U.S. patent application number 13/304785 was filed with the patent office on 2012-03-29 for method for monitoring organic deposits in papermaking.
Invention is credited to Prasad Duggirala, Sergey Sheychenko.
Application Number | 20120073775 13/304785 |
Document ID | / |
Family ID | 45869440 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120073775 |
Kind Code |
A1 |
Duggirala; Prasad ; et
al. |
March 29, 2012 |
METHOD FOR MONITORING ORGANIC DEPOSITS IN PAPERMAKING
Abstract
A method for monitoring the deposition of organic deposits from
a liquid or slurry in a papermaking process is disclosed. Also
disclosed is a method for measuring the effectiveness of inhibitors
that decrease the deposition of organic deposits in a papermaking
process. The method may involve monitoring the deposition of
organic deposits of a liquid or slurry that simulates the
conditions of a papermaking process. The methods may comprise the
steps of monitoring the rate of deposition of organic deposits;
adding an inhibitor that decreases the deposition of organic
deposits from the liquid or slurry; and optionally re-measuring the
rate of deposition of organic deposits from the liquid or slurry
onto the quartz crystal microbalance, with the rates of deposition
determined by measuring the vibration frequency of the quartz
crystal microbalance.
Inventors: |
Duggirala; Prasad;
(Naperville, IL) ; Sheychenko; Sergey; (Aurora,
IL) |
Family ID: |
45869440 |
Appl. No.: |
13/304785 |
Filed: |
November 28, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11148639 |
Jun 9, 2005 |
|
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13304785 |
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Current U.S.
Class: |
162/198 |
Current CPC
Class: |
G01N 2291/0256 20130101;
G01N 29/022 20130101; G01N 2291/02416 20130101; G01N 2291/0426
20130101; G01N 2291/0258 20130101; G01N 29/036 20130101; G01N
33/343 20130101 |
Class at
Publication: |
162/198 |
International
Class: |
D21F 13/00 20060101
D21F013/00 |
Claims
1. A method for monitoring and controlling a rate of deposition of
organic deposits from a liquid or slurry in a papermaking process,
the method comprising: providing a quartz crystal microbalance, the
quartz crystal microbalance having a top side in contact with the
liquid or slurry and a bottom side isolated from the liquid or
slurry, the quartz crystal microbalance measuring a vibration
frequency; monitoring the rate of deposition of the organic
deposits from the liquid or slurry by measuring the vibration
frequency; and adding an inhibitor to the liquid or slurry, the
inhibitor decreasing the rate of deposition of the organic deposits
from the liquid or slurry, wherein the adding is based upon the
monitoring.
2. The method of claim 1 wherein the top side of the quartz crystal
microbalance comprises at least one conductive material selected
from the group consisting of: platinum, titanium, silver; gold;
lead; cadmium; diamond-like thin film electrodes with or without
implanted ions; silicides of titanium, niobium and tantalum;
lead-selenium alloys; mercury amalgams; and silicon.
3. The method of claim 1 wherein the method is performed at a
location selected from the group consisting of: a pulp mill; a
papermaking machine; a tissue making machine; a repulper; water
loop; wet-end stock preparation; and a deinking stage.
4. The method of claim 1 wherein the organic deposits are selected
from the group consisting of at least one of the following: wood
extractives; related natural materials in virgin raw material;
redeposited lignin; defoamers; surfactants; mixtures of organic
insoluble salts; unsaponifiable organics; wood fibers; poorly
soluble polymeric paper additives; waxes; stickies, optionally
wherein the stickies are selected from the group consisting of
sizing chemicals and adhesives; and microbiological deposits.
5. The method of claim 1, wherein the liquid or slurry is a pulp
slurry.
6. A method for measuring the effectiveness of at least one
inhibitor that decreases a rate of deposition of organic deposits
in a papermaking process, the method comprising: providing a quartz
crystal microbalance, the quartz crystal microbalance having a top
side in contact with a liquid or slurry and a bottom side isolated
from the liquid or slurry, the quartz crystal microbalance
measuring a vibration frequency; monitoring the rate of deposition
of the organic deposits from the liquid or slurry by measuring the
vibration frequency; adding the at least one inhibitor that
decreases the rate of deposition of the organic deposits to the
liquid or slurry, wherein the adding is based upon the monitoring
step; and re-measuring the rate of deposition of the organic
deposits from the liquid or slurry on to the quartz crystal
microbalance by measuring the vibration frequency.
