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 Data^tm 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