Particle Adhesion to Surface Under Turbulent Flow Conditions”, In: Particles on

Surfaces 3, K.L. Mittal, Ed., Plenum Press, New York (1991) 17-27.

Visser, J., “Particle Adhesion and Removal: a Review”, Particulate Science and Technology 13

(1995) 169-196.

Yan, N. and J.H. Masliyah, “Effect of pH on Adsorption and Desorption of Clay Particles at Oil-

Water Interface”, Journal of Colloid and Interface Science 181 (1996) 20-27.

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Table 1: Dielectric Data Measured at 915 MHz and 20oC Using a Single Frequency

Dielectrometer

Medium Dielectric

Constant

Dielectric Loss

Factor

Loss Tangent

Kerosene only 2.0 0.0034 0.0017

0.1 g phenol/L 2.0 0.0012 0.00061

5 g phenol/L 1.6 0.00086 0.00054

10 g phenol/L 1.6 0.0048 0.0029

7 g quinoline/L 1.6 0.0038 0.0024

15 g quinoline/L 1.8 0.0052 0.0028

Table 2: Conductivity Data Determined from Resistances Measured by an

Electrometer

Medium Resistance (ohm) Conductivity (S/cm)

Kerosene only 8.33 E+10 1.47 E-07

0.1 g phenol/L 8.41 E+10 1.45 E-07

5 g phenol/L 8.87 E+10 1.38 E-07

10 g phenol/L 9.16 E+10 1.33 E-07

7 g quinoline/L 8.40 E+10 1.45 E-07

15 g quinoline/L 8.50 E+10 1.44 E-07

List of Figures

Figure 1. Adhesion of carbon black particles from a suspension in kerosene at particle concentrations from 5 to 20 mg/L.

Figure 2. Adhesion of carbon black particles from a suspension in kerosene at low extent

of surface coverage. Figure 3. Surface coverage by carbon black particles from a 10 mg/L suspension in

kerosene. a) 5 min; b) 10 min; c) 30 min; d) 60 min. Figure 4. Effect of phenol concentration on adhesion of carbon black particles to glass Figure 5. Effect of quinoline concentration on adhesion of carbon black particles to glass Figure 6. Comparison of particle deposition with time from kerosene and solutions with

phenol and kerosene. Figure 7. Comparison of deposition of carbon black and clay particles.

AbstractIntroductionMaterials and MethodsChemicalsImpinging Jet ApparatusData Analysis

ResultsDeposition of Carbon Black Particles from an Impinging JetDeposition with Phenol and QuinolinePhysical Properties of the MediumDeposition of Kaolin Particles

DiscussionReferencesList of Figures