7. The method of claim 6 wherein the papermaking process occurs at
location selected from the group consisting of: a pulp mill; a
papermaking machine; a tissue making machine; a repulper; water
loop; wet-end stock preparation; and deinking stages.
8. A method for measuring the effectiveness of at least one
inhibitor that decreases a rate of deposition of organic deposits
in a papermaking process simulation, the method comprising:
providing a quartz crystal microbalance, the quartz crystal
microbalance having a top side in contact with a liquid or slurry
and a bottom side isolated from the liquid or slurry, the quartz
crystal microbalance measuring a vibration frequency; the liquid or
slurry simulating that of a liquid or slurry found in a papermaking
process; monitoring the rate of deposition of the organic deposits
from the liquid or slurry by measuring the vibration frequency;
adding the at least one inhibitor to the liquid or slurry, wherein
the adding is based upon the monitoring; and re-measuring the rate
of deposition of the organic deposits from the liquid or slurry by
measuring the vibration frequency.
9. The method of claim 4, wherein the surfactants are silicon
surfactants and optionally wherein the organic deposits are silicon
surfactants and the papermaking process is a tissue repulping
process.
10. The method of claim 1 wherein the top side of the quartz
crystal microbalance is coated with at least one material selected
from the group consisting of: polymeric films; monolayers;
polylayers; surfactants; polyelectrolites; thiols; silica; aromatic
sorbates; self-assembled monolayers; and molecular solids.
Description
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 11/148,639, filed Jun. 9, 2005, which is
herein incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention is in the field of papermaking. Specifically,
this invention is in the field of monitoring organic deposit
formation in a papermaking process.
BACKGROUND OF THE INVENTION
[0003] Formation of deposits of organic substances (wood
extractives and related natural materials in virgin raw material,
stickies, wax and microbiological components in recycled material)
is a common problem in papermaking. For paper grades, these
materials can become both undesirable components of papermaking
furnishes and troublesome deposits on all mill equipment.
[0004] The nature of the organic deposits differs from process to
process and from mill to mill. Most often, they are mixtures of
organic insoluble salts, unsaponifiable organics, wood fibers
and/or poorly soluble polymeric paper additives. In absence of
adequate chemical control, they form simultaneously with
microbiological deposits. Thereby, their deposition during the
production process is a quite complex matter due to these many
possible potential causes.
[0005] An express method for organic deposit monitoring and
prediction of the activities of deposit control programs is of
great value to the industry. Currently, there is no such method in
the market.
SUMMARY OF THE INVENTION
[0006] The present invention is directed toward methods of using a
quartz crystal microbalance in a papermaking process and in
benchtop testing of deposit control chemistries. The quartz crystal
microbalance of the invention has a top side in contact with the
liquid or slurry and a bottom side that is isolated from the liquid
or slurry.
[0007] The present invention provides for a method for monitoring
the deposition of organic deposits from an actual or model liquid
or slurry in a papermaking process comprising measuring the rate of
deposition of organic deposits from the liquid or slurry on to a
quartz crystal microbalance having a top side in contact with the
liquid or slurry and second bottom side isolated from the liquid or
slurry.
[0008] The present invention also provides for a method for
measuring the effectiveness of inhibitors (biocides in case of
microbiological deposits) that decrease the deposition of organic
deposits in a papermaking process comprising monitoring the
deposition of organic deposits from a liquid or slurry in a
papermaking process comprising measuring the rate of deposition of
organic deposits from the liquid or slurry on to a quartz crystal
microbalance having a top side in contact with the liquid or slurry
and second bottom side isolated from the liquid or slurry; adding
an inhibitor that decreases the deposition of organic deposits to
the liquid or slurry; and re-measuring the rate of deposition of
organic deposits from the liquid or slurry on to the quartz crystal
microbalance.
[0009] The present invention also provides for a method for
measuring the effectiveness of inhibitors that decrease the
deposition of organic deposits in a papermaking process comprising
measuring the deposition of organic deposits from a model liquid or
slurry that simulate a liquid or slurry found in a papermaking
process comprising measuring the rate of deposition of organic
deposits from the model liquid or slurry on to a quartz crystal
microbalance having a top side in contact with the liquid or slurry
and second bottom side isolated from the liquid or slurry;
repeating the measuring process under the same conditions in
presence of an inhibitor that decreases the deposition of organic
deposits to the liquid or slurry; and comparing the rates of
deposition of organic deposits from the liquid or slurry on to the
quartz crystal microbalance in the blank experiment in presence of
the inhibitor. The present invention is also directed toward a
method for monitoring and controlling a rate of deposition of
organic deposits from a liquid or slurry in a papermaking process.
