Preface
Despite its existence in a high tech era, the paper
industry has become less efficient and more obsolescent since
mid-20th
century
My papermaking mentor, Art Rankin, is fond of saying:
“Papermaking is half physics and half chemistry.” Art’s injunction has
not penetrated to the lair of the machine manufacturers because they have
not demonstrated the capability of mixing chemicals and stock to
homogeneity. When we apply nanochemistry technology to the task,
chemical usage is reduced by 90-99%.
As for the chemical suppliers, they are perfectly
content to charge 90% extra for chemicals, and refuse to fund the
sensors
and computer control required to conduct the process at maximum
efficiency, quality and productivity.
While the rest of the world spins forward, the paper
industry is progressively dysfunctional and urgently needs effective
nanochemistry management.
Early Investigations
In 1991 the undersigned started intensive research
into the mechanisms underlying papermaking. Over a period of six years
we did more than 5000 lab and pilot plant experiments, leading to the
conclusion that dispersion and control of fine particles on a molecular
scale is central to papermaking.
During the decade of the 90’s we worked intensively
in the lab to perfect our understanding of the relationships between
finely divided particles, down to molecular scale, and their significance
to the art of papermaking.
We have now evaluated, refined, and quantified our
concepts as a process based on nanochemistry. Wet end chemical usage
will be decreased by 90-99%. Press section output consistency will
increase by 6-7%. Dryer section energy usage will decrease by at
least
50%.
In 1985 the undersigned started developing an online
sensor and computer system to continuously optimize and control the wet
end papermaking process. It is now called the Automatic Zeta Datatm
System and measures four key parameters in an 83-second cycle:
temperature, specific conductance, zeta potential (electrostatic surface
charge) and specific filtration resistance (drainage).
Computer control has been routinely practiced for
decades on the dry end. We propose installation of a sophisticated wet
end sensor system; highly effective equipment for mixing chemicals with
stock until homogeneous; measurement and control of homogeneity; and
computer control of chemical feed rates: a nanochemistry process.
Productivity will be maximized by simultaneously
increasing flow rates of the cationic and anionic components, holding the
net zeta potential at zero mV. The flow rates are controlled to maintain
a low level of SFR, (specific filtration resistance) which is reciprocal
to drainage. Maintaining the most appropriate level of SFR has the
effect of maximizing productivity.
Process Optimization
Current technology uses a flocculant to control
retention of fine particles and water removal, or drainage. It results
in impaired formation and a thicker, weaker sheet than use of coagulation
chemistry controlled by zeta potential.
When zeta potential control is properly used, with
precise neutralization of the repulsive surface charge, coagulation
chemistry is optimized, resulting in a thinner, smoother sheet,
at least
50% stronger.
The coagulation chemistry charge structure is weak in
its early wet process stages, unlike the flocculation mechanism;
therefore, agitation should be minimized. When agitation stops,
re-aggregation is instantaneous.
Because nanopaper is thinner, smoother and stronger,
a reasonable objective is to produce paper of vastly superior properties
with significantly less fiber, and sell it on a performance
basis.
Nanopaper should preferably be marketed by surface area, rather than by
weight.
This will represent a stunning change for a
dysfunctional industry, and result in markedly improve
profitability.
Implementation
In principle, two wet end mixing stations are
required, using mechanical mixing hardware, plus two Zeta
Datatm
Automatic Sensor Systems. We shall use two pages from the dry end
computer for nanochemistry control. This array will amply meet the needs
of the wet end and the press section.
Reducing the energy expended on dry end water removal
by at least 50% is technologically straightforward. It simply needs
expansion to the desired machine scale. About 25% is derived from
reduction of water re-wetting in the press section; and at least another
25% by azeotropic reduction of water vapor pressure in the dryer.
This is the first step towards recognizing the wisdom
of my mentor’s thesis that papermaking is half chemistry and half
physics. It importantly achieves the larger objective of raising paper
industry technology to approach the level shared by industry as a
whole.
John G. Penniman
www.papermaking-chemistry.com
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