The method comprises the steps of providing a crystal quartz
microbalance; monitoring the rate of deposition of the organic
deposits from the liquid or slurry by measuring the vibration
frequency; and adding an inhibitor to the liquid or slurry. The
inhibitor decreases the rate of deposition of the organic deposits
from the liquid or slurry, and the adding is based upon the
monitoring.
[0010] The present invention is also directed toward a method for
measuring the effectiveness of at least one inhibitor that
decreases a rate of deposition of organic deposits in a papermaking
process. The method comprises the steps of providing a quartz
crystal microbalance; monitoring the deposition of the organic
deposits from the liquid or slurry by measuring the vibration
frequency; adding the at least one inhibitor that decreases the
deposition of the organic deposits from the liquid or slurry; and
re-measuring the rate of deposition of the organic deposits from
the liquid or slurry onto the quartz crystal microbalance by
measuring the vibration frequency.
[0011] The present invention is also directed toward a method for
measuring the effectiveness of at least one inhibitor that
decreases a rate of deposition of organic deposits in a papermaking
process simulation. The method comprises the steps of providing a
quartz crystal microbalance; monitoring the rate of deposition of
the organic deposits from the liquid or slurry by measuring the
vibration frequency; adding the at least one inhibitor to the
liquid or slurry based on the monitoring; and re-measuring the rate
of deposition of the organic deposits from the liquid or slurry by
measuring the vibration frequency.
[0012] These and other features and advantages of the present
invention will be apparent from the following detailed description,
in conjunction with the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1. Formation of organic deposits in the post-oxygen
brownstock washer line: mass accumulation determined by measuring
vibration frequency of a quartz crystal microbalance.
[0014] FIG. 2. Deposition of wood resins and glued fines in the
paper machine (white water line) determined by measuring vibration
frequency of a quartz crystal microbalance. The deposition stops
upon adding an inhibitor at 11/25 moment.
[0015] FIG. 3. Deposition of wood resins and glued fines in the
paper machine (white water line): mass accumulation determined by
measuring vibration frequency of a quartz crystal microbalance.
[0016] FIG. 4. Wax (temperature-dependent adhesives) monitoring in
headbox furnish repulped at 60.degree. C. and gradually cooled down
(benchtop experiment): mass accumulation determined by measuring
vibration frequency of a quartz crystal microbalance, with the mass
corrected for changes in temperature. Notice slowing down the
deposition when temperature decreases with time (see FIG. 6).
[0017] FIG. 5. Wax monitoring in headbox furnish repulped at
60.degree. C. (benchtop experiment, FIG. 5): temperature.
[0018] FIG. 6. Mixed organic/inorganic deposition in D100 filtrate
discharge lines of a bleach plant, mass accumulation determined by
measuring vibration frequency of a quartz crystal microbalance.
[0019] FIG. 7. Mixed aluminum-calcium salt of a polymeric organic
acid (a scale inhibitor overdose, diagnostics in deposit control
program applications) in a white water line in the broke repulper:
mass accumulation determined by measuring vibration frequency of a
quartz crystal microbalance.
[0020] FIG. 8. Wood pitch deposition at a bleached Kraft pulp mill
(headbox).
[0021] FIG. 9. Synthetic pitch accumulation under mild acidic
conditions in presence of four pitch control chemicals at 60 ppm:
benchtop test, SRM.
[0022] FIG. 10. Synthetic pitch accumulation under mild acidic
conditions in presence of a pitch control chemical at doses 15-60
ppm.
[0023] FIG. 11. Monitoring microbiological growth at a recycle
board and packaging mill.
DETAILED DESCRIPTION OF THE INVENTION
[0024] "QCM" means quartz crystal microbalance.
[0025] "IDM" means independent deposition monitor. The instrument
is available from Nalco Company, Naperville, Ill. It is a portable
instrument that records actual deposition and, from the application
standpoint, differs from conventional coupons by its high
sensitivity and ability to continuously follow deposition and
assess the nature of the deposit. Data are collected continuously
at intervals ranging from minutes to hours and then downloaded from
the IDM to a personal computer. All plumbing is generally
accomplished using stainless steel tubing with compression
fittings. This includes the system's sample inlet and outlet. The
flow rate in a continuous operation (the probe connected to a
process line through a slipstream arrangement) is normally 2-4
gallons per minutes. The instrument also allows data collection
from a batch system, where the instrument probe is immersed into
the test liquid stirred using a mechanical or magnetic stirrer.
[0026] "DRM" means deposit rate monitor. The instrument is
available from Nalco Company, Naperville, Ill. It is an instrument
similar to IDM but without pressure compensation.
[0027] "SRM" means scale rate monitor. The instrument is available
from Nalco Company, Naperville, Ill. It is a benchtop instrument
based on QCM technology.
[0028] While the present invention is susceptible of embodiment in
various forms, there is shown in the drawings and will hereinafter
be described a presently preferred embodiment with the
understanding that the present disclosure is to be considered an
exemplification of the invention and is not intended to limit the
invention to the specific embodiment illustrated.
[0029] It should be further understood that the title of this
section of this specification, namely, "Detailed Description of the
Invention," relates to a requirement of the United States Patent
Office, and does not imply, nor should be inferred to limit the
subject matter disclosed herein.
[0030] The monitoring system is based on the QCM that is the main
part of the instrument's probe. Basic physical principles and
terminology of the QCM can be found in publications: Martin et al.,
Measuring liquid properties with smooth- and textured-surface
resonators, Proc. IEEE Int. Freq. Control Symp., v.47, p. 603-608
(1993); Martin et al., Resonator/Oscillator response to liquid
loading, Anal. Chem., v.69 (11), 2050-2054 (1997); Schneider et.
al., Quartz Crystal Microbalance (QCM) arrays for solution
analysis, Sandia Report SAND97-0029, p. 1-21 (1997). In the QCM, a
flat quartz crystal is sandwiched between two electrically
conductive surfaces. One surface (top side) is in a continuous
contact with the tested medium while the other (bottom side) is
isolated from the tested liquid or slurry. The QCM vibrates when
the electrical potential is applied (piezoelectric effect). The
oscillator frequency is connected to the amount of the deposit on
the top (open to the medium) side of the QCM. The vibration
frequency is, generally, linearly proportional to the mass of a
deposit on the metal surface of the QCM. Measuring the frequency
thus provides a means to monitor real-time deposition. The
oscillator frequency also is affected by the properties of the
aqueous phase such as a temperature and viscosity. Therefore,
uniform conditions should be maintained through every
experiment.
[0031] In one embodiment, the papermaking process occurs at
location selected from the group consisting of: a pulp mill; a
papermaking machine; a tissue making machine; a repulper; water
loop; wet-end stock preparation; and deinking stages.
[0032] In another embodiment, the organic deposits are selected
from the group consisting of: wood; extractives; redeposited
lignin; defoamers; surfactants; and stickies. In another
embodiment, the surfactants are silicon surfactants.
[0033] In another embodiment, the stickies are selected from the
group consisting of: sizing chemicals; and adhesives.
[0034] In another embodiment, the continuously flowing slurry is a
pulp slurry.
[0035] In another embodiment, the organic deposits are silicon
surfactants and the papermaking process is a tissue repulping
process.
[0036] In another embodiment, the top side of the quartz crystal
microbalance is made of one or more conductive materials selected
from the group consisting of: platinum; titanium; silver; gold;
lead; cadmium; diamond-like thin film electrodes with or without
implanted ions; silicides of titanium, niobium and tantalum;
lead-selenium alloys; mercury amalgams; and silicon.
[0037] In another embodiment, the top side of the quartz crystal
microbalance is coated with any one or more conductive or
unconductive materials selected from the group consisting of:
polymeric films; monolayers; polylayers; surfactants;
polyelectrolites; thiols; silica; aromatic sorbates; self-assembled
monolayers; and molecular solids.
[0038] In an embodiment, if an inhibitor is added to the liquid or
slurry but the vibration frequency of the quartz crystal
microbalance does not decrease as desired, the invention may add
more of the inhibitor until the vibration frequency decreases
accordingly.
[0039] The following examples not meant to limit the invention
unless otherwise stated in the claims appended hereto.
EXPERIMENTS
Example 1
[0040] The IDM instrument was directly connected (a slipstream
connection) to a filtrate line to assure a continuous flow of the
solution. The deposition was directly recorded and the data is
embodied in FIG. 1. Formation of "light" organic deposits in a
post-oxygen brownstock washer line was monitored on-line with the
IDM. Steady mass accumulation was observed. In several experiments,
the addition of Nalco chemical PP10-3095 led to deposit removal
followed by complete suppression of deposition (100-50 ppm) or
slowing the deposition down (25 ppm).
Example 2
[0041] The IDM instrument was directly connected (a slipstream
arrangement) to the white water line in the paper machine (0.3-0.5%
pulp fines). The deposition of wood resins and glued fines was
directly recorded and the data is embodied in FIG. 2. The
deposition stopped when Nalco chemical PP10-3095 was applied at 100
ppm (note that the chemical did not remove the material from the
surface of the QCM).
Example 3
[0042] The IDM instrument was directly connected (a slipstream
arrangement) to the white water line in the paper machine (0.3-0.5%
pulp fines). The deposition of wood resins and glued fines was
recorded and the data is embodied in FIG. 3. The deposition stopped
when Nalco chemical PP10-3095 was applied at 50 ppm and 100 ppm
(the chemical did not remove pitch from the surface of the
QCM).
Example 4
[0043] Silicon oil surfactants from facial tissue repulping process
(3% pulp, beaker, 400 rpm, room temperature, SRM instrument). In
this benchtop application, linear accumulation of the organic
deposit was observed, at a rate dependent of presence of deposit
control agents in the system.
Example 5
[0044] Wax (temperature-dependent adhesives) monitoring. A sample
of headbox furnish (100% recycled OCC box) was repulped at
60.degree. C. The slurry was transferred in a 1-L beaker with a
magnetic stirrer. The IDM probe was placed vertically on a stand
and the data is embodied in FIGS. 4 and 5. The slurry was stirred
at a constant rate 400 rpm at room temperature and allowed to cool
down. The data are corrected to 20.degree. C. using the
temperature-frequency linear correlation formula obtained for the
IDM instrument in a separate experiment. Mass accumulation could be
unambiguously ascribed to an organic material that deposits at a
noticeable rate while the solution is still warm, later deposition
slowed down.
Example 6
[0045] Mixed organic/inorganic deposits. This gives an example of
using the technique as both a monitoring and diagnostic tool. In a
paper mill, the IDM was installed, consecutively, in filtrate
discharge lines (pH 3.5-3.8, 60-66.degree. C.) where mixed barium
sulfate/calcium oxalate scale was thought to be depositing.
However, microphotographs of the deposit also indicated that the
scale is mixed, predominantly containing an organic component
(likely, trapped fibers and possibly viscous organic). The
instrument recorded deposition as illustrated in FIG. 6.
Example 7
[0046] Mixed aluminum-calcium salt of a polymeric organic acid (a
scale inhibitor overdose, diagnostics in deposit control program
applications). The IDM instrument was directly connected (a
slipstream arrangement) to the white water line in the broke
repulper (0.3-0.5% pulp fines). The deposition initially was
inorganic. The solution contained very high concentrations of metal
ions, especially aluminum and calcium. Application of an excess of
a scale control agent into the IDM line via peristaltic pump that
was a polymeric organic acid in its nature resulted in a surge of
deposition of a mixed aluminum-calcium salt of a polymeric organic
acid due to scale inhibitor overdose (FIG. 7).
Example 8
[0047] The DRM was installed at a bleached Kraft pulp mill in the
side stream of the primary screener headbox before the dryer, with
pulp flow at 1.5% consistency. The deposition of wood pitch was
recorded and the data is embodied in FIG. 8.
Example 9
[0048] To simulate pitch deposition, model pitch solution was added
to a 0.5% suspension of bleached Kraft pulp at pH 10.6, in presence
of inhibitors, when needled. A small amount of concentrated
solution of calcium chloride was added. Then the pH was decreased
to 2.5 with HCl, and subsequent pitch deposition was recorded using
an SRM instrument. The results are presented in FIGS. 9 and 10.
Example 10
[0049] The DRM was installed at a recycle board and packaging mill
in the side stream of the headbox before the dryer, with pulp flow
at 0.5% consistency. Due to the lack of a microbio control program
and heavily contaminated water, the mill has been experiencing
microbiological growth problems that interfered with the deposition
data. While no fiber is accumulating in the flow cell, bio-related
slime (identified upon inspection of the DRM probe) was building up
in the cell. Monitoring microbiological growth is illustrated in
FIG. 11.
[0050] All patents referred to herein, are hereby incorporated
herein by reference, whether or not specifically done so within the
text of this disclosure.
[0051] In the present disclosure, the words "a" or "an" are to be
taken to include both the singular and the plural. Conversely, any
reference to plural items shall, where appropriate, include the
singular.
[0052] From the foregoing it will be observed that numerous
modifications and variations can be effectuated without departing
from the true spirit and scope of the novel concepts of the present
invention. It is to be understood that no limitation with respect
to the illustrated specific embodiments or examples is intended or
should be inferred. The disclosure is intended to cover by the
appended claims all such modifications as fall within the scope of
the claims.
* * * * *